Sample records for autecology

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

    Porter, Stephen D.


    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. Reconstructing riverine mesohabitat unit composition using fish community data and an autecology matrix. (United States)

    Suen, J P; Su, W C


    This research proposes a simplified method for estimating the mesohabitat composition that would favour members of a given set of aquatic species. The simulated composition of four types of mesohabitat units (deep pool, shallow pool, deep riffle and shallow riffle) could guide the design of in-stream structures in creating pool-riffle systems with ecological reference. Fish community data and an autecology matrix are used to support the development of a stream mesohabitat simulation based on regression models for reaches in mid to upper-order streams. The fish community-mesohabitat model results constitute a reference condition that can be used to guide stream restoration and ecological engineering decisions aimed at maintaining the natural ecological integrity and diversity of rivers.

  3. Plant indicator values as a tool for land mollusc autecology assessment (United States)

    Horsák, Michal; Hájek, Michal; Tichý, Lubomír; Juřičková, Lucie


    The aim of this paper was to utilize Ellenberg's plant indicator system for assessing mollusc autecology and to highlight possibilities and advantages of that approach in the case of fen mollusc communities. Molluscs and plants from 137 fen sites in the Western Carpathian Mountains were recorded quantitatively from homogeneous areas of 16 m 2. Water conductivity and pH were measured in the field. Values of Ellenberg's "light, temperature, continentality, moisture, soil reaction, and nutrients" were estimated for each site. The whole data set was processed using ordinations (PCA, DCA, and CCA) and generalized additive models (GAMs). We observed a strong correlation between water pH and Ellenberg soil reaction estimated by plant indicator values ( r = 0.72, P bioindication and nature conservation. Our data and approach could help design appropriate conservation management regimes for threatened snail species. We propose that our approach will be useful also in ecological studies of other animal groups.

  4. Distribution, autecology and biogeography of Dryopidae and Elmidae (Coleoptera, Dryopoidea in the Balearic Islands

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    Rico, E.


    Full Text Available The distribution of the Dryopidae and Elmidae in the Balearic Islands was studied. Three species of Dryopidae —Dryops algiricus (Lucas, 1949, D. gracilis (Karsch, 1881 and D. sulcipennis (Costa, 1883— and one of Elmidae —Oulimnius echinatus Berthélemy, 1979— were found. Bibliographical data of other three species of Dryopidae exist, but their presence is either refuted —Dryops lutulentus (Erichson, 1847— or requires confirmation —Dryops luridus (Erichson, 1847 and D. rufipes (Krynicki, 1832—. Dryops gracilis and D. sulcipennis are recorded for first time in the archipelago. The first autecological data of the different species in the archipelago and a biogeographical analysis are provided.

    Se realiza un estudio sobre la distribución de los Dryopidae y Elmidae en las islas Baleares. Tres especies de Dryopidae —Dryops algiricus (Lucas, 1949, D. gracilis (Karsch, 1881 y D. sulcipennis (Costa, 1883— y una de Elmidae —Oulimnius echinatus Berthélemy, 1979— han sido halladas. Existen datos bibliográficos de otras tres especies de Dryopidae, pero su presencia es excluida —Dryops lutulentus (Erichson, 1847— o se considera que debe ser confirmada —Dryops luridus (Erichson, 1847 y D. rufipes (Krynicki, 1832—. Dryops gracilis y D. sulcipennis se citan por primera vez en el archipiélago. Se aportan los primeros datos sobre la autoecología de las diferentes especies en las islas y se realiza un análisis biogeográfico.

  5. The morphological and autecological properties of Salvia rosifolia Sm. (Lamiaceae) grown in Erzurum and its environs in Turkey. (United States)

    Kaya, Yusuf; Aksakal, Ozkan


    The aim of this study was to determine the morphological and autecological characteristics of Salvia rosifolia Sm. which is an endemic plant (Lamiaceae) distributed in Erzurum and its environs. Morphologically, it was observed that the species had a perennial root system, the herbaceous stem was ascending, unbranched, leaves pinnatisect, oblong-eliptic, glandular and eglandular hairs were present on the both surface of leaves. Bracts were ovate-acuminate and bracteols lanceolate. It was observed that calyx was campanulate and corolla bilabiate and also species contained two A type of stamen. Ecologically, the chemical and physical analysis was carried out on soil and plant samples collected from 22 different localities in Erzurum and its environs. Present results showed that the plant generally prefers loamy, sandy-loamy and sandy-clayey-loam textural soils, with a slightly alkaline or neutral pH. They also preferred non-saline or slightly saline soils which were both medium and rich calcium carbonate. The result obtained from soil and plant analyses were evaluated statistically and it was found that there was a relation between the quantities of phosphorus, nitrogen and potassium and plant abundance and distribution.

  6. 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)


    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.

  7. Autecology of « cèpes ». Perspectives for the management of forest ecosystems


    Larrieu, Laurent; Guinberteau, Jacques; Rigou, Laurent; Abourouh, Mohamed; Zimmerlin, Anaïs; Corriol, Gilles; Bonet, José-Antonio; De Aragon, Juan Martinez; Martinez Pena, Fernando; Rondet, Jean


    L’analyse des répartitions chorologiques et écologiques des Boletus de la section Edules montre qu’il s’agit d’espèces à large amplitude, depuis l’Afrique du nord jusqu’au Nord du Boréal. Pour chacune des espèces du groupe, cette large répartition s’accompagne d’une grande diversité à la fois des plantes-hôtes, des habitats et des conditions édaphiques. Certaines caractéristiques des écosystèmes forestiers sont plus favorables à la production de carpophores, en particulier les phases à forte ...

  8. Autecology of an arsenite chemolithotroph: sulfide constraints on function and distribution in a geothermal spring. (United States)

    D'Imperio, Seth; Lehr, Corinne R; Breary, Michele; McDermott, Timothy R


    Previous studies in an acid-sulfate-chloride spring in Yellowstone National Park found that microbial arsenite [As(III)] oxidation is absent in regions of the spring outflow channel where H(2)S exceeds approximately 5 microM and served as a backdrop for continued efforts in the present study. Ex situ assays with microbial mat samples demonstrated immediate As(III) oxidation activity when H(2)S was absent or at low concentrations, suggesting the presence of As(III) oxidase enzymes that could be reactivated if H(2)S is removed. Cultivation experiments initiated with mat samples taken from along the H(2)S gradient in the outflow channel resulted in the isolation of an As(III)-oxidizing chemolithotroph from the low-H(2)S region of the gradient. The isolate was phylogenetically related to Acidicaldus and was characterized in vitro for spring-relevant properties, which were then compared to its distribution pattern in the spring as determined by denaturing gradient gel electrophoresis and quantitative PCR. While neither temperature nor oxygen requirements appeared to be related to the occurrence of this organism within the outflow channel, H(2)S concentration appeared to be an important constraint. This was verified by in vitro pure-culture modeling and kinetic experiments, which suggested that H(2)S inhibition of As(III) oxidation is uncompetitive in nature. In summary, the studies reported herein illustrate that H(2)S is a potent inhibitor of As(III) oxidation and will influence the niche opportunities and population distribution of As(III) chemolithotrophs.

  9. Mononchoides composticola n. sp. (Nematoda:Diplogastridae) associated with composting processes: morphological, molecular and autecological characterisation

    NARCIS (Netherlands)

    Steel, H.; Moens, T.; Scholaert, A.; Boshoff, M.; Houthoofd, W.; Bert, W.


    Mononchoides composticola n. sp. was isolated from compost and is described based on light and scanning electron microscopy, supplemented with SSU rDNA sequence data. It is characterised by the following features: a denticulate ridge in addition to the dorsal claw-like tooth, a small tooth-like swel

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

    Energy Technology Data Exchange (ETDEWEB)

    Hinds, W.T.


    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)

  11. 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


    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.

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

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    Svein Birger WÆRVÅGEN


    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.

  13. 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

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    Itayguara Ribeiro da Costa


    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.

  14. 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

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    Mazandarani Masoumeh


    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.

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

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    Barnett A.


    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.

  16. 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


    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....

  17. Demecology in the Cambrian: synchronized molting in arthropods from the Burgess Shale


    Haug, Joachim T; Caron, Jean-Bernard; Haug, Carolin


    Background The Burgess Shale is well known for its preservation of a diverse soft-bodied biota dating from the Cambrian period (Series 3, Stage 5). While previous paleoecological studies have focused on particular species (autecology) or entire paleocommunities (synecology), studies on the ecology of populations (demecology) of Burgess Shale organisms have remained mainly anecdotal. Results Here, we present evidence for mass molting events in two unrelated arthropods from the Burgess Shale Wa...

  18. Genomics and ecophysiology of heterotrophic nitrogen-fixing bacteria isolated from estuarine surface water

    DEFF Research Database (Denmark)

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


    ABSTRACT The ability to reduce atmospheric nitrogen (N 2) to ammonia, known as N 2 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 N 2-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 N 2 fixation by three environmentally ...

  19. Trogulus martensi Chemini, 1983 im Raum Basel (Arachnida, Opiliones, Trogulidae

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    Weiss, Ingmar


    Full Text Available Trogulus martensi Chemini, 1983, formerly thought to be endemic in northern Italy, is recorded from several places near Basle (first records in Switzerland and France. The species is close to T. galasensis Avram, 1971. Important differences to the syntopic T. closanicus Avram, 1971 (first published record in Fance and the sympatric T. nepaeformis (Scopoli, 1763 are shown and discussed. Additional biometric, autecological and phenological data of Trogulus martensi are presented.

  20. 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


    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.

  1. Relationships between diatoms and tidal environments in Oregon and Washington, USA (United States)

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


    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.

  2. (United States)

    Remmert, Hermann


    Synchrony of diurnal activity patterns seems to have evolved entirely between groups of species. No well established case of synchrony is known which involves only two species. The interdependence of activity patterns based on diurnal rhythms is a phenomenon well known in autecology, e.g. between flowers and their pollinators, parasites and their hosts, predators and their prey.At different daytimes there are completely different food chains in one and the same biotope.The few existing quantitative investigations reveal that 1. strong selective pressure can limit the diurnal activity of a species; 2. the productivity in a biotope may reach a maximum when the daily feeding time of its predators is restricted. This seems to hold, e.g., for the marine plancton.

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

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    A. Whateley


    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.

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


    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

  5. 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 (United States)

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


    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.

  6. Progress Towards an Interdisciplinary Science of Plant Phenology: Building Predictions Across Space, Time and Species Diversity (United States)

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


    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.

  7. Morphology and function in the Cambrian Burgess Shale megacheiran arthropod Leanchoilia superlata and the application of a descriptive matrix

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    Haug Joachim T


    Full Text Available Abstract Background Leanchoilia superlata is one of the best known arthropods from the middle Cambrian Burgess Shale of British Columbia. Here we re-describe the morphology of L. superlata and discuss its possible autecology. The re-description follows a standardized scheme, the descriptive matrix approach, designed to provide a template for descriptions of other megacheiran species. Results Our findings differ in several respects from previous interpretations. Examples include a more slender body; a possible hypostome; a small specialised second appendage, bringing the number of pairs of head appendages to four; a further sub-division of the great appendage, making it more similar to that of other megacheirans; and a complex joint of the exopod reflecting the arthropod’s swimming capabilities. Conclusions Different aspects of the morphology, for example, the morphology of the great appendage and the presence of a basipod with strong median armature on the biramous appendages indicate that L. superlata was an active and agile necto-benthic predator (not a scavenger or deposit feeder as previously interpreted.

  8. Does beach nourishment have long-term effects on intertidal macroinvertebrate species abundance? (United States)

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


    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.

  9. The integration of climate change, spatial dynamics, and habitat fragmentation: A conceptual overview. (United States)

    Holyoak, Marcel; Heath, Sacha K


    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.

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

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    P. Paquet


    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.

  11. Ecological plasticity of Trichoderma fungi in leached chernozem (United States)

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


    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.

  12. Carving out turf in a biodiversity hotspot: multiple, previously unrecognized shrew species co-occur on Java Island, Indonesia. (United States)

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


    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.

  13. Stomach emptiness in fishes: Sources of variation and study design implications (United States)

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


    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. 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


    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

  15. A natural resource condition assessment for Sequoia and Kings Canyon National Parks: Appendix 11a: giant sequoias (United States)

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


    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

  16. Climate variability in south-eastern Australia over the last 1500 years inferred from the high-resolution diatom records of two crater lakes (United States)

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


    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.

  17. Die epigäische Spinnenfauna (Arachnida, Araneae in Sandrasen, Borstgrasrasen und Ruderalfluren im Naturschutzgebiet „Alter Flugplatz Karlsruhe“

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    Hemm, Verena


    Full Text Available Epigeic spiders were sampled using pitfall traps during one year in an anthropogenic open site within the city of Karlsruhe (Alter Flugplatz Karlsruhe. The area, historically used as a military parade ground and airport, is protected as a Special Area of Conservation (SAC within the Natura 2000 network of the EU and since 2010 as a German nature reserve. We were interested in the diversity, assemblage structure and distribution of spider species within the area and investigated three different plant formations: sparse grass-dominated vegetation with frequent open sand patches (sandy turf, closed grassland dominated by the mat-grass (Nardus stricta and ruderal vegetation with blackberry bushes. 123 species were identified from these captures, including many specialists of xerothermic habitats and rare and endangered species like Alopecosa striatipes, Agroeca lusatica, Haplodrassus dalmatensis, Styloctetor romanus, Typhochrestus simoni and Xysticus striatipes as well as extremely rare species of unclassified red list status like Mysmenella jobi, Theonoe minutissima and Zora parallela. The three investigated habitat types were quite similar concerning α-diversity, while measures of β-diversity indicated a strong species turnover. By performing an ecological habitat analysis (using autecological data on spiders essential differences between the three habitat types could not be discovered, especially not between mat-grass and sandy turf. However, analysing the guild structures showed that different ways of using habitat resources dominated in the different habitat types. For Nardus-grassland several species could be identified as indicator species. While many xero- and photophiles live in the open grassland, the stenotopic psammophiles of inland dunes in the region were not found. The ruderal area houses a mix of grassland- and forest species.

  18. Positive responses of coastal dune plants to soil conditioning by the invasive Lupinus nootkatensis (United States)

    Hanslin, Hans Martin; Kollmann, Johannes


    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.

  19. Taking ecological function seriously: soil microbial communities can obviate allelopathic effects of released metabolites.

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    Harleen Kaur

    Full Text Available BACKGROUND: Allelopathy (negative, plant-plant chemical interactions has been largely studied as an autecological process, often assuming simplistic associations between pairs of isolated species. The growth inhibition of a species in filter paper bioassay enriched with a single chemical is commonly interpreted as evidence of an allelopathic interaction, but for some of these putative examples of allelopathy, the results have not been verifiable in more natural settings with plants growing in soil. METHODOLOGY/PRINCIPAL FINDINGS: On the basis of filter paper bioassay, a recent study established allelopathic effects of m-tyrosine, a component of root exudates of Festuca rubra ssp. commutata. We re-examined the allelopathic effects of m-tyrosine to understand its dynamics in soil environment. Allelopathic potential of m-tyrosine with filter paper and soil (non-sterile or sterile bioassays was studied using Lactuca sativa, Phalaris minor and Bambusa arundinacea as assay species. Experimental application of m-tyrosine to non-sterile and sterile soil revealed the impact of soil microbial communities in determining the soil concentration of m-tyrosine and growth responses. CONCLUSIONS/SIGNIFICANCE: Here, we show that the allelopathic effects of m-tyrosine, which could be seen in sterilized soil with particular plant species were significantly diminished when non-sterile soil was used, which points to an important role for rhizosphere-specific and bulk soil microbial activity in determining the outcome of this allelopathic interaction. Our data show that the amounts of m-tyrosine required for root growth inhibition were higher than what would normally be found in F. rubra ssp. commutata rhizosphere. We hope that our study will motivate researchers to integrate the role of soil microbial communities in bioassays in allelopathic research so that its importance in plant-plant competitive interactions can be thoroughly evaluated.

  20. The future of Arctic benthos: Expansion, invasion, and biodiversity (United States)

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


    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

  1. 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 (United States)

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


    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

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

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


    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.

  3. The diversity and distribution of fungi on residential surfaces.

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    Rachel I Adams

    Full Text Available The predominant hypothesis regarding the composition of microbial assemblages in indoor environments is that fungal assemblages are structured by outdoor air with a moderate contribution by surface growth, whereas indoor bacterial assemblages represent a mixture of bacteria entered from outdoor air, shed by building inhabitants, and grown on surfaces. To test the fungal aspect of this hypothesis, we sampled fungi from three surface types likely to support growth and therefore possible contributors of fungi to indoor air: drains in kitchens and bathrooms, sills beneath condensation-prone windows, and skin of human inhabitants. Sampling was done in replicated units of a university-housing complex without reported mold problems, and sequences were analyzed using both QIIME and the new UPARSE approach to OTU-binning, to the same result. Surfaces demonstrated a mycological profile similar to that of outdoor air from the same locality, and assemblages clustered by surface type. "Weedy" genera typical of indoor air, such as Cladosporium and Cryptococcus, were abundant on sills, as were a diverse set of fungi of likely outdoor origin. Drains supported more depauperate assemblages than the other surfaces and contained thermotolerant genera such as Exophiala, Candida, and Fusarium. Most surprising was the composition detected on residents' foreheads. In addition to harboring Malassezia, a known human commensal, skin also possessed a surprising richness of non-resident fungi, including plant pathogens such as ergot (Claviceps purperea. Overall, fungal richness across indoor surfaces was high, but based on known autecologies, most of these fungi were unlikely to be growing on surfaces. We conclude that while some endogenous fungal growth on typical household surfaces does occur, particularly on drains and skin, all residential surfaces appear - to varying degrees - to be passive collectors of airborne fungi of putative outdoor origin, a view of the origins

  4. Occurrence and dynamics of Impatiens parviflora depending on various environmental conditions in the protected areas in Slovakia

    Directory of Open Access Journals (Sweden)

    Bobuľská Lenka


    Full Text Available Biological invasion as one of the main threats to natural ecosystems has big economic impact on conservation of nature. Studies of the population biology of invasive species may allow more precise focus on specific plant and soil characteristics involved in invasiveness. The aim of the study was to investigate the relationship between selected biological population characteristics of Impatiens parviflora and a few chosen chemical and physical soil features. Sites were selected because of the poor mapping of invasive plants in the protected natural areas and their interactions with specific soil characteristics. Research on I. parviflora was realised during a vegetation season in three forest nature reserves in Prešov district, Slovakia. Some population biological characteristics of I. parviflora as one of the most invasive plant species in Slovakia and Central Europe were surveyed. The correlation between the numbers of plants was analysed, as well as select population biological characteristics of I. parviflora (plant height, width of the largest leaf and the number of flowers/fruits on some select chemical and physical soil attributes (soil pH, bulk density, porosity and soil moisture were analysed. The results suggest that biological characteristics of I. parviflora in three different microhabitats – a meadow (a habitat without tree vegetation, a habitat close to the stumps and a habitat under dense tree vegetation seemed to influence the selected soil parameters. Our results showed that I. parviflora prefers acidic and non-compacted soil conditions. Sunlight and soil moisture do not show statistically significant differences on any biological characteristic of the population. The results also suggest that the autecology of I. parviflora in Western and Central Europe is not very well known and deserves further study.


    Reavie, Euan D; Kireta, Amy R; Kingston, John C; Sgro, Gerald V; Danz, Nicholas P; Axler, Richard P; Hollenhorst, Thomas P


    Because diatom communities are subject to the prevailing water quality in the Great Lakes coastal environment, diatom-based indices can be used to support coastal-monitoring programs and paleoecological studies. Diatom samples were collected from Great Lakes coastal wetlands, embayments, and high-energy sites (155 sites), and assemblages were characterized to the species level. We defined 42 metrics on the basis of autecological and functional properties of species assemblages, including species diversity, motile species, planktonic species, proportion dominant taxon, taxonomic metrics (e.g., proportion Stephanodiscoid taxa), and diatom-inferred (DI) water quality (e.g., DI chloride [Cl]). Redundant metrics were eliminated, and a diatom-based multimetric index (MMDI) to infer coastline disturbance was developed. Anthropogenic stresses in adjacent coastal watersheds were characterized using geographic information system (GIS) data related to agricultural and urban land cover and atmospheric deposition. Fourteen independent diatom metrics had significant regressions with watershed stressor data; these metrics were selected for inclusion in the MMDI. The final MMDI was developed as the weighted sum of the selected metric scores with weights based on a metric's ability to reflect anthropogenic stressors in the adjacent watersheds. Despite careful development of the multimetric approach, verification using a test set of sites indicated that the MMDI was not able to predict watershed stressors better than some of the component metrics. From this investigation, it was determined that simpler, more traditional diatom-based metrics (e.g., DI Cl, proportion Cl-tolerant species, and DI total phosphorus [TP]) provide superior prediction of overall stressor influence at coastal locales.

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

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


    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.


    Directory of Open Access Journals (Sweden)



    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.

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

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


    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 lake at about 6250 cal yr BP was related to sea level rise and resulting intrusion of seawater-influenced groundwater. In contrast, Gorgo Basso remained a freshwater lake. The salinity of Gorgo Basso declined somewhat after 6250 cal yr BP, in comparison to the early Holocene, ranging from about 550 to 1680 mg/L. Cypria ophtalmica, a 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Drake, S.J.


    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.

  10. Colonization ability of luxAB gene-marked Pseudomonas fluorescens CP1108 in cotton rhizosphere%发光酶基因(luxAB)标记的荧光假单胞菌CP1108的定殖能力研究

    Institute of Scientific and Technical Information of China (English)

    魏永涛; 唐欣昀


    By the method of tri-parent conjugation, the lux AB gene was introduced into P. Fluorescent CP1108. This study aimed at the autecology of P. Fluorescent CP1108 L and its colonization ability in cotton rhizosphere. The results showed that the marker gene luxAB was successfully transferred into strain CPU 08, and the plasmid with luxAB did not lose after 20 generations. Plasmid transformed had little effect on the growth and physiological and biochemical character of strain CPU 08 L. Strain CPU 08 L successfully colonized in the rhizoephere of cotton. The total population reached to the highest level 2. 31 x 105 cfu · G-1 and 3. 18 x 105 cfu · G-1 after 14 days, and the population reached to 9. 08 x 104 cfu · G-1 and 1.44 x 105 cfu · G-1at the root segment of 0 -2 cm. Pot experiment results showed that strain CP1108L had a good advance on the plant height, root length and dry weight of cotton.%利用三亲本杂交方法,将luxAB发光酶基因标记至荧光假单胞菌(Pseudomonas fluorescens)CP1108上,研究标记菌株CP1108L的个体生态学特征及其在棉花根圈的定殖动态.结果表明,标记菌株连续传代20次均未发生质粒丢失现象,标记质粒在受体菌株中较为稳定,CP1108L菌株的生长及部分生理生化特性没有受到标记质粒的影响;标记菌株能够在棉花根圈中成功定殖,棉花生长14 d时,CP1108L在所有深度的根段均达到最高定殖水平,定殖密度分别为2.31×105 cfu·g-1根土、3.18×105 cfu·g-1鲜根,而其中以0 ~~2 cm根段处标记菌株的定殖密度最大,根际和根表的菌数分别为9.08×104 cfu·g-1根土、1.44×105 cfu·g-1鲜根;接种CP1108和CP1108L菌液处理棉花植株的干重、主根长和株高显著高于对照组;两个菌株处理之间差异不显著.

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

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


    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.

  12. Characterizing adaptive morphological patterns related to diet in Bovidae (Mammalia: Artiodactyla)%牛科(哺乳纲:偶蹄目)动物与食物有关的适应形态模式

    Institute of Scientific and Technical Information of China (English)



    Morphological patterns in the craniodental structure of extant bovids indicative of ecological adaptations for feeding behavior were identified by stepwise discriminant analysis (SCDA). The analyses were carried out using 28 craniodental measurements from 72 extant bovid species. The discriminant functions obtained allow the characterization of six different types of dietary adaptations: general grazers, fresh-grass grazers, mixed-feeders from open habitat, browsers,mixed-feeders from closed habitat, and frugivores. The predictive ability of the algorithms was tested with 1 063 specimens, most of them lacking one or more measurements. The mean predictive ability of the discriminant functions over these specimens (94 % ) is only slightly lower than over the species used to obtain them (98 % ). Given that the algorithms involve small sets of craniodental measurements, they can also be applied to non-complete specimens from archaeological assemblages. These algorithms, combined with those obtained using postcranial measurements for estimating adaptations related to locomotor performance and habitat choice, are useful for deriving inferences on the autecology of ancient bovids and may be used in paleoenvironmental reconstruction [Acta Zoologica Sinica 52 (6): 988- 1008, 2006].%利用逐步分辨分析方法(Stepwise discriminant analysis,SCDA)检测了广义牛科动物的颅齿部结构,这些结构特征可以作为采食行为生态适应特征.在本研究中,测量了72种广义牛科动物的28个颅齿部结构.逐步分辨分析方法得出了6种采食方式适应类型:一般粗食者、新鲜禾草粗食者、开阔生境混合型采食者、精食者、郁闭生境混合型采食者、食果者.用103个标本检测了分辨指标的预测能力,所用标本为缺损标本,大多数缺少一项或多项结构.从这些标本获得的分辨函数的平均预测能力为94%,比用72种广义牛科动物标本建立的分辨函数的平均预测能力(98%)低

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

    Lukeneder, A.; Mayrhofer, S.


    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

  14. The early to mid-Miocene environment of Antarctica (United States)

    Ashworth, A. C.; Lewis, A.


    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. 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


    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

  16. 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


    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