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Sample records for african rain forest

  1. Disturbance, diversity and distributions in Central African rain forest

    NARCIS (Netherlands)

    Gemerden, van B.S.

    2004-01-01

    The aim of this study is to gain insight in the impact of human land use on plant community composition, diversity and levels of endemism in Central African rain forest. Human disturbance in this region is causing large-scale habitat degradation. The two most widespread forms of land use are selecti

  2. Molecular phylogenetics reveal multiple tertiary vicariance origins of the African rain forest trees

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    Sosef Marc SM

    2008-12-01

    Full Text Available Abstract Background Tropical rain forests are the most diverse terrestrial ecosystems on the planet. How this diversity evolved remains largely unexplained. In Africa, rain forests are situated in two geographically isolated regions: the West-Central Guineo-Congolian region and the coastal and montane regions of East Africa. These regions have strong floristic affinities with each other, suggesting a former connection via an Eocene pan-African rain forest. High levels of endemism observed in both regions have been hypothesized to be the result of either 1 a single break-up followed by a long isolation or 2 multiple fragmentation and reconnection since the Oligocene. To test these hypotheses the evolutionary history of endemic taxa within a rain forest restricted African lineage of the plant family Annonaceae was studied. Molecular phylogenies and divergence dates were estimated using a Bayesian relaxed uncorrelated molecular clock assumption accounting for both calibration and phylogenetic uncertainties. Results Our results provide strong evidence that East African endemic lineages of Annonaceae have multiple origins dated to significantly different times spanning the Oligocene and Miocene epochs. Moreover, these successive origins (c. 33, 16 and 8 million years – Myr coincide with known periods of aridification and geological activity in Africa that would have recurrently isolated the Guineo-Congolian rain forest from the East African one. All East African taxa were found to have diversified prior to Pleistocene times. Conclusion Molecular phylogenetic dating analyses of this large pan-African clade of Annonaceae unravels an interesting pattern of diversification for rain forest restricted trees co-occurring in West/Central and East African rain forests. Our results suggest that repeated reconnections between the West/Central and East African rain forest blocks allowed for biotic exchange while the break-ups induced speciation via vicariance

  3. Fungus-Growing Termites Originated in African Rain Forest

    DEFF Research Database (Denmark)

    Aanen, Duur Kornelis; Eggleton, Paul

    2005-01-01

    are consumed (cf. [ [1] and [2] ]). Fungus-growing termites are found throughout the Old World tropics, in rain forests and savannas, but are ecologically dominant in savannas [ 3 ]. Here, we reconstruct the ancestral habitat and geographical origin of fungus-growing termites. We used a statistical model......Fungus-growing termites (subfamily Macrotermitinae, Isoptera) cultivate fungal crops (genus Termitomyces, Basidiomycotina) in gardens inside their colonies. Those fungus gardens are continuously provided with plant substrates, whereas older parts that have been well decomposed by the fungus...... extant savanna species are found in most genera, this moreover suggests that the savanna has repeatedly been colonized by fungus-growing termites. Furthermore, at least four independent "out-of-Africa" migrations into Asia, and at least one independent migration to Madagascar, have occurred. Although...

  4. GPS and GIS Methods in an African Rain Forest: Applications to Tropical Ecology and Conservation

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    Brean Duncan

    2002-01-01

    Full Text Available Since the completion of the Navstar Global Positioning System (GPS in 1995, the integration of GPS and Geographical Information Systems (GIS technology has expanded to a great number of ecological and conservation applications. In tropical rain forest ecology, however, the technology has remained relatively neglected, despite its great potential. Notwithstanding cost, this is principally due to (1 the difficulty of quality satellite reception beneath a dense forest canopy, and (2 a degree of spatial error unacceptable to fine-scale vegetation mapping. Here, we report on the technical use of GPS/GIS in the rain forest of Kibale National Park, Uganda, and the methodology necessary to acquire high-accuracy spatial measurements. We conclude that the stringent operating parameters necessary for high accuracy were rarely obtained while standing beneath the rain forest canopy. Raising the GPS antenna to heights of 25–30 m resolved this problem, allowing swift data collection on the spatial dispersion of individual rain forest trees. We discuss the impact of the 1996 Presidential Decision Directive that suspended U.S. military-induced GPS error on 1 May 2000, and comment on the potential applications of GPS/GIS technology to the ecological study and conservation of tropical rain forests.

  5. Phylogeography of the genus Podococcus (Palmae/Arecaceae) in Central African rain forests: Climate stability predicts unique genetic diversity.

    Science.gov (United States)

    Faye, A; Deblauwe, V; Mariac, C; Richard, D; Sonké, B; Vigouroux, Y; Couvreur, T L P

    2016-12-01

    The tropical rain forests of Central Africa contain high levels of species diversity. Paleovegetation or biodiversity patterns suggested successive contraction/expansion phases on this rain forest cover during the last glacial maximum (LGM). Consequently, the hypothesis of the existence of refugia e.g. habitat stability that harbored populations during adverse climatic periods has been proposed. Understory species are tightly associated to forest cover and consequently are ideal markers of forest dynamics. Here, we used two central African rain forest understory species of the palm genus, Podococcus, to assess the role of past climate variation on their distribution and genetic diversity. Species distribution modeling in the present and at the LGM was used to estimate areas of climatic stability. Genetic diversity and phylogeography were estimated by sequencing near complete plastomes for over 120 individuals. Areas of climatic stability were mainly located in mountainous areas like the Monts de Cristal and Monts Doudou in Gabon, but also lowland coastal forests in southeast Cameroon and northeast Gabon. Genetic diversity analyses shows a clear North-South structure of genetic diversity within one species. This divide was estimated to have originated some 500,000years ago. We show that, in Central Africa, high and unique genetic diversity is strongly correlated with inferred areas of climatic stability since the LGM. Our results further highlight the importance of coastal lowland rain forests in Central Africa as harboring not only high species diversity but also important high levels of unique genetic diversity. In the context of strong human pressure on coastal land use and destruction, such unique diversity hotspots need to be considered in future conservation planning.

  6. Rain Forest Murals

    Science.gov (United States)

    Kleiner, Cheryl

    2010-01-01

    The rain forest murals in the author's school began as a request from her principal to have students decorate the cafeteria with their own paintings. She decided to brainstorm ideas with her eighth-grade students. Taking into consideration the architectural space and the environmental concerns they wanted to convey, students chose the rain forest…

  7. Sulfur gases and aerosols in and above the equatorial African rain forest

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    Bingemer, H. G.; Andreae, M. O.; Andreae, T. W.; Artaxo, P.; Helas, G.; Jacob, D. J.; Mihalopoulos, N.; Nguyen, B. C.

    1992-04-01

    The distribution of gaseous and particulate sulfur compounds in the canopy of the tropical rain forest of northern Congo and the overlying atmosphere was determined during February 12-25, 1988. Hydrogen sulfide and dimethylsulfide decayed exponentially with altitude from approximately 30-40 ppt at ground level to 3-5 ppt at around 3 km altitude. Emission fluxes from the forest to the atmosphere were estimated by fitting a one-dimensional time-dependent numerical model of chemistry and transport of the sulfur compounds to their observed vertical profiles. Emission fluxes of 0.6-1.0 nmol H2S/sq m per min and 0.3-0.7 nmol DMS/sq m per min were consistent with the observed vertical profiles of H2S and DMS. These fluxes compare well with fluxes reported previously for the Amazon rain forest during the dry season and support the view of a subordinate role of land biota in the global cycling of sulfur. The particulate sulfur concentration of 248 ppt was found below the forest canopy. Biomass burning is considered to be an important contributor to this particulate sulfur. Carbonyl sulfide was found to be enhanced above the 500 ppt tropospheric background throughout the mixing layer of 2-3 km depth, likely due to biomass burning.

  8. The odd man out? Might climate explain the lower tree alpha-diversity of African rain forests relative to Amazonian rain forests?

    NARCIS (Netherlands)

    Parmentier, I.; Malhi, Y.; Senterre, B.; Whittaker, R.J.; Alonso, A.; Balinga, M.P.B.; Bakayoko, A.; Bongers, F.J.J.M.; Chatelain, C.; Comiskey, J.; Cortay, R.; Djuikouo Kamdem, M.N.; Doucet, J.L.; Gauier, L.; Hawthorne, W.D.; Issembe, Y.A.; Kouamé, F.N.; Kouka, L.; Leal, M.E.; Lejoly, J.; Lewis, S.L.; Newbery, D.; Nusbaumer, L.; Parren, M.P.E.; Peh, K.S.H.; Phillips, O.L.; Sheil, D.; Sonké, B.; Sosef, M.S.M.; Sunderland, T.; Stropp, J.; Steege, ter H.; Swaine, M.; Tchouto, P.; Gemerden, van B.S.; Valkenburg, van J.; Wöll, H.

    2007-01-01

    1. Comparative analyses of diversity variation among and between regions allow testing of alternative explanatory models and ideas. Here, we explore the relationships between the tree alpha-diversity of small rain forest plots in Africa and in Amazonia and climatic variables, to test the explanatory

  9. Rain Forest Dance Residency.

    Science.gov (United States)

    Watson, Dawn

    1997-01-01

    Outlines the author's experience as a dancer and choreographer artist-in-residence with third graders at a public elementary school, providing a cultural arts experience to tie in with a theme study of the rain forest. Details the residency and the insights she gained working with students, teachers, and theme. (SR)

  10. Species-specific growth responses to climate variations in understory trees of a Central African rain forest

    NARCIS (Netherlands)

    Couralet, C.; Sterck, F.J.; Sass-Klaassen, U.; Acker, Van J.; Beekman, H.

    2010-01-01

    Basic knowledge of the relationships between tree growth and environmental variables is crucial for understanding forest dynamics and predicting vegetation responses to climate variations. Trees growing in tropical areas with a clear seasonality in rainfall often form annual growth rings. In the und

  11. Hyperspectral Remote Sensing for Tropical Rain Forest

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    Kamaruzaman Jusoff

    2009-01-01

    Full Text Available Problem statement: Sensing, mapping and monitoring the rain forest in forested regions of the world, particularly the tropics, has attracted a great deal of attention in recent years as deforestation and forest degradation account for up to 30% of anthropogenic carbon emissions and are now included in climate change negotiations. Approach: We reviewed the potential for air and spaceborne hyperspectral sensing to identify and map individual tree species measure carbon stocks, specifically Aboveground Biomass (AGB and provide an overview of a range of approaches that have been developed and used to map tropical rain forest across a diverse set of conditions and geographic areas. We provided a summary of air and spaceborne hyperspectral remote sensing measurements relevant to mapping the tropical forest and assess the relative merits and limitations of each. We then provided an overview of modern techniques of mapping the tropical forest based on species discrimination, leaf chlorophyll content, estimating aboveground forest productivity and monitoring forest health. Results: The challenges in hyperspectral Imaging of tropical forests is thrown out to researchers in such field as to come with the latest techniques of image processing and improved mapping resolution leading towards higher precision mapping accuracy. Some research results from an airborne hyperspectral imaging over Bukit Nanas forest reserve was shared implicating high potential of such very high resolution imaging techniques for tropical mixed dipterocarp forest inventory and mapping for species discrimination, aboveground forest productivity, leaf chlorophyll content and carbon mapping. Conclusion/Recommendations: We concluded that while spaceborne hyperspectral remote sensing has often been discounted as inadequate for the task, attempts to map with airborne sensors are still insufficient in tropical developing countries like Malaysia. However, we demonstrated this with a case

  12. Surface response to rain events throughout the West African monsoon

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    F. Lohou

    2013-07-01

    Full Text Available This study analyses the response of the continental surface to a rain event, taking advantage of the long-term near-surface measurements over different vegetation covers at different latitudes, acquired during the African Monsoon Multidisciplinary Analysis (AMMA experiment. The simulated surface response by nine land surface models involved in AMMA Land Model Intercomparison Project (ALMIP, is compared to the observations. The surface response, described via the evaporative fraction, evolves in two steps: the immediate surface response and the surface recovery. The immediate surface response corresponds to an increase in the evaporative fraction occurring immediately after the rain. For all the experimental sites, the immediate surface response is strongest when the surface is relatively dry. From the simulation point of view, this relationship is highly model and latitude dependent. The recovery period, characterized by a decrease of the evaporative fraction during several days after the rain, follows an exponential relationship whose rate is vegetation dependent: from 1 day over bare soil to 70 days over the forest. Land surface models correctly simulate the decrease of EF over vegetation covers whereas a slower and more variable EF decrease is simulated over bare soil.

  13. A technique for collecting botanical specimens in rain forest

    NARCIS (Netherlands)

    Hyland, B.P.M.

    1972-01-01

    I. Introduction — The need for a simple method of collecting botanical material from rain-forest trees became evident during the construction of a field key to the rain-forest trees of North Queensland. Many collecting techniques have been developed, e.g. throwing sticks and stones, severing branche

  14. Millennial-scale dynamics of southern Amazonian rain forests.

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    Mayle, F E; Burbridge, R; Killeen, T J

    2000-12-22

    Amazonian rain forest-savanna boundaries are highly sensitive to climatic change and may also play an important role in rain forest speciation. However, their dynamics over millennial time scales are poorly understood. Here, we present late Quaternary pollen records from the southern margin of Amazonia, which show that the humid evergreen rain forests of eastern Bolivia have been expanding southward over the past 3000 years and that their present-day limit represents the southernmost extent of Amazonian rain forest over at least the past 50,000 years. This rain forest expansion is attributed to increased seasonal latitudinal migration of the Intertropical Convergence Zone, which can in turn be explained by Milankovitch astronomic forcing.

  15. Plant diversity after rain-forest fires in Borneo

    NARCIS (Netherlands)

    Eichhorn, Karl August Otto

    2006-01-01

    In the last two decades El-Niño-induced fires have caused widespread destruction of forests in East Kalimantan. The 1997-98 fires were the most extensive yet. The post-fire situation was studied in detail by field assessments and high-resolution SAR-images. My results show that rain forests are bett

  16. Vegetation and pollen rain relationship from the tropical Atlantic rain forest in Southern Brazil

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    Hermann Behling

    2006-07-01

    Full Text Available The relationship between the southern Brazilian tropical Atlantic lowland rain forest and modern pollen rain was studied by pollen traps. The study was carried out on a one hectare plot undisturbed rain forest of the reserve Volta Velha and two secondary forests, ± 50 and 7 years old. About 248 identified tree, shrub and herb species (excluding epiphytes of 50 families were represented by 126 different pollen and spore types (including non-local taxa. The calculated average influx of pollen rain from the native Atlantic rain forest was 12465 pollen grains per cm² and year. The influx from the ± 50 years old and from the 7 years old secondary forest was relatively low (4112 and 3667 grains per cm² and year, respectively compared to the undisturbed rain forest. The occurrence of pollen grains of herbs and fern spores were significantly higher in the secondary forests than in the undisturbed rain forest.Estudou-se a relação entre a Floresta Tropical Atlântica sul brasileira e a chuva polínica atual através de coletores de pólen. O estudo foi realizado em uma parcela de um hectare de floresta não perturbada localizada na Reserva Volta Velha (26º 04' S, 48º 38' W, 9 m s.n.m. e duas outras parcelas de floresta secundária (± 50 e 7 anos de idade. Cerca de 248 espécies arbóreas, arbustivas e herbáceas (excluindo epifitas, englobadas em 50 familias estavam representadas por 126 diferentes tipos de pólen e esporos (incluindo taxa não locais. Na área não perturbada, a média do fluxo de entrada da chuva polínica foi de 12465 grãos de pólen por cm²/ano. Nas áreas de ± 50 anos e 7 anos correspondentes a estádios florestais secundários o fluxo de entrada foi relativamente baixo (4112 e 3667 grãos por cm²/ano, respectivamente comparativamente à área não perturbada. A ocorrência de grãos de pólen de herbáceas e esporos de pteridófitas foi significativamente maior nas áreas secundárias do que na área não perturbada.

  17. Does a ruderal strategy dominate the endemic flora of the West African forests?

    NARCIS (Netherlands)

    Holmgren, M.; Poorter, L.

    2007-01-01

    Aim To understand the distribution pattern of endemic plant species in West African rain forests, one of the global priority areas for biodiversity conservation. Location Upper Guinean forests, West Africa (Senegal, Guinea-Bissau, Guinea, Sierra Leone, Liberia, Côte d'Ivoire, Ghana and Togo). Method

  18. Canopy dynamics of a tropical rain forest in French Guiana.

    NARCIS (Netherlands)

    Meer, van der P.J.

    1995-01-01

    The canopy dynamics (i.e. the formation and closure of canopy gaps) of a tropical rain forest in French Guiana are described. The formation of canopy gaps is investigated. The difficulties with gap size measurements are studied, and causes and consequences of treefalls and branchfalls are examined.

  19. Biomass and carbon dynamics of a tropical mountain rain forest in China

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Biometric inventories for 25 years,from 1983 to 2005,indicated that the Jianfengling tropical mountain rain forest in Hainan,China,was either a source or a modest sink of carbon.Overall,this forest was a small carbon sink with an accumulation rate of(0.56±0.22) Mg C ha-1yr-1,integrated from the long-term measurement data of two plots(P9201 and P8302).These findings were similar to those for African and American rain forests((0.62±0.23) Mg C ha-1yr-1).The carbon density varied between(201.43±29.38) Mg C ha-1 and(229.16±39.2) Mg C ha-1,and averaged(214.17±32.42) Mg C ha-1 for plot P9201.Plot P8302,however,varied between(223.95±45.92) Mg C ha-1 and(254.85±48.86) Mg C ha-1,and averaged(243.35±47.64) Mg C ha-1.Quadratic relationships were found between the strength of carbon sequestration and heavy rainstorms and dry months.Precipitation and evapotranspiration are two major factors controlling carbon sequestration in the tropical mountain rain forest.

  20. Valuation of consumption and sale of forest goods from a Central American rain forest

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    Godoy; Wilkie; Overman; Cubas; Cubas; Demmer; McSweeney; Brokaw

    2000-07-01

    Researchers recognize that society needs accurate and comprehensive estimates of the economic value of rain forests to assess conservation and management options. Valuation of forests can help us to decide whether to implement policies that reconcile the value different groups attach to forests. Here we have measured the value of the rain forest to local populations by monitoring the foods, construction and craft materials, and medicines consumed or sold from the forest by 32 Indian households in two villages in Honduras over 2.5 years. We have directly measured the detailed, comprehensive consumption patterns of rain forest products by an indigenous population and the value of that consumption in local markets. The combined value of consumption and sale of forest goods ranged from US$17.79 to US$23.72 per hectare per year, at the lower end of previous estimates (between US$49 and US$1,089 (mean US$347) per hectare per year). Although outsiders value the rain forest for its high-use and non-use values, local people receive a small share of the total value. Unless rural people are paid for the non-local values of rain forests, they may be easily persuaded to deforest.

  1. Tropical rain-forest matrix quality affects bat assemblage structure in secondary forest patches

    NARCIS (Netherlands)

    Vleut, I.; Levy-Tacher, I.; Galindo-Gonzalez, J.; Boer, de W.F.; Ramirez-Marcial, N.

    2012-01-01

    We studied Phyllostomidae bat assemblage structure in patches of secondary forest dominated by the pioneer tree Ochroma pyramidale, largely (.85%) or partially (,35%) surrounded by a matrix of tropical rain forest, to test 3 hypotheses: the highest bat diversity and richness is observed in the matri

  2. Multifractal analysis of African monsoon rain fields, taking into account the zero rain-rate problem

    Science.gov (United States)

    Verrier, S.; de Montera, L.; Barthès, L.; Mallet, C.

    2010-07-01

    SummaryNonlinear rain dynamics, due to strong coupling with turbulence, can be described by stochastic scale invariant (such as multifractal) models. In this study, attention is focused on the three-parameter fractionally integrated flux (FIF), based on the universal multifractal (UM) model developed by Schertzer and Lovejoy (1987). Multifractal analysis techniques were applied to experimental radar data measured during the African monsoon multidisciplinary analysis (AMMA) campaign, during the summer of 2006. The non-conservation parameter H, which has often been estimated at 0, was found to be more likely close to 0.4, meaning that rain is not a conserved cascade. Moreover, it is shown that the presence of numerous zero values in the data has an influence, which has until now been underestimated, but should in fact be accounted for. UM parameters are therefore estimated from the full dataset, and then only from maps in which almost all pixels have a non-zero value. Significant differences were found, attributed to on-off intermittency, and their role was checked by means of simulations. Finally, these results are compared with those previously based on time series, and collected by a co-localized disdrometer. The sets of parameters obtained in the spatial and time domains are found to be quite close to each other, contrary to most results published in the literature. This generally reported incoherency is believed to result mainly from the influence of on-off intermittency, whose effects are stronger for time series than for selected radar maps.

  3. Amazonia rain forest fires: A lacustrine record of 7000 years

    Energy Technology Data Exchange (ETDEWEB)

    Turcq, B.; Sifeddine, A. [Universidade Federal Fluminense, Niterol, RJ (Brazil). Dept. de Geoquimica; Martin, Louis [PPPG, Inst. de Geociencias, Salvador, BA (Brazil); Absy, M.L. [Inst. Nacional de Pesquisas Amazonicas, Manaus, AM (Brazil). Dept. de Botanica; Soubies, F. [Univ. Paul Sabatier, Toulouse (France). Lab. de Mineralogie; Suguio, Kenitiro [Sao Paulo Univ., SP (Brazil). Inst. de Geociencias; Volkmer-Ribeiro, C. [Fundacao Zoobotanica do Rio Grande do Sul, Porto Alegre, RS (Brazil)

    1998-03-01

    Although human influence dominates present-day Amazonian rain forest fires, old charcoal fragments, buried in the soils or in lacustrine sediments, confirm that fire has played a major role in the history of Amazonian forests. These fires may have influenced the present-day diversity and structure of the rain forest and, if these fire-favorable events of the past reoccur, there may be drastic consequences for the future of the Amazonian forests. Detailed studies of Carajas lake sediments permit identification of these past fire events, through microscopic observations of small charcoal fragments. They also permit, through radiocarbon dating, a better definition of their timing and make it possible to relate them to past paleo-environmental and paleoclimatic conditions. The paleodata indicate that fire events were concomitant with short dry climate episodes whose frequency of occurrences has varied during the last 7000 years. These dry events may be related to past climate conditions observed in different regions of tropical South America 23 refs, 3 figs

  4. Protecting rain forests and forager's rights using LANDSAT imagery

    Science.gov (United States)

    Wilkie, David S.

    1991-01-01

    Creating rain forest reserves is vital given the global decline in biodiversity. Yet, the plants and animals that will be protected from untrammeled commercial exploitation within such reserves constitute essential resources for indigenous foragers and farmers. Balancing the needs of local subsistence level populations with the goals of national and international conservation agencies requires a thorough understanding of the mutual impacts that arise from the interaction of park and people. In the Ituri forest of Zaire, LANDSAT TM image analysis and GPS ground truth data were used to locate human settlements so that boundaries of the proposed Okapi Reserve could be chosen to minimize its impact on the subsistence practices of the local foragers and farmers. Using satellite imagery in conjunction with cultural information should help to ensure traditional resource exploitation rights of indigenous peoples whilst simultaneously protecting the largest contiguous area of undisturbed forest.

  5. Tree rings in the tropics: a study on growth and ages of Bolivian rain forest trees

    NARCIS (Netherlands)

    Brienen, Roel Jacobus Wilhelmus

    2005-01-01

    Detailed information on long-term growth rates and ages of tropical rain forest trees is important to obtain a better understanding of the functioning of tropical rain forests. Nevertheless, little is known about long-term growth or ages of tropical forest trees, due to a supposed lack of annual tre

  6. The conservation value of small, isolated fragments of lowland tropical rain forest.

    Science.gov (United States)

    Turner, I M; T Corlett, R

    1996-08-01

    Deforestation is occurring at an alarming rate in the lowland tropics. In many tropical regions, rain forest is restricted to small (rainforest species that are on the brink of extinction. In areas with little rain forest remaining, fragments can be the 'seeds' from which to re-establish extensive forest.

  7. Canopy leaching of subtropical mixed forests under acid rain

    Institute of Scientific and Technical Information of China (English)

    Renjun XIANG; Liyuan CHAI; Xilin ZHANG; Gong ZHANG; Guifang ZHAO

    2008-01-01

    Leaching of major ions from acid precipitation in a subtropical forest was examined based on an experi-ment in four sample sites in Shaoshan City, Hunan Province, China, from January 2001 to June 2002. Results clearly show that when rain passed through the canopy, pH increased and the evidence of ion uptake was presented for SO42- , NO3-, Mg2+ and NH4+ ions, espe-cially of NH4+ and NO3-. The percentages of dissolved SO42-, Ca2+ and Mg2+ show a decreasing trend with increasing rainfall. Percentages of leaching Ca2+, K+ and Cl- ions show an increasing trend as a function of increased pH values. The forest canopy in Shaoshan City has a strong effect on the uptake of SO42- and NO3- ions under acid rain conditions. The decreasing order of ions leaching in the forest canopy is as follows: K+> Ca2+ > Cl- > Mg2+ > SO42- > NO3- > NH4+ > Na+.

  8. Seasonal trends of dry and bulk concentration of nitrogen compounds over a rain forest in Ghana

    Directory of Open Access Journals (Sweden)

    F. Fattore

    2013-09-01

    Full Text Available African tropical forests of the equatorial belt might receive significant input of extra nitrogen derived from biomass burning occurring in the north savanna belt and transported equator wards by NE winds. In order to test this hypothesis an experiment was set up in a tropical rain forest in the National park of Ankasa (Ghana aiming at: quantifying magnitude and seasonal variability of concentrations of N compounds, present as gas and aerosol (dry nitrogen or in the rainfall (bulk nitrogen, over the studied forest; relating their seasonal variability to trends of local and regional winds and rainfall and to variations of fire events in the region. Three Delta systems, implemented for monthly measurements of NO2, were mounted over a tower at 45 m height, 20 m above forest canopy to sample gas (NH3, NO2, HNO3, HCl, SO2 and aerosol (NH4+, NO3−, and several ions, together with three tanks for bulk rainfall collection (to analyze NH4+, NO3− and ion concentration. The tower was provided with a sonic anemometer to estimate local wind data. The experiment started in October 2011 and data up to October 2012 are presented. To interpret the observed seasonal trends of measured compounds, local and regional meteo data and regional satellite fire data were analyzed. The concentration of N compounds significantly increased from December to April, during the drier period, peaking in December-February when North Eastern winds (Harmattan were moving dry air masses over the West central African region and the inter tropical convergence zone (ITCZ was at its minimum latitude over the equator. This period also coincided with peaks of fire in the whole region. On the contrary, N concentration in gas, aerosol and rain decreased from May to October when prevalent winds arrived from the sea (South-East, during the Monsoon period. Both ionic compositions of rain and analysis of local wind direction showed a significant and continuous presence of see-breeze at site

  9. BIOGEOGRAPHICAL IMPLICATIONS OF SOME PLANT SPECIES FROM A TROPICAL MONTANE RAIN FOREST IN SOUTHERN YUNNAN

    Institute of Scientific and Technical Information of China (English)

    ZHU Hua

    2004-01-01

    A pristine montane rain forest was recently discovered from Mengsong of Xishuangbanna in the southern Yunnan.It attracts botanists that many primitive plant taxa across various life forms were co-existed in the montane rain forest.In order to know the biogeography of the montane rain forest,distribution patterns of some species of biogeographical importance from the montane forest were enumerated and their biogeographical implications were discussed with geological explanation.It was concluded that the montane rain forest in the southern Yunnan has strong affinity to montane rain forests in Sumatra or Southeast Asia in broad sense.It was tentatively suggested that Sumatra could be once connected to Myanmar and drifted away due to northward movement of continental Asia by bumping of India plate.

  10. Damage-controlled logging in managed tropical rain forest in Suriname.

    NARCIS (Netherlands)

    Hendrison, J.

    1990-01-01

    Concern about worldwide deforestation and exploitation of the tropical rain forests has led to friction between national governments, wood industries and timber trade on the one hand, and scientists and environmental organizations on the other. One way to safeguard the tropical rain forests is to av

  11. Regeneration in natural and logged tropical rain forest : modelling seed dispersal and regeneration

    NARCIS (Netherlands)

    Ulft, Lambertus Henricus van

    2004-01-01

    Regeneration and disturbance are thought to play key roles in the maintenance of the high tree species diversity in tropical rain forests. Nevertheless, the earliest stages in the regeneration of tropical rain forest trees, from seed production to established seedlings, have received little attenti

  12. Edge effect on palm diversity in rain forest fragments in western Ecuador

    DEFF Research Database (Denmark)

    Baez, S.; Balslev, Henrik

    2007-01-01

    to be idiosyncratic and to depend on the level of disturbance at edges. This paper explores how variation in forest structure at the edges of two old-growth forest fragments in a tropical rain forest in western Ecuador affects palms of different species, life-forms, and size classes. We investigate (1) how edge...

  13. Origin products from African forests

    DEFF Research Database (Denmark)

    Egelyng, Henrik; Bosselmann, Aske Skovmand; Warui, Mary;

    2016-01-01

    Many tropical countries have potential for adding market value to unique forest origin products similarly to how EU gain billions of Euro's annually from registering agricultural origin products, with Protected Denomination of Origin or Protected Geographical Indication. Following analysis...... presents major challenges for the development of GI products and markets, exemplified by the Kenyan GI bill which is not yet enacted after almost a decade in the making....... of the renaissance for the global Geographical Indication (GI) regime, this article provides case-studies from Kenya – on Mwingi Honey, Kakamega Silk and institutional conditions under which producers may incorporate territory specific cultural, environmental, and social qualities of their unique products. We...

  14. Geologic mapping of Indonesian rain forest with analysis of multiple SIR-B incidence angles

    Science.gov (United States)

    Ford, J. P.; Sabins, F. F., Jr.; Asmoro, P., Jr.

    1984-01-01

    The discrimination and mapping capabilities are to be evaluated for shuttle imaging radar-B (SIR-B) images of geologic features in Indonesia that are covered by equatorial rain forest canopy. The SIR-B backscatter from the rain forest at L-band is to be compared to backscatter acquired by the SEASAT scatterometer system at Ku-band ever corresponding areas. The approach for data acquisition, handling, and analysis and the expected results of the investigation are discussed.

  15. Seeds, saplings and gaps: size matters. A study in the tropical rain forest of Guyana

    OpenAIRE

    Rose, S A

    2001-01-01

    Forest management for timber exploitation is dependent on the succesful regeneration of commercial timber species in gaps. This study evaluated the influence of gap size and seed mass on the processes of seedling recruitment, establishment, growth and survival in logged over and mature forest areas over four years (1996-1999) in the tropical rain forest in Guyana. It generates insight into the potential impacts of logging on forest species diversity, and indicates necessary management procedu...

  16. Tropical Rain Forest and Climate Dynamics of the Atlantic Lowland, Southern Brazil, during the Late Quaternary

    Science.gov (United States)

    Behling, Hermann; Negrelle, Raquel R. B.

    2001-11-01

    Palynological analysis of a core from the Atlantic rain forest region in Brazil provides unprecedented insight into late Quaternary vegetational and climate dynamics within this southern tropical lowland. The 576-cm-long sediment core is from a former beach-ridge "valley," located 3 km inland from the Atlantic Ocean. Radio-carbon dates suggest that sediment deposition began prior to 35,000 14C yr B.P. Between ca. 37,500 and ca. 27,500 14C yr B.P. and during the last glacial maximum (LGM; ca. 27,500 to ca. 14,500 14C yr B.P.), the coastal rain forest was replaced by grassland and patches of cold-adapted forest. Tropical trees, such as Alchornea, Moraceae/Urticaceae, and Arecaceae, were almost completely absent during the LGM. Furthermore, their distributions were shifted at least 750 km further north, suggesting a cooling between 3°C and 7°C and a strengthening of Antarctic cold fronts during full-glacial times. A depauperate tropical rain forest developed as part of a successional sequence after ca. 12,300 14C yr B.P. There is no evidence that Araucaria trees occurred in the Atlantic lowland during glacial times. The rain forest was disturbed by marine incursions during the early Holocene period until ca. 6100 14C yr B.P., as indicated by the presence of microforaminifera. A closed Atlantic rain forest then developed at the study site.

  17. Response of soil respiration to acid rain in forests of different maturity in southern China.

    Directory of Open Access Journals (Sweden)

    Guohua Liang

    Full Text Available The response of soil respiration to acid rain in forests, especially in forests of different maturity, is poorly understood in southern China despite the fact that acid rain has become a serious environmental threat in this region in recent years. Here, we investigated this issue in three subtropical forests of different maturity [i.e. a young pine forest (PF, a transitional mixed conifer and broadleaf forest (MF and an old-growth broadleaved forest (BF] in southern China. Soil respiration was measured over two years under four simulated acid rain (SAR treatments (CK, the local lake water, pH 4.5; T1, water pH 4.0; T2, water pH 3.5; and T3, water pH 3.0. Results indicated that SAR did not significantly affect soil respiration in the PF, whereas it significantly reduced soil respiration in the MF and the BF. The depressed effects on both forests occurred mostly in the warm-wet seasons and were correlated with a decrease in soil microbial activity and in fine root biomass caused by soil acidification under SAR. The sensitivity of the response of soil respiration to SAR showed an increasing trend with the progressive maturity of the three forests, which may result from their differences in acid buffering ability in soil and in litter layer. These results indicated that the depressed effect of acid rain on soil respiration in southern China may be more pronounced in the future in light of the projected change in forest maturity. However, due to the nature of this field study with chronosequence design and the related pseudoreplication for forest types, this inference should be read with caution. Further studies are needed to draw rigorous conclusions regarding the response differences among forests of different maturity using replicated forest types.

  18. Response of soil respiration to acid rain in forests of different maturity in southern China.

    Science.gov (United States)

    Liang, Guohua; Liu, Xingzhao; Chen, Xiaomei; Qiu, Qingyan; Zhang, Deqiang; Chu, Guowei; Liu, Juxiu; Liu, Shizhong; Zhou, Guoyi

    2013-01-01

    The response of soil respiration to acid rain in forests, especially in forests of different maturity, is poorly understood in southern China despite the fact that acid rain has become a serious environmental threat in this region in recent years. Here, we investigated this issue in three subtropical forests of different maturity [i.e. a young pine forest (PF), a transitional mixed conifer and broadleaf forest (MF) and an old-growth broadleaved forest (BF)] in southern China. Soil respiration was measured over two years under four simulated acid rain (SAR) treatments (CK, the local lake water, pH 4.5; T1, water pH 4.0; T2, water pH 3.5; and T3, water pH 3.0). Results indicated that SAR did not significantly affect soil respiration in the PF, whereas it significantly reduced soil respiration in the MF and the BF. The depressed effects on both forests occurred mostly in the warm-wet seasons and were correlated with a decrease in soil microbial activity and in fine root biomass caused by soil acidification under SAR. The sensitivity of the response of soil respiration to SAR showed an increasing trend with the progressive maturity of the three forests, which may result from their differences in acid buffering ability in soil and in litter layer. These results indicated that the depressed effect of acid rain on soil respiration in southern China may be more pronounced in the future in light of the projected change in forest maturity. However, due to the nature of this field study with chronosequence design and the related pseudoreplication for forest types, this inference should be read with caution. Further studies are needed to draw rigorous conclusions regarding the response differences among forests of different maturity using replicated forest types.

  19. Screening of antibacterial extracts from plants native to the Brazilian Amazon Rain Forest and Atlantic Forest

    Directory of Open Access Journals (Sweden)

    Suffredini I.B.

    2004-01-01

    Full Text Available More than 20% of the world's biodiversity is located in Brazilian forests and only a few plant extracts have been evaluated for potential antibacterial activity. In the present study, 705 organic and aqueous extracts of plants obtained from different Amazon Rain Forest and Atlantic Forest plants were screened for antibacterial activity at 100 µg/ml, using a microdilution broth assay against Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa and Escherichia coli. One extract, VO581, was active against S. aureus (minimum inhibitory concentration (MIC = 140 µg/ml and minimal bactericidal concentration (MBC = 160 µg/ml, organic extract obtained from stems and two extracts were active against E. faecalis, SM053 (MIC = 80 µg/ml and MBC = 90 µg/ml, organic extract obtained from aerial parts, and MY841 (MIC = 30 µg/ml and MBC = 50 µg/ml, organic extract obtained from stems. The most active fractions are being fractionated to identify their active substances. Higher concentrations of other extracts are currently being evaluated against the same microorganisms.

  20. Hydrological consequences of land-use change from forest to pasture in the Atlantic rain forest region

    Directory of Open Access Journals (Sweden)

    Luiz Antonio Martinelli

    2012-12-01

    Full Text Available The Atlantic rain forest is the most endangered ecosystem in Brazil. Its degradation has started since 1500 when the European settlers arrived. Despite of all land use changes that have occurred, hydrological studies carried out in this biome have been limited to hydrological functioning of rain forests only. In order to understand the hydrological consequences of land-use change from forest to pasture, we described the hydrological functioning of a pasture catchment that was previously covered by tropical rain forest. To reach this goal we measured the precipitation, soil matric potential, discharge, surface runoff and water table levels during one year. The results indicated that there is a decrease in surface soil saturated hydraulic conductivity. However, as low intensity rainfall prevails, the lower water conductivity does not necessarily leads to a substantially higher surface runoff generation. Regarding soil water matric potential, the pasture presented higher moisture levels than forest during the dry season. This increase in soil moisture implies in higher water table recharge that, in turn, explain the higher runoff ratio. This way, land-use change conversion from forest to pasture implies a higher annual streamflow in pasture catchments. Nonetheless, this increase in runoff due to forest conversion to pasture implies in losses of biological diversity as well as lower soil protection.

  1. Transvalued species in an African forest.

    Science.gov (United States)

    Remis, Melissa J; Hardin, Rebecca

    2009-12-01

    We combined ethnographic investigations with repeated ecological transect surveys in the Dzanga-Sangha Dense Forest Reserve (RDS), Central African Republic, to elucidate consequences of intensifying mixed use of forests. We devised a framework for transvaluation of wildlife species, which means the valuing of species on the basis of their ecological, economic, and symbolic roles in human lives. We measured responses to hunting, tourism, and conservation of two transvalued species in RDS: elephants (Loxodonta cyclotis) and gorillas (Gorilla gorilla). Our methods included collecting data on encounter rates and habitat use on line transects. We recorded cross-cultural variation in ideas about and interactions with these species during participant observation of hunting and tourism encounters and ethnographic interviews with hunters, conservation staff, researchers, and tourists. Ecologically, gorillas used human-modified landscapes successfully, and elephants were more vulnerable than gorillas to hunting. Economically, tourism and encounters with elephants and gorillas generated revenues and other benefits for local participants. Symbolically, transvaluation of species seemed to undergird competing institutions of forest management that could prove unsustainable. Nevertheless, transvaluation may also offer alternatives to existing social hierarchies, thereby integrating local and transnational support for conservation measures. The study of transvaluation requires attention to transnational flows of ideas and resources because they influence transspecies interactions. Cross-disciplinary in nature, transvalution of species addresses the political and economic challenges to conservation because it recognizes the varied human communities that shape the survival of wildlife in a given site. Transvaluation of species could foster more socially inclusive management and monitoring approaches attuned to competing economic demands, specific species behaviors, and human

  2. Diurnal raptors in the fragmented rain forest of the Sierra Imataca, Venezuela

    Science.gov (United States)

    Alvarez, E.; Ellis, D.H.; Smith, D.G.; LaRue, C.T.; Bird, David M.; Varland, Daniel E.; Negro, Juan Jose

    1996-01-01

    The rain forest of the Sierra Imataca in eastern Venezuela has been subjected to extensive deforestation for pastures and agricultural settlements. In the last decade the opening of access roads combined with intensified logging and mining activities have fragmented a significant portion of the remaining forest. We noted local distribution and habitat use for 42 species of diurnal raptors observed in affected areas in this region. We observed some raptors considered as forest interior species and other open country species foraging and roosting in man-made openings inside the forest.

  3. Ecological studies on rain forest in Northern Suriname

    NARCIS (Netherlands)

    Schulz, J.P.

    1960-01-01

    During the years 1955-1957 ecological data were collected in various types of mesophytic forest occurring in the northern half of central Suriname (fig. 1). Physiognomically as well as floristically these forests correspond with the type of vegetation which in the other parts of tropical America gen

  4. Prolonged acid rain facilitates soil organic carbon accumulation in a mature forest in Southern China.

    Science.gov (United States)

    Wu, Jianping; Liang, Guohua; Hui, Dafeng; Deng, Qi; Xiong, Xin; Qiu, Qingyan; Liu, Juxiu; Chu, Guowei; Zhou, Guoyi; Zhang, Deqiang

    2016-02-15

    With the continuing increase in anthropogenic activities, acid rain remains a serious environmental threat, especially in the fast developing areas such as southern China. To detect how prolonged deposition of acid rain would influence soil organic carbon accumulation in mature subtropical forests, we conducted a field experiment with simulated acid rain (SAR) treatments in a monsoon evergreen broadleaf forest at Dinghushan National Nature Reserve in southern China. Four levels of SAR treatments were set by irrigating plants with water of different pH values: CK (the control, local lake water, pH ≈ 4.5), T1 (water pH=4.0), T2 (water pH=3.5), and T3 (water pH=3.0). Results showed reduced pH measurements in the topsoil exposed to simulated acid rains due to soil acidification. Soil respiration, soil microbial biomass and litter decomposition rates were significantly decreased by the SAR treatments. As a result, T3 treatment significantly increased the total organic carbon by 24.5% in the topsoil compared to the control. Furthermore, surface soil became more stable as more recalcitrant organic matter was generated under the SAR treatments. Our results suggest that prolonged acid rain exposure may have the potential to facilitate soil organic carbon accumulation in the subtropical forest in southern China.

  5. Central African biomes and forest succession stages derived from modern pollen data and plant functional types

    Directory of Open Access Journals (Sweden)

    J. Lebamba

    2009-07-01

    Full Text Available New detailed vegetation reconstructions are proposed in Atlantic Central Africa from a modern pollen data set derived from 199 sites (Cameroon, Gabon and Congo including 131 new sites. In this study, the concept of plant functional classification is improved with new and more detailed plant functional types (PFTs and new aggregations of pollen taxa. Using the biomisation method, we reconstructed (1 modern potential biomes and (2 potential succession stages of forest regeneration, a new approach in Atlantic Central African vegetation dynamics and ecosystem functioning reconstruction. When compared to local vegetation, potential biomes are correctly reconstructed (97.5% of the sites and tropical rain forest (TRFO biome is well identified from tropical seasonal forest (TSFO biome. When the potential biomes are superimposed on the White's vegetation map, only 76.4% of the sites are correctly reconstructed. But using botanical data, correspondence and cluster analyses, the 43 sites from Congo (Mayombe evidence more affinities with those of central Gabon and so they can also be considered as correctly reconstructed as TRFO biome and White's map should be revised. In terms of potential succession stages of forest regeneration, the mature forest (TMFO is well differentiated from the secondary forest (TSFE, but inside this latter group, the young and the pioneer stages are not clearly identified due probably to their low sampling representation. Moreover, linked to their progressive and mosaic character, the boundaries between two forest biomes or two forest stages are not clearly detected and need also a more intensive sampling in such transitions.

  6. The pristine rain forest? Remnants of historical human impacts on current tree species composition and diversity

    NARCIS (Netherlands)

    Gemerden, Barend S. van; Olff, Han; Parren, Marc P.E.; Bongers, Frans

    2003-01-01

    Aim: Tropical rain forests are often regarded as pristine and undisturbed by humans. In Central Africa, community-wide disturbances by natural causes are rare and therefore current theory predicts that natural gap phase dynamics structure tree species composition and diversity. However, the dominant

  7. Variation in photosynthetic light-use efficiency in a mountainous tropical rain forest in Indonesia

    DEFF Research Database (Denmark)

    Ibrom, Andreas; Oltchev, A.; June, T.

    2008-01-01

    in remote tropical areas. We used a 16-month continuous CO2 flux and meteorological dataset from a mountainous tropical rain forest in central Sulawesi, Indonesia to derive values of epsilon(Pg). and to investigate the relationship between P-g and Q(abs). Absorption was estimated with a 1D SVAT model from...

  8. Evaporation from rain-wetted forest in relation to canopy wetness, canopy cover, and net radiation

    NARCIS (Netherlands)

    Klaassen, W.

    2001-01-01

    Evaporation from wet canopies is commonly calculated using E-PM, the Penman-Monteith equation with zero surface resistance. However, several observations show a lower evaporation from rain-wetted forest. Possible causes for the difference between E-PM and experiments are evaluated to provide rules f

  9. Architecture of 53 rain forest tree species differing in adult stature and shade tolerance

    NARCIS (Netherlands)

    Poorter, L.; Bongers, F.J.J.M.; Sterck, F.J.; Wöll, H.

    2003-01-01

    Tree architecture determines a tree's light capture, stability, and efficiency of crown growth. The hypothesis that light demand and adult stature of tree species within a community, independently of each other, determine species' architectural traits was tested by comparing 53 Liberian rain forest

  10. How does tree age influence damage and recovery in forests impacted by freezing rain and snow?

    Science.gov (United States)

    Zhu, LiRong; Zhou, Ting; Chen, BaoMing; Peng, ShaoLin

    2015-05-01

    The response and recovery mechanisms of forests to damage from freezing rain and snow events are a key topic in forest research and management. However, the relationship between the degree of damage and tree age, i.e., whether seedlings, young trees, or adult trees are most vulnerable, remains unclear and is rarely reported. We investigated the effect of tree age on the degrees of vegetation damage and subsequent recovery in three subtropical forest types-coniferous, mixed, and broad-leaved-in the Tianjing Mountains, South China, after a series of rare icy rain and freezing snow events in 2008. The results showed that damage and recovery rates were both dependent on tree age, with the proportion of damaged vegetation increasing with age (estimated by diameter at breast height, DBH) in all three forest types and gradually plateauing. Significant variation occurred among forest types. Young trees in the coniferous forest were more vulnerable than those in the broad-leaved forest. The type of damage also varied with tree age in different ways in the three forest types. The proportion of young seedlings that were uprooted (the most severe type of damage) was highest in the coniferous forest. In the mixed forest, young trees were significantly more likely to be uprooted than seedlings and adult trees, while in the broad-leaved forest, the proportion of uprooted adult trees was significantly higher than that of seedlings and young trees. There were also differences among forest types in how tree age affected damage recovery. In the coniferous forest, the recovery rate of trees with broken trunks or crowns (DBH > 2.5 cm) increased with tree age. However, in the mixed and broad-leaved forests, no obvious correlation between the recovery rate of trees with broken trunks or crowns and tree age was observed. Trees with severe root damage did not recover; they were uprooted and died. In these forests, vegetation damage and recovery showed tree age dependencies, which varied

  11. Agaricomycetes in low land and montane Atlantic Rain Forest in Northeast Brazil

    Directory of Open Access Journals (Sweden)

    Tatiana Gibertoni

    2014-10-01

    Full Text Available The Atlantic Rain Forest represents a group of extra-amazonic forests, among which the coastal and montane (“brejos de altitude” are the most common in Northeast Brazil. Between 2011 and 2013, 110 field trips were performed in nine reserves in the domain of the Atlantic Rain Forest. Two thousand two hundred sixty three Agaricomycetes were collected and represented 271 species, among which several new species to science, new occurrences to the continent, country, region, biome and States were found. Besides recently collected material, 309 exsiccates of Agaricomycetes deposited in the Herbarium URM were revised and represented 38 species, among which several new occurrences to the region and States. The results indicate the importance of the constant inventories and also of revisions of material deposited in herbaria as tools to improve the knowledge about the Brazilian micota.

  12. African savanna-forest boundary dynamics

    DEFF Research Database (Denmark)

    Cuni Sanchez, Aida; White, Lee J. T.; Calders, Kim

    2016-01-01

    -term inventory plots we quantify changes in vegetation structure, above-ground biomass (AGB) and biodiversity of trees ≥10 cm diameter over 20 years for five vegetation types: savanna; colonising forest (F1), monodominant Okoume forest (F2); young Marantaceae forest (F3); and mixed Marantaceae forest (F4...

  13. Aboveground Biomass Modeling from Field and LiDAR Data in Brazilian Amazon Tropical Rain Forest

    Science.gov (United States)

    Silva, C. A.; Hudak, A. T.; Vierling, L. A.; Keller, M. M.; Klauberg Silva, C. K.

    2015-12-01

    Tropical forests are an important component of global carbon stocks, but tropical forest responses to climate change are not sufficiently studied or understood. Among remote sensing technologies, airborne LiDAR (Light Detection and Ranging) may be best suited for quantifying tropical forest carbon stocks. Our objective was to estimate aboveground biomass (AGB) using airborne LiDAR and field plot data in Brazilian tropical rain forest. Forest attributes such as tree density, diameter at breast height, and heights were measured at a combination of square plots and linear transects (n=82) distributed across six different geographic zones in the Amazon. Using previously published allometric equations, tree AGB was computed and then summed to calculate total AGB at each sample plot. LiDAR-derived canopy structure metrics were also computed at each sample plot, and random forest regression modelling was applied to predict AGB from selected LiDAR metrics. The LiDAR-derived AGB model was assessed using the random forest explained variation, adjusted coefficient of determination (Adj. R²), root mean square error (RMSE, both absolute and relative) and BIAS (both absolute and relative). Our findings showed that the 99th percentile of height and height skewness were the best LiDAR metrics for AGB prediction. The AGB model using these two best predictors explained 59.59% of AGB variation, with an Adj. R² of 0.92, RMSE of 33.37 Mg/ha (20.28%), and bias of -0.69 (-0.42%). This study showed that LiDAR canopy structure metrics can be used to predict AGC stocks in Tropical Forest with acceptable precision and accuracy. Therefore, we conclude that there is good potential to monitor carbon sequestration in Brazilian Tropical Rain Forest using airborne LiDAR data, large field plots, and the random forest algorithm.

  14. Impact of land use change on the hydrology and erosion of rain forest land in South Cameroon

    NARCIS (Netherlands)

    Waterloo, M.J.; Ntonga, J.C.; Dolman, A.J.; Ayangma, A.B.

    1997-01-01

    Rainfall, water, sediment yields and evaporation were quantified in three catchment areas with undisturbed rain forest, selectively logged forest, and forest with shifting cultivation respectively. Despite a considerable regional variation in rainfall(1700-2300 mm/a), annual evaporation rates were s

  15. Modern pollen-rain characteristics of tall terra firme moist evergreen forest, southern Amazonia

    Science.gov (United States)

    Gosling, William D.; Mayle, Francis E.; Tate, Nicholas J.; Killeen, Timothy J.

    2005-11-01

    The paucity of modern pollen-rain data from Amazonia constitutes a significant barrier to understanding the Late Quaternary vegetation history of this globally important tropical forest region. Here, we present the first modern pollen-rain data for tall terra firme moist evergreen Amazon forest, collected between 1999 and 2001 from artificial pollen traps within a 500 × 20 m permanent study plot (14°34'50″S, 60°49'48″W) in Noel Kempff Mercado National Park (NE Bolivia). Spearman's rank correlations were performed to assess the extent of spatial and inter-annual variability in the pollen rain, whilst statistically distinctive taxa were identified using Principal Components Analysis (PCA). Comparisons with the floristic and basal area data of the plot (stems ≥10 cm d.b.h.) enabled the degree to which taxa are over/under-represented in the pollen rain to be assessed (using R-rel values). Moraceae/Urticaceae dominates the pollen rain (64% median abundance) and is also an important constituent of the vegetation, accounting for 16% of stems ≥10 cm d.b.h. and ca. 11% of the total basal area. Other important pollen taxa are Arecaceae (cf. Euterpe), Melastomataceae/Combretaceae, Cecropia, Didymopanax, Celtis, and Alchornea. However, 75% of stems and 67% of the total basal area of the plot ≥10 cm d.b.h. belong to species which are unidentified in the pollen rain, the most important of which are Phenakospermum guianensis (a banana-like herb) and the key canopy-emergent trees, Erisma uncinatum and Qualea paraensis.

  16. Rain forest promotes trophic interactions and diversity of trap-nesting Hymenoptera in adjacent agroforestry.

    Science.gov (United States)

    Klein, Alexandra-Maria; Steffan-Dewenter, Ingolf; Tscharntke, Teja

    2006-03-01

    1. Human alteration of natural ecosystems to agroecosystems continues to accelerate in tropical countries. The resulting world-wide decline of rain forest causes a mosaic landscape, comprising simple and complex agroecosystems and patchily distributed rain forest fragments of different quality. Landscape context and agricultural management can be expected to affect both species diversity and ecosystem services by trophic interactions. 2. In Central Sulawesi, Indonesia, 24 agroforestry systems, differing in the distance to the nearest natural forest (0-1415 m), light intensity (37.5-899.6 W/m(-2)) and number of vascular plant species (7-40 species) were studied. Ten standardized trap nests for bees and wasps, made from reed and knotweed internodes, were exposed in each study site. Occupied nests were collected every month, over a period totalling 15 months. 3. A total of 13,617 brood cells were reared to produce adults of 14 trap-nesting species and 25 natural enemy species, which were mostly parasitoids. The total number of species was affected negatively by increasing distance from forest and increased with light intensity of agroforestry systems. The parasitoids in particular appeared to benefit from nearby forests. Over a 500-m distance, the number of parasitoid species decreased from eight to five, and parasitism rates from 12% to 4%. 4. The results show that diversity and parasitism, as a higher trophic interaction and ecosystem service, are enhanced by (i) improved connectivity of agroecosystems with natural habitats such as agroforestry adjacent to rain forest and (ii) management practices to increase light availability in agroforestry, which also enhances richness of flowering plants in the understorey.

  17. Degraded tropical rain forests possess valuable carbon storage opportunities in a complex, forested landscape

    Science.gov (United States)

    Alamgir, Mohammed; Campbell, Mason J.; Turton, Stephen M.; Pert, Petina L.; Edwards, Will; Laurance, William F.

    2016-07-01

    Tropical forests are major contributors to the terrestrial global carbon pool, but this pool is being reduced via deforestation and forest degradation. Relatively few studies have assessed carbon storage in degraded tropical forests. We sampled 37,000 m2 of intact rainforest, degraded rainforest and sclerophyll forest across the greater Wet Tropics bioregion of northeast Australia. We compared aboveground biomass and carbon storage of the three forest types, and the effects of forest structural attributes and environmental factors that influence carbon storage. Some degraded forests were found to store much less aboveground carbon than intact rainforests, whereas others sites had similar carbon storage to primary forest. Sclerophyll forests had lower carbon storage, comparable to the most heavily degraded rainforests. Our findings indicate that under certain situations, degraded forest may store as much carbon as intact rainforests. Strategic rehabilitation of degraded forests could enhance regional carbon storage and have positive benefits for tropical biodiversity.

  18. Degraded tropical rain forests possess valuable carbon storage opportunities in a complex, forested landscape

    Science.gov (United States)

    Alamgir, Mohammed; Campbell, Mason J.; Turton, Stephen M.; Pert, Petina L.; Edwards, Will; Laurance, William F.

    2016-01-01

    Tropical forests are major contributors to the terrestrial global carbon pool, but this pool is being reduced via deforestation and forest degradation. Relatively few studies have assessed carbon storage in degraded tropical forests. We sampled 37,000 m2 of intact rainforest, degraded rainforest and sclerophyll forest across the greater Wet Tropics bioregion of northeast Australia. We compared aboveground biomass and carbon storage of the three forest types, and the effects of forest structural attributes and environmental factors that influence carbon storage. Some degraded forests were found to store much less aboveground carbon than intact rainforests, whereas others sites had similar carbon storage to primary forest. Sclerophyll forests had lower carbon storage, comparable to the most heavily degraded rainforests. Our findings indicate that under certain situations, degraded forest may store as much carbon as intact rainforests. Strategic rehabilitation of degraded forests could enhance regional carbon storage and have positive benefits for tropical biodiversity. PMID:27435389

  19. Degraded tropical rain forests possess valuable carbon storage opportunities in a complex, forested landscape.

    Science.gov (United States)

    Alamgir, Mohammed; Campbell, Mason J; Turton, Stephen M; Pert, Petina L; Edwards, Will; Laurance, William F

    2016-07-20

    Tropical forests are major contributors to the terrestrial global carbon pool, but this pool is being reduced via deforestation and forest degradation. Relatively few studies have assessed carbon storage in degraded tropical forests. We sampled 37,000 m(2) of intact rainforest, degraded rainforest and sclerophyll forest across the greater Wet Tropics bioregion of northeast Australia. We compared aboveground biomass and carbon storage of the three forest types, and the effects of forest structural attributes and environmental factors that influence carbon storage. Some degraded forests were found to store much less aboveground carbon than intact rainforests, whereas others sites had similar carbon storage to primary forest. Sclerophyll forests had lower carbon storage, comparable to the most heavily degraded rainforests. Our findings indicate that under certain situations, degraded forest may store as much carbon as intact rainforests. Strategic rehabilitation of degraded forests could enhance regional carbon storage and have positive benefits for tropical biodiversity.

  20. Decoupled leaf and stem economics in rain forest trees.

    Science.gov (United States)

    Baraloto, Christopher; Timothy Paine, C E; Poorter, Lourens; Beauchene, Jacques; Bonal, Damien; Domenach, Anne-Marie; Hérault, Bruno; Patiño, Sandra; Roggy, Jean-Christophe; Chave, Jerome

    2010-11-01

    Cross-species analyses of plant functional traits have shed light on factors contributing to differences in performance and distribution, but to date most studies have focused on either leaves or stems. We extend these tissue-specific analyses of functional strategy towards a whole-plant approach by integrating data on functional traits for 13 448 leaves and wood tissues from 4672 trees representing 668 species of Neotropical trees. Strong correlations amongst traits previously defined as the leaf economics spectrum reflect a tradeoff between investments in productive leaves with rapid turnover vs. costly physical leaf structure with a long revenue stream. A second axis of variation, the 'stem economics spectrum', defines a similar tradeoff at the stem level: dense wood vs. high wood water content and thick bark. Most importantly, these two axes are orthogonal, suggesting that tradeoffs operate independently at the leaf and at the stem levels. By simplifying the multivariate ecological strategies of tropical trees into positions along these two spectra, our results provide a basis to improve global vegetation models predicting responses of tropical forests to global change.

  1. Diversity and aboveground biomass of lianas in the tropical seasonal rain forests of Xishuangbanna, SW China.

    Science.gov (United States)

    Lü, Xiao-Tao; Tang, Jian-Wei; Feng, Zhi-Li; Li, Mai-He

    2009-01-01

    Lianas are important components of tropical forests and have significant impacts on the diversity, structure and dynamics of tropical forests. The present study documented the liana flora in a Chinese tropical region. Species richness, abundance, size-class distribution and spatial patterns of lianas were investigated in three 1-ha plots in tropical seasonal rain forests in Xishuangbanna, SW China. All lianas with > or = 2 cm diameter at breast height (dbh) were measured, tagged and identified. A total of 458 liana stems belonging to 95 species (ranging from 38 to 50 species/ha), 59 genera and 32 families were recorded in the three plots. The most well-represented families were Loganiaceae, Annonceae, Papilionaceae, Apocynaceae and Rhamnaceae. Papilionaceae (14 species recorded) was the most important family in the study forests. The population density, basal area and importance value index (IVI) varied greatly across the three plots. Strychnos cathayensis, Byttneria grandifolia and Bousigonia mekongensis were the dominant species in terms of IVI across the three plots. The mean aboveground biomass of lianas (3 396 kg/ha) accounted for 1.4% of the total community above-ground biomass. The abundance, diversity and biomass of lianas in Xishuangbanna tropical seasonal rain forests are lower than those in tropical moist and wet forests, but higher than those in tropical dry forests. This study provides new data on lianas from a geographical region that has been little-studied. Our findings emphasize that other factors beyond the amount and seasonality of precipitation should be included when considering the liana abundance patterns across scales.

  2. Interannual modulation of East African early short rains by the winter Arctic Oscillation

    Science.gov (United States)

    Gong, Dao-Yi; Guo, Dong; Mao, Rui; Yang, Jing; Gao, Yongqi; Kim, Seong-Joong

    2016-08-01

    In the present study, we analyzed the interannual linkage between the boreal winter Arctic Oscillation (AO) and East African early short rains. When the Indian Ocean Dipole and El Niño-Southern Oscillation variance are excluded by linear regression, the boreal winter AO index is significantly correlated with the October East African precipitation over the domain of 5°N-5°S and 35°-45°E for the period 1979-2014, r =+ 0.46. The upper ocean heat content likely acts as a medium that links the AO and East African precipitation. Significant subsurface warming and positive upper ocean heat content anomalies occur over the western Indian Ocean during the autumn following positive AO winters, which enriches the atmospheric moisture, intensifies convection, and enhances precipitation. Oceanic dynamics play a key role in causing this subsurface warming. Winter AO-related atmospheric circulation creates anomalous wind stress, which forces a downwelling oceanic Rossby wave between 60°-75°E and 5°-10°S, where the thermocline significantly deepens. This Rossby wave propagates westward and accompanies significant subsurface warming along the thermocline. The Rossby wave arrives at the western Indian Ocean in the late summer, significantly warming the region to the west of 55°E at a depth of 60-100 m. This warming remains significant through October. Correspondingly, the upper ocean heat content significantly increases by approximately 2-3 × 108 J m-2 in the region west of 60°E between 5° and 10°S. The role of these oceanic dynamics in linking the winter AO, and anomalous subsurface warming was tested by numerical experiments with an oceanic general circulation model. The experiments were performed with the forcing of AO-related wind stress anomalies over the Indian Ocean in the winter. The oceanic Rossby wave generated in the central Indian Ocean during boreal winter, the consequent subsurface warming, and the anomalous upper ocean heat content in October over the

  3. Dual-Frequency Interferometric SAR Observations of a Tropical Rain-Forest

    Science.gov (United States)

    Rigot, E.

    1996-01-01

    Repeat-pass, interferometric, radar observations of tropical rain-forest collected by the Shuttle Imaging Radar C (SIR-C) in the state of Rondonia, Brazil, reveal signal coherence is destroyed at C-band (5.6-cm) in the forest, whereas L-band (24-cm) radar signals remain strongly coherent over the entire landscape. At L-band, the rms difference in inferred topographic height between the forest and adjacent clearings is 5 m, equivalent to the height noise. Atmospheric delays are large, however, forming kilometer-sized anomalies with a 1.2-cm rms one way. Radar interferometric studies of the humid tropics must therefore be conducted at long radar wavelengths, with kilometric base-lines or with two antennas operating simultaneously.

  4. Aerosol number fluxes over the Amazon rain forest during the wet season

    Directory of Open Access Journals (Sweden)

    P. Artaxo

    2009-12-01

    Full Text Available Number fluxes of particles with diameter larger than 10 nm were measured with the eddy covariance method over the Amazon rain forest during the wet season as part of the LBA (The Large Scale Biosphere Atmosphere Experiment in Amazonia campaign 2008. The primary goal was to investigate whether sources or sinks dominate the aerosol number flux in the tropical rain forest-atmosphere system.

    During the measurement campaign, from 12 March to 18 May, 60% of the particle fluxes pointed downward, which is a similar fraction to what has been observed over boreal forests. The net deposition flux prevailed even in the absolute cleanest atmospheric conditions during the campaign and therefore cannot be explained only by deposition of anthropogenic particles. The particle transfer velocity vt increased with increasing friction velocity and the relation is described by the equation vt = 2.4×10−3×u* where u* is the friction velocity.

    Upward particle fluxes often appeared in the morning hours and seem to a large extent to be an effect of entrainment fluxes into a growing mixed layer rather than primary aerosol emission. In general, the number source of primary aerosol particles within the footprint area of the measurements was small, possibly because the measured particle number fluxes reflect mostly particles less than approximately 200 nm. This is an indication that the contribution of primary biogenic aerosol particles to the aerosol population in the Amazon boundary layer may be low in terms of number concentrations. However, the possibility of horizontal variations in primary aerosol emission over the Amazon rain forest cannot be ruled out.

  5. Height-related changes in leaf photosynthetic traits in diverse Bornean tropical rain forest trees.

    Science.gov (United States)

    Kenzo, Tanaka; Inoue, Yuta; Yoshimura, Mitsunori; Yamashita, Megumi; Tanaka-Oda, Ayumi; Ichie, Tomoaki

    2015-01-01

    Knowledge of variations in morphophysiological leaf traits with forest height is essential for quantifying carbon and water fluxes from forest ecosystems. Here, we examined changes in leaf traits with forest height in diverse tree species and their role in environmental acclimation in a tropical rain forest in Borneo that does not experience dry spells. Height-related changes in leaf physiological and morphological traits [e.g., maximum photosynthetic rate (Amax), stomatal conductance (gs), dark respiration rate (Rd), carbon isotope ratio (δ(13)C), nitrogen (N) content, and leaf mass per area (LMA)] from understory to emergent trees were investigated in 104 species in 29 families. We found that many leaf area-based physiological traits (e.g., A(max-area), Rd, gs), N, δ(13)C, and LMA increased linearly with tree height, while leaf mass-based physiological traits (e.g., A(max-mass)) only increased slightly. These patterns differed from other biomes such as temperate and tropical dry forests, where trees usually show decreased photosynthetic capacity (e.g., A(max-area), A(max-mass)) with height. Increases in photosynthetic capacity, LMA, and δ(13)C are favored under bright and dry upper canopy conditions with higher photosynthetic productivity and drought tolerance, whereas lower R d and LMA may improve shade tolerance in lower canopy trees. Rapid recovery of leaf midday water potential to theoretical gravity potential during the night supports the idea that the majority of trees do not suffer from strong drought stress. Overall, leaf area-based photosynthetic traits were associated with tree height and the degree of leaf drought stress, even in diverse tropical rain forest trees.

  6. Large-Scale Mapping of Tree-Community Composition as a Surrogate of Forest Degradation in Bornean Tropical Rain Forests

    Directory of Open Access Journals (Sweden)

    Shogoro Fujiki

    2016-12-01

    Full Text Available Assessment of the progress of the Aichi Biodiversity Targets set by the Convention on Biological Diversity (CBD and the safeguarding of ecosystems from the perverse negative impacts caused by Reducing Emissions from Deforestation and Forest Degradation Plus (REDD+ requires the development of spatiotemporally robust and sensitive indicators of biodiversity and ecosystem health. Recently, it has been proposed that tree-community composition based on count-plot surveys could serve as a robust, sensitive, and cost-effective indicator for forest intactness in Bornean logged-over rain forests. In this study, we developed an algorithm to map tree-community composition across the entire landscape based on Landsat imagery. We targeted six forest management units (FMUs, each of which ranged from 50,000 to 100,000 ha in area, covering a broad geographic range spanning the most area of Borneo. Approximately fifty 20 m-radius circular plots were established in each FMU, and the differences in tree-community composition at a genus level among plots were examined for trees with diameter at breast height ≥10 cm using an ordination with non-metric multidimensional scaling (nMDS. Subsequently, we developed a linear regression model based on Landsat metrics (e.g., reflectance value, vegetation indices and textures to explain the nMDS axis-1 scores of the plots, and extrapolated the model to the landscape to establish a tree-community composition map in each FMU. The adjusted R2 values based on a cross-validation approach between the predicted and observed nMDS axis-1 scores indicated a close correlation, ranging from 0.54 to 0.69. Histograms of the frequency distributions of extrapolated nMDS axis-1 scores were derived from each map and used to quantitatively diagnose the forest intactness of the FMUs. Our study indicated that tree-community composition, which was reported as a robust indicator of forest intactness, could be mapped at a landscape level to

  7. Effect of Simulated Acid Rain on Potential Carbon and Nitrogen Mineralization in Forest Soils

    Institute of Scientific and Technical Information of China (English)

    OUYANG Xue-Jun; ZHOU Guo-Yi; HUANG Zhong-Liang; LIU Ju-Xiu; ZHANG De-Qiang; LI Jiong

    2008-01-01

    Acid rain is a serious environmental problem worldwide. In this study, a pot experiment using forest soils planted with the seedlings of four woody species was performed with weekly treatments of pH 4.40, 4.00, 3.52, and 3.05 simulated acid rain (SAR) for 42 months compared to a control of pH 5.00 lake water. The cumulative amounts of C and N mineralization in the five treated soils were determined after incubation at 25 ℃ for 65 d to examine the effects of SAR treatments.For all five treatments, cumulative CO2-C production ranged from 20.24 to 27.81 mg kg-1 dry soil, net production of available N from 17.37 to 48.95 mg kg-1 dry soil, and net production of NO-3-N from 9.09 to 46.23 mg kg-1 dry soil. SAR treatments generally enhanced the emission of CO2-C from the soils; however, SAR with pH 3.05 inhibited the emission.SAR treatments decreased the net production of available N and NO3-N. The cumulative CH4 and N2O productions from the soils increased with increasing amount of simulated acid rain. The cumulative CO2-C production and the net production of available N of the soil under Acmena acuminatissima were significantly higher (P≤0.05) than those under Schima superba and Cryptocarya concinna. The mineralization of soil organic C was related to the contents of soil organic C and N, but was not related to soil pH. However, the overall effect of acid rain on the storage of soil organic matter and the cycling of important nutrients depended on the amount of acid deposition and the types of forests.

  8. Tree species control rates of free-living nitrogen fixation in a tropical rain forest.

    Science.gov (United States)

    Reed, Sasha C; Cleveland, Cory C; Townsend, Alan R

    2008-10-01

    Tropical rain forests represent some of the most diverse ecosystems on earth, yet mechanistic links between tree species identity and ecosystem function in these forests remains poorly understood. Here, using free-living nitrogen (N) fixation as a model, we explore the idea that interspecies variation in canopy nutrient concentrations may drive significant local-scale variation in biogeochemical processes. Biological N fixation is the largest "natural" source of newly available N to terrestrial ecosystems, and estimates suggest the highest such inputs occur in tropical ecosystems. While patterns of and controls over N fixation in these systems remain poorly known, the data we do have suggest that chemical differences among tree species canopies could affect free-living N fixation rates. In a diverse lowland rain forest in Costa Rica, we established a series of vertical, canopy-to-soil profiles for six common canopy tree species, and we measured free-living N fixation rates and multiple aspects of chemistry of live canopy leaves, senesced canopy leaves, bulk leaf litter, and soil for eight individuals of each tree species. Free-living N fixation rates varied significantly among tree species for all four components, and independent of species identity, rates of N fixation ranged by orders of magnitude along the vertical profile. Our data suggest that variations in phosphorus (P) concentration drove a significant fraction of the observed species-specific variation in free-living N fixation rates within each layer of the vertical profile. Furthermore, our data suggest significant links between canopy and forest floor nutrient concentrations; canopy P was correlated with bulk leaf litter P below individual tree crowns. Thus, canopy chemistry may affect a suite of ecosystem processes not only within the canopy itself, but at and beneath the forest floor as well.

  9. Evidence of Late Palaeocene-Early Eocene equatorial rain forest refugia in southern Western Ghats, India

    Indian Academy of Sciences (India)

    V Prasad; A Farooqui; S K M Tripathi; R Garg; B Thakur

    2009-11-01

    Equatorial rain forests that maintain a balance between speciation and extinction are hot-spots for studies of biodiversity. Western Ghats in southern India have gained attention due to high tropical biodiversity and endemism in their southern most area. We attempted to track the affinities of the pollen flora of the endemic plants of Western Ghat area within the fossil palynoflora of late Palaeocene-early Eocene (∼55–50 Ma) sedimentary deposits of western and northeastern Indian region. The study shows striking similarity of extant pollen with twenty eight most common fossil pollen taxa of the early Palaeogene. Widespread occurrences of coal and lignite deposits during early Palaeogene provide evidence of existence of well diversified rain forest community and swampy vegetation in the coastal low lying areas all along the western and northeastern margins of the Indian subcontinent. Prevalence of excessive humid climate during this period has been seen as a result of equatorial positioning of Indian subcontinent, superimposed by a long term global warming phase (PETM and EECO) during the early Palaeogene. The study presents clear evidence that highly diversified equatorial rain forest vegetation once widespread in the Indian subcontinent during early Palaeogene times, are now restricted in a small area as a refugia in the southernmost part of the Western Ghat area. High precipitation and shorter periods of dry months seem to have provided suitable environment to sustain lineages of ancient tropical vegetation in this area of Western Ghats in spite of dramatic climatic changes subsequent to the post India-Asia collision and during the Quaternary and Recent times.

  10. Diaspore bank of bryophytes in tropical rain forests: the importance of breeding system, phylum and microhabitat.

    Science.gov (United States)

    Maciel-Silva, Adaíses S; Válio, Ivany Ferraz Marques; Rydin, Håkan

    2012-02-01

    Diaspore banks are crucial for the maintenance and resilience of plant communities, but diaspore banks of bryophytes remain poorly known, especially from tropical ecosystems. This is the first study to focus on the role of diaspore banks of bryophytes in tropical rain forests. Our aim was to test whether microhabitat (substrate type) and species traits (breeding system, phylum) are important in explaining the diaspore bank composition. Using samples cultivated in the laboratory, we assessed the number of species and shoots emerging from bark, decaying wood and soil from two sites of the Atlantic rain forest (montane and sea level) in Brazil by comparing the contribution of species by phylum (mosses, liverworts) and breeding system (monoicous, dioicous). More species emerged from bark (68) and decaying wood (55) than from soil (22). Similar numbers of species were found at both sites. Mosses were more numerous in terms of number of species and shoots, and monoicous species dominated over dioicous species. Substrate pH had only weak effects on shoot emergence. Species commonly producing sporophytes and gemmae had a high contribution to the diaspore banks. These superficial diaspore banks represented the extant vegetation rather well, but held more monoicous species (probably short-lived species) compared to dioicous ones. We propose that diaspore bank dynamics are driven by species traits and microhabitat characteristics, and that short-term diaspore banks of bryophytes in tropical rain forests contribute to fast (re)establishment of species after disturbances and during succession, particularly dioicous mosses investing in asexual reproduction and monoicous mosses investing in sexual reproduction.

  11. Topographic and spatial controls of palm species distributions in a montane rain forest, southern Ecuador

    DEFF Research Database (Denmark)

    Svenning, J.-C.; Harlev, D.; Sørensen, M.M.;

    2009-01-01

    location as factors controlling species distributions in a palm community in a montane rain forest landscape in the Andes of southern Ecuador (1900-2150 m above sea level). Eleven species were present: Aiphanes verrucosa, Ceroxylon parvifrons, Chamaedorea pinnatifrons, Dictyocaryum lamarckianum, Euterpe......-association of some species corresponded to their general elevational ranges in southern Ecuador, this was not the case for other species. Based on such considerations, we conclude that elevational climatic gradients are likely to only form part of the explanation for the topographic effects on palm species...

  12. The genetic population structure of wild western lowland gorillas (Gorilla gorilla gorilla) living in continuous rain forest.

    Science.gov (United States)

    Fünfstück, Tillmann; Arandjelovic, Mimi; Morgan, David B; Sanz, Crickette; Breuer, Thomas; Stokes, Emma J; Reed, Patricia; Olson, Sarah H; Cameron, Ken; Ondzie, Alain; Peeters, Martine; Kühl, Hjalmar S; Cipolletta, Chloe; Todd, Angelique; Masi, Shelly; Doran-Sheehy, Diane M; Bradley, Brenda J; Vigilant, Linda

    2014-09-01

    To understand the evolutionary histories and conservation potential of wild animal species it is useful to assess whether taxa are genetically structured into different populations and identify the underlying factors responsible for any clustering. Landscape features such as rivers may influence genetic population structure, and analysis of structure by sex can further reveal effects of sex-specific dispersal. Using microsatellite genotypes obtained from noninvasively collected fecal samples we investigated the population structure of 261 western lowland gorillas (WLGs) (Gorilla gorilla gorilla) from seven locations spanning an approximately 37,000 km(2) region of mainly continuous rain forest within Central African Republic (CAR), Republic of Congo and Cameroon. We found our sample to consist of two or three significantly differentiated clusters. The boundaries of the clusters coincided with courses of major rivers. Moreover, geographic distance detoured around rivers better-explained variation in genetic distance than straight line distance. Together these results suggest that major rivers in our study area play an important role in directing WLG gene flow. The number of clusters did not change when males and females were analyzed separately, indicating a lack of greater philopatry in WLG females than males at this scale.

  13. Impact of logging on aboveground biomass stocks in lowland rain forest, Papua New Guinea.

    Science.gov (United States)

    Bryan, Jane; Shearman, Phil; Ash, Julian; Kirkpatrick, J B

    2010-12-01

    Greenhouse-gas emissions resulting from logging are poorly quantified across the tropics. There is a need for robust measurement of rain forest biomass and the impacts of logging from which carbon losses can be reliably estimated at regional and global scales. We used a modified Bitterlich plotless technique to measure aboveground live biomass at six unlogged and six logged rain forest areas (coupes) across two approximately 3000-ha regions at the Makapa concession in lowland Papua New Guinea. "Reduced-impact logging" is practiced at Makapa. We found the mean unlogged aboveground biomass in the two regions to be 192.96 +/- 4.44 Mg/ha and 252.92 +/- 7.00 Mg/ha (mean +/- SE), which was reduced by logging to 146.92 +/- 4.58 Mg/ha and 158.84 +/- 4.16, respectively. Killed biomass was not a fixed proportion, but varied with unlogged biomass, with 24% killed in the lower-biomass region, and 37% in the higher-biomass region. Across the two regions logging resulted in a mean aboveground carbon loss of 35 +/- 2.8 Mg/ha. The plotless technique proved efficient at estimating mean aboveground biomass and logging damage. We conclude that substantial bias is likely to occur within biomass estimates derived from single unreplicated plots.

  14. Assessment of organochlorine pesticide residues in Atlantic Rain Forest fragments, Rio de Janeiro, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Soares Quinete, Natalia, E-mail: nataliaquinete@yahoo.com.br [Instituto Nacional de Tecnologia, Departamento de Quimica Analitica, Laboratorio de Quimica Analitica e Metrologia em Quimica, Av. Venezuela, 82 - Rio de Janeiro, RJ 20081-312 (Brazil); Santos de Oliveira, Elba dos [Instituto Nacional de Tecnologia, Departamento de Energia, Av. Venezuela, 82 - Rio de Janeiro, RJ 20081-312 (Brazil); Fernandes, Daniella R. [Universidade Federal do Rio de Janeiro, Instituto de Quimica, Departamento de Quimica Analitica, CT - Bloco A, Cidade Universitaria, 21941-909 - Rio de Janeiro (Brazil); Souza Avelar, Andre de [Universidade Federal do Rio de Janeiro, Departamento de Geografia, Instituto de Geociencias, CCMN, Bloco F, Cidade Universitaria, 21941-919 - Rio de Janeiro (Brazil); Erthal Santelli, Ricardo [Universidade Federal do Rio de Janeiro, Instituto de Quimica, Departamento de Quimica Analitica, CT - Bloco A, Cidade Universitaria, 21941-909 - Rio de Janeiro (Brazil)

    2011-12-15

    A superficial water quality survey in a watershed of the Paraiba do Sul River, the main water supply for the most populated cities of southeastern Brazil, was held in order to assess the impact of the expansion of agricultural activity in the near border of the Atlantic Rain Forest. The aim of this study was to investigate the presence of priority organochlorine pollutants in soils and superficial waters of Atlantic rainforest fragments in Teresopolis, Rio de Janeiro State. Soil sample preparations were compared by using ultrasound, microwave assisted extraction and Soxhlet extraction. Recoveries of matrix spiked samples ranged from 70 to 130%. Analysis of a certified soil material showed recoveries ranging from 71 to 234%. Although low concentrations of organochlorine residues were found in water and soil samples, this area is of environmental importance and concern, thus demanding a monitoring program of its compartments. - Highlights: > The organochlorine pollutants occurrence in the Atlantic Rain Forest was investigated. > PARNASO was considered a control area of environmental quality. > Extractions methods were compared for typical C-rich soils samples from Brazil. > Low concentrations of organochlorine residues were found in water and soil samples. > A monitoring program is demanded due to the environmental importance of the area. - The occurrence of organochlorine pollutants in soils of the Atlantic rainforest fragments in Rio de Janeiro, Brazil demands a monitoring program of its compartments.

  15. Production of Alkaline Cellulase by Fungi Isolated from an Undisturbed Rain Forest of Peru

    Directory of Open Access Journals (Sweden)

    Karin Vega

    2012-01-01

    Full Text Available Alkaline cellulase producing fungi were isolated from soils of an undisturbed rain forest of Peru. The soil dilution plate method was used for the enumeration and isolation of fast growing cellulolytic fungi on an enriched selective medium. Eleven out of 50 different morphological colonies were finally selected by using the plate clearing assay with CMC as substrate at different pH values. All 11 strains produced cellulases in liquid culture with activities at alkaline pH values without an apparent decrease of them indicating that they are true alkaline cellulase producers. Aspergillus sp. LM-HP32, Penicillium sp. LM-HP33, and Penicillium sp. LM-HP37 were the best producers of FP cellulase (>3 U mL−1 with higher specific productivities (>30 U g−1 h−1. Three strains have been found suitable for developing processes for alkaline cellulase production. Soils from Amazonian rain forests are good sources of industrial fungi with particular characteristics. The results of the present study are of commercial and biological interest. Alkaline cellulases may be used in the polishing and washing of denim processing of the textile industry.

  16. Leaf structural diversity is related to hydraulic capacity in tropical rain forest trees.

    Science.gov (United States)

    Sack, Lawren; Frole, Kristen

    2006-02-01

    The hydraulic resistance of the leaf (R1) is a major bottleneck in the whole plant water transport pathway and may thus be linked with the enormous variation in leaf structure and function among tropical rain forest trees. A previous study found that R1 varied by an order of magnitude across 10 tree species of Panamanian tropical lowland rain forest. Here, correlations were tested between R1 and 24 traits relating to leaf venation and mesophyll structure, and to gross leaf form. Across species, R1 was related to both venation architecture and mesophyll structure. R1 was positively related to the theoretical axial resistivity of the midrib, determined from xylem conduit numbers and dimensions, and R1 was negatively related to venation density in nine of 10 species. R1 was also negatively related to both palisade mesophyll thickness and to the ratio of palisade to spongy mesophyll. By contrast, numerous leaf traits were independent of R1, including area, shape, thickness, and density, demonstrating that leaves can be diverse in gross structure without intrinsic trade-offs in hydraulic capacity. Variation in both R1-linked and R1-independent traits related strongly to regeneration irradiance, indicating the potential importance of both types of traits in establishment ecology.

  17. Stem and leaf hydraulic properties are finely coordinated in three tropical rain forest tree species.

    Science.gov (United States)

    Nolf, Markus; Creek, Danielle; Duursma, Remko; Holtum, Joseph; Mayr, Stefan; Choat, Brendan

    2015-12-01

    Coordination of stem and leaf hydraulic traits allows terrestrial plants to maintain safe water status under limited water supply. Tropical rain forests, one of the world's most productive biomes, are vulnerable to drought and potentially threatened by increased aridity due to global climate change. However, the relationship of stem and leaf traits within the plant hydraulic continuum remains understudied, particularly in tropical species. We studied within-plant hydraulic coordination between stems and leaves in three tropical lowland rain forest tree species by analyses of hydraulic vulnerability [hydraulic methods and ultrasonic emission (UE) analysis], pressure-volume relations and in situ pre-dawn and midday water potentials (Ψ). We found finely coordinated stem and leaf hydraulic features, with a strategy of sacrificing leaves in favour of stems. Fifty percent of hydraulic conductivity (P50 ) was lost at -2.1 to -3.1 MPa in stems and at -1.7 to -2.2 MPa in leaves. UE analysis corresponded to hydraulic measurements. Safety margins (leaf P50 - stem P50 ) were very narrow at -0.4 to -1.4 MPa. Pressure-volume analysis and in situ Ψ indicated safe water status in stems but risk of hydraulic failure in leaves. Our study shows that stem and leaf hydraulics were finely tuned to avoid embolism formation in the xylem.

  18. Current and Future Carbon Budgets of Tropical Rain Forest: A Cross Scale Analysis. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Oberbauer, S. F.

    2004-01-16

    The goal of this project was to make a first assessment of the major carbon stocks and fluxes and their climatic determinants in a lowland neotropical rain forest, the La Selva Biological Station, Costa Rica. Our research design was based on the concurrent use of several of the best available approaches, so that data could be cross-validated. A major focus of our effort was to combine meteorological studies of whole-forest carbon exchange (eddy flux), with parallel independent measurements of key components of the forest carbon budget. The eddy flux system operated from February 1998 to February 2001. To obtain field data that could be scaled up to the landscape level, we monitored carbon stocks, net primary productivity components including tree growth and mortality, litterfall, woody debris production, root biomass, and soil respiration in a series of replicated plots stratified across the major environmental gradients of the forest. A second major focus of this project was on the stocks and changes of carbon in the soil. We used isotope studies and intensive monitoring to investigate soil organic stocks and the climate-driven variation of soil respiration down the soil profile, in a set of six 4m deep soil shafts stratified across the landscape. We measured short term tree growth, climate responses of sap flow, and phenology in a suite of ten canopy trees to develop individual models of tree growth to daytime weather variables.

  19. A preliminary study on the heat storage fluxes of a tropical seasonal rain forest in Xishuangbanna

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    <正>In order to discuss the values and daily variation characteristics of heat storage fluxes in a tropical seasonal rain forest in Xishuangbanna, the sensible and latent heat storage flux within air column, canopy heat storage flux, energy storage by photosynthesis and ground heat storage above the soil heat flux plate, as well as the ratios of these heat storage fluxes to the net radiation in the cool-dry, hot-dry and rainy season were compared and analyzed based on the observation data of carbon fluxes, meteorological factors and biomass within this tropical seasonal rain forest from January 2003 to December 2004. The findings showed that heat storage terms ranged significantly in the daytime and weakly in the nighttime, and the absolute values of sensible and latent heat storage fluxes were obviously greater than other heat storage terms in all seasons. In addition, the absolute values of total heat storage fluxes reached the peak in the hot-dry season, then were higher in the rainy season, and reached the minimum in the cool-dry season. The ratios of heat storage fluxes to net radiation generally decreased with time in the daytime, moreover, the sensible and latent heat storage dominated a considerable fraction of net radiation, while other heat storage contents occupied a smaller fraction of the net radiation and the peak value was not above 3.5%. In the daytime, the ratios of the total heat storage to net radiation were greater and differences in these ratios were distinct among seasons before 12:00, and then they became lower and differences were small among seasons after 12:00. The energy closure was improved when the storage terms were considered in the energy balance, which indicated that heat storage terms should not been neglected. The energy closure of tropical seasonal rain forest was not very well due to effects of many factors. The results would help us to further understand energy transfer and mass exchange between tropical forest and atmosphere

  20. Artificial canopy gaps and the establishment of planted dipterocarp seedlings in Macaranga spp. dominated secondary tropical rain forests of Sabah, Borneo

    OpenAIRE

    Romell, Eva

    2007-01-01

    The continued losses of primary tropical rain forests have increased the pressure on secondary tropical rain forests and led to additional logging and changes to other land uses. A requirement for a secondary tropical forest to recover the main traits of old-growth forests is the regeneration of non-pioneer (climax) species. To accelerate the recovery of non-pioneer species where natural regeneration is insufficient, enrichment planting can be used in artificially created gaps or lines. The s...

  1. Characterizing the phylogenetic tree community structure of a protected tropical rain forest area in Cameroon.

    Directory of Open Access Journals (Sweden)

    Stéphanie Manel

    Full Text Available Tropical rain forests, the richest terrestrial ecosystems in biodiversity on Earth are highly threatened by global changes. This paper aims to infer the mechanisms governing species tree assemblages by characterizing the phylogenetic structure of a tropical rain forest in a protected area of the Congo Basin, the Dja Faunal Reserve (Cameroon. We re-analyzed a dataset of 11538 individuals belonging to 372 taxa found along nine transects spanning five habitat types. We generated a dated phylogenetic tree including all sampled taxa to partition the phylogenetic diversity of the nine transects into alpha and beta components at the level of the transects and of the habitat types. The variation in phylogenetic composition among transects did not deviate from a random pattern at the scale of the Dja Faunal Reserve, probably due to a common history and weak environmental variation across the park. This lack of phylogenetic structure combined with an isolation-by-distance pattern of taxonomic diversity suggests that neutral dispersal limitation is a major driver of community assembly in the Dja. To assess any lack of sensitivity to the variation in habitat types, we restricted the analyses of transects to the terra firme primary forest and found results consistent with those of the whole dataset at the level of the transects. Additionally to previous analyses, we detected a weak but significant phylogenetic turnover among habitat types, suggesting that species sort in varying environments, even though it is not predominating on the overall phylogenetic structure. Finer analyses of clades indicated a signal of clustering for species from the Annonaceae family, while species from the Apocynaceae family indicated overdispersion. These results can contribute to the conservation of the park by improving our understanding of the processes dictating community assembly in these hyperdiverse but threatened regions of the world.

  2. Carbon budget of Nyungwe Tropical Montane Rain Forest in Central Africa

    Science.gov (United States)

    Nyirambangutse, B.; Zibera, E.; Uwizeye, F. K.; Hansson, L.; Nsabimana, D.; Pleijel, H.; Uddling, J.; Wallin, G.

    2015-12-01

    African tropical rainforests host rich biodiversity and play many roles at different scales such as local, regional and global, in the functioning of the earth system. Despite that the African tropical forests are the world's second largest, it has been neglected in terms of understanding the storage and fluxes of carbon and other nutrients. The question of whether this biome is a net sink or source of atmospheric CO2 is still not answered, and little is known concerning the climate change response. Tropical montane forests are even more poorly sampled compared with their importance. Deeper understanding of these ecosystems is required to provide insights on how they might react under global change. To answer questions related to these issues for African tropical montane forests, 15 permanent 0.5 ha plots were established in 2011 in Nyungwe tropical montane rainforest gazetted as a National Park to protect its extensive floral and faunal diversity. The plots are arranged along an east-westerly transect and includes both primary and secondary forest communities. The study is connected to the global ecosystem monitoring network (GEM, http://gem.tropicalforests.ox.ac.uk/). The aim is to characterize spatial and temporal heterogeneity of carbon and nutrient dynamics processes. The role of microclimate, topography, human disturbances, and plant species to the variability of these pools and processes will be explored. We compare stocks and fluxes of carbon and nutrients of the secondary and primary forest communities. The carbon stock are determined by an inventory of height and diameter at breast height (dbh) of all trees with a dbh above 5 cm, wood density, biomass of understory vegetation, leaf area index, standing and fallen dead wood, fine root biomass and organic content of various soil layers (litter, organic and mineral soil down to 45 cm depth). The carbon fluxes are determined by measurements of photosynthesis and respiration of leaves, above and below ground

  3. Mosquito (Diptera: Culicidae) diversity of a forest-fragment mosaic in the Amazon rain forest.

    Science.gov (United States)

    Hutchings, Rosa Sá Gomes; Sallum, Maria Anice Mureb; Hutchings, Roger William

    2011-03-01

    To study the impact of Amazonian forest fragmentation on the mosquito fauna, an inventory of Culicidae was conducted in the upland forest research areas of the Biological Dynamics of Forest Fragments Project located 60 km north of Manaus, Amazonas, Brazil. The culicid community was sampled monthly between February 2002 and May 2003. CDC light traps, flight interception traps, manual aspiration, and net sweeping were used to capture adult specimens along the edges and within forest fragments of different sizes (1, 10, and 100 ha), in second-growth areas surrounding the fragments and around camps. We collected 5,204 specimens, distributed in 18 genera and 160 species level taxa. A list of mosquito taxa is presented with 145 species found in the survey, including seven new records for Brazil, 16 new records for the state of Amazonas, along with the 15 morphotypes that probably represent undescribed species. No exotic species [Aedes aegypti (L.) and Aedes albopictus (Skuse)] were found within the sampled areas. Several species collected are potential vectors of Plasmodium causing human malaria and of various arboviruses. The epidemiological and ecological implications of mosquito species found are discussed, and the results are compared with other mosquito inventories from the Amazon region.

  4. Diameter Growth of Juvenile Trees after Gap Formation in a Bolivian Rain Forest: Responses are Strongly Species-specific and Size-dependent.

    NARCIS (Netherlands)

    Soliz-Gamboa, C.C.; Sandbrink, A.; Zuidema, P.A.

    2012-01-01

    We evaluated growth responses to gap formation for juvenile individuals of three canopy rain forest species: Peltogyne cf. heterophylla, Clarisia racemosa and Cedrelinga catenaeformis. Gaps were formed during selective logging operations 7 yr before sampling in a Bolivian rain forest. We collected w

  5. Tree fern trunks facilitate seedling regeneration in a productive lowland temperate rain forest.

    Science.gov (United States)

    Gaxiola, Aurora; Burrows, Larry E; Coomes, David A

    2008-03-01

    Seedling regeneration on forest floors is often impaired by competition with established plants. In some lowland temperate rain forests, tree fern trunks provide safe sites on which tree species establish, and grow large enough to take root in the ground and persist. Here we explore the competitive and facilitative effects of two tree fern species, Cyathea smithii and Dicksonia squarrosa, on the epiphytic regeneration of tree species in nutrient-rich alluvial forests in New Zealand. The difficulties that seedlings have in establishing on vertical tree fern trunks were indicated by the following observations. First, seedling abundance was greatest on the oldest sections of tree fern trunks, near the base, suggesting that trunks gradually recruited more and more seedlings over time, but many sections of trunk were devoid of seedlings, indicating the difficulty of establishment on a vertical surface. Second, most seedlings were from small-seeded species, presumably because smaller seeds can easily lodge on tree fern trunks. Deer browsing damage was observed on 73% of epiphytic seedlings growing within 2 m of the ground, whereas few seedlings above that height were browsed. This suggests that tree ferns provide refugia from introduced deer, and may slow the decline in population size of deer-preferred species. We reasoned that tree ferns would compete with epiphytic seedlings for light, because below the tree fern canopy photosynthetically active radiation (PAR) was about 1% of above-canopy PAR. Frond removal almost tripled %PAR on the forest floor, leading to a significant increase in the height growth rate (HGR) of seedlings planted on the forest floor, but having no effects on the HGRs of epiphytic seedlings. Our study shows evidence of direct facilitative interactions by tree ferns during seedling establishment in plant communities associated with nutrient-rich soils.

  6. Fungal community composition in neotropical rain forests: the influence of tree diversity and precipitation.

    Science.gov (United States)

    McGuire, Krista L; Fierer, Noah; Bateman, Carling; Treseder, Kathleen K; Turner, Benjamin L

    2012-05-01

    Plant diversity is considered one factor structuring soil fungal communities because the diversity of compounds in leaf litter might determine the extent of resource heterogeneity for decomposer communities. Lowland tropical rain forests have the highest plant diversity per area of any biome. Since fungi are responsible for much of the decomposition occurring in forest soils, understanding the factors that structure fungi in tropical forests may provide valuable insight for predicting changes in global carbon and nitrogen fluxes. To test the role of plant diversity in shaping fungal community structure and function, soil (0-20 cm) and leaf litter (O horizons) were collected from six established 1-ha forest census plots across a natural plant diversity gradient on the Isthmus of Panama. We used 454 pyrosequencing and phospholipid fatty acid analysis to evaluate correlations between microbial community composition, precipitation, soil nutrients, and plant richness. In soil, the number of fungal taxa increased significantly with increasing mean annual precipitation, but not with plant richness. There were no correlations between fungal communities in leaf litter and plant diversity or precipitation, and fungal communities were found to be compositionally distinct between soil and leaf litter. To directly test for effects of plant species richness on fungal diversity and function, we experimentally re-created litter diversity gradients in litter bags with 1, 25, and 50 species of litter. After 6 months, we found a significant effect of litter diversity on decomposition rate between one and 25 species of leaf litter. However, fungal richness did not track plant species richness. Although studies in a broader range of sites is required, these results suggest that precipitation may be a more important factor than plant diversity or soil nutrient status in structuring tropical forest soil fungal communities.

  7. Temperate pine barrens and tropical rain forests are both rich in undescribed fungi.

    Science.gov (United States)

    Luo, Jing; Walsh, Emily; Naik, Abhishek; Zhuang, Wenying; Zhang, Keqin; Cai, Lei; Zhang, Ning

    2014-01-01

    Most of fungal biodiversity on Earth remains unknown especially in the unexplored habitats. In this study, we compared fungi associated with grass (Poaceae) roots from two ecosystems: the temperate pine barrens in New Jersey, USA and tropical rain forests in Yunnan, China, using the same sampling, isolation and species identification methods. A total of 426 fungal isolates were obtained from 1600 root segments from 80 grass samples. Based on the internal transcribed spacer (ITS) sequences and morphological characteristics, a total of 85 fungal species (OTUs) belonging in 45 genera, 23 families, 16 orders, and 6 classes were identified, among which the pine barrens had 38 and Yunnan had 56 species, with only 9 species in common. The finding that grass roots in the tropical forests harbor higher fungal species diversity supports that tropical forests are fungal biodiversity hotspots. Sordariomycetes was dominant in both places but more Leotiomycetes were found in the pine barrens than Yunnan, which may play a role in the acidic and oligotrophic pine barrens ecosystem. Equal number of undescribed fungal species were discovered from the two sampled ecosystems, although the tropical Yunnan had more known fungal species. Pine barrens is a unique, unexplored ecosystem. Our finding suggests that sampling plants in such unexplored habitats will uncover novel fungi and that grass roots in pine barrens are one of the major reservoirs of novel fungi with about 47% being undescribed species.

  8. A Climate Change Threshold for Forest Dieback in the African Sahel

    Science.gov (United States)

    Gonzalez, P.; Tucker, C. J.; Sy, H.

    2007-12-01

    Increases in human greenhouse gas emissions to the atmosphere have increased global sea surface temperatures. Reinforced by a reduction in vegetation cover in the African Sahel, warmer sea surface temperatures have reduced rainfall in the Sahel by up to 30% in the 20th Century. In Senegal, annual precipitation fell to below one standard deviation of the 148 year mean for 5 years in the period 1968-1973. Although the region had experienced high historic variability in precipitation, the 1968-1973 drought crossed a climate threshold for agriculture that caused famine and human death. Sahel, Sudan, and Guinean ecosystems also crossed a climate threshold of aridity in an abrupt, nonlinear manner. The long-term decrease in precipitation caused extensive forest dieback and a latitudinal shift of the Sahel, Sudan, and Guinean ecological zones. The range of xeric forest species has expanded and mesic species have retracted southward towards areas of higher precipitation. Field inventories of tree species richness show declines in local biodiversity across the Sahel. Analyses of 1954 and 1989 aerial photographs and 2002 1-meter resolution IKONOS satellite images of three 200 km2 areas in Senegal and Mauritania also show declines in the density of trees of height > 3 m. Forest dieback fuels three positive feedback mechanisms: reduction of the evapotranspiration inputs necessary for the northward advance of the summer monsoon rains that sustain vegetation and forestall desertification, increases in the greenhouse gas emissions that cause the reduction in rainfall, and reduction of the forest biodiversity that strengthens ecosystem resilience to long-term drought. The interaction of climate change, desertification, and loss of biodiversity, as well as the complex social, economic, and political factors that lead to forest dieback and other ecological changes in the Sahel present difficulties in monitoring and foreseeing future threshold behavior. Nevertheless, any reduction in

  9. Towards ground-truthing of spaceborne estimates of above-ground biomass and leaf area index in tropical rain forests

    OpenAIRE

    Köhler, P.; Huth, A.

    2010-01-01

    The canopy height of forests is a key variable which can be obtained using air- or spaceborne remote sensing techniques such as radar interferometry or lidar. If new allometric relationships between canopy height and the biomass stored in the vegetation can be established this would offer the possibility for a global monitoring of the above-ground carbon content on land. In the absence of adequate field data we use simulation results of a tropical rain forest growth model to propose what degr...

  10. Multiple antibiotic resistant Escherichia coli from a tropical rain forest stream

    Energy Technology Data Exchange (ETDEWEB)

    Carrasco, C.E.; Alvarez, H.J.; Ortiz, N.; Bisbal, M.; Arias, W.; Baerga, C. [Univ. of Puerto Rico, Rio Piedras (Puerto Rico). Dept. of Biology; Hazen, T.C. [E.I. DuPont de Nemours and Co., Aiken, SC (United States). Savannah River Lab.

    1988-12-31

    High densities of fecal coliforms were obtained from a pristine site and sewage contaminated site in a tropical rain forest watershed in Puerto Rico. Confirmation of fecal coliform isolates as Escherichia coli was significantly lower than for temperate waters. Antibiotic resistance and multiple antibiotic resistance were common for isolates at both sites; however, the site receiving sewage effluent had a greater proportion of multiple antibiotic resistant isolates. R. plasmids were recovered from 4 MAR isolates, 2 from each site. All recovered plasmids were approximately 1 kilobase. The recovered plasmid were also capable of transforming E. coli HB101 in vitro. The high concentrations of enterobacteriaceae, small R-plasmid size, R-plasmid transformability, and long term survival of fecal origin bacteria in tropical freshwater environments give increasing importance to adequate sewage treatment, and better indicator monitoring methods for tropical areas.

  11. Assessment of organochlorine pesticide residues in Atlantic Rain Forest fragments, Rio de Janeiro, Brazil.

    Science.gov (United States)

    Quinete, Natalia Soares; de Oliveira, Elba dos Santos; Fernandes, Daniella R; Avelar, Andre de Souza; Santelli, Ricardo Erthal

    2011-12-01

    A superficial water quality survey in a watershed of the Paraíba do Sul River, the main water supply for the most populated cities of southeastern Brazil, was held in order to assess the impact of the expansion of agricultural activity in the near border of the Atlantic Rain Forest. The aim of this study was to investigate the presence of priority organochlorine pollutants in soils and superficial waters of Atlantic rainforest fragments in Teresópolis, Rio de Janeiro State. Soil sample preparations were compared by using ultrasound, microwave assisted extraction and Soxhlet extraction. Recoveries of matrix spiked samples ranged from 70 to 130%. Analysis of a certified soil material showed recoveries ranging from 71 to 234%. Although low concentrations of organochlorine residues were found in water and soil samples, this area is of environmental importance and concern, thus demanding a monitoring program of its compartments.

  12. Reproductive activity of ruffed lemurs (Varecia variegata variegata) in a Madagascar rain forest.

    Science.gov (United States)

    Morland, H S

    1993-05-01

    Mating activity was observed during four breeding seasons in two groups of black and white ruffed lemurs (Varecia variegata variegata) living in lowland rain forest on Nosy Mangabe island, Madagascar. The onset of the May-July breeding season was signalled by behavioral changes in adult males. Males made forays outside their usual home ranges, were more aggressive to other males, and performed appetitive and other sex-specific behaviors more frequently. Females showed receptive and proceptive behaviors during a 1-2 day behavioral estrus. Ruffed lemurs mated monogamously, polyandrously, and polygynously. These observations do not support previous assertions that they live only in monogamous families. Limited evidence suggests females exercised mate choice and may have preferred familiar males.

  13. Yeast communities in two Atlantic rain Forest fragments in Southeast Brazil

    Science.gov (United States)

    Pimenta, Raphael S.; Alves, Priscila D. D.; Almeida, Gabriel M. F.; Silva, Juliana F.M; Morais, Paula B.; Corrêa Jr., Ary; Rosa, Carlos A.

    2009-01-01

    We studied the yeast communities associated with fruits, mushrooms, tree exudates, and flies of the genus Drosophila, in two Atlantic Rain Forest fragments in state of Minas Gerais, Brazil. A total of 456 samples were collected from Rio Doce State Park and 142 from Ecological Station of Universidade Federal de Minas Gerais. From these samples, 608 yeast isolates were obtained, belonging to 71 different species. Among the yeasts isolated from Rio Doce State Park, 17 isolates were recovered from fruits, 12 from mushrooms, 13 from tree exudates, and 299 from Drosophila spp. In the Ecological Station of Universidade Federal de Minas Gerais, 24 isolates were recovered from fruits and 243 from Drosophila spp. Distinct communities of yeast were observed in Drosophila flies, fruits, mushrooms and tree exudates. The highest number of yeast species was recovered from Drosophila flies suggesting that flies are the natural vectors of these microorganisms. PMID:24031324

  14. Soil and light effects on the sapling performance of a shade-tolerant tree species in a Mexican rain forest

    NARCIS (Netherlands)

    Lopez, L.; Martinez, M.; Breugel, van M.; Sterck, F.J.

    2008-01-01

    Many studies conclude that light is the most important resource that determines plant performance of tree saplings in tropical rain forests, and implicitly suggest that soil resources are less important. To provide a quantitative test for soil versus light effects on sapling performance, we studied

  15. Los Arboles Hablan: A Spanish Language Curriculum Unit Based on the Study of Latin American Rain Forests.

    Science.gov (United States)

    Zuman, John P.

    "Los Arboles Hablan," a video-based curriculum that promotes the learning of Spanish as a second language through study of the Latin American rain forests is described. The 12-session unit was designed for use at the middle school level and integrates science, social science, and environmental education with content focusing on the…

  16. Vegetation composition and altitudinal distribution of Andean rain forests in El Angel and Guandera reserves, northern Ecuador

    NARCIS (Netherlands)

    Moscol Olivera, M.C.; Cleef, A.M.

    2009-01-01

    Patterns of vascular plant species composition and structure of the remaining rain forest of the Andean Cordillera in northern Ecuador were studied in two reserves: Guandera and El Angel. Thirty three plots located between 3300 and 3700 in were examined along two altitudinal transects crossing the U

  17. Trees and light; Tree development and morphology in relation to light availability in a tropical rain forest in French Guiana.

    NARCIS (Netherlands)

    Sterck, F.J.

    1997-01-01

    Tropical rain forest trees spend their life in a heterogeneous light environment. During their life history, they may change their growth in relation to different levels of light availability. Some of their physiological processes (e.g. photosynthesis, carbon allocation, and meristern activity) chan

  18. Complementary resource use by tree species in a rain forest tree plantation.

    Science.gov (United States)

    Richards, Anna E; Schmidt, Susanne

    2010-07-01

    Mixed-species tree plantations, composed of high-value native rain forest timbers, are potential forestry systems for the subtropics and tropics that can provide ecological and production benefits. Choices of rain forest tree species for mixtures are generally based on the concept that assemblages of fast-growing and light-demanding species are less productive than assemblages of species with different shade tolerances. We examined the hypothesis that mixtures of two fast-growing species compete for resources, while mixtures of shade-tolerant and shade-intolerant species are complementary. Ecophysiological characteristics of young trees were determined and analyzed with a physiology-based canopy model (MAESTRA) to test species interactions. Contrary to predictions, there was evidence for complementary interactions between two fast-growing species with respect to nutrient uptake, nutrient use efficiency, and nutrient cycling. Fast-growing Elaeocarpus angustifolius had maximum demand for soil nutrients in summer, the most efficient internal recycling of N, and low P use efficiency at the leaf and whole-plant level and produced a large amount of nutrient-rich litter. In contrast, fast-growing Grevillea robusta had maximum demand for soil nutrients in spring and highest leaf nutrient use efficiency for N and P and produced low-nutrient litter. Thus, mixtures of fast-growing G. robusta and E. angustifolius or G. robusta and slow-growing, shade-tolerant Castanospermum australe may have similar or even greater productivity than monocultures, as light requirement is just one of several factors affecting performance of mixed-species plantations. We conclude that the knowledge gained here will be useful for designing large-scale experimental mixtures and commercial forestry systems in subtropical Australia and elsewhere.

  19. Effects on watershed hydrology after rain forest conversion to shifting cultivation and agroforestry in Sabah, Malaysia

    Energy Technology Data Exchange (ETDEWEB)

    Fagerberg, Nils

    1998-12-31

    A paired catchment study was conducted in Mendolong, Sabah, Malaysia, to monitor the hydrological effects from conversion of secondary rain forest to shifting cultivation and agroforestry land-uses. Four different treatments were investigated: (1.) Agroforestry with initial burning and planting of fast-growing trees (Acacia mangium) and one rotation of hill rice, (2.) Agroforestry treatment as in no. 1, but without burning, (3.) Shifting cultivation with burning and one rotation of hill rice and (4.) No burning and one rotation of hill rice. A fifth catchment was used as untreated control. Waterflow was continuously measured in the streams during 41 months, between May 1994 to November 1997. 11 months were used as a calibration period before clear-felling and treatments. The data were used to determine water budgets (precipitation, runoff and evapotranspiration), runoff increases after clear-felling and changes in streamflow regimes. Regression analyses on runoff from each catchment versus the control catchment during the calibration period were used to determine the increase in runoff after clear-felling. Some unexpected losses and gains of water across the borders of the divided catchments were detected in three of the five catchments. The estimated transferred water volumes under forest cover range between 10 % and 22 % of total runoff. After clear-felling the losses and gains of water across the borders increased. The water transfer did mainly occur as sub-surface flow, probably in more permeable parts in the lower soil profile like cracks in the bedrock. Generally, the risk of deep leakage seams to increase with distance from the ridge. Hydrological effects could still be calculated through amalgamation of two of the catchments, and since the third catchment had a stable level of water gain due to unchanged conditions in the surrounding catchments. The mean areal rainfall during the period was higher than earlier measurements in the area, 4061 mm. The mean

  20. OH observations in a tropical rain forest environment using a chemical ionization mass spectrometry technique during GOAmazon intensive campaigns

    Science.gov (United States)

    Kim, S.; Seco, R.; Park, J. H.; Sjostedt, S. J.; Guenther, A. B.; Smith, J. N.; Liu, Y.; Bustillos, J. O. V.; Souza, R. A. F. D.; Tota, J.; Martin, S. T.

    2015-12-01

    We will present observed OH in the Amazon rain forest using a chemical ionization mass spectrometer (CIMS). The observation was conducted at the T3 site in Manacapuru, Amazonas Brazil. It had been accepted almost as an axiom that very low OH is expected in low NO environments such as a pristine rain forest. However, recent studies in the pristine rain forest environments consistently reported significantly higher than expected OH levels. This sparked extensive and intensive studies to explore any possibility of OH regeneration from isoprene photo-oxidation processes in the low NO condition. Four OH regeneration processes related with isoprene photochemistry have been proposed since 2008. However, the levels of the expected OH enhancement vary greatly among the proposed OH regeneration processes mediated by the isoprene oxidation processes. As all enhanced OH observations from the pristine areas with high isoprene conditions have used the laser induced fluorescence (LIF) technique, the possibilities of potential positive artifacts have also been explored. In this context, the first tropical forest CIMS OH dataset will be discussed in the context of 1) comparisons with previously reported OH using the LIF technique, 2) comparisons with box model calculated OH with different isoprene oxidation scenarios to reconcile measured and calculated OH, and 3) comparisons with regional model calculated OH. The CIMS observational dataset along with a comprehensive trace gas dataset provides a constraint to assess current uncertainty in oxidation capacity of the pristine forested region, which has tremendous implications towards global fates of short lived climate forcers.

  1. [Relationships between soil moisture and needle-fall in Masson pine forests in acid rain region of Chongqing, Southwest China].

    Science.gov (United States)

    Wang, Yi-Hao; Wang, Yan-Hui; Li, Zhen-Hua; Yu, Peng-Tao; Xiong, Wei; Hao, Jia; Duan, Jian

    2012-10-01

    From March 2009 to November 2011, an investigation was conducted on the spatiotemporal variation of soil moisture and its effects on the needle-fall in Masson pine (Pinus massoniana) forests in acid rain region of Chongqing, Southeast China, with the corresponding soil moisture thresholds determined. No matter the annual precipitation was abundant, normal or less than average, the seasonal variation of soil moisture in the forests could be obviously divided into four periods, i.e., sufficient (before May), descending (from June to July), drought (from August to September), and recovering (from October to November). With increasing soil depth, the soil moisture content increased after an initial decrease, but the difference of the soil moisture content among different soil layers decreased with decreasing annual precipitation. The amount of monthly needle-fall in the forests in growth season was significantly correlated with the water storage in root zone (0-60 cm soil layer), especially in the main root zone (20-50 cm soil layer). Soil field capacity (or capillary porosity) and 82% of field capacity (or 80% of capillary porosity) were the main soil moisture thresholds affecting the litter-fall. It was suggested that in acid rain region, Masson pine forest was easily to suffer from water deficit stress, especially in dry-summer period. The water deficit stress, together with already existed acid rain stress, would further threaten the health of the Masson forest.

  2. 5 Floristics and structure of a Mixed Rain Forest remnant on the Catarinense Plateau

    Directory of Open Access Journals (Sweden)

    Carine Klauberg

    2010-03-01

    Full Text Available The objective of this study was to describe the floristics and the structure of tree species in the Parque Municipal Natural of Lages, SC, a remnant of mixed rain forest located in southern Brazil. For this, we allocated four plots (40 x 40m and each plot was divided into 16 sub-plots of 10 x 10m. Trees with dbh ≥ 5cm and height ≥ 1.3m were mapped, tagged and measured. The individuals were identified and voucher material was deposited in the herbarium. A total of 46 species were sampled, distributed in 39 genera and 27 families. The richest families in number of species were Myrtaceae, Lauraceae, Salicaceae and Sapindaceae. Seven species represented more than 60% of the total of individuals. The specific diversity was H’ = 3.05 nats.ind-1 (J’ = 0.81. The similarity among plots was 32 at 44%, indicating low similarity among plots. The spatial distribution of most of the species is classified as clumped, according to the Morisita index. This forest remains with a considerable richness and diversity with some endangered tree species such as Araucaria angustifolia and Dicksonia sellowiana. Due to its ecological importance for the local flora and fauna and the fragmentation process in the region, this remnant should be considered as a priority area for conservation.

  3. Grassland Species Collected in an Area of the Amazon Dense Rain Forest Southern

    Directory of Open Access Journals (Sweden)

    J. M. P. Florentino

    2013-07-01

    Full Text Available Abstract: The knowledge related to floristic composition and all strata, including herbaceous, are needed to characterize and understand the dynamics of tropical forests. This study aimed to investigate the floristic composition of herbs in an area of ??tropical rain forest of Mato Grosso, producing a list of herbaceous species are on site. All individuals and herbaceous hemiepiphytes above 5 cm were recorded. Inventoried 7,965 individuals, representing 70 species. The angiosperms were represented by 10 families, with the most representative families in number of species Cyperaceae and Poaceae. Ferns were represented by 13 families, the family Pteridaceae as the richest in species. These results reinforce the need to increase the sampling effort for the herbaceous layer, especially floristic surveys for Southern Amazon as of 70 species inventoried 11espies not have records for the state of Mato Grosso. The Amazon of Mato Grosso suffers severe pressure from deforestation, as part of the region known as the Arc of Deforestation. This fact combined with the results of this work shows the urgency to intensify the sampling effort in this region that presents itself as a void in terms of surveys of plant diversity.Keywords: floristic composition, plant diversity, ferns

  4. Multiresolution quantification of deciduousness in West Central African forests

    Directory of Open Access Journals (Sweden)

    G. Viennois

    2013-04-01

    Full Text Available The characterization of leaf phenology in tropical forests is of major importance and improves our understanding of earth-atmosphere-climate interactions. The availability of satellite optical data with a high temporal resolution has permitted the identification of unexpected phenological cycles, particularly over the Amazon region. A primary issue in these studies is the relationship between the optical reflectance of pixels of 1 km or more in size and ground information of limited spatial extent. In this paper, we demonstrate that optical data with high to very-high spatial resolution can help bridge this scale gap by providing snapshots of the canopy that allow discernment of the leaf-phenological stage of trees and the proportions of leaved crowns within the canopy. We also propose applications for broad-scale forest characterization and mapping in West Central Africa over an area of 141 000 km2. Eleven years of the Moderate Resolution Imaging Spectroradiometer (MODIS Enhanced Vegetation Index (EVI data were averaged over the wet and dry seasons to provide a dataset of optimal radiometric quality at a spatial resolution of 250 m. Sample areas covered at a very-high (GeoEye and high (SPOT-5 spatial resolution were used to identify forest types and to quantify the proportion of leaved trees in the canopy. The dry season EVI was positively correlated with the proportion of leaved trees in the canopy. This relationship allowed the conversion of EVI into canopy deciduousness at the regional level. On this basis, ecologically important forest types could be mapped, including young secondary, open Marantaceae, Gilbertiodendron dewevrei and swamp forests. We show that in west central African forests, a large share of the variability in canopy reflectance, as captured by the EVI, is due to variation in the proportion of leaved trees in the upper canopy, thereby opening new perspectives for biodiversity and carbon-cycle applications.

  5. A comparison of dry and wet season aerosol number fluxes over the Amazon rain forest

    Directory of Open Access Journals (Sweden)

    L. Ahlm

    2010-03-01

    Full Text Available Vertical number fluxes of aerosol particles and vertical fluxes of CO2 were measured with the eddy covariance method at the top of a 53 m high tower in the Amazon rain forest as part of the LBA (The Large Scale Biosphere Atmosphere Experiment in Amazonia experiment. The observed aerosol number fluxes included particles with sizes down to 10 nm in diameter. The measurements were carried out during the wet and dry season in 2008. In this study focus is on the dry season aerosol fluxes, with significant influence from biomass burning, and these are compared with aerosol fluxes measured during the wet season.

    Net particle deposition fluxes dominated in daytime in both seasons and the deposition flux was considerably larger in the dry season due to the much higher dry season particle concentration. The particle transfer velocity increased linearly with increasing friction velocity in both seasons. The difference in transfer velocity between the two seasons was small, indicating that the seasonal change in aerosol number size distribution is not enough for causing any significant change in deposition velocity. In general, particle transfer velocities in this study are low compared to studies over boreal forests. The reasons are probably the high percentage of accumulation mode particles and the low percentage of nucleation mode particles in the Amazon boundary layer, both in the dry and wet season, and low wind speeds in the tropics compared to the midlatitudes.

    In the dry season, nocturnal particle fluxes behaved very similar to the nocturnal CO2 fluxes. Throughout the night, the measured particle flux at the top of the tower was close to zero, but early in the morning there was an upward particle flux peak that is not likely a result of entrainment or local pollution. It is possible that these morning upward particle fluxes are associated with emission of primary biogenic particles from the rain forest

  6. Aerosol number fluxes over the Amazon rain forest during the wet season

    Directory of Open Access Journals (Sweden)

    L. Ahlm

    2009-08-01

    Full Text Available Number fluxes of particles with diameter larger than 10 nm were measured with the eddy covariance method over the Amazon rain forest during the wet season as part of the LBA (The Large Scale Biosphere Atmosphere Experiment in Amazonia campaign 2008. The primary goal was to investigate whether sources or sinks dominate the aerosol number flux in the tropical rain forest-atmosphere system.

    During the measurement campaign, from 12 March to 18 May, 60% of the particle fluxes pointed downward, which is a similar fraction to what has been observed over boreal forests. The particle transfer velocity vt increased with increasing friction velocity and the relation is described by the equation vt=2.4×10−3·u where u is the friction velocity.

    Upward particle fluxes often appeared in the morning hours and seem to a large extent to be an effect of entrainment fluxes into a growing mixed layer rather than primary aerosol emission. In general, primary aerosol emission had a limited impact on the total aerosol number population in this study, possibly because the measured particle number fluxes reflect mostly particles less than approximately 200 nm.

    The net deposition flux prevailed even in the absolute cleanest atmospheric conditions during the campaign and therefore cannot be explained only by deposition of anthropogenic particles. It seems that a significant contribution of secondary aerosol particles to the aerosol population is the most reasonable explanation for the net downward flux. This is an indication that secondary aerosol particles may dominate the aerosol number population in the Amazon boundary layer and that the contribution of primary aerosol particles may be low in terms of numbers. However, aerosol flux measurements should be repeated in a more remote area of the Amazon with less influence from anthropogenic sources before

  7. Control over ecosystem CO2 exchange by winter snow versus summer rain in a subalpine coniferous forest

    Science.gov (United States)

    Monson, R. K.; Moore, D. J.; Scott-Denton, L.; Rosenbloom, N.; Kittel, T.

    2008-12-01

    Subalpine forests in the Western U.S. depend on both winter snow and summer rain to provide water. Recent observations have shown a widespread decline in the snowpack of mountain ecosystems in the Western U.S. that is coupled to wintertime high temperature anomalies. Twenty-one coupled GCM models have predicted that this trend will continue. These same models predict changes in the summer precipitation regime, though with less consistency. In order to better understand the partitioning of soil water between winter snow and summer rain, we have been studying the seasonal 2H/1H signatures of these two water sources, as well as stem water (expressed as δD, or delta deuterium). Our analysis revealed that all three dominant tree species (spruce, pine and fir) relied on snowmelt water, to a varying extent, for the entire season. By mid-summer, however, the average contribution of rain water to tree xylem water had increased. We used the isotopic data of seasonal trends in water use to parameterize the SIPNET ecosystem process model. Using the model, we predicted that during warmer years the forest will more water stress with concomitantly lower midsummer photosynthesis rates. Given future climate projections for the Colorado Front Range of the Rocky Mountains, with associated earlier spring snow melt and reduced spring snowpacks, our analysis revealed that there will likely be more reliance on summer rains for CO2 uptake by Rocky Mountain subalpine forests.

  8. Optimal Wavelength Selection on Hyperspectral Data with Fused Lasso for Biomass Estimation of Tropical Rain Forest

    Science.gov (United States)

    Takayama, T.; Iwasaki, A.

    2016-06-01

    Above-ground biomass prediction of tropical rain forest using remote sensing data is of paramount importance to continuous large-area forest monitoring. Hyperspectral data can provide rich spectral information for the biomass prediction; however, the prediction accuracy is affected by a small-sample-size problem, which widely exists as overfitting in using high dimensional data where the number of training samples is smaller than the dimensionality of the samples due to limitation of require time, cost, and human resources for field surveys. A common approach to addressing this problem is reducing the dimensionality of dataset. Also, acquired hyperspectral data usually have low signal-to-noise ratio due to a narrow bandwidth and local or global shifts of peaks due to instrumental instability or small differences in considering practical measurement conditions. In this work, we propose a methodology based on fused lasso regression that select optimal bands for the biomass prediction model with encouraging sparsity and grouping, which solves the small-sample-size problem by the dimensionality reduction from the sparsity and the noise and peak shift problem by the grouping. The prediction model provided higher accuracy with root-mean-square error (RMSE) of 66.16 t/ha in the cross-validation than other methods; multiple linear analysis, partial least squares regression, and lasso regression. Furthermore, fusion of spectral and spatial information derived from texture index increased the prediction accuracy with RMSE of 62.62 t/ha. This analysis proves efficiency of fused lasso and image texture in biomass estimation of tropical forests.

  9. OPTIMAL WAVELENGTH SELECTION ON HYPERSPECTRAL DATA WITH FUSED LASSO FOR BIOMASS ESTIMATION OF TROPICAL RAIN FOREST

    Directory of Open Access Journals (Sweden)

    T. Takayama

    2016-06-01

    Full Text Available Above-ground biomass prediction of tropical rain forest using remote sensing data is of paramount importance to continuous large-area forest monitoring. Hyperspectral data can provide rich spectral information for the biomass prediction; however, the prediction accuracy is affected by a small-sample-size problem, which widely exists as overfitting in using high dimensional data where the number of training samples is smaller than the dimensionality of the samples due to limitation of require time, cost, and human resources for field surveys. A common approach to addressing this problem is reducing the dimensionality of dataset. Also, acquired hyperspectral data usually have low signal-to-noise ratio due to a narrow bandwidth and local or global shifts of peaks due to instrumental instability or small differences in considering practical measurement conditions. In this work, we propose a methodology based on fused lasso regression that select optimal bands for the biomass prediction model with encouraging sparsity and grouping, which solves the small-sample-size problem by the dimensionality reduction from the sparsity and the noise and peak shift problem by the grouping. The prediction model provided higher accuracy with root-mean-square error (RMSE of 66.16 t/ha in the cross-validation than other methods; multiple linear analysis, partial least squares regression, and lasso regression. Furthermore, fusion of spectral and spatial information derived from texture index increased the prediction accuracy with RMSE of 62.62 t/ha. This analysis proves efficiency of fused lasso and image texture in biomass estimation of tropical forests.

  10. Ecosystem Respiration in an Undisturbed, Old-Growth, Temperate Rain Forest

    Science.gov (United States)

    Hunt, J. E.; Walcroft, A. S.; McSeveny, T. M.; Rogers, G. N.; Whitehead, D.

    2008-12-01

    Old-growth forests are usually close to carbon neutral, and climate change may push them towards becoming net carbon sources. Ecosystem carbon exchange and its component fluxes, were measured in a temperate rainforest in South Westland, New Zealand. The forest, which receives over 3 m of rain a year, is dominated by 400 year-old podocarp trees, and is on a low nutrient, acidic, peat soil. Nighttime respiration measurements using eddy covariance were problematic due to katabatic induced CO2 drainage flows near the ground and low turbulence. Instead of the friction velocity filtering technique, we used the maximum eddy flux within a few hours of sunset to derive a function relating nighttime ecosystem respiration to soil temperature. The function was then used to calculate respiration for the nighttime periods. Soil respiration was measured at regular intervals during the growing season. Soil temperature was regulated by incoming radiation and changes in the soil heat capacity. The water table was typically only 160 mm below the ground surface. Soil respiration (mean = 2.9 μmol m-2 s-1) increased strongly with both an increase in soil temperature and an increase in the depth to the water table, and accounted for approximately 50% of ecosystem respiration. Changes in the water table depth caused by altered rainfall regime, evaporation and drainage are likely to have a significant effect on the soil respiration rate and carbon balance of this old-growth forest. Foliage and stem respiration were also measured and integrated to the canopy scale using a model. The model was then used to decompose ecosystem respiration measurements into its components. A combination of measured and modelled data indicates that the ecosystem is a net source for carbon (-0.34 kg C m&-2 yr-1).

  11. Aboveground and belowground effects of single-tree removals in New Zealand rain forest.

    Science.gov (United States)

    Wardle, David A; Wiser, Susan K; Allen, Robert B; Doherty, James E; Bonner, Karen I; Williamson, Wendy M

    2008-05-01

    There has been considerable recent interest in how human-induced species loss affects community and ecosystem properties. These effects are particularly apparent when a commercially valuable species is harvested from an ecosystem, such as occurs through single-tree harvesting or selective logging of desired timber species in natural forests. In New Zealand mixed-species rain forests, single-tree harvesting of the emergent gymnosperm Dacrydium cupressinum, or rimu, has been widespread. This harvesting has been contentious in part because of possible ecological impacts of Dacrydium removal on the remainder of the forest, but many of these effects remain unexplored. We identified an area where an unintended 40-year "removal experiment" had been set up that involved selective extraction of individual Dacrydium trees. We measured aboveground and belowground variables at set distances from both individual live trees and stumps of trees harvested 40 years ago. Live trees had effects both above and below ground by affecting diversity and cover of several components of the vegetation (usually negatively), promoting soil C sequestration, enhancing ratios of soil C:P and N:P, and affecting community structure of soil microflora. These effects extended to 8 m from the tree base and were likely caused by poor-quality litter and humus produced by the trees. Measurements for the stumps revealed strong legacy effects of prior presence of trees on some properties (e.g., cover by understory herbs and ferns, soil C sequestration, soil C:P and N:P ratios), but not others (e.g., soil fungal biomass, soil N concentration). These results suggest that the legacy of prior presence of Dacrydium may remain for several decades or centuries, and certainly well over 40 years. They also demonstrate that, while large Dacrydium individuals (and their removal) may have important effects in their immediate proximity, within a forest, these effects should only be important in localized patches

  12. Dispersal of Culex quinquefasciatus (Diptera: Culicidae) in a Hawaiian rain forest

    Science.gov (United States)

    Lapointe, D.A.

    2008-01-01

    Introduced mosquito-borne pathogens avian malaria (Plasmodium relictum Grassi and Feletti) and avian pox virus (Avipoxvirus) have been implicated in the past extinctions and declines of Hawaiian avifauna and remain significant obstacles to the recovery and restoration of endemic Hawaiian birds. Effective management of avian disease will require extensive mosquito control efforts that are guided by the local ecology of the vector Culex quinquefasciatus Say (Diptera: Culicidae). During October and November 1997 and September through November 1998 five mark-release-recapture experiments with laboratory-reared Cx. quinquefasciatus were conducted in a native rain forest on Hawaii Island. Of the overall 66,047 fluorescent dye-marked and released females, 1,192 (1.8%) were recaptured in 43-52 CO2-baited traps operated for 10-12-d trapping periods. Recaptured mosquitoes were trapped in all directions and at distances up to 3 km from the release site. The cumulative mean distance traveled (MDTs) over the trapping period ranged from a high of 1.89 km after 11 d (September 1998) to a low of 0.81 km after 11 d (November 1998). Released mosquitoes moved predominately in a downwind direction and they seemed to use forestry roads as dispersal corridors. Applying an estimated MDT of 1.6 km to a geographical information system-generated map of the Hakalau Forest National Wildlife Refuge clearly demonstrated that the effective refuge area could be reduced 60% by mosquitoes infiltrating into managed refuge lands. These findings should have significant implications for the design of future refuges and development of effective mosquito-borne avian disease control strategies.

  13. Interspecific variation of photosynthesis and leaf characteristics in canopy trees of five species of Dipterocarpaceae in a tropical rain forest.

    Science.gov (United States)

    Kenzo, Tanaka; Ichie, Tomoaki; Yoneda, Reiji; Kitahashi, Yoshinori; Watanabe, Yoko; Ninomiya, Ikuo; Koike, Takayoshi

    2004-10-01

    Photosynthetic rate, nitrogen concentration and morphological properties of canopy leaves were studied in 18 trees, comprising five dipterocarp species, in a tropical rain forest in Sarawak, Malaysia. Photosynthetic rate at light saturation (Pmax) differed significantly across species, varying from 7 to 18 micro mol m(-2) s(-1). Leaf nitrogen concentration and morphological properties, such as leaf blade and palisade layer thickness, leaf mass per area (LMA) and surface area of mesophyll cells per unit leaf area (Ames/A), also varied significantly across species. Among the relationships with leaf characteristics, Pmax had the strongest correlation with leaf mesophyll parameters, such as palisade cell layer thickness (r2 = 0.76, P palisade layer, with up to five or more layers. We conclude that interspecific variation in photosynthetic capacity in tropical rain forest canopies is influenced more by leaf mesophyll structure than by leaf thickness, LMA or leaf nitrogen concentration.

  14. Singing in the rain forest: how a tropical bird song transfers information.

    Directory of Open Access Journals (Sweden)

    Nicolas Mathevon

    Full Text Available How information transmission processes between individuals are shaped by natural selection is a key question for the understanding of the evolution of acoustic communication systems. Environmental acoustics predict that signal structure will differ depending on general features of the habitat. Social features, like individual spacing and mating behavior, may also be important for the design of communication. Here we present the first experimental study investigating how a tropical rainforest bird, the white-browed warbler Basileuterus leucoblepharus, extracts various information from a received song: species-specific identity, individual identity and location of the sender. Species-specific information is encoded in a resistant acoustic feature and is thus a public signal helping males to reach a wide audience. Conversely, individual identity is supported by song features susceptible to propagation: this private signal is reserved for neighbors. Finally, the receivers can locate the singers by using propagation-induced song modifications. Thus, this communication system is well matched to the acoustic constraints of the rain forest and to the ecological requirements of the species. Our results emphasize that, in a constraining acoustic environment, the efficiency of a sound communication system results from a coding/decoding process particularly well tuned to the acoustic properties of this environment.

  15. Genetic structure and conservation of Mountain Lions in the South-Brazilian Atlantic Rain Forest

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    Camila S. Castilho

    2012-01-01

    Full Text Available The Brazilian Atlantic Rain Forest, one of the most endangered ecosystems worldwide, is also among the most important hotspots as regards biodiversity. Through intensive logging, the initial area has been reduced to around 12% of its original size. In this study we investigated the genetic variability and structure of the mountain lion, Puma concolor. Using 18 microsatellite loci we analyzed evidence of allele dropout, null alleles and stuttering, calculated the number of allele/locus, PIC, observed and expected heterozygosity, linkage disequilibrium, Hardy-Weinberg equilibrium, F IS, effective population size and genetic structure (MICROCHECKER, CERVUS, GENEPOP, FSTAT, ARLEQUIN, ONESAMP, LDNe, PCAGEN, GENECLASS software,we also determine whether there was evidence of a bottleneck (HYBRIDLAB, BOTTLENECK software that might influence the future viability of the population in south Brazil. 106 alleles were identified, with the number of alleles/locus ranging from 2 to 11. Mean observed heterozygosity, mean number of alleles and polymorphism information content were 0.609, 5.89, and 0.6255, respectively. This population presented evidence of a recent bottleneck and loss of genetic variation. Persistent regional poaching constitutes an increasing in the extinction risk.

  16. Snaring to control feral pigs sus scrofa in a remote Hawaiian rain forest

    Science.gov (United States)

    Anderson, Stephen J.; Stone, Charles P.

    1993-01-01

    Feral pig Sus scrofa control in Kipahulu Valley, a remote rain forest in Haleakala National Park, Maui, Hawaiian Islands, has been achieved with snares over a 45-month period. Initial pig densities in fenced management units of 6·2 km2 and 7·8 km2were estimated at 6 animals/km2 and 14·3 animals/km2 for the two units, based on population reconstruction from animals killed and aged. During the 45 months of the study, 1978 snares were set, and 1·6 million snare nights were logged. Snare density reached 96/km2 and 200/km2 for the two management units by the end of the study. A mean effort of 43 worker hours/pig was used to remove 53 pigs from the upper management unit, and a mean of 7 worker hours/pig to remove 175 animals from the more densely populated lower unit. Pig activity monitoring along transects provided a good measure of control effectiveness until densities of about 1 pig/km2 were achieved, after which transects became less useful than scouting for determining pig activity.

  17. Survival and distribution of Vibrio cholerae in a tropical rain forest stream

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Rosas, N. [Univ. of Puerto Rico, Rio Piedras (Puerto Rico). Microbial Ecology Lab.; Hazen, T.C. [E.I. DuPont de Nemours and Co., Aiken, SC (United States). Savannah River Lab.

    1988-12-31

    For 12 months Vibrio cholerae and fecal coliforms were monitored along with 9 other water quality parameters at 12 sites in a rain forest watershed in Puerto Rico. Densities of V. cholerae and fecal coliforms were not significantly correlated even though the highest densities of both bacteria were found at a sewage outfall. High densities of V. cholerae were also found at pristine sites high in the watershed. V. cholerae and Escherichia coli were inoculated into membrane diffusion chambers, placed at two sites and monitored for 5 days on two different occasions. Two different direct count methods indicated that the density of E. coli and V. cholerae did not change significantly during the course of either study. Physiological activity, as measured by INT-reduction and relative nucleic acid composition declined for E. coli during the first 12 h then increased and remained variable during the remainder of the study. V. cholerae activity, as measured by relative nucleic acid concentrations, remained high and unchanged for the entire study. INT-reduction in V. cholerae declined initially but regained nearly all of it`s original activity within 48 h. This study suggests that V. cholerae is an indigenous organism in tropical freshwaters and that assays other than fecal coliforms or E. coli must be used for assessing public health risk in tropical waters.

  18. Species association in tropical montane rain forest at two successional stages in Diaoluo Mountain, Hainan

    Institute of Scientific and Technical Information of China (English)

    Fude LIU; Wenjin WANG; Ming ZHANG; Jianwei ZHENG; Zhongsheng WANG; Shiting ZHANG; Wenjie YANG; Shuqing AN

    2008-01-01

    Species association is one of the basic concepts in community succession. There are different viewpoints on how species interaction changes with the progress of succession. In order to assess these relationships, we examined species associations in the tropical montane rain forest at early and late successional stages in Diaoluo Mountain, Hainan Island. Based on data from a 2 × 2 contingency table of species presence or absence, statist-ical methods including analysis of species association and χ2 tests were applied. The results show that: 1) an overall positive association was present among tree species in the communities during the two successional stages and were statistically significant at the late stage. The number of species pairs with positive and negative associations decreased throughout the process of succession, while the number with null associations was greatly increased. The same trend existed among the dominant and compan-ion species. The results indicate that the communities are developing towards a stable stage where the woody species coexist in harmony. 2) In the early-established and later invading species, all positive associations were not signifi-cant. Compared with positive and null associations, fewer negative associations were found. This implies that these species are inclined to coexist independently through por-tioning of resources. 3) Among the later invading species, positive associations were significant and no negative associations were found which suggest that these species have similar adaptive ability in the habitat and occupied overlapping niches in the community.

  19. Litomosoides anguyai n. sp. (Nematoda: Onchocercidae) from Oxymycterus misionalis (Rodentia: Muridae) in the rain forest of Misiones, Argentina.

    Science.gov (United States)

    Notarnicola, Juliana; Bain, Odile; Navone, Graciela

    2002-06-01

    A new species of Litomosoides is described from sigmodontine murids occurring in the rain forests of Misiones, Argentina. Litomosoides anguyai n. sp., a parasite of the abdominal cavity of Oxymycterus misionalis, belongs to the sigmodontis group and is closely related to L. legerae and L. oxymycteri. The new species is differentiated by the salient amphids, an asymmetrical annular thickening of the buccal capsule, by the arrangement of the head and tail papillae, and the shape and size of the microfilaria.

  20. Relationships among net primary productivity, nutrients and climate in tropical rain forest: A pan-tropical analysis

    Science.gov (United States)

    Cleveland, Cory C.; Townsend, Alan R.; Taylor, Philip; Alvarez-Clare, Silvia; Bustamante, Mercedes M.C.; Chuyong, George; Dobrowski, Solomon Z.; Grierson, Pauline; Harms, Kyle E.; Houlton, Benjamin Z.; Marklein, Alison; Parton, William; Porder, Stephen; Reed, Sasha C.; Sierra, Carlos A.; Silver, Whendee L.; Tanner, Edmund V.J.; Wieder, William R.

    2011-01-01

    Tropical rain forests play a dominant role in global biosphere-atmosphere CO2 exchange. Although climate and nutrient availability regulate net primary production (NPP) and decomposition in all terrestrial ecosystems, the nature and extent of such controls in tropical forests remain poorly resolved. We conducted a meta-analysis of carbon-nutrient-climate relationships in 113 sites across the tropical forest biome. Our analyses showed that mean annual temperature was the strongest predictor of aboveground NPP (ANPP) across all tropical forests, but this relationship was driven by distinct temperature differences between upland and lowland forests. Within lowland forests (relationships were weak. However, foliar P, foliar nitrogen (N), litter decomposition rate (k), soil N and soil respiration were all directly related with total surface (0–10 cm) soil P concentrations. Our analysis provides some evidence that P availability regulates NPP and other ecosystem processes in lowland tropical forests, but more importantly, underscores the need for a series of large-scale nutrient manipulations – especially in lowland forests – to elucidate the most important nutrient interactions and controls.

  1. Distribution and Numbers of Pygmies in Central African Forests.

    Science.gov (United States)

    Olivero, Jesús; Fa, John E; Farfán, Miguel A; Lewis, Jerome; Hewlett, Barry; Breuer, Thomas; Carpaneto, Giuseppe M; Fernández, María; Germi, Francesco; Hattori, Shiho; Head, Josephine; Ichikawa, Mitsuo; Kitanaishi, Koichi; Knights, Jessica; Matsuura, Naoki; Migliano, Andrea; Nese, Barbara; Noss, Andrew; Ekoumou, Dieudonné Ongbwa; Paulin, Pascale; Real, Raimundo; Riddell, Mike; Stevenson, Edward G J; Toda, Mikako; Vargas, J Mario; Yasuoka, Hirokazu; Nasi, Robert

    2016-01-01

    Pygmy populations occupy a vast territory extending west-to-east along the central African belt from the Congo Basin to Lake Victoria. However, their numbers and actual distribution is not known precisely. Here, we undertake this task by using locational data and population sizes for an unprecedented number of known Pygmy camps and settlements (n = 654) in five of the nine countries where currently distributed. With these data we develop spatial distribution models based on the favourability function, which distinguish areas with favourable environmental conditions from those less suitable for Pygmy presence. Highly favourable areas were significantly explained by presence of tropical forests, and by lower human pressure variables. For documented Pygmy settlements, we use the relationship between observed population sizes and predicted favourability values to estimate the total Pygmy population throughout Central Africa. We estimate that around 920,000 Pygmies (over 60% in DRC) is possible within favourable forest areas in Central Africa. We argue that fragmentation of the existing Pygmy populations, alongside pressure from extractive industries and sometimes conflict with conservation areas, endanger their future. There is an urgent need to inform policies that can mitigate against future external threats to these indigenous peoples' culture and lifestyles.

  2. Distribution and Numbers of Pygmies in Central African Forests.

    Directory of Open Access Journals (Sweden)

    Jesús Olivero

    Full Text Available Pygmy populations occupy a vast territory extending west-to-east along the central African belt from the Congo Basin to Lake Victoria. However, their numbers and actual distribution is not known precisely. Here, we undertake this task by using locational data and population sizes for an unprecedented number of known Pygmy camps and settlements (n = 654 in five of the nine countries where currently distributed. With these data we develop spatial distribution models based on the favourability function, which distinguish areas with favourable environmental conditions from those less suitable for Pygmy presence. Highly favourable areas were significantly explained by presence of tropical forests, and by lower human pressure variables. For documented Pygmy settlements, we use the relationship between observed population sizes and predicted favourability values to estimate the total Pygmy population throughout Central Africa. We estimate that around 920,000 Pygmies (over 60% in DRC is possible within favourable forest areas in Central Africa. We argue that fragmentation of the existing Pygmy populations, alongside pressure from extractive industries and sometimes conflict with conservation areas, endanger their future. There is an urgent need to inform policies that can mitigate against future external threats to these indigenous peoples' culture and lifestyles.

  3. TREE STRUCTURAL DYNAMICS OF AN AREA OF MIXED RAIN FOREST IN CAMPO BELO DO SUL, SC, BRAZIL

    Directory of Open Access Journals (Sweden)

    Silvio Formento

    2004-07-01

    Full Text Available The dynamics of the arboreal structure of a Mixed Rain Forest was assessed in the period 1992-2003. The area belongs to the “Florestal Gateados company”, located in Campo Belo do Su county, in Santa Catarina State, Southern Brazil. The surwey was carried out in 16 sample units of 10 x 60 m (600 m², where all individuals with DAP > 10 cm Were registered, measured and identified. After the analysis, it could be concluded that: Lithraea brasiliensis was the most representative specie in the structure of the forest in both analised periods, and this was related to the high values of density, dominance, frequency, besides the distribution in all forest layers. The most important species, which increased their participation in the composition and structure were, Ocotea pulchella, Matayba elaeagnoides, Clethra scabra, Clethra uleana, Sebastiana commersoniana and Araucaria angustifolia; The species which decreased in their importância in the forest structure were, Myrsine coriacea Nectandra grandiflora Capsicodendron dinissi, Ilex theezans,Ilex dumosa and Xylosma ciliatifolium. The distribuition of the trees in the forest layers changed from increasing distribution in 1992 to uniformity in 2003, enhancing the increases in density of trees of the lower layer; the forest is in a successional process, indicated particularly by the dinamycs of the structure of the lower forest layers.

  4. Nutrient allocation among plant organs across 13 tree species in three Bornean rain forests with contrasting nutrient availabilities.

    Science.gov (United States)

    Aoyagi, Ryota; Kitayama, Kanehiro

    2016-07-01

    Allocation of nitrogen (N) and phosphorus (P) among plant organs is an important factor regulating growth rate, which is a key ecological process associated with plant life-history strategies. However, few studies have explored how N and P investment in photosynthetic (leaves) and non-photosynthetic (stems and roots) organs changes in relation to depletion of each element. We investigated nutrient concentrations of plant organs in relation to whole-plant nutrient concentration (total nutrient weight per total biomass) as an index of nutrient status of each individual using the saplings of the 13 species in three tropical rain forests with contrasting N and P availabilities (tropical evergreen forests and tropical heath forests). We found a steeper decrease in foliar N concentration than foliar P concentration with decreasing whole-plant nutrient concentration. Moreover, the steeper decrease in foliar N concentration was associated with relatively stable N concentration in stems, and vice versa for P. We suggest that the depletion of N is associated with a rapid dilution of foliar N because the cell walls in non-photosynthetic organs function as an N sink. On the other hand, these species can maintain foliar P concentration by decreasing stem P concentrations despites the depletion of P. Our results emphasize the significance of non-photosynthetic organs as an N sink for understanding the variation of foliar nutrient concentrations for the tree species in the three Bornean rain forests with different N and P availabilities.

  5. Primary succession of Hawaiian montane rain forest on a chronosequence of eight lava flows

    Energy Technology Data Exchange (ETDEWEB)

    Kitayama, K.; Mueller-Dombois, D. [Univ. of Hawaii at Manoa, Honolulu, HI, (United States) Dept. of Botany; Vitousek, P.M. [Stanford Univ., Stanford, CA (United States) Dept. of Biological Sciences

    1995-04-01

    The primary-successional sere of a Hawaiian montane rain forest was inferred from an age sequence of eight closely located `a`a flows (clinker type lava); 8, 50, 140, ca. 300, ca. 400, ca. 1400, ca. 3000 and ca.9000 yr, on a windward slope of Mauna Loa, Hawaii. All study sites (0.2 ha each) were at 1120-1250 m a.s.l. with 4000 mm mean annual rainfall. The 400-yr, 1400-yr, and 9000-yr flows had younger volcanic ash deposits, while the others were pure lava. Comparisons of tree size and foliar nutrients suggested that ash increased the availability of nitrogen, and subsequently standing biomass. An Unweighted Pair Group Cluster Analysis on the samples (flows) using quantitative vascular species composition revealed that clusters were correlated with age regardless of the substrate types (pure lava vs. ash), and an indirect ordination on the samples suggested that the sequence of sample scores along axis 1 was perfectly correlated with the age sequence. Although ash deposits increased biomass, they did not affect the sequence of the successional sere. Both pubescent and glabrous varieties of Metrosideros polymorpha (Myrtaceae) dominated upper canopy layers on all flows {>=} 50 yr and {<=} 1400 yr, but the pubescent variety was replaced by the glabrous on the flows {>=} 3000 yr. Lower layers were dominated initially by a mated fern, Dicranopteris linearis, up to 300 yr, and subsequently by tree ferns, Cibotium spp., to 9000 yr. The cover of Cibotium declined sightly after 3000 yr, while other native herb and shrub species increased. 43 refs, 7 figs, 4 tabs

  6. Soil respiration in tropical seasonal rain forest in Xishuangbanna, SW China

    Institute of Scientific and Technical Information of China (English)

    SHA; Liqing; ZHENG; Zheng; TANG; Jianwei; WANG; Yinghong

    2005-01-01

    With the static opaque chamber and gas chromatography technique, from January 2003 to January 2004 soil respiration was investigated in a tropical seasonal rain forest in Xishuangbanna, SW China. In this study three treatments were applied, each with three replicates: A (bare soil), B (soil+litter), and C (soil+litter+seedling). The results showed that soil respiration varied seasonally, low from December 2003 to February 2004, and high from June to July 2004. The annual average values of CO2 efflux from soil respiration differed among the treatments at 1% level, with the rank of C (14642 mgCO2· m-2. h-1)>B (12807 mgCO2· m-2. h-1)>A (9532 mgCO2· m-2. h-1). Diurnal variation in soil respiration was not apparent due to little diurnal temperate change in Xishuangbanna. There was a parabola relationship between soil respiration and soil moisture at 1% level. Soil respiration rates were higher when soil moisture ranged from 35% to 45%. There was an exponential relationship between soil respiration and soil temperature (at a depth of 5cm in mineral soil) at 1% level. The calculated Q1o values in this study,ranging from 2.03 to 2.36, were very near to those of tropical soil reported. The CO2 efflux in 2003was 5.34 kgCO2· m-2. a-1 from soil plus litter plus seedling, of them 3.48 kgCO2· m-2. a-1 from soil (accounting for 62.5%), 1.19 kgCO2· m-2. a-1 from litter (22.3%) and 0.67 kgCO2·m-2. a-1 from seedling (12.5%).

  7. Spatial distribution and interspecific associations of tree species in a tropical seasonal rain forest of China.

    Directory of Open Access Journals (Sweden)

    Guoyu Lan

    Full Text Available Studying the spatial pattern and interspecific associations of plant species may provide valuable insights into processes and mechanisms that maintain species coexistence. Point pattern analysis was used to analyze the spatial distribution patterns of twenty dominant tree species, their interspecific spatial associations and changes across life stages in a 20-ha permanent plot of seasonal tropical rainforest in Xishuangbanna, China, to test mechanisms maintaining species coexistence. Torus-translation tests were used to quantify positive or negative associations of the species to topographic habitats. The results showed: (1 fourteen of the twenty tree species were negatively (or positively associated with one or two of the topographic variables, which evidences that the niche contributes to the spatial pattern of these species. (2 Most saplings of the study species showed a significantly clumped distribution at small scales (0-10 m which was lost at larger scales (10-30 m. (3 The degree of spatial clumping deceases from saplings, to poles, to adults indicates that density-dependent mortality of the offspring is ubiquitous in species. (4 It is notable that a high number of positive small-scale interactions were found among the twenty species. For saplings, 42.6% of all combinations of species pairs showed positive associations at neighborhood scales up to five meters, but only 38.4% were negative. For poles and adults, positive associations at these distances still made up 45.5% and 29.5%, respectively. In conclusion, there is considerable evidence for the presence of positive interactions among the tree species, which suggests that species herd protection may occur in our plot. In addition, niche assembly and limited dispersal (likely contribute to the spatial patterns of tree species in the tropical seasonal rain forest in Xishuangbanna, China.

  8. Influence of salinity on bacterioplankton communities from the Brazilian rain forest to the coastal Atlantic Ocean.

    Directory of Open Access Journals (Sweden)

    Cynthia B Silveira

    Full Text Available BACKGROUND: Planktonic bacteria are recognized as important drivers of biogeochemical processes in all aquatic ecosystems, however, the taxa that make up these communities are poorly known. The aim of this study was to investigate bacterial communities in aquatic ecosystems at Ilha Grande, Rio de Janeiro, Brazil, a preserved insular environment of the Atlantic rain forest and how they correlate with a salinity gradient going from terrestrial aquatic habitats to the coastal Atlantic Ocean. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed chemical and microbiological parameters of water samples and constructed 16S rRNA gene libraries of free living bacteria obtained at three marine (two coastal and one offshore and three freshwater (water spring, river, and mangrove environments. A total of 836 sequences were analyzed by MOTHUR, yielding 269 freshwater and 219 marine operational taxonomic units (OTUs grouped at 97% stringency. Richness and diversity indexes indicated that freshwater environments were the most diverse, especially the water spring. The main bacterial group in freshwater environments was Betaproteobacteria (43.5%, whereas Cyanobacteria (30.5%, Alphaproteobacteria (25.5%, and Gammaproteobacteria (26.3% dominated the marine ones. Venn diagram showed no overlap between marine and freshwater OTUs at 97% stringency. LIBSHUFF statistics and PCA analysis revealed marked differences between the freshwater and marine libraries suggesting the importance of salinity as a driver of community composition in this habitat. The phylogenetic analysis of marine and freshwater libraries showed that the differences in community composition are consistent. CONCLUSIONS/SIGNIFICANCE: Our data supports the notion that a divergent evolutionary scenario is driving community composition in the studied habitats. This work also improves the comprehension of microbial community dynamics in tropical waters and how they are structured in relation to physicochemical

  9. Experimental drought in a tropical rain forest increases soil carbon dioxide losses to the atmosphere

    Science.gov (United States)

    Cleveland, Cory C.; Wieder, William R.; Reed, Sasha C.; Townsend, Alan R.

    2010-01-01

    Climate models predict precipitation changes for much of the humid tropics, yet few studies have investigated the potential consequences of drought on soil carbon (C) cycling in this important biome. In wet tropical forests, drought could stimulate soil respiration via overall reductions in soil anoxia, but previous research suggests that litter decomposition is positively correlated with high rainfall fluxes that move large quantities of dissolved organic matter (DOM) from the litter layer to the soil surface. Thus, reduced rainfall could also limit C delivery to the soil surface, reducing respiration rates. We conducted a throughfall manipulation experiment to investigate how 25% and 50% reductions in rainfall altered both C movement into soils and the effects of those DOM fluxes on soil respiration rates. In response to the experimental drought, soil respiration rates increased in both the -25% and -50% treatments. Throughfall fluxes were reduced by 26% and 55% in the -25% and -50% treatments, respectively. However, total DOM fluxes leached from the litter did not vary between treatments, because the concentrations of leached DOM reaching the soil surface increased in response to the simulated drought. Annual DOM concentrations averaged 7.7 ± 0.8, 11.2 ± 0.9, and 15.8 ± 1.2 mg C/L in the control, -25%, and -50% plots, respectively, and DOM concentrations were positively correlated with soil respiration rates. A laboratory incubation experiment confirmed the potential importance of DOM concentration on soil respiration rates, suggesting that this mechanism could contribute to the increase in CO2 fluxes observed in the reduced rainfall plots. Across all plots, the data suggested that soil CO2 fluxes were partially regulated by the magnitude and concentration of soluble C delivered to the soil, but also by soil moisture and soil oxygen availability. Together, our data suggest that declines in precipitation in tropical rain forests could drive higher CO2 fluxes

  10. A New Function for Modelling Diameter Frequency Distribution in the Tropical Rain Forest of Xishuangbanna, Southwest of China

    Institute of Scientific and Technical Information of China (English)

    Lu Yuanchang; Lei Xiangdong; Jiang Lei

    2003-01-01

    Permanent plots in the montane tropical rain forests in Xishuangbanna, southwest China, were established, and different empirical models, based on observation data of these plots in 1992, were built to model diameter frequency distributions. The focus of this study is on predicting accuracy of stem number in the larger diameter classes, which is much more important than that of the smaller trees, from the view of forest management, and must be adequately considered in the modelling and estimate. There exist 3 traditional ways of modelling the diameter frequency distribution: the negative exponential function model, limiting line function model, and Weibull distribution model. In this study, a new model, named as the logarithmic J-shape function, together with the others, was experimented and was found as a more suitable model for modelling works in the tropical forests.

  11. Tree diversity, composition, forest structure and aboveground biomass dynamics after single and repeated fire in a Bornean rain forest

    NARCIS (Netherlands)

    Slik, J.W.F.; Bernard, C.S.; Beek, van M.; Breman, F.C.; Eichhorn, K.A.O.

    2008-01-01

    Forest fires remain a devastating phenomenon in the tropics that not only affect forest structure and biodiversity, but also contribute significantly to atmospheric CO2. Fire used to be extremely rare in tropical forests, leaving ample time for forests to regenerate to pre-fire conditions. In recent

  12. Above-ground biomass and structure of 260 African tropical forests

    Science.gov (United States)

    Lewis, Simon L.; Sonké, Bonaventure; Sunderland, Terry; Begne, Serge K.; Lopez-Gonzalez, Gabriela; van der Heijden, Geertje M. F.; Phillips, Oliver L.; Affum-Baffoe, Kofi; Baker, Timothy R.; Banin, Lindsay; Bastin, Jean-François; Beeckman, Hans; Boeckx, Pascal; Bogaert, Jan; De Cannière, Charles; Chezeaux, Eric; Clark, Connie J.; Collins, Murray; Djagbletey, Gloria; Djuikouo, Marie Noël K.; Droissart, Vincent; Doucet, Jean-Louis; Ewango, Cornielle E. N.; Fauset, Sophie; Feldpausch, Ted R.; Foli, Ernest G.; Gillet, Jean-François; Hamilton, Alan C.; Harris, David J.; Hart, Terese B.; de Haulleville, Thales; Hladik, Annette; Hufkens, Koen; Huygens, Dries; Jeanmart, Philippe; Jeffery, Kathryn J.; Kearsley, Elizabeth; Leal, Miguel E.; Lloyd, Jon; Lovett, Jon C.; Makana, Jean-Remy; Malhi, Yadvinder; Marshall, Andrew R.; Ojo, Lucas; Peh, Kelvin S.-H.; Pickavance, Georgia; Poulsen, John R.; Reitsma, Jan M.; Sheil, Douglas; Simo, Murielle; Steppe, Kathy; Taedoumg, Hermann E.; Talbot, Joey; Taplin, James R. D.; Taylor, David; Thomas, Sean C.; Toirambe, Benjamin; Verbeeck, Hans; Vleminckx, Jason; White, Lee J. T.; Willcock, Simon; Woell, Hannsjorg; Zemagho, Lise

    2013-01-01

    We report above-ground biomass (AGB), basal area, stem density and wood mass density estimates from 260 sample plots (mean size: 1.2 ha) in intact closed-canopy tropical forests across 12 African countries. Mean AGB is 395.7 Mg dry mass ha−1 (95% CI: 14.3), substantially higher than Amazonian values, with the Congo Basin and contiguous forest region attaining AGB values (429 Mg ha−1) similar to those of Bornean forests, and significantly greater than East or West African forests. AGB therefore appears generally higher in palaeo- compared with neotropical forests. However, mean stem density is low (426 ± 11 stems ha−1 greater than or equal to 100 mm diameter) compared with both Amazonian and Bornean forests (cf. approx. 600) and is the signature structural feature of African tropical forests. While spatial autocorrelation complicates analyses, AGB shows a positive relationship with rainfall in the driest nine months of the year, and an opposite association with the wettest three months of the year; a negative relationship with temperature; positive relationship with clay-rich soils; and negative relationships with C : N ratio (suggesting a positive soil phosphorus–AGB relationship), and soil fertility computed as the sum of base cations. The results indicate that AGB is mediated by both climate and soils, and suggest that the AGB of African closed-canopy tropical forests may be particularly sensitive to future precipitation and temperature changes. PMID:23878327

  13. Comparison of seed rain and seed limitation between community understory and gaps in a subtropical evergreen forest

    Science.gov (United States)

    Du, Yanjun; Mi, Xiangcheng; Ma, Keping

    2012-10-01

    Treefall gaps have been identified as important sites for plant recruitment. In this study, we compared seed rain between forest gaps and forest interior using 150 seed traps in the understory and 19 traps in gaps in a 24 ha permanent plot of subtropical evergreen broad-leaved forest in East China. We asked how total seed abundance and seed species richness, the relative representation of different dispersal modes, and seed limitation and its components differed between canopy gaps and the understory. Results showed that most of the species found in both the understory and in gaps were animal-dispersal, but most of the seed rain was comprised of wind-dispersed species in both habitats. No significant differences in either density or diversity of seeds between gaps and non-gap sites were found. Contrary to expectations, wind-dispersed seeds did not occur significantly more in treefall gaps than in the forest understory. There were also no significant differences in seed limitation and its components (source limitation, dispersal limitation) between the understory and gaps. Seed limitation was strong for all but a few of the best-dispersed species in both gap and understory seed traps. Source and dispersal limitation showed large inter-specific variation in both the understory and in gaps. Overall, our results indicate that: (i) gaps may play a neutral role in maintaining seed diversity in this subtropical forest; (ii) under strong seed limitation both in gaps and in the understory, population and community dynamics slows and ecological drift in species composition may become a more important determinant of community structure.

  14. Retrieval of Vertical LAI Profiles Over Tropical Rain Forests using Waveform Lidar at La Selva, Costa Rica

    Science.gov (United States)

    Tang, Hao; Dubayah, Ralph; Swatantra, Anu; Hofton, Michelle; Sheldon, Sage; Clark, David B.; Blair, Bryan

    2012-01-01

    This study explores the potential of waveform lidar in mapping the vertical and spatial distributions of leaf area index (LAI) over the tropical rain forest of La Selva Biological Station in Costa Rica. Vertical profiles of LAI were derived at 0.3 m height intervals from the Laser Vegetation Imaging Sensor (LVIS) data using the Geometric Optical and Radiative Transfer (GORT) model. Cumulative LAI profiles obtained from LVIS were validated with data from 55 ground to canopy vertical transects using a modular field tower to destructively sample all vegetation. Our results showed moderate agreement between lidar and field derived LAI (r2=0.42, RMSE=1.91, bias=-0.32), which further improved when differences between lidar and tower footprint scales (r2=0.50, RMSE=1.79, bias=0.27) and distance of field tower from lidar footprint center (r2=0.63, RMSE=1.36, bias=0.0) were accounted for. Next, we mapped the spatial distribution of total LAI across the landscape and analyzed LAI variations over different land cover types. Mean values of total LAI were 1.74, 5.20, 5.41 and 5.62 over open pasture, secondary forests, regeneration forests after selective-logging and old-growth forests respectively. Lastly, we evaluated the sensitivities of our LAI retrieval model to variations in canopy/ground reflectance ratio and to waveform noise such as induced by topographic slopes. We found for both, that the effects were not significant for moderate LAI values (about 4). However model derivations of LAI might be inaccurate in areas of high-slope and high LAI (about 8) if ground return energies are low. This research suggests that large footprint waveform lidar can provide accurate vertical LAI profile estimates that do not saturate even at the high LAI levels in tropical rain forests and may be a useful tool for understanding the light transmittance within these canopies.

  15. The politics of environment and acid rain in the Federal Republic of Germany: forests versus fossil fuels

    Energy Technology Data Exchange (ETDEWEB)

    Boehmer-Christiansen, S.

    1989-09-01

    In June 1982 the Federal Government of the FRG reversed its international position on 'acid rain' and, by joining Sweden, set in motion pressures for cleaning up industrial emissions within the EEC, especially of sulphur dioxide from fossil-fuel burning power stations. This paper deals with the reasons behind this conversion and as such is a case study in environmental decision-making. This report analyses the pressures inside the Federal Republic which forced air pollution to the top of the environmental agenda in the early 1980s and describes the processes by which air pollution controls in general and the GFAVo (Ordinance on Large Firing Installations or Large Combustion Plants, Grossfeuerungsanlagenverordnung) in particular were adopted. This requires reference to both the societal context, the West German energy sector and official policies for both energy and pollution control. The turbulence of German domestic politics between 1981 and 1983 is described as an essential ingredient of policy formation. The strong regional dimensional of German policy and politics, always important, is emphasised and relates to the unequal geographical distribution of both forests and nuclear capacity. Waldsterben (or forest die-back), the still not fully understood illness of forests in Central Europe observed since the late 1970s, was very quickly ascribed to acid rain and in particular to emissions of sulphur dioxide from power stations. Both the Schmidt and Kohl administrations found in acid rain abatement policy a solution to the perceived conflict between energy and environment. This in turn allowed government to ignore, avoid or postpone confronting even more controversial and fundamentally destabilising German 'eco-issues': the future of nuclear power, the presence of foreign nuclear and chemical weapons and, above all, the nature and direction of economic growth.

  16. Towards ground-truthing of spaceborne estimates of above-ground biomass and leaf area index in tropical rain forests

    Science.gov (United States)

    Köhler, P.; Huth, A.

    2010-05-01

    The canopy height of forests is a key variable which can be obtained using air- or spaceborne remote sensing techniques such as radar interferometry or lidar. If new allometric relationships between canopy height and the biomass stored in the vegetation can be established this would offer the possibility for a global monitoring of the above-ground carbon content on land. In the absence of adequate field data we use simulation results of a tropical rain forest growth model to propose what degree of information might be generated from canopy height and thus to enable ground-truthing of potential future satellite observations. We here analyse the correlation between canopy height in a tropical rain forest with other structural characteristics, such as above-ground biomass (AGB) (and thus carbon content of vegetation) and leaf area index (LAI). The process-based forest growth model FORMIND2.0 was applied to simulate (a) undisturbed forest growth and (b) a wide range of possible disturbance regimes typically for local tree logging conditions for a tropical rain forest site on Borneo (Sabah, Malaysia) in South-East Asia. It is found that for undisturbed forest and a variety of disturbed forests situations AGB can be expressed as a power-law function of canopy height h (AGB=a·hb) with an r2~60% for a spatial resolution of 20 m×20 m (0.04 ha, also called plot size). The regression is becoming significant better for the hectare wide analysis of the disturbed forest sites (r2=91%). There seems to exist no functional dependency between LAI and canopy height, but there is also a linear correlation (r2~60%) between AGB and the area fraction in which the canopy is highly disturbed. A reasonable agreement of our results with observations is obtained from a comparison of the simulations with permanent sampling plot data from the same region and with the large-scale forest inventory in Lambir. We conclude that the spaceborne remote sensing techniques have the potential to

  17. Towards ground-truthing of spaceborne estimates of above-ground biomass and leaf area index in tropical rain forests

    Directory of Open Access Journals (Sweden)

    P. Köhler

    2010-05-01

    Full Text Available The canopy height of forests is a key variable which can be obtained using air- or spaceborne remote sensing techniques such as radar interferometry or lidar. If new allometric relationships between canopy height and the biomass stored in the vegetation can be established this would offer the possibility for a global monitoring of the above-ground carbon content on land. In the absence of adequate field data we use simulation results of a tropical rain forest growth model to propose what degree of information might be generated from canopy height and thus to enable ground-truthing of potential future satellite observations. We here analyse the correlation between canopy height in a tropical rain forest with other structural characteristics, such as above-ground biomass (AGB (and thus carbon content of vegetation and leaf area index (LAI. The process-based forest growth model FORMIND2.0 was applied to simulate (a undisturbed forest growth and (b a wide range of possible disturbance regimes typically for local tree logging conditions for a tropical rain forest site on Borneo (Sabah, Malaysia in South-East Asia. It is found that for undisturbed forest and a variety of disturbed forests situations AGB can be expressed as a power-law function of canopy height h (AGB=a·hb with an r2~60% for a spatial resolution of 20 m×20 m (0.04 ha, also called plot size. The regression is becoming significant better for the hectare wide analysis of the disturbed forest sites (r2=91%. There seems to exist no functional dependency between LAI and canopy height, but there is also a linear correlation (r2~60% between AGB and the area fraction in which the canopy is highly disturbed. A reasonable agreement of our results with observations is obtained from a comparison of the simulations with permanent sampling plot data from the same region and with the large-scale forest inventory in

  18. Effect of simulated acid rain on the litter decomposition of Quercus acutissima and Pinus massoniana in forest soil microcosms and the relationship with soil enzyme activities.

    Science.gov (United States)

    Wang, Congyan; Guo, Peng; Han, Guomin; Feng, Xiaoguang; Zhang, Peng; Tian, Xingjun

    2010-06-01

    With the continuing increase in human activities, ecologists are increasingly interested in understanding the effects of acid rain on litter decomposition. Two dominant litters were chosen from Zijin Mountain in China: Quercus acutissima from a broad-leaved forest and Pinus massoniana from a coniferous forest. The litters were incubated in microcosms and treated with simulated acid rain (gradient pH levels). During a six-month incubation, changes in chemical composition (i.e., lignin, total carbohydrate, and nitrogen), litter mass losses, soil pH values, and activities of degradative enzymes were determined. Results showed that litter mass losses were depressed after exposure to acid rain and the effects of acid rain on the litter decomposition rates of needles were higher than on those of leaves. Results also revealed that simulated acid rain restrained the activities of cellulase, invertase, nitrate reductase, acid phosphatase, alkaline phosphatase, polyphenol oxidase, and urease, while it enhanced the activities of catalase in most cases during the six-month decomposition process. Catalase and polyphenol oxidase were primarily responsible for litter decomposition in the broad-leaved forest, while invertase, nitrate reductase, and urease were primarily responsible for litter decomposition in the coniferous forest. The results suggest acid rain-restrained litter decomposition may be due to the depressed enzymatic activities. According to the results of this study, soil carbon in subtropical forests would accumulate as a long-term consequence of continued acid rain. This may presumably alter the balance of ecosystem carbon flux, nutrient cycling, and humus formation, which may, in turn, have multiple effects on forest ecosystems.

  19. Tree diversity, composition, forest structure and aboveground biomass dynamics after single and repeated fire in a Bornean rain forest.

    Science.gov (United States)

    Slik, J W Ferry; Bernard, Caroline S; Van Beek, Marloes; Breman, Floris C; Eichhorn, Karl A O

    2008-12-01

    Forest fires remain a devastating phenomenon in the tropics that not only affect forest structure and biodiversity, but also contribute significantly to atmospheric CO2. Fire used to be extremely rare in tropical forests, leaving ample time for forests to regenerate to pre-fire conditions. In recent decades, however, tropical forest fires occur more frequently and at larger spatial scales than they used to. We studied forest structure, tree species diversity, tree species composition, and aboveground biomass during the first 7 years since fire in unburned, once burned and twice burned forest of eastern Borneo to determine the rate of recovery of these forests. We paid special attention to changes in the tree species composition during burned forest regeneration because we expect the long-term recovery of aboveground biomass and ecosystem functions in burned forests to largely depend on the successful regeneration of the pre-fire, heavy-wood, species composition. We found that forest structure (canopy openness, leaf area index, herb cover, and stem density) is strongly affected by fire but shows quick recovery. However, species composition shows no or limited recovery and aboveground biomass, which is greatly reduced by fire, continues to be low or decline up to 7 years after fire. Consequently, large amounts of the C released to the atmosphere by fire will not be recaptured by the burned forest ecosystem in the near future. We also observed that repeated fire, with an inter-fire interval of 15 years, does not necessarily lead to a huge deterioration in the regeneration potential of tropical forest. We conclude that burned forests are valuable and should be conserved and that long-term monitoring programs in secondary forests are necessary to determine their recovery rates, especially in relation to aboveground biomass accumulation.

  20. Annual variation of carbon flux and impact factors in the tropical seasonal rain forest of Xishuangbanna, SW China

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    <正>Two years of eddy covariance measurements of above- and below-canopy carbon fluxes and static opaque chamber and gas chromatography technique measurements of soil respiration for three treatments (bare soil, soil+litterfall, soil+litterfall+seedling) were carried out in a tropical seasonal rain forest. In addition, data of photosynthesis of dominant tree species and seedlings, leaf area index, litter production and decomposing speed, soil moisture, soil temperature and photosynthetic photon flux density within the forest were all measured concurrently. Data from January 2003 to December 2004 are used to present annual variability of carbon flux and relationships between carbon flux and impact factors. The results show that carbon flux of this forest presented unusual tendency of annual variation; above-canopy carbon fluxes were negative in the dry season (November-April) and mainly positive in the rainy season, but overall the forest is a carbon sink. Carbon flux has obviously diurnal variation in this tropical seasonal rain forest. Above-canopy carbon fluxes were negative in the daytime and absolute values were larger in the dry season than that in the rainy season, causing the forest to act as a carbon sink; at night, carbon fluxes were mainly positive, causing the forest to act as a carbon source. Dominant tree species have greater photosynthesis capability than that of seedlings, which have a great effect on above-canopy carbon flux. There was a significant correlation between above-canopy carbon flux and rate of photosynthesis of tree species. There was also a significant correlation between above-canopy carbon flux and rate of photosynthesis of seedlings; however, the below-canopy carbon flux was only significantly correlated with rate of photosynthesis of seedlings during the hot-dry season. Soil respiration of the three treatments displayed a markedly seasonal dynamic; in addition, above-canopy carbon fluxes correlated well with soil respiration

  1. Acid rain mitigation experiment shifts a forested watershed from a net sink to a net source of nitrogen.

    Science.gov (United States)

    Rosi-Marshall, Emma J; Bernhardt, Emily S; Buso, Donald C; Driscoll, Charles T; Likens, Gene E

    2016-07-01

    Decades of acid rain have acidified forest soils and freshwaters throughout montane forests of the northeastern United States; the resulting loss of soil base cations is hypothesized to be responsible for limiting rates of forest growth throughout the region. In 1999, an experiment was conducted that reversed the long-term trend of soil base cation depletion and tested the hypothesis that calcium limits forest growth in acidified soils. Researchers added 1,189 kg Ca(2+) ha(-1) as the pelletized mineral wollastonite (CaSiO3) to a 12-ha forested watershed within the Hubbard Brook Experimental Forest in the White Mountains of New Hampshire. Significant increases in the pH and acid-neutralizing capacity of soils and streamwater resulted, and the predicted increase in forest growth occurred. An unanticipated consequence of this acidification mitigation experiment began to emerge a decade later, with marked increases in dissolved inorganic nitrogen (DIN) exports in streamwater from the treated watershed. By 2013, 30-times greater DIN was exported from this base-treated watershed than from adjacent reference watersheds, and DIN exports resulting from this experiment match or exceed earlier reports of inorganic N losses after severe ice-storm damage within the study watershed. The discovery that CaSiO3 enrichment can convert a watershed from a sink to a source of N suggests that numerous potential mechanisms drive watershed N dynamics and provides new insights into the influence of acid deposition mitigation strategies for both carbon cycling and watershed N export.

  2. Spatial and Temporal Patterns of Throughfall Amounts and Solutes in a Tropical Montane Forest - Comparisons with Findings From Lowland Rain Forests

    Science.gov (United States)

    Zimmermann, A.

    2007-05-01

    The diverse tree species composition, irregular shaped tree crowns and a multi-layered forest structure affect the redistribution of rainfall in lower montane rain forests. In addition, abundant epiphyte biomass and associated canopy humus influence spatial patterns of throughfall. The spatial variability of throughfall amounts controls spatial patterns of solute concentrations and deposition. Moreover, the living and dead biomass interacts with the rainwater during the passage through the canopy and creates a chemical variability of its own. Since spatial and temporal patterns are intimately linked, the analysis of temporal solute concentration dynamics is an important step to understand the emerging spatial patterns. I hypothesized that: (1) the spatial variability of volumes and chemical composition of throughfall is particularly high compared with other forests because of the high biodiversity and epiphytism, (2) the temporal stability of the spatial pattern is high because of stable structures in the canopy (e.g. large epiphytes) that show only minor changes during the short term observation period, and (3) the element concentrations decrease with increasing rainfall because of exhausting element pools in the canopy. The study area at 1950 m above sea level is located in the south Ecuadorian Andes far away from anthropogenic emission sources and marine influences. Rain and throughfall were collected from August to October 2005 on an event and within-event basis for five precipitation periods and analyzed for pH, K, Na, Ca, Mg, NH4+, Cl-, NO3-, PO43-, TN, TP and TOC. Throughfall amounts and most of the solutes showed a high spatial variability, thereby the variability of H+, K, Ca, Mg, Cl- and NO3- exceeded those from a Brazilian tropical rain forest. The temporal persistence of the spatial patterns was high for throughfall amounts and varied depending on the solute. Highly persistent time stability patterns were detected for K, Mg and TOC concentrations. Time

  3. Morphological Characterization of African Bush Mango trees (Irvingia species) in the Dahomey Gap (West Africa)

    NARCIS (Netherlands)

    Vihotogbe, R.; Berg, van den R.G.; Sosef, M.S.M.

    2013-01-01

    The variation of the morphological characters of bitter and sweet African bush mango trees (Irvingia species) was investigated in the Dahomey Gap which is the West African savannah woodland area separating the Upper and the Lower Guinean rain forest blocks. African bush mangoes have been rated as th

  4. Community Dynamics of Seed Rain in Mixed Evergreen Broad-leaved and Deciduous Forests in a Subtropical Mountain of Central China

    Institute of Scientific and Technical Information of China (English)

    Ze-Hao Shen; Yuan-Yuan Tang; Nan Lü; Jun Zhao; Dao-Xing Li; Gong-Fang Wang

    2007-01-01

    Seed dispersal is a key process within community dynamics. The spatial and temporal variations of seed dispersal and the interspecific differences are crucial for understanding species coexistence and community dynamics. This might also hold for the mixed evergreen broadleaved and deciduous forests in the mountains of subtropical China, but until now little existing knowledge is available for this question. In 2001, we chose to monitor the seed rain process of our mixed evergreen broad-leaved and deciduous forest communities in Mount Dalaoling National Forest Park, Yichang, Hubei Province, China.The preliminary analyses show obvious variations in seed rain density, species compositions and timing of seed rain among four communities. The average seed rain densities of the four communities are 2.43 ± 5.15, 54.13 ±182.75, 10.05 ±19.30and 24.91 ± 58.86 inds./m2, respectively; about one tenth the values in other studies in subtropical forests of China. In each community, the seed production is dominated by a limited number of species, and the contributions from the others are generally minor. Fecundity of evergreen broadleaved tree species is weaker than deciduous species. The seed rain of four communities begins earlier than September, and stops before December, peaking from early September to late October.The beginning date, ending date and peak times of seed rain are extensively varied among the species, indicating different types of dispersal strategies. According to the existing data, the timing of seed rain is not determined by the climate conditions in the same period, while the density of seed rain may be affected by the disturbances of weather variations at a finer temporal resolution.

  5. Hyperparasitoid wasps (Hymenoptera, Trigonalidae reared from dry forest and rain forest caterpillars of Area de Conservación Guanacaste, Costa Rica

    Directory of Open Access Journals (Sweden)

    David Smith

    2012-10-01

    Full Text Available Five species of Trigonalidae, hyperparasitoids of Ichneumonidae (Hymenoptera and Tachinidae (Diptera that parasitize caterpillars (Lepidoptera, have been reared during the ongoing caterpillar inventory of Area de Conservación Guanacaste (ACG, Guanacaste Province, northwestern Costa Rica: Lycogaster apicipennis (Cameron, Taeniogonalos woodorum Smith, sp. n., Taeniogonalos fasciatipennis (Cameron, Trigonalys championi Cameron, and Trigonalys maculifrons Sharp. Morphological and DNA barcoding data support species separation of these generalist hyperparasitoids. Taeniogonalos gundlachii (Cresson is not a widespread, color-variable species as previously treated and is probably confined to eastern North America. The species previously considered as T. gundlachii in Costa Rica is regarded as Taeniogonalos fasciatipennis, a species found only in ACG dry forest. Taeniogonalos woodorum is a similar species but found only in the ACG rain forest. Habitat and host records are given for these five species of trigonalids.

  6. Horizontal stratification of the sand fly fauna (Diptera: Psychodidae) in a transitional vegetation between caatinga and tropical rain forest, state of Bahia, Brazil.

    Science.gov (United States)

    Dias-Lima, Artur Gomes; Guedes, Maria Lenise Silva; Sherlock, Italo A

    2003-09-01

    A study about the horizontal stratification of the sand fly fauna in two distinct ecosystems, caatinga area, endemic for visceral leishmaniasis, and the tropical rain forest area, endemic for cutaneous leishmaniasis, was performed in the state of Bahia, Brazil. Lutzomyia longipalpis was predominant in the caatinga, and following it came the species L. capixaba and L. oswaldoi. In the tropical rain forest other species were found, such as L. intermedia, L. migonei, L. whitmani, L. yuilli, L.fischeri, L. damascenoi, L. evandroi, L. monticola, and L. lenti. It was found that the geographical limits of the vector species of visceral and cutaneous leishmaniasis are clearly defined by the biological and phytogeographic characteristics.

  7. SPECTRAL AND TEXTURAL CHARACTERISTICS OF THE LOWLAND TROPICAL RAIN FOREST OF JAMBI, SUMATERA

    Directory of Open Access Journals (Sweden)

    UPIK ROSALINA WASRIN

    1999-01-01

    Full Text Available Analyses of Landsat TM and SPOT multispectral data were performed with a very detailed description of the vegetation cover in the field to get a relevancy and consistency of digital image classification in a semi-automatic approach. Three main vegetation types, i.e. primary forest, logged-over forest and secondary forest after clear cut were analyzed and the microclimatic parameters were also measured to describe the ecological condition of the vegetation. Spectral and textural analysis of data obtained from field measurements and spectral reflectance values of the remote sensing data are the main topic of this report as one aspect of study on the Digital Method of Detection and Monitoring on Forest Ecosystem Change Using High Resolution Satellite Data funded by the Indonesian National Research Council. This study shows that spectral reflectance values alone cannot differentiate the logged-over forest from the primary forest, but it is very sharply distinguished from the secondary forest. As for the texture analysis, it is possible to distinguish the logged-over forest from the primary forest, as shown by different values of degree of Entropy, although spatially, it is still doubtful.

  8. Palynological reconstruction of the rain forest in French Guiana during the past 3000 years; Reconstitution palynologique de la foret guyanaise au cours des 3000 dernieres annees

    Energy Technology Data Exchange (ETDEWEB)

    Ledru, M.P.; Fournier, M.; Martin, L. [ORSTOM, 93 - Bondy (France); Charles-Dominique, P.; Riera, B. [Laboratoire d`ecologie generale, URA, CNRS, 91 - Brunoy (France); Tardy, Ch. [Laboratoire de paleobotanique, URA, CNRS, Institut de botanique 34 - Montpellier (France)

    1997-03-01

    Pollen analysis has been carried out on a core drilled in a peaty palm swamp forest in the rain forest of French Guiana. This has brought new data on the variations of the forest cover during the past 3000 years. Momentary peaks of the pioneer species Cecropia frequency give evidence of two phases of relatively open vegetation: on between 2124 - 1679 and 1525 - 1375 calibrated years B.P. and another shorter one around 658-424 yrs B.P. cal. The first one appears to be due to the combined incidence of a dry climatic period and of forest fires of human origins. (authors). 13 refs.

  9. Seeds, saplings and gaps: size matters. A study in the tropical rain forest of Guyana

    NARCIS (Netherlands)

    Rose, S.A.

    2001-01-01

    Forest management for timber exploitation is dependent on the succesful regeneration of commercial timber species in gaps. This study evaluated the influence of gap size and seed mass on the processes of seedling recruitment, establishment, growth and survival in logged over and mature forest

  10. Come Rain or Shine: A Whole School Approach to Forest School

    Science.gov (United States)

    Vandewalle, Martyn

    2010-01-01

    This article begins by describing a typical Forest School session that takes place in every class every week at The Wroxham School in Potters Bar. It goes on to outline a brief history of Forest School from its inception, its aims and ethos, and how it has been adapted for the ethos and needs of the children at Wroxham. The article also looks at…

  11. SPATIAL CONTAGIOUSNESS OF CANOPY DISTURBANCE IN TROPICAL RAIN FOREST : AN INDIVIDUAL-TREE-BASED TEST

    NARCIS (Netherlands)

    Jansen, Patrick A.; Van Der Meer, Peter J.; Bongers, Frans

    2008-01-01

    Spatial contagiousness of canopy dynamics-the tendency of canopy disturbances to occur nearby existing canopy openings due to an elevated risk of tree fall around gaps-has been demonstrated in many temperate-zone forests, but only inferentially for tropical forests. Hypothesized mechanisms increasin

  12. Disturbance regimes, gap-demanding trees and seed mass related to tree height in warm temperate rain forests worldwide.

    Science.gov (United States)

    Grubb, Peter J; Bellingham, Peter J; Kohyama, Takashi S; Piper, Frida I; Valido, Alfredo

    2013-08-01

    For tropical lowland rain forests, Denslow (1987) hypothesized that in areas with large-scale disturbances tree species with a high demand for light make up a larger proportion of the flora; results of tests have been inconsistent. There has been no test for warm temperate rain forests (WTRFs), but they offer a promising testing ground because they differ widely in the extent of disturbance. WTRF is dominated by microphylls sensu Raunkiaer and has a simpler structure and range of physiognomy than tropical or subtropical rain forests. It occurs in six parts of the world: eastern Asia, New Zealand, Chile, South Africa, SE Australia and the Azores. On the Azores it has been mostly destroyed, so we studied instead the subtropical montane rain forest (STMRF) on the Canary Islands which also represents a relict of the kind of WTRF that once stretched across southern Eurasia. We sought to find whether in these six regions the proportion of tree species needing canopy gaps for establishment reflects the frequency and/or extent of canopy disturbance by wind, landslide, volcanic eruptions (lava flow and ash fall), flood or fire. We used standard floras and ecological accounts to draw up lists of core tree species commonly reaching 5 m height. We excluded species which are very rare, very localized in distribution, or confined to special habitats, e.g. coastal forests or rocky sites. We used published accounts and our own experience to classify species into three groups: (1) needing canopy gaps for establishment; (2) needing either light shade throughout or a canopy gap relatively soon (a few months or years) after establishment; and (3) variously more shade-tolerant. Group 1 species were divided according the kind of canopy opening needed: tree-fall gap, landslide, lava flow, flood or fire. Only some of the significant differences in proportion of Group 1 species were consistent with differences in the extent of disturbance; even in some of those cases other factors seem

  13. African Savanna-Forest Boundary Dynamics: A 20-Year Study.

    Directory of Open Access Journals (Sweden)

    Aida Cuni-Sanchez

    Full Text Available Recent studies show widespread encroachment of forest into savannas with important consequences for the global carbon cycle and land-atmosphere interactions. However, little research has focused on in situ measurements of the successional sequence of savanna to forest in Africa. Using long-term inventory plots we quantify changes in vegetation structure, above-ground biomass (AGB and biodiversity of trees ≥10 cm diameter over 20 years for five vegetation types: savanna; colonising forest (F1, monodominant Okoume forest (F2; young Marantaceae forest (F3; and mixed Marantaceae forest (F4 in Lopé National Park, central Gabon, plus novel 3D terrestrial laser scanning (TLS measurements to assess forest structure differences. Over 20 years no plot changed to a new stage in the putative succession, but F1 forests strongly moved towards the structure, AGB and diversity of F2 forests. Overall, savanna plots showed no detectable change in structure, AGB or diversity using this method, with zero trees ≥10 cm diameter in 1993 and 2013. F1 and F2 forests increased in AGB, mainly as a result of adding recruited stems (F1 and increased Basal Area (F2, whereas F3 and F4 forests did not change substantially in structure, AGB or diversity. Critically, the stability of the F3 stage implies that this stage may be maintained for long periods. Soil carbon was low, and did not show a successional gradient as for AGB and diversity. TLS vertical plant profiles showed distinctive differences amongst the vegetation types, indicating that this technique can improve ecological understanding. We highlight two points: (i as forest colonises, changes in biodiversity are much slower than changes in forest structure or AGB; and (ii all forest types store substantial quantities of carbon. Multi-decadal monitoring is likely to be required to assess the speed of transition between vegetation types.

  14. Soil profile, relief features and their relation to structure and distribution of Brazilian Atlantic rain forest trees

    Directory of Open Access Journals (Sweden)

    Frederico Augusto Guimarães Guilherme

    2012-02-01

    Full Text Available In tropical forests, the environmental heterogeneity can provide niche partitioning at local scales and determine the diversity and plant species distribution. Thus, this study aimed to investigate the variations of tree species structure and distribution in response to relief and soil profile features in a portion of the largest remnant of Brazilian Atlantic rain forest. All trees ³ 5 cm diameter at breast height were recorded in two 0.99 ha plots. Topographic survey and a soil characterization were accomplished in both plots. Topsoil samples (0-20 cm were taken from 88 quadrats and analyzed for chemical and particle size properties. Differences for both diversity and tree density were identified among three kinds of soils. A canonical correspondence analysis (CCA indicated that the specific abundance varied among the three kinds of soils mapped: a shallow Udept - Orthent / Aquent gradient, probably due to differences in soil drainage. Nutrient content was less likely to affect tree species composition and distribution than relief, pH, Al3+, and soil texture. Some species were randomly distributed and did not show restriction to relief and soil properties. However, preferences in niche occupation detected in this study, derived from the catenary environments found, rise up as an important explanation for the high tree species diversity in tropical forests.

  15. Towards ground-truthing of spaceborne estimates of above-ground life biomass and leaf area index in tropical rain forests

    OpenAIRE

    Köhler, P.; Huth, A.

    2010-01-01

    The canopy height h of forests is a key variable which can be obtained using air- or spaceborne remote sensing techniques such as radar interferometry or LIDAR. If new allometric relationships between canopy height and the biomass stored in the vegetation can be established this would offer the possibility for a global monitoring of the above-ground carbon content on land. In the absence of adequate field data we use simulation results of a tropical rain forest growth model...

  16. Effects of antecedent rain history on particulate phosphorus loss from a small forested watershed of Japanese cypress ( Chamaecyparis obtusa)

    Science.gov (United States)

    Ide, Jun'ichiro; Haga, Hirokazu; Chiwa, Masaaki; Otsuki, Kyoichi

    2008-05-01

    SummaryThis study aimed to clarify the effects of antecedent rain history on particulate phosphorus (PP) loss in a small mountainous watershed covered primarily with a plantation forest of Japanese cypress (Chamaecyparis obtusa). We analyzed stream discharge and PP concentration at 15-60 min intervals during 24 h in eight rain events with different discharge levels. The PP concentration versus stream discharge (PPC-Q) relationships exhibited clockwise hysteresis loops for each of the eight events monitored. Discharge could explain changes in PP concentration on the falling but not rising limb of the hydrograph. On the rising limb, a positive relationship between the rate of changes in discharge (dQ/dt) and the PP load (dL/dt) was found for each event. This indicates that a large amount of PP is strongly pulsed at times of rapidly increased discharge. These results suggest that dQ/dt is the driving force behind PP supply and the primary control on the clockwise hysteresis loop of PPC-Q relationship. There was a strong negative correlation between the antecedent precipitation index and the slope of the dL/dt versus dQ/dt relationship. This shows that a rapid increase in PP load occurs even with slight increases in discharge as antecedent moisture conditions become drier. The soil water repellency and rapid runoff response following dry conditions support that soil desiccation increases the PP supply associated with soil erosion via overland flow. Therefore, we concluded that the antecedent rain history affects the mobility of PP via soil desiccation. The findings of this study will fill gaps in our understanding of temporal variations in released fine sediment and associated PP as reported in previous studies.

  17. Dispersal limitation of Tillandsia species correlates with rain and host structure in a central Mexican tropical dry forest

    Science.gov (United States)

    2017-01-01

    Seed dispersal permits the colonization of favorable habitats and generation of new populations, facilitating escape from habitats that are in decline. There is little experimental evidence of the factors that limit epiphyte dispersion towards their hosts. In a tropical dry forest in central Mexico, we monitored the phenology of dispersion of epiphyte species of the genus Tillandsia; we tested experimentally whether precipitation could cause failures in seed dispersal and whether seed capture differs among vertical strata and between host species with high (Bursera copallifera) and low (Conzattia multiflora) epiphyte loads. With the exception of one species that presents late dispersion and low abundance, all of the species disperse prior to the onset of the rainy season. However, early rains immobilize the seeds, affecting up to 24% of the fruits in species with late dispersion. We observed that Tillandsia seeds reach both Bursera and Conzattia hosts, but found that adherence to the host is 4–5 times higher in Bursera. Furthermore, seeds liberated from Bursera travel shorter distances and up to half may remain within the same crown, while the highest seed capture takes place in the upper strata of the trees. We conclude that dispersion of Tillandsia seeds is limited by early rains and by the capture of seeds within the trees where populations concentrate. This pattern of capture also helps to explain the high concentrations of epiphytes in certain hosts, while trees with few epiphytes can be simultaneously considered deficient receivers and efficient exporters of seeds. PMID:28158320

  18. Test of newly developed conceptual hydrological model for simulation of rain-on-snow events in forested watershed

    Directory of Open Access Journals (Sweden)

    Si-min QU

    2013-01-01

    Full Text Available A conceptual hydrological model that links the Xin’anjiang hydrological model and a physically based snow energy and mass balance model, described as the XINSNOBAL model, was developed in this study for simulating rain-on-snow events that commonly occur in the Pacific Northwest of the United States. The resultant model was applied to the Lookout Creek Watershed in the H. J. Andrews Experimental Forest in the western Cascade Mountains of Oregon, and its ability to simulate streamflow was evaluated. The simulation was conducted at 24-hour and one-hour time scales for the period of 1996 to 2005. The results indicated that runoff and peak discharge could be underestimated if snowpack accumulation and snowmelt under rain-on-snow conditions were not taken into account. The average deterministic coefficient of the hourly model in streamflow simulation in the calibration stage was 0.837, which was significantly improved over the value of 0.762 when the Xin’anjiang model was used alone. Good simulation performance of the XINSNOBAL model in the WS10 catchment, using the calibrated parameter of the Lookout Creek Watershed for proxy-basin testing, demonstrates that transplanting model parameters between similar watersheds can provide a useful tool for discharge forecasting in ungauged basins.

  19. Dispersal limitation of Tillandsia species correlates with rain and host structure in a central Mexican tropical dry forest.

    Science.gov (United States)

    Victoriano-Romero, Elizabeth; Valencia-Díaz, Susana; Toledo-Hernández, Víctor Hugo; Flores-Palacios, Alejandro

    2017-01-01

    Seed dispersal permits the colonization of favorable habitats and generation of new populations, facilitating escape from habitats that are in decline. There is little experimental evidence of the factors that limit epiphyte dispersion towards their hosts. In a tropical dry forest in central Mexico, we monitored the phenology of dispersion of epiphyte species of the genus Tillandsia; we tested experimentally whether precipitation could cause failures in seed dispersal and whether seed capture differs among vertical strata and between host species with high (Bursera copallifera) and low (Conzattia multiflora) epiphyte loads. With the exception of one species that presents late dispersion and low abundance, all of the species disperse prior to the onset of the rainy season. However, early rains immobilize the seeds, affecting up to 24% of the fruits in species with late dispersion. We observed that Tillandsia seeds reach both Bursera and Conzattia hosts, but found that adherence to the host is 4-5 times higher in Bursera. Furthermore, seeds liberated from Bursera travel shorter distances and up to half may remain within the same crown, while the highest seed capture takes place in the upper strata of the trees. We conclude that dispersion of Tillandsia seeds is limited by early rains and by the capture of seeds within the trees where populations concentrate. This pattern of capture also helps to explain the high concentrations of epiphytes in certain hosts, while trees with few epiphytes can be simultaneously considered deficient receivers and efficient exporters of seeds.

  20. In tropical lowland rain forests monocots have tougher leaves than dicots, and include a new kind of tough leaf

    DEFF Research Database (Denmark)

    Dominy, N.J.; Grubb, P.J.; Jackson, R.V.

    2008-01-01

    -tolerant or gap-demanding species were considered. Conclusions: It is predicted that monocots will be found to experience lower rates of herbivory by invertebrates than dicots. The tough monocot leaves include both stiff leaves containing relatively little water at saturation (e.g. palms), and leaves which lack...... stiffness, are rich in water at saturation and roll readily during dry weather or even in bright sun around midday (e.g. gingers, heliconias and marants). Monocot leaves also show that it is possible for leaves to be notably tough throughout the expansion phase of development, something never recorded...... for dicots. The need to broaden the botanist's mental picture of a ‘tough leaf' is emphasized.   Key words: Dicots, fracture toughness, herbivory, leaves, monocots, punch strength, tropical rain forest  ...

  1. Monocot leaves are eaten less than dicot leaves in tropical lowland rain forests: correlations with toughness and leaf presentation

    DEFF Research Database (Denmark)

    Grubb, P.J.; Jackson, R.V.; Barberis, I.M.

    2008-01-01

    : At six sites on four continents, estimates were made of lamina area loss from the four most recently mature leaves of focal monocots and of the nearest dicot shoot. Measurements of leaf mass per unit area, and the concentrations of water and nitrogen were made for many of the species. In Panama...... of leaf mass per unit area, or concentrations of water or nitrogen. At only one site was the increase in loss from first to fourth mature leaf significant (also large and the same in monocots and dicots), but the losses sustained during expansion were much smaller in the monocots. In the leaf-cutter ant...... insects in tropical lowland rain forest, and that the relative importance varies widely with species. The difficulties of establishing unequivocally the roles of leaf toughness and leaf folding or rolling in a given case are discussed. Key words: anti-herbivore defences, dicots, herbivory, leaf folding...

  2. Gap Dynamics and Tree Species Diversity in a Tropical Montane Rain Forest of Hainan Island,China

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Based on investigation of 53 gaps and 25 quadrats (15m×15m each) of non-gap closed stand in an old-growth tropical montane rain forest of Hainan Island, China, canopy disturbance regimes and gap regeneration were studied. Gaps were elliptical in horizontal form, the ratio of long axis /short axis was about 1.4. Percentage of expanded gaps (EG) and canopy gaps (CG) area in the landscape were 53.5% and 25.2% respectively. EG ranged from 31.4 m2 to 488.2m2 and CG/rom 14.9m2 to 354.2m2, their average sizes ...

  3. The tropical rain forests of Suriname : exploitation and management 1600-1975

    Directory of Open Access Journals (Sweden)

    Peter Boomgaard

    1992-07-01

    Full Text Available First, an introduction of the geomorphology of Suriname and the characteristics of its forests is given. Then, the author explains how it is possible that Suriname still has a high proportion of tropical rainforest while it has been a plantation economy for centuries. He looks at the usual sources of destruction of wooded areas, government policy, role of the Forest Service, and Western enterprise.

  4. Biodiversity assessment in incomplete inventories: leaf litter ant communities in several types of Bornean rain forest.

    Directory of Open Access Journals (Sweden)

    Martin Pfeiffer

    Full Text Available Biodiversity assessment of tropical taxa is hampered by their tremendous richness, which leads to large numbers of singletons and incomplete inventories in survey studies. Species estimators can be used for assessment of alpha diversity, but calculation of beta diversity is hampered by pseudo-turnover of species in undersampled plots. To assess the impact of unseen species, we investigated different methods, including an unbiased estimator of Shannon beta diversity that was compared to biased calculations. We studied alpha and beta diversity of a diverse ground ant assemblage from the Southeast Asian island of Borneo in different types of tropical forest: diperocarp forest, alluvial forest, limestone forest and heath forests. Forests varied in plant composition, geology, flooding regimes and other environmental parameters. We tested whether forest types differed in species composition and if species turnover was a function of the distance between plots at different spatial scales. As pseudo-turnover may bias beta diversity we hypothesized a large effect of unseen species reducing beta diversity. We sampled 206 ant species (25% singletons from ten subfamilies and 55 genera. Diversity partitioning among the four forest types revealed that whereas alpha species richness and alpha Shannon diversity were significantly smaller than expected, beta-diversity for both measurements was significantly higher than expected by chance. This result was confirmed when we used the unbiased estimation of Shannon diversity: while alpha diversity was much higher, beta diversity differed only slightly from biased calculations. Beta diversity as measured with the Chao-Sørensen or Morisita-Horn Index correlated with distance between transects and between sample points, indicating a distance decay of similarity between communities. We conclude that habitat heterogeneity has a high influence on ant diversity and species turnover in tropical sites and that unseen species

  5. A monocarpic tree species in a polycarpic world: how can Tachigali vasquezii maintain itself so successfully in a tropical rain forest community?

    NARCIS (Netherlands)

    Poorter, L.; Zuidema, P.A.; Peña-Claros, M.; Boot, R.

    2005-01-01

    1. Although monocarpy is rare among long-lived plant species that grow in stable habitats, one monocarpic species, Tachigali vasquezii, is extremely abundant in the rain forests of the Bolivian Amazon. We analyse how T. vasquezii is able to maintain itself successfully by comparing its life-history

  6. Leaf function in tropical rain forest canopy trees: the effect of light on leaf morphology and physiology in different-sized trees

    NARCIS (Netherlands)

    Rijkers, T.

    2000-01-01

    In this thesis the effect of constant and fluctuating light availability on several leaf traits was studied for naturally growing trees of different sizes, i.e . from sapling to adult canopy tree, of five species in a tropical rain forest in French Guiana. Leaf acclimation responses were examined th

  7. Tracing the Sources of Atmospheric Phosphorus Deposition to a Tropical Rain Forest in Panama Using Stable Oxygen Isotopes.

    Science.gov (United States)

    Gross, A; Turner, B L; Goren, T; Berry, A; Angert, A

    2016-02-01

    Atmospheric dust deposition can be a significant source of phosphorus (P) in some tropical forests, so information on the origins and solubility of atmospheric P is needed to understand and predict patterns of forest productivity under future climate scenarios. We characterized atmospheric dust P across a seasonal cycle in a tropical lowland rain forest on Barro Colorado Nature Monument (BCNM), Republic of Panama. We traced P sources by combining remote sensing imagery with the first measurements of stable oxygen isotopes in soluble inorganic phosphate (δ(18)OP) in dust. In addition, we measured soluble inorganic and organic P concentrations in fine (1 μm) aerosol fractions and used this data to estimate the contribution of P inputs from dust deposition to the forest P budget. Aerosol dry mass was greater in the dry season (December to April, 5.6-15.7 μg m(-3)) than the wet season (May to November, 3.1-7.1 μg m(-3)). In contrast, soluble P concentrations in the aerosols were lower in the dry season (980-1880 μg P g(-1)) than the wet season (1170-3380 μg P g(-1)). The δ(18)OP of dry-season aerosols resembled that of nearby forest soils (∼19.5‰), suggesting a local origin. In the wet season, when the Trans-Atlantic Saharan dust belt moves north close to Panama, the δ(18)OP of aerosols was considerably lower (∼15.5‰), suggesting a significant contribution of long-distance dust P transport. Using satellite retrieved aerosol optical depth (AOD) and the P concentrations in aerosols we sampled in periods when Saharan dust was evident we estimate that the monthly P input from long distance dust transport during the period with highest Saharan dust deposition is 88 ± 31 g P ha(-1) month(-1), equivalent to between 10 and 29% of the P in monthly litter fall in nearby forests. These findings have important implications for our understanding of modern nutrient budgets and the productivity of tropical forests in the region under future climate scenarios.

  8. The impacts of selective logging and clear-cutting on woody plant diversity after 40years of natural recovery in a tropical montane rain forest, south China.

    Science.gov (United States)

    Ding, Yi; Zang, Runguo; Lu, Xinghui; Huang, Jihong

    2017-02-01

    Historically, clear-cutting and selective logging have been the commercial logging practices. However, the effect of these pervasive timber extraction methods on biodiversity in tropical forests is still poorly understood. In this study, we compared abiotic factors, species diversity, community composition, and structure between ca. 40-year-old clear-cut (MCC); ca. 40-year-old selectively logged (MSL); and tropical old growth montane rain forests (MOG) on Hainan Island, China. Results showed that there were a large number of trees with a diameter at breast height (DBH) <30cm in the two logged forests. Additionally, the two logged forests only had 40% of the basal area of the large trees (DBH≥30cm) found in the old growth forest. The species richness and Shannon-Wiener diversity indices generally showed no difference among the three forest types. MCC had 70% of the species richness of the large trees in the MOG, whereas MSL and MOG had similar species richness. High value timber species had similar species richness among the three forest types, but a lower abundance and basal area of large trees in MCC. The species composition was distinct between the three forests. Large trees belonging to the family Fagaceae dominated in the logged forests and played a more important role in the old growth forest. Huge trees (DBH≥70cm) were rare in MCC, but were frequently found in MSL. Most abiotic factors varied inconsistently among the three forest types and few variables related to species diversity, community structure and composition. Our study indicated that MSL had a relatively faster recovery rate than MCC in a tropical montane rain forest after 40years, but both logged forests had a high recovery potential over a long-term.

  9. Tropical rain forest structure, tree growth and dynamics along a 2700-m elevational transect in Costa Rica.

    Directory of Open Access Journals (Sweden)

    David B Clark

    Full Text Available Rapid biological changes are expected to occur on tropical elevational gradients as species migrate upslope or go extinct in the face of global warming. We established a series of 9 1-ha plots in old-growth tropical rainforest in Costa Rica along a 2700 m relief elevational gradient to carry out long-term monitoring of tropical rain forest structure, dynamics and tree growth. Within each plot we mapped, identified, and annually measured diameter for all woody individuals with stem diameters >10 cm for periods of 3-10 years. Wood species diversity peaked at 400-600 m and decreased substantially at higher elevations. Basal area and stem number varied by less than two-fold, with the exception of the 2800 m cloud forest summit, where basal area and stem number were approximately double that of lower sites. Canopy gaps extending to the forest floor accounted for <3% of microsites at all elevations. Height of highest crowns and the coefficient of variation of crown height both decreased with increasing elevation. Rates of turnover of individuals and of stand basal area decreased with elevation, but rates of diameter growth and stand basal area showed no simple relation to elevation. We discuss issues encountered in the design and implementation of this network of plots, including biased sampling, missing key meteorological and biomass data, and strategies for improving species-level research. Taking full advantage of the major research potential of tropical forest elevational transects will require sustaining and extending ground based studies, incorporation of new remotely-sensed data and data-acquisition platforms, and new funding models to support decadal research on these rapidly-changing systems.

  10. Species Effects on Stand-Level Nutrient Economy of a Costa Rican Rain Forest

    Science.gov (United States)

    Wood, T. E.; Emanuel, R. E.; Tully, K.; Lawrence, D.

    2007-12-01

    In tropical ecosystems, successional forests are rapidly replacing old growth forests as the dominant forest type. This shift in successional status combined with projected changes in climate could result in a significant change in the species composition of tropical forests. How changes in species composition could affect stand-level nutrient economy is not well understood. Using species-specific leaf litter nutrient and productivity data combined with randomly generated dominance scenarios, we investigated species effects on leaf litter nutrient inputs. We conducted this research in a 1-ha secondary forest stand (30-yr in 2003) in northeastern Costa Rica. We measured senesced leaf N and P contents of the nine dominant canopy tree species within the study plot and scaled the results to the stand level using % basal area (BA) as a proxy for relative litter contribution (Sum[total leaf litterfall x % BAsp x nutrient concentrationsp]). We created different dominance scenarios using Monte Carlo generated BA distributions of the nine species. We then selected all scenarios in which one of the nine species accounted for greater than 30% of the BA. This allowed us to create communities with each of the nine species as dominant while varying the composition of the remaining tree community. Both N and P leaf litter inputs differed significantly when the dominant species changed from the current forest community. The change in N inputs was relatively small in relation to the potential change in leaf litter P inputs. P inputs decreased by 23% when Vochysia ferruginea, a shade-intolerant late pioneer species, was dominant. When Casearia arborea, a shade-tolerant species, was the dominant species there was 6% increase in leaf litter P inputs. Our results demonstrate that changes in leaf litter N and P cycling will likely occur as land use and climate change alter forest community composition.

  11. African Savanna-Forest Boundary Dynamics: A 20-Year Study

    NARCIS (Netherlands)

    Cuni-Sanchez, Aida; White, Lee J.T.; Calders, Kim; Jeffery, Kathryn J.; Abernethy, Katharine; Burt, Andrew; Disney, Mathias; Gilpin, Martin; Gomez-Dans, Jose L.; Lewis, Simon L.

    2016-01-01

    Recent studies show widespread encroachment of forest into savannas with important consequences for the global carbon cycle and land-atmosphere interactions. However, little research has focused on in situ measurements of the successional sequence of savanna to forest in Africa. Using long-term inve

  12. Spatial variation of seed rain and seed banks in gaps of karst forest in the Maolan Nature Reserve, Guizhou Province

    Institute of Scientific and Technical Information of China (English)

    Cuiling LONG; Shixiao YU

    2008-01-01

    Based on an investigation on gaps and non-gap stands of the Maolan National Karst Forest Nature Reserve, Guizhou Province, quantitative characteristics and dynamic changes of seed rain and seed banks in gaps were analyzed. The results show that the total amount of seed rain was 117.4 ± 32.6 seeds/m2 during the period of observation. The number of immature seeds was 56.3 ± 10.3 seeds/m2, that of mature damaged seeds was 15.7 ± 4.7 seeds/m2, and the number of mature germinated seeds was 45.4 ± 8.2 seeds/m2 It is suggested that the seed number is rich for gap regeneration. Seed rain in gaps has spatial and temporal heterogeneities which deeply affect regeneration patterns of gap plants. Along a gradient from the gap center to a non-gap stand, seed density in the litter layer, the number of species, and the Shannon-Wiener diversity index were gradually reduced, but these indices increased in the soil. The seed density in the gap center was 2415 ± 639 seeds/m2, near the gap center was 2218 ± 421 seeds/m2 and at the gap border area 1815 ± 311 seeds/m2. This shows that plants in gaps have good latent regenera-tion potential. In both gaps and non-gap stands, the Jaccard similarity index of seed in litter layer was the lar-gest, second largest at 5-10 cm soil depth, and the least at the 0-5 cm soil layer the index. The Jaccard index between the soil seed bank and the present plant community was large in the litter layer, but decreased with soil depth both in gaps and non-gap stands. The results show that soil seed banks are the main source of gap regeneration in the karst forests of Maolan and contribute significantly to gap regeneration.

  13. Seeing Central African forests through their largest trees

    Science.gov (United States)

    Bastin, J.-F.; Barbier, N.; Réjou-Méchain, M.; Fayolle, A.; Gourlet-Fleury, S.; Maniatis, D.; de Haulleville, T.; Baya, F.; Beeckman, H.; Beina, D.; Couteron, P.; Chuyong, G.; Dauby, G.; Doucet, J.-L.; Droissart, V.; Dufrêne, M.; Ewango, C.; Gillet, J. F.; Gonmadje, C. H.; Hart, T.; Kavali, T.; Kenfack, D.; Libalah, M.; Malhi, Y.; Makana, J.-R.; Pélissier, R.; Ploton, P.; Serckx, A.; Sonké, B.; Stevart, T.; Thomas, D. W.; de Cannière, C.; Bogaert, J.

    2015-08-01

    Large tropical trees and a few dominant species were recently identified as the main structuring elements of tropical forests. However, such result did not translate yet into quantitative approaches which are essential to understand, predict and monitor forest functions and composition over large, often poorly accessible territories. Here we show that the above-ground biomass (AGB) of the whole forest can be predicted from a few large trees and that the relationship is proved strikingly stable in 175 1-ha plots investigated across 8 sites spanning Central Africa. We designed a generic model predicting AGB with an error of 14% when based on only 5% of the stems, which points to universality in forest structural properties. For the first time in Africa, we identified some dominant species that disproportionally contribute to forest AGB with 1.5% of recorded species accounting for over 50% of the stock of AGB. Consequently, focusing on large trees and dominant species provides precise information on the whole forest stand. This offers new perspectives for understanding the functioning of tropical forests and opens new doors for the development of innovative monitoring strategies.

  14. Distinguishing forest and savanna African elephants using short nuclear DNA sequences.

    Science.gov (United States)

    Ishida, Yasuko; Demeke, Yirmed; van Coeverden de Groot, Peter J; Georgiadis, Nicholas J; Leggett, Keith E A; Fox, Virginia E; Roca, Alfred L

    2011-01-01

    A more complete description of African elephant phylogeography would require a method that distinguishes forest and savanna elephants using DNA from low-quality samples. Although mitochondrial DNA is often the marker of choice for species identification, the unusual cytonuclear patterns in African elephants make nuclear markers more reliable. We therefore designed and utilized genetic markers for short nuclear DNA regions that contain fixed nucleotide differences between forest and savanna elephants. We used M13 forward and reverse sequences to increase the total length of PCR amplicons and to improve the quality of sequences for the target DNA. We successfully sequenced fragments of nuclear genes from dung samples of known savanna and forest elephants in the Democratic Republic of Congo, Ethiopia, and Namibia. Elephants at previously unexamined locations were found to have nucleotide character states consistent with their status as savanna or forest elephants. Using these and results from previous studies, we estimated that the short-amplicon nuclear markers could distinguish forest from savanna African elephants with more than 99% accuracy. Nuclear genotyping of museum, dung, or ivory samples will provide better-informed conservation management of Africa's elephants.

  15. Anurans in a forest remnant in the transition zone between cerrado and Atlantic Rain Forest domains in Southeastern Brazil.

    Science.gov (United States)

    Pirani, Renata M; Nascimento, Luciana B; Feio, Renato N

    2013-09-01

    This study presents the species richness, temporal distribution and reproductive activity of anurans from the Uaimií State Forest (Floresta Estadual do Uaimií - FLOE Uaimií), situated in the Quadrilátero Ferrífero region, municipality of Ouro Preto, Minas Gerais state, Brazil. Field activities were performed monthly from September 2009 to August 2010. We recorded 36 anurans species, distributed in 10 families. The greatest richness of the sampled sites corresponds to a permanent rivulet in a secondary forest. The majority of anuran species presented seasonal vocalization activity pattern, mainly in the rainy season. The anuran species composition of FLOE Uaimií is similar to others studied areas from the Quadrilátero Ferrífero region.

  16. Anurans in a forest remnant in the transition zone between cerrado and atlantic rain forest domains in southeastern Brazil

    Directory of Open Access Journals (Sweden)

    RENATA M. PIRANI

    2013-09-01

    Full Text Available This study presents the species richness, temporal distribution and reproductive activity of anurans from the Uaimií State Forest (Floresta Estadual do Uaimií – FLOE Uaimií, situated in the Quadrilátero Ferrífero region, municipality of Ouro Preto, Minas Gerais state, Brazil. Field activities were performed monthly from September 2009 to August 2010. We recorded 36 anurans species, distributed in 10 families. The greatest richness of the sampled sites corresponds to a permanent rivulet in a secondary forest. The majority of anuran species presented seasonal vocalization activity pattern, mainly in the rainy season. The anuran species composition of FLOE Uaimií is similar to others studied areas from the Quadrilátero Ferrífero region.

  17. Anurans in a forest remnant in the transition zone between cerrado and atlantic rain forest domains in southeastern Brazil

    OpenAIRE

    PIRANI,RENATA M.; Nascimento,Luciana B.; Renato N. Feio

    2013-01-01

    This study presents the species richness, temporal distribution and reproductive activity of anurans from the Uaimií State Forest (Floresta Estadual do Uaimií – FLOE Uaimií), situated in the Quadrilátero Ferrífero region, municipality of Ouro Preto, Minas Gerais state, Brazil. Field activities were performed monthly from September 2009 to August 2010. We recorded 36 anurans species, distributed in 10 families. The greatest richness of the sampled sites correspon...

  18. Biomass from the Brazilian raining forest; Biomassa das florestas amazonicas brasileiras

    Energy Technology Data Exchange (ETDEWEB)

    Fearnside, Philip M. [Instituto Nacional de Pesquisas da Amazonia (INPA), Manaus, AM (Brazil)

    1994-12-31

    This work summarizes the existing knowledge about biomass in the Brazilian area of the Amazon jungle and presents a calculation for the average total biomass in virgin forests. The results are presented. The results are higher than those presently accepted. The reasons for the discrepancy in the calculated and presently used value are presented and discussed 64 refs., 8 tabs.

  19. Leaf traits are good predictors of plant performance across 53 rain forest species

    NARCIS (Netherlands)

    Poorter, L.; Bongers, F.J.J.M.

    2006-01-01

    We compared the leaf traits and plant performance of 53 co-occurring tree species in a semi-evergreen tropical moist forest community. The species differed in all leaf traits analyzed: leaf life span varied 11-fold among species, specific leaf area 5-fold, mass-based nitrogen 3-fold, mass-based assi

  20. Four novel Talaromyces species isolated from leaf litter from Colombian Amazon rain forests

    NARCIS (Netherlands)

    Yilmaz, Neriman; López-Quintero, Carlos A.; Vasco-Palacios, Aída Marcela; Frisvad, Jens C.; Theelen, Bart; Boekhout, Teun; Samson, Robert A.; Houbraken, Jos

    2016-01-01

    Various Talaromyces strains were isolated during a survey of fungi involved in leaf litter decomposition in tropical lowland forests in the Caquetá and Amacayacu areas of the Colombian Amazon. Four new Talaromyces species are described using a polyphasic approach, which includes phenotypic character

  1. Effects of liming on forage availability and nutrient content in a forest impacted by acid rain.

    Directory of Open Access Journals (Sweden)

    Sarah E Pabian

    Full Text Available Acidic deposition and subsequent forest soil acidification and nutrient depletion can affect negatively the growth, health and nutrient content of vegetation, potentially limiting the availability and nutrient content of forage for white-tailed deer (Odocoileus virginianus and other forest herbivores. Liming is a mitigation technique that can be used to restore forest health in acidified areas, but little is known about how it affects the growth or nutrient content of deer forage. We examined the effects of dolomitic limestone application on the growth and chemical composition of understory plants in an acidified forest in central Pennsylvania, with a focus on vegetative groups included as white-tailed deer forage. We used a Before-After-Control-Impact study design with observations 1 year before liming and up to 5 years post-liming on 2 treated and 2 untreated 100-ha sites. Before liming, forage availability and several nutrients were below levels considered optimal for white-tailed deer, and many vegetative characteristics were related to soil chemistry. We observed a positive effect of liming on forb biomass, with a 2.7 fold increase on limed sites, but no biomass response in other vegetation groups. We observed positive effects of liming on calcium and magnesium content and negative effects on aluminum and manganese content of several plant groups. Responses to liming by forbs and plant nutrients show promise for improving vegetation health and forage quality and quantity for deer.

  2. Vegetation structure, logging damage and silviculture in a tropical rain forest in Suriname.

    NARCIS (Netherlands)

    Jonkers, W.B.J.

    1987-01-01

    In the first publication in this series, a polycyclic forest management system was formulated, in which three silvicultural treatments (refinements) were scheduled in a cutting cycle of twenty years. This system, which is referred to as the Celos Silvicultural System, is developed further in this st

  3. Pollen rain and pollen representation across a forest-páramo ecotone in northern Ecuador

    NARCIS (Netherlands)

    Moscol Olivera, M.; Duivenvoorden, J.F.; Hooghiemstra, H.

    2009-01-01

    Modern pollen spectra were studied in forest and páramo vegetation from the Guandera area, northern Ecuador. Pollen representation was estimated by comparing the presence of plant taxa from a recent vegetation survey with the pollen spectra in moss polsters and pollen traps. In total, 73 pollen taxa

  4. Observation of Tropical Rain Forest Trees by Airborne High-Resolution Interferometric Radar

    NARCIS (Netherlands)

    Hoekman, D.H.; Varekamp, C.

    2001-01-01

    The Indonesian Radar Experiment (INDREX) Campaign was executed in Indonesia to study the potential of high-resolution interferometric airborne radar in support of sustainable tropical forest management. Severe cloud cover limits the use of aerial photography, which is currently applied on a routine

  5. Land evaluation of valleys in a tropical rain forest area (a case study)

    NARCIS (Netherlands)

    Veldkamp, W.J.

    1979-01-01

    In the forest zone of south-western Nigeria, hydromorphic and adjacent land types are hardly used for agriculture. To determine their potential, the soils, groundwater regimes and soil moisture regimes were studied, together with the social environment, geology, hydrology, climatology and natural ve

  6. Use and management of the natural resources of the Colombian Amazon rain forest: a biological approach

    Directory of Open Access Journals (Sweden)

    Angela Yaneth Landínez Torres

    2013-12-01

    Full Text Available This study analyzes the main features associated with biological use practices and management of forest resources in the Colombian Amazon. The theoretical cut proposal contrasts biological level, the forms of appropriation of forest resources in indigenous and urban contexts depending on the importance that such activity involves the establishment of management strategies biodiversity in Colombia. In this way, provides an integrative perspective that will address conflict situations considering environmental factors not only biological but cultural in various scenarios , to give sustenance to the decisions made and provide a reasonable treatment that enables the implementation of environmental regulation mechanisms in especially in areas such as strategic biological Colombian Amazon. Finally, reflect on the importance of facilitating the functional analysis of the connections and interrelationships of ecosystem components, including human communities, sketching involving both biological and social guidelines for sustainable use of biodiversity.

  7. Observations and discussions of TanDEM-X interferogram spectra over rain forest

    OpenAIRE

    De Zan, Francesco; Krieger, Gerhard; López-Dekker, Paco

    2012-01-01

    This paper reports about some obervations over rainforest (in Brazil and Indonesia), where the spectra of TanDEM-X interferograms show distinct features, almost a signature, which is explained and modelled in terms of the scattering properties. Thanks to the comparison with simulations, the observations exclude a homogeneous, horizontally-layered forest; instead, they are compatible with a model with point scatterers clustered in clouds. Such a model, with high extinction and large gaps th...

  8. Cruising the rain forest floor: butterfly wing shape evolution and gliding in ground effect.

    Science.gov (United States)

    Cespedes, Ann; Penz, Carla M; DeVries, Philip J

    2015-05-01

    Flight is a key innovation in the evolutionary success of insects and essential to dispersal, territoriality, courtship and oviposition. Wing shape influences flight performance and selection likely acts to maximize performance for conducting essential behaviours that in turn results in the evolution of wing shape. As wing shape also contributes to fitness, optimal shapes for particular flight behaviours can be assessed with aerodynamic predictions and placed in an ecomorphological context. Butterflies in the tribe Haeterini (Nymphalidae) are conspicuous members of understorey faunas in lowland Neotropical forests. Field observations indicate that the five genera in this clade differ in flight height and behaviour: four use gliding flight at the forest floor level, and one utilizes flapping flight above the forest floor. Nonetheless, the association of ground level gliding flight behaviour and wing shape has never been investigated in this or any other butterfly group. We used landmark-based geometric morphometrics to test whether wing shapes in Haeterini and their close relatives reflected observed flight behaviours. Four genera of Haeterini and some distantly related Satyrinae showed significant correspondence between wing shape and theoretical expectations in performance trade-offs that we attribute to selection for gliding in ground effect. Forewing shape differed between sexes for all taxa, and male wing shapes were aerodynamically more efficient for gliding flight than corresponding females. This suggests selection acts differentially on male and female wing shapes, reinforcing the idea that sex-specific flight behaviours contribute to the evolution of sexual dimorphism. Our study indicates that wing shapes in Haeterini butterflies evolved in response to habitat-specific flight behaviours, namely gliding in ground effect along the forest floor, resulting in ecomorphological partitions of taxa in morphospace. The convergent flight behaviour and wing morphology

  9. Oxidant and particle photochemical processes above a south-east Asian tropical rain forest (the OP3 project: introduction, rationale, location characteristics and tools

    Directory of Open Access Journals (Sweden)

    C. N. Hewitt

    2009-09-01

    Full Text Available In April–July 2008, intensive measurements were made of atmospheric composition and chemistry in Sabah, Malaysia, as part of the "Oxidant and particle photochemical processes above a South-East Asian tropical rain forest" (OP3 project. Fluxes and concentrations of trace gases and particles were made from and above the rain forest canopy at the Bukit Atur Global Atmosphere Watch station and at the nearby Sabahmas oil palm plantation, using both ground-based and airborne measurements. Here, the measurement and modelling strategies used, the characteristics of the sites and an overview of data obtained are described. Composition measurements show that the rainforest site was not impacted by significant sources of anthropogenic pollution, and this is confirmed by satellite retrievals of NO2 and HCHO. The dominant modulators of atmospheric chemistry at the rain forest site were therefore emissions of BVOCs and soil emissions of reactive nitrogen oxides. At the observed BVOC:NOx volume mixing ratio (~104 pptv/pptv, current chemical models suggest that daytime maximum OH concentrations should be ca. 105 radicals cm−3, but observed OH concentrations were an order of magnitude greater than this. We confirm, therefore, previous measurements which suggest that an unexplained source of OH must exist above tropical forests and continue to interrogate the data to find explanations for this.

  10. Fire Patterns and Drivers of Fires in the West African Tropical Forest

    Science.gov (United States)

    Dwomoh, F. K.; Wimberly, M. C.

    2015-12-01

    The West African tropical forest (referred to as the Upper Guinean forest, UGF), is a global biodiversity hotspot providing vital ecosystem services for the region's socio-economic and environmental wellbeing. It is also one of the most fragmented and human-modified tropical forest ecosystems, with the only remaining large patches of original forests contained in protected areas. However, these remnant forests are susceptible to continued fire-mediated degradation and forest loss due to intense climatic, demographic and land use pressures. We analyzed human and climatic drivers of fire activity in the sub-region to better understand the spatial and temporal patterns of these risks. We utilized MODIS active fire and burned area products to identify fire activity within the sub-region. We measured climatic variability using TRMM rainfall data and derived indicators of human land use from a variety of geospatial datasets. We used a boosted regression trees model to determine the influences of predictor variables on fire activity. Our analyses indicated that the spatial and temporal variability of precipitation is a key driving factor of fire activity in the UGF. Anthropogenic effects on fire activity in the area were evident through the influences of agriculture and low-density populations. These human footprints in the landscape make forests more susceptible to fires through forest fragmentation, degradation, and fire spread from agricultural areas. Forested protected areas within the forest savanna mosaic experienced frequent fires, whereas the more humid forest areas located in the south and south-western portions of the study area had fewer fires as these rainforests tend to offer some buffering against fire encroachment. These results improve characterization of UGF fire regime and expand our understanding of the spatio-temporal dynamics of tropical forest fires in response to human and climatic pressures.

  11. The Tropical Ecology, Assessment and Monitoring (TEAM) Network: An early warning system for tropical rain forests.

    Science.gov (United States)

    Rovero, Francesco; Ahumada, Jorge

    2017-01-01

    While there are well established early warning systems for a number of natural phenomena (e.g. earthquakes, catastrophic fires, tsunamis), we do not have an early warning system for biodiversity. Yet, we are losing species at an unprecedented rate, and this especially occurs in tropical rainforests, the biologically richest but most eroded biome on earth. Unfortunately, there is a chronic gap in standardized and pan-tropical data in tropical forests, affecting our capacity to monitor changes and anticipate future scenarios. The Tropical Ecology, Assessment and Monitoring (TEAM) Network was established to contribute addressing this issue, as it generates real time data to monitor long-term trends in tropical biodiversity and guide conservation practice. We present the Network and focus primarily on the Terrestrial Vertebrates protocol, that uses systematic camera trapping to detect forest mammals and birds, and secondarily on the Zone of Interaction protocol, that measures changes in the anthroposphere around the core monitoring area. With over 3 million images so far recorded, and managed using advanced information technology, TEAM has created the most important data set on tropical forest mammals globally. We provide examples of site-specific and global analyses that, combined with data on anthropogenic disturbance collected in the larger ecosystem where monitoring sites are, allowed us to understand the drivers of changes of target species and communities in space and time. We discuss the potential of this system as a candidate model towards setting up an early warning system that can effectively anticipate changes in coupled human-natural system, trigger management actions, and hence decrease the gap between research and management responses. In turn, TEAM produces robust biodiversity indicators that meet the requirements set by global policies such as the Aichi Biodiversity Targets. Standardization in data collection and public sharing of data in near real time

  12. Measurements of soil and canopy exchange rates in the Amazon rain forest using Rn-222

    Science.gov (United States)

    Trumbore, S. E.; Keller, M.; Wofsy, S. C.; Da Costa, J. M.

    1990-01-01

    Measurements were taken of the emission of Rn-222 from Amazon forest rocks and soils and used as a tracer of ventilation of the forest canopy layer at night. It was determined that the greatest resistance to transfer of trace gases from the soil to the atmosphere lies in the soil air space. Profiles of Rn-222 and CO2 showed steepest concentration gradients in the layer between 0 and 3 m above soil surface. Aerodynamic resistances calculated for this layer from Rn-222 and CO2 varied from 1.6 to 18 s/cm, with greater resistance during the afternoon than at night. The resistance to exchange with air from the entire 41 m layer below the canopy averaged 4.8 s/cm during 13 nights of CO2 profiles. The calculated average time to flush the layer below 41 m is 5.5 hr, and it is concluded that this indicates that significant exchange occurs despite nocturnal stratification.

  13. Importance of terrestrial arthropods as subsidies in lowland Neotropical rain forest stream ecosystems

    Science.gov (United States)

    Small, Gaston E.; Torres, Pedro J.; Schwizer, Lauren M.; Duff, John H.; Pringle, Catherine M.

    2013-01-01

    The importance of terrestrial arthropods has been documented in temperate stream ecosystems, but little is known about the magnitude of these inputs in tropical streams. Terrestrial arthropods falling from the canopy of tropical forests may be an important subsidy to tropical stream food webs and could also represent an important flux of nitrogen (N) and phosphorus (P) in nutrient-poor headwater streams. We quantified input rates of terrestrial insects in eight streams draining lowland tropical wet forest in Costa Rica. In two focal headwater streams, we also measured capture efficiency by the fish assemblage and quantified terrestrially derived N- and P-excretion relative to stream nutrient uptake rates. Average input rates of terrestrial insects ranged from 5 to 41 mg dry mass/m2/d, exceeding previous measurements of aquatic invertebrate secondary production in these study streams, and were relatively consistent year-round, in contrast to values reported in temperate streams. Terrestrial insects accounted for half of the diet of the dominant fish species, Priapicthys annectens. Although terrestrially derived fish excretion was found to be a small flux relative to measured nutrient uptake rates in the focal streams, the efficient capture and processing of terrestrial arthropods by fish made these nutrients available to the local stream ecosystem. This aquatic-terrestrial linkage is likely being decoupled by deforestation in many tropical regions, with largely unknown but potentially important ecological consequences.

  14. Effects of calcium on seed germination, seedling growth and photosynthesis of six forest tree species under simulated acid rain.

    Science.gov (United States)

    Liu, Ting-Wu; Wu, Fei-Hua; Wang, Wen-Hua; Chen, Juan; Li, Zhen-Ji; Dong, Xue-Jun; Patton, Janet; Pei, Zhen-Ming; Zheng, Hai-Lei

    2011-04-01

    We selected six tree species, Pinus massoniana Lamb., Cryptomeria fortunei Hooibr. ex Otto et Dietr., Cunninghamia lanceolata (Lamb.) Hook., Liquidambar formosana Hance, Pinus armandii Franch. and Castanopsis chinensis Hance, which are widely distributed as dominant species in the forest of southern China where acid deposition is becoming more and more serious in recent years. We investigated the effects and potential interactions between simulated acid rain (SiAR) and three calcium (Ca) levels on seed germination, radicle length, seedling growth, chlorophyll content, photosynthesis and Ca content in leaves of these six species. We found that the six species showed different responses to SiAR and different Ca levels. Pinus armandii and C. chinensis were very tolerant to SiAR, whereas the others were more sensitive. The results of significant SiAR × Ca interactions on different physiological parameters of the six species demonstrate that additional Ca had a dramatic rescue effect on the seed germination and seedling growth for the sensitive species under SiAR. Altogether, we conclude that the negative effects of SiAR on seed germination, seedling growth and photosynthesis of the four sensitive species could be ameliorated by Ca addition. In contrast, the physiological processes of the two tolerant species were much less affected by both SiAR and Ca treatments. This conclusion implies that the degree of forest decline caused by long-term acid deposition may be attributed not only to the sensitivity of tree species to acid deposition, but also to the Ca level in the soil.

  15. Effects of land clearing techniques and tillage systems on runoff and soil erosion in a tropical rain forest in Nigeria.

    Science.gov (United States)

    Ehigiator, O A; Anyata, B U

    2011-11-01

    This work reports runoff and soil loss from each of 14 sub-watersheds in a secondary rain forest in south-western Nigeria. The impact of methods of land clearing and post-clearing management on runoff and soil erosion under the secondary forest is evaluated. These data were acquired eighteen years after the deforestation of primary vegetation during the ' West bank' project of the International Institute for Tropical Agriculture (IITA). These data are presented separately for each season; however, statistical analyses for replicates were not conducted due to differences in their past management. Soil erosion was affected by land clearing and tillage methods. The maximum soil erosion was observed on sub-watersheds that were mechanically cleared with tree-pusher/root-rake attachments and tilled conventionally. A high rate of erosion was observed even when graded-channel terraces were constructed to minimize soil erosion. In general there was much less soil erosion on manually cleared than on mechanically cleared sub-watersheds (2.5 t ha(-1) yr(-1) versus 13.8 t ha(-1) yr(-1)) and from the application of no-tillage methods than from conventionally plowed areas (6.5 t ha(-1) yr(-1) versus 12.1 t ha(-1) yr(-1)). The data indicate that tillage methods and appropriate management of soils and crops play an important role in soil and water conservation and in decreasing the rate of decline of soil quality.

  16. Present-day central African forest is a legacy of the 19th century human history

    Science.gov (United States)

    Morin-Rivat, Julie; Fayolle, Adeline; Favier, Charly; Bremond, Laurent; Gourlet-Fleury, Sylvie; Bayol, Nicolas; Lejeune, Philippe; Beeckman, Hans; Doucet, Jean-Louis

    2017-01-01

    The populations of light-demanding trees that dominate the canopy of central African forests are now aging. Here, we show that the lack of regeneration of these populations began ca. 165 ya (around 1850) after major anthropogenic disturbances ceased. Since 1885, less itinerancy and disturbance in the forest has occurred because the colonial administrations concentrated people and villages along the primary communication axes. Local populations formerly gardened the forest by creating scattered openings, which were sufficiently large for the establishment of light-demanding trees. Currently, common logging operations do not create suitable openings for the regeneration of these species, whereas deforestation degrades landscapes. Using an interdisciplinary approach, which included paleoecological, archaeological, historical, and dendrological data, we highlight the long-term history of human activities across central African forests and assess the contribution of these activities to present-day forest structure and composition. The conclusions of this sobering analysis present challenges to current silvicultural practices and to those of the future. DOI: http://dx.doi.org/10.7554/eLife.20343.001 PMID:28093097

  17. Forest gradients in West Africa. A spatial gradient analysis.

    NARCIS (Netherlands)

    Rompaey, van R.S.A.R.

    1993-01-01

    The tropical rain forests of West Africa, west of the Dahomey interval, once covered some 40 million ha. Being on the western fringe of the African continent, they receive abundant rainfall from the SW monsoon. Further inland, rainfall gradually decreases and the forests give way to savanna and ulti

  18. Horizontal stratification of the sand fly fauna (Diptera: Psychodidae in a transitional vegetation between caatinga and tropical rain forest, state of Bahia, Brazil

    Directory of Open Access Journals (Sweden)

    Dias-Lima Artur Gomes

    2003-01-01

    Full Text Available A study about the horizontal stratification of the sand fly fauna in two distinct ecosystems, caatinga area, endemic for visceral leishmaniasis, and the tropical rain forest area, endemic for cutaneous leishmaniasis, was performed in the state of Bahia, Brazil. Lutzomyia longipalpis was predominant in the caatinga, and following it came the species L. capixaba and L. oswaldoi. In the tropical rain forest other species were found, such as L. intermedia, L. migonei, L. whitmani, L. yuilli, L.fischeri, L. damascenoi, L. evandroi, L. monticola, and L. lenti. It was found that the geographical limits of the vector species of visceral and cutaneous leishmaniasis are clearly defined by the biological and phytogeographic characteristics.

  19. A forensic entomology case from the Amazon rain forest of Brazil.

    Science.gov (United States)

    Pujol-Luz, José R; Marques, Helder; Ururahy-Rodrigues, Alexandre; Rafael, José Albertino; Santana, Fernando H A; Arantes, Luciano C; Constantino, Reginaldo

    2006-09-01

    The first case of application of forensic entomology in the Brazilian Amazonia is described. The corpses of 26 men were found in the rainforest in Rondonia State, Brazil. Fly larvae collected on the bodies during autopsy were identified as Paralucilia fulvinota (Diptera, Calliphoridae). No data or specimens were collected at the crime scene. At the laboratory, the larvae developed into pupae in 58 h and into adults in 110.5 h. The total development time for P. fulvinota was measured in field experiments inside the forest. The age of the larvae when collected from the bodies was estimated as the difference between the time required for them to become adults and the total development time for this species. The estimated age of the maggots and the minimum postmortem interval was 5.7 days.

  20. Climate affects the structure of mixed rain forest in southern sector of Atlantic domain in Brazil

    Science.gov (United States)

    Sevegnani, Lucia; Uhlmann, Alexandre; Gasper, André Luís de; Meyer, Leila; Vibrans, Alexander Christian

    2016-11-01

    This study aimed to analyze the influence of environmental factors in determining the variation in forest structure. We obtained the data through sampling units placed regularly in a grid of 10 km × 10 km in the state of Santa Catarina, southern Brazil. The axes of Detendred Correspondence Analysis summarized the vegetation structure and we used these as response variables in ordinary least square models, and environmental variables as predictors. Moran Eigenvector Maps were used as spatial predictors, enabling the variance partitioning. The results revealed influence of climatic factors, especially thermal and rainfall in determining the vegetation structure. The physical geography (high plateaus) and positioning below the Tropic of Capricorn line are the main static elements influencing the climate and therefore the vegetation.

  1. Acid rain and forest decline. 3. rev. ed. Saurer Regen und Waldsterben; Unterrichtsmaterialien

    Energy Technology Data Exchange (ETDEWEB)

    Kues, J.; Matzner, E.; Murach, D.; Blanck, K.

    1991-01-01

    These materials for sixth-form education and adult education provide information on emissions of SO[sub 2], NO[sub x] and heavy metals and their propagtaion, as well as on the formation of oxidants and other chemical conversion processes in the atmosphere. The pathway of the pollutants is followed up, via their atmospheric transport in their deposition on plants and soil, including forms and rates of deposition, and further to their direct and indirect effects on forest ecosystems and their elements. Effects on leaves, buffering of acids and soil acidification, and hazards to ground water are described; the physiological consequences of heavy-metal release in soil on roots and overground organs are explained. The kinetic of the effect of pollutants is followed up and its interaction with other stress factors discussed. Finally, suitable counter-measures are presented. (UWA)

  2. Variation in photosynthetic photon flux density within a tropical seasonal rain forest of Xishuangbanna, south-western China

    Institute of Scientific and Technical Information of China (English)

    DOU Jun-xia; ZHANG Yi-ping; FENG Zong-wei; LIU Wen-jie

    2005-01-01

    The effects of canopy development, solar angle, and weather conditions on temporal variation in photosynthetic photon flux density(PPFD) at three heights within a tropical rain forest canopy in Xishuangbanna, China, were examined. PPFD was measured every second and stored as 10-min averages from 1 December 2002 to 30 November 2003. PPFD variability was examined at three different tempcral scales. Specific days in March, September, and December with clear and overcast sky conditions were selected to separate the effects of leaf area index(LAI) and solar angle on diumal variability. On both clear and overcast days, mean daily average PPFD was significantly different between March and September at all heights, except 10 m on clear days, suggesting that LAI directly influences PPFD. In contrast, the differences in daily average PPFD among three heights between September and December were likely due to variation in solar angle. In addition, daily average PPFD at all locations were significantly lower under overcast than clear sky conditions in March, September and December. Over the year-long study, the mean daily total PPFD at 21 m, 10 m and 4 m was 2.8, 2.7 and 0.7mean daily total PPFD occurred at the same heights among different seasons, and diurnal, day-to-day and seasonal PPFD varied at different heights within the canopy. The possible effects of light variability on physiological and morphological responses of plants are discussed.

  3. Composition of soil testate amoebae communities: their structure and modifications in the temperate rain forests of New Zealand and Tasmania.

    Science.gov (United States)

    Bamforth, Stuart S

    2015-01-01

    A study of the temperate rain forests of New Zealand and Tasmania showed that their soil testate amoebae communities are composed of five groups of taxa: (1) seven taxa characteristic of wet acidic soils and Sphagnum peatlands (i.e., Amphitemidae, Apodera, Alcodera, Certesella, Cyphoderia, Placocista); (2) a group of 16 species of predatory Nebelids and Heleopera spp., characteristic of Sphagnum and rainforests; (3) a group of 17 species of litter and soil Euglypha, excluding the smallest ones; (4) a diverse population of other morphotypes common in other biomes; and (5) a population of small euryoecious taxa - Cryptodifflugia and Pseudodifflugia spp., Euglypha rotunda, E. laevis, Corythion and Trinema spp. This fifth group, with other r-selected protists (e.g., colpodid ciliates) appears in all habitats. Soil testate communities of other rainforests are composed of the same five groups and are distinguished by the first three assemblages. The fourth and fifth groups, often supplemented with a few Euglypha species, comprise the soil testate amoebae of other biomes. Nebelids and Heleopera, incorporating prey idiosomes into their shells, add an additional link to the role of Euglyphids in the silica cycle. Three Gondwanan Nebelid genera, Apodera, Alcodera, and Certesella were frequently observed, and the discovery of Alcodera cockayni in Tasmania extends its recorded distribution in the Southern Hemisphere.

  4. 酸雨对林木伤害研究综述%Research Review of the Harm of Acid Rain on Forest Woods

    Institute of Scientific and Technical Information of China (English)

    代永刚; 宋鹏; 冯毅; 鲁洋

    2011-01-01

    Based on the research of acid rain, the formation and distribution of acid rain are elaborated. Acid rain which is a great harm to the ecosystem, human health and materials is a global environmental problem. The study and achievements on the acid rain injury to forest trees were reviewed from three major aspects, such as the injury to metabolism function, growth and development and wood characteristics. Several disruptive problems which should be emphasized in our later acid rain research were proposed.%文章从酸雨的研究历史出发,阐述了酸雨的形成和分布,指出酸雨是一种全球性的环境问题;从酸雨污染对林木代谢功能、生长发育、木材特性这三大方面综述了国内外在酸雨给林木造成伤害方面的研究动态及其成果,并提出了在今后酸雨研究中应该重视的几大突破性问题。

  5. Effects of simulated acid rain on soil respiration and its components in a subtropical mixed conifer and broadleaf forest in southern China.

    Science.gov (United States)

    Liang, Guohua; Hui, Dafeng; Wu, Xiaoying; Wu, Jianping; Liu, Juxiu; Zhou, Guoyi; Zhang, Deqiang

    2016-02-01

    Soil respiration is a major pathway in the global carbon cycle and its response to environmental changes is an increasing concern. Here we explored how total soil respiration (RT) and its components respond to elevated acid rain in a mixed conifer and broadleaf forest, one of the major forest types in southern China. RT was measured twice a month in the first year under four treatment levels of simulated acid rain (SAR: CK, the local lake water, pH 4.7; T1, water pH 4.0; T2, water pH 3.25; and T3, water pH 2.5), and in the second year, RT, litter-free soil respiration (RS), and litter respiration (RL) were measured simultaneously. The results indicated that the mean rate of RT was 2.84 ± 0.20 μmol CO2 m(-2) s(-1) in the CK plots, and RS and RL contributed 60.7% and 39.3% to RT, respectively. SAR marginally reduced (P = 0.08) RT in the first year, but significantly reduced RT and its two components in the second year (P acid rain, the decline trend of RT in the forests in southern China appears to be attributable to the decline of soil respiration in the litter layer.

  6. Measurements of reactive chlorocarbons over the Surinam tropical rain forest: indications for strong biogenic emissions

    Directory of Open Access Journals (Sweden)

    H. A. Scheeren

    2003-10-01

    Full Text Available Contrary to the understanding of the emissions and chemical behavior of halocarbons from anthropogenic sources (e.g. CFCs and HCFCs, the biogeochemistry of naturally emitted halocarbons is still poorly understood. We present measurements of chloromethane (methyl chloride, CH3Cl, trichloromethane (chloroform, CHCl3, dichloromethane (CH2Cl2, and tetrachloroethylene (C2Cl4 from air samples taken over the Surinam rainforest during the 1998 LBA/CLAIRE campaign. The samples were collected in stainless steel canisters on-board a Cessna Citation jet aircraft and analyzed in the laboratory using a gas chromatograph equipped with FID and ECD. The chlorocarbons we studied have atmospheric lifetimes of ~1 year or less, and appear to have significant emissions from natural sources including oceans, soils and vegetations, as well as biomass burning. These sources are primarily concentrated in the tropics (30º N-30º S. We detected an increase as a function of latitude of methyl chloride, chloroform, and tetrachloroethylene mixing ratios, in pristine air masses advected from the Atlantic Ocean toward the central Amazon. In the absence of significant biomass burning sources, we attribute this increase to biogenic emissions from the Surinam rainforest. From our measurements, we deduce fluxes from the Surinam rainforest of 7.6±1.8 μg CH3Cl m−2 h−1, 1.11±0.08g CHCl3 μm−2 h−1, and 0.36±0.07 μg C2Cl4 m−2 h−1. Extrapolated to a global scale, our emission estimates suggest a large potential source of 2 Tg CH3Cl yr−1 from tropical forests, which could account for the net budget discrepancy (underestimation of sources, as indicated previously. In addition, our estimates suggest a potential emission of 57±17,Gg C2C4 yr−1

  7. Rebuilding after collapse: evidence for long-term cohort dynamics in the native Hawaiian rain forest

    Science.gov (United States)

    Boehmer, Hans Juergen; Wagner, Helene H.; Jacobi, James D.; Gerrish, Grant C.; Mueller-Dombois, Dieter

    2013-01-01

    Questions: Do long-term observations in permanent plots confirm the conceptual model of Metrosideros polymorpha cohort dynamics as postulated in 1987? Do regeneration patterns occur independently of substrate age, i.e. of direct volcanic disturbance impact? Location: The windward mountain slopes of the younger Mauna Loa and the older Mauna Kea volcanoes (island of Hawaii, USA). Methods: After widespread forest decline (dieback), permanent plots were established in 1976 in 13 dieback and 13 non-dieback patches to monitor the population structure of M. polymorpha at ca. 5-yr intervals. Within each plot of 20 × 20 m, all trees with DBH >2.5 cm were individually tagged, measured and tree vigour assessed; regeneration was quantified in 16 systematically placed subplots of 3 × 5 m. Data collected in the subplots included the total number of M. polymorpha seedlings and saplings (five stem height classes). Here we analyse monitoring data from six time steps from 1976 to 2003 using repeated measures ANOVA to test specific predictions derived from the 1987 conceptual model. Results: Regeneration was significantly different between dieback and non-dieback plots. In dieback plots, the collapse in the 1970s was followed by a ‘sapling wave’ that by 2003 led to new cohort stands of M. polymorpha. In non-dieback stands, seedling emergence did not result in sapling waves over the same period. Instead, a ‘sapling gap’ (i.e. very few or no M. polymorpha saplings) prevailed as typical for mature stands. Canopy dieback in 1976, degree of recovery by 2003 and the number of living trees in 2003 were unrelated to substrate age. Conclusions: Population development of M. polymorpha supports the cohort dynamics model, which predicts rebuilding of the forest with the same canopy species after dieback. The lack of association with substrate age suggests that the long-term maintenance of cohort structure in M. polymorpha does not depend on volcanic disturbance but may be related to

  8. Airborne and spaceborne radar images for geologic and environmental mapping in the Amazon rain forest, Brazil

    Science.gov (United States)

    Ford, John P.; Hurtak, James J.

    1986-01-01

    Spaceborne and airborne radar image of portions of the Middle and Upper Amazon basin in the state of Amazonas and the Territory of Roraima are compared for purposes of geological and environmental mapping. The contrasted illumination geometries and imaging parameters are related to terrain slope and surface roughness characteristics for corresponding areas that were covered by each of the radar imaging systems. Landforms range from deeply dissected mountain and plateau with relief up to 500 m in Roraima, revealing ancient layered rocks through folded residual mountains to deeply beveled pediplain in Amazonas. Geomorphic features provide distinct textural signatures that are characteristic of different rock associations. The principle drainages in the areas covered are the Rio Negro, Rio Branco, and the Rio Japura. Shadowing effects and low radar sensitivity to subtle linear fractures that are aligned parallel or nearly parallel to the direction of radar illumination illustrate the need to obtain multiple coverage with viewing directions about 90 degrees. Perception of standing water and alluvial forest in floodplains varies with incident angle and with season. Multitemporal data sets acquired over periods of years provide an ideal method of monitoring environmental changes.

  9. Diet and feeding behaviour of Indri indri in a low-altitude rain forest.

    Science.gov (United States)

    Britt, Adam; Randriamandratonirina, Nicolas J; Glasscock, Kellie D; Iambana, Bernard R

    2002-01-01

    The diet and feeding behaviour of Indri indri were investigated in the Betampona Reserve, eastern Madagascar, over 12 months from February 2000 to February 2001. The highly folivorous diet of this species was confirmed--feeding on foliage (leaves and petioles) accounting for 82% of feeding records. Immature leaves were the preferred dietary item, but at times of relative scarcity mature leaves, fruit, seeds, flowers and bark were substituted. The indri were observed to feed on parts from 22 plant families, 37 genera and at least 42 species. The most important plant families in the diet of Indri were Lauraceae, Clusiaceae and Myristicaceae. Most feeding at Betampona was observed at 5-20 m above the forest floor amongst small (2.1-5.0 cm), oblique/horizontal supports (0-45 degrees). The indri spent 41.4% of their active period feeding most commonly in above-branch postures. Studies such as this are important for the development of conservation management plans for this endangered species.

  10. PRECIPITATION EFFECTS ON SOIL CHARACTERISTICS IN TROPICAL RAIN FORESTS OF THE CHOCO BIOGEOGRAPHICAL REGION

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    Harley Quinto Mosquera

    2016-01-01

    Full Text Available Average annual precipitation (AAP is one of the principal environmental factors that regulates processes in terrestrial ecosystems. The effect of AAP on the availability of edaphic nutrients is poorly understood, especially in tropical zones with high rainfall. In order to evaluate the effects of high AAP on the availability of soil N, P, and K, physicochemical parameters were measured in soils of three tropical rainforests in the Chocó biogeographical region with different AAPs (7,500, 8,000, and 10,000 mm yr-1. Furthermore, a bibliographical review was carried out that including studies for distinct tropical Ultisols and AAP ranging from 1,800 to 10,000 mm yr-1. The evaluated soils presented extreme acidity with high contents of Al, organic matter (OM and total N, and low quantities of P, Mg, and Ca. The K concentrations were intermediate and the effective cation exchange capacity (ECEC was low. On the other hand, in the evaluation of the influence of the AAP on the availability of N, P, and K in the soil, contrasting tendencies were observed. On one side, a positive curvilinear relationship was found between the availability of N and the increase in the AAP. On the other side, the available P content significantly decreased with increasing AAP. In conclusion, the excessive AAP resulted in increases in total N and low availability of P, thereby altering the dynamics of the nutrients and the carbon balance of the tropical forest

  11. The African rain forest during the Last Glacial Maximum an archipelago of forests in a sea of grass

    NARCIS (Netherlands)

    Leal, M.E.

    2004-01-01

    In centralGabon(

  12. Biological screening of rain forest plot trees from Palawan Island (Philippines).

    Science.gov (United States)

    Horgen, F D; Edrada, R A; de los Reyes, G; Agcaoili, F; Madulid, D A; Wongpanich, V; Angerhofer, C K; Pezzuto, J M; Soejarto, D D; Farnsworth, N R

    2001-01-01

    Study plots totaling 0.2 Ha were established in primary forest in the highlands of central Palawan Island, Philippines. Samples of various anatomical parts [typically leaf + twig (If/tw), stem bark (sb), and root (rt)] were collected from all tree species represented within the plots by individuals having a diameter at breast height > or = 10 cm. In all, 211 distinct samples were obtained from 68 tree species, representing 35 families (not including samples from 4 indeterminate species). Methanol extracts of these samples were tested in in vitro antiplasmodial, brine shrimp toxicity, and cytotoxicity assays. The following samples showed an IC50 Meliosma pinnata ssp. macrophylla (lf/tw, rt), Myristica guatteriifolia (lf/tw), Ochrosia glomerata (rt, sb), Swintonia foxworthyi (lf/tw), Syzygium sp. 1 (rt), Turpinia pomifera (rt), and Xanthophyllum flavescens (sb). Secondly, those samples which displayed > or = 50% immobilization of brine shrimp at 100 microg/mL were: Acronychia laurifolia (lf/tw/fruit, rt, sb), Agathis celebica (lf/tw, sb), Aglaia sp. 1 (lf/tw), Alphonsea sp. 1 (rt), Ardisia iwahigensis (lf/tw), Arthrophyllum ahernianum (lf/tw, rt, sb), Castanopsis cf. evansii (rt), Cinnamomum griffithii (lf/tw, rt), Croton argyratus (lf/tw), C. leiophyllus (lf/tw, rt), Dysoxylum cauliflorum (fruit, lf/tw, rt), Euonymus javanicus (rt), Glochidion sp. 1 (rt), Polyosma sp. 1 (rt), Symplocos polyandra (rt), Timonius gammillii (sb), and Xanthophyllum flavescens (rt). Lastly, samples which exhibited an IC50 < or = 20 microg/mL against one or more of the cancer cell lines employed (LU1, KB, KB-V1, P-388, LNCaP, or ZR-75-1) include: Acronychia laurifolia (lf/tw/fruit, rt, sb), Aglaia sp. 1 (sb), Aglaia sp. 2 (rt), Alphonsea sp. 1 (rt), Ardisia iwahigensis (lf/tw, rt, sb), Astronia cumingiana (sb), Croton argyratus (lf/tw, rt, sb), C. leiophyllus (lf/tw, rt), Dimorphocalyx murina (lf/tw, rt, sb), Lithocarpus caudatifolius (rt, sb), Litsea cf. sibuyanensis (rt), Syzygium cf

  13. Coupled carbon-water exchange of the Amazon rain forest, I. Model description, parameterization and sensitivity analysis

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    E. Simon

    2005-04-01

    Full Text Available Detailed one-dimensional multilayer biosphere-atmosphere models, also referred to as CANVEG models, are used for more than a decade to describe coupled water-carbon exchange between the terrestrial vegetation and the lower atmosphere. Within the present study, a modified CANVEG scheme is described. A generic parameterization and characterization of biophysical properties of Amazon rain forest canopies is inferred using available field measurements of canopy structure, in-canopy profiles of horizontal wind speed and radiation, canopy albedo, soil heat flux and soil respiration, photosynthetic capacity and leaf nitrogen as well as leaf level enclosure measurements made on sunlit and shaded branches of several Amazonian tree species during the wet and dry season. The sensitivity of calculated canopy energy and CO2 fluxes to the uncertainty of individual parameter values is assessed. In the companion paper, the predicted seasonal exchange of energy, CO2, ozone and isoprene is compared to observations.

    A bi-modal distribution of leaf area density with a total leaf area index of 6 is inferred from several observations in Amazonia. Predicted light attenuation within the canopy agrees reasonably well with observations made at different field sites. A comparison of predicted and observed canopy albedo shows a high model sensitivity to the leaf optical parameters for near-infrared short-wave radiation (NIR. The predictions agree much better with observations when the leaf reflectance and transmission coefficients for NIR are reduced by 25–40%. Available vertical distributions of photosynthetic capacity and leaf nitrogen concentration suggest a low but significant light acclimation of the rain forest canopy that scales nearly linearly with accumulated leaf area.

    Evaluation of the biochemical leaf model, using the enclosure measurements, showed that recommended parameter

  14. Natural regeneration in a quaternary coastal plain in southern Brazilian Atlantic Rain forest

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    Cleber Ibraim Salimon

    2001-06-01

    Full Text Available Composition, structure and dynamics of an eight year old secondary forest was studied at Reserva Volta Velha (26°04'S; 48°38'W, southern Brazil. A 0.72ha plot was divided into 36 subplots of 20X10m, where all trees/shrubs greater than 1m tall were identified, measured (height/diameter and evaluated (successional status. The results were: (1 95 species collected within 68 genera and 44 families; the most species rich families were Myrtaceae and Asteraceae with 8 species each; (2 the most important species (considering biomass and density were Psidium cattleianum, Eupatorium casarettoi, Ocotea pulchella and Ternstroemia brasiliensis; (3 the most similar area was a fallow abandoned 35 years ago; (4 the higher species diversity were found in border subplots, indicating that most of the species do not tolerate extreme conditions in the center of the opening, and are colonizing the area through the borders.A maior parte das áreas florestais no domínio da Floresta Atlântica se encontra degradada devido a diferentes pressões antrópicas. No intuito de ampliar os conhecimentos sobre relictos de florestas nativas intactas, e também de áreas abandonadas para se obter dados sobre os processos naturais de regeneração, foi realizado um estudo da composição florística, estrutura e dinâmica de uma comunidade vegetal em estágio seral inicial de 8 anos. em Floresta Ombrófila Densa das Terras Baixas, na Reserva Volta Velha, Itapoa-SC, Brasil. Foram utilizados os métodos usuais de coleta, herborização e identificação das espécies encontradas, e a análise estrutural foi feita utilizando-se 36 parcelas retangulares de 20 X 10m, sendo incluídas todas as plantas arbustivo/arbóreas com no mínimo 1 metro de altura. Os resultados obtidos foram os seguintes: 1- Foram encontradas 96 espécies, dentro de 68 gêneros e 44 famílias; as famílias com maior número de espécies foram Myrtaceae e Asteraceae com 8 espécies cada, e o gênero mais

  15. Functional trait trade-offs for the tropical montane rain forest species responding to light from simulating experiments.

    Science.gov (United States)

    Mao, Peili; Zang, Runguo; Shao, Hongbo; Yu, Junbao

    2014-01-01

    Differences among tropical tree species in survival and growth to light play a key role in plant competition and community composition. Two canopy species with contrasting functional traits dominating early and late successional stages, respectively, in a tropical montane rain forest of Hainan Island, China, were selected in a pot experiment under 4 levels of light intensity (full, 50%, 30%, and 10%) in order to explore the adaptive strategies of tropical trees to light conditions. Under each light intensity level, the pioneer species, Endospermum chinense (Euphorbiaceae), had higher relative growth rate (RGR), stem mass ratio (SMR), specific leaf area (SLA), and morphological plasticity while the shade tolerant climax species, Parakmeria lotungensis (Magnoliaceae), had higher root mass ratio (RMR) and leaf mass ratio (LMR). RGR of both species was positively related to SMR and SLA under each light level but was negatively correlated with RMR under lower light (30% and 10% full light). The climax species increased its survival by a conservative resource use strategy through increasing leaf defense and root biomass investment at the expense of growth rate in low light. In contrast, the pioneer increased its growth by an exploitative resource use strategy through increasing leaf photosynthetic capacity and stem biomass investment at the expense of survival under low light. There was a trade-off between growth and survival for species under different light conditions. Our study suggests that tree species in the tropical rainforest adopt different strategies in stands of different successional stages. Species in the earlier successional stages have functional traits more advantageous to grow faster in the high light conditions, whereas species in the late successional stages have traits more favorable to survive in the low light conditions.

  16. Seasonal patterns of leaf gas exchange and water relations in dry rain forest trees of contrasting leaf phenology.

    Science.gov (United States)

    Choat, Brendan; Ball, Marilyn C; Luly, Jon G; Donnelly, Christine F; Holtum, Joseph A M

    2006-05-01

    Diurnal and seasonal patterns of leaf gas exchange and water relations were examined in tree species of contrasting leaf phenology growing in a seasonally dry tropical rain forest in north-eastern Australia. Two drought-deciduous species, Brachychiton australis (Schott and Endl.) A. Terracc. and Cochlospermum gillivraei Benth., and two evergreen species, Alphitonia excelsa (Fenzal) Benth. and Austromyrtus bidwillii (Benth.) Burret. were studied. The deciduous species had higher specific leaf areas and maximum photosynthetic rates per leaf dry mass in the wet season than the evergreens. During the transition from wet season to dry season, total canopy area was reduced by 70-90% in the deciduous species and stomatal conductance (g(s)) and assimilation rate (A) were markedly lower in the remaining leaves. Deciduous species maintained daytime leaf water potentials (Psi(L)) at close to or above wet season values by a combination of stomatal regulation and reduction in leaf area. Thus, the timing of leaf drop in deciduous species was not associated with large negative values of daytime Psi(L) (greater than -1.6 MPa) or predawn Psi(L) (greater than -1.0 MPa). The deciduous species appeared sensitive to small perturbations in soil and leaf water status that signalled the onset of drought. The evergreen species were less sensitive to the onset of drought and g(s) values were not significantly lower during the transitional period. In the dry season, the evergreen species maintained their canopies despite increasing water-stress; however, unlike Eucalyptus species from northern Australian savannas, A and g(s) were significantly lower than wet season values.

  17. Anti-Streptococcal activity of Brazilian Amazon Rain Forest plant extracts presents potential for preventive strategies against dental caries

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    Juliana Paola Corrêa da SILVA

    2014-04-01

    Full Text Available Caries is a global public health problem, whose control requires the introduction of low-cost treatments, such as strong prevention strategies, minimally invasive techniques and chemical prevention agents. Nature plays an important role as a source of new antibacterial substances that can be used in the prevention of caries, and Brazil is the richest country in terms of biodiversity. Objective: In this study, the disk diffusion method (DDM was used to screen over 2,000 Brazilian Amazon plant extracts against Streptococcus mutans. Material and Methods: Seventeen active plant extracts were identified and fractionated. Extracts and their fractions, obtained by liquid-liquid partition, were tested in the DDM assay and in the microdilution broth assay (MBA to determine their minimal inhibitory concentrations (MICs and minimal bactericidal concentrations (MBCs. The extracts were also subjected to antioxidant analysis by thin layer chromatography. Results: EB271, obtained from Casearia spruceana, showed significant activity against the bacterium in the DDM assay (20.67±0.52 mm, as did EB1129, obtained from Psychotria sp. (Rubiaceae (15.04±2.29 mm. EB1493, obtained from Ipomoea alba, was the only extract to show strong activity against Streptococcus mutans (0.08 mg/mLrain forest, show potential as sources of new antibacterial agents for use as chemical coadjuvants in prevention strategies to treat caries.

  18. Fluxes of CH4 and N2O from soil under a tropical seasonal rain forest in Xishuangbanna, Southwest China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    CH4 and N2O fluxes from soil under a tropical seasonal rain forest in Xishuangbanna, Southwest China were measured for one year using closed static chamber technique and gas chromatography method. Three treatments were set in the studied field: (A) litter-free,(B) with litter, and (C) with litter and seedling. The results showed that the soil in our study was a sink of atmospheric CH4 and source of atmospheric N2O. The observed mean CH4 fluxes from treatments A, B, and C were -50.0±4.0, -35.9±2.8,-31.6±2.8 μgC/(m2·h),respectively,and calculated annual fluxes in2003 were -4.1,-3.1,and -2.9kgC/hm2,respectively.The observed mean N2O fluxes from treatments A,B,and C were 30.9±3.1,28.2±3.5,50.2±3.7μgN/(m2·h),respectively,and calculated annual fluxes in 2003 were 2.8, 2.6, and 3.7 kgN/hm2, respectively. Seasonal variations in CH4 and N2O fluxes were significant among all the three treatments. The presence of litter decreased CH4 uptake during wet season (P < 0.05), but not during dry season. There was a similar increase in seedlings-mediated N2O emissions during wet and dry seasons, indicating that seedlings increased N2O emission in both seasons. A strong positive relationship existed between CH4 fluxes and soil moisture for all the three treatments, and weak relationship between CH4 fluxes and soil temperature for treatment B and treatment C. The N2O fluxes correlated with soil temperature for all the three treatments.

  19. Ant-lepidopteran associations along African forest edges

    Science.gov (United States)

    Dejean, Alain; Azémar, Frédéric; Libert, Michel; Compin, Arthur; Hérault, Bruno; Orivel, Jérôme; Bouyer, Thierry; Corbara, Bruno

    2017-02-01

    Working along forest edges, we aimed to determine how some caterpillars can co-exist with territorially dominant arboreal ants (TDAAs) in tropical Africa. We recorded caterpillars from 22 lepidopteran species living in the presence of five TDAA species. Among the defoliator and/or nectarivorous caterpillars that live on tree foliage, the Pyralidae and Nymphalidae use their silk to protect themselves from ant attacks. The Notodontidae and lycaenid Polyommatinae and Theclinae live in direct contact with ants; the Theclinae even reward ants with abundant secretions from their Newcomer gland. Lichen feeders (lycaenid; Poritiinae), protected by long bristles, also live among ants. Some lycaenid Miletinae caterpillars feed on ant-attended membracids, including in the shelters where the ants attend them; Lachnocnema caterpillars use their forelegs to obtain trophallaxis from their host ants. Caterpillars from other species live inside weaver ant nests. Those of the genus Euliphyra (Miletinae) feed on ant prey and brood and can obtain trophallaxis, while those from an Eberidae species only prey on host ant eggs. Eublemma albifascia (Erebidae) caterpillars use their thoracic legs to obtain trophallaxis and trophic eggs from ants. Through transfer bioassays of last instars, we noted that herbivorous caterpillars living in contact with ants were always accepted by alien conspecific ants; this is likely due to an intrinsic appeasing odor. Yet, caterpillars living in ant shelters or ant nests probably acquire cues from their host colonies because they were considered aliens and killed. We conclude that co-evolution with ants occurred similarly in the Heterocera and Rhopalocera.

  20. Contrasting taxonomic and phylogenetic diversity responses to forest modifications: comparisons of taxa and successive plant life stages in South African scarp forest.

    Science.gov (United States)

    Grass, Ingo; Brandl, Roland; Botzat, Alexandra; Neuschulz, Eike Lena; Farwig, Nina

    2015-01-01

    The degradation of natural forests to modified forests threatens subtropical and tropical biodiversity worldwide. Yet, species responses to forest modification vary considerably. Furthermore, effects of forest modification can differ, whether with respect to diversity components (taxonomic or phylogenetic) or to local (α-diversity) and regional (β-diversity) spatial scales. This real-world complexity has so far hampered our understanding of subtropical and tropical biodiversity patterns in human-modified forest landscapes. In a subtropical South African forest landscape, we studied the responses of three successive plant life stages (adult trees, saplings, seedlings) and of birds to five different types of forest modification distinguished by the degree of within-forest disturbance and forest loss. Responses of the two taxa differed markedly. Thus, the taxonomic α-diversity of birds was negatively correlated with the diversity of all plant life stages and, contrary to plant diversity, increased with forest disturbance. Conversely, forest disturbance reduced the phylogenetic α-diversity of all plant life stages but not that of birds. Forest loss neither affected taxonomic nor phylogenetic diversity of any taxon. On the regional scale, taxonomic but not phylogenetic β-diversity of both taxa was well predicted by variation in forest disturbance and forest loss. In contrast to adult trees, the phylogenetic diversity of saplings and seedlings showed signs of contemporary environmental filtering. In conclusion, forest modification in this subtropical landscape strongly shaped both local and regional biodiversity but with contrasting outcomes. Phylogenetic diversity of plants may be more threatened than that of mobile species such as birds. The reduced phylogenetic diversity of saplings and seedlings suggests losses in biodiversity that are not visible in adult trees, potentially indicating time-lags and contemporary shifts in forest regeneration. The different

  1. Contrasting taxonomic and phylogenetic diversity responses to forest modifications: comparisons of taxa and successive plant life stages in South African scarp forest.

    Directory of Open Access Journals (Sweden)

    Ingo Grass

    Full Text Available The degradation of natural forests to modified forests threatens subtropical and tropical biodiversity worldwide. Yet, species responses to forest modification vary considerably. Furthermore, effects of forest modification can differ, whether with respect to diversity components (taxonomic or phylogenetic or to local (α-diversity and regional (β-diversity spatial scales. This real-world complexity has so far hampered our understanding of subtropical and tropical biodiversity patterns in human-modified forest landscapes. In a subtropical South African forest landscape, we studied the responses of three successive plant life stages (adult trees, saplings, seedlings and of birds to five different types of forest modification distinguished by the degree of within-forest disturbance and forest loss. Responses of the two taxa differed markedly. Thus, the taxonomic α-diversity of birds was negatively correlated with the diversity of all plant life stages and, contrary to plant diversity, increased with forest disturbance. Conversely, forest disturbance reduced the phylogenetic α-diversity of all plant life stages but not that of birds. Forest loss neither affected taxonomic nor phylogenetic diversity of any taxon. On the regional scale, taxonomic but not phylogenetic β-diversity of both taxa was well predicted by variation in forest disturbance and forest loss. In contrast to adult trees, the phylogenetic diversity of saplings and seedlings showed signs of contemporary environmental filtering. In conclusion, forest modification in this subtropical landscape strongly shaped both local and regional biodiversity but with contrasting outcomes. Phylogenetic diversity of plants may be more threatened than that of mobile species such as birds. The reduced phylogenetic diversity of saplings and seedlings suggests losses in biodiversity that are not visible in adult trees, potentially indicating time-lags and contemporary shifts in forest regeneration. The

  2. Spatial distribution by Canistropsis microps (E. Morren ex Mez Leme (Bromeliaceae: Bromelioideae in the Atlantic rain forest in Ilha Grande, Southeastern Brazil

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    AF. Nunes-Freitas

    Full Text Available Canistropsis microps (Bromeliaceae: Bromelioideae is an endemic species of Atlantic rain forest areas in Rio de Janeiro State, which are very abundant in not very disturbed forests in Ilha Grande, on the southern coast of the State. In this study, we analyzed the vertical and horizontal distribution patterns of the species in an area of rain forest with little evidence of disturbance at Vila Dois Rios, Ilha Grande, relating the patterns to sunlight in the microhabitat. We also identified the types of substrate used by the species and the rate of asexual reproduction. Canistropsis microps had high densities (estimated at 84,425 rosettes/ha, and has an aggregated distribution (Id = 2.86. About 80% of the rosettes were generated by clonal growth, whereas less than 20% were produced from seedlings. Most of the rosettes were found on straight tree trunks (DBH > 50 cm. There was a significant inverse correlation between the incidence of sunlight in the habitat and the abundance of individuals. Rosettes were found up to a maximum height of 9.5 m, but most occured between 1.5 and 5.5 m, where light varied from 25 to 50 µmol.s-1.m-2. We conclude that vertical and horizontal distribution patterns in C. microps may be partially explained by the occurrence of appropriate substrate, an intensity of sunlight favorable to the development of the species and to a high rate of vegetative reproduction.

  3. One-year delayed effect of fog on malaria transmission: a time-series analysis in the rain forest area of Mengla County, south-west China

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    Goggins William B

    2008-06-01

    Full Text Available Abstract Background Malaria is a major public health burden in the tropics with the potential to significantly increase in response to climate change. Analyses of data from the recent past can elucidate how short-term variations in weather factors affect malaria transmission. This study explored the impact of climate variability on the transmission of malaria in the tropical rain forest area of Mengla County, south-west China. Methods Ecological time-series analysis was performed on data collected between 1971 and 1999. Auto-regressive integrated moving average (ARIMA models were used to evaluate the relationship between weather factors and malaria incidence. Results At the time scale of months, the predictors for malaria incidence included: minimum temperature, maximum temperature, and fog day frequency. The effect of minimum temperature on malaria incidence was greater in the cool months than in the hot months. The fog day frequency in October had a positive effect on malaria incidence in May of the following year. At the time scale of years, the annual fog day frequency was the only weather predictor of the annual incidence of malaria. Conclusion Fog day frequency was for the first time found to be a predictor of malaria incidence in a rain forest area. The one-year delayed effect of fog on malaria transmission may involve providing water input and maintaining aquatic breeding sites for mosquitoes in vulnerable times when there is little rainfall in the 6-month dry seasons. These findings should be considered in the prediction of future patterns of malaria for similar tropical rain forest areas worldwide.

  4. Origin and global diversification patterns of tropical rain forests: inferences from a complete genus-level phylogeny of palms

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    Couvreur Thomas LP

    2011-06-01

    Full Text Available Abstract Background Understanding how biodiversity is shaped through time is a fundamental question in biology. Even though tropical rain forests (TRF represent the most diverse terrestrial biomes on the planet, the timing, location and mechanisms of their diversification remain poorly understood. Molecular phylogenies are valuable tools for exploring these issues, but to date most studies have focused only on recent time scales, which minimises their explanatory potential. In order to provide a long-term view of TRF diversification, we constructed the first complete genus-level dated phylogeny of a largely TRF-restricted plant family with a known history dating back to the Cretaceous. Palms (Arecaceae/Palmae are one of the most characteristic and ecologically important components of TRF worldwide, and represent a model group for the investigation of TRF evolution. Results We provide evidence that diversification of extant lineages of palms started during the mid-Cretaceous period about 100 million years ago. Ancestral biome and area reconstructions for the whole family strongly support the hypothesis that palms diversified in a TRF-like environment at northern latitudes. Finally, our results suggest that palms conform to a constant diversification model (the 'museum' model or Yule process, at least until the Neogene, with no evidence for any change in diversification rates even through the Cretaceous/Paleogene mass extinction event. Conclusions Because palms are restricted to TRF and assuming biome conservatism over time, our results suggest the presence of a TRF-like biome in the mid-Cretaceous period of Laurasia, consistent with controversial fossil evidence of the earliest TRF. Throughout its history, the TRF biome is thought to have been highly dynamic and to have fluctuated greatly in extent, but it has persisted even during climatically unfavourable periods. This may have allowed old lineages to survive and contribute to the steady

  5. The emergence of modern type rain forests and mangroves and their traces in the palaeobotanical record during the Late Cretaceous and early Tertiary

    Science.gov (United States)

    Mohr, Barbara; Coiffard, Clément

    2014-05-01

    The origin of modern rain forests is still very poorly known. This ecosystem could have potentially fully evolved only after the development of relatively high numbers of flowering plant families adapted to rain forest conditions. During the early phase of angiosperm evolution in the early Cretaceous the palaeo-equatorial region was located in a seasonally dry climatic belt, so that during this phase, flowering plants often show adaptations to drought, rather than to continuously wet climate conditions. Therefore it is not surprising that except for the Nymphaeales, the most basal members of extant angiosperm families have members that do not necessarily occur in the continuously wet tropics today. However, during the late Early Cretaceous several clades emerged that later would give rise to families that are typically found today mostly in (shady) moist places in warmer regions. This is especially seen among the monocotyledons, a group of the mesangiosperms, that developed in many cases large leaves often with very specific venation patterns that make these leaves very unique and well recognizable. Especially members of three groups are here of interest: the arum family (Araceae), the palms (Arecaceae) and the Ginger and allies (Zingiberales). The earliest fossil of Araceae are restricted to low latitudes during the lower Cretaceous. Arecaceae and Zingiberales do not appear in the fossil record before the early late Cretaceous and occur at mid latitudes. During the Late Cretaceous, Araceae are represented at mid latitudes by non-tropical early diverging members and at low latitudes by derived rainforest members. Palms became widespread during the Late Cretataceous and also Nypa, a typical element of tropical to subtropical mangrove environments evolved during this time period. During the Paleocene Arecaceae appear to be restricted to lower latitudes as well as Zingiberales. All three groups are again widespread during the Eocene, reaching higher latitudes and

  6. The community resource management area mechanism: a strategy to manage African forest resources for REDD+.

    Science.gov (United States)

    Asare, Rebecca A; Kyei, Andrew; Mason, John J

    2013-01-01

    Climate change poses a significant threat to Africa, and deforestation rates have increased in recent years. Mitigation initiatives such as REDD+ are widely considered as potentially efficient ways to generate emission reductions (or removals), conserve or sustainably manage forests, and bring benefits to communities, but effective implementation models are lacking. This paper presents the case of Ghana's Community Resource Management Area (CREMA) mechanism, an innovative natural resource governance and landscape-level planning tool that authorizes communities to manage their natural resources for economic and livelihood benefits. This paper argues that while the CREMA was originally developed to facilitate community-based wildlife management and habitat protection, it offers a promising community-based structure and process for managing African forest resources for REDD+. At a theoretical level, it conforms to the ecological, socio-cultural and economic factors that drive resource-users' decision process and practices. And from a practical mitigation standpoint, the CREMA has the potential to help solve many of the key challenges for REDD+ in Africa, including definition of boundaries, smallholder aggregation, free prior and informed consent, ensuring permanence, preventing leakage, clarifying land tenure and carbon rights, as well as enabling equitable benefit-sharing arrangements. Ultimately, CREMA's potential as a forest management and climate change mitigation strategy that generates livelihood benefits for smallholder farmers and forest users will depend upon the willingness of African governments to support the mechanism and give it full legislative backing, and the motivation of communities to adopt the CREMA and integrate democratic decision-making and planning with their traditional values and natural resource management systems.

  7. Acid Rain

    Science.gov (United States)

    Bricker, Owen P.; Rice, Karen C.; Dietrich, W.E.; Sposito, Garrison

    1997-01-01

    Acid deposition, or acid rain as it is more commonly referred to, has become a widely publicized environmental issue in the U.S. over the past decade. The term usually conjures up images of fish kills, dying forests, "dead" lakes, and damage to monuments and other historic artifacts. The primary cause of acid deposition is emission of S02 and NOx to the atmosphere during the combustion of fossil fuels. Oxidation of these compounds in the atmosphere forms strong acids - H2SO4 and HNO3 - which are returned to the Earth in rain, snow, fog, cloud water, and as dry deposition.Although acid deposition has only recently been recognized as an environmental problem in the U.S., it is not a new phenomenon (Cogbill & Likens 1974). As early as the middle of the 17th century in England, the deleterious effects of industrial emissions on plants, animals, and humans, and the atmospheric transport of pollutants between England and France had become issues of concern (Evelyn 1661, Graunt 1662). It is interesting that well over three hundred years ago in England, recommendations were made to move industry outside of towns and build higher chimneys to spread the pollution into "distant parts." Increasing the height of smokestacks has helped alleviate local problems, but has exacerbated others. In the U.S. the height of the tallest smokestack has more than doubled, and the average height of smokestacks has tripled since the 1950s (Patrick et al 1981). This trend occurred in most industrialized nations during the 20th century and has had the effect of transforming acid rain from a local urban problem into a problem of global scale.

  8. Towards ground-truthing of spaceborne estimates of above-ground life biomass and leaf area index in tropical rain forests

    Directory of Open Access Journals (Sweden)

    P. Köhler

    2010-08-01

    Full Text Available The canopy height h of forests is a key variable which can be obtained using air- or spaceborne remote sensing techniques such as radar interferometry or LIDAR. If new allometric relationships between canopy height and the biomass stored in the vegetation can be established this would offer the possibility for a global monitoring of the above-ground carbon content on land. In the absence of adequate field data we use simulation results of a tropical rain forest growth model to propose what degree of information might be generated from canopy height and thus to enable ground-truthing of potential future satellite observations. We here analyse the correlation between canopy height in a tropical rain forest with other structural characteristics, such as above-ground life biomass (AGB (and thus carbon content of vegetation and leaf area index (LAI and identify how correlation and uncertainty vary for two different spatial scales. The process-based forest growth model FORMIND2.0 was applied to simulate (a undisturbed forest growth and (b a wide range of possible disturbance regimes typically for local tree logging conditions for a tropical rain forest site on Borneo (Sabah, Malaysia in South-East Asia. In both undisturbed and disturbed forests AGB can be expressed as a power-law function of canopy height h (AGB = a · hb with an r2 ~ 60% if data are analysed in a spatial resolution of 20 m × 20 m (0.04 ha, also called plot size. The correlation coefficient of the regression is becoming significant better in the disturbed forest sites (r2 = 91% if data are analysed hectare wide. There seems to exist no functional dependency between LAI and canopy height, but there is also a linear correlation (r2 ~ 60% between AGB and the area fraction of gaps in which the canopy is highly disturbed. A reasonable agreement of our results with observations is obtained from a

  9. Towards ground-truthing of spaceborne estimates of above-ground life biomass and leaf area index in tropical rain forests

    Science.gov (United States)

    Köhler, P.; Huth, A.

    2010-08-01

    The canopy height h of forests is a key variable which can be obtained using air- or spaceborne remote sensing techniques such as radar interferometry or LIDAR. If new allometric relationships between canopy height and the biomass stored in the vegetation can be established this would offer the possibility for a global monitoring of the above-ground carbon content on land. In the absence of adequate field data we use simulation results of a tropical rain forest growth model to propose what degree of information might be generated from canopy height and thus to enable ground-truthing of potential future satellite observations. We here analyse the correlation between canopy height in a tropical rain forest with other structural characteristics, such as above-ground life biomass (AGB) (and thus carbon content of vegetation) and leaf area index (LAI) and identify how correlation and uncertainty vary for two different spatial scales. The process-based forest growth model FORMIND2.0 was applied to simulate (a) undisturbed forest growth and (b) a wide range of possible disturbance regimes typically for local tree logging conditions for a tropical rain forest site on Borneo (Sabah, Malaysia) in South-East Asia. In both undisturbed and disturbed forests AGB can be expressed as a power-law function of canopy height h (AGB = a · hb) with an r2 ~ 60% if data are analysed in a spatial resolution of 20 m × 20 m (0.04 ha, also called plot size). The correlation coefficient of the regression is becoming significant better in the disturbed forest sites (r2 = 91%) if data are analysed hectare wide. There seems to exist no functional dependency between LAI and canopy height, but there is also a linear correlation (r2 ~ 60%) between AGB and the area fraction of gaps in which the canopy is highly disturbed. A reasonable agreement of our results with observations is obtained from a comparison of the simulations with permanent sampling plot (PSP) data from the same region and with the

  10. Desertification and a shift of forest species in the West African Sahel

    Science.gov (United States)

    Gonzalez, P.

    2001-01-01

    Original field data show that forest species richness and tree density in the West African Sahel declined in the last half of the 20th century. Average forest species richness of areas of 4 km2 in Northwest Senegal fell from 64 ?? 2 species ca 1945 to 43 ?? 2 species in 1993, a decrease significant at p changes have shifted vegetation zones toward areas of higher rainfall at an average rate of 500 to 600 m yr-1. Arid Sahel species have expanded in the north, tracking a concomitant retraction of mesic Sudan and Guinean species to the south. Multivariate analyses identify latitude and longitude, proxies for rainfall and temperature, as the most significant factors explaining tree and shrub distribution. The changes also decreased human carrying capacity to below actual population densities. The rural population of 45 people km-2 exceeded the 1993 carrying capacity, for firewood from shrubs, of 13 people km-2 (range 1 to 21 people km-2). As an adaptation strategy, ecological and socioeconomic factors favor the natural regeneration of local species over the massive plantation of exotic species. Natural regeneration is a traditional practice in which farmers select small field trees that they wish to raise to maturity, protect them, and prune them to promote rapid growth of the apical meristem. The results of this research provide evidence for desertification in the West African Sahel. These documented impacts of desertification foreshadow possible future effects of climate change.

  11. Seed rain, soil seed bank, seed loss and regeneration of Castanopsis fargesii (Fagaceae) in a subtropical evergreen broad-leaved forest

    Science.gov (United States)

    Du, X.; Guo, Q.; Gao, X.; Ma, K.

    2007-01-01

    Understanding the seed rain and seed loss dynamics in the natural condition has important significance for revealing the natural regeneration mechanisms. We conducted a 3-year field observation on seed rain, seed loss and natural regeneration of Castanopsis fargesii Franch., a dominant tree species in evergreen broad-leaved forests in Dujiangyan, southwestern China. The results showed that: (1) there were marked differences in (mature) seed production between mast (733,700 seeds in 2001) and regular (51,200 and 195,600 seeds in 2002 and 2003, respectively) years for C. fargesii. (2) Most seeds were dispersed in leaf litter, humus and 0-2 cm depth soil in seed bank. (3) Frequency distributions of both DBH and height indicated that C. fargesii had a relatively stable population. (4) Seed rain, seed ground density, seed loss, and leaf fall were highly dynamic and certain quantity of seeds were preserved on the ground for a prolonged time due to predator satiation in both the mast and regular years so that the continuous presence of seed bank and seedling recruitments in situ became possible. Both longer time observations and manipulative experiments should be carried out to better understand the roles of seed dispersal and regeneration process in the ecosystem performance. ?? 2006 Elsevier B.V. All rights reserved.

  12. Fine-Scale Genetic Structure and Cryptic Associations Reveal Evidence of Kin-Based Sociality in the African Forest Elephant

    OpenAIRE

    Stephanie G Schuttler; Jessica A Philbrick; Jeffery, Kathryn J.; Eggert, Lori S.

    2014-01-01

    Spatial patterns of relatedness within animal populations are important in the evolution of mating and social systems, and have the potential to reveal information on species that are difficult to observe in the wild. This study examines the fine-scale genetic structure and connectivity of groups within African forest elephants, Loxodonta cyclotis, which are often difficult to observe due to forest habitat. We tested the hypothesis that genetic similarity will decline with increasing geograph...

  13. Above ground biomass estimation from lidar and hyperspectral airbone data in West African moist forests.

    Science.gov (United States)

    Vaglio Laurin, Gaia; Chen, Qi; Lindsell, Jeremy; Coomes, David; Cazzolla-Gatti, Roberto; Grieco, Elisa; Valentini, Riccardo

    2013-04-01

    The development of sound methods for the estimation of forest parameters such as Above Ground Biomass (AGB) and the need of data for different world regions and ecosystems, are widely recognized issues due to their relevance for both carbon cycle modeling and conservation and policy initiatives, such as the UN REDD+ program (Gibbs et al., 2007). The moist forests of the Upper Guinean Belt are poorly studied ecosystems (Vaglio Laurin et al. 2013) but their role is important due to the drier condition expected along the West African coasts according to future climate change scenarios (Gonzales, 2001). Remote sensing has proven to be an effective tool for AGB retrieval when coupled with field data. Lidar, with its ability to penetrate the canopy provides 3D information and best results. Nevertheless very limited research has been conducted in Africa tropical forests with lidar and none to our knowledge in West Africa. Hyperspectral sensors also offer promising data, being able to evidence very fine radiometric differences in vegetation reflectance. Their usefulness in estimating forest parameters is still under evaluation with contrasting findings (Andersen et al. 2008, Latifi et al. 2012), and additional studies are especially relevant in view of forthcoming satellite hyperspectral missions. In the framework of the EU ERC Africa GHG grant #247349, an airborne campaign collecting lidar and hyperspectral data has been conducted in March 2012 over forests reserves in Sierra Leone and Ghana, characterized by different logging histories and rainfall patterns, and including Gola Rainforest National Park, Ankasa National Park, Bia and Boin Forest Reserves. An Optech Gemini sensor collected the lidar dataset, while an AISA Eagle sensor collected hyperspectral data over 244 VIS-NIR bands. The lidar dataset, with a point density >10 ppm was processed using the TIFFS software (Toolbox for LiDAR Data Filtering and Forest Studies)(Chen 2007). The hyperspectral dataset, geo

  14. The Junkyard in the Jungle: Transnational, Transnatural Nature in Karen Tei Yamashita’s Through the Arc of the Rain Forest

    Directory of Open Access Journals (Sweden)

    Begoña Simal

    2010-03-01

    Full Text Available In this new millennium the relatively young field of ecocriticism has had to face important transdisciplinary, transnational, and transnatural challenges. This article attempts to demonstrate how two of the major changes that environmental criticism is currently undergoing, the transnational turn and the transnatural challenge, have both been encoded in Through the Arc of the Rain Forest (1990, the first novel published by Karen Tei Yamashita. I particularly focus on a significant episode in Through the Arc of the Rain Forest, when a peculiar anthropogenic ecosystem is discovered, and interpret it according to Leo Marx’s classic paradigm of “the machine in the garden.” I intend to prove that Yamashita’s novel not only revisits the old master theory but also revamps it by destabilizing the classic human-nature divide inherent in first-wave ecocriticism and by adding the transnational ingredient. Thus, the machine-in-the-garden paradigm is updated in order to incorporate the broadening of current environmental criticism, both literally (globalization and conceptually (transnatural nature. While at times Marx’s paradigm may metamorphose in intriguing ways, the old trope also corroborates its continuing validity. Though filtered by the sieve of globalization and shaken by the emergence of cyborg ecosystems, “the machine in the garden” has survived as a compelling ecocritical framework, even if it occasionally mutates into a junkyard in the jungle.

  15. Effects of land-use changes on evapotranspiration of tropical rain forest margin area in Central Sulawesi (Indonesia): Modelling study with a regional SVAT model

    DEFF Research Database (Denmark)

    Olchev, A.; Ibrom, Andreas; Priess, J.

    2008-01-01

    The impact of deforestation and land-use changes on evapotranspiration of mountainous tropical rain forest area in the northern part of the Lore-Lindu National Park (LLNP) in Central Sulawesi (Indonesia) was quantified using a regional process-based SVAT model "SVAT-Regio". Description of evapotr......The impact of deforestation and land-use changes on evapotranspiration of mountainous tropical rain forest area in the northern part of the Lore-Lindu National Park (LLNP) in Central Sulawesi (Indonesia) was quantified using a regional process-based SVAT model "SVAT-Regio". Description...... of evapotranspiration of a non-uniform land surface in local and regional scales in SVAT-Regio is based on equations of energy and water balances of individual plants, plant canopy and soil layers for each of many grid cells into which the entire study area is divided. The model uses a multi-layered representation...... of vegetation cover and soil structure that allows to describe the partitioning of energy and H2O-fluxes among different canopy layers and soil, and to quantify more precisely the total ecosystem fluxes. Selective integration of grid cell fluxes on space and time allows estimating the energy and water fluxes...

  16. Simulation of water available for runoff in clearcut forest openings during rain-on-snow events in the western Cascade Range of Oregon and Washington

    Science.gov (United States)

    van Heeswijk, Marijke; Kimball, J.S.; Marks, Danny

    1996-01-01

    Rain-on-snow events are common on mountain slopes within the transient-snow zone of the Pacific Northwest. These events make more water available for runoff than does precipitation alone by melting the snowpack and by adding a small amount of condensate to the snowpack. In forest openings (such as those resulting from clearcut logging), the amount of snow that accumulates and the turbulent- energy input to the snowpack are greater than below forest stands. Both factors are believed to contribute to a greater amount of water available for runoff during rain-on-snow events in forest openings than forest stands. Because increased water available for runoff may lead to increased downstream flooding and erosion, knowledge of the amount of snowmelt that can occur during rain on snow and the processes that control snowmelt in forest openings is useful when making land-use decisions. Snow accumulation and melt were simulated for clearcut conditions only, using an enery- balance approach that accounts for the most important energy and mass exchanges between a snowpack and its environment. Meteorological measurements provided the input for the simulations. Snow accumulation and melt were not simulated in forest stands because interception of precipitation processes are too complex to simulate with a numerical model without making simplifying assumptions. Such a model, however, would need to be extensively tested against representative observations, which were not available for this study. Snowmelt simulated during three rain-on-snow events (measured in a previous study in a clearcut in the transient-snow zone of the H.J. Andrews Experimental Forest in Oregon) demonstrated that melt generation is most sensitive to turbulent- energy exchanges between the air and the snowpack surface. As a result, the most important climate variable that controls snowmelt is wind speed. Air temperature, however, is a significant variable also. The wind speeds were light, with a maximum of 3

  17. Tropical monsoon forest in Yunnan with comparison to the tropical rain forest%云南热带季雨林及其与热带雨林植被的比较

    Institute of Scientific and Technical Information of China (English)

    朱华

    2011-01-01

    In Chinese botanical literature, the term "tropical monsoon forest" is explained and used inconsistently and is often confused with tropical rain forest. My objective is to clarify differences between the two forests. Schimper defined tropical monsoon forest as being more or less leafless during the dry season and considered it a transitional vegetation type between tropical rain forest and savanna in terms of physiognomy and distribution. I compared tropical monsoon forest and rain forest in physiognomy, floristic composition and geographical elements to describe and characterize the monsoon forest in Yunnan, China. The tropical monsoon forest in Yunnan occurs mainly on river banks and in basins of several large rivers below 1 000 m altitude. The forest has one or two tree layers, and trees of at least the top layer are deciduous in the dry season. In life forms, the forest is rich in hemicryptophytes and relatively rich in geophytes and therophytes, but less rich in woody lianas and almost lacks megaphanerophytes and chamaephytes compared to tropical rain forest. In leaf size and form, the forest has more microphyllous leaves and compound leaves (24% and 44% of tree species, respectively) than tropical rain forest.In terms of floristic elements, the forest has a greater percentage of species of pantropic distribution (30% of the genera) and tropical Asia and tropical Africa disjunct distribution than tropical rain forest. Thus, the tropical monsoon forest in Yunnan has more diverse geographical elements in its flora and a complicated evolution history.%在中国植物学文献中,对热带季雨林的解释和运用是不一致的,特别是易于把季雨林与热带雨林相混淆.季雨林是在具有明显干、湿季变化的热带季风气候下发育的一种热带落叶森林植被,是介于热带雨林与热带稀树草原(savanna)之间的一个植被类型.云南的热带季雨林在分布生境、生态外貌特征、植物种类组成和地理

  18. Climate, herbivory, and fire controls on tropical African forest for the last 60ka

    Science.gov (United States)

    Ivory, Sarah J.; Russell, James

    2016-09-01

    The Last Glacial Maximum (LGM) in Africa was drier than today and was followed by rapid step-wise climate changes during the last deglacial period. In much of Africa, these changes led to a drastic reduction of lowland forest area during the LGM, followed by recolonization of the lowlands by forest and woodland in concert with regional warming and wetting. However, the history of southeastern African vegetation contrasts with that observed further north. In particular, forest expansion appears to have occurred in southeastern Africa during episodes of high-latitude northern hemisphere cooling. Although vegetation history in Africa is generally assumed to relate purely to climate, previous studies have not addressed potential feedbacks between climate, vegetation, and disturbance regimes (fire, herbivory) that may create tipping points in ecosystems. This climate-vegetation history has profound implications for our understanding of the modern architecture of lowland and highland forests, both thought to be at risk from future climate change. Here we present analyses of fossil pollen, charcoal, and Sporormiella (dung fungus) on a continuous 60 kyr record from central Lake Tanganyika, Southeast Africa, that illustrates the interplay of climate and disturbance regimes in shaping vegetation composition and structure. We observe that extensive forests dominated the region during the last glacial period despite evidence of decreased rainfall. At the end of the LGM, forest opening at ∼17.5 ka followed warming temperatures but preceded rising precipitation, suggesting that temperature-induced water stress and disturbance from fire and herbivory affected initial landscape transformation. Our Sporormiella record indicates that mega-herbivore populations increased at the early Holocene. This higher animal density increased plant species richness and encouraged landscape heterogeneity until the mid-Holocene. At this time, regional drying followed by the onset of the Iron Age

  19. Atmospheric salt deposition in a tropical mountain rain forest at the eastern Andean slopes of South Ecuador – Pacific or Atlantic origin?

    Directory of Open Access Journals (Sweden)

    S. Makowski Giannoni

    2015-10-01

    its importance for herbivory, litter decomposition and thus, carbon cycling. Salt deposition should generally decline with distance from its marine sources. For tropical South America, a negative east-west salt availability gradient is assumed in the Amazon as a consequence of the barrier effect of the Andes for Pacific air masses. However, this generalized pattern may not hold for the tropical mountain rain forest in the Andes of southern Ecuador. To analyze salt availability, we investigate the deposition of Na+ and Cl- which are good proxies of sea spray aerosol. Because of the complexity of the terrain and related cloud and rain formation processes, salt deposition was analyzed from both, rain and occult precipitation (OP water along an altitudinal gradient over a period from 2004 to 2009. To assess the influence of Atlantic and Pacific air masses on the locally observed deposition of sodium and chloride, sea-salt aerosol concentration data from the Monitoring Atmospheric Composition and Climate (MACC reanalysis dataset and back-trajectory statistical methods were combined. Our results based on deposition time series and 2192 generated trajectories show a clear difference in the temporal variation of sodium and chloride concentration due to height and exposure to winds. The sea-salt transport was highly seasonal where higher locations revealed a stronger seasonality. Although the influence of the easterlies were predominant regarding atmospheric circulation, the statistical analysis of trajectories and hybrid receptor models revealed a stronger impact of the Pacific sea-salt sources on the deposition at the study area. The highest concentration in rain and cloud water was found between September and February originating from both, the equatorial Pacific and Atlantic. However, the Pacific sources contributed with up to 25 % to the observed total concentration of Na+ and Cl- at the receptor site although the frequency of occurrence of the respective trajectories

  20. Long-term responses of populations and communities of trees to selective logging in tropical rain forests in Guyana

    NARCIS (Netherlands)

    Arets, E.J.M.M. (Eric Jacobus Monica Maria)

    2005-01-01

    Since only a small area of Guyana's forest can be effectively protected and because timber harvesting is an important source of income, logged forests will play an important role in the conservation of biodiversity in Guyana. Selective logging, in which only a few trees per hectare are harvested and

  1. Western equatorial African forest-savanna mosaics: a legacy of late Holocene climatic change?

    Directory of Open Access Journals (Sweden)

    A. Ngomanda

    2009-10-01

    Full Text Available Past vegetation and climate changes reconstructed using two pollen records from Lakes Maridor and Nguène, located in the coastal savannas and inland rainforest of Gabon, respectively, provide new insights into the environmental history of western equatorial African rainforests during the last 4500 cal yr BP. These pollen records indicate that the coastal savannas of western equatorial Africa did not exist during the mid-Holocene and instead the region was covered by evergreen rainforests. From ca. 4000 cal yr BP a progressive decline of inland evergreen rainforest, accompanied by the expansion of semi-deciduous rainforest, occurred synchronously with grassland colonisation in the coastal region of Gabon. The contraction of moist evergreen rainforest and the establishment of coastal savannas in Gabon suggest decreasing humidity from ca. 4000 cal yr BP. The marked reduction in evergreen rainforest and subsequent savanna expansion was followed from 2700 cal yr BP by the colonization of secondary forests dominated by the palm, Elaeis guineensis, and the shrub, Alchornea cordifolia (Euphorbiaceae. A return to wetter climatic conditions from about 1400 cal yr BP led to the renewed spread of evergreen rainforest inland, whereas a forest-savanna mosaic still persists in the coastal region. There is no evidence to suggest that the major environmental changes observed were driven by human impact.

  2. Western equatorial African forest-savanna mosaics: a legacy of late Holocene climatic change?

    Science.gov (United States)

    Ngomanda, A.; Chepstow-Lusty, A.; Makaya, M.; Favier, C.; Schevin, P.; Maley, J.; Fontugne, M.; Oslisly, R.; Jolly, D.

    2009-10-01

    Past vegetation and climate changes reconstructed using two pollen records from Lakes Maridor and Nguène, located in the coastal savannas and inland rainforest of Gabon, respectively, provide new insights into the environmental history of western equatorial African rainforests during the last 4500 cal yr BP. These pollen records indicate that the coastal savannas of western equatorial Africa did not exist during the mid-Holocene and instead the region was covered by evergreen rainforests. From ca. 4000 cal yr BP a progressive decline of inland evergreen rainforest, accompanied by the expansion of semi-deciduous rainforest, occurred synchronously with grassland colonisation in the coastal region of Gabon. The contraction of moist evergreen rainforest and the establishment of coastal savannas in Gabon suggest decreasing humidity from ca. 4000 cal yr BP. The marked reduction in evergreen rainforest and subsequent savanna expansion was followed from 2700 cal yr BP by the colonization of secondary forests dominated by the palm, Elaeis guineensis, and the shrub, Alchornea cordifolia (Euphorbiaceae). A return to wetter climatic conditions from about 1400 cal yr BP led to the renewed spread of evergreen rainforest inland, whereas a forest-savanna mosaic still persists in the coastal region. There is no evidence to suggest that the major environmental changes observed were driven by human impact.

  3. New records of Aphyllophorales (Basidiomycota in the Atlantic Rain Forest in Northeast Brazil Novos registros de Aphyllophorales (Basidiomycota em Mata Atlântica no Nordeste brasileiro

    Directory of Open Access Journals (Sweden)

    Tatiana Baptista Gibertoni

    2004-12-01

    Full Text Available Non-poroid Aphyllophorales (Basidiomycota in areas of the Atlantic Rain Forest in Northeast Brazil are reported. Auriscalpium villipes (Lloyd Snell & E.A. Dick, Climacodon pulcherrimus (Berk. & M.A. Curtis Nikol., Gloeodontia discolor (Berk. & M.A. Curtis Boidin, Irpex lacteus (Fr.: Fr. Fr. and Scytinostroma duriusculum (Berk. & Broome Donk are new records to Northeast Brazil.Aphyllophorales (Basidiomycota não poróides foram registrados em áreas de Mata Atlântica do Nordeste brasileiro. Auriscalpium villipes (Lloyd Snell & E.A. Dick, Climacodon pulcherrimus (Berk. & M.A. Curtis Nikol., Gloeodontia discolor (Berk. & M.A. Curtis Boidin, Irpex lacteus (Fr.: Fr. Fr. e Scytinostroma duriusculum (Berk. & Broome Donk são novas ocorrências para o Nordeste do Brasil.

  4. Advancements and prospects in forest seed rain studies%森林种子雨研究进展与展望

    Institute of Scientific and Technical Information of China (English)

    杜彦君; 马克平

    2012-01-01

    种子雨阶段是植物更新的关键环节,它连接着繁殖生产与植物后续生活史阶段,对群落结构有着重要的影响.虽然早在19世纪中叶达尔文就认识到种子扩散的重要性,然而对种子雨的广泛研究于20世纪80年代初才开始.本文聚焦于森林木本植物种子雨研究,首先介绍了种子雨监测方法,包括收集器的布置,种子雨的收集、分离和鉴定.然后综述了种子雨的4个主要研究方向:种子产量的时间和空间变化格局(包括季节变化、年际变化和空间变化)、增补限制及其在物种多样性维持中的作用、验证负密度效应假说、种子雨与其他生活史阶段(土壤种子库、幼苗、幼树及母树)的比较.未来还需要加强对种子雨的长期监测,开展增补限制的跨纬度比较研究,探讨植物早期更新阶段负密度效应沿纬度梯度的变化规律,加强数学模型以及分子标记和稳定同位素技术等新手段的运用.%Seed dispersal links the reproductive cycle of adult plants with the establishment of their offspring and is widely recognized as a process that has a profound effect on the structure of tree communities. Although ecologists as early as Darwin realized the importance of seed dispersal, the scientific study of seed rain did not gain momentum until the early 1980s. A considerable amount of seed rain research has been conducted since then. Here we focused on seed rain studies of woody plants in forests. Seed rain monitoring methods are introduced, including seedtrap set, seed collection, separation, and identification. We also review recent progress in these studies-temporal and spatial variation in seed rain (seasonal, intra-annual, and spatial variations), recruitment limitation and its role in species coexistence, testing the negative density-dependent hypothesis, and comparisons between seed rain and later life history phases (soil seed bank, seedling, sapling and adult). We recommend that

  5. Observations of total peroxy nitrates and total alkyl nitrates during the OP3 campaign: isoprene nitrate chemistry above a south-east Asian tropical rain forest

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    E. Aruffo

    2012-02-01

    Full Text Available Measurements of total peroxy nitrates (ΣRO2NO2, ΣPNs, total alkyl nitrates (ΣRONO2, ΣANs and nitrogen dioxide (NO2 were made above the surface of a Malaysian tropical rain forest in Borneo, using a laser-induced fluorescence instrument developed at the University of L'Aquila (Italy. This new instrument uses the direct excitation of NO2 at 532 nm in order to measure its concentrations detecting by the NO2 fluorescence at wavelengths longer than 610 nm. ΣPNs and ΣANs are indirectly measured after their thermal dissociation into NO2. Observations showed enhanced levels of NO2 during nighttime, an increase of ΣPNs during the afternoon and almost no evident diurnal cycle of ΣANs. The diurnal maximums of 200 pptv for ΣPNs and ΣANs are well below the peaks reported in other forest sites. A box model constrained with measured species, reproduces well the observed ΣPNs, but overestimates ΣANs concentrations. The reason of this model-observation discrepancy could be a wrong parameterization in the isoprene nitrates (INs chemistry mechanism. Sensitivity tests show that: (1 reducing the yield of INs from the reaction of peroxy nitrates with NO to almost the lowest values reported in literature (5%, (2 reducing the INs recycling to 70% and (3 keeping the INs dry deposition at 4 cm s−1, improve the agreement between modelled and measured ΣANs of 20% on average. These results imply that in the tropical rain forest, even if ΣPNs and ΣANs concentrations are lower than those observed in other North American forests, the yield and dry deposition of INs are similar. Another comparable result is that in the INs oxidation its recycling dominates with only a 30% release of NO2, which has implications on tropospheric ozone production and aerosol budget.

  6. Influences of canopy photosynthesis and summer rain pulses on root dynamics and soil respiration in a young ponderosa pine forest.

    Science.gov (United States)

    Misson, Laurent; Gershenson, Alexander; Tang, Jianwu; McKay, Megan; Cheng, Weixin; Goldstein, Allen

    2006-07-01

    Our first objective was to link the seasonality of fine root dynamics with soil respiration in a ponderosa pine (Pinus ponderosa P. & C. Lawson) plantation located in the Sierra Nevada of California. The second objective was to examine how canopy photosynthesis influences fine root initiation, growth and mortality in this ecosystem. We compared CO2 flux measurements with aboveground and belowground root dynamics. Initiation of fine root growth coincided with tree stem thickening and shoot elongation, preceding new needle growth. In the spring, root, shoot and stem growth occurred simultaneously with the increase in canopy photosynthesis. Compared with the other tree components, initial growth rate of fine roots was the highest and their growing period was the shortest. Both above and belowground components completed 90% of their growth by the end of July and the growing season lasted approximately 80 days. The period for optimal growth is short at the study site because of low soil temperatures during winter and low soil water content during summer. High photosynthetic rates were observed following unusual late-summer rains, but tree growth did not resume. The autotrophic contribution to soil respiration was 49% over the whole season, with daily contributions ranging between 18 and 87%. Increases in soil and ecosystem respiration were observed during spring growth; however, the largest variation in soil respiration occurred during summer rain events when no growth was observed. Both the magnitude and persistence of the soil respiration pulses were positively correlated with the amount of rain. These pulses accounted for 16.5% of soil respiration between Days 130 and 329.

  7. Quick assessment of wealth ants (Hymenoptera, Formicidae in rain forest fragments in the Alta Floresta region, MT

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    Jéssica Borges da Veiga

    2015-12-01

    Full Text Available Forest fragmentation can change the community and wealth of ants, through changes to the vegetation structure, solar radiation and food availability. This study aims to evaluate the generic richness of ants in two forest fragments in the municipality of Alta Floresta - MT. Samples were collected at three points of both fragments (interior, transition and surrounding matrix, being delimited one quadrant of 5x5 m for each point, using attractive bait. The ants were identified according to Baccaro (2006 identification key. For statistical diagnosis used the Multivariate analysis of conglomerates through BioEstat 5.0 software, and analyzed the similarities between subfamilies, genera and environments. The study found a total of 71 ants distributed in seven subfamilies and 12 genera, especially the genus Camponotus to occur mainly in disturbed habitats and Paraponera kind to occur in forest area. The transition environment was the least similar to the other due to a higher number of individuals and general wealth. In this study, the forest fragment 2 had a higher number of ants in their transition area and is considered the richest in ant fauna when compared to the forest fragment 1.

  8. Analysis of floristic composition and structure as an aid to monitoring protected areas of dense rain forest in southeastern Brazil

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    Eliana Cardoso-Leite

    2013-03-01

    Full Text Available To study forest composition and structure, as well as to facilitate management plans and monitoring programs, we conducted a phytosociological survey in the PE Caverna do Diabo State Park and the Quilombos do Médio Ribeira Environmentally Protected Area, both located within the state of São Paulo, Brazil. We analyzed 20 plots of 400 m² each, including only individuals with a circumference at breast height > 15 cm. We employed cluster analysis and ordination (principal component analysis and correspondence analysis, including species data and abiotic data. We evaluated 1051 individuals, belonging to 155 species in 48 families. Of those 155, 18 were threatened species, 33 were endemic species, and 92 (59.4% were secondary species. The overall Shannon index was 4.524, one of the highest recorded for a dense rainforest in southeastern Brazil. We found that our sample plots fell into three blocks. The first was forest in which there had been human disturbance, showing low species richness, minimal density, and a small relative quantity of biomass. The second was undisturbed mature forest, showing a comparatively larger quantity of biomass. The third was mature forest in which there had been natural intermediate disturbance (dead trees, showing higher species richness and greater density. We identified various groups of species that could be used in monitoring these distinct forest conditions.

  9. Why does air passage over forest yield more rain? Alternative interpretations of Spracklen et al. 2012 Nature 489: 282

    CERN Document Server

    Makarieva, Anastassia M; Sheil, Douglas; Nobre, Antonio D; Bunyard, Peter; Li, Bai-Lian

    2013-01-01

    Spracklen et al. recently presented a pan-tropical study of rainfall and land-cover that showed that satellite-derived rainfall measures were positively correlated with the degree to which model-derived air trajectories had been exposed to forest cover. This result confirms the influence of vegetation on regional rainfall patterns suggested in previous studies. However, we find that the conclusion of Spracklen et al. -- that differences in rainfall reflect air moisture content resulting from evapotranspiration -- appears undermined by methodological inconsistencies. We discuss some alternative explanations that require investigation. These include the distinct role of forest evapotranspiration in creating low pressure systems that draw moisture from the oceans to the continental hinterland. This alternative physical process is consistent with the empirical findings of Spracklen et al. but underlines a greater potential danger of forest loss than is suggested by their analyses of moisture recycling.

  10. Effect of acid rain on mercury leaching from forest yellow soil in Jinyun Mountain%酸雨对缙云山林地黄壤汞溶出的影响

    Institute of Scientific and Technical Information of China (English)

    李静; 魏世强; 杨学春

    2004-01-01

    Forest yellow soil and arable yellow soil in Jinyun Mountain were collected to study the effect of simulated acid rain(adjusted to pH 2.0, 3.0, 4.0 and 5.0) on the Hg leaching from soils by the methods of static extraction and dynamic leaching. The results showed that in forest yellow soils, surface accumulation of Hg occurred, and the accumulated Hg was easier to be leached out than that in arable yellow soil by acid rain. The amount of leached Hg was the largest at pH 4.0. To abate the risk of Hg pollution in water bodies by the Hg leaching from this forest soil, the Mountain should be closed, and timber-felling should be forbidden.

  11. Cocoa Intensification Scenarios and Their Predicted Impact on CO2 Emissions, Biodiversity Conservation, and Rural Livelihoods in the Guinea Rain Forest of West Africa

    Science.gov (United States)

    Gockowski, Jim; Sonwa, Denis

    2011-08-01

    The Guinean rain forest (GRF) of West Africa, identified over 20 years ago as a global biodiversity hotspot, had reduced to 113,000 km2 at the start of the new millennium which was 18% of its original area. The principal driver of this environmental change has been the expansion of extensive smallholder agriculture. From 1988 to 2007, the area harvested in the GRF by smallholders of cocoa, cassava, and oil palm increased by 68,000 km2. Field results suggest a high potential for significantly increasing crop yields through increased application of seed-fertilizer technologies. Analyzing land-use change scenarios, it was estimated that had intensified cocoa technology, already developed in the 1960s, been pursued in Cote d'Ivoire, Ghana, Nigeria and Cameroon that over 21,000 km2 of deforestation and forest degradation could have been avoided along with the emission of nearly 1.4 billion t of CO2. Addressing the low productivity of agriculture in the GRF should be one of the principal objectives of REDD climate mitigation programs.

  12. Reproductive phenology, pollination, and fructification of Heliconia spathocircinata Aristeg. (Heliconiaceae in an Atlantic Rain Forest fragment in Rio de Janeiro City

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    Caio César Corrêa Missagia

    2011-09-01

    Full Text Available Aspects of phenology and reproductive biology of Heliconia spathocircinata Aristeg. in border and interior areas of an Atlantic Rain Forest fragment in Rio de Janeiro City, Brazil, are apresented. Four plots of 10x10m were delineated, two on the edge and two inside the forest, and individuals of H. spathocircinata were monitored from June 2009 to June 2010. The observations were carried out from 6 a.m. to 6 p.m. once a week on December and January, and fortnightly the rest of flowering. Heliconia spathocircinata bloomeds between November and March and the fruits were ripe two months after pollination, and there was no significant difference between edge and interior with regard to the period of flowering and fruiting. The fruit-flower ratio averaged 66.6% in the interior and 27% within the forestedge, a considerable difference. The male hummingbirds Thalurania glaucopis Gmelin, and to a lesser extent, female birds of this species, were the most frequent pollinators in the area evaluated, both edge and interior. Other species were identified as pollinators: Phaethornis ruber L., Ramphodon naevius Dumont, Eupetomena macroura Gmelin, and Amazilia fimbriata Gmelin. Of these, only P. ruber was found in both environments.

  13. Light-related variation in sapling architecture of three shade-tolerant tree species of the Mexican rain forest

    NARCIS (Netherlands)

    Martinez-Sanchez, J.L.; Meave, J.; Bongers, F.

    2008-01-01

    The crown architecture of three shade-tolerant tree species (two subcanopy and one mid-canopy) was analyzed in relation to the light regime of the forest understorey. The aim was to examine to which extent shade-tolerant species variate in their crown architecture. Tree saplings (265) between 50 and

  14. Midday dew--an overlooked factor enhancing photosynthetic activity of corticolous epiphytes in a wet tropical rain forest.

    Science.gov (United States)

    Lakatos, Michael; Obregón, André; Büdel, Burkhard; Bendix, Jörg

    2012-04-01

    • Additional water supplied by dew formation is an important resource for microbes, plants and animals in precipitation-limited habitats, but has received little attention in tropical forests until now. • We evaluated the micro-environmental conditions of tree stem surfaces and their epiphytic organisms in a neotropical forest, and present evidence for a novel mechanism of diurnal dew formation on these surfaces until midday that has physiological implications for corticolous epiphytes such as lichens. • In the understorey of a lowland forest in French Guiana, heat storage of stems during the day and delayed radiative loss during the night decreased stem surface temperatures by 6°C in comparison to the dew-point temperature of ambient air. This measured phenomenon induced modelled totals of diurnal dew formation between 0.29 and 0.69 mm d⁻¹ on the surface of the bark and the lichens until early afternoon. • Crustose lichens substantially benefit from this dew formation, because it prolongs photosynthetic activity. This previously unrecognized mechanism of midday dew formation contributes to the water supply of most corticolous organisms, and may be a general feature in forest habitats world-wide.

  15. Whither Acid Rain?

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    Peter Brimblecombe

    2000-01-01

    Full Text Available Acid rain, the environmental cause célèbre of the 1980s seems to have vanished from popular conscience. By contrast, scientific research, despite funding difficulties, has continued to produce hundreds of research papers each year. Studies of acid rain taught much about precipitation chemistry, the behaviour of snow packs, long-range transport of pollutants and new issues in the biology of fish and forested ecosystems. There is now evidence of a shift away from research in precipitation and sulfur chemistry, but an impressive theoretical base remains as a legacy.

  16. Soil changes induced by rubber and tea plantation establishment: comparison with tropical rain forest soil in Xishuangbanna, SW China.

    Science.gov (United States)

    Li, Hongmei; Ma, Youxin; Liu, Wenjie; Liu, Wenjun

    2012-11-01

    Over the past thirty years, Xishuangbanna in Southwestern China has seen dramatic changes in land use where large areas of tropical forest and fallow land have been converted to rubber and tea plantations. In this study we evaluated the effects of land use and slope on soil properties in seven common disturbed and undisturbed land-types. Results indicated that all soils were acidic, with pH values significantly higher in the 3- and 28-year-old rubber plantations. The tropical forests had the lowest bulk densities, especially significantly lower from the top 10 cm of soil, and highest soil organic matter concentrations. Soil moisture content at topsoil was highest in the mature rubber plantation. Soils in the tropical forests and abandoned cultivated land had inorganic N (IN) concentrations approximately equal in NH(4) (+)-N and NO(3) (-)-N. However, soil IN pools were dominated by NH(4) (+)-N in the rubber and tea plantations. This trend suggests that conversion of tropical forest to rubber and tea plantations increases NH(4) (+)-N concentration and decreases NO(3) (-)-N concentration, with the most pronounced effect in plantations that are more frequently fertilized. Soil moisture content, IN, NH(4) (+)-N and NO(3) (-)-N concentrations within all sites were higher in the rainy season than in the dry season. Significant differences in the soil moisture content, and IN, NH(4) (+)-N and NO(3) (-)-N concentration was detected for both land uses and sampling season effects, as well as interactions. Higher concentrations of NH(4) (+)-N were measured at the upper slopes of all sites, but NO(3) (-)-N concentrations were highest at the lower slope in the rubber plantations and lowest at the lower slopes at all other. Thus, the conversion of tropical forests to rubber and tea plantations can have a profound effect on soil NH(4) (+)-N and NO(3) (-)-N concentrations. Options for improved soil management in plantations are discussed.

  17. An ant-plant by-product mutualism is robust to selective logging of rain forest and conversion to oil palm plantation.

    Science.gov (United States)

    Fayle, Tom M; Edwards, David P; Foster, William A; Yusah, Kalsum M; Turner, Edgar C

    2015-06-01

    Anthropogenic disturbance and the spread of non-native species disrupt natural communities, but also create novel interactions between species. By-product mutualisms, in which benefits accrue as side effects of partner behaviour or morphology, are often non-specific and hence may persist in novel ecosystems. We tested this hypothesis for a two-way by-product mutualism between epiphytic ferns and their ant inhabitants in the Bornean rain forest, in which ants gain housing in root-masses while ferns gain protection from herbivores. Specifically, we assessed how the specificity (overlap between fern and ground-dwelling ants) and the benefits of this interaction are altered by selective logging and conversion to an oil palm plantation habitat. We found that despite the high turnover of ant species, ant protection against herbivores persisted in modified habitats. However, in ferns growing in the oil palm plantation, ant occupancy, abundance and species richness declined, potentially due to the harsher microclimate. The specificity of the fern-ant interactions was also lower in the oil palm plantation habitat than in the forest habitats. We found no correlations between colony size and fern size in modified habitats, and hence no evidence for partner fidelity feedbacks, in which ants are incentivised to protect fern hosts. Per species, non-native ant species in the oil palm plantation habitat (18 % of occurrences) were as important as native ones in terms of fern protection and contributed to an increase in ant abundance and species richness with fern size. We conclude that this by-product mutualism persists in logged forest and oil palm plantation habitats, with no detectable shift in partner benefits. Such persistence of generalist interactions in novel ecosystems may be important for driving ecosystem functioning.

  18. Erosion on tropical rain-forest terrain: a re-evaluation in the light of long-term monitoring, aerial photographic evidence and sediment fingerprinting in Borneo

    Science.gov (United States)

    Walsh, Rory; Bidin, Kawi; Blake, William; Clarke, Michelle; Sayer, Aimee; Ghazali, Rosmadi; Annammala, Kogila; Chappell, Nick; Douglas, Ian

    2010-05-01

    Rain-forest vegetation is generally considered to be highly protective against erosion, but with disturbance via logging leading to major, but relatively short-lived increases in erosion for a 2-year period until rapid revegetation of slopes has occurred. This paper questions and re-assesses these views using a combination of long-term monitoring, GIS-assisted aerial photograph analysis and multi-proxy sediment fingerprinting in primary rainforest and adjacent terrain that was selectively logged either in 1988-89 or in 1992-93 within the Segama catchment in eastern Sabah, Malaysian Borneo. In primary forest areas, repeat measurements using the erosion bridge technique over the 20-year period 1990-2010 demonstrate how slopewash rates are significant, but concentrated in extreme events and increasing sharply with slope angle. Continuous monitoring of suspended sediment, coupled with repeat erosion bridge measurement, however, demonstrate that pipe erosion is at least as important even on moderate terrain and landsliding is an important process on steep terrain. In the selectively logged Baru catchment, a combination of long-term monitoring of suspended sediment and repeat measurements at an erosion bridge network has demonstrated that the erosional impact of logging is longer-term than formerly thought, with a major secondary peak in erosion 5-10 years after logging due to road-linked landslides and the decay of logs in debris dams; analysis of current bed-sediment and floodplain cores using a multi-proxy sediment fingerprinting approach demonstrates that sources of sediment are still different to those in primary forest over 20 years after logging ceased. Sediment fingerprinting at the large catchment scale (focussing on the analysis of lateral bench and floodplain sediment cores compared with upstream tributary sediment inputs), together with GIS-assisted analysis of aerial photographic evidence of spatial differences in landslide occurrence, demonstrates the key

  19. Effects of simulated acid rain on soil and soil solution chemistry in a monsoon evergreen broad-leaved forest in southern China.

    Science.gov (United States)

    Qiu, Qingyan; Wu, Jianping; Liang, Guohua; Liu, Juxiu; Chu, Guowei; Zhou, Guoyi; Zhang, Deqiang

    2015-05-01

    Acid rain is an environmental problem of increasing concern in China. In this study, a laboratory leaching column experiment with acid forest soil was set up to investigate the responses of soil and soil solution chemistry to simulated acid rain (SAR). Five pH levels of SAR were set: 2.5, 3.0, 3.5, 4.0, and 4.5 (as a control, CK). The results showed that soil acidification would occur when the pH of SAR was ≤3.5. The concentrations of NO₃(-)and Ca(2+) in the soil increased significantly when the pH of SAR fell 3.5. The concentration of SO₄(2-) in the soil increased significantly when the pH of SAR was acidity of SAR. The releases of soluble Al and Fe were SAR pH dependent, and their net exports under pH 2.5 treatment were 19.6 and 5.5 times, respectively, higher than that under CK. The net export of DOC was reduced by 12-29% under SAR treatments as compared to CK. Our results indicate the chemical constituents in the soil are more sensitive to SAR than those in the soil solution, and the effects of SAR on soil solution chemistry depend not only on the intensity of SAR but also on the duration of SAR addition. The soil and soil solution chemistry in this region may not be affected by current precipitation (pH≈4.5) in short term, but the soil and soil leachate chemistry may change dramatically if the pH of precipitation were below 3.5 and 3.0, respectively.

  20. Spatial structure and the effects of host and soil environments on communities of ectomycorrhizal fungi in wooded savannas and rain forests of Continental Africa and Madagascar.

    Science.gov (United States)

    Tedersoo, Leho; Bahram, Mohammad; Jairus, Teele; Bechem, Eneke; Chinoya, Stephen; Mpumba, Rebecca; Leal, Miguel; Randrianjohany, Emile; Razafimandimbison, Sylvain; Sadam, Ave; Naadel, Triin; Kõljalg, Urmas

    2011-07-01

    Mycorrhizal fungi play a key role in mineral nutrition of terrestrial plants, but the factors affecting natural distribution, diversity and community composition of particularly tropical fungi remain poorly understood. This study addresses shifts in community structure and species frequency of ectomycorrhizal (EcM) fungi in relation to host taxa, soil depth and spatial structure in four contrasting African ecosystems. We used the rDNA and plastid trnL intron sequence analysis for identification of fungi and host plants, respectively. By partitioning out spatial autocorrelation in plant and fungal distribution, we suggest that African EcM fungal communities are little structured by soil horizon and host at the plant species and family levels. These findings contrast with patterns of vegetation in these forests and EcM fungal communities in other tropical and temperate ecosystems. The low level of host preference indirectly supports an earlier hypothesis that pioneer Phyllanthaceae may facilitate the establishment of late successional Fabaceae and potentially other EcM host trees by providing compatible fungal inoculum in deforested and naturally disturbed ecosystems of tropical Africa.

  1. Fine scale spatial genetic structure in Pouteria reticulata (Engl. Eyma (Sapotaceae, a dioecious, vertebrate dispersed tropical rain forest tree species

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    John W. Schroeder

    2014-08-01

    Full Text Available Dioecious tropical tree species often have small flowers and fleshy fruits indicative of small-insect pollination and vertebrate seed dispersal. We hypothesize that seed mediated gene flow should be exceed pollen-mediated gene flow in such species, leading to weak patterns of fine scale spatial genetic structure (SGS. In the present study, we characterize novel microsatellite DNA markers and test for SGS in sapling (N=100 and adult trees (N=99 of the dioecious canopy tree Pouteria reticulata (Sapotaceae in a 50 ha forest dynamics plot on Barro Colorado Island (BCI, Panama. The five genetic markers contained between five and 15 alleles per locus, totaling 51 alleles in the sample population. Significant SGS at local spatial scales (<100m was detected in the sapling (dbh≈1cm and adult (dbh≥20cm size classes, but was stronger in the former (sapling Sp=0.010±0.004, adult Sp=0.006±0.002, suggesting demographic thinning. The degree of SGS was lower than the value expected for non-vertebrate dispersed tropical trees (Sp=0.029, but similar to the average value for vertebrate dispersed tropical trees (Sp=0.009 affirming the dispersal potential of vertebrate dispersed tropical trees in faunally intact forests.

  2. Low abundance of long-tongued pollinators leads to pollen limitation in four specialized hawkmoth-pollinated plants in the Atlantic Rain forest, Brazil

    Science.gov (United States)

    Amorim, Felipe W.; Wyatt, Graham E.; Sazima, Marlies

    2014-11-01

    Long-tubed hawkmoth-pollinated species present some of the most remarkable examples of floral specialization depending exclusively on long-tongued hawkmoths for sexual reproduction. Nonetheless, long-tongued hawkmoths do not rely exclusively on specialized plants as nectar sources, which may limit sexual reproduction through pollen limitation. However, very few studies have quantified the level of pollen limitation in plants with highly specialized floral traits in tropical regions. In this context, we studied four sympatric hawkmoth-pollinated species in a highland Atlantic Rain forest and assessed pollen limitation and their dependence on pollinators by analyzing the floral biology, breeding system, pollination mechanisms, and abundance of long-tongued pollinators. We showed that the four species are self-compatible, but are completely dependent on long-tongued hawkmoths to set fruits, and that flower visitation was infrequent in all plant species. Pollen limitation indices ranged from 0.53 to 0.96 showing that fruit set is highly limited by pollen receipt. Long-tongued moths are much less abundant and comprise only one sixth of the hawkmoth fauna. Pollen analyses of 578 sampled moths revealed that hawkmoths visited ca. 80 plant species in the community, but only two of the four species studied. Visited plants included a long-tubed hawkmoth-pollinated species endemic to the lowland forest ca. 15-20 km away from the study site. Specialization index ( H 2 ' = 0.20) showed that community-level interactions between hawkmoths and plants are generalized. We suggest that sexual reproduction of these highly specialized hawkmoth-pollinated species is impaired by competition among plants for pollinators, in conjunction with the low abundance and diversity of long-tongued pollinators.

  3. Sea Surface Temperatures Mediated by the El Niño-Southern Oscillation Affect Birds Breeding in Temperate Coastal Rain Forests

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    Anthony J. Gaston

    2005-12-01

    Full Text Available We studied the timing of breeding and juvenile/adult ratios among songbirds in temperate rain forests over four years on the Haida Gwaii (Queen Charlotte Islands archipelago, British Columbia. In May 1998, air temperatures in Haida Gwaii were above average, whereas in 1999 they were the lowest in 20 yr: temperatures in the other two years were closer to normal, although 2001 was almost as cold as 1999. Temperatures closely followed the patterns of sea surface temperatures created by the 1997–1998 El Niño, i.e., warm, event and the subsequent strong La Niña, i.e., cool, event. Timing of breeding, as measured by the first capture of juveniles or by direct observations of hatching, varied by approximately 19 d between the earliest (1998 and latest (1999 years. In 1998, the proportion of juveniles among birds trapped increased steeply as soon as young birds began to appear. In other years, the rate of increase was slower. In 1999, the peak proportions of hatching-year individuals among the foliage-gleaning insectivores, i.e., the Orange-crowned Warbler (Vermivora celata, Townsend's Warbler (Dendroica townsendi, and the Golden-crowned Kinglet (Regulus satrapa, were lower than in other years, with almost no young Orange-crowned Warblers captured at all. The pattern of variation in the timing of breeding and in the proportion of hatching-year individuals trapped fitted the temperature data well, although rainfall may also have contributed. We concluded that changes mediated by El Niño-Southern Oscillation (ENSO in sea surface temperatures off northern British Columbia, through their effects on air temperatures, had a strong effect on the breeding of forest birds, to the point of causing nearly complete reproductive failure for one species in 1999. An intensification of the ENSO cycle could lead to more erratic reproduction for some species.

  4. Changes in soil carbon and nutrients following 6 years of litter removal and addition in a tropical semi-evergreen rain forest

    Science.gov (United States)

    Tanner, Edmund Vincent John; Sheldrake, Merlin W. A.; Turner, Benjamin L.

    2016-11-01

    Increasing atmospheric CO2 and temperature may increase forest productivity, including litterfall, but the consequences for soil organic matter remain poorly understood. To address this, we measured soil carbon and nutrient concentrations at nine depths to 2 m after 6 years of continuous litter removal and litter addition in a semi-evergreen rain forest in Panama. Soils in litter addition plots, compared to litter removal plots, had higher pH and contained greater concentrations of KCl-extractable nitrate (both to 30 cm); Mehlich-III extractable phosphorus and total carbon (both to 20 cm); total nitrogen (to 15 cm); Mehlich-III calcium (to 10 cm); and Mehlich-III magnesium and lower bulk density (both to 5 cm). In contrast, litter manipulation did not affect ammonium, manganese, potassium or zinc, and soils deeper than 30 cm did not differ for any nutrient. Comparison with previous analyses in the experiment indicates that the effect of litter manipulation on nutrient concentrations and the depth to which the effects are significant are increasing with time. To allow for changes in bulk density in calculation of changes in carbon stocks, we standardized total carbon and nitrogen on the basis of a constant mineral mass. For 200 kg m-2 of mineral soil (approximately the upper 20 cm of the profile) about 0.5 kg C m-2 was "missing" from the litter removal plots, with a similar amount accumulated in the litter addition plots. There was an additional 0.4 kg C m-2 extra in the litter standing crop of the litter addition plots compared to the control. This increase in carbon in surface soil and the litter standing crop can be interpreted as a potential partial mitigation of the effects of increasing CO2 concentrations in the atmosphere.

  5. A reconstruction of Atlantic Central African biomes and forest succession stages derived from modern pollen data and plant functional types

    Directory of Open Access Journals (Sweden)

    J. Lebamba

    2009-01-01

    Full Text Available New detailed vegetation reconstructions are proposed in Atlantic Central Africa from a modern pollen data set derived from 199 sites (Cameroon, Gabon and Congo including 131 new sites. In this study, the concept of plant functional classification is improved with new and more detailed plant functional types (PFTs and new aggregations of pollen taxa. Using the biomisation method, we reconstructed (1 modern potential biomes and (2 potential succession stages of forest regeneration, a new approach in Atlantic Central African vegetation dynamics and ecosystem functioning reconstruction. When compared to local vegetation, potential biomes are correctly reconstructed (97.5% of the sites and tropical evergreen to semi-evergreen forest (TRFO biome is well identified from semi-deciduous forest (TSFO biome. When the potential biomes are superimposed on the White's vegetation map, only 76.4% of the sites are correctly reconstructed. But using botanical data, correspondence and cluster analyses, the 43 sites from Congo (Mayombe evidence more affinities with those of central Gabon and so they can also be considered as correctly reconstructed as TRFO biome and White's map must be revised. In terms of potential succession stages of forest regeneration, the mature forest (TMFO is well differentiated from the secondary forest (TSFE, but inside this latter group, the young and the pioneer stages are not clearly identified due probably to their low sampling representation. Moreover, linked to their progressive and mosaic character, the boundaries between two forest biomes or two forest stages are not clearly detected and need also a more intensive sampling in such transitions.

  6. Fruit flies (Diptera, Tephritidae) and their associations with native host plants in a remnant area of the highly endangered Atlantic Rain Forest in the State of Espírito Santo, Brazil.

    Science.gov (United States)

    Uramoto, K; Martins, D S; Zucchi, R A

    2008-10-01

    The results presented in this paper refer to a host survey, lasting approximately three and a half years (February 2003-July 2006), undertaken in the Vale do Rio Doce Natural Reserve, a remnant area of the highly endangered Atlantic Rain Forest located in Linhares County, State of Espírito Santo, Brazil. A total of 330 fruit samples were collected from native plants, representing 248 species and 51 plant families. Myrtaceae was the most diverse family with 54 sampled species. Twenty-eight plant species, from ten families, are hosts of ten Anastrepha species and of Ceratitis capitata (Wiedemann). Among 33 associations between host plants and fruit flies, 20 constitute new records, including the records of host plants for A. fumipennis Lima and A. nascimentoi Zucchi. The findings were discussed in the light of their implications for rain forest conservation efforts and the study of evolutionary relationships between fruit flies and their hosts.

  7. Differential acetyl cholinesterase inhibition by volatile oils from two specimens of Marlierea racemosa (Myrtaceae) collected from different areas of the Atlantic Rain Forest.

    Science.gov (United States)

    Souza, Amanda; Silva, Michelle C; Cardoso-Lopes, Elaine M; Cordeiro, Inês; Sobral, Marcos E G; Young, Maria Cláudia M; Moreno, Paulo R H

    2009-08-01

    The volatile oil composition and anti-acetyl cholinesterase activity were analyzed in two specimens of Marlierea racemosa growing in different areas of the Atlantic Rain Forest (Cananéia and Caraguatatuba, SP, Brazil). Component identifications were performed by GC/MS and their acetyl cholinesterase inhibitory activity was measured through colorimetric analysis. The major constituent in both specimens was spathulenol (25.1% in Cananéia and 31.9% in Caraguatatuba). However, the first one also presented monoterpenes (41.2%), while in the Carguatatuba plants, this class was not detected. The oils from the plants collected in Cananéia were able to inhibit the acetyl cholinesterase activity by up to 75%, but for oils from the other locality the maximal inhibition achieved was 35%. These results suggested that the monoterpenes are more effective in the inhibition of acetyl cholinesterase activity than sesquiterpenes as these compounds are present in higher amounts in the M. racemosa plants collected in Cananéia.

  8. Structural characterization and molecular identification of arbuscular mycorrhiza morphotypes of Alzatea verticillata (Alzateaceae), a prominent tree in the tropical mountain rain forest of South Ecuador.

    Science.gov (United States)

    Beck, Adela; Haug, Ingeborg; Oberwinkler, Franz; Kottke, Ingrid

    2007-10-01

    The vast majority of the highly diverse trees in the tropical mountain rain forest of South Ecuador form arbuscular mycorrhizas, and previous molecular investigations revealed a high diversity of fungi. In this study, we present a first trial to link fungal DNA-sequences with defined morphotypes characterized on the basis of partly new mycelial features obtained from field material of one tree species, Alzatea verticillata. Fine roots were halved lengthwise to study the mycelium anatomy on one half and to obtain fungal nuclear rDNA coding for the small subunit rRNA of Glomeromycota from the other half. Light microscopy revealed conspicuously large amounts of mycelium attaching to the surface of the rootlets. The mycelium formed fine- or large-branched appressoria-like plates, vesicles of regular or irregular shape, and very fine, multibranched structures ensheathed by septate hyphae. These previously undescribed features of the supraradical mycelia combined with intraradical mycelium structures were used for distinguishing of four main morphogroups and subordinate 14 morphotypes. DNA sequences of Glomus group A, Acaulospora and Gigaspora, were obtained and linked to three morphogroups. Two sequence types within Glomus group A could be tentatively associated to subordinate morphotypes.

  9. Dero (Allodero lutzi Michaelsen, 1926 (Oligochaeta: Naididae associated with Scinax fuscovarius (Lutz, 1925 (Anura: Hylidae from Semi-deciduous Atlantic Rain Forest, southern Brazil

    Directory of Open Access Journals (Sweden)

    FH. Oda

    Full Text Available Amphibians are hosts for a wide variety of ecto- and endoparasites, such as protozoans and parasitic worms. Naididae is a family of Oligochaeta whose species live on a wide range of substrates, including mollusks, aquatic macrophytes, sponges, mosses, liverworts, and filamentous algae. However, some species are known as endoparasitic from vertebrates, such as Dero (Allodero lutzi, which is parasitic of the urinary tracts of frogs, but also have a free-living stage. Specimens in the parasitic stage lack dorsal setae, branchial fossa, and gills. Here we report the occurrence of D. (A. lutzi associated with anuran Scinax fuscovarius from Semi-deciduous Atlantic Rain Forest in southern Brazil. The study took place at the Caiuá Ecological Station, Diamante do Norte, Paraná, southern Brazil. Seven specimens of S. fuscovarius were examined for parasites but only one was infected. Parasites occurred in ureters and urinary bladder. Previous records of this D. (A. lutzi include the Brazilian States of Santa Catarina, São Paulo, Rio de Janeiro, and Minas Gerais, as well as Cuba and North America. This is a new locality record for this species in Brazil. Reports of Dero (Allodero lutzi are rare, due to difficulty of observation, and such events are restricted only the fortuitous cases. It is important to emphasize the necessity of future studies, which are fundamental to the understanding of biological and ecological aspects of this species.

  10. Spatial and temporal scaling of intercellular CO2 concentration in a temperate rain forest dominated by Dacrydium cupressinum in New Zealand.

    Science.gov (United States)

    Tissue, David T; Barbour, Margaret M; Hunt, John E; Turnbull, Matthew H; Griffin, Kevin L; Walcroft, Adrian S; Whitehead, David

    2006-04-01

    Seven methods, including measurements of photosynthesis (A) and stomatal conductance (g(s)), carbon isotope discrimination, ecosystem CO2 and water vapour exchange using eddy covariance and the use of a multilayer canopy model and ecosystem Keeling plots, were employed to derive estimates of intercellular CO2 concentration (Ci) across a range of spatial and temporal scales in a low productivity rain forest ecosystem dominated by the conifer Dacrydium cupressinum Lamb. in New Zealand. Estimates of shoot and canopy Ci across temporal scales ranging from minutes to years were remarkably similar (range of 274-294 micromol mol(-1)). The gradual increase in shoot Ci with depth in the canopy was more likely attributable to decreases in A resulting from lower irradiance (Q) than to increases in g, due to changes in air saturation deficit (D). The lack of marked vertical gradients in A and g(s) at saturating Q through the canopy and the low seasonal variability in environmental conditions contributed to the efficacy of scaling Ci. However, the canopy Ci estimate calculated from the carbon isotope composition of respired ecosystem CO2 (delta13CR; 236 micromol mol(-1)) was much lower than other estimates of canopy Ci. Partitioning delta13CR into four components (soil, roots, litter and foliage) indicated root respiration as the dominant (> 50%) contributor to delta13CR. Variable time lags and differences in isotopic composition during photosynthesis and respiration make the direct estimation of canopy Ci from delta 13CR problematic.

  11. Woody plants of Western African forests, A guide to the forest trees, shrubs and lianes from Senegal to Ghana

    NARCIS (Netherlands)

    Hawthorne, W.D.; Jongkind, C.C.H.

    2006-01-01

    A guide to the identification of all the woody plants (c. 2,250 species in 740 genera) of the forest region of West Africa called 'Upper Guinea', between Togo and Senegal. Upper Guinea is one of the world's most important centres of biodiversity, from the mountain forests of Liberia, Guinea and Sier

  12. Comparing functional similarity between a native and an alien slug in temperate rain forests of British Columbia

    Directory of Open Access Journals (Sweden)

    Mariano A. Rodriguez-Cabal

    2015-04-01

    Full Text Available The impacts of invasive alien species are greatest when they become dominant members of a community, introduce novel traits, and displace native species. Invasions by alien mollusks represent a novel context by which to compare trait differences between generalist native and introduced herbivores in terrestrial ecosystems. Here, we determined the abundance, habitat, feeding preferences, as well as the metabolic rate of the native Pacific banana slug (Ariolimax columbianus and the alien black slug (Arion rufus in the coastal forests of British Columbia, Canada. Through a series of observational and experimental studies, we found that alien slugs are more abundant, differ in their habitat preferences, and consumed more fungi (mushrooms than native banana slugs. Conversely, in an enclosures experiment we found that herbivory damage by native slugs was higher compared to enclosures with alien only and control enclosures. Finally, metabolic rates were similar for both slug species. These results suggest that alien black slugs possess a suite of traits that make them functionally different from native banana slugs.

  13. Diversity and network structure of invertebrate communities associated to Heliconia species in natural and human disturbed tropical rain forests

    Directory of Open Access Journals (Sweden)

    Julieta Benítez-Malvido

    2014-12-01

    Full Text Available We analyzed the influence of natural and anthropogenic habitat disturbance on the structure of invertebrate communities living on two species of Heliconia herbs. We compared the invertebrate community structure associated to both species growing in natural forest gaps, on road edges for H. latispatha, and in riparian vegetation for H. collinsiana. We assessed the topological structure of individual-based Heliconia–invertebrate networks. Species richness was greater in H. collinsiana inhabiting riparian vegetation but no differences were found in the diversity of invertebrates for any Heliconia species and habitat. Invertebrate abundance was greater in gaps for H. latispatha and in riparian vegetation for H. collinsiana showing a species turnover in human disturbed habitats. The invertebrate community was not randomly assembled but highly nested, revealing a structured pattern for all habitat conditions. Heliconia–invertebrate network properties appear to be maintained in human disturbed habitats, despite differences in species richness, abundance and composition and host number and quality. Our study contributes to the understanding of the structure of ecological interactions in contrasting habitats. Because they provide food and habitat for the associated fauna and several microhabitats for colonization, heliconias could be used as habitat elements for invertebrate conservation in human impacted landscapes.

  14. New estimates of temperature response of leaf photosynthesis in Amazon forest trees, its acclimation to mean temperature change and consequences for modelling climate response to rain forests.

    Science.gov (United States)

    Kruijt, B.; Jans, W.; Vasconcelos, S.; Tribuzy, E. S.; Felsemburgh, C.; Eliane, M.; Rowland, L.; da Costa, A. C. L.; Meir, P.

    2014-12-01

    In many dynamic vegetation models, degradation of the tropical forests is induced because they assume that productivity falls rapidly when temperatures rise in the region of 30-40°C. Apart plant respiration, this is due to the assumptions on the temperature optima of photosynthetic capacity, which are low and can differ widely between models, where in fact hardly any empirical information is available for tropical forests. Even less is known about the possibility that photosynthesis will acclimate to changing temperatures. The objective of this study to is to provide better estimates for optima, as well as to determine whether any acclimation to temperature change is to be expected. We present both new and hitherto unpublished data on the temperature response of photosynthesis of Amazon rainforest trees, encompassing three sites, several species and five field campaigns. Leaf photosynthesis and its parameters were determined at a range of temperatures. To study the long-term (seasonal) acclimation of this response, this was combined with an artificial, in situ, multi-season leaf heating experiment. The data show that, on average for all non-heated cases, the photosynthetic parameter Vcmax weakly peaks between 35 and 40 ˚C, while heating does not have a clearly significant effect. Results for Jmax are slightly different, with sharper peaks. Scatter was relatively high, which could indicate weak overall temperature dependence. The combined results were used to fit new parameters to the various temperature response curve functions in a range of DGVMs. The figure shows a typical example: while the default Jules model assumes a temperature optimum for Vcmax at around 33 ˚C, the data suggest that Vcmax keeps rising up to at least 40 ˚C. Of course, calculated photosynthesis, obtained by applying this Vcmax in the Farquhar model, peaks at lower temperature. Finally, the implication of these new model parameters for modelled climate change impact on modelled Amazon

  15. Effects of forest fragmentation and habitat degradation on West African leaf-litter frogs

    NARCIS (Netherlands)

    Hillers, A.; Veith, M.; Rödel, M.-O.

    2008-01-01

    Habitat degradation alters the dynamics and composition of anuran assemblages in tropical forests. The effects of forest fragmentation on the composition of anuran assemblages are so far poorly known. We studied the joint influence of forest fragmentation and degradation on leaf-litter frogs. We spe

  16. Photosynthesis in relation to leaf nitrogen, phosphorus and specific leaf area of seedlings and saplings in tropical montane rain forests of Hainan Island, south China

    Institute of Scientific and Technical Information of China (English)

    Fude LIU; Ming ZHANG; Wenjin WANG; Shuning CHEN; Jianwei ZHENG; Wenjie YANG; Fengqin HU; Shuqing AN

    2009-01-01

    In order to make clear the relationships between photosynthesis and leaf N, leaf P and SLA of tropical trees, and test the differences in the relationships among life-form groups (trees, shrub-like trees and shrubs),seedlings and saplings of 101 species from a tropical montane rain forest, located in the Diaoluo Mountain of Hainan Island, were selected. The net photosynthesis based on area and mass (Aarea and Amass), leaf nitrogen content based on area and mass (Narea and Nmass), leaf phosphorus content based on area and mass (Parea and Pmass) and specific leaf area (SLA) were measured and/or calculated.The results showed that Aarea and Amass tended to follow the order of shrubs > trees > shrub-like trees. One-way ANOVA showed that the difference in Aarea between shrubs and shrub-like trees was significant (p 0.05). The relationship between Aarea and SLAwas highly significant in shrubs (p = 0.0006),trees (p 0.05). The relationships between Amass and leaf N and SLA were highly significant in all three life-form groups and for all species (p < 0.0001). For Amass and leaf P, there were significant correlations in tree groups (p =0.0377) and highly significant correlations in shrub groups (p = 0.0004), shrub-like tree groups (p = 0.0018) and for all species (p < 0.0001). Stepwise regression showed that predicted Amass values were closer to the observed values than those for predicted Aarea values. Thus, it can be concluded that the relationships obtained from seedling and sapling measurements are close to those from mature individuals; correlations between photosynthesis and Nmass, Pmass and SLA traits are significant and the relationships are stronger and more stable for A mass than for Aarea.

  17. Long-term observations of cloud condensation nuclei in the Amazon rain forest - Part 1: Aerosol size distribution, hygroscopicity, and new model parametrizations for CCN prediction

    Science.gov (United States)

    Pöhlker, Mira L.; Pöhlker, Christopher; Ditas, Florian; Klimach, Thomas; Hrabe de Angelis, Isabella; Araújo, Alessandro; Brito, Joel; Carbone, Samara; Cheng, Yafang; Chi, Xuguang; Ditz, Reiner; Gunthe, Sachin S.; Kesselmeier, Jürgen; Könemann, Tobias; Lavrič, Jošt V.; Martin, Scot T.; Mikhailov, Eugene; Moran-Zuloaga, Daniel; Rose, Diana; Saturno, Jorge; Su, Hang; Thalman, Ryan; Walter, David; Wang, Jian; Wolff, Stefan; Barbosa, Henrique M. J.; Artaxo, Paulo; Andreae, Meinrat O.; Pöschl, Ulrich

    2016-12-01

    Size-resolved long-term measurements of atmospheric aerosol and cloud condensation nuclei (CCN) concentrations and hygroscopicity were conducted at the remote Amazon Tall Tower Observatory (ATTO) in the central Amazon Basin over a 1-year period and full seasonal cycle (March 2014-February 2015). The measurements provide a climatology of CCN properties characteristic of a remote central Amazonian rain forest site.The CCN measurements were continuously cycled through 10 levels of supersaturation (S = 0.11 to 1.10 %) and span the aerosol particle size range from 20 to 245 nm. The mean critical diameters of CCN activation range from 43 nm at S = 1.10 % to 172 nm at S = 0.11 %. The particle hygroscopicity exhibits a pronounced size dependence with lower values for the Aitken mode (κAit = 0.14 ± 0.03), higher values for the accumulation mode (κAcc = 0.22 ± 0.05), and an overall mean value of κmean = 0.17 ± 0.06, consistent with high fractions of organic aerosol.The hygroscopicity parameter, κ, exhibits remarkably little temporal variability: no pronounced diurnal cycles, only weak seasonal trends, and few short-term variations during long-range transport events. In contrast, the CCN number concentrations exhibit a pronounced seasonal cycle, tracking the pollution-related seasonality in total aerosol concentration. We find that the variability in the CCN concentrations in the central Amazon is mostly driven by aerosol particle number concentration and size distribution, while variations in aerosol hygroscopicity and chemical composition matter only during a few episodes.For modeling purposes, we compare different approaches of predicting CCN number concentration and present a novel parametrization, which allows accurate CCN predictions based on a small set of input data.

  18. Effects of nitrogen deposition and climate change on nitrogen runoff at Norwegian boreal forest catchments: the MERLIN model applied to Risdalsheia (RAIN and CLIMEX projects

    Directory of Open Access Journals (Sweden)

    R. F. Wright

    1998-01-01

    Full Text Available The catchment scale-experiments of the RAIN and CLIMEX projects conducted on boreal forest ecosystems at Risdalsheia, southernmost Norway, provide a unique set of data on the flux of nitrogen (N in runoff following changes in N deposition, carbon dioxide (CO2 level and temperature. MERLIN (Model of Ecosystem Retention and Loss of Inorganic Nitrogen, a recently-developed model that focuses on N leaching, provides a means by which these data can be placed into a quantitative framework. The features of the N flux in runoff at Risdalsheia to be explained include (1 leaching of about 30-50 mmol m-2 yr-1 (30-40% of N deposition during the period 1985-1997 at reference catchments, (2 rapid and dramatic reduction in N leaching following experimental reduction in N deposition in 1985 at KIM catchment, (3 increased flux of about 5 mmol m-2 yr-1 following onset of 3-5°C warming and increased CO2 in 1995 at KIM catchment, and (4 increased flux of about 12 mmol m-2 yr-1 following 3-5°C warming of soil in 1995 at EGIL catchment. One set of calibrated model parameters is sufficient to simulate the changes in N runoff at both experimental catchments for both of the manipulations. The model support the conceptual picture of the soil as the major sink for N inputs from deposition with N accumulating in both the forest floor (labile organic matter LOM and the bulk soil (refractory organic matter ROM. As the molar carbon/nitrogen (C/N ratio of LOM decreases to below 23, progressively less N is immobilised and more goes to runoff. The model also supports the conceptual picture of increased rate of decomposition of old soil organic matter in response to higher temperature. An increase of 5% is sufficient to produce the 5-12 mmol m-2 yr-1 increase in N flux in runoff observed at the 2 experimental catchments. The MERLIN simulations are consistent with measurements of increase in net mineralisation rates (per catchment area by 70 mmol m-2 yr-1 and N contents in

  19. Influence of persistent monodominance on functional diversity and functional community assembly in African tropical forests.

    Science.gov (United States)

    Kearsley, Elizabeth; Verbeeck, Hans; Hufkens, Koen; Beeckman, Hans; Steppe, Kathy; Boeckx, Pascal; Huygens, Dries

    2015-04-01

    Lowland tropical rainforest are taxonomically diverse and complex systems, although not all tropical communities are equally diverse. Naturally occuring monodominant patches of Gilbertiodendron dewevrei are commonly found across Central Africa alongside higher diversity forests. Nevertheless, a low taxonomical diversity does not necessarily indicate an equivalently low functional diverse system. We investigate the functional diversity and functional community assembly of mixed and monodominant tropical forests in a central region of the Congo Basin in D. R. Congo using 15 leaf and wood traits covering 95% of all species within each community. This unique dataset allows us to investigate differences in functional diversity and ecosystem functioning between mixed and monodominant forest types. Functional richness, functional divergence and functional evenness are three functional diversity measures providing different aspects of functional diversity. The largest difference between the two forest types was found for functional richness, with a lower functional richness in the monodominant forest indicating a higher amount of niche space filled in the mixed forest. The mixed forest also had a higher species richness and Simpson diversity index, indicating that the higher species richness increases the functional niche space. Subsequently, we identified whole community trait shifts within the monodominant forest compared to the mixed forest. The dominance of Gilbertiodendron dewevrei, for which a distinct niche is found for most traits, presented a significant influence on the entire (trait) community expressing fundamental differences in ecosystem functioning. More detailed investigation of species unique within the monodominant forest and species occurring in both forest types provide more insight into the influence of Gilbertiodendron dewevrei. Both the unique and the shared species showed significant shifts in leaf nutrients, specific leaf area and water use

  20. Fine-scale genetic structure and cryptic associations reveal evidence of kin-based sociality in the African forest elephant.

    Directory of Open Access Journals (Sweden)

    Stephanie G Schuttler

    Full Text Available Spatial patterns of relatedness within animal populations are important in the evolution of mating and social systems, and have the potential to reveal information on species that are difficult to observe in the wild. This study examines the fine-scale genetic structure and connectivity of groups within African forest elephants, Loxodonta cyclotis, which are often difficult to observe due to forest habitat. We tested the hypothesis that genetic similarity will decline with increasing geographic distance, as we expect kin to be in closer proximity, using spatial autocorrelation analyses and Tau K(r tests. Associations between individuals were investigated through a non-invasive genetic capture-recapture approach using network models, and were predicted to be more extensive than the small groups found in observational studies, similar to fission-fusion sociality found in African savanna (Loxodonta africana and Asian (Elephas maximus species. Dung samples were collected in Lopé National Park, Gabon in 2008 and 2010 and genotyped at 10 microsatellite loci, genetically sexed, and sequenced at the mitochondrial DNA control region. We conducted analyses on samples collected at three different temporal scales: a day, within six-day sampling sessions, and within each year. Spatial autocorrelation and Tau K(r tests revealed genetic structure, but results were weak and inconsistent between sampling sessions. Positive spatial autocorrelation was found in distance classes of 0-5 km, and was strongest for the single day session. Despite weak genetic structure, individuals within groups were significantly more related to each other than to individuals between groups. Social networks revealed some components to have large, extensive groups of up to 22 individuals, and most groups were composed of individuals of the same matriline. Although fine-scale population genetic structure was weak, forest elephants are typically found in groups consisting of kin and

  1. Fine-scale genetic structure and cryptic associations reveal evidence of kin-based sociality in the African forest elephant.

    Science.gov (United States)

    Schuttler, Stephanie G; Philbrick, Jessica A; Jeffery, Kathryn J; Eggert, Lori S

    2014-01-01

    Spatial patterns of relatedness within animal populations are important in the evolution of mating and social systems, and have the potential to reveal information on species that are difficult to observe in the wild. This study examines the fine-scale genetic structure and connectivity of groups within African forest elephants, Loxodonta cyclotis, which are often difficult to observe due to forest habitat. We tested the hypothesis that genetic similarity will decline with increasing geographic distance, as we expect kin to be in closer proximity, using spatial autocorrelation analyses and Tau K(r) tests. Associations between individuals were investigated through a non-invasive genetic capture-recapture approach using network models, and were predicted to be more extensive than the small groups found in observational studies, similar to fission-fusion sociality found in African savanna (Loxodonta africana) and Asian (Elephas maximus) species. Dung samples were collected in Lopé National Park, Gabon in 2008 and 2010 and genotyped at 10 microsatellite loci, genetically sexed, and sequenced at the mitochondrial DNA control region. We conducted analyses on samples collected at three different temporal scales: a day, within six-day sampling sessions, and within each year. Spatial autocorrelation and Tau K(r) tests revealed genetic structure, but results were weak and inconsistent between sampling sessions. Positive spatial autocorrelation was found in distance classes of 0-5 km, and was strongest for the single day session. Despite weak genetic structure, individuals within groups were significantly more related to each other than to individuals between groups. Social networks revealed some components to have large, extensive groups of up to 22 individuals, and most groups were composed of individuals of the same matriline. Although fine-scale population genetic structure was weak, forest elephants are typically found in groups consisting of kin and based on matrilines

  2. The Wonder of Rain Forest Based on Modern Technology——Masoala Hall of Rain Forest in Zurich Zoo%现代科技营造的热带雨林奇观——苏黎世动物园的马苏可立热带雨林馆

    Institute of Scientific and Technical Information of China (English)

    李雱

    2011-01-01

    马苏阿拉热带雨林馆是一项大胆创意的原始森林和濒危动物保护的景观项目,是苏黎世动物园和它在拥有着丰富的热带雨林资源但正受到各种威胁的马达加斯加岛自然保护项目之间的直接联系.这个项目的理念是为了从心灵深处激发公众对自然保护的敏感性,让更多人有直观的保护濒危动植物的切身感受和理念,从而也会更直接地参与到切实的贡献上.各种先进技术结合而成的技术系统营造并维系着这一马达加斯加野生热带雨林的仿真环境,并演示了动(植)物同展示和经营的一种全新模式.%Masoala Hall of Rain Forest is a bold and creative landscape project which aims at the protection of rain forests and endangered animals. It represents a direct link between the Zurich Zoo and its nature conservation project on the island of Madagascar exposed to all kinds of dangers. The concept of this project is to stimulate the public's sensitivity to nature conservation, as such to make more people have an intuitive feeling and idea of immediate protection of endangered species, so that they will be more directly involved on a practical contribution. A technical system which combines a few advanced technologies builds and sustains the simulation of wild tropical rainforest environment of Madagascar in Africa, which demonstrates a brand-new mode of exhibition and operation of zoo and botanical garden.

  3. Vegetation recovery dynamics of tropical lowland rain forest in Bawangling of Hainan Island,South China%海南岛霸王岭热带低地雨林植被恢复动态

    Institute of Scientific and Technical Information of China (English)

    丁易; 臧润国

    2011-01-01

    In Chinese botanical literature, the term "tropical monsoon forest" is explained and used inconsistently and is often confused with tropical rain forest. My objective is to clarify differences between the two forests. Schimper defined tropical monsoon forest as being more or less leafless during the dry season and considered it a transitional vegetation type between tropical rain forest and savanna in terms of physiognomy and distribution. I compared tropical monsoon forest and rain forest in physiognomy, floristic composition and geographical elements to describe and characterize the monsoon forest in Yunnan, China. The tropical monsoon forest in Yunnan occurs mainly on river banks and in basins of several large rivers below 1 000 m altitude. The forest has one or two tree layers, and trees of at least the top layer are deciduous in the dry season. In life forms, the forest is rich in hemicryptophytes and relatively rich in geophytes and therophytes, but less rich in woody lianas and almost lacks megaphanerophytes and chamaephytes compared to tropical rain forest. In leaf size and form, the forest has more microphyllous leaves and compound leaves (24% and 44% of tree species, respectively) than tropical rain forest.In terms of floristic elements, the forest has a greater percentage of species of pantropic distribution (30% of the genera) and tropical Asia and tropical Africa disjunct distribution than tropical rain forest. Thus, the tropical monsoon forest in Yunnan has more diverse geographical elements in its flora and a complicated evolution history.%热带次生林具有重要的物种保育和固碳功能,然而高强度的干扰会导致次生林早期出现类似季雨林的阶段,因而群落恢复速度和方向是当前热带生态学研究中最为关注的议题之一.该文以海南岛在刀耕火种弃耕地形成的不同演替阶段的次生林为研究对象,比较森林不同恢复时间(12年、25年、55年)群落中的不同年龄(幼

  4. Long tree-ring chronologies provide evidence of recent tree growth decrease in a Central African tropical forest.

    Science.gov (United States)

    Battipaglia, Giovanna; Zalloni, Enrica; Castaldi, Simona; Marzaioli, Fabio; Cazzolla-Gatti, Roberto; Lasserre, Bruno; Tognetti, Roberto; Marchetti, Marco; Valentini, Riccardo

    2015-01-01

    It is still unclear whether the exponential rise of atmospheric CO2 concentration has produced a fertilization effect on tropical forests, thus incrementing their growth rate, in the last two centuries. As many factors affect tree growth patterns, short -term studies might be influenced by the confounding effect of several interacting environmental variables on plant growth. Long-term analyses of tree growth can elucidate long-term trends of plant growth response to dominant drivers. The study of annual rings, applied to long tree-ring chronologies in tropical forest trees enables such analysis. Long-term tree-ring chronologies of three widespread African species were measured in Central Africa to analyze the growth of trees over the last two centuries. Growth trends were correlated to changes in global atmospheric CO2 concentration and local variations in the main climatic drivers, temperature and rainfall. Our results provided no evidence for a fertilization effect of CO2 on tree growth. On the contrary, an overall growth decline was observed for all three species in the last century, which appears to be significantly correlated to the increase in local temperature. These findings provide additional support to the global observations of a slowing down of C sequestration in the trunks of forest trees in recent decades. Data indicate that the CO2 increase alone has not been sufficient to obtain a tree growth increase in tropical trees. The effect of other changing environmental factors, like temperature, may have overridden the fertilization effect of CO2.

  5. Using genetic profiles of African forest elephants to infer population structure, movements, and habitat use in a conservation and development landscape in Gabon

    NARCIS (Netherlands)

    Eggert, L. S.; Buij, R.; Lee, M. E.; Campbell, P.; Dallmeier, F.; Fleischer, R. C.; Alonso, A.; Maldonado, J. E.

    2014-01-01

    Conservation of wide-ranging species, such as the African forest elephant (Loxodonta cyclotis), depends on fully protected areas and multiple-use areas (MUA) that provide habitat connectivity. In the Gamba Complex of Protected Areas in Gabon, which includes 2 national parks separated by a MUA contai

  6. using genetic profiles of african forest elephants to infer population structure, movements, and habitat use in a conservation and development landscape in gabon

    NARCIS (Netherlands)

    Eggert, L.S.; Buij, R.; Lee, M.E.; Campbell, P.; Dallmeier, F.; Fleischer, R.C.; Alonso, A.; Maldonado, J.

    2014-01-01

    Conservation of wide-ranging species, such as the African forest elephant (Loxodonta cyclotis), depends on fully protected areas and multiple-use areas (MUA) that provide habitat connectivity. In the Gamba Complex of Protected Areas in Gabon, which includes 2 national parks separated by a MUA contai

  7. 海南尖峰岭热带原始雨林土壤中的暗色丝孢菌研究Ⅰ%Dematiaceous hyphomycetes from soil in tropical primordial rain forest of Jianfengling, Hainan Province of China Ⅰ

    Institute of Scientific and Technical Information of China (English)

    张悦丽; 张天宇; 王洪凤

    2008-01-01

    A total of 66 isolates of soil dematiaceous hyphomycetes belonging to 28 species in 22 genera was found from 22 soil samples in tropical primordial rain forest of Jianfengling in Hainan Island. Among them, the genera Beltraniopsis, Domingoella and Phaeoisaria are recorded for the first timein China, while Acrophialophora fusispora, Beltraniopsis esenbeckiae, Domingoella asterinarum, Phaeoisaria clematidis and Stachybotrys nephrospora are new record species to China. Descriptions and illustrations are given based on Chinese isolates. Dried cultures and living cultures studied have been deposited in Herbarium of Shandong Agricultural University: Plant Pathology (HSAUP).

  8. Multi-decadal carbon and water relations of African tropical humid forests: a tree-ring stable isotope analysis

    Science.gov (United States)

    Hufkens, Koen; Helle, Gerd; Beeckman, Hans; de Haulleville, Thales; Kearsley, Elizabeth; Boeckx, Pascal

    2013-04-01

    Little is known about the temporal dynamics of the carbon sequestering capacity and dynamics of African tropical humid forest ecosystems in response to various environmental drivers. This lack of knowledge is mainly due to the absence of ecosystem scale flux measurements of gas exchange. However, tree growth often displays itself as alternating pattern of visible rings due to the seasonally varying growth speed of the vascular cambium. Consequently, analysis of tree growth through tree-ring analysis provides us with insights into past responses of the carbon sequestering capacity of key species to abrupt ecosystem disturbances and, while slower, a changing climate. Not only does the width and density of growth rings reflect annual growth but their isotopic composition of 13C/12C and 18O/16O isotopes also reveal the environmental conditions in which the trees were growing. In particular, stable isotope ratios in tree-rings of carbon are influenced by fractionation through carboxylation during photosynthesis and changes in leaf stomatal conductance. Similarly, fractionation of oxygen isotopes of soil water occurs at the leaf level through evapo-transipiration. As a consequence, 18O/16O (δ18O) values in wood cores will reflect both the signal of the source water as well as that of for example summer humidity. Therefore, both C and O stable isotopes might not only be valuable as proxy data for past climatic conditions but they also serve as an important tool in understanding carbon and water relations within a tropical forest ecosystems. To this end we correlate long term climate records (1961 - present) with tree ring measurement of incremental growth and high resolution analysis of tree-core stable isotope composition(δ13C , δ18O) at a tropical humid forests in the DR Congo. The Yangambi Man And Biosphere (MAB) reserve is located in the north-eastern part of DR Congo, with a distinct tropical rainforest climate. In addition to the tree-core data records and

  9. Predictable waves of sequential forest degradation and biodiversity loss spreading from an African city.

    Science.gov (United States)

    Ahrends, Antje; Burgess, Neil D; Milledge, Simon A H; Bulling, Mark T; Fisher, Brendan; Smart, James C R; Clarke, G Philip; Mhoro, Boniface E; Lewis, Simon L

    2010-08-17

    Tropical forest degradation emits carbon at a rate of approximately 0.5 Pgxy(-1), reduces biodiversity, and facilitates forest clearance. Understanding degradation drivers and patterns is therefore crucial to managing forests to mitigate climate change and reduce biodiversity loss. Putative patterns of degradation affecting forest stocks, carbon, and biodiversity have variously been described previously, but these have not been quantitatively assessed together or tested systematically. Economic theory predicts a systematic allocation of land to its highest use value in response to distance from centers of demand. We tested this theory to see if forest exploitation would expand through time and space as concentric waves, with each wave targeting lower value products. We used forest data along a transect from 10 to 220 km from Dar es Salaam (DES), Tanzania, collected at two points in time (1991 and 2005). Our predictions were confirmed: high-value logging expanded 9 kmxy(-1), and an inner wave of lower value charcoal production 2 kmxy(-1). This resource utilization is shown to reduce the public goods of carbon storage and species richness, which significantly increased with each kilometer from DES [carbon, 0.2 Mgxha(-1); 0.1 species per sample area (0.4 ha)]. Our study suggests that tropical forest degradation can be modeled and predicted, with its attendant loss of some public goods. In sub-Saharan Africa, an area experiencing the highest rate of urban migration worldwide, coupled with a high dependence on forest-based resources, predicting the spatiotemporal patterns of degradation can inform policies designed to extract resources without unsustainably reducing carbon storage and biodiversity.

  10. Effects of harvest of nontimber forest products and ecological differences between sites on the demography of African mahogany.

    Science.gov (United States)

    Gaoue, Orou G; Ticktin, Tamara

    2010-04-01

    The demographic impacts of harvesting nontimber forest products (NTFP) have been increasingly studied because of reports of potentially unsustainable harvest. Nevertheless, our understanding of how plant demographic response to harvest is altered by variation in ecological conditions, which is critical for developing realistic sustainable-use plans, is limited. We built matrix population models to test whether and how variation in ecological conditions affects population responses to harvest. In particular, we examined the effect of bark and foliage harvest on the demography of populations of African mahogany (Khaya senegalensis) in two contrasting ecological regions of Benin, West Africa. K. senegalensis bark and foliage harvest significantly reduced its stochastic population growth rates, but ecological differences between regions had a greater effect on population growth rates than did harvest. The effect of harvest on population growth rates (Deltalambda) was slightly stronger in the moist than in the drier region. Life-table response experiments revealed that the mechanism by which harvesting reduced lambda differed between ecological regions. Lowered stasis (persistence) of larger life stages lead to a reduction in lambda in the drier region, whereas lowered growth of all life stages lowered lambda in moist region. Potential strategies to increase population growth rates should include decreasing the proportion of individuals harvested, promoting harvester-owned plantations of African mahogany, and increasing survival and growth by promoting no-fire zones in gallery forests. Our results show how population responses to harvest of NTFP may be altered by ecological differences across sites and emphasize the importance of monitoring populations over the climatic range in which they occur to develop more realistic recommendations for conservation.

  11. Quantification of litter and nutrients on an Atlantic Rain Forest/ Quantificação de serapilheira e de nutrientes em uma Floresta Ombrófila Densa

    Directory of Open Access Journals (Sweden)

    Rafaelo Balbinot

    2008-08-01

    Full Text Available No matter what kind of forest it is, the litter production represents the first stage of nutrients and energy transfer from the vegetation to the soil, because most of the nutrients absorbed by the plants comes back to the forest ground through the fall of the litter or leaves wash. The aim of this study was to quantify the production of accumulated litter and nutrient contents on three successional stages of Atlantic Rain Forest, Blumenau/SC - Brazil. For the collections of the accumulated litter five rectangular samples units (SU of 10 m x 20 m were used in each successional stage, in a total of 15 SUs. In each SU the collections of material in an aleatory way was made with the aid of a metal frame of 0.25 m x 0.25 m, with five replications per SU every 30 days (75 samples/month, that is to say, 25 samples/successional stage. The average production of accumulated litter in twenty two months in the collected data was, in a decreasing order, stage III (5.28 Mg ha-1 > stage II (5.02 Mg ha-1 > stage I (4.47 Mg ha-1. The total macronutrient contents on accumulated litter of successional stages I and II, in decreasing order were: N > Ca > Mg > K > S > P, and on stage III: N > Ca > Mg > S > K > P. The forest presented total content of micronutrients on accumulated litter of three successional stages in the following decreasing order: Fe > Mn > Zn > B > Cu. For the total organic carbon content on accumulated litter, the sequence was: stage II (1.65 Mg ha-1 > stage III (1.50 Mg ha-1 > stage I (1.47 Mg ha-1.Seja qual for o tipo de floresta, a produção de serapilheira representa o primeiro estágio de transferência de nutrientes e energia da vegetação para o solo, pois a maior parte dos nutrientes absorvidos pelas plantas retorna ao piso florestal através da queda de serapilheira ou lavagem foliar. O objetivo desse estudo foi quantificar a produção de serapilheira acumulada e o conteúdo de nutrientes em três estádios sucessionais da Floresta

  12. Human impact on wildlife populations within a protected Central African forest

    NARCIS (Netherlands)

    Blom, A.; Heitkönig, I.M.A.; Prins, H.H.T.; Zalinge, van R.; Mbea, E.

    2004-01-01

    This paper addresses the effect of human activities on the density of large mammals in the Dzanga-Ndoki National Park and the adjacent Dzanga-Sangha Reserve in the Central African Republic. Between six and eight 20 km long permanent transects were walked on a monthly basis from January 1997 to Augus

  13. Vertical profiles of ozone between 0 and 400 meters in and above the African equatorial forest

    Science.gov (United States)

    Cros, B.; Fontan, J.; Minga, A.; Helas, G.; Nganga, D.; Delmas, R.; Chapuis, A.; Benech, B.; Druilhet, A.; Andreae, M. O.

    1992-08-01

    Results are presented of measurements of ozone concentrations in the northern Congo, near Impfondo, as part of the DECAFE experiment in February 1988, during the dry season. The measurements were carried out simultaneously at ground level in a large clearing, inside the forest between 0 and 30 m, and above the forest with a captive balloon flying up to 400 m. The results presented are compared with the data obtained in the Mayombe forest in southern Congo, near Dimonika, in June 1988, during the dry season. For both northern and southern forested areas the ozone concentrations measured at ground level in a large clearing exhibit daily variations with maxima in the afternoon ranging between 10 and 30 parts per billion by volume (ppbv) and minima at the end of the night between 4 and 15 ppbv. The characteristics of each surface ozone cycle are analyzed. Inside the forest, ozone concentrations are found very low near the ground, and rarely exceed 15 ppbv above the canopy. The relationships among the vertical profiles of ozone, temperature, and water vapor are discussed.

  14. Long tree-ring chronologies provide evidence of recent tree growth decrease in a Central African tropical forest.

    Directory of Open Access Journals (Sweden)

    Giovanna Battipaglia

    Full Text Available It is still unclear whether the exponential rise of atmospheric CO2 concentration has produced a fertilization effect on tropical forests, thus incrementing their growth rate, in the last two centuries. As many factors affect tree growth patterns, short -term studies might be influenced by the confounding effect of several interacting environmental variables on plant growth. Long-term analyses of tree growth can elucidate long-term trends of plant growth response to dominant drivers. The study of annual rings, applied to long tree-ring chronologies in tropical forest trees enables such analysis. Long-term tree-ring chronologies of three widespread African species were measured in Central Africa to analyze the growth of trees over the last two centuries. Growth trends were correlated to changes in global atmospheric CO2 concentration and local variations in the main climatic drivers, temperature and rainfall. Our results provided no evidence for a fertilization effect of CO2 on tree growth. On the contrary, an overall growth decline was observed for all three species in the last century, which appears to be significantly correlated to the increase in local temperature. These findings provide additional support to the global observations of a slowing down of C sequestration in the trunks of forest trees in recent decades. Data indicate that the CO2 increase alone has not been sufficient to obtain a tree growth increase in tropical trees. The effect of other changing environmental factors, like temperature, may have overridden the fertilization effect of CO2.

  15. High-Resolution Forest Canopy Height Estimation in an African Blue Carbon Ecosystem

    Science.gov (United States)

    Lagomasino, David; Fatoyinbo, Temilola; Lee, Seung-Kuk; Simard, Marc

    2015-01-01

    Mangrove forests are one of the most productive and carbon dense ecosystems that are only found at tidally inundated coastal areas. Forest canopy height is an important measure for modeling carbon and biomass dynamics, as well as land cover change. By taking advantage of the flat terrain and dense canopy cover, the present study derived digital surface models (DSMs) using stereophotogrammetric techniques on high-resolution spaceborne imagery (HRSI) for southern Mozambique. A mean-weighted ground surface elevation factor was subtracted from the HRSI DSM to accurately estimate the canopy height in mangrove forests in southern Mozambique. The mean and H100 tree height measured in both the field and with the digital canopy model provided the most accurate results with a vertical error of 1.18-1.84 m, respectively. Distinct patterns were identified in the HRSI canopy height map that could not be discerned from coarse shuttle radar topography mission canopy maps even though the mode and distribution of canopy heights were similar over the same area. Through further investigation, HRSI DSMs have the potential of providing a new type of three-dimensional dataset that could serve as calibration/validation data for other DSMs generated from spaceborne datasets with much larger global coverage. HSRI DSMs could be used in lieu of Lidar acquisitions for canopy height and forest biomass estimation, and be combined with passive optical data to improve land cover classifications.

  16. Foliar trait contrasts between African forest and savanna trees: Genetic versus environmental effects

    NARCIS (Netherlands)

    Schrodt, F.; Domingues, T.F.; Feldpausch, T.; Saiz, G.; Quesada, C.A.; Schwarz, K.M.; Veenendaal, E.

    2015-01-01

    Variations in leaf mass per unit area (Ma) and foliar concentrations of N, P, C, K, Mg and Ca were determined for 365 trees growing in 23 plots along a precipitation gradient ranging from 0.29 m a-1 to 1.62 m a-1. The transect extended from just south to the Sahara Desert in Mali to the forest-savan

  17. Sediment biogeochemistry in an East African mangrove forest (Gazi Bay, Kenya)

    NARCIS (Netherlands)

    Middelburg, J.J.; Nieuwenhuize, J.; Slim, F.J.; Ohowa, B.

    1996-01-01

    The biogeochemistry of mangrove sediments was investigated in several mangrove forest communities in Gazi Bay, a coastal lagoon in Kenya, Africa. Carbon dioxide fluxes, sediment median grain sizes, sedimentary organic carbon, nitrogen and phosphorus contents and pore-water characteristics (ammonium,

  18. Changes in land cover and carbon emissions to 2050 from African tropical forests using policy scenarios

    Science.gov (United States)

    Laporte, N.; Galford, G. L.; Soares Filho, B. S.

    2011-12-01

    Africa has the second largest block of rainforest in the world, next to the Amazon basin, with the majority of the carbon being stored in the dense humid forests of the Democratic Republic of the Congo (DRC). Historically, political instability in the DRC kept development and deforestation low, with primary forest uses being extensive logging and small scale agriculture. In the last decade, political stability has opened the country to foreign investment in forested areas, largely for industrial-scale oil palm plantations and more recently to rice production. The DRC ranks worst on the IFPRI global hunger index, scoring "extremely serious" based on the proportion of undernourished population, prevalence of underweight in children under 5 and the mortality rates of children under 5. In fact, DRC saw its hunger score increase (worsen) from 1990 to 2010, with a 66% gain compared to the other 8 worsening countries increasing only 21% or less. This is a critical time for policy in the DRC, where business-as-usual (relatively low deforestation rates) is unlikely to continue given today's relative political stability and economic stabilization compared to the 1990s. The country must examine options for forest conservation in balance with foreign investment for use of forest resources, national development of rural livelihoods and domestic production of food. Here we present deforestation trajectories simulated through the year 2050 under a set of scenarios. The scenarios consider the relative carbon emissions from business-as-usual (no new policy), conservation (policy favoring protection and enforcement for forest areas), and a food security scenario (favoring clearing for industrial agriculture, extractive timber resources and development of new agricultural areas). Carbon emissions for each scenario are estimated with a coupled bookkeeping model. These scenarios are not predictive of the future, rather, they are meant to provide an understanding of the outcomes of

  19. 喀斯特季节性雨林蚬木种群结构和数量动态%Age structure and quantitative dynamics of Excentrodendron hsienmu population in a karst seasonal rain forest in South China

    Institute of Scientific and Technical Information of China (English)

    向悟生; 王斌; 丁涛; 黄俞淞; 农重刚; 刘晟源; 李先琨

    2013-01-01

    蚬木是喀斯特季节性雨林的特征种.为了了解蚬木种群的结构和生存状态,根据一个15 hm2固定样地的调查数据,采用数量分析方法研究了蚬木种群的年龄结构和数量动态特征.结果表明,蚬木种群的幼龄个体数量很多,年龄结构呈倒-J型;存活曲线可以同时被DeevyⅡ和DeevyⅢ型曲线拟合,但更倾向于DeevyⅡ型曲线;特定时间生命表分析结果表明,种群的死亡率在年龄级0~9a、60~69 a出现明显的峰值;生存分析结果显示,蚬木种群生存状态具有前期波动、中期稳定、后期衰退的特点;谱分析结果表明,蚬木种群动态未发现有明显的大周期波动,但存在一个长度为lla左右的小周期波动.综上研究结果,研究区内的蚬木种群为增长型种群结构;在不同发育阶段,蚬木种群的生存状态存在波动,在种群发育的前期和后期生存状态不稳定;蚬木种群的年龄结构和数量动态可能受本身生物学特性、负密度制约效应、喀斯特地质性干旱等因素的影响较大.%Excentrodendron hsienmu is a characteristic species in karst seasonal rain forest, and thus, to study the age structure and survival status of E. hsienmu population can provide insight into the succession process and status of karst seasonal rain forest. Based on the investigation data from a 15 hm2 plot in a karst seasonal rain forest at Nonggang of South China, and by using quantitative analysis method, this paper studied the age structure and quantitative dynamics of E. hsienmu population in the forest. In the forest, E. hsienmu population was characterized by the abundance of young individuals, and the age structure of the population was in an inverse-J shape. The survival curve of the population could be described by the Deevy Ⅱ curve and Deevy Ⅲ curve, but more appropriately by Deevy Ⅱ curve, which implied that E. hsienmu reproduced a large number of offspring to maintain its

  20. Rain Barrels in Utah

    OpenAIRE

    Greene, Brian; Mesner, Nancy; Brain, Roslynn

    2015-01-01

    Rain barrels are an easy way to conserve rain water and help protect our environment. This fact sheet tells how to find out about the current regulations in Utah and how to build a rain barrel for your own home.

  1. Abelhas africanizadas Apis mellifera scutellata Lepeletier, 1836 (Hymenoptera: Apidae: Apinae exploram recursos na floresta amazônica? Do Africanized honeybees explore resources in the amazonian forest?

    Directory of Open Access Journals (Sweden)

    Marcio Luiz de Oliveira

    2005-09-01

    quickly and expand throughout nearly of the Americas. Moreover, to date there is much controversy about the probable impact of these bees, called Africanized honey bees, on native bees. In the Americas, Africanized honeybees are limited to regions of low altitude and cool winters, and in Brazil they occur principally in urban areas, and open or disturbed vegetation, not occurring in the interior of dense forest such as the Amazon Forest. We offered various kinds of bait in the interior of continuous forest, and in forest fragments to verify if Africanized honeybees would be capable of penetrate in it. No Africanized honeybee workers visited any baits in continuous forest or in forest fragments, but they did so in deforested/open areas. This result indicates that there is no possibility of source competition between Africanized and native bees within Amazon forest, and also indicates that large-scale beekeeping is unlikely to succeed in this region, because forest is not explored by Africanized bees.

  2. Predictable waves of sequential forest degradation and biodiversity loss spreading from an African city

    DEFF Research Database (Denmark)

    Ahrends, A.; Burgess, N.D.; Milledge, S.A.H.

    2010-01-01

    ). Our predictions were confirmed: high-value logging expanded 9 km.y(-1), and an inner wave of lower value charcoal production 2 km.y(-1). This resource utilization is shown to reduce the public goods of carbon storage and species richness, which significantly increased with each kilometer from DES...... [carbon, 0.2 Mg.ha(-1); 0.1 species per sample area (0.4 ha)]. Our study suggests that tropical forest degradation can be modeled and predicted, with its attendant loss of some public goods. In sub-Saharan Africa, an area experiencing the highest rate of urban migration worldwide, coupled with a high...... dependence on forest based resources, predicting the spatiotemporal patterns of degradation can inform policies designed to extract resources without unsustainably reducing carbon storage and biodiversity...

  3. 弄岗自然保护区石灰岩山地季雨林的群落分类及分布%Plant community classification and distribution of limestone hill seasonal rain forest in Longgang Nature Reserve

    Institute of Scientific and Technical Information of China (English)

    胡春园; 汪正祥; 雷耘

    2012-01-01

    Researches on plant community classification and the plant community-environmental relationship are of great importance on the ecosystem protection and management. In this studyi plant communities of limestone hill seasonal rain forests were classification and the habitat of the plant community were analyzed in Longgang. Nature Reserve by phytosociological method. Results showed that the vegetation of limestone hill seasonal rain forest in Longgang Nature Reserve could divide into two formations, three associations and five communities based on 34 sites. There were Form. Cephalo-mappa sinensis-Excentrodendron tonkinense, Form. Arenga westerhoutii-Deutzianthus tonkinensis; Ass. Cleistanthus petelotii-Laportea violacea, Ass. Baccaurea ramiflora-Trigonostemon fragilis, Ass. Phlogacanthus colaniae-Aglaia lawii; Comm. Streblus tonkinensis-Champereia manillana var. longistaminea, Comm. Guihaia argyrata-Dracae-na cochinchinensis, Comm. Ardisia affinis-Archidendron eberhardtii, Comm. Cinnamo-mum wilsonii, Comm. Sinosideroxylon pedunculatum-Pistacia weinmannifolia. . There-suits of this study provided some initial information for the protected and management of the limestone hill seasonal rain forest.%采用植物社会学植被研究方法,对弄岗自然保护区石灰岩山地季雨林的群落进行分类.根据34个调查样方资料,划分出2个群系、3个群丛及5个群落.即:群系:肥牛树-蚬木群系、桄榔-东京桐群系;群丛:假肥牛树-葡萄叶艾麻群丛、木奶果-黄花三宝木群丛、广西火焰花-四瓣米仔兰群丛;群落:米扬噎-茎花山柚群落、石山棕-剑叶龙血树群落、罗伞树-大棋子豆群落、川桂群落、毛叶铁榄-清香木群落.

  4. Spatiotemporal dynamics of seed rain in natural forest of Betula alnoides in Jingxi County,Guangxi, China%广西靖西西南桦天然林种子雨的时空动态

    Institute of Scientific and Technical Information of China (English)

    郭俊杰; 赵志刚; 欧景莉; 沙二; 林开勤; 曾杰; 徐大平

    2012-01-01

    Aims Our objective was to study spatiotemporal dynamics of seed dispersal of Betula alnoides and analyze its correlation with wind speed and wind direction at community and individual levels. Methods Seed dispersal was investigated for a natural forest and an isolated tree of B. alnoides. We set seven sample lines 100 to 355 m long in or around the natural forest. One seed trap was placed every 5 m, and seeds were collected every two days. We set eight sample lines (east, southeast, south, southwest, west, northwest, north, northeast) around the isolated tree. Three seed traps were placed every 5 m from 0 to 50 m and every 10 m from 60 to 150 m, and seeds were collected each day. Wind speed and wind directions were measured at two sites. Seed rain density was calculated. Important findings The seed rain lasted 83 and 60 days at the community and individual levels, respectively. The starting, fastigium and subsiding stages of seed dispersal lasted 11,32 and 40 days for the community and 9, 25 and 26 days for the isolated individual. Seeds dispersed at the fastigium stage accounted for 83.1% and 68.7% of all seeds collected at the community and individual levels, respectively. Seed rain density was higher during the day than at night, and the highest seed rain density by day occurred at 12:00-16:00. At the individual level, seed rain density decreased with increasing distance from the maternal tree, and 79.6% of seeds were collected in the area of 0-30 m around the maternal tree. Seed rain density at the community level also decreased with longer distance from the forest edge, and 79.6% of seeds were collected in the area of 0-45 m around the forest edge. The seed rain density was significantly different among directions (p < 0.01), which was affected by wind direction. Seed rain density was also positively affected by wind speed (p < 0.05).%以一片西南桦(Betula alnoides)天然林和一个西南桦独立单株为研究对象,通过收集散种期内与林分或

  5. Refuge Begonias. Taxonomy, phylogeny and historical biogeography of Begonia sect. Loasibegonia and sect. Scutobegonia in relation to glacial rain forest refuges in Africa.

    NARCIS (Netherlands)

    Sosef, M.S.M.

    1994-01-01

    Begonia is a genus of + 1000 species and is represented in all tropical areas. In Wageningen, under the guidance of dr J.J.F.E. de Wilde, the continental African begonias are being studied. Continental Africa has some 120 species, divided over 10 sections, and compared with the amount of spe

  6. Anticancer activity of five forest crops used in African folklore: antiproliferative and pro-apoptotic effects.

    Science.gov (United States)

    Erharuyi, Osayemwenre; Engel-Lutz, Nadja; Ahomafor, Joy; Imieje, Vincent; Falodun, Abiodun; Nebe, Babara; Langer, Peter

    2014-02-26

    Acalypha wilkesiana, Caesalpinia bonduc, Jatropha multifida, Momordica charantia and Picralima nitida used in African folklore for treating cancer were investigated. All extracts except J. multifida resulted in no significant alteration in cell cycle distribution and apoptosis in MCF-7 and BT-20. The J. multifilda (JMR-Ch) caused cell cycle arrest at G1 checkpoint and apoptosis in MCF-7. Slight changes in the integrin expression of MCF-7 after treatment with 1 and 10 μg/mL of JMR-Ch were observed. Fluorescence-activated confocal microscopy shows changes in cell morphology and β1 integrin localisation within MCF-7 cells after exposure to 10 and 25 μg/mL of JMR-Ch. JMR-Ch (1 μg/mL) treatment resulted in time-dependent decrease in cell acidification and respiration in MCF-7 cells and a time-dependent decrease in BT-20 cell respiration, while in MCF-10A, there was an enhancement of acidification. These results revealed the probable application of JMR-Ch in cancer therapy.

  7. Effects of simulated acid rain on germination, seedling growth and oxidative metabolism of recalcitrant-seeded Trichilia dregeana grown in its natural seed bank.

    Science.gov (United States)

    Ramlall, Chandika; Varghese, Boby; Ramdhani, Syd; Pammenter, Norman W; Bhatt, Arvind; Berjak, Patricia; Sershen

    2015-01-01

    Increased air pollution in a number of developing African countries, together with the reports of vegetation damage typically associated with acid precipitation in commercial forests in South Africa, has raised concerns over the potential impacts of acid rain on natural vegetation in these countries. Recalcitrant (i.e. desiccation sensitive) seeds of many indigenous African species, e.g. must germinate shortly after shedding and hence, may not be able to avoid exposure to acid rain in polluted areas. This study investigated the effects of simulated acid rain (rainwater with pH adjusted to pH 3.0 and 4.5 with 70:30, H2 SO4 :HNO3 ) on germination, seedling growth and oxidative metabolism in a recalcitrant-seeded African tree species Trichilia dregeana Sond., growing in its natural seed bank. The results suggest that acid rain did not compromise T. dregeana seed germination and seedling establishment significantly, relative to the control (non-acidified rainwater). However, pH 3.0 treated seedlings exhibited signs of stress typically associated with acid rain: leaf tip necrosis, abnormal bilobed leaf tips, leaf necrotic spots and chlorosis, reduced leaf chlorophyll concentration, increased stomatal density and indications of oxidative stress. This may explain why total and root biomass of pH 3.0 treated seedlings were significantly lower than the control. Acid rain also induced changes in the species composition and relative abundance of the different life forms emerging from T. dregeana's natural seed bank and in this way could indirectly impact on T. dregeana seedling establishment success.

  8. Did Neoliberalizing West African Forests Produce a New Niche for Ebola?

    Science.gov (United States)

    Wallace, Robert G; Kock, Richard; Bergmann, Luke; Gilbert, Marius; Hogerwerf, Lenny; Pittiglio, Claudia; Mattioli, Raffaele; Wallace, Rodrick

    2016-01-01

    A recent study introduced a vaccine that controls Ebola Makona, the Zaire ebolavirus variant that has infected 28,000 people in West Africa. We propose that even such successful advances are insufficient for many emergent diseases. We review work hypothesizing that Makona, phenotypically similar to much smaller outbreaks, emerged out of shifts in land use brought about by neoliberal economics. The epidemiological consequences demand a new science that explicitly addresses the foundational processes underlying multispecies health, including the deep-time histories, cultural infrastructure, and global economic geographies driving disease emergence. The approach, for instance, reverses the standard public health practice of segregating emergency responses and the structural context from which outbreaks originate. In Ebola's case, regional neoliberalism may affix the stochastic "friction" of ecological relationships imposed by the forest across populations, which, when above a threshold, keeps the virus from lining up transmission above replacement. Export-led logging, mining, and intensive agriculture may depress such functional noise, permitting novel spillovers larger forces of infection. Mature outbreaks, meanwhile, can continue to circulate even in the face of efficient vaccines. More research on these integral explanations is required, but the narrow albeit welcome success of the vaccine may be used to limit support of such a program.

  9. Challenges and difficulties in service to legal requirements applicable to a pipeline works at the Amazon rain forest, Brazil; Os desafios e dificuldades no atendimento aos requisitos legais aplicaveis a uma obra na Amazonia

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, Wanderleia I.P. de [Universidade do Estado do Amazonas (UEA), Manaus, AM (Brazil); Freitas, Jaluza G.M.R. de; Teixeira, Ivan J.L. [Concremat Engenharia e Tecnologia, Rio de Janeiro, RJ (Brazil)

    2008-07-01

    This work brings together the difficulties and results generated in response to Brazilian Environmental Law applicable to a work of pipelines in the Amazon. We are a country that has the most extensive and rich environmental legislation in the world, and Engineering at PETROBRAS, through the Implementation of Enterprise for the North, responsible for the deployment of this pipeline, has ISO 14001:2004 certification, taking as the minimum requirement attending the applicable legal requirements, and serve them in if there are difficulties elsewhere in the country, here in the Amazon it is increased meet the logistical difficulties, the distances from major centres, the needs of technology, information and access to basic resources. This article discusses topics such as: transport of hazardous waste in an environmentally safe way in one of the largest rivers in the world, installing devices sewage treatment in regional boats, and teach the riparian preserve the historic and archaeological findings, these are just examples found. We know that all eyes of the world is impressive return to the Amazon rain forest, and that cross, or rather 'rip' their 383 km of primary forest, virgin land, almost untouched even by the people native of the region, in itself constitutes a great challenge. (author)

  10. A modelling approach for simulation of water and carbon dioxide exchange between multi-species tropical rain forest and the atmosphere

    DEFF Research Database (Denmark)

    Olchev, A.; Ibrom, Andreas; Ross, T.;

    2008-01-01

    of the physical and biological processes on the leaf, tree (plant) and stand levels that allows to apply this model for prediction of atmospheric fluxes for the different vegetation types from grasslands and agricultural crops to vertically structured mono-specific and mixed forest stands represented by one.......g. height, crown shape, stem diameter, root depth) and biological properties (e.g. leaf stomatal conductance, photosynthesis and respiration rates, etc.). Mixfor-SVAT assumes that trees of the different species are evenly distributed over some homogeneous ground surface area......, precipitation rate and global radiation) at some height above a plant canopy within the atmospheric surface layer. For simulation of exchange processes within a multi-specific forest stand Mixfor-SVAT uses both averaged and species specific biophysical parameters of the trees describing their structure (e...

  11. 松华坝水源区森林微集水区降雨与径流过程分析%Analysis of Rainfall and Runoff Process in Forest's Micro Rain Collection Area in Songhuaba Water Source Area

    Institute of Scientific and Technical Information of China (English)

    武军

    2015-01-01

    Micro rain collection area is basic hydrologic unit in mountainous area ,whose characteristics of rainfall and runoff process can provide important data for the study of hydrologic regularity .The research observes the forest's micro rain collection area in Yizhe valley uninterruptedly .The results show that the rainfall capacity can affect the runoff output directly .On July 19 ,the 24hous'rainfall was 36 .6mm and the runoff output is 105 .57m3 ;the crest value of runoff always lags behind that of rainfall .In the monitoring of rainfall - runoff on July 19 ,the maximum runoff lagged behind the maximum rainfall for 2 hour 50minutes .%微集水区是山区最基本的水文单元,其降雨产流特征研究可以为流域水文的规律研究提供重要的数据支持。针对迤者小流域的森林微集水区进行不间断观测,得出结论:降雨量直接影响微集水区的径流产生量,7月19日24h内降雨量为36.6mm ,降雨性产流105.57m3;径流洪峰一般滞后于降雨量峰值,7月19日降雨—径流监测中,最大产流值滞后最大降雨量值2h50min。

  12. Rain Gauges Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Bartholomew, M. J. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-01-01

    To improve the quantitative description of precipitation processes in climate models, the Atmospheric Radiation Measurement (ARM) Climate Research Facility deployed rain gauges located near disdrometers (DISD and VDIS data streams). This handbook deals specifically with the rain gauges that make the observations for the RAIN data stream. Other precipitation observations are made by the surface meteorology instrument suite (i.e., MET data stream).

  13. Acid Rain Study Guide.

    Science.gov (United States)

    Hunger, Carolyn; And Others

    Acid rain is a complex, worldwide environmental problem. This study guide is intended to aid teachers of grades 4-12 to help their students understand what acid rain is, why it is a problem, and what possible solutions exist. The document contains specific sections on: (1) the various terms used in conjunction with acid rain (such as acid…

  14. The Acid Rain Reader.

    Science.gov (United States)

    Stubbs, Harriett S.; And Others

    A topic which is often not sufficiently dealt with in elementary school textbooks is acid rain. This student text is designed to supplement classroom materials on the topic. Discussed are: (1) "Rain"; (2) "Water Cycle"; (3) "Fossil Fuels"; (4) "Air Pollution"; (5) "Superstacks"; (6) "Acid/Neutral/Bases"; (7) "pH Scale"; (8) "Acid Rain"; (9)…

  15. Effect of a major highway on the spatial and temporal variation in the structure and diversity of the avifauna of a tropical premontane rain forest

    OpenAIRE

    Ávalos, Gerardo; Bermúdez, Esteban

    2016-01-01

    Roads immersed in conservation areas will increase in number, size, and traffic over the next decade, and thus, understanding their effects on forest-dependent wildlife is crucial for improving current management practices and reducing the negative impacts of roads on sensitive species. We examined the influence of route 32 (a.k.a. Guápiles Highway) on temporal and spatial changes in the structure of the avifauna of Braulio Carrillo National Park, Costa Rica, a site crossed by this road along...

  16. Ecological succession of a stretch of Dense Rain Forest in the Lowlands, Carauari, Amazonas, Brazil Sucessão ecológica de um trecho de Floresta Ombrófila Densa de Terras Baixas, Carauari, Amazonas

    Directory of Open Access Journals (Sweden)

    Rosival Barros de Andrade Lima

    2011-09-01

    Full Text Available

    This work was carried out in a stretch of Dense Rain Forest in the lowland county of Carauari, Amazonas, aiming to estimate the species composition of tree layer and classify the species in their ecological groups in order to obtain information about the current situation of the forest fragment, to be the basis for strategies for conservation and preservation as well as the basis for formulating research aimed at the dissemination of knowledge and its application to sustainable production. The forest inventory was conducted in an area of 275 ha, crossed by three transects (822 m, 1,265 m and 2,349 m, totaling 4.436 m. Plots were installed in 20 m x 25 m, 50 m equidistant, merged to the right and left of the line transect, totaling 66 sampling units. All tree individuals trees that had a circumference of 1,30 m above the ground (CAP ≥ 25 cm were identified and measured. There were 3,050 individuals distributed in 133 species, 93 genera and 49 families. It was observed that the species of early succession (pioneer + early secondary were more numerous, showing characteristics of a forest in early successional stage.

     

    doi: 10.4336/2011.pfb.31.67.161

    O presente trabalho foi realizado em um trecho de Floresta Ombrofila Densa de Terras Baixas no Municipio de Carauari, Amazonas, tendo como objetivo estimar a composicao floristica do estrato arboreo e classificar as especies nos respectivos grupos ecologicos, a fim de se obter informacoes sobre a atual situacao do fragmento florestal, para embasar estrategias de conservacao e preservacao, bem como embasar a formulacao de pesquisas que visem a disseminacao do conhecimento e sua aplicacao na producao sustentavel. O inventario florestal foi realizado em uma area de 275 ha, cortada por tres transectos (822 m, 1.265 m e 2.349 m, totalizando 4.436 m. Foram instaladas parcelas de 20 m x 25 m, equidistantes a cada 50 m e intercaladas a direita e a esquerda da linha do

  17. 热带雨林的孢粉垂直分布规律——以海南岛现代孢粉雨为例%MODERN POLLEN RAIN IN HAINAN ISLAND, SOUTHERN CHINA: ALTITUDINAL POLLEN DISTRIBUTION IN THE TROPICAL RAIN FOREST

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    热带地区环境变化对研究全球气候变化显得越来越重要,热带地区的古环境记录,特别是孢粉记录是恢复过去气候的重要方法.东亚热带地区在冰期-间冰期的气候影响下,生态环境主要表现为山地植被带的垂直升降.因此,定量恢复热带地区第四纪植被垂直移动的幅度,以及作为古气候的替代性指标进行数量化转换是热带地区孢粉研究的关键.然而,我国热带地区现代孢粉雨和植被的关系研究程度较低,给热带第四纪孢粉古生态的恢复和对比带来困难.本研究较系统地总结了海南岛从低地平原到五指山1860m的垂直植被带表土的孢粉散布规律,为热带地区孢粉占环境的重建提供了新的基础数据.研究结果表明,孢粉组合的变化与垂直植被带紧密相关,孢粉的多样性随海拔升高而降低,其中针叶类随海拔升高而增加,蕨类孢子则相应减少.在低地和低山h丘陵,孢粉组合显示出人为干扰的影响,如防风林的主要树种木麻黄(Casuarina)、行道树台湾相思(Acacia richii)和人为砍伐后大面积生长的芒箕(Dicranopteris)群落等在一些孢粉谱中特别高.尽管如此,孢粉组合反映的垂直植被带变化仍然是清楚的,海南岛由下至上可划分出5个表上孢粉组合带:-低地人类强烈干扰带(<400 m):Mallotus,Casuarina,Pinus,Myrica,Palmae,Poaceae,Dicranopteris:-低地丘陵地带(400-800 m):Quercus,Castanopsis,Mallotus,Myrica,Platea,Meliaceae和大量孢子(包括Dicranopteris);-山地下带(800-1200 m):Castanopsis,Quercus,Podocarpus,Dacrydium,Cyathea和单缝孢子;-山地上带(1200-1600 m):Dacrydium,Pinus,Altingia,Quercus,Castanopsis;-山顶带(>1600 m):Pinus,Rhododendron,Dacrydium,Symplocos.%Modern pollen rain study was carded out on the samples collected from Hainan Island, tropical China along analtitudinal gradient from 0-1860 m (from lowland rainforests or savannas to Ericaceae and highland pine forest). The

  18. MORTALIDAD Y RECLUTAMIENTO DE ÁRBOLES EN UN BOSQUE PLUVIAL TROPICAL DE CHOCÓ (COLOMBIA MORTALITY AND RECRUITMENT OF TREES IN A TROPICAL RAIN FOREST OF CHOCÓ (COLOMBIA

    Directory of Open Access Journals (Sweden)

    Harley Quinto Mosquera

    2009-06-01

    Full Text Available Se calcularon las tasas de mortalidad y reclutamiento de árboles en una parcela permanente de investigación de un bosque pluvial tropical. El estudio se basó en dos mediciones, una realizada en el año 1998 y la otra en el 2005, en las cuales se midió el diámetro (DAP a todos los árboles con DAP>10 cm y se censaron los individuos muertos y reclutados. Se determinaron los tipos de mortalidad y se calculó el coeficiente de mortalidad, el coeficiente de reclutamiento exponencial, la biomasa aérea (BA y la vida media del bosque. En el primer censo se registraron 709 individuos y en el segundo se encontraron 710. La tasa media anual de mortalidad de árboles fue 1,39% y el coeficiente de mortalidad exponencial fue 1,41%; los tipos de mortalidad más comunes fueron: volcamiento de raíz y muerte en pie. La tasa de reclutamiento anual fue 1,2% y el coeficiente de reclutamiento exponencial registró 1,19%. La vida media estimada de la parcela fue 58,6 años. La BA fue de 237,31 t ha-1 en el año 1998, y en el 2005 fue 259,9 t ha-1. Los individuos reclutados presentaron BA de 5,08 t ha-1, y los muertos de 17,72 t ha-1; el incremento en BA de sobrevivientes fue 30,97 t ha-1 promedio. La similitud en el número de individuos entre mediciones, así como en los demás parámetros evaluados, sugieren un posible equilibrio entre mortalidad y reclutamiento del bosque. Con base en estos resultados, no se puede rechazar la hipótesis de equilibrio dinámico.Rates of mortality and recruitment of trees were calculated in a permanent research plot established in the tropical wet forest. The study was based on two measurements, one was done in 1998 and the other in 2005, in which were measured the diameter (DBH of trees with DBH>10 cm and surveyed dead and recruited trees. We also determined the type of mortality, the mortality and exponential recruitment coefficient, the aboveground biomass (AB and the mean life of the forest. In the first census 709

  19. Chuva de sementes de espécies lenhosas florestais em mosaicos de floresta com Araucária e campos no Sul do Brasil Seed rain of woody species in mosaics of Araucaria forest and grasslands in Southern Brazil

    Directory of Open Access Journals (Sweden)

    Melina Marchesini Grassotti dos Santos

    2011-03-01

    southern Brazil, Araucaria forest forms a mosaic with grassland (Campos and advance of forest over grassland is observed. This study aims to evaluate the pattern of diaspore dispersal of woody plants associated with ecotones between Araucaria forest and grassland and with isolated woody individuals in the grassland matrix. The study was carried out at the Centro de Pesquisas e Conservação da Natureza Pró-Mata PUCRS, in São Francisco de Paula, in grassland vegetation excluded from fire and grazing for 16 years, and which is surrounded by forest. Diaspore dispersal was evaluated for eight months by using collectors positioned in forest-grassland ecotones with different physiognomies and under isolated woody individuals in the grassland matrix. The different types of environment were compared by univariate and multivariate analysis of variance to verify seed-rain patterns. The results indicated that seed dispersal occurs preferentially associated with isolated woody individuals of Araucaria angustifolia and with continuous patches of Baccharis uncinella. We suggest that these habitats would function as extensions of more similar forest conditions within the grassland matrix.

  20. Estrutura do componente arbustivo-arbóreo da floresta atlântica de encosta, Peruíbe, SP Structure of the tree and shrub component of the Atlantic rain forest, Peruíbe, SP

    Directory of Open Access Journals (Sweden)

    Rosemary de Jesus Oliveira

    2001-12-01

    Full Text Available Foi comparada a estrutura do componente arbustivo-arbóreo da floresta pluvial tropical atlântica de encosta, em diferentes classes de tamanho, e discutida a dinâmica de sua regeneração. Para a amostragem da vegetação foram utilizadas parcelas com dimensões que variaram de acordo com a classe de tamanho considerada: Classe I (indivíduos com altura 15,0cm e 1,30m e DAP ou = 5,0cm - dez parcelas de 10x20m. Obteve-se maior diversidade para as classes intermediárias, devido à distribuição mais eqüitativa dos indivíduos entre as espécies, sendo também mais similares floristicamente. A maioria das espécies e dos indivíduos pertenciam às categorias sub-bosque e secundárias tardias-climácicas, em todas as classes de tamanho, sugerindo que a estrutura atual da floresta tem favorecido a regeneração destes grupos.In this study the structure of the sub-montane Atlantic tropical rain forest tree and shrub component in different size classes was compared and their regeneration dynamics was discussed. The plants in each size class were sampled in plots of different size: Class I (individuals 15cm and 1,3m tall and or = 5cm DBH in ten 10x20m plots. The highest diversity was found in intermediate size classes was due to a more even distribution of individuals among species. These classes had also the highest values of quantitative and qualitative species similarity indices. The majority of the species and the individuals were secondary-climax and under-story, suggesting that the present forest structure have favored the regeneration of these plant groups.

  1. Chuva de sementes em Floresta Estacional Semidecidual em Viçosa, MG, Brasil Seed rain in a seasonal semideciduous forest at Viçosa, Minas Gerais State, Brazil

    Directory of Open Access Journals (Sweden)

    Érica Pereira de Campos

    2009-06-01

    Full Text Available Este estudo objetivou avaliar a composição florística, a densidade e a freqüência de sementes, em 25 coletores, em um trecho de Floresta Estacional Semidecidual. Além disso, classificar os táxons quanto à forma de vida, às síndromes de dispersão e, nas arbóreas, quanto ao estádio sucessional e verificar a similaridade florística entre as espécies identificadas na chuva de sementes e as espécies arbóreas localizadas nas mesmas parcelas dos coletores. O trabalho foi realizado entre dezembro/2004 a novembro/2006. Foram reconhecidos 43 táxons, sendo que Leguminosae foi representada por 11 espécies. A forma de vida dominante foi arbórea (63,1%, as lianas foram representadas por 28,9% das espécies amostradas, as herbáceas por 5,3% e as arbustivas por 2,6%. A densidade média de sementes no primeiro ano foi de 113,92 sementes.m-2 e no segundo de 2.603,84 sementes.m-2. Essas diferenças demonstraram heterogeneidade espacial e temporal da chuva de sementes. A similaridade florística encontrada pelo índice de Sørensen entre as espécies da chuva de sementes e as espécies arbóreas do trecho do fragmento estudado foi de 32%, valor considerado baixo (This study aims to evaluate the floristic composition, density and frequency of seeds in 25 traps in a section of seasonal semideciduous forest, as well as classify taxons as to life form, dispersal syndromes, and succession phase of the tree species, and verify floristic similarities between seed rain species and tree species located in the same plots. The work was carried out from December/2004 to November/2006. Forty three taxons were recognized and Leguminosae was represented by 11 species. The dominant life form was arboreal (63.1%, climbers were represented by 28.9% of the sampled species, herbs by 5.3% and shrubs by 2.6%. Mean seed density in the first year was 113.92 seeds.m-2 and 2603.84 seeds.m-2 in the second year. These differences showed spatial and seasonal heterogeneity

  2. Primeiro registro de Aedes albopictus em área da Mata Atlântica, Recife, PE, Brasil First report of Aedes albopictus in areas of rain forest in Brazil

    Directory of Open Access Journals (Sweden)

    Cleide MR de Albuquerque

    2000-06-01

    Full Text Available Pela primeira vez é registrada a presença do Aedes albopictus em remanescentes de Mata Atlântica, localizada em área urbana em Recife (Pernambuco, Brasil. As coletas foram realizadas em isca humana e em criadouros de formas jovens (ocos de árvores, bambus, bromélias e pneu. A presença de Ae. albopictus na região metropolitana do Recife representa um risco potencial do inter-relacionamento dessa espécie de mosquito com a população.This is the first report of the presence of Aedes albopictus in the native rain forest, near the urban area of Recife (State of Pernambuco, Brazil. Adult female mosquitoes were collected using human bait. Mosquitoes in aquatic stages were looked for in treeholes, bamboos, bromeliads and old tires. The existence of Ae. albopictus in the metropolitan area of Recife poses a potential risk for the interaction of this mosquito species with the urban human population.

  3. The genus Guerrerostrongylus (Nematoda: Heligmonellidae) in cricetid rodents from the Atlantic rain forest of Misiones, Argentina: emended description of Guerrerostrongylus zetta (Travassos, 1937) and description of a new species.

    Science.gov (United States)

    Digiani, María Celina; Notarnicola, Juliana; Navone, Graciela T

    2012-10-01

    Two species of Guerrerostrongylus Sutton and Durette-Desset, 1991, are reported in cricetid rodents from the Atlantic rain forest of Misiones, Argentina. Guerrerostrongylus zetta (Travassos, 1937) is redescribed on the basis of material collected from Oligoryzomys nigripes from Argentina and material loaned by CHIOC from Brazil. It is characterized by a synlophe with about 40-45 (35-48) well-developed cuticular ridges, caudal bursa with long rays 6 and dorsal ray divided at mid-length, and well-sclerotized spicules with marked twisting. It was found with a prevalence of 100% in O. nigripes (14 hosts examined); however, it was not found in its type host Nectomys squamipes (4 hosts examined). Guerrerostrongylus ulysi n. sp., which is described from Sooretamys angouya , differs from the remaining species in the genus mainly by a synlophe with a strong reduction of the cuticular ridges and struts on the right side, and by a heart-shaped caudal bursa, with short rays 6 and a dorsal ray divided distally. It was found with a prevalence of 100% in 5 hosts examined.

  4. Enzymatic activities and stable isotope patterns of ectomycorrhizal fungi in relation to phylogeny and exploration types in an afrotropical rain forest.

    Science.gov (United States)

    Tedersoo, Leho; Naadel, Triin; Bahram, Mohammad; Pritsch, Karin; Buegger, Franz; Leal, Miguel; Kõljalg, Urmas; Põldmaa, Kadri

    2012-09-01

    Ectomycorrhizal (ECM) fungi obtain both mineral and simple organic nutrients from soil and transport these to plant roots. Natural abundance of stable isotopes (¹⁵N and ¹³C) in fruit bodies and potential enzymatic activities of ECM root tips provide insights into mineral nutrition of these mutualistic partners. By combining rDNA sequence analysis with enzymatic and stable isotope assays of root tips, we hypothesized that phylogenetic affinities of ECM fungi are more important than ECM exploration type, soil horizon and host plant in explaining the differences in mineral nutrition of trees in an African lowland rainforest. Ectomycorrhizal fungal species belonging to extraradical mycelium-rich morphotypes generally displayed the strongest potential activities of degradation enzymes, except for laccase. The signature of ¹⁵N was determined by the ECM fungal lineage, but not by the exploration type. Potential enzymatic activities of root tips were unrelated to ¹⁵N signature of ECM root tip. The lack of correlation suggests that these methods address different aspects in plant nutrient uptake. Stable isotope analysis of root tips could provide an additional indirect assessment of fungal and plant nutrition that enables enhancement of taxonomic coverage and control for soil depth and internal nitrogen cycling in fungal tissues.

  5. Identity crisis in "The Rain Child"

    Institute of Scientific and Technical Information of China (English)

    赵亭亭

    2008-01-01

    In the short story "The Rain Child" , Canadian Margaret Laurence gives a clear outline of encounters between the European culture and the African culture. This thesis analyzes the meaning of culture and cultural identity. It focuses on the different psychological states of Ruth, the heroine, under different social circumstances. It explains how her cultural identity crisis is generated. As the final analysis, fierce cultural conflicts and contradictions are caused by the misunderstanding of different cultural groups.

  6. Evolution in African tropical trees displaying ploidy-habitat association: The genus Afzelia (Leguminosae).

    Science.gov (United States)

    Donkpegan, Armel S L; Doucet, Jean-Louis; Migliore, Jérémy; Duminil, Jérôme; Dainou, Kasso; Piñeiro, Rosalía; Wieringa, Jan J; Champluvier, Dominique; Hardy, Olivier J

    2017-02-01

    Polyploidy has rarely been documented in rain forest trees but it has recently been found in African species of the genus Afzelia (Leguminosae), which is composed of four tetraploid rain forest species and two diploid dry forest species. The genus Afzelia thus provides an opportunity to examine how and when polyploidy and habitat shift occurred in Africa, and whether they are associated. In this study, we combined three plastid markers (psbA, trnL, ndhF), two nuclear markers (ribosomal ITS and the single-copy PEPC E7 gene), plastomes (obtained by High Throughput Sequencing) and morphological traits, with an extensive taxonomic and geographic sampling to explore the evolutionary history of Afzelia. Both nuclear DNA and morphological vegetative characters separated diploid from tetraploid lineages. Although the two African diploid species were well differentiated genetically and morphologically, the relationships among the tetraploid species were not resolved. In contrast to the nuclear markers, plastid markers revealed that one of the diploid species forms a well-supported clade with the tetraploids, suggesting historical hybridisation, possibly in relation with genome duplication (polyploidization) and habitat shift from dry to rain forests. Molecular dating based on fossil-anchored gene phylogenies indicates that extant Afzelia started diverging c. 14.5 or 20Ma while extant tetraploid species started diverging c. 7.0 or 9.4Ma according to plastid and nuclear DNA, respectively. Additional studies of tropical polyploid plants are needed to assess whether the ploidy-habitat association observed in African Afzelia would reflect a role of polyploidization in niche divergence in the tropics.

  7. ACTS Rain Fade Compensation

    Science.gov (United States)

    Coney, Thom A.

    1996-01-01

    Performance status of the Adaptive Rain Fade Compensation includes: (1) The rain fade protocol is functional detecting fades, providing an additional 10 dB of margin and seamless transitions to and from coded operation; (2) The stabilization of the link margins and the optimization of rain fade decision thresholds has resulted in improved BER performance; (3) Characterization of the fade compensation algorithm is ongoing.

  8. Seed rain, soil seed bank, and natural regeneration of natural Toona ciliata var.pubescens forest%毛红椿天然林种子雨、种子库与天然更新

    Institute of Scientific and Technical Information of China (English)

    黄红兰; 张露; 廖承开

    2012-01-01

    2008-2011年,调查江西九连山国家级自然保护区毛红椿天然林的种子雨、种子库及林下幼苗数量.结果表明:在毛红椿天然林,种子雨散布时间为10月下旬至12月下旬.2010年不同样地的种子雨强度为虾公塘气象观测站(320.3±23.5粒·m-2)>虾公塘保护站(284.7±24.2粒·m-2)>大丘田保护站(251.6±24.7粒·m-2),分别以222.0、34.3和22.6粒·m-2完好种子供土壤萌发更新;毛红椿种子储量取决于结实量、鸟类取食和种子活力等因素,鸟类取食是其种子储量大幅下降的首要因素;由于种子不耐储藏以及大量腐烂,种子有效贮藏期不足1个月.12月天然林种子库平均萌发数≤2株·m-2,次年1月土壤种子库种子量最少,为6.7~11.8粒·m-2,平均仅萌发0.4~0.6株·m-2,与林下实生幼苗分布极少相吻合.毛红椿种子雨储备、种子库种子活力保存及幼苗建成等因素影响其天然更新.%Taking the natural Toona ciliata var. pubescens forest in the Jiujiangshan National Nature Reserve in Jiangxi Province of China as test object, an investigation was conducted on the seed rain, soil seed bank, and seedlings number in 2008-2011. The seed rain of the forest was dispersed from late October to the end of December. In 2010, the seed rain intensity in different sampling plots was in the order of Xiagongtang observatory (320. 3+23. 5 seeds · m-2) > Xiagongtang protection station (284.7±24. 2 seeds · m-2) > Daqiutian protection station (251. 6±24. 7 seeds · m-2) , and the quantity of the intact seeds in soil supplied for seed germination and regeneration was 222. 0, 34. 3 , and 22.6 seeds · m-2 , respectively. The seed bank reserves was affected by the seed production amount, bird feeding, and seed viability, etc. , of which, bird feeding was the prime factor for the substantial drop of the seed bank reserves. Due to the low resistance against storage and a large number of rot during storage, the seeds in soil

  9. Tree size and light availability increase photochemical instead of non-photochemical capacities of Nothofagus nitida trees growing in an evergreen temperate rain forest.

    Science.gov (United States)

    Coopman, Rafael E; Briceño, Verónica F; Corcuera, Luis J; Reyes-Díaz, Marjorie; Alvarez, Daniela; Sáez, Katherine; García-Plazaola, José I; Alberdi, Miren; Bravo, León A

    2011-10-01

    Nothofagus nitida (Phil.) Krasser (Nothofagaceae) regenerates under the canopy in microsites protected from high light. Nonetheless, it is common to find older saplings in clear areas and adults as emergent trees of the Chilean evergreen forest. We hypothesized that this shade to sun transition in N. nitida is supported by an increase in photochemical and non-photochemical energy dissipation capacities of both photosystems in parallel with the increase in plant size and light availability. To dissect the relative contribution of light environment and plant developmental stage to these physiological responses, the photosynthetic performance of both photosystems was studied from the morpho-anatomical to the biochemical level in current-year leaves of N. nitida plants of different heights (ranging from 0.1 to 7 m) growing under contrasting light environments (integrated quantum flux (IQF) 5-40 mol m(-2). Tree height (TH) and light environment (IQF) independently increased the saturated electron transport rates of both photosystems, as well as leaf and palisade thickness, but non-photochemical energy flux, photoinhibition susceptibility, state transition capacity, and the contents of D1 and PsbS proteins were not affected by IQF and TH. Spongy mesophyll thickness and palisade cell diameter decreased with IQF and TH. A(max), light compensation and saturation points, Rubisco and nitrogen content (area basis) only increased with light environment (IQF), whereas dark respiration (R(d)) decreased slightly and relative chlorophyll content was higher in taller trees. Overall, the independent effects of more illuminated environment and tree height mainly increased the photochemical instead of the non-photochemical energy flux. Regardless of the photochemical increase with TH, carbon assimilation only significantly improved with higher IQF. Therefore it seems that mainly acclimation to the light environment supports the phenotypic transition of N. nitida from shade to

  10. Rain Forests(高一适用)

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    More than 50,000,000 people of the world live in rain forests andmost of them do not hurt the forests theylive in. They eat the fruits that grow onthe trees, but they do not cut them down.They kill animals for food, but they do notdestroy them.

  11. 西双版纳热带季节雨林树种的区系组成成分分析%Floristic Composition of Tropical Seasonal Rain Forests in Xishuangbanna

    Institute of Scientific and Technical Information of China (English)

    兰国玉; 朱华; 曹敏

    2013-01-01

    按照美国史密森热带研究所的热带森林研究中心1980年在巴拿马Barro Colorado Island 地区建立50 hm2样地的技术规范,2007年在西双版纳州勐腊县补蚌村的望天树林中建立了一块面积为20 hm2的热带森林动态监测样地,逐一测量记录了样地中所有树干胸径≥1 cm树木的胸围,并对其挂牌标记、鉴定种名、确定坐标位置.基于此资料分析了科、属的分布区类型,并与马来西亚的热带季节雨林样地(Lambir和Pasoh)和泰国热带雨林样地(HKK)样地内优势科和优势种做了比较.结果表明:1)西双版纳热带季节雨林样地中热带成分的科有51个,热带成分的属有186个,分别占总科数和总属数的72.87%和89.42%;温带成分的科和属各有3个,分别占总科数和总属数的4.29%和1.44%.反映了样地植物区系组成成分的热带性质,温带成分占有一部分比例,则体现了群落的温带性质.2)马来西亚和泰国热带雨林的一些优势科,如龙脑香科、藤黄科、肉豆蔻科,在西双版纳热带季节雨林样地同样占有非常重要的地位,反映了西双版纳热带季节雨林与东南亚热带雨林在科的组成上有很大的相似性.但龙脑香科、野牡丹科、藤黄科、山榄科、橄榄科等一些科在马来西亚有大量的发展,在西双版纳热带季节雨林中这些科的物种数相对较少.%A plot with an area of 20 hmz was established in a dipterocarp forest in Mengla Nature Reserve in 2007. The construction technology and field protocol followed those applied in the establishment of the 50 hmz plot in the tropical forest of Barro Colorado Island in Panama, developed by Center for Tropical Forest Science,Smithsonian Tropical Research Institute in 1980. All free-standing trees with DBH ≥1 cm were tagged,mapped, measured (girth) and identified to species in the plot. Based on trees with DBH≥ 1 cm in a 20 hm2 stem-mapped tropical seasonal rain forest in

  12. Combining moving inlets for measuring gradients of reactive trace gases and thoron measurements for the determination of near surface fluxes -first results from the Amazon rain forest-

    Science.gov (United States)

    Sörgel, Matthias; Artaxo, Paulo; Kesselmeier, Jürgen; Quesada, Carlos Alberto; Ferreira de Souza, Rodrigo Augusto; Trebs, Ivonne; Vega, Oscar; Yañez-Serrano, Ana Maria

    2016-04-01

    For many compounds of interest no fast response sensors for the determination of eddy covariance fluxes are available. Therefore, flux-gradient relationships are used. The most common are the aerodynamic gradient method and the modified Bowen ratio method. For those approaches some assumptions have to be made which restrict their use. An alternative approach to calculate these fluxes might be given by the "thoron clock" method. The radon isotope Thoron (220Rn) is exhaled from the soil and has a half life time of 56 seconds. Therefore, it exists in measureable amounts only close to the ground and is hardly advected. Its only source is the radioactive decay of Thorium in soil. As it is a noble gas Thoron is not influenced by biochemical processes in air. Consequently, its concentration profile only depends on vertical mixing and the radioactive decay which is a physical constant. According to Lehmann et al. (1999) and Plake and Trebs (2013) a transport-time can be directly calculated from two heights thoron concentration/activity for the layer in-between without further assumptions. From this transport time the transfer velocity is derived which is then applied to calculate the fluxes of other (reactive) trace gases. A major advantage of the method is that the transport-time is known and using the measured concentration profile the chemical loss of a compound can be directly calculated and corrected for. We have applied this method for a first time in the Amazon rainforest during a field campaign at the ATTO site 150 km North East of Manaus in the dry season of 2014. We measured gradients of NO, NO2, O3, HONO and VOCs by using a movable inlet on a lift system close to the forest floor (0.19 m, 0.52 m and 1.59 m). A Thoron profile was measure in parallel at the lower two heights. First results of the gradients, the transport times and some preliminary flux values will be presented. References: Lehmann, B.E., Lehmann, M., Neftel, A .: 220 Radon calibration of near

  13. CARBON CYCLING OF TROPICAL-RAIN FOREST AND ITS IMPLICATION%热带雨林的碳循环及其意义

    Institute of Scientific and Technical Information of China (English)

    张洪波; 管东生; 郑淑颖

    2001-01-01

    Because tropical rainforest has a great amount of biomass and primary production, it has a good ability for fixing CO2, which could make the “greenhouse effect” on the earth. The carbon cycling of tropical rainforest has become a hot point for research. This cycling is characterized by short cycling period, giant storage, strong complexity and closing. The carbon cycling of tropical rainforest contains three main processes, such as carbon fixation, returning and recycling, losing and storage. It could enormously influence the global carbon cycling, global change, ecosystem, sustainable development and human life. Great attention should be paid to better management and conservation of tropical forest, and more research work need to be done, as a large amount of carbon is released into the atmosphere that results in many environmental problems due to irrational land use in tropical rainforest.%热带雨林的碳循环及其在全球碳循环中的作用,已经成为当前的热点研究问题。热带雨林的碳循环包括植物的固碳作用、归还作用和再利用、流失及贮存三个过程,并具有周期短、贮存量大、复杂性及封闭性强的特点。而且热带雨林的碳循环对全球碳循环、全球变化、生态系统、环境和可持续发展以及人类本身有巨大影响,但是由于热带林地的土地利用每年造成相当大的碳净释放,并带来一系列的环境问题,因此深入开展对热带雨林的研究,以及合理利用、开发和保护,实现热带雨林的可持续发展意义十分重大。

  14. A Study on the Pometia tomentosa Community of Tropical Seasonal Rain Forest in Dahei Mountain, Lixian River Watershed,Southeastern Yunnan%滇东南李仙江大黑山热带季节性雨林番龙眼群落研究

    Institute of Scientific and Technical Information of China (English)

    周虹霞; 朱华; 王洪; 肖文祥

    2001-01-01

    滇东南绿春县李仙江大黑山番龙眼群落以无患子科的番龙眼和苏木科的无忧花为乔木层优势种,外貌以单叶、纸质、全缘、渐尖、中叶为主的常绿大、中高位芽植物组成为特征,层间木质藤本较丰富,属一种热带北缘的热带季节性雨林类型。该群落物种组成复杂,动态结构稳定,处于生长期。%The Pometia tomentosa forest in Dahei Mountain, Lixian RiverWatershed, southeastern Yunnan,is dominated by Pometia tomentosa and Saraca dives, and is charactered by evergreen megaphaenerophytes and mesophaenerophytes with simple ,chartaceous and entire mesophylls. With the conspicuous similarity on ecological and floristic characters to tropical rain forest of SE Asia, the forest in Dahei Mountain is considered as a type of tropical seasonal rain forest in the northern margin of tropical Asia. Furthermore, the distribution of trees in DBH class, the individual/ tree species relation and the frequency of tree species are enumerated.

  15. Specific and generic stem biomass and volume models of tree species in a West African tropical semi-deciduous forest

    DEFF Research Database (Denmark)

    Goussanou, Cédric A.; Guendehou, Sabin; Assogbadjo, Achille E.

    2016-01-01

    The quantification of the contribution of tropical forests to global carbon stocks and climate change mitigation requires availability of data and tools such as allometric equations. This study made available volume and biomass models for eighteen tree species in a semi-deciduous tropical forest...... in West Africa. Generic models were also developed for the forest ecosystem, and basic wood density determined for the tree species. Non-destructive sampling approach was carried out on five hundred and one sample trees to analyse stem volume and biomass. From the modelling of volume and biomass...... predictive ability for biomass. Given tree species richness of tropical forests, the study demonstrated the hypothesis that species-specific models are preferred to generic models, and concluded that further research should be oriented towards development of specific models to cover the full range...

  16. Forest vegetation of Xishuangbanna, south China

    Institute of Scientific and Technical Information of China (English)

    Zhu Hua

    2006-01-01

    Xishuangbanna of southern Yunnan is biogeographically located at a transitional zone from tropical southeast (SE) Asia to subtropical east Asia and is at the junction of the Indian and Burmese plates of Gondwana and the Eurasian plate of Laurasia. The region, though surprisingly far from the equator and at a relatively high altitude, has a rich tropical flora and a typical tropical rain forest in the lowland areas. Based on physiognomic and ecological characteristics, floristic composition and habitats combined, the primary vegetation in Xishuangbanna can be organized into four main vegetation types: tropical rain forest, tropical seasonal moist forest, tropical montane evergreen broad-leaved forest and tropical monsoon forest. The tropical rain forest can be classified into two subtypes, i.e. a tropical seasonal rain forest in the lowlands and a tropical montane rain forest at higher elevations. The tropical seasonal rain forest has almost the same forest profile and physiognomic characteristics as equatorial lowland rain forests and is a type of truly tropical rain forest. Because of conspicuous similarity on ecological and floristic characteristics, the tropical rain forest in Xishuangbanna is a type of tropical Asian rain forest. However, since the tropical rain forest of Xishuangbanna occurs at the northern edge of tropical SE Asia, it differs from typical lowland rain forests in equatorial areas in having some deciduous trees in the canopy layer, fewer megaphanerophytes and epiphytes but more abundant lianas and more plants with microphyll. It is a type of semi-evergreen rain forest at the northern edge of the tropical zone. The tropical montane rain forest occurs at wet montane habitats and is similar to the lower montane rain forest in equatorial Asia in floristic composition and physiognomy. It is a type of lower montane rain forests within the broader category of tropical rain forests. The tropical seasonal moist forest occurs on middle and upper

  17. Acid rain and its ecological consequences.

    Science.gov (United States)

    Singh, Anita; Agrawal, Madhoolika

    2008-01-01

    Acidification of rain-water is identified as one of the most serious environmental problems of transboundary nature. Acid rain is mainly a mixture of sulphuric and nitric acids depending upon the relative quantities of oxides of sulphur and nitrogen emissions. Due to the interaction of these acids with other constituents of the atmosphere, protons are released causing increase in the soil acidity Lowering of soil pH mobilizes and leaches away nutrient cations and increases availability of toxic heavy metals. Such changes in the soil chemical characteristics reduce the soil fertility which ultimately causes the negative impact on growth and productivity of forest trees and crop plants. Acidification of water bodies causes large scale negative impact on aquatic organisms including fishes. Acidification has some indirect effects on human health also. Acid rain affects each and every components of ecosystem. Acid rain also damages man-made materials and structures. By reducing the emission of the precursors of acid rain and to some extent by liming, the problem of acidification of terrestrial and aquatic ecosystem has been reduced during last two decades.

  18. Observações sobre atividade de mosquitos Culicidae em mata primitiva da encosta no Vale do Ribeira, São Paulo, Brasil Observations on mosquito activity in primitive highland rain forest in the Ribeira Valley, S. Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Oswaldo Paulo Forattini

    1986-02-01

    Full Text Available Relatam-se observações sobre o ciclo diário de atividade culicídea em ambiente primitivo da floresta perenifólia higrófila da encosta, do Sistema da Serra do Mar, no Vale do Ribeira, Estado de São Paulo, Brasil. Com periodicidade bimensal, e no período de dois anos, foram levadas a efeito coletas de vinte e cinco horas ininterruptas com o emprego de isca humana, bem como a utilização de armadilhas tipo Shannon operadas dentro e fora do ambiente florestal. Os resultados evidenciaram acentuada dominancia de An. cruzii, que se manteve durante todos os meses do ano mesmo naqueles de menor atividade culicídea. A influência crepuscular evidenciou-se pela nítida ocorrência de picos endocrepusculares para An. cruzii e An. bellator, seguidos imediatamente por outros, de menor intensidade, caracterizando assim ritmo que se propõe chamar de paracrepuscular. Ambas essas espécies de Kerteszia apresentaram atividade contínua para a isca humana, no período das 24 horas. Cx. sacchettae mostrou-se nitidamente noturna e com ritmo eocrepuscular. Ae. serratus e Ps. ferox revelaram-se essencialmente diurnos, com certa tendência ao ritmo paracrepuscular porém, até onde foi possível observar, de maneira incompleta e limitado ao crepúsculo matutino. A atividade ininterrupta, aliada à densidade e dominância de An. cruzii reafirma sua importância epidemiológica e a torna uma das feições que caracteriza o ambiente primitivo supracitado.With fortnightly rhythm, 25-hour catches of Culicidae mosquitoes were carried out, at ground level, with human bait, in a primitive rain forest in a highland relief area of the Ribeira Valley region, S. Paulo, Brazil. Besides this, regular simultaneous catches employing Shannon traps were made within and outside the forest environment. Results obtained are presented and discussed. An. cruzii proved a highly dominant species and An. bellator also showed ininterrupted daily activity, increasing at night. They

  19. RAINE Public Communities

    Data.gov (United States)

    U.S. Environmental Protection Agency — The file geodatabase (fgdb) contains the New England Town Boundaries and information related specifically to the Resilience and Adaptation in New England (RAINE) web...

  20. Acid rain: An overview

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Summary of the effects of acid rain and related processes, sources, issues, corrective actions, research, current law, potential solutions, political solutions,...

  1. Is sexual size dimorphism in relative head size correlated with intersexual dietary divergence in West African forest cobras, Naja melanoleuca?

    NARCIS (Netherlands)

    Luiselli, Luca; Akani, Godfrey C.; Corti, Claudia; Angelici, Francesco M.

    2002-01-01

    Sex-biased differences in dietary habits of snakes are often linked to pronounced sexual size dimorphism in absolute body size or in relative head size. We studied the food habits of free-ranging forest cobras (Naja melanoleuca) in southern Nigeria to find whether any intersexual dietary divergence

  2. Habitat differences in dung beetle assemblages in an African savanna-forest ecotone: implications for secondary seed dispersal.

    Science.gov (United States)

    Kunz, Britta K; Krell, Frank-Thorsten

    2011-06-01

    The probability and pattern of secondary seed dispersal by dung beetles (Scarabaeinae) depend on their community structure and composition at the site of primary deposition, which, in turn, seem to be strongly determined by vegetation. Consequently, we expected pronounced differences in secondary seed dispersal between forest and savanna in the northern Ivory Coast, West Africa. We found 99 dung beetle species at experimentally exposed dung piles of the olive baboon (Papio anubis (Lesson, 1827)), an important primary seed disperser in West Africa. Seventy-six species belonged to the roller and tunneler guilds, which are relevant for secondary seed dispersal. Most species showed a clear habitat preference. Contrary to the Neotropics, species number and abundance were much higher in the savanna than in the forest. Rollers and tunnelers each accounted for approximately 50% of the individuals in the savanna, but in the forest rollers made up only 4%. Seeds deposited into the savanna by an omnivorous primary disperser generally have a higher overall probability of being more rapidly dispersed secondarily by dung beetles than seeds in the forest. Also, rollers disperse seeds over larger distances. In contrast to other studies, small rollers were active in dispersal of large seeds, which were seemingly mistaken for dung balls. Our results suggest that rollers can remove seeds from any plant dispersed in primate dung in this ecosystem.

  3. Photo-Activitied Antimicrobial Activities Screening of 10 Tropical Rain Forest Plants%十种热带雨林植物光活化抗微生物活性的筛选

    Institute of Scientific and Technical Information of China (English)

    胡昀; 陈玉

    2012-01-01

    为从植物中寻找具有光调节生物活性的物质,通过滤纸片法和薄层色谱自显影技术,以金黄色葡菌球菌(Staphylococcus aureus)、枯草芽胞杆菌(Bacillus subtilis)、草分枝杆菌(Mycobacteium phlei)、环状芽胞杆菌(Bacillus circulans)为供试菌,对10种热带雨林植物进行光活化抗微生物活性的筛选和活性部位的确定.结果表明:0.1mg的狗花椒(Y10)氯仿提取物对枯草芽胞杆菌具有明显的光活化抗微生物活性,在紫外光照射后和黑暗中抑菌圈相差4mm,薄层色谱中0.5mg Y10氯仿提取物抗枯草芽胞杆菌的抑菌圈最大.本研究为进一步从该植物中寻找新型光敏剂奠定了基础.%To find the light-medidated biological active substances, 10 tropical rain forest plants were screened by the paper disc method and thin-layer chromatography bioautography technique to test their antimicrobial activity Staphylococcus aureus,Bacillus subtilis, Mycobacteium phlei and Bacillus circulan were employed as samples. The results showed that 0. ling of Zanthoxylum planispinum sieb. et Zucc. (Y10) chloroform extracts have obvious photo-aetivitied antimicrobial activities for Bacillus subtilis. The antibacterial circle difference between the uhra-violet light and darkness is 4mm. And 0.5rag Y10 chloroform extracts have maximum inhibition zone for Bacillus subtilis in thin-layer chromatography. Our study can be used for further investigation in novel photosensitizers.

  4. Coupled carbon-water exchange of the Amazon rain forest, II. Comparison of predicted and observed seasonal exchange of energy, CO2, isoprene and ozone at a remote site in Rondônia

    Directory of Open Access Journals (Sweden)

    E. Simon

    2005-01-01

    Full Text Available A one-dimensional multi-layer scheme describing the coupled exchange of energy and CO2, the emission of isoprene and the dry deposition of ozone is applied to a rain forest canopy in southwest Amazonia. The model was constrained using mean diel cycles of micrometeorological quantities observed during two periods in the wet and dry season 1999. Calculated net fluxes and concentration profiles for both seasonal periods are compared to observations made at two nearby towers. The modeled day- and nighttime thermal stratification of the canopy layer is consistent with observations in dense canopies. The observed and modeled net fluxes above and H2O and CO2 concentration profiles within the canopy show a good agreement. The predicted net carbon sink decreases from 2.5 t C ha-1 yr-1 for wet season conditions to 1 t C ha-1 yr-1 for dry season conditions, whereas observed and modeled midday Bowen ratio increases from 0.5 to 0.8. The evaluation results confirmed a seasonal variability of leaf physiological parameters, as already suggested in a companion study. The calculated midday canopy net flux of isoprene increased from 7.1 mg C m-2 h-1 during the wet season to 11.4 mg C m-2 h-1 during the late dry season. Applying a constant emission capacity in all canopy layers, resulted in a disagreement between observed and simulated profiles of isoprene concentrations, suggesting a smaller emission capacity of shade adapted leaves and deposition to the soil or leaf surfaces. Assuming a strong light acclimation of emission capacity, equivalent to a 66% reduction of the standard emission factor for leaves in the lower canopy, resulted in a better agreement of observed and modeled concentration profiles and a 30% reduction of the canopy net flux compared to model calculations with a constant emission factor. The mean calculated ozone flux for dry season conditions at noontime was ≈12 n mol m-2 s-1, agreeing well with observed values. The corresponding deposition

  5. Influence of Atlantic Rain Forest remnants on the biological control of Euselasia apisaon (Dahman) (Lepidoptera: Riodinidae) by Trichogramma maxacalii (Voegele and Pointel) (Hymenoptera: Trichogrammatidae); Efeitos de remanescentes de Mata Atlantica no controle biologico de Euselasia apisaon (Dahman) (Lepidoptera: Riodinidae) por Trichogramma maxacalii (Voegele e Pointel) (Hymenoptera: Trichogrammatidae)

    Energy Technology Data Exchange (ETDEWEB)

    Murta, Aline F.; Ker, Fabricio T.O.; Costa, Dalbert B. [Centro Universitario do Leste de Minas Gerais (UnilesteMG), Coronel Fabriciano, MG (Brazil). Lab. de Controle Biologico de Pragas; Espirito-Santo, Mario M.; Faria, Mauricio L. [Universidade Estadual de Montes Claros, MG (Brazil). Centro de Ciencias Biologicas e da Saude. Dept. de Biologia Geral

    2008-03-15

    This study evaluated the effects of Atlantic Rain Forest remnants on the natural biological control of Euselasia apisaon (Dahman) by the parasitoid Trichogramma maxacalii (Voegele and Pointel) in Eucalyptus plantations. The number of E. apisaon eggs/leaf was higher in the center than in the edge of the plantations (23.5 {+-} 7.61 vs. 14.8 {+-} 3.14), but parasitism showed the reversed pattern (72.4% in the center and 80.5% in the edge). The results indicated that natural regulation exerted by T. maxacalii on populations of E. apisaon may be enhanced by the preservation of fragments of native vegetation surrounding Eucalyptus plantations. (author)

  6. The Eastern Arc Mountains and coastal forests of East Africa-an archive to understand large-scale biogeographical patterns: Pseudotomias, a new genus of African Pseudophyllinae (Orthoptera: Tettigoniidae).

    Science.gov (United States)

    Hemp, Claudia

    2016-06-21

    A new genus of Pseudophyllinae restricted to East Africa is described. Data on the ecology, and the habitat are provided. The biogeographical pattern and morphology suggests an old radiation since Tomias from Central and West Africa is the closest relative to Pseudotomias. The old forests of East Africa could hereby be the source of representatives of this old radiation since venation is less reduced in East African taxa of Phyllomimini.

  7. Waving in the rain

    CERN Document Server

    Cavaleri, Luigi; Bidlot, Jean-Raymond

    2015-01-01

    We consider the effect of rain on wind wave generation and dissipation. Rain falling on a wavy surface may have a marked tendency to dampen the shorter waves in the tail of the spectrum, the related range increasing with the rain rate. Following the coupling between meteorological and wave models, we derive that on the whole this should imply stronger wind and higher waves in the most energetic part of the spectrum. This is supported by numerical experiments. However, a verification based on the comparison between operational model results and measured data suggests that the opposite is true. This leads to a keen analysis of the overall process, in particular on the role of the tail of the spectrum in modulating the wind input and the white-capping. We suggest that the relationship between white-capping and generation by wind is deeper and more implicative than presently generally assumed.

  8. The value of rain

    NARCIS (Netherlands)

    Snellen, W.B.

    2006-01-01

    This paper explores the gains that can be made by shifting the focus of water resources management from the water towards the rain. This causes also a shift in perception of what is the largest user of water: instead of irrigation it is the evapotranspiration

  9. Rain of Seattle

    Institute of Scientific and Technical Information of China (English)

    Julie Jindal

    2006-01-01

    @@ I've got a deep secret few people understand and even fewer will admit to sharing. It's time to tell the truth: I love the rain, deeply and passionately and more than the sun. At least I live in the right place, famous for its damp weather and spawning its own genuine rainforest.

  10. After the Rain: Animals.

    Science.gov (United States)

    Old Elk, Arlene; Stoklas, Jackie

    The Heard Museum (Phoenix, Arizona) has developed and updated an integrated curriculum for use in grades K-3. The goals for this curriculum are to: (1) share museum resources with schools; (2) promote cross-cultural understanding through a focus on rain, a universal requirement for life; (3) help students understand that Native Americans are…

  11. Acid Rain Investigations.

    Science.gov (United States)

    Hugo, John C.

    1992-01-01

    Presents an activity in which students investigate the formation of solid ammonium chloride aerosol particles to help students better understand the concept of acid rain. Provides activity objectives, procedures, sample data, clean-up instructions, and questions and answers to help interpret the data. (MDH)

  12. The Acid Rain Game.

    Science.gov (United States)

    Rakow, Steven J.; Glenn, Allen

    1982-01-01

    Provides rationale for and description of an acid rain game (designed for two players), a problem-solving model for elementary students. Although complete instructions are provided, including a copy of the game board, the game is also available for Apple II microcomputers. Information for the computer program is available from the author.…

  13. Acid Rain Classroom Projects.

    Science.gov (United States)

    Demchik, Michael J.

    2000-01-01

    Describes a curriculum plan in which students learn about acid rain through instructional media, research and class presentations, lab activities, simulations, design, and design implementation. Describes the simulation activity in detail and includes materials, procedures, instructions, examples, results, and discussion sections. (SAH)

  14. Rain Drop Charge Sensor

    Science.gov (United States)

    S, Sreekanth T.

    begin{center} Large Large Rain Drop Charge Sensor Sreekanth T S*, Suby Symon*, G. Mohan Kumar (1) , S. Murali Das (2) *Atmospheric Sciences Division, Centre for Earth Science Studies, Thiruvananthapuram 695011 (1) D-330, Swathi Nagar, West Fort, Thiruvananthapuram 695023 (2) Kavyam, Manacaud, Thiruvananthapuram 695009 begin{center} ABSTRACT To study the inter-relations with precipitation electricity and precipitation microphysical parameters a rain drop charge sensor was designed and developed at CESS Electronics & Instrumentation Laboratory. Simultaneous measurement of electric charge and fall speed of rain drops could be done using this charge sensor. A cylindrical metal tube (sensor tube) of 30 cm length is placed inside another thick metal cover opened at top and bottom for electromagnetic shielding. Mouth of the sensor tube is exposed and bottom part is covered with metal net in the shielding cover. The instrument is designed in such a way that rain drops can pass only through unhindered inside the sensor tube. When electrically charged rain drops pass through the sensor tube, it is charged to the same magnitude of drop charge but with opposite polarity. The sensor tube is electrically connected the inverted input of a current to voltage converter operational amplifier using op-amp AD549. Since the sensor is electrically connected to the virtual ground of the op-amp, the charge flows to the ground and the generated current is converted to amplified voltage. This output voltage is recorded using a high frequency (1kHz) voltage recorder. From the recorded pulse, charge magnitude, polarity and fall speed of rain drop are calculated. From the fall speed drop diameter also can be calculated. The prototype is now under test running at CESS campus. As the magnitude of charge in rain drops is an indication of accumulated charge in clouds in lightning, this instrument has potential application in the field of risk and disaster management. By knowing the charge

  15. Weighing Rain Gauge Recording Charts

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Weighing rain gauge charts record the amount of precipitation that falls at a given location. The vast majority of the Weighing Rain Gauge Recording Charts...

  16. Coupled carbon-water exchange of the Amazon rain forest, II. Comparison of predicted and observed seasonal exchange of energy, CO2, isoprene and ozone at a remote site in Rondônia

    Directory of Open Access Journals (Sweden)

    J. Kesselmeier

    2005-04-01

    Full Text Available A one-dimensional multi-layer scheme describing the coupled exchange of energy and CO2, the emission of isoprene and the dry deposition of ozone is applied to a rain forest canopy in southwest Amazonia. The model was constrained using mean diel cycles of micrometeorological quantities observed during two periods in the wet and dry season 1999. Predicted net fluxes and concentration profiles for both seasonal periods are compared to observations made at two nearby towers. The predicted day- and nighttime thermal stratification of the canopy layer is consistent with observations in dense canopies. The observed and calculated net fluxes above and H2O and CO2 concentration profiles within the canopy show a good agreement. The predicted net carbon sink decreases from 2.5 t C ha-1yr-1 for wet season conditions to 1 t C ha-1yr-1 for dry season conditions, whereas observed and predicted midday Bowen ratio increases from 0.5 to 0.8. The evaluation results confirmed a seasonal variability of leaf physiological parameters, as already suggested in the companion study. The predicted midday canopy net flux of isoprene increased from 7.1 mg C m-2h-1 during the wet season to 11.4 mg C m-2h-1 during the late dry season. Applying a constant emission capacity in all canopy layers, resulted in a disagreement between observed and simulated profiles of isoprene concentrations, suggesting a smaller emission capacity of shade adapted leaves and deposition to the soil or leaf surfaces. Assuming a strong light acclimation of emission capacity, equivalent to a 66% reduction of the standard emission factor for leaves in the lower canopy, resulted in a better agreement of observed and calculated concentration profiles and a 30% reduction of the canopy net flux. The mean calculated ozone flux for dry season condition at noontime was ≈12 nmol m-2s-1, agreeing well with observed values. The corresponding deposition velocity increased from 0.8 cm s-1 to >1.6 cm s-1 in the wet

  17. When It Rains, It Pours

    Science.gov (United States)

    Mills, Linda

    2012-01-01

    "It's raining, it's pouring, the old man is snoring!" "The itsy, bitsy spider crawled up the waterspout, down came the rain and washed the spider out. Out came the sun and dried up all the rain, and the itsy, bitsy spider went up the spout again." What do children's nursery rhymes have to do with the school library? The author begins by telling a…

  18. Enrichment of Logging Gaps with a High Conservation Value Species (Pericopsis elata in a Central African Moist Forest

    Directory of Open Access Journals (Sweden)

    Dakis-Yaoba Ouédraogo

    2014-12-01

    Full Text Available In central Africa, most of the timber species require high light at the seedling stage for survival and growth. Forest managers face a regeneration shortage of these light-demanding timber species. To achieve long-term sustainability, there is a need for enrichment methods combining low cost and high species performance. The aim of this study was to assess the performance of Pericopsis elata seedlings in enriched logging gaps in Cameroon. Over five years; the survival and size of each seedling was monitored in 27 logging gaps that were either left without maintenance or cleared. Gaps were relatively small with an average total area of 155 m2. We found that planted seedlings of P. elata performed well in logging gaps. Even without any maintenance 61% of the planted seedlings survived after five years with an average annual diameter increment of 0.28 cm. P. elata appeared to be a good candidate species for enrichment in logging gaps. We demonstrated that the seedlings of P. elata tolerated a wide range of soil conditions but that their performance was strongly influenced by light availability (gap clearance, suggesting potentially improved performance of P. elata in high light environments such as in plantation or larger gaps.

  19. Adaptive rain fade compensation

    Science.gov (United States)

    Rautio, J. C.

    1980-01-01

    A large available margin must be provided for satellite communications systems operating near 20 GHz, which occasionally experience fades due to rain attenuation. It is proposed that this margin may be achieved in high-capacity FDMA satellites by dynamically providing a large margin to those links which are experiencing deep fades, while maintaining a small fade margin on all others. Single-beam SCPC operation and multiple-beam, satellite-switched FDMA systems are described, and the optimization of the dynamic FDMA links in a severely fading environment is investigated. A solution is derived which takes into account: (1) transponder intermodulation distortion, (2) cochannel and cross-polarization antenna interference, and (3) rain fade characteristics. The sample system configuration presented shows that such systems reach availability levels approaching 0.9999 at Ka-Band.

  20. [Yesterday, today, tomorrow. A retrospective look at the acid rain problem].

    Science.gov (United States)

    Buijsman, Ed

    2008-01-01

    Last century, at the end of the seventies, Europe was startled by a serious environmental problem: acid rain. Acid rain was held responsible for the decline of fishes in Scandinavian lakes. Later, it was suggested that acid rain could lead to forest dieback over vast areas of Europe. Forests in the Netherlands could be at great risk, as well. It was clear to everyone what it was all about, for 'rain' means water falling from the atmosphere and the meaning of 'acid' was evident, too. Acid rain caused much commotion in the eighties but, since then, it has faded into the background. Why is it, that there is so little attention paid to acid rain these days? Maybe the acid rain problem was a hype; with an exaggerated reaction to a problem that was, in fact, insignificant. This article aims to reconstruct the history of one of the most prominent environmental problems of the twentieth century. The article describes the origin of the acid rain problem in the 1960s and describes the scientific research that was carried out to develop a better understanding of the problem from an atmospheric chemical point of view. Subsequently, it treats the rise of public awareness in the seventies. The article subsequently focuses on the situation in the Netherlands. The initial research into forest health showed alarming results. This led to widespread concern within The Netherlands, which, once more, urged the government to come into action. Some measures to reduce air-polluting emissions were already taken in the early 1980s. However, these were meant, mainly, to improve local air quality. As the eighties progressed, acid rain provided an additional argument for reducing air pollution. This article presents the consequences of the emission reductions for the acidity of acid rain, and it discusses--in brief--the acid rain problem in light of current scientific knowledge. Finally, it answers the question of why forests did not die.

  1. Species composition and diversity of soil mesofauna in the ‘ Holy Hills’ fragmentary tropical rain forest of Xishuang banna, China.%西双版纳“龙山”片断热带雨林中小型土壤动物群落 组成与多样性研究

    Institute of Scientific and Technical Information of China (English)

    杨效东; 沙丽清

    2001-01-01

    对西双版纳不同面积“龙山”片断干性季节雨林和保护区连续湿性季节雨林凋落物层土壤动物群落多样性研究表明,土壤动物群落物种丰盛度、多度和多样性的变化不存在随雨林片断化面积减小而降低的“种-面积效应”,而雨林片断化后因先锋植物(喜阳性)侵入产生的“干暖效应”,使片断化雨林凋落物增多,腐殖质、土壤有机质、N、P等元素含量增高,土壤生境条件更有利于土壤动物生存,其群落多样性指数高于连续湿性季节雨林,但2种生境土壤动物群落种-多度模型均表现为对数级模式.%The species composition and diversity of soil mesofauna were xamined in fragmented dry tropical seasonal rainforest of tow‘ Holy Hills’ of Dai nationality, compared with the continuous moist tropical seasonal rain forest of Nature Reserve in Xishuangbanna area. 5 sample quadrats were selected along the diagonal of 20m × 20m sampling plot, and the samples of litterfall and 0 ~ 3cm soil were collected from each 50cm × 10cm sample quadrat. Animals in soil sample were collected by using dry-funnel(Tullgren’s), were identified to their groups according to the order. The H′ index, D· G index and the pattern of relative abundance of species were used to compare the diversity of soil mesofauna. The results showed that the disturbance of vegetation and soil resulted by tropical rainforest fragmentation was the major factor affecting the diversity of soil mesofauna. Because the fragmented forest was intruded by some pioneer tree species and the “dry and warm” effect operated, this forest had more litterfall on the floor and more humus in the soil than the continuous moist rain forest. The soil condition with more soil organic matter, total N and P, higher pH value and lower soil bulk density became more favorable to the soil mesofauna Therefore, the species richness, abundance and diversity of soil mesofauna in

  2. A dated phylogeny and collection records reveal repeated biome shifts in the African genus Coccinia (Cucurbitaceae

    Directory of Open Access Journals (Sweden)

    Renner Susanne S

    2011-01-01

    Full Text Available Abstract Background Conservatism in climatic tolerance may limit geographic range expansion and should enhance the effects of habitat fragmentation on population subdivision. Here we study the effects of historical climate change, and the associated habitat fragmentation, on diversification in the mostly sub-Saharan cucurbit genus Coccinia, which has 27 species in a broad range of biota from semi-arid habitats to mist forests. Species limits were inferred from morphology, and nuclear and plastid DNA sequence data, using multiple individuals for the widespread species. Climatic tolerances were assessed from the occurrences of 1189 geo-referenced collections and WorldClim variables. Results Nuclear and plastid gene trees included 35 or 65 accessions, representing up to 25 species. The data revealed four species groups, one in southern Africa, one in Central and West African rain forest, one widespread but absent from Central and West African rain forest, and one that occurs from East Africa to southern Africa. A few individuals are differently placed in the plastid and nuclear (LFY trees or contain two ITS sequence types, indicating hybridization. A molecular clock suggests that the diversification of Coccinia began about 6.9 Ma ago, with most of the extant species diversity dating to the Pliocene. Ancestral biome reconstruction reveals six switches between semi-arid habitats, woodland, and forest, and members of several species pairs differ significantly in their tolerance of different precipitation regimes. Conclusions The most surprising findings of this study are the frequent biome shifts (in a relatively small clade over just 6 - 7 million years and the limited diversification during and since the Pleistocene. Pleistocene climate oscillations may have been too rapid or too shallow for full reproductive barriers to develop among fragmented populations of Coccinia, which would explain the apparently still ongoing hybridization between certain

  3. Effects of using kaolin waste and granite waste as raw materials for the production of low-water absorption ceramic tiles; Efeitos da co-utilizacao dos residuos do beneficiamento do caulim e da extracao do granito rain forest para a producao de revestimentos ceramicos com baixa absorcao de agua

    Energy Technology Data Exchange (ETDEWEB)

    Freires, H.P.; Argonz, R.; Nogueira, R.E.F.Q.; Sasaki, J.M., E-mail: argonz@ufc.br [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil); Sales, J.C. [Universidade do Vale do Aracau (UVA), Crateus, CE (Brazil)

    2012-07-01

    This study aims to evaluate the potential of co-use of granite waste (Rain Forest) and kaolin waste as raw material for the manufacture of ceramic coating of low water absorption. Raw materials were characterized by X-ray diffraction. Kaolin residue was added to the residue of granite in the following proportions (in wt%): 0, 10, 20, 30, 40 and 50%. Specimens were fabricated by uniaxial pressing and fired at 1175,1200 and 1225 deg C. Studies of firing linear shrinkage, water absorption, apparent porosity, apparent density and tensile bending test (or rupture modulus) were conducted. The temperature of 1225 deg C allowed the use of a mixture of 50% granite residue and 50% kaolin residue. Ceramic parts made from that mixture exhibited the maximum values required by the Brazilian Standard NBR 13818 for water absorption, shrinkage and density. (author)

  4. Music after the rain

    CERN Multimedia

    2006-01-01

    The group Home Cooking (left to right: Jean-Marie Planche, Tony Arnold, Serge Waeffler, Django Manglunki) entertains the crowd with a humoristic blues/rock performance. The earth moved in Prévessin on 29 July. This was not an earthquake but an 'international' music event, the seventeenth CERN Hardronic Festival, which saw musicians from many different countries, including Russia, Britain, Spain, France, Belgium and the USA, take to the stage. The audience rocked to music from eight different groups until the early hours. About a thousand people flocked to CERN to hear what the best of its musical talents had to offer. The evening was very nearly a wash-out, though. After a week of scorching hot temperatures, the heavens suddenly opened and the rain didn't stop until a few minutes before the first act came on stage. Thanks to this narrow escape, the organisers can boast a 17-year run of rain-free Hardronic festivals. All the different musical styles were given a warm reception, from traditional Russian folk...

  5. Effects of Freezing Rain and Snow Disaster on the Plant Diversity in the Subtropical Evergreen Broad-leaved Forest%雨雪冰冻灾害干扰对亚热带常绿阔叶林植物多样性的影响

    Institute of Scientific and Technical Information of China (English)

    刘足根; 袁小兰; 钟梁; 李铭书

    2014-01-01

    2008年雨雪冰冻灾害后,在崇义县选取了4块亚热带常绿阔叶林作为固定样地,分别记为P1,P2,P3和P4,连续5年监测了雨雪冰冻灾害对其植物多样性的影响。结果表明:雨雪冰冻灾害后的5年内,样地内的马尾松、拟赤杨和桤木消失了,增加了杜英;每块样地重要值排第一的树种在雨雪冰冻灾害后,其重要值都减小了,这些树种主要有槠树、栲树和木荷。雨雪冰冻灾害后,乔木层植物丰富度指数P 1和P3样地增大, P4样地减小, P2样地变化较小;植物多样性指数P1样地增大,P2和P3样地变化较小,P4样地减小;植物均匀度指数P1样地增大,P2和P3样地基本未变,P4样地变化较小。林下植物种类数增加了黄瑞木、猕猴桃、白背叶等植物,而黄杨、野甘菊、苦竹等植物消失了,铁芒萁和茅草数量增加较多。从2011年开始,林内郁闭度恢复到了灾害前水平。%After freezing rain and snow disaster in 2008,four fixed sample plots (P1、P2、P3 and P4) were selected to measure the effects on the plant diversity of the subtropical evergreen broad-leaved for-est in Chongyi County from 2008 to 2012.The result showed that Pinus massoniana,Alniphyllum fortunei and Alnus cremastogyne disappeared,and Elaeocarpus decipiens appeared.The important value of tree species which ranked the first before freezing rain and snow disaster was reduced.These tree species in-cluded Oachestnut,castanopsis fargesii,and Schima superba.The important value of Choerospondias axil-laris increased within five years after the freezing rain and snow disaster.P1 and P2 increased,P4 re-duced,P3 changed little for the Margalef index of the arbor layer.P1 increased,P2 and P3 changed lit-tle,P4 reduced for the Shannon-wiener index of the arbor layer.P1 increased,P2 and P3 basically un-changed,P4 reduced for the Pielou index of the arbor layer.The species kinds and the species number increased

  6. I like riding my bike. If it doesn't rain of course'. Accounts of embodied practices of rain in the face of climate change

    DEFF Research Database (Denmark)

    Lindegaard, Laura Bang

    that whereas cycling is treated as a morally superior practice, rain is treated as a phenomenon that mitigates the normative call to carry it out. The paper argues that this underlines the importance of acknowledging the normative affordances of embodied practices of weather in studies focusing on behavioural......The paper reports on an ethnomethodologically informed study of the discursive accomplishment of everyday transportation practices in the face of climate change. Drawing upon focus group data, the paper shows and discusses the implications of how embodied everyday practices of rain...... are conceptualised. Firstly, the paper focuses on how different practices are conceptualised as related to the embodied practice of rain. Whereas rain is treated as a potential element of the practice of walking in the forest, it is treated as an obstacle to cycling. Thus, even though it is the same rain...

  7. The Rain Keeps Falling

    Directory of Open Access Journals (Sweden)

    Deborah Rose

    2013-08-01

    Full Text Available The force of disaster hit me in the heart when, as a young woman, I heard Bob Dylan sing ‘Hard Rain’. In a voice stunned by violence, the young man reports on a multitude of forces that drag the world into catastrophe. In the 1960s I heard the social justice in the song. In 2004 the environmental issues ambush me. The song starts and ends in the dying world of trees and rivers. The poet’s words in both domains of justice are eerily prophetic. They call across the music, and across the years, saying that a hard rain is coming. The words bear no story at all; they give us a series of compelling images, an account of impending calamity. The artistry of the poet—Bob (Billy Boy Dylan—offers sequences of reports that, like Walter Benjamin’s storm from paradise, pile wreckage upon wreckage.

  8. Dust Rains Deliver Diverse Assemblages of Microorganisms to the Eastern Mediterranean

    Science.gov (United States)

    Itani, Ghida Nouhad; Smith, Colin Andrew

    2016-03-01

    Dust rains may be particularly effective at delivering microorganisms, yet their biodiversities have been seldom examined. During 2011 and 2012 in Beirut, Lebanon, 16 of 21 collected rainfalls appeared dusty. Trajectory modelling of air mass origins was consistent with North African sources and at least one Southwest Asian source. As much as ~4 g particulate matter, ~20 μg DNA, and 50 million colony forming units were found deposited per square meter during rainfalls each lasting less than one day. Sequencing of 93 bacteria and 25 fungi cultured from rain samples revealed diverse bacterial phyla, both Gram positive and negative, and Ascomycota fungi. Denaturing Gradient Gel Electrophoresis of amplified 16S rDNA of 13 rains revealed distinct and diverse assemblages of bacteria. Dust rain 16S libraries yielded 131 sequences matching, in decreasing order of abundance, Betaproteobacteria, Alphaproteobacteria, Firmicutes, Actinobacteria, Bacteroidetes, Cyanobacteria, Epsilonproteobacteria, Gammaproteobacteria, and Deltaproteobacteria. Clean rain 16S libraries yielded 33 sequences matching only Betaproteobacteria family Oxalobacteraceae. Microbial composition varied between dust rains, and more diverse and different microbes were found in dust rains than clean rains. These results show that dust rains deliver diverse communities of microorganisms that may be complex products of revived desert soil species and fertilized cloud species.

  9. Acid Rain Limits Global Warming

    Institute of Scientific and Technical Information of China (English)

    Will Knight; 张林玲

    2004-01-01

    @@ Acid rain restricts global warming by reducing methane① emissions from natural wetland areas, suggests a global climate study. Acid rain is the result of industrial pollution,which causes rainwater to carry small quantities of acidic compoumds② such as sulphuric and nitric acid③. Contaminated rainwater can upset rivers and lakes, killing fish and other organisms and also damage plants, trees and buildings.

  10. Acid Rain: The Scientific Challenge.

    Science.gov (United States)

    Godfrey, Paul J.

    1991-01-01

    Documents the workings and findings of the Massachusetts Acid Rain Monitoring Project, which has pooled the volunteer efforts of more than 1,000 amateur and professional scientists since 1983. Reports on the origins of air pollution, the prediction of acid rain, and its effects on both water life and land resources. (JJK)

  11. Acid Rain: What's the Forecast?

    Science.gov (United States)

    Bybee, Rodger

    1984-01-01

    Discusses various types of acid rain, considered to be a century-old problem. Topics include: wet and dry deposition, effects on a variety of environments, ecosystems subject to detrimental effects, and possible solutions to the problem. A list of recommended resources on acid rain is provided. (BC)

  12. Carbon, nitrogen cycling and land cover changes during regrowth in African dry tropical forests: integrating perspectives from field and satellite data across a chronosequence in the Miombo Woodlands of western Tanzania

    Science.gov (United States)

    Mayes, M. T.; Melillo, J. M.; Mustard, J. F.; Neill, C.; Nyadzi, G.

    2015-12-01

    Seasonally dry tropical forests in Africa (SDTFs), such as forests in Miombo Woodlands, are experiencing high rates of deforestation, degradation and regrowth. Increasing proportions of forest are disturbed or composed of young regrowth stands (soil mineral N availability with regrowth; (2) How does N demand for tree leaf production compare to indicators of available mineral N in surface soils from young to mature forest sites; (3) How does canopy structure vary with regrowth and disturbance and scale to Landsat-style satellite data? We established a chronosequence of 18 sites with ages 3 to >40 years since abandonment. At each, we inventoried trees to quantify aboveground tree C stocks, sampled soils to 100 cm to measure C, total and mineral N (NH4+, NO3-), and surveyed canopy cover with point-line transects, spherical densiometer and photometric leaf area measures. We also conducted soil incubations to determine nitrogen mineralization potentials. Tree C stocks ranged from 0.4 ± 0.1 Mg C ha-1 for 3-4 year sites to 27.2 ± 5.2 Mg C ha-1 for 30-40 year sites, and were 44.5 ± 7.4 Mg C ha-1 for mature forest sites. Rates of aboveground tree C stock changes (0.78 - 0.89 Mg C ha-1 yr-1) were comparable to the few published for Miombo forests. However, tree C stocks at 10 - 24 year sites (5.2 ± 1.1 Mg C ha -1) were much lower than those reported in comparable studies. Only sites > 30-40 years had C stocks approaching mature forests. Further analyses will compare N dynamics from leaves and soil across the chronosequence, and relate them to the trends in tree C stocks. We use ground and canopy cover data to test remote sensing characterizations of land cover across disturbed and regrowth sites. Such scaling relationships will allow us to improve remote sensing characterization of land cover in African SDTFs and develop landscape-scale estimates of how forest cover changes affect C, N and water cycling regionally.

  13. 吊罗山国家森林公园热带雨林不同恢复阶段群落结构与生物多样性比较研究%Comparative Study on the Community Structure and Biodiversity of Tropical Rain Forest at Different Restoration Stages in Diaoluo Mountain National Forest Park

    Institute of Scientific and Technical Information of China (English)

    殷云翰

    2013-01-01

    By the methods of community structure analysis,forest resources monitoring and biodiversity analysis,tropical rain forest plots at 3 different recovery stages in Diaoluo Mountain National Forest Park of Hainan province were investigated.The 3 plots located in tropical rainforest restored in 1960s,tropical rainforest restored in 1970s,and virgin rainforest respectively and were with the same area.From the starting point of dominant species of community,the variation of characteristics of community structure and species composition,plant species richness and diversity of the 3 plots were discussed.Results showed that with the process of time,the difference of dominant species in the 3 plots was increasing.The average tree height and clear bole height of arbor in the rainforest plot restored in 1970s were higher than that in the other 2 plots.The DBH (diameter at breast height) of virgin rainforest trees was greater than that of the other 2 plots.Comparatively,the species richness was the biggest in virgin rainforest,while was equal in rainforest restored in 1960s,and rainforest restored in 1970s; the species diversity index and evenness index of the virgin rainforest was the biggest; and ecological dominance was similar with that of the other 2 plots,thus the biodiversity of virgin rainforest was the highest.The biodiversity indexes of rainforest restored in 1970s were greater than those of rainforest restored in 1960s,so its biodiversity was higher than that of rainforest restored in 1960s.Overall,the species richness and biodiversity of the 3 plots was with little difference.%采用植物群落结构分析、森林资源监测及生物多样性分析方法,对海南省吊罗山国家森林公园3个不同恢复阶段的热带雨林样地进行调查研究,3个样地分别位于20世纪60年代恢复的热带雨林、70年代恢复的热带雨林、原始热带雨林内,样地面积一致.以群落的优势种为出发点,探讨了3个样地的群落种类组成与

  14. [Relationship between simulated acid rain stress and leaf reflectance].

    Science.gov (United States)

    Song, Xiao-dong; Jiang, Hong; Yu, Shu-quan; Zhou, Guo-mo; Jiang, Zi-shan

    2010-01-01

    Acid rain is a worldwide environmental problem. Serious acid rain pollution in subtropical China has constituted a potential threat to the health of the local forest. In the present paper, the changing properties of the chlorophyll concentration and spectral reflectance at the visible wavelengths for the six subtropical broad-leaved tree species leaves under simulated acid rain (SAR) treatment with different pH levels were studied. With the increasing strength of the SAR, the chlorophyll concentrations of the experimental species under pH 2.5 and pH 4.0 treatment were higher than that under pH 5.6; the spectral reflectance at the visible wavelengths for pH 2.5 and pH 4.0 were lower than that for pH 5.6 in general; while there weren't significant differences between pH 2.5 and pH 4.0. After the treatment with different levels of SAR, the differences in spectral reflectance at the visible wavelengths mainly focused around the green peak and red edge on the reflectance curve. The subtropical broad-leaved tree species studied were relatively not sensitive to acid rain stresses; some stronger acid rain may accelerate the growth of the tree species used here to some extent.

  15. Caracterização fisionômica - estrutural de um remanescente de floresta ombrófila montana de Pernambuco, Brasil Physiognomic and structural characterization of a montane rain forest remnant in Pernambuco State, Brazil

    Directory of Open Access Journals (Sweden)

    Elba Maria Nogueira Ferraz

    2006-12-01

    Full Text Available As florestas ombrófilas montanas de Pernambuco são pouco estudadas quanto a fisionomia, florística, estrutura e semelhanças com as florestas de terras baixas. Visando este entendimento, foi realizada a caracterização fisionômica-estrutural do maior remanescente (São Vicente Férrer, 600 ha dessa floresta no Estado e sua comparação com outras florestas ombrófilas nordestinas de terras baixas e montanas. A área estudada localiza-se na encosta oriental do planalto da Borborema (07º38' S e 35º30' W, em altitudes entre 600 e 640 m, e tem precipitação média anual de 1.103 mm. Foram alocadas 50 parcelas de 10×20 m e incluídos os indivíduos com DAP > 5 cm. Os 1.521 indivíduos amostrados pertenceram a 58 famílias, 96 gêneros e 152 espécies. Cerca de 50% deles tiveram altura entre 6,1 e 12,0 m e diâmetro entre 5 e 10 cm, sendo representados, predominantemente, por Clusiaceae, Quiinaceae, Myrtaceae e Sapindaceae. As famílias de maior valor de importância (Myrtaceae, Clusiaceae, Moraceae, Mimosaceae, Caesalpiniaceae, Vochysiaceae, Myristicaceae, Elaeocarpaceae, Lecythidaceae e Anacardiaceae foram dominantes em diferentes classes de altura, tiveram número de espécies variado (1 a 10 e, geralmente, as maiores densidades. A floresta estudada foi melhor relacionada em composição de espécies e famílias com as florestas de terras baixas, embora tenha se destacado pela elevada riqueza de taxa, maior altura e principalmente pela abundância de famílias e espécies pouco comuns às florestas ombrófilas de terras baixas de Pernambuco.The montane forests of Pernambuco, Brazil, are poorly understood in relation to their flora, physiognomy, structure, and similarity to lowland forests. The physiognomy and structure of the largest ombrophilous forest fragment in the state of Pernambuco (São Vicente Ferrer, 600 ha were described and compared with other montane and lowland forests in northeastern Brazil. The study site is located on the

  16. Structural characteristics of rain fields

    Science.gov (United States)

    Mesnard, FréDéRic; Sauvageot, Henri

    2003-07-01

    This paper analyzes the shape of rain area size distributions (RASDs) observed by radar in tropical and midlatitude regions. The rain area is defined, with respect to a rain threshold τ, as the area, inside a contour, where the rain rate is higher than τ. The size considered is the diameter of the equivalent circular area D. The reflectivity peaks inside the rain areas are numbered and the rain areas put together by classes having the same peak number. The size distributions of the rain areas containing the same number of peaks p are well fitted by lognormal functions, the parameters of which, μp and σp, are weakly dependent on the conditions of the peak determination. The parameters μp and σp are found to be linked by a power relation. For D RASD without peak number distinction is a lognormal mixture. Using the relations obtained for μp, σp, and the rain area number as functions of p enables one to simulate RASDs with results in good agreement with the observations. Because of the limitation in the radar sampling at both ends of the RASD and the decrease of area number with increasing size, the radar-observed RASDs are severely truncated. The possibility of an approximate fitting of the truncated RASD with diverse functions is discussed. At the intermediary values of the threshold, i.e., for τ ranging between 3 and 12 mm h-1, where the RASD is easiest to compute, the slope of these truncated distributions is not strongly dependent on the threshold. This slope appears not to be very sensitive to the minimum and maximum distances bounding the domain where the rain field is observed. The RASD is found to be sloping more over sea than over land. The slope of the RASDs shows a small diurnal variation but no significant annual variation. The "perimeter to area" (fractal) dimension of the rain area for the sample without peak number distinction is around 1.35. Single-peaked and multipeaked rain areas have different perimeter to area dimensions, ˜1.23 and 1

  17. DINÁMICA DE LA BIOMASA AÉREA EN UN BOSQUE PLUVIAL TROPICAL DEL CHOCÓ BIOGEOGRÁFICO DYNAMICS OF TREE ABOVEGROUND BIOMASS IN A TROPICAL RAIN FOREST OF THE CHOCÓ BIOGEOGRÁFICO

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    Harley Quinto Mosquera

    2011-06-01

    Full Text Available El estudio de la biomasa aérea (BA de los bosques tropicales es fundamental para entender el balance del C global en el contexto del cambio climático. La BA se cuantificó en un bosque maduro de Salero (Chocó Biogeográfico, mediante ecuaciones diseñadas para bosques húmedos tropicales, a partir de datos de densidad de madera, diámetro (DAP y altura de árboles (con DAP = 10 cm medidos en dos sub-parcelas permanentes ("E" y "U" de 1 ha, las cuales se monitorearon en los años 1998, 2005 y 2008. La BA fue 237,31 t·ha-1, 259,99 t·ha-1 y 217,97 t·ha-1 respectivamente en la sub-parcela "E". Mientras que en la "U" fue de 178,94 t·ha-1y 179,17 t·ha-1 en los años 2005 y 2008; las diferencias de BA a través del tiempo fueron no significativas. Los incrementos promedios anuales de BA de sobrevivientes fueron 4,42 y 3,18 t·ha-1 año-1 en las sub-parcelas "E" y "U" respectivamente. Además, en sub-parcela "E" en condiciones imperturbadas, se presentó una tasa de incremento neto de la BA (TINBA de 2,61 t·ha-1 año-1, en concordancia con la hipótesis del incremento en la BA en los bosques húmedos tropicales. La productividad primaria neta aérea (PPNA en Salero de carbono fue de 5,21 t· ha-1 año-1, por lo tanto los resultados no apoyaron la hipótesis de la disminución en la productividad de los bosques tropicales con el incremento en la precipitación.The study of the aboveground biomass (AB of tropical forests is fundamental to understand the balance of the global C in the context of the climatic change. We quantified the AB in a mature forest of Salero (Chocó Biogeográfico, by means of equations designed for tropical humid forests, starting from data of wooden density, diameter (D and height of trees (with D = 10 cm measured in two permanent sub-parcels (E and U of 1 hectare (ha, which were measured in the years 1998, 2005 and 2008. Inthis years the AB was of 237.31 t·ha-1, 259.99 t·ha-1 and 217.97 t·ha-1 respectively in the E

  18. Análise discriminante de solos sob diferentes usos em área de Mata Atlântica a partir de atributos da matéria orgânica Discriminant analysis of soils under different land uses in the Atlantic Rain Forest area using organic matter attributes

    Directory of Open Access Journals (Sweden)

    Vinicius de Melo Benites

    2010-08-01

    Full Text Available Na região serrana do Estado do Rio de Janeiro (bioma Mata Atlântica, pequenos agricultores praticam agricultura itinerante no sistema de corte e queima. Neste trabalho, amostras de horizontes superficiais (0 -15 cm de um Latossolo Vermelho-Amarelo sob cinco diferentes coberturas vegetais (Mata Atlântica, cultivo anual, café, banana e pastagem foram coletadas para caracterização química dos teores de carbono nas diferentes frações de substâncias húmicas. As amostras obtidas sob mata e sob pastagem puderam ser nitidamente isoladas das demais pelo modelo discriminante construído. Aquelas representativas do grupo das culturas (banana, café e cultivo foram superposicionadas, indicando haver semelhança entre os atributos relativos à matéria orgânica nos solos sob esses usos. O modelo obtido permitiu classificar corretamente 88% das amostras analisadas. Os atributos ácidos fúlvicos (AF, carbono orgânico (C, nitrogênio total (N e relação C/N foram selecionados pelo modelo, sendo o teor de ácidos fúlvicos o atributo de maior peso relativo. Esse resultado indica que o fracionamento de substâncias húmicas permite a observação de alterações no solo que não são possíveis de serem identificadas pela simples determinação do teor de carbono orgânico total. Pelo padrão de agrupamento das áreas (mata-pastagem e banana-café-cultivo, denotou-se que o uso de fertilizantes pode se relacionar com alterações em atributos indicadores importantes, como o teor de ácidos fúlvicos.In the mountain region of the State of Rio de Janeiro (Atlantic Rain Forest biome, small farmers practice shifting cultivation in the slash and burn system. In this work, soil surfaces samples (0-15cm of a Yellow Red Latossolo under five different vegetal coverings (Atlantic Rain Forest, annual culture, coffee, banana and pasture, had been taken in the small farming area of Bom Jardim RJ for soil chemical characterization and carbon content analysis in

  19. Tempered by Winds and Rains of Nature

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    A few years ago, a popular TV program Animal World produced by China Central Television (CCTV), was well received by men and women, old and young, and people from all circles. Sun Qiuping, a reporter from CCTV, led her colleagues to film the section about wild animals in China.For six years, Sun and her colleagues sought those nearly extinct wild animals in the virgin forests and barren hills. They experienced many hardships, and even the trial of death.In 1992, Sun won first prize in the First National TV Program Contest for her first TV program Oasis in the Mist about the tropical rain forest and its wild life. She also won awards for photography and music. Sun edited the TV program Mongoose and won a first prize for programs on special topics. Because of her accomplishments, she has been awarded the prize of the CCTV director’s special fund, and was named a national "March 8 Pacesetter’ by the All-China Women’s Federation.

  20. Economic valuation of forests and nature : a support tool for effective decision making

    NARCIS (Netherlands)

    Lette, H.; Boo, de H.

    2002-01-01

    Included are several case studies, like: The Leuser ecosystem, Sumatra; The Borivili National Park, India; Tropical rain forests, Costa Rica; Mangrove forests, Philippines. This document has been prepared by: IAC and EC-LNV

  1. Taxonomy and distribution pattern of the African rain forest butterfly genus Euphaedra Hübner sensu stricto with the description of three new subspecies of Euphaedra cyparissa (Cramer and one of E. sarcoptera (Butler (Lepidoptera, Nymphalidae, Limenitidinae, Adoliadini

    Directory of Open Access Journals (Sweden)

    Tomasz Pyrcz

    2013-05-01

    Full Text Available Updated data on the distribution, ecology and taxonomy of Euphaedra cyparissa (Cramer and Euphaedra sarcoptera (Butler are presented. Three new subspecies of E. cyparissa and one of E. sarcoptera are described and their geographic distribution is presented. The monophyly of the genus Euphaedra sensu Hecq is assessed based on morphological, in particular male and female genitalia, and behavioural traits. Possible evolutionary reasons for the convergence of colour pattern between the sympatric subspecies of E. cyparissa and E. sarcoptera are discussed.

  2. DIVERSIDAD DE ORQUÍDEAS EPÍFITAS EN UN BOSQUE HÚMEDO TROPICAL (BH-TDEL DEPARTAMENTO DEL CHOCÓ, COLOMBIA. Diversity of Orchids Epiphytes in a Tropical Rain Forest (Bh-Tof Departament Chocó, Colombia.

    Directory of Open Access Journals (Sweden)

    HEIDY MEJÍA ROSERO

    Full Text Available Se evaluó la diversidad de orquídeas epífitas en un bosque húmedo tropical (bh-T, perteneciente al corregimiento de Tutunendo (Quibdó. En él fueron establecidas tres zonas de acuerdo al grado de intervención del bosque: poco (300 m², medio (400 m² y altamente intervenido (300 m²; dentro de estos fueron registrados 66 forófitos con un DAP ≥a 20 cm, en los cuales se muestrearon las orquídeas huéspedes, obteniendo un registro total de 1.348 individuos, distribuidos en 49 especies y 20 géneros. Los géneros más representativos en número de especies fueron Maxillaria (11 y Dichaea (5. Según el índice de Shannon-Weiner, se aprecia una alta diversidad de orquídeas epífitas en el área de estudio (H’=3,30. En cuanto a las zonas de acuerdo al grado de intervención, el bosque medio y el poco intervenido fueron los más altos en diversidad, sin embargo, el altamente intervenido, donde se da el tipo de cultivo de tumba y siembra y la extracción maderera es constante, presentó los más bajos resultados. Según la prueba de Kruskal-Wallis, estas zonas presentaron diferencias significativas (PThe diversity of epiphytes orchids in a tropical humid forest of the municipality of Tutunendo (Quibdó was evaluated. According to its level of intervention, it was established three zones in the forest: low (300 m², medium (400 m² and highly intervened (300 m²; 66 forófitos with a DAP ≥20 cm were recorded, in which orchids guests were sampled giving a total record of 1348 specimens, distributed in 49 species and 20 genera. In terms of number of species, the most representative genera were Maxillaria (11 and Dichaea (5. According to the Shannon-Weiner index a high diversity of epiphytes orchids can be observed in the area of study (H‘= 3.30. Regarding to areas according to the level of intervention, the low and medium intervened forest showed the highest diversity, however, the highly intervened, where tomb cultivation, sowing logging

  3. African Literature

    OpenAIRE

    Recek, Denis

    2011-01-01

    The topic of this diploma is the formation and shaping of African literature. The first chapter is about the beginning of African literature. It describes oral literature and its transmission into written literature. Written African literature had great problems in becoming a part of world literature because of its diversity of languages and dialects. Christianity and Islam are mentioned as two religions which had a great impact on African literature. Colonialism is broadly described as an es...

  4. Benefiting Africans

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Along with thriving Sino-African economic and trade ties,Chinese companies have attached greater importance to their social responsibility to Africans.More than 2,000 sweaters woven by Chinese mothers were sent to orphans and disabled children in Kenya and four other African countries in September. This activity was launched by Hengyuanxiang,aleading Chinese wool manufacturer.

  5. Benefiting Africans

    Institute of Scientific and Technical Information of China (English)

    ZHANG ZHIPING

    2011-01-01

    Along with thriving Sino-African economic and trade ties,Chinese companies have attached greater importance to their social responsibility to Africans.More than 2,000 sweaters woven by Chinese mothers were sent to orphans and disabled children in Kenya and four other African countries in September.This activity was launched by Hengyuanxiang,a leading Chinese wool manufacturer.

  6. Correlates of microhabitat use and density of Clethrionomys gapperi and Peromyscus keeni in temperate rain forests of Southeast Alaska%阿拉斯加东南部温带雨林加氏(鼠平)和肯氏鹿鼠密度与微生境利用的相关性

    Institute of Scientific and Technical Information of China (English)

    Winston P. SMITH; Scott M. GENDE; Jeffrey V. NICHOLS

    2005-01-01

    为了验证对阿拉斯加东南部温带雨林中有关栖息地关系的预测,我们于1999年和2000年8-9月以及1999年和2000年4-5月研究了亚历山大群岛加氏(鼠平)(Clethrionomys gapperi)和肯氏鹿鼠(Peromyscus keeni)种群.我们测量了26个植被和结构特征以检验林隙老龄生长林、多时代老龄生长林、采伐前壮龄(23岁)生长林和泥炭混交针叶林的丰富度与微栖息地利用的相关性.微栖息地利用随季节和栖息地而变化,但加氏(鼠平)与林下落叶灌木覆盖度的正相关最显著.肯氏鹿鼠利用的微环境的林地有较少的苔藓,但是林隙与抓获加氏(鼠平)的概率有直接关系.两种鼠在两个季节的密度与林下腐朽的倒木直接相关.春季的肯氏鹿鼠密度说明加氏(鼠平)密度变化的62%,说明肯氏鹿鼠密度变化的89%.我们的结果印证了早期对阿拉斯加东南部肯氏鹿鼠在各种栖息地尤其早期的演替林中兴旺时的研究;但偏离了西部地貌中肯氏鹿鼠种群在晚期演替针叶林中达到最高密度的普遍结论.与北美西北部其它地区的种群不同,加氏(鼠平)能持久生活在上层被砍伐的雨林板块中.泥炭针叶混交林对两种鼠的繁殖种群几乎没有贡献,因而不可能减轻对多产的老龄生长雨林大规模皆伐所造成的影响.%We studied red-backed vole Clethrionomys gapperi and Keen's mouse Peromyscus keeni populations in the Alexander Archipelago to test predictions regarding habitat relations in temperate rain forest of southeastern Alaska during August-September 1998 and 2000 and April-May 1999 and 2000. We measured 26 vegetative and structural features to correlate abundance among and microhabitat use within gap-phase old growth, multi-cohort old growth, pre-commercially thinned young (23-yr-old) growth, and peatland mixed-conifer forests. Populations of both species were higher in 1998 than 1999 and 2000. Both species used microhabitats randomly in

  7. Asian irrigation, African rain: Remote impacts of irrigation

    Science.gov (United States)

    Vrese, Philipp; Hagemann, Stefan; Claussen, Martin

    2016-04-01

    Irrigation is not only vital for global food security but also constitutes an anthropogenic land use change, known to have strong effects on local hydrological and energy cycles. Using the Max Planck Institute for Meteorology's Earth System Model, we show that related impacts are not confined regionally but that possibly as much as 40% of the present-day precipitation in some of the arid regions in Eastern Africa are related to irrigation-based agriculture in Asia. Irrigation in South Asia also substantially influences the climate throughout Southeast Asia and China via the advection of water vapor and by altering the Asian monsoon. The simulated impact of irrigation on remote regions is sensitive to the magnitude of the irrigation-induced moisture flux. Therefore, it is likely that a future extension or decline of irrigated areas due to increasing food demand or declining fresh water resources will also affect precipitation and temperatures in remote regions.

  8. Importância das bromélias epífitas na ciclagem de nutrientes da Floresta Atlântica The importance of epiphytic bromeliads on the turnover of nutrients at the Atlantic Rain Forest

    Directory of Open Access Journals (Sweden)

    Rogério Ribeiro de Oliveira

    2004-12-01

    Full Text Available O material epifítico pode ser considerado como importante fonte de nutrientes para florestas localizadas em solos pobres. O presente trabalho foi realizado em um trecho de Floresta Atlântica com características primárias localizado no Pico do Papagaio, Ilha Grande, RJ. Pelo período de um ano, a serapilheira total e a produzida por bromélias epífitas foram coletadas por meio de diferentes coletores (16 de 0,25m² para serapilheira total e 10 de 25m² para a de bromélias. Alíquotas completas do material coletado foram usadas para determinação dos teores de N, P, K, Na, Ca e Mg em espectrofotometria de absorção atômica. Ao longo de um ano, a produção de serapilheira oriunda de bromélias foi de 327,8 kg/ha, o que representou 3,1% da serapilheira total produzida no mesmo período (10.690,9kg/ha. A contribuição da serapilheira de bromélias apresentou distribuição espacial irregular em relação à da serapilheira total. Em relação ao fluxo destes nutrientes, as maiores participações foram Na (4,4kg/ha/ano; K (7,6kg/ha/ano e Mg (7,0kg/ha/ano, o que correspondeu, respectivamente, a 27,5, 18,7 e 13,9% dos aportes feitos pela serapilheira em geral. Esta participação ocorreu em função da concentração relativamente elevada destes nutrientes na serapilheira de bromélias.Epiphytic material can be considered an important source of nutrients for forests found on poor soils. This work was done in a tract of a primary Atlantic Forest with located in the Pico do Papagaio, Ilha Grande, RJ, Brazil. Over a year, the total litter and that produced by epiphytic bromeliads were collected by different ways (16 of 0.25m² for total litter and 10 of 25m² for that of bromeliads. Complete aliquots of matter collected were used to determine the composition of N, P, K, Na, Ca and Mg with atomic absorption spectrophotometer. During one year, litter production of bromeliads was of 327.8kg/ha, which represented 3.1% of total litter produced in

  9. The urban perspectives of acid rain. Workshop summary

    Energy Technology Data Exchange (ETDEWEB)

    Tonn, B.E.

    1993-06-04

    This report documents discussions held during a workshop an Urban Perspective of Acid Rain. The workshop was sponsored by the Office of the Director, National Acid Precipitation Assessment Program (NAPAP). NAPAP anticipates giving increased emphasis to the benefits in urban areas of emissions reductions. The goal of this informal, exploratory workshop was to serve as a first step towards identifying pollutant monitoring, and research and assessment needs to help answer, from an urban perspective, the two key questions posed to NAPAP by Congress: (1) what are the costs, benefits, and effectiveness of the acid rain control program, and (2) what reductions in deposition, rates are needed in order to prevent adverse effects? The workshop addressed research activities needed to respond to these questions. The discussions focused. sequentially, on data needs, data and model availability, and data and modeling gaps. The discussions concentrated on four areas of effects: human health, materials, urban forests, and visibility.

  10. Carbon sink potential of multistrata agroforestry systems at Atlantic Rain Forest Potencial de sistemas agroflorestais multiestrata para sequestro de carbono em áreas de ocorrência de Floresta Atlântica

    Directory of Open Access Journals (Sweden)

    Luís Cláudio Maranhão Froufe

    2011-06-01

    Full Text Available

    Carbon storage of agroforestry systems, regenerated areas, conventional agriculture and pasture was evaluated at Alto Ribeira Valley region, São Paulo State, Brazil, in different compartments of Land-use systems (LUS. In soil, classified as Entisols and Inceptisols, we found similarities among all LUS, dued to their low contents of organic carbon, and similar values of bulk density. The total carbon stocked on land-use systems, greater amounts were determined on regenerated areas (115.78 Mg ha-1, followed by agroforestry systems (75.38 Mg ha-1, agriculture (47.07 Mg ha-1, and pasture (36.01 Mg ha-1. Despite their conservative characteristic, the silvicultural practices of multistrata agroforestry systems have to be improved for forest production and carbon sequestration.

    doi: 10.4336/2011.pfb.31.66.143

    Foi avaliado o estoque de carbono no solo, serapilheira, biomassa arbórea e biomassa herbácea de SAFs multiestratos, em comparação a capoeiras em diferentes estágios de regeneração, sistemas agrícolas convencionais e pastagem, todos na região do Alto Vale do Ribeira, SP. Nos Neossolos e Cambissolos, com baixos teores de carbono orgânico e similaridade dos valores de densidade aparente, as capoeiras contribuíram com 115,78 Mg ha-1 de carbono total estocado, seguidas dos SAFs (75,37 Mg ha-1, das áreas agrícolas (47,07 Mg ha-1 e das pastagens (36,01 Mg ha-1. Apesar do grande potencial de sequestro de carbono dos SAFs, há necessidade de melhoria em suas práticas silviculturais.

    doi: 10.4336/2011.pfb.31.66.143

  11. Acid Rain Program Opt-in Factsheet

    Science.gov (United States)

    Learn about the Opt-in Program, which allows sources not required to participate in the Acid Rain Program the opportunity to enter the program on a voluntary basis and receive Acid Rain Program allowances.

  12. Acid Rain: What We Must Do.

    Science.gov (United States)

    Gorham, Eville

    1983-01-01

    Addresses questions about the nature, source, and history of acid rain. In addition, discusses the questions: Why is acid rain a problem? Is acid rain getting worse? What is the threat of further problems? Concludes that it is time to act on the problem and recommends an appropriate course of action. (JN)

  13. Study on the Distribution Patterns and Dynamics of Main Tree Population of Fagaceae Dominance in Tropical Montane Rain Forest in Hainan Island%海南以壳斗科植物为优势的山地雨林主要乔木种群分布格局及动态研究

    Institute of Scientific and Technical Information of China (English)

    吕晓波; 杨立荣; 杨民; 杨小波; 李东海; 陶楚; 万春红

    2012-01-01

    为了了解霸王岭地区以壳斗科植物为优势的山地雨林群落的主要种群的空间分布格局,以及格局的动态变化规律,更好、更全面地管理和保护山地雨林,通过对样地群落中8个主要的乔木种群,采用样方法取样和方差均值比的方法进行检验分析.结果表明,红锥、红椆、肉实树3个种群为随机分布类型,公孙锥、鸭脚木、岭罗麦、黄杞和狭叶泡花5个种群为集群分布类型.反映出群落正处于演替的中期阶段,随着演替的发展,随机分布类型会逐渐上升.各种群的分布格局动态变化过程可分为5种类型:Ⅰ型:红锥、公孙锥和狭叶泡花种群的集群—随机—随机模式;Ⅱ型:鸭脚木种群的集群—集群—随机模式;Ⅲ型:黄杞种群的随机—集群—集群模式;Ⅳ型:肉实树和红椆种群的随机—随机—随机模式;Ⅴ型:岭罗麦为随机—集群—随机,表现出不同种群的生长、发育模式有较大的差异性.%In order to understand the spacial distribution pattern and the dynamic changes of spacial distribution pattern of the major tree species in the Fagaceae dominance in tropical montane rain forest in Hainan island, people will better and roundly manage and protect the montane rain forest. In this plot, there were 8 major tree species. By method of variance/mean, the author found that Castanopsis hystrix, L. Fenzelianus A. Camus and Sarcosperma laurinum were random distribution pattern and Castanopsis tonkinensis, Schefflera octophylla, Tarennoidea wallichii, Engelhardia roxburghiana and Meliosma angustifolia were cluster distribution pattern. By study on change of speices distrbution pattern, the author found that there were 5 change types of different grade species. Castanopsis hystrix, Castanopsis tonkinensis and Meliosma angustifolia belonged to the type Ⅰ of Cluster-Random-Random; Schefflera octophylla belonged to the type Ⅱ of Cluster-Cluster-Random; Engelhardia

  14. Litterfall, precipitation and nutrient fluxes in a secondary lowland rain forest in Ile-Ife, Nigeria Queda de serrapilheira, precipitação e fluxo de nutrientes em uma floresta pluvial secundária de terras baixas em Il-Ife, Nigéria

    Directory of Open Access Journals (Sweden)

    Modupe B. Oziegbe

    2011-09-01

    Full Text Available Litterfall, precipitation and nutrient fluxes were investigated in a 0.25 ha plot of a secondary lowland rain forest in Ile-Ife, Nigeria, for a period of one year. The study determined the magnitude of nutrient fluxes through (litterfall, incident rainfall, throughfall and stemflow and evaluated the relative importance of these components as pathways of nutrient transport to the soil of this forest. There was a significant monthly variation in litterfall and the highest values of the standing crop of litter occurred from November to March. The concentration of elements in both throughfall and stemflow were higher than those of incidence rainfall. Greater quantities of calcium, magnesium, iron, zinc, copper and nitrogen were deposited annually from the forest floor while greater quantities of mercury, potassium, sodium, phosphorus, lead and sulphur were deposited via precipitation. There was net leaching of all elements from the canopy as precipitation pass through it with the exception of copper, hydrogen ions and lead, which were retained in the canopy. The finding of this study shows that litterfall is the major pathway for the cycling of calcium, magnesium, nitrogen and all micronutrients investigated. Net precipitation is the major pathway for the cycling of potassium, phosphorus, sulphur and trace toxic metals (mercury and lead in the forest.Produção de serapilheira, precipitação e o fluxo de nutrientes foram investigados em uma parcela de 0,25 ha de uma floresta pluvial secundária de terras baixas em Ile-Ife, Nigéria, por um período de um ano. O estudo determinou a magnitude dos fluxos de nutrientes através da serrapilheira, da chuva incidente, da interceptada, da escoada pelo tronco, e também avaliou a importância relativa desses componentes como vias de transporte de nutrientes para o solo desta floresta. Houve variação mensal significativa na produção e acúmulo de serapilheira com maiores valores ocorrendo de novembro a

  15. Global-Scale Patterns of Forest Fragmentation

    Directory of Open Access Journals (Sweden)

    Kurt Riitters

    2000-12-01

    Full Text Available We report an analysis of forest fragmentation based on 1-km resolution land-cover maps for the globe. Measurements in analysis windows from 81 km 2 (9 x 9 pixels, "small" scale to 59,049 km 2 (243 x 243 pixels, "large" scale were used to characterize the fragmentation around each forested pixel. We identified six categories of fragmentation (interior, perforated, edge, transitional, patch, and undetermined from the amount of forest and its occurrence as adjacent forest pixels. Interior forest exists only at relatively small scales; at larger scales, forests are dominated by edge and patch conditions. At the smallest scale, there were significant differences in fragmentation among continents; within continents, there were significant differences among individual forest types. Tropical rain forest fragmentation was most severe in North America and least severe in Europe-Asia. Forest types with a high percentage of perforated conditions were mainly in North America (five types and Europe-Asia (four types, in both temperate and subtropical regions. Transitional and patch conditions were most common in 11 forest types, of which only a few would be considered as "naturally patchy" (e.g., dry woodland. The five forest types with the highest percentage of interior conditions were in North America; in decreasing order, they were cool rain forest, coniferous, conifer boreal, cool mixed, and cool broadleaf.

  16. Wood Properties of Poplar from Stand Affected by Acid Rain

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Wood properties from 28 trees (Populus euramericana) selected from healthy and acid rain damaged forest were measured to evaluate the possible impacts on wood quality and utilization. On the heavily damaged location, the pH value of precipitation ranged from 3.7-5.0, and sulfate loading ranged from 20-40 kg·ha-2.y-1. Quantitative and qualitative studies on ring width, physical properties and mechanical properties indicated that changes of wood properties between diseased and healthy poplar occurred. Aci...

  17. Tropical secondary forest management influences frugivorous bat composition, abundance and fruit consumption in Chiapas, Mexico.

    Science.gov (United States)

    Vleut, Ivar; Levy-Tacher, Samuel Israel; de Boer, Willem Frederik; Galindo-González, Jorge; Vazquez, Luis-Bernardo

    2013-01-01

    Most studies on frugivorous bat assemblages in secondary forests have concentrated on differences among successional stages, and have disregarded the effect of forest management. Secondary forest management practices alter the vegetation structure and fruit availability, important factors associated with differences in frugivorous bat assemblage structure, and fruit consumption and can therefore modify forest succession. Our objective was to elucidate factors (forest structural variables and fruit availability) determining bat diversity, abundance, composition and species-specific abundance of bats in (i) secondary forests managed by Lacandon farmers dominated by Ochroma pyramidale, in (ii) secondary forests without management, and in (iii) mature rain forests in Chiapas, Southern Mexico. Frugivorous bat species diversity (Shannon H') was similar between forest types. However, bat abundance was highest in rain forest and O. pyramidale forests. Bat species composition was different among forest types with more Carollia sowelli and Sturnira lilium captures in O. pyramidale forests. Overall, bat fruit consumption was dominated by early-successional shrubs, highest late-successional fruit consumption was found in rain forests and more bats consumed early-successional shrub fruits in O. pyramidale forests. Ochroma pyramidale forests presented a higher canopy openness, tree height, lower tree density and diversity of fruit than secondary forests. Tree density and canopy openness were negatively correlated with bat species diversity and bat abundance, but bat abundance increased with fruit abundance and tree height. Hence, secondary forest management alters forests' structural characteristics and resource availability, and shapes the frugivorous bat community structure, and thereby the fruit consumption by bats.

  18. The Specifications for Monitoring of Acid Rain

    Institute of Scientific and Technical Information of China (English)

    Tang Jie

    2011-01-01

    Background Since China is a country seriously affected by acid rain pollution,it is a long-term fundamental work for acid rain pollution prevention and control in China by getting well informed of the characteristics of spatial and temporal changes in acid rain and long-term trends of these changes.In order to reach the national demand for acid rain monitoring data,the China Meteorological Administration (CMA) began to construct the network of acid rain monitoring stations in 1992.By the end of 2010,the total number of monitoring stations has exceeded 340.

  19. The rain-powered cart

    Science.gov (United States)

    Mungan, Carl E.; Lipscombe, Trevor C.

    2016-09-01

    A frictionless cart in the shape of a right triangle (with the vertical side forward) is elastically impacted by vertically falling raindrops. The speed of the cart as a function of time can be analytically deduced as an exercise in the use of trigonometric and hyperbolic functions. A characteristic time defines the approach to a terminal speed which is a sizeable fraction of the speed of the rain. The treatment is accessible to a student in a calculus-based mechanics course.

  20. Acid Rain: What It Is -- How You Can Help!

    Science.gov (United States)

    National Wildlife Federation, Washington, DC.

    This publication discusses the nature and consequences of acid precipitation (commonly called acid rain). Topic areas include: (1) the chemical nature of acid rain; (2) sources of acid rain; (3) geographic areas where acid rain is a problem; (4) effects of acid rain on lakes; (5) effect of acid rain on vegetation; (6) possible effects of acid rain…

  1. Aboveground vs. Belowground Carbon Stocks in African Tropical Lowland Rainforest: Drivers and Implications.

    Directory of Open Access Journals (Sweden)

    Sebastian Doetterl

    Full Text Available African tropical rainforests are one of the most important hotspots to look for changes in the upcoming decades when it comes to C storage and release. The focus of studying C dynamics in these systems lies traditionally on living aboveground biomass. Belowground soil organic carbon stocks have received little attention and estimates of the size, controls and distribution of soil organic carbon stocks are highly uncertain. In our study on lowland rainforest in the central Congo basin, we combine both an assessment of the aboveground C stock with an assessment of the belowground C stock and analyze the latter in terms of functional pools and controlling factors.Our study shows that despite similar vegetation, soil and climatic conditions, soil organic carbon stocks in an area with greater tree height (= larger aboveground carbon stock were only half compared to an area with lower tree height (= smaller aboveground carbon stock. This suggests that substantial variability in the aboveground vs. belowground C allocation strategy and/or C turnover in two similar tropical forest systems can lead to significant differences in total soil organic C content and C fractions with important consequences for the assessment of the total C stock of the system.We suggest nutrient limitation, especially potassium, as the driver for aboveground versus belowground C allocation. However, other drivers such as C turnover, tree functional traits or demographic considerations cannot be excluded. We argue that large and unaccounted variability in C stocks is to be expected in African tropical rain-forests. Currently, these differences in aboveground and belowground C stocks are not adequately verified and implemented mechanistically into Earth System Models. This will, hence, introduce additional uncertainty to models and predictions of the response of C storage of the Congo basin forest to climate change and its contribution to the terrestrial C budget.

  2. Dispersal of seeds of Hymenaea courbaril (Fabaceae in a logged rain forest in the Peruvian Amazonian Dispersão de sementes de Hymenaea courbaril (Fabaceae em uma floresta tropical úmida com exploração madeireira na Amazônia peruana

    Directory of Open Access Journals (Sweden)

    David L. Gorchov

    2004-01-01

    Full Text Available Seed dispersal of Hymenaea courbaril was studied by following the fate of 585 seeds embedded with small magnets and set in displays in and near a logged strip in rain forest in the Peruvian Amazonian. Mammals took fruits from all displays, which were located in the forest, edge, and cleared strip. Overall removal rates were low - a median of 8.1 fruits / month from displays maintained with 8-10 fruits - but were higher in August than in earlier months. Most fruits were dropped near the display or had their seeds eaten, but > 13% were successfully dispersed. Most of the dispersed seeds were buried, which increases probability of germination. Maximum dispersal distance of live seeds was 12.1 m (median 3.1 m, but other magnets were transported up to 34 m, indicating seeds were dispersed further, but then eaten. Acouchies (most likely Myoprocta pratti and agoutis (Dasyprocta fuliginosa were apparently the main dispersal agents. Dispersal of seeds from the forest into the logged strip was rare, suggesting that although rodents disperse H. courbaril, they cannot be relied on for the reseeding this and similar species in recent clearings.Foi estudada a dispersão de sementes de Hymenaea courbaril, seguindo o destino de 585 sementes marcadas com imãs e expostas a potenciais dispersores, colocadas em agregados no interior e próximo de uma faixa de floresta cortada, na Amazónia peruana. Mamíferos retiraram frutos de todos os agregados, localizados no interior da floresta, na sua borda, e na clareira. As taxas de remoção foram baixas - mediana de 8.1 frutos/mês em agregados mantidos com 8-10 frutos - mas foram mais altas em agosto que nos primeiros meses do ano. A maior parte dos frutos foi abandonada próxima do agregado de origem ou as suas sementes foram consumidas, mas > 13% foram dispersos com sucesso. A maior parte das sementes dispersas foi enterrada, o que favorece a germinação. A distância máxima de dispersão de sementes vivas foi de

  3. Light-related variation in sapling architecture of three shade-tolerant tree species of the Mexican rain forest Variación arquitectural de árboles juveniles en relación con la luz en tres especies tolerantes a la sombra en una selva húmeda mexicana

    Directory of Open Access Journals (Sweden)

    JOSÉ LUIS MARTÍNEZ-SÁNCHEZ

    2008-09-01

    Full Text Available The crown architecture of three shade-tolerant tree species (two subcanopy and one mid-canopy was analyzed in relation to the light regime of the forest understorey. The aim was to examine to which extent shade-tolerant species variate in their crown architecture. Tree saplings (265 between 50 and 300 cm height, and distributed from understorey to variously-sized canopy gaps, were measured for 13 architectural traits in the lowland rain forest of Los Tuxtlas, México. The analysis showed that the three species changed their architecture as light increased but in a different way. No species conformed to the typical wide-crown type expected for shade-tolerant species, and in contrast they presented some traits of light demanding species. The two sub-canopy species tended to adopt a crown form between a narrow- and wide-crown type, and the mid-canopy species showed more traits of a narrow-crown type. The horizontal crown area appeared as the more related trait to the light and sapling height. It is concluded that despite being shade-tolerant, the studied species make use of better-lit environments in the forest understorey. The crown architecture of shade-tolerant species is not as rigid as originally conceived.Se analizó la arquitectura de la copa de tres especies tolerantes a la sombra (dos del sotobosque y una del dosel medio en relación con el ambiente lumínico del sotobosque de la selva. El objetivo fue examinar el grado de variación que presenta la arquitectura de la copa de especies tolerantes a la sombra. Para esto, se midieron 13 variables arquitecturales en 265 árboles juveniles (50-300 cm de altura distribuidos desde sitios de selva madura hasta claros de diversos tamaños, en la selva húmeda tropical de Los Tuxtlas, México. El análisis mostró que las tres especies cambian la arquitectura de su copa a medida que aumenta la disponibilidad de luz, pero de diferente forma. Ninguna especie presentó el típico modelo de copa plana

  4. Acid Rain Effects on Adirondack Streams - Results from the 2003-05 Western Adirondack Stream Survey (the WASS Project)

    Science.gov (United States)

    Lawrence, Gregory B.; Roy, Karen M.; Baldigo, Barry P.; Simonin, Howard A.; Passy, Sophia I.; Bode, Robert W.; Capone, Susan B.

    2009-01-01

    Traditionally lakes have been the focus of acid rain assessments in the Adirondack region of New York. However, there is a growing recognition of the importance of streams as environmental indicators. Streams, like lakes, also provide important aquatic habitat, but streams more closely reflect acid rain effects on soils and forests and are more prone to acidification than lakes. Therefore, a large-scale assessment of streams was undertaken in the drainage basins of the Oswegatchie and Black Rivers; an area of 4,585 km2 in the western Adirondack region where acid rain levels tend to be highest in New York State.

  5. The comparative phylogeography of fruit bats of the tribe Scotonycterini (Chiroptera, Pteropodidae) reveals cryptic species diversity related to African Pleistocene forest refugia.

    Science.gov (United States)

    Hassanin, Alexandre; Khouider, Souraya; Gembu, Guy-Crispin; Goodman, Steven M; Kadjo, Blaise; Nesi, Nicolas; Pourrut, Xavier; Nakouné, Emmanuel; Bonillo, Céline

    2015-03-01

    The hypothesis of Pleistocene forest refugia was tested using comparative phylogeography of Scotonycterini, a fruit bat tribe endemic to Africa containing four species: Scotonycteris zenkeri, Casinycteris argynnis, C. campomaanensis, and C. ophiodon. Patterns of genetic structure were assessed using 105 Scotonycterini (including material from three holotypes) collected at 37 localities, and DNA sequences from the mitochondrial cytochrome b gene (1140 nt) and 12 nuclear introns (9641 nt). Phylogenetic trees and molecular dating were inferred by Bayesian methods. Multilocus analyses were performed using supermatrix, SuperTRI, and *BEAST approaches. Mitochondrial analyses reveal strong phylogeographical structure in Scotonycteris, with four divergent haplogroups (4.9-8.7%), from Upper Guinea, Cameroon, western Equatorial Africa, and eastern Democratic Republic of the Congo (DRC). In C. argynnis, we identify two mtDNA haplogroups corresponding to western and eastern Equatorial Africa (1.4-2.1%). In C. ophiodon, the mtDNA haplotypes from Cameroon and Ivory Coast differ by only 1.3%. Nuclear analyses confirm the validity of the recently described C. campomaanensis and indicate that western and eastern populations of C. argynnis are not fully isolated. All mtDNA clusters detected in Scotonycteris are found to be monophyletic based on the nuclear dataset, except in eastern DRC. In the nuclear tree, the clade from western Equatorial Africa is closely related to individuals from eastern DRC, whereas in the mitochondrial tree it appears to be the sister-group of the Cameroon clade. Migrate-n analyses support gene flow from western Equatorial Africa to eastern DRC. Molecular dating indicates that Pleistocene forest refugia have played an important role in shaping the evolution of Scotonycterini, with two phases of allopatric speciation at approximately 2.7 and 1.6 Mya, resulting from isolation in three main forest areas corresponding to Upper Guinea, Cameroon, and Equatorial

  6. Detecting floristic structure and pattern across topographic and moisture gradients in a mixed species Central African forest using IKONOS and Landsat-7 ETM+ images

    Science.gov (United States)

    Thenkabail, Prasad S.; Hall, Jefferson; Lin, Tiffany; Ashton, Mark S.; Harris, David; Enclona, Eden A.

    2003-06-01

    The strengths and limitations of high spatial resolution broadband IKONOS data and Landsat-7 ETM+ data are compared with respect to, distinguishing floristic structure (basal area, stem density) and pattern (diversity indices, species associations) across a topography that exhibits subtle variations in surface hydrology and elevation. Three site types can be described in relation to the topography and hydrology of the study area: (1) seasonally drought stressed; (2) valley streams; and (3) well-drained bottomlands. Non-metric Multidimensional Scaling (NMS) emphasized the importance of seasonal moisture stress in determining floristic structure and species associations in this forest. Forest structure and species data gathered across the three sites of the topographic/hydrologic gradient are related to spectral values and indices gathered from IKONOS and ETM+. Statistical tests of significance at 95% confidence level or higher showed that the IKONOS wavebands and vegetation indices were most sensitive to changes in floristic structure and species composition for images taken during the dry season (October-March) as compared to those for the wet season (April-September). Within the IKONOS data, the near-infrared (NIR) waveband (band 4) was most sensitive to changes in forest structure and species composition across the three site types (seasonally drought stressed; valley streams; and well-drained bottomlands). However, the IKONOS spectral relationships with biotic variables did not exceed an R2 value of 0.34, with an overwhelming number of best regression models having any two waveband combinations; typically combinations of band 1 and 2, or 1 and 3, or 2 and 3. The best relationships were obtained when ETM+ mid-infrared (MIR) band 5 or 7 were involved with R2 values of 0.52 and 0.54 for basal area and stem density respectively, explaining about 20% greater variability compared to IKONOS data. Thereby, the most interesting aspect of the paper was the degree to which

  7. Contrasting patterns of gene flow between sister plant species in the understorey of African moist forests - the case of sympatric and parapatric Marantaceae species.

    Science.gov (United States)

    Ley, A C; Hardy, O J

    2014-08-01

    Gene flow within and between species is a fundamental process shaping the evolutionary history of taxa. However, the extent of hybridization and reinforcement is little documented in the tropics. Here we explore the pattern of gene flow between three sister species from the herbaceous genus Marantochloa (Marantaceae), sympatrically distributed in the understorey of the African rainforest, using data from the chloroplast and nuclear genomes (DNA sequences and AFLP). We found highly contrasting patterns: while there was no evidence of gene flow between M. congensis and M. monophylla, species identity between M. monophylla and M. incertifolia was maintained despite considerable gene flow. We hypothesize that M. incertifolia originated from an ancient hybridization event between M. congensis and M. monophylla, considering the current absence of hybridization between the two assumed parent species, the rare presence of shared haplotypes between all three species and the high percentage of haplotypes shared by M. incertifolia with each of the two parent species. This example is contrasted with two parapatrically distributed species from the same family in the genus Haumania forming a hybrid zone restricted to the area of overlap. This work illustrates the diversity of speciation/introgression patterns that can potentially occur in the flora of tropical Africa.

  8. Rain on small tropical islands

    Science.gov (United States)

    Sobel, A. H.; Burleyson, C. D.; Yuter, S. E.

    2011-04-01

    A high-resolution rainfall climatology based on observations from the Tropical Rainfall Measuring Mission's Precipitation Radar (PR) instrument is used to evaluate the influence of small tropical islands on climatological rainfall. Islands with areas between one hundred and several thousand km2 are considered in both the Indo-Pacific Maritime Continent and Caribbean regions. Annual mean climatological (1997-2007) rainfall over each island is compared with that over the surrounding ocean region, and the difference is expressed as a percentage. In addition to total rainfall, rain frequency and intensity are also analyzed. Results are stratified into two 12 h halves of the diurnal cycle as well as eight 3 h periods, and also by a measure of each island's topographic relief. In both regions, there is a clear difference between larger islands (areas of a few hundred km2 or greater) and smaller ones. Both rain frequency and total rainfall are significantly enhanced over larger islands compared to the surrounding ocean. For smaller islands the enhancement is either negligibly small, statistically insignificant, or, in the case of Caribbean rain frequency, negative. The enhancement in total rainfall over larger islands is partly attributable to greater frequency and partly to greater intensity. A diurnal cycle in island enhancement is evident in frequency but not intensity, except over small Caribbean islands where the converse is true. For the larger islands, higher orography is associated with greater rainfall enhancements. The orographic effect is larger (percentagewise) in the Caribbean than in the Maritime Continent. Orographic precipitation enhancement manifests more strongly as increased frequency of precipitation rather than increased intensity and is present at night as well as during the day. The lack of a clear diurnal cycle in orographic enhancement suggests that much of the orographic rainfall enhancement is attributable to mechanically forced upslope flow

  9. 凉风坳亚热带次生常绿阔叶林土壤种子库和种子雨的特征研究%Primary research on the soil seed bank and seed rain of semi-tropical evergreen-broadleaf forests in LiangFengao of Sichuan

    Institute of Scientific and Technical Information of China (English)

    张丹桔; 宫渊波; 张健

    2012-01-01

    The soil seed banks, seed rain and natural germination are the main constructive parts of the forestry eco-system, which make an indispensable contribution to the vegetation regeneration, succession and diffusion. However, there are little information available for this. In the present study, semi-tropical evergreen-broad leaf forests in Muchuan of Sichuan basin in China were studied on the soil seed bank, seed rain and the germination of the seeds in the soil seed bank under natural conditions before and after the seed' s falling. Furthermore, the factors influencing the soil seed bank were evaluated. The density of the seed banks including 22 leading species arranges 643. 2 ~ 889. 2 ind · m -2 along with time. The soil seed banks in all sample sites were dominated by perennial herbaceous species in terms of species richness and density. Shannon-Wiener index decreased with time, Simpson index showed the reverse trend compared with the Shannon-Wiener index. Pielou index decreased in December, 2004 and then increased in May, 2005. The density of soil seed banks decreased with the depth of the soil layer. It was found that seeds at the litter layers were shorter than that in the superficial soil layer (0-10 cm) , however,most seeds of the arbor trees existed at the litter layers. The species richness and density of soil seed bank in the control plantations were significantly lower than that in studied forests. The seed input each year in the studies forests were 142. 3 ind · m-2 , the output of the valid seeds each year were 268. 9 ind · m-2 . Preying were the main factors resulting in the seed loss. The species similarity between the seed bank and the above ground vegetation were low but that in control plantations were high.%选择四川省沐川县凉风坳亚热带次生常绿阔叶林为研究对象,在2004年5月、2004年12月和2005年5月对其林下土壤种子库、种子雨以及种子天然萌发状况等方面进行系统调查及

  10. Climate change as a confounding factor in reversibility of acidification: RAIN and CLIMEX projects

    OpenAIRE

    Wright, R. F.; Jenkins, A

    2001-01-01

    International audience; The RAIN and CLIMEX experiments at Risdalsheia, southernmost Norway, together cover 17 years (1984-2000) of whole-catchment manipulation of acid deposition and climate. A 1200 m2 roof placed over the forest canopy at KIM catchment excluded about 80% of ambient acid deposition; clean rain was sprinkled under the roof. A climate change treatment (3.7°C increase in air temperature and increase in air carbon dioxide concentrations to 560 ppmv) was superimposed on the clean...

  11. Acid rain information book. Draft final report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-12-01

    Acid rain is one of the most widely publicized environmental issues of the day. The potential consequences of increasingly widespread acid rain demand that this phenomenon be carefully evaluated. Reveiw of the literature shows a rapidly growing body of knowledge, but also reveals major gaps in understanding that need to be narrowed. This document discusses major aspects of the acid rain phenomenon, points out areas of uncertainty, and summarizes current and projected research by responsible government agencies and other concerned organizations.

  12. Coalescent models reveal the relative roles of ancestral polymorphism, vicariance, and dispersal in shaping phylogeographical structure of an African montane forest robin.

    Science.gov (United States)

    Bowie, Rauri C K; Fjeldså, Jon; Hackett, Shannon J; Bates, John M; Crowe, Timothy M

    2006-01-01

    Although many studies have documented the effect of glaciation on the evolutionary history of Northern Hemisphere flora and fauna, this study is the first to investigate how the indirect aridification of Africa caused by global cooling in response to glacial cycles at higher latitudes has influenced the evolutionary history of an African montane bird. Mitochondrial DNA sequences from the NADH 3 gene were collected from 283 individual Starred Robins (Pogonocichla stellata, Muscicapoidea). At least two major vicariant events, one that separated the Albertine Rift from all but the Kenyan Highlands around 1.3-1.2 Myrs BP, and another that separated the Kenyan Highlands from the northern Eastern Arc, and the northern Eastern Arc from the south-central Eastern Arc between 0.9 and 0.8 Myrs BP appear to underlie much of the observed genetic diversity and structure within Starred Robin populations. These dates of divergence suggest a lack of recurrent gene flow; although the Albertine Rift and south-central Eastern Arc share haplotypes, based on coalescent analyses this can confidently be accounted for by ancestral polymorphism as opposed to recurrent gene flow. Taken collectively, strong evidence exists for recognition of four major ancestral populations: (1) Kenyan Highlands (subspecies keniensis), (2) Albertine Rift (ruwenzori), (3) northern Eastern Arc (helleri), and (4) south-central Eastern Arc, Ufipa and the Malawi Rift (orientalis). The estimated divergence times cluster remarkably around one of the three estimated peaks of aridification in Africa during the Plio-Pleistocene centred on 1 Myrs BP. Further, time to most recent common ancestor (TMRCA) estimates (1.7-1.6 Myrs BP) of gene divergence between the Albertine Rift and the other montane highlands corresponds closely with a second estimated peak of aridification at about 1.7 Myrs BP. Collectively, these results suggest that aridification of Africa in response to glaciation at higher latitudes during the

  13. Espaçamento para o cultivo da bananeira 'Comprida verdadeira' (Musa AAB na zona da mata sul de Pernambuco (1° Ciclo Spacing on 'Comprida verdadeira' plantain (Musa AAB cultivatated in the south rain forest region of Pernambuco state, Brazil (1st. cycle

    Directory of Open Access Journals (Sweden)

    Roberto José Mello de Moura

    2002-12-01

    Full Text Available O presente trabalho objetivou definir o melhor espaçamento no desenvolvimento e rendimento da bananeira-'Comprida Verdadeira' na Zona da Mata Sul de Pernambuco. O experimento foi conduzido em delineamento de blocos ao acaso, com três tratamentos, constituídos por três diferentes espaçamentos (3,0 x 2,0 m, 2,5 x 2,0 m e 2,0 x 2,0 m e três repetições. Foram avaliados a altura da planta, circunferência do pseudocaule, número de filhos e folhas emitidos, número de dias do plantio à emissão da inflorescência e colheita, peso do cacho e das pencas, número de frutos e de pencas/cacho, comprimento e diâmetro do fruto, e espessura da casca. As diferentes distâncias entre plantas não influenciaram na produtividade do primeiro ciclo. Entretanto, os espaçamentos 3,0 x 2,0 m e 2,5 x 2,0 m promoveram a produção de cachos maiores, bem como frutos com melhores características físicas.This work aimed to define adequate spacings for the development and yield of 'Comprida Verdadeira' plantain in the South Rain Forest Region of Pernambuco State, Brazil. Experimental design of randomized bloks with three treatments, composed of three distinct spacings (3.0 x 2.0 m, 2.5 x 2.0 m and 2.0 x 2.0 m, and three replicates were utilized. The characteristics evaluated were: plant height, pseudostem circunference, numbers of suckers and leaves emitted, days from planting to inflorescence emission and harvest, bunch and hands weights, numbers of fruits and hands per bunch, fruit lenght and diameter, and skin thickness. Different distances had no effect on first cycle productivity. However, 3.0 x 2.0 m and 2.5 x 2.0 m spacings increased yield of bunch weight, and fruits showed the best physical characteristics.

  14. Acid Thunder: Acid Rain and Ancient Mesoamerica

    Science.gov (United States)

    Kahl, Jonathan D. W.; Berg, Craig A.

    2006-01-01

    Much of Mesoamerica's rich cultural heritage is slowly eroding because of acid rain. Just as water dissolves an Alka-Seltzer tablet, acid rain erodes the limestone surfaces of Mexican archaeological sites at a rate of about one-half millimeter per century (Bravo et al. 2003). A half-millimeter may not seem like much, but at this pace, a few…

  15. Acid Rain. LC Science Tracer Bullet.

    Science.gov (United States)

    Hollmann, Pauline, Comp.

    The term "acid rain," also called "acid precipitation," generally refers to any precipitation having a pH value of less than 5.6. This guide to the literature on acid rain in the collections of the Library of Congress is not necessarily intended to be a comprehensive bibliography. It is designed to provide the reader with a set…

  16. Indigenous Systems within the African-American Community

    Science.gov (United States)

    Marbley, Aretha Faye; Rouson, Leon

    2011-01-01

    For the African-American family, life ain't been no crystal stair. The African-American family has trotted for over 400 years through a wilderness of racism, poverty, discrimination of all kinds, crossing seas of monsters and forests of demons. Yet, despite the numerous obstacles and attacks that society has mounted against it since slavery, the…

  17. Scale Dependence of Spatiotemporal Intermittence of Rain

    Science.gov (United States)

    Kundu, Prasun K.; Siddani, Ravi K.

    2011-01-01

    It is a common experience that rainfall is intermittent in space and time. This is reflected by the fact that the statistics of area- and/or time-averaged rain rate is described by a mixed distribution with a nonzero probability of having a sharp value zero. In this paper we have explored the dependence of the probability of zero rain on the averaging space and time scales in large multiyear data sets based on radar and rain gauge observations. A stretched exponential fannula fits the observed scale dependence of the zero-rain probability. The proposed formula makes it apparent that the space-time support of the rain field is not quite a set of measure zero as is sometimes supposed. We also give an ex.planation of the observed behavior in tenus of a simple probabilistic model based on the premise that rainfall process has an intrinsic memory.

  18. A importância de Reservas Particulares do Patrimônio Natural para a conservação da brioflora da Mata Atlântica: um estudo em El Nagual, Magé, RJ, Brasil The importance of Private Natural Heritage Reserves for conservation of Atlantic rain forest bryoflora: a study at El Nagual, Magé, Rio de Janeiro State, Brazil

    Directory of Open Access Journals (Sweden)

    Nivea Dias dos Santos

    2008-06-01

    Full Text Available Foi realizado o levantamento das briófitas da RPPN El Nagual, uma área de floresta submontana no Estado do Rio de Janeiro. Foram registradas 137 espécies (um antócero, 70 hepáticas e 66 musgos e duas variedades, distribuídas em 75 gêneros e 37 famílias, sendo cinco novas ocorrências para o estado. Lejeuneaceae (27 spp., Pilotrichaceae (17 spp., Aneuraceae (9 spp. e Calymperaceae (8 spp. destacam-se pela riqueza de espécies (44% da brioflora. Sete formas de vida foram caracterizadas, predominando trama (37%, tufo (16% e talosa (15%. Seis tipos de substrato são colonizados na área, predominando espécies corticícolas (52% e rupícolas (42%. Em relação aos padrões de distribuição, predominaram espécies neotropicais e pantropicais. Foram encontradas quatro espécies caracterizadas como vulneráveis no estado. Os resultados demonstram que a brioflora da RPPN é rica e evidenciam a importância dessa categoria de unidade de conservação na proteção de remanescentes de Mata Atlântica e conservação da brioflora.A floristic survey of the bryophytes was carried out in the El Nagual Private Natural Heritage Reserve, a submontane Atlantic rain forest remnant in Rio de Janeiro state. One hundred and thirty seven species were recorded (one Anthocerotae, 70 hepatics and 66 mosses plus two varieties, in 75 genera and 37 families. Five species are new records for Rio de Janeiro state. Lejeuneaceae (27 spp., Pilotrichaceae (17 spp., Aneuraceae (9 spp., and Calymperaceae (8 spp. are especially rich in species (44% of the bryoflora. Seven life-forms were found; the most common are weft (37%, turf (16%, and thallose (15%. Six kinds of substrate were colonized, the most important species types being corticicolous (52% and rupicolous (42%. The most common distribution patterns were Neotropical and Pantropical. Four species were considered to be vulnerable in the state. The results show that the bryoflora of the El Nagual Reserve is relatively

  19. Comparisons of water quality parameters from diverse catchments during dry periods and following rain events.

    Science.gov (United States)

    Shah, Vikaskumar G; Dunstan, R Hugh; Geary, Phillip M; Coombes, Peter; Roberts, Timothy K; Rothkirch, Tony

    2007-08-01

    In this study, 12 catchments sites located along the north coast of New South Wales in Australia were grouped into the four categories of septic, cattle, sewage treatment plant (STP) and forested sites via cluster analysis based on their land use patterns. Water samples from all these sites were collected between October 2004 and June 2006 at a regular monthly interval and within 48 h of rain events. The samples were analyzed for bacterial counts including faecal coliform and total coliform; faecal sterols including coprostanol, epicoprostanol, cholesterol, cholestanol, 24-ethylcoprostanol, campesterol, stigmasterol and beta-sitosterol; and the elements including Na, Rb, Sr, Ag, Cd, Sn, Cs, Ba, Hg, Tl, Pb, Bi, U, Mg, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, K, As, Se, P and Mo. Over the course of the sampling period, the STP site had the highest average coprostanol level of 1693+/-567 ng/L which was significantly higher (prain events analyses of the data set revealed that elevated levels of both coprostanol and faecal coliforms were not exclusive to rain events. The average coprostanol levels in rain event samples at each site were not significantly different compared with the corresponding dry event samples. Conversely, faecal coliform numbers increased by 2-4 times in rain events samples from septic, cattle and forested sites, but did not alter in the STP site. Multivariate analyses identified coprostanol and Sr as major contributing factors for the discrimination of septic, cattle, STP and forested sites for both rain and dry events samples. It was clear that each land use type of catchment could be characterized by biochemical, bacteriological and elemental parameters.

  20. Comparative proteomic analysis of differentially expressed proteins in β-aminobutyric acid enhanced Arabidopsis thaliana tolerance to simulated acid rain.

    Science.gov (United States)

    Liu, Tingwu; Jiang, Xinwu; Shi, Wuliang; Chen, Juan; Pei, Zhenming; Zheng, Hailei

    2011-05-01

    Acid rain is a worldwide environmental issue that has seriously destroyed forest ecosystems. As a highly effective and broad-spectrum plant resistance-inducing agent, β-aminobutyric acid could elevate the tolerance of Arabidopsis when subjected to simulated acid rain. Using comparative proteomic strategies, we analyzed 203 significantly varied proteins of which 175 proteins were identified responding to β-aminobutyric acid in the absence and presence of simulated acid rain. They could be divided into ten groups according to their biological functions. Among them, the majority was cell rescue, development and defense-related proteins, followed by transcription, protein synthesis, folding, modification and destination-associated proteins. Our conclusion is β-aminobutyric acid can lead to a large-scale primary metabolism change and simultaneously activate antioxidant system and salicylic acid, jasmonic acid, abscisic acid signaling pathways. In addition, β-aminobutyric acid can reinforce physical barriers to defend simulated acid rain stress.

  1. Forest dynamics.

    Science.gov (United States)

    Frelich, Lee

    2016-01-01

    Forest dynamics encompass changes in stand structure, species composition, and species interactions with disturbance and environment over a range of spatial and temporal scales. For convenience, spatial scale is defined as individual tree, neighborhood, stand, and landscape. Whether a given canopy-leveling disturbance will initiate a sequence of development in structure with little change in composition or initiate an episode of succession depends on a match or mismatch, respectively, with traits of the dominant tree species that allow the species to survive disturbance. When these match, certain species-disturbance type combinations lock in a pattern of stand and landscape dynamics that can persist for several generations of trees; thus, dominant tree species regulate, as well as respond to, disturbance. A complex interaction among tree species, neighborhood effects, disturbance type and severity, landform, and soils determines how stands of differing composition form and the mosaic of stands that compose the landscape. Neighborhood effects (e.g., serotinous seed rain, sprouting, shading, leaf-litter chemistry, and leaf-litter physical properties) operate at small spatial extents of the individual tree and its neighbors but play a central role in forest dynamics by contributing to patch formation at stand scales and dynamics of the entire landscape. Dominance by tree species with neutral to negative neighborhood effects leads to unstable landscape dynamics in disturbance-prone regions, wherein most stands are undergoing succession; stability can only occur under very low-severity disturbance regimes. Dominance by species with positive effects leads to stable landscape dynamics wherein only a small proportion of stands undergo succession at any one time. Positive neighborhood effects are common in temperate and boreal zones, whereas negative effects are more common in tropical climates. Landscapes with positive dynamics have alternate categories of dynamics

  2. Chemical characterization of fog and rain water collected at the eastern Andes cordillera

    Directory of Open Access Journals (Sweden)

    E. Beiderwieden

    2005-01-01

    Full Text Available During a three month period in 2003 and 2004, the chemistry of fog and rainwater were studied at the 'El Tiro' site in a tropical mountain forest ecosystem in Ecuador, South America. The fogwater samples were collected using a passive fog collector, and for the rain water, a standard rain sampler was employed. For all samples, electric conductivity, pH, and the concentrations of NH4+, K+, Na+, Ca2+, Mg2+, Cl−, NO3−, PO43−, and SO42− were measured. For each fog sample, a 5 day back trajectory was calculated by the use of the HYSPLIT model. Two types of trajectories occurred. One type was characterized by advection of air masses from the East over the Amazonian basin, the other trajectory arrived one from the West after significant travel time over the Pacific Ocean. We found considerably higher ion concentrations in fogwater samples than in rain samples. Median pH values are 4.58 for fog water, and 5.26 for the rain samples, respectively. The median electric conductivity was 23 μS cm−1 for the fog and 6 μS cm−1 for the rain. The continent samples exhibit higher concentrations of most ions as compared to the pacific samples, but these differences could not be detected statistically.

  3. Atmospheric Deposition of Sulfur and Base Cations to European Forests

    OpenAIRE

    Ivens, W.

    1988-01-01

    To simulate acidification processes in forests (soils), it is important to know as well as possible the atmospheric input. Large scale models have recently been improved to take better into account the differences in deposition between forests and other surfaces. In this report measurements of sulfur-fluxes onto the forest floor (54 case studies) are compared with deposition fluxes as calculated by the EMEP-model and by the RAINS modifications on this model. The value of the filtering pa...

  4. Endemic and exotic tropical forests of Réunion Island observed by airborne lidar

    Science.gov (United States)

    Shang, Xiaoxia; Chazette, Patrick; Totems, Julien; Dieudonné, Elsa; Hamonou, Eric; Duflot, Valentin; Strasberg, Dominique; Flores, Olivier; Fournel, Jacques; Tulet, Pierre

    2015-04-01

    Tropical forests are vital ecosystems widely threatened across the globe and yet remain the most difficult forest type to document. They are strongly perturbed by anthropogenic activities, which lead to coexistence of endemic and exotic tree species. We present an experiment performed over Réunion Island in May 2014, on sites ranging from coastal to rain forest, including tropical montane cloud forest as found on the Bélouve plateau. Réunion Island is home to the last remnants of primary tropical forest in the Mascarene archipelago, and still shelters significant biodiversity. Three key ecological parameters have been extracted from the lidar measurements: the canopy height (CH), the forest leaf area index (LAI) and the apparent foliage profile. The mean values of estimated LAI are between ~5 and 8 m2/m2 and the mean CH values are ~15 m for both tropical montane cloud and rain forests. Good agreement is found between Lidar- and MODIS-derived LAI for moderate LAI, but the LAI retrieved from lidar is larger than MODIS on rain forest sites (~8 against ~6 m2/m2 from MODIS). Regarding the characterization of tropical biomes, we show that the rain and montane tropical forests can be well distinguished from the planted forests by the use of the three ecological parameters retrieved, as the endemic and exotic forests can also be well distinguished.

  5. African America.

    Science.gov (United States)

    Brodie, Carolyn S.; Brown, Gloria

    1994-01-01

    Presents an annotated bibliography of quality materials by and about African Americans in the areas of poetry, music, folklore, women, picture books, history/collective biography, authors, and professional materials. Activities are suggested in each area for Black History Month. (LRW)

  6. Pre-rain green-up is ubiquitous across southern tropical Africa: implications for temporal niche separation and model representation.

    Science.gov (United States)

    Ryan, Casey M; Williams, Mathew; Grace, John; Woollen, Emily; Lehmann, Caroline E R

    2017-01-01

    Tree phenology mediates land-atmosphere mass and energy exchange and is a determinant of ecosystem structure and function. In the dry tropics, including African savannas, many trees grow new leaves during the dry season - weeks or months before the rains typically start. This syndrome of pre-rain green-up has long been recognized at small scales, but the high spatial and interspecific variability in leaf phenology has precluded regional generalizations. We used remote sensing data to show that this precocious phenology is ubiquitous across the woodlands and savannas of southern tropical Africa. In 70% of the study area, green-up preceded rain onset by > 20 d (42% > 40 d). All the main vegetation formations exhibited pre-rain green-up, by as much as 53 ± 18 d (in the wet miombo). Green-up showed low interannual variability (SD between years = 11 d), and high spatial variability (> 100 d). These results are consistent with a high degree of local phenological adaptation, and an insolation trigger of green-up. Tree-tree competition and niche separation may explain the ubiquity of this precocious phenology. The ubiquity of pre-rain green-up described here challenges existing model representations and suggests resistance (but not necessarily resilience) to the delay in rain onset predicted under climate change.

  7. Chemistry of rain events in West Africa: evidence of dust and biogenic influence in convective systems

    Directory of Open Access Journals (Sweden)

    K. Desboeufs

    2010-10-01

    Full Text Available This paper documents the chemical composition of 7 rain events associated with mesoscale convective systems sampled at the supersite of Banizoumbou, Niger, during the first special observation periods (June–July 2006 of the African Monsoon Multidisciplinary Analyses (AMMA experiment. Time-resolved rain sampling was performed in order to discriminate the local dust scavenged at the beginning of rain event from the aerosol particles incorporated in the cloud at the end of the rain. The total elemental composition is dominated by Al, Si, Fe and Ca, indicating a high influence of dust and limited marine or anthropogenic contribution. After the aerosol wash-out, the elemental concentrations normalized to Al and the microscopic observations of diatoms, a tracer of the Bodélé depression, both indicate that the total elemental composition of rainwater is controlled by dust originating from North-eastern Saharan sources and probably incorporated in the convective cloud from the Harmattan layer. The low variability of the rain composition over the measurement period indicates a regional and temporal homogeneity of dust composition in the Harmattan layer. In the dissolved phase, the dominant anions are nitrate (NO3, sulphate (SO42− and chloride (Cl. However, between June and July we observe an increasing contribution of the organic anions (formate, acetate, oxalate associated with biogenic emissions to the total ion composition. These results confirm the large influence of biogenic emissions on the rain composition over Sahel during the wet season. The paper concludes on the capacity of mesoscale convective systems to carry simultaneously dust and biogenic compounds originating from different locations and depose them jointly. It also discusses the potential biogeochemical impact of such a phenomenon.

  8. NESDIS Blended Rain Rate (RR) Products

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The blended Rain Rate (RR) product is derived from multiple sensors/satellites. The blended products were merged from polar-orbiting and geostationary satellite...

  9. Rain Erosion/Measurement Impact Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The FARM Rain Erosion/Impact Measurement Lab develops solutions for deficiencies in the ability of materials, coatings and designs to withstand a severe operational...

  10. TECHNOLOGICAL OPTIONS FOR ACID RAIN CONTROL

    Science.gov (United States)

    Discussed are acid rain control options available to the electric utility industry. They include coal switching, flue gas desulfurization, and such emerging lower cost technologies as Limestone Injection Multistage Burners (LIMB) and Advanced Silicate (ADVACATE), both developed ...

  11. Raine syndrome: expanding the radiological spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Koob, Meriam; Dietemann, Jean-Louis [CHU de Strasbourg Hopital de Hautepierre, Service de Radiologie 2, Strasbourg (France); Doray, Berenice; Fradin, Melanie [CHU de Strasbourg, Hopital de Hautepierre, Laboratoire de Genetique Medicale, Strasbourg (France); Astruc, Dominique [CHU de Strasbourg Hopital de Hautepierre, Service de Neonatologie, Strasbourg (France)

    2011-03-15

    We describe ante- and postnatal imaging of a 1-year-old otherwise healthy girl with Raine syndrome. She presented with neonatal respiratory distress related to a pyriform aperture stenosis, which was diagnosed on CT. Signs of chondrodysplasia punctata, sagittal vertebral clefting and intervertebral disc and renal calcifications were also found on imaging. This new case confirms that Raine syndrome is not always lethal. The overlapping imaging signs with chondrodysplasia punctata and the disseminated calcifications give new insights into its pathophysiology. (orig.)

  12. Simulating Rain Fade In A Communication System

    Science.gov (United States)

    Shalkhauser, Kurt A.; Nagy, Lawrence A.; Svoboda, James K.

    1994-01-01

    Automated, computer-controlled assembly of electronic equipment developed for use in simulation testing of downlink portion of Earth/satellite microwave digital communication system. Designed to show effects upon performance of system of rain-induced fading in received signal and increases in transmitted power meant to compensate for rain-induced fading. Design of communication system improved iteratively in response to results of simulations, leading eventually to design ensuring clear, uninterrupted transmission of digital signals.

  13. Acid rain may cause senile dementia

    Energy Technology Data Exchange (ETDEWEB)

    Pearce, F.

    1985-04-25

    Aluminium, released from the soil by acid rain, may be a cause of several forms of senile dementia including Parkinson's disease and Alzheimer's disease. Many upland reservoirs, fed by acid rain, supply homes with water laced with significant amounts of aluminium. Studies in the Pacific have shown that communities living on soils that are extremely rich in bauxite, the rock containing aluminium, have a very high incidence of Alzheimer's disease.

  14. African-American Biography.

    Science.gov (United States)

    Martin, Ron

    1995-01-01

    Suggests sources of information for African American History Month for library media specialists who work with students in grades four through eight. Gale Research's "African-American Reference Library," which includes "African-America Biography,""African-American Chronology," and "African-American Almanac,"…

  15. African Trypanosomiasis

    Science.gov (United States)

    2011-06-01

    Histol. 1977;375:53- 70. 42. Poltera AA, Owor R, Cox JN. Pathological aspects of human African trypanosomiasis (HAT) in Uganda. A post - mortem survey of...nodular lesions , including anthrax or tick bite associated with Rickettsia conorii infection. The chancre is followed by a hemolymphatic stage, dur- ing...electrocardiograph- ic changes and, at times, terminal cardiac insufficiency.41 Pulmonary lesions specifically related to trypanosomiasis are not

  16. Forest rights

    DEFF Research Database (Denmark)

    Balooni, Kulbhushan; Lund, Jens Friis

    2014-01-01

    One of the proposed strategies for implementation of reducing emissions from deforestation and forest degradation plus (REDD+) is to incentivize conservation of forests managed by communities under decentralized forest management. Yet, we argue that this is a challenging road to REDD+ because......+ transactions costs. Third, beyond the “conservation islands” represented by forests under decentralized management, processes of deforestation and forest degradation continue. Given these challenges, we argue that REDD+ efforts through decentralized forestry should be redirected from incentivizing further...

  17. Obesity and African Americans

    Science.gov (United States)

    ... Data > Minority Population Profiles > Black/African American > Obesity Obesity and African Americans African American women have the ... ss6304.pdf [PDF | 3.38MB] HEALTH IMPACT OF OBESITY More than 80 percent of people with type ...

  18. MULTIDIMENSIONAL MODELING OF CORONAL RAIN DYNAMICS

    Energy Technology Data Exchange (ETDEWEB)

    Fang, X.; Xia, C.; Keppens, R. [Centre for mathematical Plasma Astrophysics, Department of Mathematics, KU Leuven, B-3001 Leuven (Belgium)

    2013-07-10

    We present the first multidimensional, magnetohydrodynamic simulations that capture the initial formation and long-term sustainment of the enigmatic coronal rain phenomenon. We demonstrate how thermal instability can induce a spectacular display of in situ forming blob-like condensations which then start their intimate ballet on top of initially linear force-free arcades. Our magnetic arcades host a chromospheric, transition region, and coronal plasma. Following coronal rain dynamics for over 80 minutes of physical time, we collect enough statistics to quantify blob widths, lengths, velocity distributions, and other characteristics which directly match modern observational knowledge. Our virtual coronal rain displays the deformation of blobs into V-shaped features, interactions of blobs due to mostly pressure-mediated levitations, and gives the first views of blobs that evaporate in situ or are siphoned over the apex of the background arcade. Our simulations pave the way for systematic surveys of coronal rain showers in true multidimensional settings to connect parameterized heating prescriptions with rain statistics, ultimately allowing us to quantify the coronal heating input.

  19. RAINS: Regional Air Pollution Information and Simulation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-12-01

    Only one computer model has ever been at the center of major international environmental negotiations. That model is RAINS. Twice it has been central to renegotiation of the Convention of Long-range Transboundary Air Pollution, the umbrella convention regarding air pollution across all Europe. It also underpins the European Union policy and directives on air pollution. Countries in Southeast Asia are turning to the model for help with their growing air pollution problems. RAINS will be used to determine emission ceilings for emissions of four key pollutants in EU countries - sulphur, ammonia, nitrogen oxides and volatile organic compounds. The same four pollutants are also the subject of a parallel negotiation in Geneva under the convention on Long-range Transboundary Air Pollution. The article and illustrations outline the model`s development and its structure in 1998, the historic role it has played in negotiations and some examples of its output. They highlight the central role of IIASA`s Transboundary Air Pollution project where a team of 12 works on the RAINS model and related issues. IIASA`s next goal is to develop a model of particulates pollution and incorporate it into RAINS. The information needed (such as particle sizes and chemical properties) and at what geographical scale must be identified to create an inventory of emissions suitable for RAINS modelling. 6 figs., 1 tab.

  20. Variação intraspecífica do lenho de Pseudopiptadenia contorta (DC. G.P. Lewis & M.P. Lima (Leguminosae - Mimosoideae de populações ocorrentes em dois remanescentes de Floresta Atlântica Intraspecific variation in wood anatomy of Pseudopiptadenia contorta (DC G.P. Lewis & M.P. Lima (Leguminosae -Mimosoidae in two Atlantic rain forest remnants

    Directory of Open Access Journals (Sweden)

    Maria Luiza R. da Costa Ribeiro

    2006-12-01

    Full Text Available O presente trabalho compara populações distintas de Pseudopiptadenia contorta (DC. G.P. Lewis & M.P. Lima ocorrentes em dois remanescentes de Floresta Atlântica no Estado do Rio de Janeiro. Foram amostradas árvores de diâmetro semelhante retas e sem defeitos aparentes. Os resultados obtidos comprovam estatisticamente a ocorrência de variação intraspecífica na estrutura anatômica da madeira. Os caracteres qualitativos mantiveram-se constantes, enquanto os quantitativos variaram, sendo os significativos, de acordo com o teste t de Student, a freqüencia, comprimento e diâmetro dos elementos vasos, o comprimento e espessura da parede das fibras, a freqüência e largura dos raios. A análise dos componentes principais, utilizando características anatômicas quantitativas ordenou as duas populações separadamente. O eixo I responde por 33% da variância total principalmente pela relação positiva do diâmetro do elemento de vaso, enquanto o eixo II responde por 20% da variância total, principalmente pelo comprimento das fibras.This study compares distinct populations of Pseudopiptadenia contorta (DC G.P. Lewis & M.P. Lima occurring in two remnants of Atlantic rain forest in Rio de Janeiro state. Trees with similar diameters and with no apparent defects were selected. The results confirm intraspecific variation in wood anatomy. Qualitative features do not change, while according to the Student t test quantitative features showed significant differences in vessel-element frequency, width, and length, fiber length and wall thickness, and ray frequency and width. Principal component analysis showed two separate populations. Factor 1 explains 33% of the total variance, mainly due to the positive relationship of vessel-element tangential diameter; factor 2 explains 20% of the total variance, mainly due to fiber length.

  1. A novel rain removal technology based on video image

    Science.gov (United States)

    Liu, Shuo; Piao, Yan

    2016-11-01

    Due to the effect of bad weather conditions, it often conducts visual distortions on images for outdoor vision systems. Rain is one specific example of bad weather. Generally, rain streak is small and falls at high velocity. Traditional rain removal methods often cause blued visual effect. In addition, there is high time complexity. Moreover, some rain streaks are still in the de-rained image. Based on the characteristics of rain streak, a novel rain removal technology is proposed. The proposed method is not only removing the rain streak effectively, but also retaining much detail information. The experiments show that the proposed method outperform traditional rain removal methods. It can be widely used in intelligent traffic, civilian surveillance and national security so on.

  2. Multidimensional modeling of coronal rain dynamics

    CERN Document Server

    Fang, X; Keppens, R

    2013-01-01

    We present the first multidimensional, magnetohydrodynamic simulations which capture the initial formation and the long-term sustainment of the enigmatic coronal rain phenomenon. We demonstrate how thermal instability can induce a spectacular display of in-situ forming blob-like condensations which then start their intimate ballet on top of initially linear force-free arcades. Our magnetic arcades host chromospheric, transition region, and coronal plasma. Following coronal rain dynamics for over 80 minutes physical time, we collect enough statistics to quantify blob widths, lengths, velocity distributions, and other characteristics which directly match with modern observational knowledge. Our virtual coronal rain displays the deformation of blobs into $V$-shaped like features, interactions of blobs due to mostly pressure-mediated levitations, and gives the first views on blobs which evaporate in situ, or get siphoned over the apex of the background arcade. Our simulations pave the way for systematic surveys o...

  3. Propagating Characteristics of Pulsed Laser in Rain

    Directory of Open Access Journals (Sweden)

    Jing Guo

    2015-01-01

    Full Text Available To understand the performance of laser ranging system under the rain weather condition, we need to know the propagating characteristics of laser pulse in rain. In this paper, the absorption and attenuation coefficients were calculated based on the scattering theories in discrete stochastic media, and the propagating characteristics of laser pulse in rain were simulated and analyzed using Monte-Carlo method. Some simulation results were verified by experiments, and the simulation results are well matched with the experimental data, with the maximal deviation not less than 7.5%. The results indicated that the propagating laser beam would be attenuated and distorted due to the scattering and absorption of raindrops, and the energy attenuation and pulse shape distortion strongly depended on the laser pulse widths.

  4. Seed dispersal limitations shift over time in tropical forest restoration.

    Science.gov (United States)

    Reid, J Leighton; Holl, Karen D; Zahawi, Rakan A

    2015-06-01

    Past studies have shown that tropical forest regeneration on degraded farmlands is initially limited by lack of seed dispersal, but few studies have tracked changes in abundance and composition of seed rain past the first few years after land abandonment. We measured seed rain for 12 months in 10 6-9-year-old restoration sites and five mature, reference forests in southern Costa Rica in order to learn (1) if seed rain limitation persists past the first few years of regeneration; (2) how restoration treatments influence seed community structure and composition; and (3) whether seed rain limitation is contingent on landscape context. Each restoration site contained three 0.25-ha treatment plots: (1) a naturally regenerating control, (2) tree islands, and (3) a mixed-species tree plantation. Sites spanned a deforestation gradient with 9-89% forest area within 500 m around the treatment plots. Contrary to previous studies, we found that tree seeds were abundant and ubiquitous across all treatment plots (585.1 ± 142.0 seeds · m(-2) · yr(-1) [mean ± SE]), indicating that lack of seed rain ceased to limit forest regeneration within the first decade of recovery. Pioneer trees and shrubs comprised the vast majority of seeds, but compositional differences between restoration sites and reference forests were driven by rarer, large-seeded species. Large, animal-dispersed tree seeds were more abundant in tree islands (4.6 ± 2.9 seeds · m(-2) · yr(-1)) and plantations (5.8 ± 3.0 seeds · m(-2) · yr(-1)) than control plots (0.2 ± 0.1 seeds · m(-2) · yr(-1)), contributing to greater tree species richness in actively restored plots. Planted tree species accounted for seeds. We found little evidence for landscape forest cover effects on seed rain, consistent with previous studies. We conclude that seed rain limitation shifted from an initial, complete lack of tree seeds to a specific limitation on large-seeded, mature forest species over the first decade. Although total

  5. Forest Histories & Forest Futures

    OpenAIRE

    Whitlock, Cathy

    2009-01-01

    The climate changes projected for the future will have significant consequences for forest ecosystems and our ability to manage them. It is reasonable to ask: Are there historical precedents that help us understand what might happen in the future or are historical perspectives becoming irrelevant? What synergisms and feedbacks might be expected between rapidly changing climate and land–use in different settings, especially at the wildland–urban interface? What lessons from the past might help...

  6. Forest Resources

    Energy Technology Data Exchange (ETDEWEB)

    None

    2016-06-01

    Forest biomass is an abundant biomass feedstock that complements the conventional forest use of wood for paper and wood materials. It may be utilized for bioenergy production, such as heat and electricity, as well as for biofuels and a variety of bioproducts, such as industrial chemicals, textiles, and other renewable materials. The resources within the 2016 Billion-Ton Report include primary forest resources, which are taken directly from timberland-only forests, removed from the land, and taken to the roadside.

  7. Strong carbon sink of monsoon tropical seasonal forest in Southern Vietnam

    Science.gov (United States)

    Deshcherevskaya, Olga; Anichkin, Alexandr; Avilov, Vitaly; Duy Dinh, Ba; Luu Do, Phong; Huan Tran, Cong; Kurbatova, Julia

    2014-05-01

    Comparison between anthropogenic emission of carbon dioxide and atmospheric carbon pool change displays that only half of emitted CO2 remains in air, leaving so-called 'missing sink' of carbon. Terrestrial biosphere and ocean accumulate each about a half of this value (Gifford, 1994). Forest biomes play the decisive role in 'missing sink' because of high primary production flux and large carbon pool. Almost all the sink belongs to boreal forests, because warming and wetting coupled with increasing CO2 concentration and N deposition gives more favorable conditions for boreal ecosystems. On the contrary, tropical climate changes effect on forests is not obvious, probably cause more drought conditions; tropical forests suffer from 1.2 % per year area reduction and disturbance. Whether primary tropical forests act as carbon sink is still unclear. Biomass inventories at 146 forest plots across all the tropics in 1987-1997 revealed low carbon sink in humid forests biomass of 49 (29-66; 95% C.I.) g C m-2 year-1 on average (Malhi, 2010). Estimates for undisturbed African forests are close to global (Ciais et al., 2008). Eddy covariance (EC) observations with weak-turbulence correction in Amazonia reveal near-zero or small negative (i.e. sink) balance (Clark, 2004). Three EC sites in SE Asia primary forests give near-zero balance again (Saigusa et al., 2008; Kosugi et al., 2012). There are two main groups of explanations of moderate tropical carbon sink: (a) recovering of large-disturbance in the past or (b) response to current atmospheric changes: increase of CO2 concentration and/or climate change. So, strong carbon accumulation is not common for primary tropical forests. In this context sink of 402 g C m-2 in 2012 at EC station of Nam Cat Tien (NCT), Southern Vietnam (N 11°27', E 107°24', 134 m a.s.l.) in primary monsoon tropical forest looks questionably. EC instrument set at NCT consists of CSAT3 sonic anemometer and LI-7500A open-path gas analyzer. All the standard

  8. Recent pollen spectra from the deciduous and coniferous-deciduous forests of Northeastern Minnesota: a study in pollen dispersal

    NARCIS (Netherlands)

    Janssen, C.R.

    1966-01-01

    Pollen samples were taken along nine transects across local vegetational belts bordering bogs or ponds in overall deciduous and coniferous-deciduous forest regions. Three types of pollen rain are distinguished: local, extralocal, and regional. Local pollen rain is derived from plants that grow at or

  9. Disdrometer and Tipping Bucket Rain Gauge Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Bartholomew. MJ

    2009-12-01

    The Distromet disdrometer model RD-80 and NovaLynx tipping bucket rain gauge model 260-2500E-12 are two devices deployed a few meters apart to measure the character and amount of liquid precipitation. The main purpose of the disdrometer is to measure drop size distribution, which it does over 20 size classes from 0.3 mm to 5.4 mm. The data from both instruments can be used to determine rain rate. The disdrometer results can also be used to infer several properties including drop number density, radar reflectivity, liquid water content, and energy flux. Two coefficients, N0 and Λ, from an exponential fit between drop diameter and drop number density, are routinely calculated. Data are collected once a minute. The instruments make completely different kinds of measurements. Rain that falls on the disdrometer sensor moves a plunger on a vertical axis. The disdrometer transforms the plunger motion into electrical impulses whose strength is proportional to drop diameter. The rain gauge is the conventional tipping bucket type. Each tip collects an amount equivalent to 0.01 in. of water, and each tip is counted by a data acquisition system anchored by a Campbell CR1000 data logger.

  10. Acid Rain. Teacher's Guide. LHS GEMS.

    Science.gov (United States)

    Hocking, Colin; Barber, Jacqueline; Coonrod, Jan

    This teacher's guide presents a unit on acid rain and introduces hands-on activities for sixth through eighth grade students. In each unit, students act as real scientists and gather evidence by using science process skills such as observing, measuring and recording data, classifying, role playing, problem solving, critical thinking, synthesizing…

  11. Acid Rain Materials for Classroom Use.

    Science.gov (United States)

    Factor, Lance; Kooser, Robert G.

    This booklet contains three separate papers suitable for use in an advanced high school or college chemistry course. The first paper provides background information on acids and bases. The second paper provides additional background information, focusing on certain aspects of atmospheric chemistry as it relates to the acid rain problem. An attempt…

  12. Acid Rain: A Student's First Sourcebook.

    Science.gov (United States)

    Kyle, Beth Ann; And Others

    The purpose of this guide is to help students better understand the science, citizen action, and research issues that are part of the acid rain problem. The guide is designed for students in grades 4-8 and their teachers. Following an introduction, the first seven sections are informative in nature. They include: (1) "Observations about Acidity";…

  13. Forest People, Two Countries and One Continent: What Empirical Connections?

    Science.gov (United States)

    Ifegbesan, Ayodeji; Pendlebury, Shirley; Annegarn, Harold

    2009-01-01

    Studies have revealed that sub-Sahara African forest resources are decreasing at an alarming rate. Widely acknowledged too is a growing body of empirical evidence which suggests that understanding people's views are important to forest conservation. But few are the current studies that capture cross-national perspectives. This study explores the…

  14. Devastating decline of forest elephants in Central Africa

    NARCIS (Netherlands)

    F. Maisels; S. Strindberg; S. Blake; G. Wittemyer; J. Hart; E.A. Williamson; R.G. Aba'a; F. Amsini; R.D. Ambahe; P.C. Bakabana; T.C. Hicks; R.E. Bayogo; M. Bechem; R.L. Beyers; A.N. Bezangoye; P. Boundja; N. Bout; M.E. Akou; L.E. Bene; B. Fosso; E. Greengrass; F. Grossmann; C. Ikamba-Nkulu; O. Ilambu; B.I. Inogwabini; F. Iyenguet; F. Kiminou; M. Kokangoye; D. Kujirakwinja; S. Latour; I. Liengola; Q. Mackaya; J. Madidi; B. Madzoke; C. Makoumbou; G.A. Malanda; R. Malonga; O. Mbani; V.A. Mbendzo; E. Ambassa; A. Ekinde; Y. Mihindou; B.J. Morgan; P. Motsaba; G. Moukala; A. Mounguengui; B.S. Mowawa; C. Ndzai; S. Nixon; P. Nkumu; F. Nzolani; L. Pintea; A. Plumptre; H. Rainey; B.B. de Semboli; A. Serckx; E. Stokes; A. Turkalo; H. Vanleeuwe; A. Vosper; Y. Warren

    2013-01-01

    African forest elephants- taxonomically and functionally unique-are being poached at accelerating rates, but we lack range-wide information on the repercussions. Analysis of the largest survey dataset ever assembled for forest elephants (80 foot-surveys; covering 13,000 km; 91,600 person-days of fie

  15. Forest climbing plants of West Africa: diversity, ecology and management

    NARCIS (Netherlands)

    Bongers, F.J.J.M.; Parren, M.P.E.; Traoré, D.

    2005-01-01

    Climbing plants, including lianas, represent a fascinating component of the ecology of tropical forests. This book focuses on the climbing plants of West African forests. Based on original research, it presents information on the flora (including a checklist), diversity (with overviews at several le

  16. Forest sleuths stalk a killer

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, F.A.

    This article describes the impact of air pollution on the San Bernardino National Forest near Los Angeles. Ponderosa and Jeffry pines, damaged as a result of ozone have been replaced by increasing numbers of white fir and incense cedar. Ozone-damaged trees have been less able to recover during years favorable for growth and have been attacked aggressively by dendroctonus beetles. It is not yet known what the change in species composition will mean to wildlife such as squirrels; if squirrels and other rodents are affected, hawks and other predators will also be affected. Researchers are considering these questions and, further, the problem of combinations of ozone and acid rain.

  17. The importance of seed mass for early regeneration in tropical forest: a review

    NARCIS (Netherlands)

    Rose, S.A.; Poorter, L.

    2003-01-01

    Seed mass is an important component of the shade tolerance of rain forest tree species. Using a metaanalysis this article evaluates till what extent seed mass affects the survival, initial size, and growth of seedlings in light environments that are typical of forest gaps and understory

  18. Does functional trait diversity predict aboveground biomass and productivity of tropical forests? Testing three alternative hypotheses

    NARCIS (Netherlands)

    Finegan, B.; Pena Claros, M.; Silva de Oliveira, A.; Ascarrunz, N.; Bret-Harte, M.S.; Carreño Rocabado, I.G.; Casanoves, F.; Diaz, S.; Eguiguren Velepucha, P.; Fernandez, F.; Licona, J.C.; Lorenzo, L.; Salgado Negret, B.; Vaz, M.; Poorter, L.

    2014-01-01

    1. Tropical forests are globally important, but it is not clear whether biodiversity enhances carbon storage and sequestration in them. We tested this relationship focusing on components of functional trait biodiversity as predictors. 2. Data are presented for three rain forests in Bolivia, Brazil a

  19. Does functional trait diversity predict aboveground biomass and productivity of tropical forests? Testing three alternative hypotheses

    NARCIS (Netherlands)

    Finegan, B.; Peña Claros, M.; Oliviera, de A.; Alarcón, A.; Ascarrunz, N.; Bret-Harte, M.S.; Carreño-Rocabado, G.; Casanoves, F.; Díaz, S.; Eguiguren Velepucha, P.; Fernandez, F.; Licona, J.C.; Lorenzo, L.; Salgado Negret, B.; Vaz, M.; Poorter, L.

    2015-01-01

    Tropical forests are globally important, but it is not clear whether biodiversity enhances carbon storage and sequestration in them. We tested this relationship focusing on components of functional trait biodiversity as predictors. Data are presented for three rain forests in Bolivia, Brazil and Cos

  20. Seasonal variation in soil and plant water potentials in a Bolivian tropical moist and dry forest

    NARCIS (Netherlands)

    Markesteijn, L.; Iraipi, J.; Bongers, F.; Poorter, L.

    2010-01-01

    We determined seasonal variation in soil matric potentials (¿soil) along a topographical gradient and with soil depth in a Bolivian tropical dry (1160 mm y-1 rain) and moist forest (1580 mm y-1). In each forest we analysed the effect of drought on predawn leaf water potentials (¿pd) and drought resp

  1. Climate change as a confounding factor in reversibility of acidification: RAIN and CLIMEX projects

    Directory of Open Access Journals (Sweden)

    R. F. Wright

    2001-01-01

    Full Text Available The RAIN and CLIMEX experiments at Risdalsheia, southernmost Norway, together cover 17 years (1984-2000 of whole-catchment manipulation of acid deposition and climate. A 1200 m2 roof placed over the forest canopy at KIM catchment excluded about 80% of ambient acid deposition; clean rain was sprinkled under the roof. A climate change treatment (3.7°C increase in air temperature and increase in air carbon dioxide concentrations to 560 ppmv was superimposed on the clean rain treatment for four years (1995-1998. Sea-salt inputs and temperature are climate-related factors that influence water chemistry and can confound long-term trends caused by changes in deposition of sulphur and nitrogen. The RAIN and CLIMEX experiments at Risdalsheia provided direct experimental data that allow quantitative assessment of these factors. Run-off chemistry responded rapidly to the decreased acid deposition. Sulphate concentrations decreased by 50% within three years; nitrate and ammonium concentrations decreased to new steady-state levels within the first year. Acid neutralising capacity increased and hydrogen ion and inorganic aluminium decreased. Similar recovery from acidification was also observed at the reference catchment, ROLF, in response to the general 50% reduction in sulphate deposition over southern Norway in the late 1980s and 1990s. Variations in sea-salt deposition caused large variations in run-off chemistry at the reference catchment ROLF and the year-to-year noise in acid neutralising capacity was as large as the overall trend over the period. These variations were absent at KIM catchment because the sea-salt inputs were held constant over the entire 17 years of the clean rain treatment. The climate change experiment at KIM catchment resulted in increased leaching of inorganic nitrogen, probably due to increased mineralisation and nitrification rates in the soils. Keywords: acid deposition, global change, water, soil, catchment, experiment, Norway.

  2. Urban Water-Quality Management. Rain Garden Plants

    OpenAIRE

    French, Sue (Sue C.); Fox, Laurie; Andruczyk, Mike; Gilland, Traci; Swanson, Lynette

    2009-01-01

    A rain garden is a landscaped area specially designed to collect rainfall and storm-water runoff. The plants and soil in the rain garden clean pollutants from the water as it seeps into the ground and evaporates back into the atmosphere. For a rain garden to work, plants must be selected, installed, and maintained properly.

  3. 40 CFR 76.3 - General Acid Rain Program provisions.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false General Acid Rain Program provisions. 76.3 Section 76.3 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.3 General Acid Rain Program...

  4. The evolution of African plant diversity

    Directory of Open Access Journals (Sweden)

    Hans Peter Linder

    2014-07-01

    Full Text Available Sub-Saharan Africa includes some 45,000 plant species. The spatial patterns of this diversity have been well explored. We can group the species into a set of biogeographical regions (largely co-incident with regions defined for terrestrial vertebrate groups. Furthermore, we know that the diversity is unevenly distributed, with southern Africa (especially the south-western tip disproportionally species rich, while the West African interior is disproportionally species poor. However, the origins of this diversity have only been explored for two anomalous African Floras (the Tropic-alpine Flora and the Cape Flora, whereas the origins of the diversity of the other floras are still unknown. Here I argue that six floras, with distinct geographical centres, different extra-African affinities, ages of radiation and radiation rates, can be delimited: the Austro-temperate, Tropic-alpine, Lowland forest, Tropic-montane, Savanna and Arid Floras. The oldest flora may be the Lowland forest Flora, and the most recent is the Tropic-alpine, which probably evolved during the Plio-Pleistocene on the summits of the East Africa volcanoes. My results suggest that the most rapidly radiating flora is the Austro-temperate Flora, while the other floras are all diversifying at more or less the same rate, this is also consistent with the current massive species richness in this flora (about half of the African species richness. The Austro-temperate Flora appears to be related to the floras of the other southern continents, the Tropic-alpine Flora to that of the Northern Hemisphere, and the four tropical floras to the tropical regions of the other continents, consistent with the theory of phylogenetic niche conservatism. Current African diversity may be the result of the sequential adding of new floras to the continent. Possibly the species poverty especially of the Lowland forest Flora may be the result of the spread of C4 grasslands and associated regular fires.

  5. A Stochastic Integer Programming Model for Minimizing Cost in the Use of Rain Water Collectors for Firefighting

    Directory of Open Access Journals (Sweden)

    Luis A. Rivera-Morales

    2014-01-01

    Full Text Available In this paper we propose a stochastic integer programming optimization model to determine the optimal location and number of rain water collectors (RWCs for forest firefighting. The objective is to minimize expected total cost to control forest fires. The model is tested using a real case and several additional realistic scenarios. The impact on the solution of varying the limit on the number of RWCs, the RWC water capacity, the aircraft capacity, the water demands, and the aircraft operating cost is explored. Some observations are that the objective value improves with larger RWCs and with the use of aircraft with greater capacity.

  6. Pollution problem: acid rain and beekeeping

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, B.

    1979-11-01

    Some of the problems caused by acid rain are presented with emphasis on the effects on bees, especially in the Northeast. Scientists believe that rain east of the Mississippi is below 5.6 and average Northeastern rainfall is now down to pH 4. Trace minerals are being leached out of the soils and nectar that lacks calcium is being passed by when the bees forage. The first plants to show the effects will be the wild varieties of the legumes, such as clover. This leaves only plants on the extreme end of the acid scale such as the blueberry for bee forage. This leads to the side effect of the movement of calcium in nectar which will be restricted due to a lack of calcium-lime.

  7. Heart Disease and African Americans

    Science.gov (United States)

    ... Minority Population Profiles > Black/African American > Heart Disease Heart Disease and African Americans Although African American adults are ... were 30 percent more likely to die from heart disease than non-Hispanic whites. African American women are ...

  8. Atmospheric oxidation capacity sustained by a tropical forest

    NARCIS (Netherlands)

    Lelieveld, J.; Butler, T.; Crowley, J.N.; Dillon, T.J.; Fischer, H.; Ganzeveld, L.N.; Harder, H.; Lawrence, M.G.; Martinez, M.; Taraborelli, D.; Williams, J.

    2008-01-01

    Terrestrial vegetation, especially tropical rain forest, releases vast quantities of volatile organic compounds (VOCs) to the atmosphere1, 2, 3, which are removed by oxidation reactions and deposition of reaction products4, 5, 6. The oxidation is mainly initiated by hydroxyl radicals (OH), primarily

  9. Floristic observation on forest types in Western Suriname. II

    NARCIS (Netherlands)

    Maas, P.J.M.

    1971-01-01

    H. Rain forest at Kamisa falls (Niekerie R., west bank) (see table 8) 7 plots of 1000 m² and 21 plots of 100 m², total area 9100 m². – Number of species: ca 110. – Soil: brown to grey, loamy sand, occasionally with ferrite gravel. – Dominant species: Dicorynia guianensis (basralokus). – Shrub layer:

  10. Trees of Life: Saving Tropical Forests and Their Biological Wealth.

    Science.gov (United States)

    Miller, Kenton; Tangley, Laura

    Staggering statistics and dramatic headlines about the destruction of rain forests, the world's richest ecosystems, are only a small part of the devastating story of global deforestation. This volume provides comprehensive coverage of this complex scientific and political catastrophe-in-the-making and examines the costs and the consequences, in…

  11. Convergence across biomes to a common rain-use efficiency.

    Science.gov (United States)

    Huxman, Travis E; Smith, Melinda D; Fay, Philip A; Knapp, Alan K; Shaw, M Rebecca; Loik, Michael E; Smith, Stanley D; Tissue, David T; Zak, John C; Weltzin, Jake F; Pockman, William T; Sala, Osvaldo E; Haddad, Brent M; Harte, John; Koch, George W; Schwinning, Susan; Small, Eric E; Williams, David G

    2004-06-10

    Water availability limits plant growth and production in almost all terrestrial ecosystems. However, biomes differ substantially in sensitivity of aboveground net primary production (ANPP) to between-year variation in precipitation. Average rain-use efficiency (RUE; ANPP/precipitation) also varies between biomes, supposedly because of differences in vegetation structure and/or biogeochemical constraints. Here we show that RUE decreases across biomes as mean annual precipitation increases. However, during the driest years at each site, there is convergence to a common maximum RUE (RUE(max)) that is typical of arid ecosystems. RUE(max) was also identified by experimentally altering the degree of limitation by water and other resources. Thus, in years when water is most limiting, deserts, grasslands and forests all exhibit the same rate of biomass production per unit rainfall, despite differences in physiognomy and site-level RUE. Global climate models predict increased between-year variability in precipitation, more frequent extreme drought events, and changes in temperature. Forecasts of future ecosystem behaviour should take into account this convergent feature of terrestrial biomes.

  12. Acid rain in Europe and the United States: an update

    Energy Technology Data Exchange (ETDEWEB)

    Fredric C. Menz; Hans M. Seip [Clarkson University, Potsdam, NY (US). Bertrand Snell Hall, School of Business

    2004-08-01

    This paper discusses the evolution of science and policies to control acid rain in Europe and the United States over the past several decades. Acid rain gained prominence in the late 1960s because of its perceived effects on ecosystem integrity. Extensive research efforts in both Europe and the United States, however, have concluded that the effects of acid rain - at least those on terrestrial ecosystems - were less serious than originally believed. More recently, interest in controlling acid rain precursors stems primarily from health concerns, particularly their effects in the form of fine particulate matter. The paper discusses the emergence of acid rain as an environmental concern, scientific evidence about the effects of acidic deposition on natural ecosystems, US and European acid rain control policies, studies of the costs and benefits of reducing acid rain, and different policy contexts in Europe and the United States.

  13. Rain Sensor with Stacked Light Waveguide Having Tilted Air Gap

    Directory of Open Access Journals (Sweden)

    Kyoo Nam Choi

    2014-01-01

    Full Text Available Vehicle sensor to detect rain drop on and above waveguide utilizing light deflection and scattering was realized, keeping wide sensing coverage and sensitivity to detect mist accumulation. Proposed sensor structure under stacked light wave guide consisted of light blocking fixture surrounding photodetector and adjacent light source. Tilted air gap between stacked light waveguide and light blocking fixture played major role to increase sensitivity and to enhance linearity. This sensor structure eliminated complex collimating optics, while keeping wide sensing coverage using simple geometry. Detection algorithm based on time-to-intensity transformation process was used to convert raining intensity into countable raining process. Experimental result inside simulated rain chamber showed distinct different response between light rain and normal rain. Application as automobile rain sensor is expected.

  14. Chemical properties of rain events during the AMMA campaign: an evidence of dust and biogenic influence in the convective systems

    Directory of Open Access Journals (Sweden)

    K. Desboeufs

    2010-06-01

    Full Text Available This paper documents the chemical composition of 7 rain events associated with mesoscale convective systems sampled at the supersite of Banizoumbou, Niger, during the first special observation periods (June–July 2006 of the African Monsoon Multidisciplinary Analyses (AMMA experiment. Time-resolved rain sampling was performed in order to discriminate the local dust scavenged at the beginning of rain event from the aerosol particles incorporated in the cloud at the end of the rain. The total elemental composition is dominated by Al, Si, Fe and Ca, indicating a high influence of dust and limited marine or anthropogenic contribution. After the aerosol wash-out, the elemental concentrations normalized to Al and the microscopic observations of diatoms, a tracer of the Bodélé depression, both indicate that the total elemental composition of rainwater is controlled by dust originating from North-Eastern Saharan sources and probably incorporated in the convective cloud from the Harmattan layer. The low variability of the rain composition over the measurement period indicates a regional and temporal homogeneity of dust composition in the Harmattan layer. In the dissolved phase, the dominant anions are nitrate (NO3, sulphate (SO42− and chloride (Cl. However, between June and July we observe an increasing contribution of the organic anions (formate, acetate, oxalate associated with biogenic emissions to the total ion composition. These results confirm the large influence of biogenic emissions on the rain composition over Sahel during the wet season. The paper concludes on the capacity of mesoscale convective systems to carry simultaneously dust and biogenic compounds originating from different locations and depose them jointly. It also discusses the potential biogeochemical impact of such a phenomenon.

  15. Rain-Flow and Reverse Rain-Flow Counting Method for the Compilation of Fatigue Load Spectrum

    Institute of Scientific and Technical Information of China (English)

    宋玉普; 李朝阳; 王立成

    2001-01-01

    The rain-flow counting method is widely used to compile the fatigue load spectrum. The second stage counting of the rain-flow method is a troublesome process. In order to overcome this drawback, the rain-flow and reverse rain-flow counting method is proposed in this paper. In this counting method, the rule for counting of the rain-flow method is modified, so that the sequence of load-time need not be adjusted. This is a valid and useful method to count cycles and compile the load spectrum and it can be widely used in ocean engineering.

  16. Productivity of forest birds at Hakalau Forest NWR

    Science.gov (United States)

    Paxton, Eben; Cummins, George C; Kendall, Steven J.

    2014-01-01

    Hawai‘i has some of the most endangered avian species in the world, which face numerous threats from habitat loss, disease, climate change, and introduced species. This report details the results of a two-year productivity study of all forest bird species at Hakalau National Wildlife Refuge, Hawai‘i Island. We found and monitored nests from seven native species and three common non-native species of forest birds at three sites across the refuge. In addition to gathering important baseline information on productivity of forest birds, we examined differences in productivity between years, sites, and as a function of nest height. The weather differed greatly between the two years, with much more rain occurring in 2014. The daily survival rate (DSR) of nests was found to have an inverse relationship with the amount of rainfall, and accordingly was much lower in 2014 compared to 2013. Nest success was lower at a regenerating forest site compared with mature rainforest, indicating negative environmental factors affecting nest success may be exacerbated in reforested areas which have lower canopies. Nest success was also impacted by nest height, with a positive relationship in the drier 2013, and a negative relationship in 2014 for the canopy nesting honeycreepers. The large difference in weather and DSR between years illustrates the need for long term demographic studies that can capture the vital rates of this community of birds.

  17. Depression and African Americans

    Science.gov (United States)

    ... You are here Home » Depression And African Americans Depression And African Americans Not “Just the Blues” Clinical ... or spiritual communities. Commonly Asked Questions about Clinical Depression How do I get help for clinical depression? ...

  18. The relationship between the Guinea Highlands and the West African offshore rainfall maximum

    Science.gov (United States)

    Hamilton, H. L.; Young, G. S.; Evans, J. L.; Fuentes, J. D.; Núñez Ocasio, K. M.

    2017-01-01

    Satellite rainfall estimates reveal a consistent rainfall maximum off the West African coast during the monsoon season. An analysis of 16 years of rainfall in the monsoon season is conducted to explore the drivers of such copious amounts of rainfall. Composites of daily rainfall and midlevel meridional winds centered on the days with maximum rainfall show that the day with the heaviest rainfall follows the strongest midlevel northerlies but coincides with peak low-level moisture convergence. Rain type composites show that convective rain dominates the study region. The dominant contribution to the offshore rainfall maximum is convective development driven by the enhancement of upslope winds near the Guinea Highlands. The enhancement in the upslope flow is closely related to African easterly waves propagating off the continent that generate low-level cyclonic vorticity and convergence. Numerical simulations reproduce the observed rainfall maximum and indicate that it weakens if the African topography is reduced.

  19. Florística e estrutura de comunidades vegetais em uma cronoseqüência de Floresta Atlântica no Estado do Paraná, Brasil Floristics and structure of plant communities along a chronosequence in the Atlantic Rain Forest of Paraná State, Brazil

    Directory of Open Access Journals (Sweden)

    Dieter Liebsch

    2007-12-01

    Full Text Available Descrevemos a estrutura do estrato arbóreo de três sítios de Floresta Atlântica no litoral do Paraná, objetivando detectar diferenças estruturais gerais e nas populações ao longo do processo sucessional, visando subsidiar futuros planos de recomposição da vegetação. O estudo foi realizado na Reserva Natural Rio Cachoeira, onde foram escolhidos três sítios, cujos históricos indicavam a ocorrência de corte da vegetação há 20 anos, 80 anos e 120 anos. O sítio com 20 anos apresentou os menores valores de riqueza, diversidade, área basal e volume. O sítio com 80 anos apresentou os maiores valores de densidade e riqueza. No sítio com 120 anos foi observado o maior valor de diversidade, equabilidade e volume. Observaram-se algumas diferenças significativas, em termos de diversidade, área basal e volume entre os sítios em diferentes estádios. Comparações das estruturas de populações de espécies que ocorriam em mais de um sítio não mostraram grandes diferenças. Por outro lado, as características das espécies exclusivas de cada sítio influenciaram nas diferenças observadas nos três sítios.We describe the tree structure of three Atlantic Forest fragments on the coast of Paraná, in order to detect differences in community structure throughout the succession process and to support future vegetation restoration projects. The study area was the Reserva Natural Rio Cachoeira, where three sites were chosen based on length of time since the last manmade disturbance (mostly agriculture and lodging; these were, respectively, 20-, 80- and 120-year-old forests. The 20-year-old forest had the lowest richness, diversity, basal area and volume. The 80-year-old forest had the highest density and richness. The 120-year-old forest had the highest diversity, equitability and volume. Diversity, basal area and volume were significantly different among the three sites. There were no important differences among structures of populations

  20. Restoring forests

    DEFF Research Database (Denmark)

    Jacobs, Douglass F.; Oliet, Juan A.; Aronson, James;

    2015-01-01

    Forest loss and degradation is occurring at high rates but humankind is experiencing historical momentum that favors forest restoration. Approaches to restoration may follow various paradigms depending on stakeholder objectives, regional climate, or the degree of site degradation. The vast amount...

  1. Linguistic Imperialism: African Perspectives.

    Science.gov (United States)

    Phillipson, Robert

    1996-01-01

    Responds to an article on aspects of African language policy and discusses the following issues: multilingualism and monolingualism, proposed changes in language policy from the Organization for African Unity and South African initiatives, the language of literature, bilingual education, and whose interests English-language teaching is serving.…

  2. Growth rate of a terra firme rain forest in Brazilian Amazonia over an eight-year period in response to logging Crescimento de uma floresta de terra firme na Amazônia brasileira em um período de oito anos após a exploração florestal

    Directory of Open Access Journals (Sweden)

    João Olegário Pereira de Carvalho

    2004-01-01

    Full Text Available This paper deals with growth rates of trees > 5cm dbh over an eight-year period from 257 species at the Tapajós National Forest. The discussion is centred on the behaviour of the forest after logging. Permanent sample plots were established in 1981 and measured at the first time. The area was logged in 1982. Measurements after logging occurred in 1983, 1987 and 1989. Considering all species together, diameter increment was similar for both intensities of logging until five years after logging. Light-demanding species showed significantly higher growth rates than shade-tolerant species in the logged forest, with greater increment in the heavier treatment intensity. Commercial species also had higher growth rates in the heavier logged area, although those were significantly different only in the period from one to five years after logging. In the undisturbed forest, growth rates increased with increasing dbh size. At species level, growth rate varied between and within treatments, as well as between trees within species, depending mainly on degree of canopy opening. The logging favoured the growth of commercial species, chiefly the light-demanders. Therefore, if the same growth conditions continue being given, for example by silvicultural treatments, to those species of commercial interest, the forest would reach a stock available for harvesting around year 30 after logging. However, the high variation in increment rates indicates that an eight-year period is not sufficient to allow predictions on cutting cycles or polycyclic management systems for the study forest.É analisado o crescimento de 257 espécies arbóreas, considerando indivíduos com DAP > 5cm, na Floresta Nacional do Tapajós, em um período de oito anos. Em 1981 foram estabelecidas parcelas permanentes, e medidas pela primeira vez. Em 1982 a área foi explorada. Medições após a exploração foram realizadas em 1983, 1987 e 1989. Considerando todas as espécies juntas, o

  3. Measurement and modeling of rainfall interception by two differently aged secondary forests in upland eastern Madagascar

    Science.gov (United States)

    Prasad Ghimire, Chandra; Adrian Bruijnzeel, L.; Lubczynski, Maciek W.; Ravelona, Maafaka; Zwartendijk, Bob W.; van Meerveld, H. J. (Ilja)

    2017-02-01

    Secondary forests occupy a larger area than old-growth rain forests in many tropical regions but their hydrological functioning is still poorly understood. In particular, little is known about the various components of evapotranspiration in these possibly vigorously regenerating forests. This paper reports on a comparison of measured and modeled canopy interception losses (I) from a semi-mature (ca. 20 years) and a young (5-7 years) secondary forest in the lower montane rain forest zone of eastern Madagascar. Measurements of gross rainfall (P), throughfall (Tf), and stemflow (Sf) were made in both forests for one year (October 2014-September 2015) and the revised analytical model of Gash et al. (1995) was tested for the first time in a tropical secondary forest setting. Overall measured Tf, Sf and derived I in the semi-mature forest were 71.0%, 1.7% and 27.3% of incident P, respectively. Corresponding values for the young forest were 75.8%, 6.2% and 18.0%. The high Sf for the young forest reflects the strongly upward thrusting habit of the branches of the dominant species (Psiadia altissima), which favours funneling of P. The value of I for the semi-mature forest is similar to values reported for old-growth tropical lower montane rain forests elsewhere but I for the younger forest is higher than reported for similarly aged tropical lowland forests. These findings can be explained largely by the prevailing low rainfall intensities and the frequent occurrence of small rainfall events. The revised analytical model was able to reproduce measured cumulative I at the two sites accurately and succeeded in capturing the variability in I associated with the seasonal variability in rainfall intensity, provided that Tf-based values for the average wet-canopy evaporation rates were used instead of values derived with the Penman-Monteith equation.

  4. Sobrevivência de espécies arbóreas plantadas em clareiras causadas pela colheita de madeira em uma floresta de terra firme no município de Paragominas na Amazônia brasileira Survival of seedlings planted in gaps after harvesting in a terra firme rain forest in Paragominas region in the Brazilian Amazonia

    Directory of Open Access Journals (Sweden)

    Jaqueline Macêdo Gomes

    2010-03-01

    Full Text Available Analisou-se a sobrevivência de mudas plantadas em 400 clareiras causadas por exploração florestal de impacto reduzido, em floresta de terra firme na Amazônia Oriental. Foram plantadas 3.818 mudas de 17 espécies, das quais apenas Schizolobium amazonicum não ocorre na área de estudo. A distância entre as mudas plantadas foi de aproximadamente 5m. As avaliações ocorreram em 2005 e 2006. Com base na sobrevivência das mudas aos 11 meses após o plantio, as espécies indicadas para o enriquecimento de clareiras são: Schizolobium amazonicum, Cedrela odorata, Jacaranda copaia, Manilkara huberi, Astronium gracile, Pouteria bilocularis, Tabebuia impetiginosa,Pseudopiptadenia suaveolens, Cordia goeldiana, Parkia gigantocarpa, Simarouba amara, Sterculia pilosa, Laetia procera, Dinizia excelsa e Schefflera morototoni. Estudos sobre a taxa de crescimento, em períodos mais longos, são necessários para confirmar a utilização dessas espécies em plantios de enriquecimento de clareiras oriundas de exploração florestal, como alternativa para aumentar a produtividade e o valor econômico das florestas naturais manejadas na Amazônia brasileira.Survival of seedlings planted in 400 gaps created by reduced impact logging in a terra firme forest in the Eastern Amazonia was evaluated. 3,818 seedlings from 17 species occurring in the study area, except for Schizolobium amazonicum (paricá, which is rare in natural forests of Paragominas region, were planted in the gaps. Spacing of planted seedlings was 5m. According to survival of seedlings during 11 months after planting, the species Schizolobium amazonicum, Cedrela odorata, Jacaranda copaia, Manilkara huberi, Astronium gracile, Pouteria bilocularis, Tabebuia impetiginosa,Pseudopiptadenia suaveolens, Cordia goeldiana, Parkia gigantocarpa, Simarouba amara, Sterculia pilosa, Laetia procera, Dinizia excelsa and Schefflera morototoni can be suggested for enriching in gaps created by reduced impact logging

  5. How mosquitoes fly in the rain

    Science.gov (United States)

    Dickerson, Andrew; Shankles, Peter; Madhavan, Nihar; Hu, David

    2011-11-01

    Mosquitoes thrive during rainfall and high humidity. If raindrops are 50 times heavier than mosquitoes, how do mosquitoes fly in the rain? In this combined experimental and theoretical study, we measure the impact force between a falling drop and a free-flying mosquito. High-speed videography of mosquitoes and custom-built mimics reveals a mosquito's low inertia renders it impervious to falling drops. Drops do not splash on mosquitoes, but simply push past them allowing a mosquito to continue on its flight path undeterred. We rationalize the force imparted using scaling relations based on the time of rebound between a falling drop and a free body of significantly less mass.

  6. EFFECTS OF RAIN ATTENUATION ON SATELLITE COMMUNICATION LINK

    Directory of Open Access Journals (Sweden)

    G. N. Ezeh

    2014-06-01

    Full Text Available Rain attenuation is a major challenge to microwave satellite communication especially at frequencies above 10 GHz, causing unavailability of signals most of the time. Rain attenuation predictions have become one of the vital considerations while setting up a satellite communication link. In this study, rain attenuation models, cumulative distribution curves and other analytical tools for successful prediction of rain attenuation are presented. A three year Rain rate data was obtained from the Nigeria Meteorological Agency (NIMET database in addition to experimental data. Of the three prediction models used in the study, Ajayi model gave the range of values closest to the experimental data. A correctional factor was determined as 1.0988 and used to modify the Ajayi model. This modification to Ajayi’s model enabled its rain attenuation values conform more closely to the experimental result.

  7. Research on acid rain/forest die-back. Final report. Turnover of sulfur, nitrogen, and heavy metal between components of the ecosystem and distribution to ecosystem compartments, as well as their direct and indirect effects on organisms. Forschungsbericht Saurer Regen/Waldsterben. Abschlussbericht. Schwefel-, Stickstoff- und Schwermetall-Umsatz zwischen Oekosystemkompartimente und -Verteilung auf Oekosystemkompartimente sowie deren (in-)direkte Auswirkung auf Organismen

    Energy Technology Data Exchange (ETDEWEB)

    Flegr, M.; Koerner, J. (Tuebingen Univ. (Germany, F.R.). Inst. fuer Geologie und Palaeontologie); Monn, L. (Hohenheim Univ., Stuttgart (Germany, F.R.). Inst. fuer Bodenkunde und Standortslehre)

    1989-01-01

    For four typical sites with beech and/or spruce stands, budgets were established in 1985-1986 for their turnovers of H, Na, Mg, K, Ca, Cl, NO{sub 3}, NH{sub 4}, SO{sub 4}, HCO{sub 3} as well as for Fe, Mn, Zn, Cu, Pb, Cd and Ni from atmospheric uptake with both precipitations in the field and on the site (including stemflow water for beech), and from the dicharges from sites or areas including interflow, leachate, well water and brook water. Investigations regarding the effects deal with nitrogen mineralization in the main rhizospheres of the sites and with the distribution of nutrients and pollutants to plants or parts of plants, leaves, needles, and roots of forest trees and to shoots of herbs as well as to the rhizosphere and soil or soil layers also in sites without tree injury or with moderate to severe tree injury in the Black Forest and the lower ranges of the Swabian Jura. (orig./MG).

  8. Seed Dynamics in Relation to Gaps in a Tropical Montane Rainforest of Hainan Island,South China:(Ⅰ) Seed Rain

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Seed dynamics is an important part of stand dynamics in forest ecosystems.In this paper,26 gaps were randomly selected to study the influence of gaps on the spatial and temporal patterns of seed rains in a tropical montane rainforest of Hainan Island,South China.Three zones for each gap,including outside gap zone(Non-gap),transitional gap zone(EG-CG),and central gap zone(CG),were designed,and four seed traps(each 1m × 1m in size)were placed in each zone.Seed rains were collected by these traps every 10 days from June 2001 to May 2002.Seed rain varied greatly with season and generally exhibited a pattern of unimodal change during the study period:seed abundance and species richness were both greater in the wet season than in the dry season.Gaps significantly influenced the temporal patterns of both species richness and density of seed rains.Gaps had no significant influences on the spatial distribution patterns of seed rain species richness,but significantly affected the spatial distribution pattern of seed rain densities.Among the three different zones of gaps,the outside gap zone generally received more seeds inputs than the two other gap zones.

  9. Spatial and temporal characteristics of rain intensity in the peninsular Malaysia using TRMM rai