WorldWideScience

Sample records for autecology

  1. Algal Attributes: An Autecological Classification of Algal Taxa Collected by the National Water-Quality Assessment Program

    Science.gov (United States)

    Porter, Stephen D.

    2008-01-01

    Algae are excellent indicators of water-quality conditions, notably nutrient and organic enrichment, and also are indicators of major ion, dissolved oxygen, and pH concentrations and stream microhabitat conditions. The autecology, or physiological optima and tolerance, of algal species for various water-quality contaminants and conditions is relatively well understood for certain groups of freshwater algae, notably diatoms. However, applications of autecological information for water-quality assessments have been limited because of challenges associated with compiling autecological literature from disparate sources, tracking name changes for a large number of algal species, and creating an autecological data base from which algal-indicator metrics can be calculated. A comprehensive summary of algal autecological attributes for North American streams and rivers does not exist. This report describes a large, digital data file containing 28,182 records for 5,939 algal taxa, generally species or variety, collected by the U.S. Geological Survey?s National Water-Quality Assessment (NAWQA) Program. The data file includes 37 algal attributes classified by over 100 algal-indicator codes or metrics that can be calculated easily with readily available software. Algal attributes include qualitative classifications based on European and North American autecological literature, and semi-quantitative, weighted-average regression approaches for estimating optima using regional and national NAWQA data. Applications of algal metrics in water-quality assessments are discussed and national quartile distributions of metric scores are shown for selected indicator metrics.

  2. A Study on the Autecology of Reseda lutea L. (Resedaceae) Distributed in Western Anatolia

    OpenAIRE

    Doğan, Yunus

    2001-01-01

    The aim of this study was to determine the autecological characteristics of Reseda lutea L. (Resedaceae) distributed in Western Anatolia. The chemical and physical analysis was carried out on soil and plant samples collected from 54 different localities in Western Anatolia. The results show that the plant generally prefers sandy-loam and sandy-clayey-loam textural soils, with a slightly alkaline or medium alkaline pH. They prefer non-saline, calcareous soils which are poor in potassium and ph...

  3. The use of ecological theory and autecological datasets in studies of endangered plant and animal species and communities

    Directory of Open Access Journals (Sweden)

    Hodgson, John G.

    1991-12-01

    Full Text Available Few, if any, European habitats have been unaffected by modern land-use and the problems of conserving the diversity of the European flora and fauna are both urgent and immense. This paper describes a simple method for analyzing floristic change that is hoped will prove useful for assessing the nature and severity of these threats. The method involves the use of ecological theory and the collection of simple autecological data. Examples are given to illustrate how this approach can be used both to identify reasons for floristic change and to provide functional analyses of phytosociological data. Also, as a result of analyses of reasons for commonness and rarity in butterflies and birds, it is argued that similar functional interpretations of zoological datasets may soon be possible.

    [es] Considerando que prácticamente todos los hábitats de Europa han sido afectados por los usos de la tierra modernos, la conservación de la diversidad de su flora y fauna se presenta como un problema muy grave y urgente. En este artículo se describe un método simple para analizar cambios florísticos, contemplando el uso de la teoría ecológica y la colección de datos autoecológicos sencillos. Dicho método constituye una herramienta para evaluar la naturaleza y severidad de procesos de pérdida de la diversidad biológica. Se dan ejemplos ilustrando el uso de este enfoque en la identificación de las causas de cambios florísticos y en el análisis funcional de datos fitosociológicos. Se presentan, además, las razones que explican la presencia de especies raras o muy comunes de mariposas y aves. A partir de estos últimos resultados, se concluye que en breve será posible realizar una interpretación funcional similar de datos zoológicos.
    [de] Nur wenige, wenn überhaupt, der Lebensrame in Europa sind unberührt von moderner Landnutzung und die Probleme der Erhaltung der Vielfalt in der Flora und Fauna sind sowohl dringend als auch immens

  4. Autecology of microorganisms of typical Ecuador biotopes.

    Science.gov (United States)

    Tashyrev, O B; Pidgorskyi, V S; Toro, Miguel Naranjo; Gualoto, Miguel; Gladka, G V; Tashyreva, H O; Rokitko, P V; Romanovskaya, V A

    2014-01-01

    34 strains of aerobic chemoorganotrophic microorganisms were isolated from 23 soil and plant samples selected from highland biotopes of Ecuador-Andes massif (Papallacta, 4020 m), ash at the foot of the volcano Tungurahua, mountainous jungle (La Favorita, 1600 m), as well as in humid tropic botanical garden (state Puyo, 950 m). In mountain jungle samples the high number of bacteria--10(5)-10(7) CFU/g of sample were represented by 2-5 morphotypes. In highland (4020 m) samples the bacterial counts made from 10(2) to 10(7) CFU/g of sample. The current study describes resistance of isolated strains to high salinity, UV radiation and toxic metal ions. The majority of isolated strains were halotolerant. Isolates from volcanic ash showed high resistance level to UV radiation--LD99,99 made 1000-1440 J/m2; resistance level for isolates from the soil of Puyo Botanical Garden and isolates from rock lichen (Papallacta) LD99,99 made 1160 and 800 J/m2 respectively. Strains isolated from mountain jungle (La Favorita) showed lower UV-resistance. In highland biotopes of Ecuador occurred bacteria resistant to toxic metal ions. The highest resistance to Hg2+ was shown by isolate of lichen from mountain jungle, the maximal growth concentration was 0.025 g/L; to Cr(VI)--by isolate from lichen rock massif--3,0 g/L. Correlation between metal-resistance, halotolerace and UV resistance for studied strains was not detected, probably because of different microbial cell damage/repair mechanisms under the action of these factors. PMID:25639037

  5. Autecology of Vibrio vulnificus and Vibrio parahaemolyticus in tropical waters

    Energy Technology Data Exchange (ETDEWEB)

    Rivera, S.; Lugo, T.; Hazen, T.C. [Univ. of Puerto Rico, Rio Piedras (Puerto Rico)

    1988-12-31

    Water and shellfish samples collected from estuaries, mangroves, and beaches along the coast of Puerto Rico were examined for Vibrio vulnificus and Vibrio parahaemolyticus. An array of water quality parameters were also measured simultaneous with bacteria sampling. Both species of vibrio were associated with estuary and mangrove locations, and neither was isolated from sandy beaches. Densities of V. vulnificus were negatively correlated with salinity, 10--15 ppt being optimal. V. parahaemolyticus was isolated from sites with salinities between 20 and 35 ppt, the highest densities occurring at 20 ppt. Densities of Vibrio spp. and V. parahaemolyticus for a tropical estuary surpassed those reported for temperate estuaries by several orders of magnitude. Both densities of total Vibrio spp. and V. parahaemolyticus in the water were directly related to densities of fecal coliforms, unlike V. vulnificus. The incidence of ONPG(+) strains among sucrose({minus}) Vibrio spp. served as an indicator of the frequency of V. vulnificus in this group. More than 63% of the V. vulnificus isolated were pathogenic. V. vulnificus and V. parahaemolyticus occupy clearly separate niches within the tropical estuarine-marine ecosystem.

  6. Energy and carbon balances in cheatgrass, an essay in autecology. [Shortwave radiation, radiowave radiation

    Energy Technology Data Exchange (ETDEWEB)

    Hinds, W.T.

    1975-01-01

    An experiment to determine the fates of energy and carbon in cheatgrass (Bromus tectorum L.) was carried out on steep (40/sup 0/) north- and south-facing slopes on a small earth mound, using many small lysimeters to emulate swards of cheatgrass. Meteorological conditions and energy fluxes that were measured included air and soil temperatures, relative humidity, wind speed, incoming shortwave radiation, net all-wave radiation, heat flux to the soil, and evaporation and transpiration separately. The fate of photosynthetically fixed carbon during spring growth was determined by analysis of the plant tissues into mineral nutrients, crude protein, crude fat, crude fiber, and nitrogen-free extract (NFE) for roots, shoots, and seeds separately. (auth)

  7. Distribution and autecology of chrysophyte cysts from high Arctic Svalbard lakes: preliminary evidence of recent environmental change

    OpenAIRE

    Betts-Piper, Alexandra M.; Zeeb, Barbara A.; John P. Smol

    2004-01-01

    Chrysophycean stomatocyst assemblages were analysed from the sediments of 17 lakes and ponds from Svalbard as one component of a multi-proxy investigation of recent environmental change in the high Arctic. Sediment cores and water chemistry were collected from each of the study lakes, and chrysophyte stomatocysts were investigated from the top 0.25 cm of sediment (present-day) and bottom (i.e. bottom of short sediment core, pre-industrial) sediment samples. This study represents the first und...

  8. Learning from Traditional Knowledge of Non-timber Forest Products: Penan Benalui and the Autecology of Aquilaria in Indonesian Borneo

    OpenAIRE

    Donovan, D. G.; Puri, R. K.

    2004-01-01

    Traditional knowledge, promoted to make conservation and development more relevant and socially acceptable, is shown to have an important role in identifying critical research needs in tropical ecology. Botanists, foresters, and phytochemists, among others, from many countries have sought for decades to understand the process of resin formation in the genus Aquilaria, a tropical forest tree of South and Southeast Asia. Not every tree develops the resin and, despite extensive scientific resear...

  9. Learning from Traditional Knowledge of Non-timber Forest Products: Penan Benalui and the Autecology of Aquilaria in Indonesian Borneo

    Directory of Open Access Journals (Sweden)

    D. G. Donovan

    2004-12-01

    Full Text Available Traditional knowledge, promoted to make conservation and development more relevant and socially acceptable, is shown to have an important role in identifying critical research needs in tropical ecology. Botanists, foresters, and phytochemists, among others, from many countries have sought for decades to understand the process of resin formation in the genus Aquilaria, a tropical forest tree of South and Southeast Asia. Not every tree develops the resin and, despite extensive scientific research, this process remains poorly understood. Attempts at cultivating the valuable aromatic resin, gaharu, have been uneven at best. Thus, gaharu remains largely a natural forest product, increasingly under threat as the trees are overexploited and forest is cleared. In this paper, we compare scientific knowledge and traditional knowledge of the Penan Benalui and other forest product collectors of Indonesian Borneo. Although limited management of wildlings failed to bring the resin-producing species under cultivation, we found that the Penan recognize the complex ecology of resin formation involving two, or maybe three, living organisms—the tree, one or more fungi, and possibly an insect intermediary. Developing a sustainable production system for this resource will require a clear understanding of how these various natural elements function, separately and synergistically. Traditional knowledge can help fill gaps in our information base and identify promising areas for future research. Both correspondence and gaps in knowledge support the call for a greater role for ethnobiological research and interdisciplinary cooperation, especially between ethnobiologists and foresters, in developing sustainable management systems for this traditional resource and its natural habitat.

  10. Autecology and conservation status of Magnolia sargentiana Rehder & Wilson (Magnoliaceae) in the Dafengding region, southern Sichuan Province, China

    Institute of Scientific and Technical Information of China (English)

    Jing WANG; Ya TANG; Zheng-Hua XIE; Mian-Yue ZHANG

    2009-01-01

    This paper reports the first population ecology study of the endangered Magnolia sargentiana Rehder & Wilson (Magnoliaceae). Magnolia sargentiana is a protected species in China, but little is known about its present status in the field. In 2007 and 2008, we surveyed the population and conservation status of M. sargentiana in the Provincial Mamize Nature Reserve and the National Meigu Dafengding Nature Reserve, Sichuan Province, southwestern China. Natural regeneration is poor because of unfavorable environmental conditions and anthropogenic disturbances. Flower buds and bark of M. sargentiana are used in traditional Chinese medicine and their collection by local people over the period 1983-1994 has led to marked population declines. The collection of flower buds and bark is now banned, but hewing branches for firewood and grazing continues to have a negative impact on the recovery of M. sargentiana populations. To protect the species, we require a ban on hewing branches, closure of primary forests to reduce the impact of humans and ungulates, better education of local people, and increased awareness of wildlife conservation.

  11. Superficial ecosystem similarities vs autecological stripping: the "twin species" Mesocyclops leuckarti (Claus and Thermocyclops oithonoides (Sars - seasonal habitat utilisation and life history traits

    Directory of Open Access Journals (Sweden)

    Svein Birger WÆRVÅGEN

    2000-08-01

    Full Text Available Mesocyclops leuckarti and Thermocyclops oithonoides, among the most common European species of cyclopoid copepods, immigrated to central Europe from eastern refuges after the last glaciation. M. leuckarti arrived prior to T. oithonoides. In a border region of T. oithonoides in southern Norway, the species was found exclusively below the highest postglacial marine limit, whereas it had spread to other neighbouring lakes above the former marine limit close to its more central region of distribution in eastern Norway. The habitat of M. leuckarti is characteristically both littoral/profundal and planktonic, whereas T. oithonoides is a true planktonic species. The egg sacs of the larger species M. leuckarti protrude from its genital segment, likely increasing water friction. M. leuckarti has probably developed strategies to reduce predation on eggbearing females, such as staying in littoral, profundal or oxygen boundary regions where fish are either absent or experience hunting difficulties. We hypothesise that the numerical suppression of M. leuckarti, its sex ratio, the habitat distribution of adult females, and its life cycles in many eutrophic lakes, is strongly affected by fish predation. M. leuckarti is considerably larger than T. oithonoides; total body length: 1.0-1.3 mm vs 0.7-1.0, respectively. The negligibly coloured and smaller adult T. oithonoides may be outside the prey range for many fish species. In the lowland region, both species completed several numbers of reproductive cycles annually. There were various patterns of diannual and triannual life cycles. Some populations exhibited a conspicuously delayed revival from sediment diapause, others in eutrophic lakes developed slowly during the summer (probably due to naupliar competition from cladocerans, or stayed in the plankton during prolonged periods during autumn. At higher altitudes and in large cold lakes, one generation a year was recorded. In its northern range, M. leuckarti showed sediment diapause in all types of localities, even the deepest lakes, usually in the upper littoral region. In more shallow lakes, deeper diapause sites were observed. T. oithonoides diapaused in either the lower littoral, or the profundal regions. M. leuckarti showed different life cycles in localities within the same geographical region, especially in its southern range. In the shallow part of Bodensee in Germany it entered sediment diapause, whereas in the much deeper main basin it showed plankton diapause (also called "active diapause". The period of diapause for M. leuckarti (especially in the sediment decreased from north to south. At about 45º N, sediment and plankton diapause were non-existent, and the species exhibited continuous development, even with relatively low winter temperatures (in Lago Maggiore. T. oithonoides, whose southern distribution in western Europe extends to about 50º N, showed winter sediment diapause throughout its distribution, but frequently with a fraction of the local population in plankton diapause. The combined effects of these different abiotic and biotic parameters help explain the variations of life histories observed in the field.

  12. Flora e aspectos auto-ecológicos de um encrave de cerrado na chapada do Araripe, Nordeste do Brasil Flora and autecology's aspects of a disjunction cerrado at Araripe plateau, Northeastern Brazil

    Directory of Open Access Journals (Sweden)

    Itayguara Ribeiro da Costa

    2004-12-01

    Full Text Available Este trabalho visa conhecer a composição e riqueza florística, os padrões fenológicos reprodutivos, as síndromes de dispersão e as formas de vida das espécies de uma disjunção de cerrado em clima semi-árido, na chapada do Araripe, Estado do Ceará. Foram encontradas 107 espécies e 41 famílias. Fabaceae, Myrtaceae, Poaceae, Apocynaceae, Euphorbiaceae e Malpighiaceae foram as mais ricas em espécies. Foi feita a distribuição geográfica de 47 espécies arbustivas e arbóreas em 27 listagens de cerrados brasileiros. Doze espécies apresentaram ampla distribuição geográfica e 13 foram registradas apenas neste trabalho. Cerca de 76% das espécies floresceram e frutificaram no período chuvoso. As síndromes de dispersão predominantes foram: zoocoria, autocoria e anemocoria. O espectro biológico foi predominantemente constituído por fanerófitos (50,7%, hemicriptófitos (14,9% e caméfitos (13,1%. O cerrado estudado apresentou menor riqueza taxonômica que os cerrados contínuos e comportamento das fenofases reprodutivas, percentagem de síndromes de dispersão e formas de vida similares.This study subject to investigate the floristic composition and richness, the reproductive phenological patterns, the dispersal syndromes and life forms of species of a disjunt cerrado in semiarid climate at Araripe plateau during a one year period. We found 107 species and 41 families. Fabaceae, Myrtaceae, Poaceae, Apocynaceae, Euphorbiaceae and Malpighiaceae showed the largest number of species. For 47 of the woody species found, we studied the geographical distribution based on 27 papers of the Brazilian cerrados. Twelve species are of widespread occurence in the cerrado, and 13 are restricted to the Araripe plateau. Zoocory, autocory, and anemocory are the predominant syndromes of dispersal. The predominant life forms were phanerophytes (50.7%, hemicriptophytes (14.9% and camephytes (13.1%. The cerrado of Araripe have lower species richness than continous cerrados, but a similar pattern of reproductive phenology, dispersal syndromes and life forms in more humid zones.

  13. Autecology Essential Oil Composition, Antibacterial, Anti Candidacies and Ethnopharmacological Survey of Ferula Gummosa L. As Anti Infection to Treat Of Vaginal Infections in Traditional Medicine of Razavi Khorasan Province (North East of Iran

    Directory of Open Access Journals (Sweden)

    Mazandarani Masoumeh

    2015-04-01

    Full Text Available Objective: Ferula gummosa Boiss. (Apiaceae family, which has been used in traditional medicine of Iran as anti vaginal infection, anti-sinusitis, sedative, and anti-inflammation. Materials and Methods: In this research, the gums of plant root were collected from the Heidary nature reserve in Razavi Khorasan Province (Iran in August 2012. The ethnopharmacological data about traditional uses of plant were obtained from the rural healers (women 67-75 year of this region. Essential oil of the plant root gum was obtained by hydrodistillation (Clevenger apparatus and was analyzed by gas chromatography–mass spectrometry. Antibacterial activity of plant ethanolic extract was studied in vitro against Candida albicans and 9 Gram-positive and negative bacteria using well method and the minimum inhibitory concentration (MIC assay. Results: Results showed that a total of 39 components have been identified in the plant sampl oil, representing 81% of the total oil and β-pinene (19.88%, guaiol (8%, shyobunone (6.96%, delta-cadinene (4.65%, α-pinene (3.16 %, β-phellandrene (3.28% and myrtenol (2.8%, were the main essential oil composition, respectively. The results from antibacterial screening (Table 2, were showed that C. albicans (25.2 ± 1.6, Staphylococcus epidermidis (23.6 ± 0.7 mm, Staphylococcus aureus (21.3 ± 0.2 mm, Escherichia coli (16.5 ± 0.8 mm, Bacillus cereus (19.5 ± 0.1 mm, Enterococcus faecalis (17.2 ± 0.8 mm and Pseudomonas aeroginosa ( 17.8 ± 0.2 mm inhibition zone and MIC (35.4-112 μg/ml were the most sensitive pathogenes to the plant extract respectively, which followed Shigella (12.3 ± 0.3 mm and Klebsiella pneumonia (12.5 ± 0.2 mm were found to be moderate sensitive bacteria and then the Salmonella typhymorium which completely was resistant to plant root extract. Conclusion: According to these results, it can be concluded that the extract of F. gummosa L. have suitable antimicrobial and anti-Candidacies activity, which can be used as natural anti-infection to treat of many infection diseases, especially in vaginal infection.

  14. Records of the Giant Otter, Pteronura brasiliensis, from Guyana

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    Barnett A.

    2000-10-01

    Full Text Available The results of interviews and surveys of status of the giant otter are presented. These include information on Pteronura brasiliensis on the upper Potaro River and other rivers in Guyana. Suggestions are made for future work on giant otters on the Potaro Plateau. These include monitoring the effects of mining, studies of mercury poisoning, ecotourism feasibility studies and autecological studies.

  15. Genomics and Ecophysiology of Heterotrophic Nitrogen-Fixing Bacteria Isolated from Estuarine Surface Water

    OpenAIRE

    Bentzon-Tilia, Mikkel; Severin, Ina; Hansen, Lars H.; Riemann, Lasse

    2015-01-01

    The ability to reduce atmospheric nitrogen (N2) to ammonia, known as N2 fixation, is a widely distributed trait among prokaryotes that accounts for an essential input of new N to a multitude of environments. Nitrogenase reductase gene (nifH) composition suggests that putative N2-fixing heterotrophic organisms are widespread in marine bacterioplankton, but their autecology and ecological significance are unknown. Here, we report genomic and ecophysiology data in relation to N2 fixation by thre...

  16. Effect of ciliates on nitrification and nitrifying bacteria in Baltic Sea sediments

    OpenAIRE

    Prast, M.; Bischof, Adrian A.; Waller, Uwe; Amann, R.; Berninger, U.-G.

    2007-01-01

    Nitrification in aquatic sediments is catalyzed by bacteria. While many autecological studies on these bacteria have been published, few have regarded them as part of the benthic microbial food web. Ciliates are important as grazers on bacteria, but also for remineralization of organic matter. We tested the hypothesis that ciliates can affect nitrification. Experiments with Baltic Sea sediments in laboratory flumes, with or without the addition of cultured ciliates, were conducted. We found i...

  17. Sea surface conditions in the southern Nordic Seas during the Holocene based on dinoflagellate cyst assemblages

    DEFF Research Database (Denmark)

    Van Nieuwenhove, Nicolas; Baumann, Astrid; Matthiessen, Jens;

    2016-01-01

    in many areas of the Nordic Seas and appears to have an important effect on cyst concentrations and assemblage composition, with the possible loss of oxygenation-sensitive cysts in the older parts of the cores. Comparing dinocyst-based quantitative reconstructions with those retrieved from other plankton...... reveals a significantly different trend between proxies, linked to a differing autecological response to seasonal changes at their respective depth habitats....

  18. Diatom Assessment of Wetland Condition at Genus, Species, and Subspecies Taxonomic Resolution

    Science.gov (United States)

    Lane, C. R.

    2005-05-01

    This study was conducted to determine if epiphyton-based metrics could be developed using mean autecological values at genus, species, and subspecies taxonomic levels. Epiphytic diatoms from 69 isolated depressional marshes in peninsular Florida were sampled once in either the summers of 1999 or 2000. Soil and water parameters were also sampled. Thirty genera, 148 species, and 26 subspecies were identified. The proportional matrices at each taxonomic level were highly similar. Autecological metrics, based on weighted averages, were developed for pH class, salinity tolerance, N uptake metabolism, oxygen requirements, saprobity level, trophic status, moisture requirement, and pollution tolerance at each taxonomic level. Two additional metrics based on indicator species analysis were also developed. Wetland condition, as determined by summed metric values, was strongly correlated across taxonomic level, and no difference was found when sites were placed into categorical bins based on quartile scoring for each taxonomic level. Specific conductance, soil pH, soil and water total phosphorous, and total Kjeldahl nitrogen were significantly related to site ordination scores at each taxonomic level. This study concludes that indices of biotic integrity, when developed using autecological indices, provide similar qualitative conditional information across taxonomic levels.

  19. Pollination mechanisms in palms – a synoecological perspective

    DEFF Research Database (Denmark)

    Barfod, Anders S.; Hagen, Melanie; Borchsenius, Finn

    More than 60 pollination ecological studies have been conducted on palms since Henderson’s almost 25 year old review of palm pollination. Most studies are aut-ecological studies that provide a detailed snapshot of the pollination of a limited number of palm individuals of the same species. They...... confirm that most palm inflorescences offer a loose framework for the interaction between the palms and their insect visitors. The pollinators are typically weevils (superfamily Curculionidea), rove beetles (family Staphylinidae), sweat bees (family Halictidae), stingless bees (tribe Meliponini, family...... Apidae), and flies (order Diptera). Less is known about variations in the composition of the visiting insect fauna across the geographic range of a given palm species. A number canopy studies have contributed to our understanding of palms in broader palm-pollinator networks and provided insight on the...

  20. Relationships between diatoms and tidal environments in Oregon and Washington, USA

    Science.gov (United States)

    Sawai, Yuki; Horton, Benjamin P.; Kemp, Andrew C.; Hawkes, Andrea D.; Nagumo, Tamostsu; Nelson, Alan R.

    2016-01-01

    A new regional dataset comprising 425 intertidal diatom taxa from 175 samples from 11 ecologically diverse Oregon and Washington estuaries illustrates the importance of compiling a large modern dataset from a range of sites. Cluster analyses and detrended correspondence analysis of the diatom assemblages identify distinct vertical zones within supratidal, intertidal and subtidal environments at six of the 11 study sites, but the abundance of some of the most common species varies widely among and within sites. Canonical correspondence analysis of the regional dataset shows relationships between diatom species and tidal exposure, salinity and substratum (grain size and organic content). Correspondence analyses of local datasets show higher values of explained variation than the analysis of the combined regional dataset. Our results emphasize that studies of the autecology of diatom species require many samples from a range of modern environments to adequately characterize species–environment relationships.

  1. Comparison of the autoecology of Quercus robur L. and Q. petraea (Mattuschka Liebl. stands in the Northwest of the Iberian Peninsula

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    A. Rodriguez-Campos

    2010-09-01

    Full Text Available The purpose of the present work is to characterize the functioning of the ecosystems of semideciduous and deciduous Atlantic oaks in the northwest of the Iberian Peninsula. The studied species were: Quercus robur L. and Quercus petraea (Mattuschka Liebl. To advance in the knowledge of the autecology of these species it is necessary to descend at the regional level and describe in detail the variability of the environment to determine their potential, and to decide the silvicultural treatments to be applied to preserve them and to analyze future actuations in order to a possible expansion. The analysis of the results allows knowing differences in continentalityand site conditions, with more precipitation, soil variability and humidification in Q. petraea forests respect to Q. robur. These information represent appropriate measures for the sustainable and multifunctional management of these forests, useful as indicators environmental and forestry parameters as well as the conservationstatus of these formations.

  2. The woody vegetation communities of the Hluhluwe-Corridor- Umfolozi Game Reserve Complex

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    A. Whateley

    1983-12-01

    Full Text Available Land units for the 900 km- Hluhluwe-Corridor-Umfolozi Game Reserve Complex in north eastern Natal were identified on aerial photographs. The physiognomy, dominants and description of the woody vegetation for each unit were identified during ground inspections and. where necessary, the point-centred quarter method was applied. Two forest, two riverine forest, ten woodland and two thicket communities were recognized. These communities are described according to their distribution, height and percentage frequency of the components in the different canopy strata. A map at a scale of 1:25 000 was also compiled. Some of these communities are compared with other similar woodlands previously described for Natal. In some communities the frequency of certain dominant canopy species in the under tree strata was extremely low and autecological research has been suggested.

  3. Developing priority variables ("ecosystem Essential Ocean Variables" - eEOVs) for observing dynamics and change in Southern Ocean ecosystems

    Science.gov (United States)

    Constable, Andrew J.; Costa, Daniel P.; Schofield, Oscar; Newman, Louise; Urban, Edward R.; Fulton, Elizabeth A.; Melbourne-Thomas, Jessica; Ballerini, Tosca; Boyd, Philip W.; Brandt, Angelika; de la Mare, Willaim K.; Edwards, Martin; Eléaume, Marc; Emmerson, Louise; Fennel, Katja; Fielding, Sophie; Griffiths, Huw; Gutt, Julian; Hindell, Mark A.; Hofmann, Eileen E.; Jennings, Simon; La, Hyoung Sul; McCurdy, Andrea; Mitchell, B. Greg; Moltmann, Tim; Muelbert, Monica; Murphy, Eugene; Press, Anthony J.; Raymond, Ben; Reid, Keith; Reiss, Christian; Rice, Jake; Salter, Ian; Smith, David C.; Song, Sun; Southwell, Colin; Swadling, Kerrie M.; Van de Putte, Anton; Willis, Zdenka

    2016-09-01

    Reliable statements about variability and change in marine ecosystems and their underlying causes are needed to report on their status and to guide management. Here we use the Framework on Ocean Observing (FOO) to begin developing ecosystem Essential Ocean Variables (eEOVs) for the Southern Ocean Observing System (SOOS). An eEOV is a defined biological or ecological quantity, which is derived from field observations, and which contributes significantly to assessments of Southern Ocean ecosystems. Here, assessments are concerned with estimating status and trends in ecosystem properties, attribution of trends to causes, and predicting future trajectories. eEOVs should be feasible to collect at appropriate spatial and temporal scales and are useful to the extent that they contribute to direct estimation of trends and/or attribution, and/or development of ecological (statistical or simulation) models to support assessments. In this paper we outline the rationale, including establishing a set of criteria, for selecting eEOVs for the SOOS and develop a list of candidate eEOVs for further evaluation. Other than habitat variables, nine types of eEOVs for Southern Ocean taxa are identified within three classes: state (magnitude, genetic/species, size spectrum), predator-prey (diet, foraging range), and autecology (phenology, reproductive rate, individual growth rate, detritus). Most candidates for the suite of Southern Ocean taxa relate to state or diet. Candidate autecological eEOVs have not been developed other than for marine mammals and birds. We consider some of the spatial and temporal issues that will influence the adoption and use of eEOVs in an observing system in the Southern Ocean, noting that existing operations and platforms potentially provide coverage of the four main sectors of the region - the East and West Pacific, Atlantic and Indian. Lastly, we discuss the importance of simulation modelling in helping with the design of the observing system in the long

  4. Correlations between benthic habitats and demersal fish assemblages — A case study on the Dogger Bank (North Sea)

    Science.gov (United States)

    Sell, Anne F.; Kröncke, Ingrid

    2013-07-01

    The interdependence between groundfish assemblages and habitat properties was investigated on the Dogger Bank in the North Sea. Abiotic habitat parameters considered included topography, hydrographic conditions, sediment composition, and the biotic habitat variable the prevailing benthic invertebrates. Distinct epi- and infauna communities occurred at different locations on the Dogger Bank. Fish assemblages were clearly linked to both the biotic and abiotic habitat characteristics. Overall, fish and benthic communities revealed similar spatial distribution, represented in the respective clusters of characteristic and abundant species. Distribution patterns corresponded with the prevailing abiotic conditions such as depth and sediment composition, which appear to relate to autecological preferences of individual species. The apparently most generalist species, grey gurnard (Eutrigla gurnardus) and dab (Limanda limanda) occurred at all stations and dominated in terms of biomass in most cases. The absolute numbers of grey gurnards were related to the abundance of suitable prey, invertebrate and fish species, which stomach analyses revealed as part of the diet in an independent study during the same research cruise. Haddock (Melanogrammus aeglefinus) and whiting (Merlangius merlangus) were only abundant at deep stations along the flanks of the bank. The occurrence of lemon sole (Microstomus kitt), American plaice (Hippoglossoides platessoides) and cod (Gadus morhua) was also positively correlated with depth, whereas especially lesser weever (Echiichthys vipera), sandeel species and solenette (Buglossidium luteum) occurred predominantly at the shallower sites. At the same time, individual fish species such as solenette and lesser weever were associated with high densities of selected epi- or infauna species.

  5. Progress Towards an Interdisciplinary Science of Plant Phenology: Building Predictions Across Space, Time and Species Diversity

    Science.gov (United States)

    Wolkovich, Elizabeth M.; Cook, Benjamin I.; Davies, T. Jonathan

    2013-01-01

    Climate change has brought renewed interest in the study of plant phenology - the timing of life history events. Data on shifting phenologies with warming have accumulated rapidly, yet research has been comparatively slow to explain the diversity of phenological responses observed across latitudes, growing seasons and species. Here, we outline recent efforts to synthesize perspectives on plant phenology across the fields of ecology, climate science and evolution. We highlight three major axes that vary among these disciplines: relative focus on abiotic versus biotic drivers of phenology, on plastic versus genetic drivers of intraspecific variation, and on cross-species versus autecological approaches. Recent interdisciplinary efforts, building on data covering diverse species and climate space, have found a greater role of temperature in controlling phenology at higher latitudes and for early-flowering species in temperate systems. These efforts have also made progress in understanding the tremendous diversity of responses across species by incorporating evolutionary relatedness, and linking phenological flexibility to invasions and plant performance. Future research with a focus on data collection in areas outside the temperate mid-latitudes and across species' ranges, alongside better integration of how risk and investment shape plant phenology, offers promise for further progress.

  6. Carving out turf in a biodiversity hotspot: multiple, previously unrecognized shrew species co-occur on Java Island, Indonesia.

    Science.gov (United States)

    Esselstyn, Jacob A; Maharadatunkamsi; Achmadi, Anang S; Siler, Cameron D; Evans, Ben J

    2013-10-01

    In theory, competition among species in a shared habitat results in niche separation. In the case of small recondite mammals such as shrews, little is known about their autecologies, leaving open questions regarding the degree to which closely related species co-occur and how or whether ecological niches are partitioned. The extent to which species are able to coexist may depend on the degree to which they exploit different features of their habitat, which may in turn influence our ability to recognize them as species. We explored these issues in a biodiversity hotspot, by surveying shrew (genus Crocidura) diversity on the Indonesian island of Java. We sequenced portions of nine unlinked genes in 100-117 specimens of Javan shrews and incorporated homologous data from most known Crocidura species from other parts of island South-East Asia. Current taxonomy recognizes four Crocidura species on Java, including two endemics. However, our phylogenetic, population genetic and species delimitation analyses identify five species on the island, and all are endemic to Java. While the individual ranges of these species may not overlap in their entirety, we found up to four species living syntopically and all five species co-occurring on one mountain. Differences in species' body size, use of above ground-level habitats by one species and habitat partitioning along ecological gradients may have facilitated species diversification and coexistence.

  7. The integration of climate change, spatial dynamics, and habitat fragmentation: A conceptual overview.

    Science.gov (United States)

    Holyoak, Marcel; Heath, Sacha K

    2016-01-01

    A growing number of studies have looked at how climate change alters the effects of habitat fragmentation and degradation on both single and multiple species; some raise concern that biodiversity loss and its effects will be exacerbated. The published literature on spatial dynamics (such as dispersal and metapopulation dynamics), habitat fragmentation and climate change requires synthesis and a conceptual framework to simplify thinking. We propose a framework that integrates how climate change affects spatial population dynamics and the effects of habitat fragmentation in terms of: (i) habitat quality, quantity and distribution; (ii) habitat connectivity; and (iii) the dynamics of habitat itself. We use the framework to categorize existing autecological studies and investigate how each is affected by anthropogenic climate change. It is clear that a changing climate produces changes in the geographic distribution of climatic conditions, and the amount and quality of habitat. The most thorough published studies show how such changes impact metapopulation persistence, source-sink dynamics, changes in species' geographic range and community composition. Climate-related changes in movement behavior and quantity, quality and distribution of habitat have also produced empirical changes in habitat connectivity for some species. An underexplored area is how habitat dynamics that are driven by climatic processes will affect species that live in dynamic habitats. We end our discussion by suggesting ways to improve current attempts to integrate climate change, spatial population dynamics and habitat fragmentation effects, and suggest distinct areas of study that might provide opportunities for more fully integrative work.

  8. Fauna and paleoecological setting of the La Meseta Formation (Eocene), Antarctica

    Energy Technology Data Exchange (ETDEWEB)

    Feldmann, R.M.; Wiedman, L.A.; Zinsmeister, W.J.

    1985-01-01

    The La Meseta Formation, an Eocene sandstone from Seymour Island, Palmer Peninsula, Antarctica, has yielded a diverse fossil assemblage of body and trace fossils representative of a cool temperate, littoral to shallow sublittoral habitat. Over 61 taxa of macroinvertebrates, excluding gastropod body fossils, and more than 18 ichnogenera collected from the La Meseta represent the largest, most comprehensive and most diverse assemblage of Paleogene fossils from Antarctica. Included in the body fossil assemblage are species representative of at least 26 taxa of bivales, four taxa of echinoids, two of crinoids, two of ophiuroids, two of asteroids, one inarticulate and four articulate brachiopods, two barnacles, six decapod crustaceans, two cyclostome and two cheilostome bryozoans, a scaphopod and one coral. The traces include several burrow forms characteristic of the Skolithos ichnofacies of Seilacher (1967), several halo and rind burrows, gastropod predation borings, and abundant examples of teredid bivalve borings in lithified wood.Autecological analyses of the preserved organisms and environmental interpretations of the ichnogenera indicate a littoral to very shallow sublittoral environment of deposition, generally above wave base, for the la Meseta Sandstone. Modern congeneric descendants of the body fossils are known to inhabit both deep water and shallow water habitats. Of the 20 extant genera of bivalves reported from the La Meseta, 19 generally occur only in cool temperate habitats. Only one genus is known to occur south of 60/sup 0/. Most of the shallow water forms are known from cool temperate, austral regimes.

  9. Faecal-Centric Approaches to Wildlife Ecology and Conservation; Methods, Data and Ethics

    Directory of Open Access Journals (Sweden)

    P. Paquet

    2008-06-01

    Full Text Available Abundant and commonly encountered in the field, wildlife faeces have long attracted scientists. Recent advances in molecular techniques, however, especially when coupled with creative study designs, can now yield a great variety of high quality data. Herein, we review the opportunities and challenges of faecal-centric approaches to address ecological and conservation questions using wolves of coastal British Columbia, Canada, as a case system. We begin by discussing methodological considerations, which should have broad applicability to any wildlife study system. We then summarize the extensive and unique variety of data that has emerged from our ‘facts from faeces’ approach with wolves, which has ranged from descriptive autecology to process-oriented hypothesis-testing to applied conservation management. We conclude by contrasting this non-invasive approach with radio-collaring in an ethics framework. We contend that when the two methods are equally efficacious in answering required research questions, scatology become the only ethical option, a perspective increasingly codified as policy governing research activities.

  10. Differential parasitism of seed-feeding Cydia (Lepidoptera: Tortricidae) by native and alien wasp species relative to elevation in subalpine Sophora (Fabaceae) forests on Mauna Kea, Hawaii

    Science.gov (United States)

    Oboyski, P.T.; Slotterback, J.W.; Banko, P.C.

    2004-01-01

    Alien parasitic wasps, including accidental introductions and purposefully released biological control agents, have been implicated in the decline of native Hawaiian Lepidoptera. Understanding the potential impacts of alien wasps requires knowledge of ecological parameters that influence parasitism rates for species in their new environment. Sophora seed-feeding Cydia spp. (Lepidoptera: Tortricidae) were surveyed for larval parasitoids to determine how native and alien wasps are partitioned over an elevation gradient (2200-2800 m) on Hawaii Island, Hawaii. Parasitism rate of native Euderus metallicus (Eulophidae) increased with increased elevation, while parasitism rate by immigrant Calliephialtes grapholithae (Ichneumonidae) decreased. Parasitism by Pristomerus hawaiiensis (Ichneumonidae), origins uncertain, also decreased with increased elevation. Two other species, Diadegma blackburni (Ichneumonidae), origins uncertain, and Brasema cushmani (Eupelmidae), a purposefully introduced biological control agent for pepper weevil, did not vary significantly with elevation. Results are contrasted with a previous study of this system with implications for the conservation of an endangered bird species that feed on Cydia larvae. Interpretation of results is hindered by lack of knowledge of autecology of moths and wasps, origins, phylogeny, systematics, competitive ability, and physiological limitations of each wasp species. These factors should be incorporated into risk analysis for biological control introductions and invasive species programs. ?? 2004 Kluwer Academic Publishers.

  11. Does beach nourishment have long-term effects on intertidal macroinvertebrate species abundance?

    Science.gov (United States)

    Leewis, Lies; van Bodegom, Peter M.; Rozema, Jelte; Janssen, Gerard M.

    2012-11-01

    Coastal squeeze is the largest threat for sandy coastal areas. To mitigate seaward threats, erosion and sea level rise, sand nourishment is commonly applied. However, its long-term consequences for macroinvertebrate fauna, critical to most ecosystem services of sandy coasts, are still unknown. Seventeen sandy beaches - nourished and controls - were sampled along a chronosequence to investigate the abundance of four dominant macrofauna species and their relations with nourishment year and relevant coastal environmental variables. Dean's parameter and latitude significantly explained the abundance of the spionid polychaete Scolelepis squamata, Beach Index (BI), sand skewness, beach slope and latitude explained the abundance of the amphipod Haustorius arenarius and Relative Tide Range (RTR), recreation and sand sorting explained the abundance of Bathyporeia sarsi. For Eurydice pulchra, no environmental variable explained its abundance. For H. arenarius, E. pulchra and B. sarsi, there was no relation with nourishment year, indicating that recovery took place within a year after nourishment. Scolelepis squamata initially profited from the nourishment with "over-recolonisation". This confirms its role as an opportunistic species, thereby altering the initial community structure on a beach after nourishment. We conclude that the responses of the four dominant invertebrates studied in the years following beach nourishment are species specific. This shows the importance of knowing the autecology of the sandy beach macroinvertebrate fauna in order to be able to mitigate the effects of beach nourishment and other environmental impacts.

  12. The integration of climate change, spatial dynamics, and habitat fragmentation: A conceptual overview.

    Science.gov (United States)

    Holyoak, Marcel; Heath, Sacha K

    2016-01-01

    A growing number of studies have looked at how climate change alters the effects of habitat fragmentation and degradation on both single and multiple species; some raise concern that biodiversity loss and its effects will be exacerbated. The published literature on spatial dynamics (such as dispersal and metapopulation dynamics), habitat fragmentation and climate change requires synthesis and a conceptual framework to simplify thinking. We propose a framework that integrates how climate change affects spatial population dynamics and the effects of habitat fragmentation in terms of: (i) habitat quality, quantity and distribution; (ii) habitat connectivity; and (iii) the dynamics of habitat itself. We use the framework to categorize existing autecological studies and investigate how each is affected by anthropogenic climate change. It is clear that a changing climate produces changes in the geographic distribution of climatic conditions, and the amount and quality of habitat. The most thorough published studies show how such changes impact metapopulation persistence, source-sink dynamics, changes in species' geographic range and community composition. Climate-related changes in movement behavior and quantity, quality and distribution of habitat have also produced empirical changes in habitat connectivity for some species. An underexplored area is how habitat dynamics that are driven by climatic processes will affect species that live in dynamic habitats. We end our discussion by suggesting ways to improve current attempts to integrate climate change, spatial population dynamics and habitat fragmentation effects, and suggest distinct areas of study that might provide opportunities for more fully integrative work. PMID:26458303

  13. Stomach emptiness in fishes: Sources of variation and study design implications

    Science.gov (United States)

    Vinson, M.R.; Angradi, T.R.

    2011-01-01

    This study summarizes fish stomach content data from 369,000 fish from 402 species in 1,096 collections and reports on the percentage of individuals with empty stomachs. The mean percentage of individuals with empty stomachs among all species, locations, habitats, seasons, regions, and collection methods was 26.4%. Mean percentage of individuals with empty stomachs varied significantly among fish collection gear types, taxonomic orders, trophic groups, feeding behaviors, and habitats, and with species length at maturity. Most of the variation in percentage of individuals with empty stomachs was explained by species length at maturity, fish collection gear type, and two autecological factors: trophic group (piscivore percentage of individuals with empty stomachs > non-piscivore percentage of individuals with empty stomachs) and feeding habitat (water column feeder percentage of individuals with empty stomachs > benthic feeder percentage of individuals with empty stomachs). After accounting for variation with fish length, the percentage of individuals with empty stomachs did not vary with the stomach removal collection method (dissection vs. gastric lavage), feeding time (diurnal or nocturnal), or time of collection (day or night). The percentage of individuals with empty stomachs was similar between fresh and saltwater fish, but differed within finer habitat classifications and appeared to follow a general prey availability or productivity gradient: percentage of individuals with empty stomachs of open ocean collections > estuary collections, lentic > lotic, and pelagic > littoral. Gear type (active or passive) was the most influential factor affecting the occurrence of empty stomachs that can be readily controlled by researchers.

  14. Ecological plasticity of Trichoderma fungi in leached chernozem

    Science.gov (United States)

    Svistova, I. D.; Senchakova, T. Yu.

    2010-03-01

    The autecological properties of Trichoderma fungi ecotypes isolated from the leached chernozem of the forest-steppe zone of the European part of Russia have been studied. We were the first who carried out the complex study of the synecological relations of micromycetes of such kinds in a system including the soil, microbial community, and plants, i.e., their relations with soil saprotrophic fungi, bacteria, actinomycetes, plants, and pathogenic fungi. It was shown that the ecological plasticity of the Trichoderma genus in the soil of this zone is determined by its growth rate, the optimum pH and temperature, the biosynthesis of extracellular hydrolytic enzymes, the biological action of mycotoxins, and the ability for parasitism. The efficiency of the introduction of Trichoderma species typical and atypical for the leached chernozem into this soil and their influence on the structure of the microbial community were evaluated. The T. pseudokoningii ecotype, which produces cellulolytic enzymes, is very promising for industrial biotechnology, and the T. harzianum ecotype can be used in soil biotechnology for the biocontrol of chernozem. The addition of a commercial trichodermin preparation into the chernozem damages the structure of its microbial community.

  15. 东江下游惠州河段鱼类群落组成变化特征%Fish Community Changes in Huizhou Segment of Dongjiang River

    Institute of Scientific and Technical Information of China (English)

    刘毅; 林小涛; 孙军; 张鹏飞; 陈国柱

    2011-01-01

    2007~2010年先后5次对东江下游惠州(剑潭)河段鱼类群落进行调查,共采集到鱼类69种,分属于8目20科58属,主要以鲤科(39种)、鲿科(7种)、鳅科(5种)为主.鲮(Cirrhina molitorella)、鲨(Hemiculter leucisculus)、鲤(Cyprinus carpio)、赤眼鳟(Squaliobarbus curriculus)为该河段优势种.除食蚊鱼(Gambusia affinis)外,在该河段新采到4种外来鱼类,分别为罗非鱼(Tilapia sp.)、露斯塔野鲮(Labeo rohita)、麦瑞加拉鲮(Cirrhina mrigala)和下口鲇(Hypostomus plecostomus).与20世纪80年代调查资料相比,目前东江下游惠州河段定居性、杂食性鱼类比例升高,洄游性、肉食性鱼类比例下降.通过个体生态学矩阵(autecology matrix)分析,东江下游河段鱼类群落中肉食性、喜砂砾底质的底层急流鱼类受环境变化影响程度较大.从Simpson指数、Shannon-Wiener指数、Pielou's均匀性指数、Margalef丰富度指数及G-F指数看,剑潭坝上下游河段鱼类群落多样性已开始显现出差异性.大坝建设、水体污染、过度捕捞等是影响东江下游河段鱼类群落变动的重要因素.%Five surveys were carried on in Huizhou segment of Dongjiang River from 2007 to 2010. Total of 69 freshwater fish species belong to 8 orders, 20 families and 58 genera were collected, most of fishes belong to family Cyorinidae ( 39 species ), Bagridae ( 7 ) and Cobitidae ( 5 ). Cirrhina molitorella, Hemiculter leucisculus, Cyprinus carpio and Squaliobarbus curriculus are dominated species in the lower reaches studied. Besides Gambusia affinis, four more exotic species including Tilapia sp. , Labeo rohita, Cirrhina mrigala, and Hypostomus plecostomus were newly recorded. Compared with the data collected in 1980s' , the proportion of sedentary and omnivore species increased, while migratory and carnivore species declined. The result by using autecology matrix analysis showed that carnivore fish species living at gravel bottom and in riffle at

  16. Holocene paleoclimate inferred from salinity histories of adjacent lakes in southwestern Sicily (Italy)

    Science.gov (United States)

    Curry, Brandon; Henne, Paul D.; Mesquita-Joanes, Francesc; Marrone, Federico; Pieri, Valentina; La Mantia, Tommaso; Calò, Camilla; Tinner, Willy

    2016-10-01

    Marked uncertainties persist regarding the climatic evolution of the Mediterranean region during the Holocene. For instance, whether moisture availability gradually decreased, remained relatively constant, or increased during the last 7000 years remains a matter of debate. To assess Holocene limnology, hydrology and moisture dynamics, the coastal lakes Lago Preola and Gorgo Basso, located in southwestern Sicily, were investigated through several stratigraphic analyses of ostracodes, including multivariate analyses of assemblages, transfer functions of salinity, and biochemical analyses of valves (Sr/Ca, δ18O and δ13C). During the early Holocene, the Gorgo Basso and Lago Preola ostracode records are similar. After an initial period of moderate salinity (1690-6100 mg/l from ca. 10,000-8190 cal yr BP), syndepositional or diagenetic dissolution of ostracode valves suggests that salinity declined to Greek civilization took root in Sicily (2600 cal yr BP), and it completely dominates the record during Roman occupation (roughly 2100 to 1700 cal yr BP). These freshwater conditions at Gorgo Basso suggest high effective moisture when evergreen olive-oak forests collapsed in response to increased Greco-Roman land use and fire. Ostracode valve geochemistry (Sr/Ca, δ18O) suggests significant changes in early vs. late Holocene hydrochemistry, either as changes in salinity or in the seasonality of precipitation. Harmonizing the autecological and geochemical data from Gorgo Basso suggests the latter was more likely, with relatively more late Holocene precipitation falling during the spring, summer, and fall, than winter compared to the early Holocene. Our ostracode-inferred paleosalinity data indicate that moisture availability did not decline during the late Holocene in the central Mediterranean region. Instead, moisture availability was lowest during the early Holocene, and most abundant during the late Holocene.

  17. Environmental controls on the distribution and diversity of lentic Chironomidae (Insecta: Diptera) across an altitudinal gradient in tropical South America.

    Science.gov (United States)

    Matthews-Bird, Frazer; Gosling, William D; Coe, Angela L; Bush, Mark; Mayle, Francis E; Axford, Yarrow; Brooks, Stephen J

    2016-01-01

    To predict the response of aquatic ecosystems to future global climate change, data on the ecology and distribution of keystone groups in freshwater ecosystems are needed. In contrast to mid- and high-latitude zones, such data are scarce across tropical South America (Neotropics). We present the distribution and diversity of chironomid species using surface sediments of 59 lakes from the Andes to the Amazon (0.1-17°S and 64-78°W) within the Neotropics. We assess the spatial variation in community assemblages and identify the key variables influencing the distributional patterns. The relationships between environmental variables (pH, conductivity, depth, and sediment organic content), climatic data, and chironomid assemblages were assessed using multivariate statistics (detrended correspondence analysis and canonical correspondence analysis). Climatic parameters (temperature and precipitation) were most significant in describing the variance in chironomid assemblages. Temperature and precipitation are both predicted to change under future climate change scenarios in the tropical Andes. Our findings suggest taxa of Orthocladiinae, which show a preference to cold high-elevation oligotrophic lakes, will likely see range contraction under future anthropogenic-induced climate change. Taxa abundant in areas of high precipitation, such as Micropsectra and Phaenopsectra, will likely become restricted to the inner tropical Andes, as the outer tropical Andes become drier. The sensitivity of chironomids to climate parameters makes them important bio-indicators of regional climate change in the Neotropics. Furthermore, the distribution of chironomid taxa presented here is a vital first step toward providing urgently needed autecological data for interpreting fossil chironomid records of past ecological and climate change from the tropical Andes.

  18. Méthode pragmatique d'évaluation de la réserve en eau des stations forestières et cartographie à l'échelle régionale (Wallonie, Belgique

    Directory of Open Access Journals (Sweden)

    Ridremont, F.

    2011-01-01

    Full Text Available Pragmatic assessment of the water reserve of the forest sites and mapping at the regional scale (Wallonia, Belgium. The assessment of the forest sites water availability constitutes a growing concern following the awareness of the potential impact of climate change on the soil moisture regime. At the present time, the forest managers lack tools for a quantitative estimation of the soil water reserve. This paper presents a simple estimation method that can be adopted on field by foresters. A map of this soil water reserve at the forest site scale has been established for the Southern Belgium. After the inventory of the possible techniques, the "textural method", based on the pedotransfert classes of Jamagne et al. (1977, has been used. The soil profiles from the Aardewerk database have eased the translation of the Jamagne et al. (1977's results in the Belgian textural system. Moreover, the geodatabase of the Digital Soil Map of Wallonia (DSMW, through the typology of the major soil types, has been used as mapping support of the water reserve at the regional scale. Like a first attempt of validation, the result has been compared with the bioindicator character of forest understory vegetation. The regression results show a significant relationship between the soil water reserve and the vegetation estimate, but they also indicate that the water reserve does not explain alone the moisture level expressed by the flora. It emerges that the characterization of the Walloon parent materials will constitute an undeniable support for the development of the proposed method, the transposition of foreign results leading to some bias. The use prospects of this thematic map are multiple: integration as inputs for the autecological modelling, assessment of the moisture regime for the water availability of forest sites and building of sites catalogs; as many tools to guide forest managers in their planning measures.

  19. Positive responses of coastal dune plants to soil conditioning by the invasive Lupinus nootkatensis

    Science.gov (United States)

    Hanslin, Hans Martin; Kollmann, Johannes

    2016-11-01

    Invasive nitrogen-fixing plants drive vegetation dynamics and may cause irreversible changes in nutrient-limited ecosystems through increased soil resources. We studied how soil conditioning by the invasive alien Lupinus nootkatensis affected the seedling growth of co-occurring native plant species in coastal dunes, and whether responses to lupin-conditioned soil could be explained by fertilisation effects interacting with specific ecological strategies of the native dune species. Seedling performance of dune species was compared in a greenhouse experiment using field-collected soil from within or outside coastal lupin stands. In associated experiments, we quantified the response to nutrient supply of each species and tested how addition of specific nutrients affected growth of the native grass Festuca arundinacea in control and lupin-conditioned soil. We found that lupin-conditioned soil increased seedling biomass in 30 out of 32 native species; the conditioned soil also had a positive effect on seedling biomass of the invasive lupin itself. Increased phosphorus mobilisation by lupins was the major factor driving these positive seedling responses, based both on growth responses to addition of specific elements and analyses of plant available soil nutrients. There were large differences in growth responses to lupin-conditioned soil among species, but they were unrelated to selected autecological indicators or plant strategies. We conclude that Lupinus nootkatensis removes the phosphorus limitation for growth of native plants in coastal dunes, and that it increases cycling of other nutrients, promoting the growth of its own seedlings and a wide range of dune species. Finally, our study indicates that there are no negative soil legacies that prevent re-establishment of native plant species after removal of lupins.

  20. Climate variability in south-eastern Australia over the last 1500 years inferred from the high-resolution diatom records of two crater lakes

    Science.gov (United States)

    Barr, Cameron; Tibby, John; Gell, Peter; Tyler, Jonathan; Zawadzki, Atun; Jacobsen, Geraldine E.

    2014-07-01

    Climates of the last two millennia have been the focus of numerous studies due to the availability of high-resolution palaeoclimate records and the occurrence of divergent periods of climate, commonly referred to as the ‘Medieval Climatic Anomaly' and ‘The Little Ice Age'. The majority of these studies are centred in the Northern Hemisphere and, in comparison, the Southern Hemisphere is relatively under-studied. In Australia, there are few high-resolution, palaeoclimate studies spanning a millennium or more and, consequently, knowledge of long-term natural climate variability is limited for much of the continent. South-eastern Australia, which recently experienced a severe, decade-long drought, is one such region. Results are presented of investigations from two crater lakes in the south-east of mainland Australia. Fluctuations in lake-water conductivity, a proxy for effective moisture, are reconstructed at sub-decadal resolution over the past 1500 years using a statistically robust, diatom-conductivity transfer function. These data are interpreted in conjunction with diatom autecology. The records display coherent patterns of change at centennial scale, signifying that both lakes responded to regional-scale climate forcing, though the nature of that response varied between sites due to differing lake morphometry. Both sites provide evidence for a multi-decadal drought, commencing ca 650 AD, and a period of variable climate between ca 850 and 1400 AD. From ca 1400-1880 AD, coincident with the timing of the ‘Little Ice Age', climates of the region are characterised by high effective moisture and a marked reduction in inter-decadal variability. The records provide context for climates of the historical period and reveal the potential for more extreme droughts and more variable climate than that experienced since European settlement of the region ca 170 years ago.

  1. Intraguild predation may reinforce a species-environment gradient

    Science.gov (United States)

    MacNeil, Calum; Dick, Jaimie T. A.

    2012-05-01

    Species-environment gradients are ubiquitous in nature, with studies often partially explaining the replacement of species along such gradients by autecological factors such as differential physiological tolerances. However, lacking direct evidence, the majority of studies only infer some form of inter-specific interaction, often competition, as reinforcing these gradients. There is usually the further implication that environmental factors mediate asymmetries in the interaction. Recognising the lack of explicit experimental considerations of how key inter-specific interactions are modified by the environment, we chose a study system where we were able to bring the species in question into the laboratory and conduct experiments to test hypotheses about gradient-induced asymmetries in an inter-specific interaction. To this end, we tested the hypothesis that a species-salinity gradient may be reinforced by changes in the asymmetry of intraguild predation between two species of amphipod crustaceans with wide salinity tolerances. River and estuary surveys showed that Gammarus duebeni and Gammarus zaddachi have overlapping distributions, with both surviving and reproducing in salinities ranging from freshwater to fully marine. However, the former species is relatively more abundant in low salinities and the latter in higher salinities. In the laboratory, survival of both species was high in all salinities and cannibalism occurred at low frequencies. However, intraguild predation by males on moulted females was asymmetric in favour of G. duebeni at low salinities, this asymmetry completely reversing to favour G. zaddachi at higher salinities. Thus, we provide evidence that this species-environment gradient occurs due to overlapping physiological tolerances and salinity-driven shifts in the asymmetry of a key inter-specific interaction, intraguild predation.

  2. Holocene paleoclimate inferred from salinity histories of adjacent lakes in southwestern Sicily (Italy)

    Science.gov (United States)

    Curry, B Brandon; Henne, Paul; Mezquita-Joanes, Francesc; Marrone, Federico; Pieri, Valentina; La Mantia, Tommaso; Calo, Camilla; Tinner, Willy

    2016-01-01

    Marked uncertainties persist regarding the climatic evolution of the Mediterranean region during the Holocene. For instance, whether moisture availability gradually decreased, remained relatively constant, or increased during the last 7000 years remains a matter of debate. To assess Holocene limnology, hydrology and moisture dynamics, the coastal lakes Lago Preola and Gorgo Basso, located in southwestern Sicily, were investigated through several stratigraphic analyses of ostracodes, including multivariate analyses of assemblages, transfer functions of salinity, and biochemical analyses of valves (Sr/Ca, δ18O and δ13C). During the early Holocene, the Gorgo Basso and Lago Preola ostracode records are similar. After an initial period of moderate salinity (1690–6100 mg/l from ca. 10,000–8190 cal yr BP), syndepositional or diagenetic dissolution of ostracode valves suggests that salinity declined to species capable of rapid swimming and flourishing in waters with low dissolved oxygen levels, became dominant at approximately the time when Greek civilization took root in Sicily (2600 cal yr BP), and it completely dominates the record during Roman occupation (roughly 2100 to 1700 cal yr BP). These freshwater conditions at Gorgo Basso suggest high effective moisture when evergreen olive-oak forests collapsed in response to increased Greco-Roman land use and fire. Ostracode valve geochemistry (Sr/Ca, δ18O) suggests significant changes in early vs. late Holocene hydrochemistry, either as changes in salinity or in the seasonality of precipitation. Harmonizing the autecological and geochemical data from Gorgo Basso suggests the latter was more likely, with relatively more late Holocene precipitation falling during the spring, summer, and fall, than winter compared to the early Holocene. Our ostracode-inferred paleosalinity data indicate that moisture availability did not decline during the late Holocene in the central Mediterranean region. Instead, moisture

  3. A natural resource condition assessment for Sequoia and Kings Canyon National Parks: Appendix 11a: giant sequoias

    Science.gov (United States)

    York, Robert A.; Stephenson, Nathan L.; Meyer, Marc; Hanna, Steve; Tadashi, Moody; Caprio, Anthony C.; Battles, John J.

    2013-01-01

    For natural resource managers in the southern Sierra Nevada, giant sequoia requires very little introduction. It receives great attention as an icon of western forests and as a common namesake with the areas where it occurs. While it is a single component of a very complex system, its attention in this assessment and in general is well deserved. Giant sequoia is one of the few "destination species" that attracts a wide swath of the public by nature of it simply being present. It draws people, who otherwise may not travel, to a natural environment. The result is an expansion of the public’s sense of natural resource stewardship. Because park managers could not achieve their mission without public support, this fostering role of giant sequoia is critical for park natural resources and is important for natural resources in general. Despite its social relevance and physical size, we re-emphasize here that the giant sequoia resource is a relatively small component of the ecosystems of the southern Sierra Nevada. As is the case with all of the resources assessed in the NRCA, we focus on giant sequoia with the understanding that other resources will be considered simultaneously when evaluating management decisions that impact giant sequoia. While we attempt to explicitly address the interaction of giant sequoia with other resources and stressors, we also realize that ultimately managers will integrate much more information than is presented here when making decisions that influence giant sequoia. The autecology and management issues surrounding giant sequoia have been thoroughly reviewed elsewhere (Harvey et al. 1980, Aune 1994, Stephenson 1996). Stephenson (1996), in particular, should be reviewed when considering any management decisions that potentially impact giant sequoia. For those who may not be familiar with giant sequoia ecology, a summary of basic information is provided in a table below. In some parts of this assessment, we reproduce text from Stephenson

  4. On the integration of ecology in remote sensing science

    Science.gov (United States)

    Dobrowski, Solomon Zev

    large improvements in map accuracy. This work provides an avenue for ecologists to incorporate knowledge of species autecology into the classification problem and thus provides for a stronger link between the disciplines of remote sensing and applied vegetation science.

  5. The ecology of xenophyophores (Protista) on eastern Pacific seamounts

    Science.gov (United States)

    Levin, Lisa A.; Thomas, Cynthia L.

    1988-12-01

    Large, agglutinating protozoans of the class Xenophyophorea are the dominant epifaunal organisms on soft and hard substrates of many bathyal seamounts in the eastern Pacific Ocean off Mexico. Observations made with the submersible Alvin and remotely towed camera sleds on 17 seamounts at 31°, 20°, 13° and 10°N revealed more than ten distinct xenophyophore test morphologies. Most of these appear to represent previously undescribed species. Reticulate forms are numerically dominant at 20°, 13° and 10°N. Xenophyophore abundances increase with decreasing latitude, being rare at 30°N, present at densities of 0.1-1.0 m -2 at 20° and 13°N and often exceeding 1.0 m -2 at 10°N, occasionally reaching 10-18 m -2. Highest concentrations are observed on caldera floors near the base of steep caldera walls, at depths between 1700 and 2500 m. Most individuals select sand-size pelagic foraminiferan tests (63-500 μm) and exclude pebble, silt and clay-size particles for test construction. Xenophyophore on seamounts modify the structure of metazoan communities and may play a role in maintenance of infaunal diversity. Twenty-seven xenophyophore tests were found to provide habitat for 16 major macrofaunal taxa (152 individuals) and three meiofaunal taxa (333 individuals). The presence of xenophyophores also enhances the abundance of isopods, tanaids, ophiuroids, nematodes and harpacticoid copepods dwelling in sediments surrounding the tests. Mobile megafauna are attracted to sediment beneath and adjacent to xenophyophores. We suggest that xenophyophores, which are abundant on many topographic features in deep water (e.g. guyots, trenches, canyons and continental slopes), are a functionally important component of deep-sea benthic communities and require further autecological and synecological investigation.

  6. The future of Arctic benthos: Expansion, invasion, and biodiversity

    Science.gov (United States)

    Renaud, Paul E.; Sejr, Mikael K.; Bluhm, Bodil A.; Sirenko, Boris; Ellingsen, Ingrid H.

    2015-12-01

    One of the logical predictions for a future Arctic characterized by warmer waters and reduced sea-ice is that new taxa will expand or invade Arctic seafloor habitats. Specific predictions regarding where this will occur and which taxa are most likely to become established or excluded are lacking, however. We synthesize recent studies and conduct new analyses in the context of climate forecasts and a paleontological perspective to make concrete predictions as to relevant mechanisms, regions, and functional traits contributing to future biodiversity changes. Historically, a warmer Arctic is more readily invaded or transited by boreal taxa than it is during cold periods. Oceanography of an ice-free Arctic Ocean, combined with life-history traits of invading taxa and availability of suitable habitat, determine expansion success. It is difficult to generalize as to which taxonomic groups or locations are likely to experience expansion, however, since species-specific, and perhaps population-specific autecologies, will determine success or failure. Several examples of expansion into the Arctic have been noted, and along with the results from the relatively few Arctic biological time-series suggest inflow shelves (Barents and Chukchi Seas), as well as West Greenland and the western Kara Sea, are most likely locations for expansion. Apparent temperature thresholds were identified for characteristic Arctic and boreal benthic fauna suggesting strong potential for range constrictions of Arctic, and expansions of boreal, fauna in the near future. Increasing human activities in the region could speed introductions of boreal fauna and reduce the value of a planktonic dispersal stage. Finally, shelf regions are likely to experience a greater impact, and also one with greater potential consequences, than the deep Arctic basin. Future research strategies should focus on monitoring as well as compiling basic physiological and life-history information of Arctic and boreal taxa, and

  7. A Kinetic and Factorial Approach to Study the Effects of Temperature and Salinity on Growth and Toxin Production by the Dinoflagellate Alexandrium ostenfeldii from the Baltic Sea

    Science.gov (United States)

    Salgado, Pablo; Vázquez, José A.; Riobó, Pilar; Franco, José M.; Figueroa, Rosa I.; Kremp, Anke; Bravo, Isabel

    2015-01-01

    Alexandrium ostenfeldii is present in a wide variety of environments in coastal areas worldwide and is the only dinoflagellate known species that produces paralytic shellfish poisoning (PSP) toxins and two types of cyclic imines, spirolides (SPXs) and gymnodimines (GYMs). The increasing frequency of A. ostenfeldii blooms in the Baltic Sea has been attributed to the warming water in this region. To learn more about the optimal environmental conditions favoring the proliferation of A. ostenfeldii and its complex toxicity, the effects of temperature and salinity on the kinetics of both the growth and the net toxin production of this species were examined using a factorial design and a response-surface analysis (RSA). The results showed that the growth of Baltic A. ostenfeldii occurs over a wide range of temperatures and salinities (12.5–25.5°C and 5–21, respectively), with optimal growth conditions achieved at a temperature of 25.5°C and a salinity of 11.2. Together with the finding that a salinity > 21 was the only growth-limiting factor detected for this strain, this study provides important insights into the autecology and population distribution of this species in the Baltic Sea. The presence of PSP toxins, including gonyautoxin (GTX)-3, GTX-2, and saxitoxin (STX), and GYMs (GYM-A and GYM-B/-C analogues) was detected under all temperature and salinity conditions tested and in the majority of the cases was concomitant with both the exponential growth and stationary phases of the dinoflagellate’s growth cycle. Toxin concentrations were maximal at temperatures and salinities of 20.9°C and 17 for the GYM-A analogue and > 19°C and 15 for PSP toxins, respectively. The ecological implications of the optimal conditions for growth and toxin production of A. ostenfeldii in the Baltic Sea are discussed. PMID:26636674

  8. Seasonal succession of the travertine-forming desmid Oocardium stratum.

    Science.gov (United States)

    Linhart, Caroline; Schagerl, Michael

    2015-12-01

    The calcifying Conjugatophyte Oocardium stratum occurs exclusively in spring-associated limestones (SAL) with active meteogene limestone deposition. The macroscopic colonies of Oocardium stratum form hemispherical, pinhead-like structures with a diameter of 0.5-2.0 mm. As its autecology is still poorly understood, we focused on the seasonal development of Oocardium stratum and linked environmental factors to its abundance. The study was conducted in a rivulet in Lunz/See (Austria) for 16 months on a weekly (growing season) to monthly (winter season) basis. Oocardium colonies were found throughout the whole year, with maximum abundance during the mid-summer months July and August. Repeated macro-mapping of three SAL sites measuring 750 cm(2) each showed a maximum Oocardium cover of around 30% in August; two smaller peaks developed in early summer and late autumn with ~10% cover. Diatom mats dominated by Cymbella excisiformis occurred in spring, autumn and winter, with more than 75% cover. The seasonal change between Oocardium and diatoms in limestone-precipitating springs causes a typical sequence pattern of limestone layers. Redundancy analysis revealed water temperature and bicarbonate content as the main structuring factors; these control the occurrence and growth of Oocardium, reflecting season as a background variable. Optimum growth conditions for Oocardium were an alkalinity around 4.7 meq · L(-1) and a water temperature around 13°C. Site openness, nitrate and dissolved carbon dioxide were inversely related to Oocardium biomass, the opposite for diatoms. Other environmental factors such as total ions or soluble reactive phosphorus had no significant influence on Oocardium stratum abundance. PMID:26987001

  9. Environmental controls on the distribution and diversity of lentic Chironomidae (Insecta: Diptera) across an altitudinal gradient in tropical South America.

    Science.gov (United States)

    Matthews-Bird, Frazer; Gosling, William D; Coe, Angela L; Bush, Mark; Mayle, Francis E; Axford, Yarrow; Brooks, Stephen J

    2016-01-01

    To predict the response of aquatic ecosystems to future global climate change, data on the ecology and distribution of keystone groups in freshwater ecosystems are needed. In contrast to mid- and high-latitude zones, such data are scarce across tropical South America (Neotropics). We present the distribution and diversity of chironomid species using surface sediments of 59 lakes from the Andes to the Amazon (0.1-17°S and 64-78°W) within the Neotropics. We assess the spatial variation in community assemblages and identify the key variables influencing the distributional patterns. The relationships between environmental variables (pH, conductivity, depth, and sediment organic content), climatic data, and chironomid assemblages were assessed using multivariate statistics (detrended correspondence analysis and canonical correspondence analysis). Climatic parameters (temperature and precipitation) were most significant in describing the variance in chironomid assemblages. Temperature and precipitation are both predicted to change under future climate change scenarios in the tropical Andes. Our findings suggest taxa of Orthocladiinae, which show a preference to cold high-elevation oligotrophic lakes, will likely see range contraction under future anthropogenic-induced climate change. Taxa abundant in areas of high precipitation, such as Micropsectra and Phaenopsectra, will likely become restricted to the inner tropical Andes, as the outer tropical Andes become drier. The sensitivity of chironomids to climate parameters makes them important bio-indicators of regional climate change in the Neotropics. Furthermore, the distribution of chironomid taxa presented here is a vital first step toward providing urgently needed autecological data for interpreting fossil chironomid records of past ecological and climate change from the tropical Andes. PMID:26811777

  10. Population demographics of catostomids in large river ecosystems: effects of discharge and temperature on recruitment dynamics and growth

    Science.gov (United States)

    Quist, M.C.; Spiegel, J.R.

    2011-01-01

    substrates. Temperature was weakly related to growth of catostomids; however, discharge explained a substantial amount of the variation in growth of nearly all species. Results of this study provide important information on the autecology of catostomids that can be used for comparison among species and systems. These data also suggest that connection of rivers with their floodplain is an important feature for catostomids in temperate river systems.

  11. Sunflower (Helianthus annuus) pollination in California's Central Valley is limited by native bee nest site location.

    Science.gov (United States)

    Sardiñas, Hillary S; Tom, Kathleen; Ponisio, Lauren Catherine; Rominger, Andrew; Kremen, Claire

    2016-03-01

    within sunflower fields, with edges receiving higher coverage than field centers. To generate more accurate maps of services, we advocate directly measuring the autecology of ecosystem service providers, which vary by crop system, pollinator species, and region. Improving estimates of the factors affecting pollinator populations can increase the accuracy of pollination service maps and help clarify the influence of farming practices on wild bees occurring in agricultural landscapes. PMID:27209786

  12. DICKINSARTELLA FAUNA FROM THE SAIWAN FORMATION (OMAN: A BIVALVE FAUNA TESTIFYING TO THE LATE SAKMARIAN (EARLY PERMIAN CLIMATIC AMELIORATION ALONG THE NORTH-EASTERN GONDWANAN FRINGE.

    Directory of Open Access Journals (Sweden)

    CRISTIANO LARGHI

    2005-11-01

    Dickinsartella Fauna and confirms the correlation between Arabian and Australian series already remarked by previous authors. The "Dickinsartella fauna" is the first bivalve fauna testifying to the climatic amelioration gradually affecting the North-Eastern Gondwanan fringe at the end of the Early Permian glacial events. This pioneer fauna spread out, probably in a cool-temperate climate, on the substrate provided by the mid-Sakmarian (basal Sterlitamakian transgression, connected with the final stages of the Gondwanan deglaciation and/or with initial sea-floor spreading in the Neotethys. In the present paper some remarks on the autecology of the new species from the "Pachycyrtella bed" are also discussed.

  13. Assessment of Nonnative Invasive Plants in the DOE Oak Ridge National Environmental Research Park

    Energy Technology Data Exchange (ETDEWEB)

    Drake, S.J.

    2002-11-05

    forms. Results of this research can be used to prioritize management and research activities related to these invasive taxa on the Research Park as a whole and for specific Natural or Reference Areas. Additional research on the autecology and synecology of each species surveyed is suggested. In particular, research should focus on assessing the impacts of these species on the invaded plant and animal communities and ecosystems. Finally, this ranking system could be used to similarly rank the many other nonnative, invasive species present on the Research Park not included in this study.

  14. The early to mid-Miocene environment of Antarctica

    Science.gov (United States)

    Ashworth, A. C.; Lewis, A.

    2012-12-01

    assemblage is at treeline and higher on Isla Navarino (55°S) at the southern tip of South America. By mid-Miocene, the upland tundra biota was less diverse, most notably in the number of angiosperm taxa. Based on the autecology and geographic distributions of the descendants of the fossil biota which survive in the subantarctic islands, South America and Tasmania, there was a decline of mean summer temperatures from c. 6°C to c. 4°C from the early to the mid-Miocene. During the early Miocene, the MST of the TAM was c.19°C warmer than today. A paleotemperature estimate based on leaf waxes from a Ross Sea core is for a MST 11°C warmer than today which seems low considering it is based on a near sea-level vegetation. A recent paper utilizing a salt-hydration process to provide adequate moisture to support a Miocene tundra biota is based on erroneous data. The Miocene climate was wet with an annual precipitation of at least 3000 mm. A recent report of the possible survival of vegetation in the Taylor Valley until the Pliocene, based on the discovery of 5 Ma wood-like forms in a DVDP core, is improbable. Even if wood can be definitively identified from the Pliocene deposits it is likely to be reworked Miocene wood from uplands in the TAM (e.g. Friis Hills). Research supported by NSF OPP 0739693.

  15. Population dynamics and bioenergetics of a fossorial herbivore, Thomomys talpoides (Rodentia: Geomyidae), in a spruce-fir sere

    Science.gov (United States)

    Andersen, Douglas C.; MacMahon, James A.

    1981-01-01

    through the first year was comparable to adult annual rates. The fertility rate was 3.75 young • female-1 • yr-1. The energy supply and demand analyses indicate that the growth of Thomomys talpoides populations in the early seral stages is seldom directly limited by the amount of food present. From our demographic, environmental, and autecological studies we conclude that stochastic events associated with weather affect energy acquisition (burrowing) rates, and thus survivorship. In montane environments, such events may prevent populations from attaining sizes at which territorial behavior would hypothetically limit further increases. The energy flow through the meadow population at moderate to high )1976-1977) densities (at least 1100 MJ • ha-1 • yr-1) indicates that pocket gophers are proficient energy movers relative to non-fossorial small mammals. Subalpine T. talpoides populations appear commonly to attain such densities. More than 30% of the annual primary productivity allocated to belowground parts of meadow forbs may be consumed by gophers.

  16. New data on the FWF project P20018-N10: The Puez key-section in the Dolomites (Southern Alps; N-Italy)

    Science.gov (United States)

    Lukeneder, A.; Mayrhofer, S.

    2009-04-01

    section especially suited to accurately study the vertical ammonite distribution. The main focus in the future will be to investigate in detail the stratigraphic framework of the Puez section. Bed-by-bed collecting is required to obtain crucial data on the ammonoid distribution and occurrence (range). Epizoans. Lukeneder (2008) presented the most recent investigations on this topic. Lower Cretaceous (Valanginian - Aptian) deposits of the Puez locality in yield remarkable amounts of specimens of different ammonoid taxa (28 genera, n = 424) showing unique epifaunal encrustations by the scleractinian, ahermatypic solitary coral ?Cycloseris Lamarck, 1801. The pattern of infestation clearly documents a preference of the adherent taxa for the outer shell surface of the ammonoids, whereas the inner surface remains barren. Such a remarkable metabiotic dwelling palaeocommunity is described for the first time. The ammonoid shell of the dead animal sank to the sea bottom and became encrusted by the coral larvae, what is documented by the location of the epibionts only on one side of the deposited ammonoid shells. The relation between the latter fossil groups is reported for the first time. The exact stratigraphically dating of the ammonoid fauna allows synchronously to clear the age of the infested corals and the autecological history of this new ammonid/coral palaeocommunity. The symbiotic ammonoid-coral relation from the Dolomites exists from the Valanginian to Aptian times. Future work. A cooperative project (FWF project P20018-N10; 22 international scientists): An Integrative High Resolution Project. Macro- and Microfossils, Isotopes, Litho-, Cyclo-, Magneto-and Biostratigraphy as Tools for Investigating the Lower Cretaceous within the Dolomites (Southern Alps, Northern Italy) -The Puez Area as a New Key Region of the Tethyan Realm), is on the way since 2008 by the Natural History Museum in Vienna and the Southern Tyrol ‘Naturmuseum Südtirol' in Bozen. References Lukeneder A

  17. Feeding behavior of Frontonia leucas (Ehrenberg (Protozoa, Ciliophora, Hymenostomatida under different environmental conditions in a lotic system Comportamento alimentar de Frontonia leucas (Ehrenberg (Protozoa, Ciliophora, Hymenostomatida sob diferentes condições ambientais em um sistema lótico

    Directory of Open Access Journals (Sweden)

    Roberto Júnio P. Dias

    2006-09-01

    Full Text Available The objective of this study was to record and describe the morphological changes and the ingestion mechanisms of Frontonia leucas (Ehrenberg, 1833 according to the food type and to relate the food ingested with the different environmental conditions in a lotic system, namely São Pedro stream, located in the municipality of Juiz de Fora, Minas Gerais, Brazil. We sampled three points on a monthly basis from August 2002 to June 2003, each of which receiving different levels of untreated sewage. We prepared culture media for the ciliate specimens containing filtered water from each point and the types of food observed inside F. leucas (cyanobacteria, diatoms, desmids and testate amoebas. We observed the ingestion mechanisms of F. leucas in vivo, under a phase contrast optical microscope, using instantaneous sampling and sequence sampling as behavior observation methods, noting the following parameters: dissolved oxygen concentration, pH, conductivity and water temperature. We noted the F. leucas ciliates ingesting diatoms and desmids at collection point 1 and filamentous cyanobacteria, testate amoebas (Arcella and Centropyxis and rotifers at points 2 and 3. The present work records for the first time the ingestion of testate amoebas of the genus Centropyxis by F. leucas. We noted five ingestion mechanisms by F. leucas while feeding on cyanobacteria and testate amoebas of the genus Centropyxis, three of these related to the ciliary action and two involving physical changes in the cytoplasm. For ingestion of diatoms, desmid (Closterium and Arcella, the mechanisms involving ciliary action alone were sufficient for ingestion, since these preys are smaller than the ciliate under study. The autecological data registered for F. leucas were 1.98-8.01 mg l-1 O2, pH 6.9-8.73, 58-390 µS/cm and 19.5-26.2ºC, confirming its ample ecological valence.O objetivo do presente trabalho foi registrar e descrever as alterações morfológicas e os mecanismos de ingest

  18. Overview of the classification, lack, and its perfection of ecological experiments at home and abroad%生态学实验的分类概况、欠缺及其完善

    Institute of Scientific and Technical Information of China (English)

    肖显静; 林祥磊

    2013-01-01

    various ecological sub-discipline experiments: according to the level of organization of the object studied, the ecological experiments can be divided into autecology experiments, population ecology experiments, community ecology experiments, ecosystem ecology experiments, landscape ecology experiments, and global ecology experiments; according to sub-discipline formed by the intersection of ecology and biological sciences, the ecological experiments can be divided into the physiological ecology experiments, genetic ecology experiments, behavioral ecology experiments, animal ecology experiments, plant ecology experiments, microbial ecology experiment, and so on; according to the motives of the ecology experimental research, the ecological experiments can be divided into theoretical ecology experiments and applied ecology experiments. Second, based on the teaching needs, the ecological experiments can be divided into basic experiments, comprehensive experiments and research experiments. Third, the ecological experiments can be divided into a series of experimental categories based on the spatial and temporal characteristics, object characteristics, and role characteristics of the ecological experiments. According to places where the experiments are implemented, the ecological experiments can be divided into field experiments and laboratory experiments; according to whether the experiments are qualitative or quantitative, the ecological experiments can be divided into qualitative experiments and quantitative (mensurative) experiments; according to whether naturally occurring interferences are used as treatments, the ecological experiments can be divided into natural experiments and unnatural experiment; according to whether the experiments directly act on the objective object, the ecological experiments can be divided into direct experiments and indirect experiments; according to the number of ecological factors to be tested, the ecological experiments can be divided into