WorldWideScience

Sample records for autecology

  1. Comparative autecological characteristics of northwestern tree species—a literature review.

    Science.gov (United States)

    Don. Minore

    1979-01-01

    This report is a compilation of autecological information previously scattered about in several hundred publications. It includes a comparison of the tolerances, traits, and attributes of native northwestern tree species. The species are ranked with respect to 69 environmental factors, phenotypic characteristics, and physical parameters. These rankings, with the...

  2. Are antioxidant capacity and oxidative damage related to biological and autecological characteristics in aquatic insects?

    Directory of Open Access Journals (Sweden)

    Ana Sanz

    2016-11-01

    Full Text Available In this work, we study the oxidative state of nine taxa of aquatic insects [Serratella ignita (Poda, 1761, Ephemera danica Müller, 1764, Crocothemis erythraea (Brullé, 1832, Dinocras cephalotes (Curtis, 1827, Perla bipunctata Pictet, 1833, Isoperla morenica Tierno de Figueroa & Luzón-Ortega, 2011, Notonecta maculata Fabricius, 1794, Gerris sp., and Hydropsyche sp.] in order to determine the relationships between this state and the biological and environmental characteristics of the species studied. The studied taxa are all in the same life cycle stage (nymph/larva, and many of them have different maximum life span potentials. We assess the antioxidant capacity through the determination of the trolox-equivalent antioxidant capacity, the ferric-reducing/antioxidant power and the activity of the antioxidant enzymes catalase, DT-diaphorase, glutathione peroxidase, glutathione reductase, glutathione transferase, superoxide dismutase and glucose-6-phosphate dehydrogenase. Furthermore, to determine the oxidative damage, we examine thiobarbituric acid reactive substances, free malondialdehyde, protein-bound malondialdehyde, total hydroperoxides, and protein hydroperoxides. In summary, we can consider that having predatory feeding habits, having a long-life cycle and living in permanent streams with cold, well-oxygenated waters are related to a proper oxidative state in the insects that we studied. On the other hand, non-exclusive predator species living in temporary streams with warm and poorly oxygenated waters with a short life cycle have a worse oxidative state. Thus, the oxidative state of each species could be defined by an interaction of biological and autecological factors, for which the relative importance is difficult to assess.

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

    Directory of Open Access Journals (Sweden)

    Rico, E.

    1998-12-01

    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.

  4. Preliminary Assessment on Autecological Studies of Beardless Barb, Cyclocheilichthys apogon (Valenciennes, 1842) from Muda Reservoir of Kedah, Malaysia.

    Science.gov (United States)

    Rosli, Nor Aziella Mohd; Zain, Khaironizam Md

    2016-11-01

    Like many other countries, reservoirs in Malaysia are primarily built for various functions such as hydroelectric power generation, drinking water supply, flood mitigation and irrigation for agricultural purposes. Artisanal fisheries activities were also performed in these reservoirs. The freshwater fish are a requisite source of protein for the rural population. Consequently, the fish resources in reservoirs should be carefully maintained at sustainable level. Present study elucidates the preliminary assessment on autecological studies of beardless barb, Cyclocheilichthys apogon as a model of fish biota in Muda Reservoir. This research investigates the growth pattern of C. apogon using length-weight relationship and their condition factor. A total of 307 specimens were captured using cast net for six consecutive months from March 2014 until August 2014. The growth coefficient (b) from the length-weight equation (W = aL b ) for male and female of C. apogon were 3.150 and 3.185, respectively, indicating positive allometric growth. The condition factor values of male and female of C. apogon were 1.023 ± 0.111 and 1.026 ± 0.100, respectively, suggesting that C. apogon is in good condition in Muda Reservoir. The paucity of research on the autecological study in the Muda Reservoir contributes to the main reason of performing this research. The findings will serve as baseline information of this species in Muda Reservoir, as well as for comparative study in the future.

  5. The use of autecological and environmental parameters for establishing the status of lichen vegetation in a baseline study for a long-term monitoring survey

    International Nuclear Information System (INIS)

    Gombert, S.; Asta, J.; Seaward, M.R.D.

    2005-01-01

    In 1997 the ecological characteristics of the epiphytic species (83 lichens and two algae) of an urban area (Grenoble, France) were determined. Seven autecological indices were used to characterize the lichen ecology: illumination index, humidity index, pH of bark, nutrient status of substratum, ecological index of IAP and frequency. Six clusters (A1-A6) were defined using cluster analysis and principal component analysis. Seven environmental parameters characterizing the stations and the lichen releves were also used: elevation, parameters of artificiality (urbanization, traffic and local land use), IAP, and the percentage of nitrophytic and acidophytic species. Six clusters (B1-B6) were defined using cluster analysis and canonical correspondence analysis. Four clusters (C1-C4) were finally defined using an empirical integrated method combining the autecological and environmental parameters. This final clustering which established the status of the lichen vegetation in 1997 can be reliably used as a baseline study to effectively monitor environmental changes in this urban area. - Ecological clustering which establishes the status of lichen vegetation can be reliably used as a baseline study to monitor environmental changes

  6. The use of autecological and environmental parameters for establishing the status of lichen vegetation in a baseline study for a long-term monitoring survey

    Energy Technology Data Exchange (ETDEWEB)

    Gombert, S. [Museum National d' Histoire Naturelle, Departement RDDM, USM 505 Case 39, 57 rue Cuvier, 75005 Paris (France)]. E-mail: sgombert@mnhn.fr; Asta, J. [Laboratoire d' Ecologie Alpine, UMR 5553, Equipe Perturbations Environnementales et Xenobiotiques, Universite Joseph Fourier, 38041 Grenoble cedex 9 (France)]. E-mail: juliette.asta@ujf-grenoble.fr; Seaward, M.R.D. [Department of Environmental Science, University of Bradford, Bradford BD7 1DP (United Kingdom)]. E-mail: m.r.d.seaward@bradford.ac.uk

    2005-06-15

    In 1997 the ecological characteristics of the epiphytic species (83 lichens and two algae) of an urban area (Grenoble, France) were determined. Seven autecological indices were used to characterize the lichen ecology: illumination index, humidity index, pH of bark, nutrient status of substratum, ecological index of IAP and frequency. Six clusters (A1-A6) were defined using cluster analysis and principal component analysis. Seven environmental parameters characterizing the stations and the lichen releves were also used: elevation, parameters of artificiality (urbanization, traffic and local land use), IAP, and the percentage of nitrophytic and acidophytic species. Six clusters (B1-B6) were defined using cluster analysis and canonical correspondence analysis. Four clusters (C1-C4) were finally defined using an empirical integrated method combining the autecological and environmental parameters. This final clustering which established the status of the lichen vegetation in 1997 can be reliably used as a baseline study to effectively monitor environmental changes in this urban area. - Ecological clustering which establishes the status of lichen vegetation can be reliably used as a baseline study to monitor environmental changes.

  7. 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

  8. Oscillatoria simplicissima : an autecological study | Venter | Water SA

    African Journals Online (AJOL)

    Although this blue-green alga is presumably non-toxic, a study over a seven-year period shows that it is one of the most important bloom-forming blue-green algal species in the Vaal River, interfering with recreational activities as well as water purification. During this study, environmental variables influencing the ...

  9. Some Aspects Of The Autecology Of Panicum Turgidum Forsk

    OpenAIRE

    Ismail, A. M. A. [احمد محمد علي اسماعيل; El Seed, M. T.

    1983-01-01

    The germination of Panicum turgidum seeds was tested under different conditions. They showed ability to germinate under a range of temperatures from 25-42°C. The maximum percentage of germination was 45%, at 30°C. The species responded differently to the various chemical substances used to stimulate its germination. The particular effect of each chemical substance was discussed. The percentage of seedling emergence was highest in the case of seeds sown at 0. cm depth and decreased gradually a...

  10. Autecology of Scleroconidioma sphagnicola particularly in Šumava National Park (Czech Republic)

    Czech Academy of Sciences Publication Activity Database

    Koukol, Ondřej; Kovářová, Marcela

    2007-01-01

    Roč. 59, č. 1 (2007), s. 111-123 ISSN 1211-0981 R&D Projects: GA ČR GA206/05/0269; GA ČR(CZ) GD206/03/H137 Institutional research plan: CEZ:AV0Z60050516 Keywords : microsclerotia * coniferous litter * Sphagnum Subject RIV: EF - Botanics

  11. PHYLOGENETIC ANALYSIS AND AUTECOLOGY OF SPORE-FORMING BACTERIA FROM HYPERSALINE ENVIRONMENTS.

    Science.gov (United States)

    Gladka, G V; Romanovskaya, V A; Tashyreva, H O; Tashyrev, O B

    2015-01-01

    Multi-resistant to extreme factors spore-forming bacteria of Bacillus genus are isolated from hypersaline environments of the Crimea (Ukraine) and the Dead Sea (Israel). Phylogenetic analysis showed distinction of dominating extremophilic culturable species in studied regions. In Crimean environments they are B. mojavensis and B. simplex, in the Dead Sea ecosystem--B. subtilis subsp. spizizenii, B. subtilis subsp. subtilis, B. licheniformis and B. simplex. Isolates are simultaneously halotolerant and resistant to UV radiation. Strains isolated from the Dead Sea and the Crimea environments were resistant to UV: LD90 and LD99.99 made 100-170 J/m2 and 750-1500 J/m2 respectively. Spores showed higher UV-resistance (LD99.99-2500 J/m2) than the vegetative cells. However the number of spores made 0.02-0.007% of the whole cell population, and should not significantly affect the UV LD99.99 value. Isolates of both environments were halotolerant in the range of 0.1-10% NaCl and thermotolerant in the range of 20-50 °C, and didn't grow at 15 °C. Survival strategy of spore-forming bacteria from hypersaline environments under high UV radiation level can be performed by spore formation which minimize cell damage as well as efficient DNA-repair systems that remove damages.

  12. Xanthophyceaen assemblages during winter - spring flood: autecology and ecophysiology of Tribonema fonticolum and T. monochloron

    Czech Academy of Sciences Publication Activity Database

    Machová, K.; Elster, Josef; Adamec, Lubomír

    2008-01-01

    Roč. 600, č. 1 (2008), s. 155-168 ISSN 0018-8158 R&D Projects: GA ČR GA526/00/1442; GA MŠk ME 576 Grant - others:EU(XE) QLRT-2000-01645(COBRA) Institutional research plan: CEZ:AV0Z60050516 Keywords : Tribonema, growth conditions, temperature * temperature, inorganic carbon * desiccation, freezing Subject RIV: EF - Botanics Impact factor: 1.449, year: 2008

  13. An Autecological Study on the Vitex agnus-castus L. (Verbenaceae) Distributed in West Anatolia

    OpenAIRE

    DOĞAN, Yunus; MERT, Hasan Hüseyin

    2014-01-01

    This study covers the investigation of the soil-plant relations of Vitex agnus-castus L. (Verbenaceae), a typical element of Mediteranean macchia vegetation. Soils collected from 38 different localitis in West Anatolia were analysed together with the V. agnus-castus plants from the same localities. This plant was observed to generally prefer loamy-textured, neutral and slightly alka-line soils, poor in calcium carbonate, containing varying amounts of organic matter, being rich or very rich...

  14. 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)

  15. Autecology of the common mormon butterfly, Papilio polytes (Lepidoptera : Rhopalocera : Papilionidae).

    Science.gov (United States)

    Atluri, J B; Ramana, S P Venkata; Reddi, C Subba

    2002-04-01

    The adults of the common mormon butterfly Papilio polytes Linn. feed on a variety of floral species. The larval food plants in the study area included Citrus limon and Murraya koenigii both of the family Rutaceae. The eggs are laid singly, and the hatching time is three days. The larvae pass through five instars. The larval growth is directly correlated with the quantity of food consumed. The AD (approximate digestibility) values decreased from first instar to the last, whereas the ECD (efficiency of conversion of digested food) and ECI (efficiency of conversion of ingested food) values increased, thus bearing an inverse relationship with AD. The development time from egg to adult is 28-30, giving 11-12 generations in a year, but with better breeding during August-February. Thus P. polytes is multivoltine.

  16. Autecology of the tailed jay butterfly Graphium agamemnon (Lepidoptera : Rhopalocera : Papilionidae).

    Science.gov (United States)

    Ramana, S P Venkata; Atluri, J B; Reddi, C Subba

    2003-07-01

    The Tailed Jay Graphium agamemnon is one of the attractive papilionid butterflies that enliven the environment of Visakhapatnam. It occurs throughout the year. It lays eggs singly on young leaves of the mast tree Polyalthia longifolia var. pendula (Annonaceae). The eggs take 3-4 days to hatch. The larvae go through 5 instars over a period of 15-16 days. The pupal period is 13-14 days. The total period from egg to adult emergence spans over 33-36 days. Based on this short life cycle, and larval and pupal development success studied every month, this butterfly can be multivoltine with a minimum of 7-8 broods in a year. Both CI and GR decreased with the age of larva, their average figures being 3.78 and 0.43 respectively. AD values are high (average 92%) and decreased through successive instars. Both ECD and ECI followed a similar pattern with an increase from instar I up to II, then a decrease up to IV and again an increase in instar V and the highest value is with fifth instar. Adults frequently visited flowers (12-35 flowers in a min) spending 1.0 to 3.2 seconds on a flower. The nectar concentration ranged between 16 and 58%. Peak foraging activity mostly fell between 0900-1000 h. The proboscis received pollen in most of the floral species visited, thus satisfying one of the characteristics of butterfly pollination. Being a fast and strong flier it is treated as "high energy" pollinator promoting cross-pollination.

  17. Charophytes (Characeae, Charophyta) in the Czech Republic: taxonomy, autecology and distribution

    Czech Academy of Sciences Publication Activity Database

    Caisová, Lenka; Gabka, M.

    2009-01-01

    Roč. 9, č. 1 (2009), s. 1-43 ISSN 1802-5439 R&D Projects: GA ČR GA206/09/0697 Institutional research plan: CEZ:AV0Z60050516 Keywords : Charophytes * distribution * taxonomy Subject RIV: EF - Botanics Impact factor: 1.762, year: 2009

  18. The autecology of small rodents and insectivores of the Tribeč Mountain range

    Science.gov (United States)

    Grulich, I.; Nosek, J.; Szabó, L.

    1967-01-01

    Small rodents and insectivores have become the main reservoirs of tick-borne encephalitis virus. In order, therefore, to demonstrate the dynamic and structural changes occurring in a natural focus of tick-borne encephalitis, information has been collected on the distribution, habitat, life-cycle, population density and extent of tick infestation of the rodents and insectivores that inhabit the Tribeč region and adjacent parts of the Hronský Inovec Mountains. The following mammals are discussed: Sciurus vulgaris, Citellus citellus, Glis glis, Muscardinus avellanarius, Mus musculus, Micromys minutus, Apodemus flavicollis, A. sylvaticus, Microtus arvalis, Pitymys subterraneus, Clethrionomys glareolus, Arvicola terrestris, Sorex araneus, S. minutus, Neomys fodiens, N. anomalus, Crocidura suaveolens, C. leucodon, Erinaceus roumanicus and Talpa europaea. Many of these are important reservoirs of virus. PMID:5298539

  19. Comparative study of autecological, morphological, anatomical and karyological characteristics of Acanthophyllum ejtehadii Mahmoudi & Vaezi (Caryophyllaceae: a rare endemic in Iran

    Directory of Open Access Journals (Sweden)

    Zahra Maleki Sadabadi

    2017-08-01

    Full Text Available Characterizing traits of a species in its habitat is substantial for planning a practical conservation program. Acanthophyllum ejtehadii Mahmoudi & Vaezi (Caryophyllaceae is a recently established endemic species for flora of Iran and has a narrow non-conserved natural habitat in Radkan region of Chenaran, Razavi Khorasan Province. The soil and climate of Radkan was studied and the ecological, morphological, anatomical, and karyological aspects of A. ejtehadii were investigated to obtain a comprehensive knowledge about this species and its natural growth conditions. Field observations were performed during the growing seasons in 2014‒2015 and 29 vegetation samples were collected as data. Results showed that this plant grows in mound-like sites on clay-loam soils at mean elevation 1279 m.a.s.l. in arid climate. Acanthophyllum ejtehadii is a thorn-cushion form chamaephyte plant. This Plant grow gradually in early-January, the flower unfolds in early-June and the matured seeds are produced in mid-July. A. ejtehadii is a diploid (2n=2x =30 species and has homogenous karyotype. Having unique morphological and anatomical adaptations such as expanded surface roots, reduced leaf area and thickened cuticle, this plant grows successfully in harsh environments. These mechanisms are specific to this specific kind of Acanthophyllum species. The Speciation time of this plant was estimated not more than 200 thousand years ago and if Radkan is preserved from anthropogenic disturbance, this species could expand its distribution area.

  20. 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.

  1. ASSESSMENT OF ISOLATED WETLAND CONDITION IN FLORIDA USING EPIPHYTIC DIATOMS AT GENUS, SPECIES, AND SUBSPECIES TAXONOMIC RESOLUTION

    Science.gov (United States)

    Diatoms are useful indicators of aquatic conditions, and metrics based on published autecological indicator values have been developed utilizing their sensitivities to various ambient physical and chemical conditions. The autecological values often differ within genera, and indee...

  2. 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.

  3. Temperature and oxygen requirements of early life stages of the endangered spined loach, Cobitis taenia L.(teleostei, Cobitidae) with implications for the management of natural populations

    Czech Academy of Sciences Publication Activity Database

    Bohlen, Jörg

    2003-01-01

    Roč. 157, č. 2 (2003), s. 195-212 ISSN 0003-9136 Institutional research plan: CEZ:AV0Z5045916 Keywords : autecology * physiological adaptation * microhabitat Subject RIV: ED - Physiology Impact factor: 1.261, year: 2003

  4. Source pool geometry and the assembly of continental avifaunas

    DEFF Research Database (Denmark)

    Graves, Gary R; Rahbek, Carsten

    2005-01-01

    Classical niche-assembly models propose that the composition of biotic communities in continental landscapes is determined chiefly by the autecology of species, interspecific competition, and the diversity of resources and habitats within a region. In contrast, stochastic models propose that simu...

  5. Isolation and cultivation of planktonic freshwater microbes is essential for a comprehensive understanding of their ecology.

    Czech Academy of Sciences Publication Activity Database

    Salcher, Michaela M.; Šimek, Karel

    2016-01-01

    Roč. 77, č. 3 (2016), s. 183-196 ISSN 0948-3055 R&D Projects: GA ČR(CZ) GA13-00243S Institutional support: RVO:60077344 Keywords : autecology * axenic cultures * dilution to extinction * ecophysiology * genomics * isolation of freshwater microbes * targeted enrichment Subject RIV: EE - Microbiology, Virology Impact factor: 1.633, year: 2016

  6. Further contribution to the diatom flora of sewage enriched waters in southern Africa

    CSIR Research Space (South Africa)

    Schoeman, FR

    1972-01-01

    Full Text Available The systematics and autecology of the diatoms observed in an algal sample from a maturation pond of the Walvis Bay (south west African coast) sewage works are discussed. Fourteen diatoms species are recorded. A new specie, Amphora subacutiuscula...

  7. Wildland fire in ecosystems: effects of fire on flora

    Science.gov (United States)

    James K. Brown; Jane Kapler Smith

    2000-01-01

    VOLUME 2: This state-of-knowledge review about the effects of fire on flora and fuels can assist land managers with ecosystem and fire management planning and in their efforts to inform others about the ecological role of fire. Chapter topics include fire regime classification, autecological effects of fire, fire regime characteristics and postfire plant community...

  8. Habitat use of age 0 Alabama shad in the Pascagoula River drainage, USA

    Science.gov (United States)

    P. F. Mickle; J.F. Schaefer; S.B. Adams; B.R. Kreiser

    2010-01-01

    Alabama shad (Alosa alabamae) is an anadromous species that spawns in Gulf of Mexico drainages and is a NOAA Fisheries Species of Concern. Habitat degradation and barriers to migration are considered contributing factors to range contraction that has left just the Pascagoula River drainage population in Mississippi. We studied juvenile life history and autecology in...

  9. PRODUCTION ECOLOGY OF THE NON-INDIGENOUS SEAGRASS, DWARF EELGRASS (ZOSTERA JAPONICA ASCHER. & GRAEB.), IN A PACIFIC NORTHWEST ESTUARY, USA

    Science.gov (United States)

    The non-indigenous seagrass Zostera japonica Ascher. & Graeb. (dwarf eelgrass) was first identified in central Oregon (USA) estuaries about 30 years ago. The autecology of this species is poorly described at the southern end of its non-native range although several process orien...

  10. Effects of climate change on wildlife in the Northern Rockies [Chapter 8

    Science.gov (United States)

    Kevin S. McKelvey; Polly C. Buotte

    2018-01-01

    Few data exist on the direct effects of climatic variability and change on animal species. Therefore, projected climate change effects must be inferred from what is known about habitat characteristics and the autecology of each species. Habitat for mammals, including predators (Canada lynx, fisher, wolverine) and prey (snowshoe hare) that depend on high-elevation,...

  11. Polyphasic characterization of Westiellopsis prolifica (Hapalosiphonaceae, Cyanobacteria) from the El-Farafra Oasis (Western Desert, Egypt)

    Czech Academy of Sciences Publication Activity Database

    Saber, A. A.; Cantonati, M.; Mareš, Jan; Anesi, A.; Guella, G.

    2017-01-01

    Roč. 56, č. 6 (2017), s. 697-709 ISSN 0031-8884 Institutional support: RVO:60077344 Keywords : 16S rRNA * autecology * bio-organic screening * Egypt * polyphasic study Subject RIV: EF - Botanics OBOR OECD: Plant sciences, botany Impact factor: 1.826, year: 2016

  12. Tools for assessing European streams with macroinvertebrates: major results and conclusions from the STAR project

    NARCIS (Netherlands)

    Verdonschot, P.F.M.; Moog, O.

    2006-01-01

    This short paper summarises the information developed in the EU funded research project STAR on autecology databases, metrics, multimetrics and community approaches. For Europe the WFD implementation gave an important stimulus for the development of ecology based assessment techniques. Along with

  13. 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 c...

  14. Spawning marks in spined loaches (Cobitis taenia; Cobitidae; Teleostei)

    Czech Academy of Sciences Publication Activity Database

    Bohlen, Jörg

    2008-01-01

    Roč. 57, 1-2 (2008), s. 168-171 ISSN 0139-7893. [International Conference Loaches of the genus Cobitis and related genera. Šibenik, 24.09.2006-29.09.2006] R&D Projects: GA ČR GA206/05/2556; GA AV ČR IAA600450508 Institutional research plan: CEZ:AV0Z50450515 Keywords : freshwater fish * reproduction * autecology Subject RIV: EG - Zoology Impact factor: 0.522, year: 2008

  15. 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.

    2015-01-01

    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 three environmentally relevant heterotrophic bacteria isolated from Baltic Sea surface water: Pseudomonas...... between nitrogenase reductase gene expression and ethylene (C2H4) production indicated tight posttranscriptional-level control. The N2 fixation rates obtained suggested that, given the right conditions, these heterotrophic diazotrophs could contribute significantly to in situ rates. IMP...

  16. The Ecological Profiles Technique applied to data from Lichtenburg, South Africa

    Directory of Open Access Journals (Sweden)

    J. W. Morris

    1974-12-01

    Full Text Available The method of ecological profiles and information shared between species and ecological variables, developed in France, is described for the first time in English. Preliminary results, using the technique on Bankenveld quadrat data from Lichtenburg, Western Transvaal, are given. It is concluded that the method has great potential value for the understanding of the autecology of South African species provided that the sampling method is appropriate.

  17. STUDIES ON THYSANURA. UI. SOME FACTORS AFFECTING THE ...

    African Journals Online (AJOL)

    Thysanura has, as yet, bem undcrtakelJl.. The presmt i-nvesti.ption is, an attempt to' interpret the distrmution of these animaJs. in terms of the autecolOgy 01 MlltdtiJoirJes delanyi Wygod- zinsky ami CtetlO/episma 1mc~ta:lata E~herich. two specia; wI1aIc- WIIII:r CWCGIIImIJ' and. oriaLtations to thei.r physical environment ...

  18. Comparison of similar Arctic and Antarctic morphotypes of heterotrophic protists regarding their genotypes and ecotypes.

    Science.gov (United States)

    Nitsche, Frank; Arndt, Hartmut

    2015-02-01

    The polar regions offer the opportunity to study possible diversification processes of spatially and temporally separated populations. We focused our study on similar morphotypes/species (e. g. species with the same morphology) of heterotrophic flagellates and ciliates originating from both, Antarctic and Arctic waters: 38 populations of six choanoflagellate morphospecies (Acanthocorbis unguiculata, Helgoeca nana, Diaphanoeca grandis, Savillea micropora, Stephanoeca apheles, Salpingoeca tuba), four other flagellate morphospecies (Cafeteria roenbergensis, Podomonas magma, Procryptobia sorokini, Protaspis sp.) and three ciliate morphospecies (Holosticha sp., Uronema marinum, Pseudocohnilembus persalinus). We analysed similarities and differences regarding their genotypes (SSU rDNA) and for several species regarding morphotypes and autecology (temperature and salinity tolerance). Most of the investigated polar protists were psychrophilic and showed a high salinity tolerance. Morphologically well defined acanthoecid choanoflagellates isolated from both poles showed the lowest intraspecific diversity (< 0.5% p-distance). No intragenomic polymorphism of SSU rDNA within one individual and among clones from one population occurred. The way of dispersal for acanthoecid choanoflagellates still remains unclear. Even under extreme stress none of the examined cultures formed cysts. Single cell PCR appeared to be an appropriate method to investigate species not available as monoclonal cultures. As a prerequisite for barcoding, acanthoecid choanoflagellate species have a very low intraspecific variability regarding SSU rDNA. There was a clear correlation between autecological, morphological and molecular data sets, which may help interpreting molecular data from clone libraries or next generation sequencing. Copyright © 2014 Elsevier GmbH. All rights reserved.

  19. Ecological profiles of caddisfly larvae in Mediterranean streams: implications for bioassessment methods

    International Nuclear Information System (INIS)

    Bonada, N.; Zamora-Munoz, C.; Rieradevall, M.; Prat, N.

    2004-01-01

    Caddisflies are a well represented group with high species diversity in Mediterranean climate rivers. Although they are widely used in water quality assessment, little is known of the ecological profiles of families or species. We present a simple score for ecological profiles which measures intolerance to water quality. The ecological profiles of caddisflies are diverse and the degree of tolerance at the family level is related to species diversity and the tolerance of individual species to water quality. Comparisons with the scores used in the biotic index IBMWP show general agreement between the degree of intolerance of a family and its score in the IBMWP, with few exceptions. Studies on tolerance are required to elucidate the autecology of taxa, and to develop biological indices, especially in areas with high species diversity. - Capsule: Ecological profiles of caddisfly larvae in Mediterranean streams using water quality variables

  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

    Directory of Open Access Journals (Sweden)

    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. Science.gov (United States)

    Remmert, Hermann

    1969-08-01

    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

    Directory of Open Access Journals (Sweden)

    A. Whateley

    1983-11-01

    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.

  4. Patch Size and Population Density: the Effect of Immigration Behavior

    Directory of Open Access Journals (Sweden)

    Jeff Bowman

    2002-06-01

    Full Text Available Many habitat fragmentation experiments make the prediction that animal population density will be positively related to fragment, or patch, size. The mechanism that is supposed to result in this prediction is unclear, but several recent reviews have demonstrated that population density often is negatively related to patch size. Immigration behavior is likely to have an important effect on population density for species that do not show strong edge effects, for species that have low emigration rates, and during short-term habitat fragmentation experiments. We consider the effect that different kinds of immigration behaviors will have on population density and we demonstrate that only a minority of possible scenarios produce positive density vs. patch size relationships. More commonly, these relationships are expected to be negative. Our results demonstrate the importance of considering autecological mechanisms, such as immigration behavior, when developing the predictions that we test in habitat fragmentation or other experiments.

  5. Food-web models predict species abundances in response to habitat change.

    Directory of Open Access Journals (Sweden)

    Nicholas J Gotelli

    2006-10-01

    Full Text Available Plant and animal population sizes inevitably change following habitat loss, but the mechanisms underlying these changes are poorly understood. We experimentally altered habitat volume and eliminated top trophic levels of the food web of invertebrates that inhabit rain-filled leaves of the carnivorous pitcher plant Sarracenia purpurea. Path models that incorporated food-web structure better predicted population sizes of food-web constituents than did simple keystone species models, models that included only autecological responses to habitat volume, or models including both food-web structure and habitat volume. These results provide the first experimental confirmation that trophic structure can determine species abundances in the face of habitat loss.

  6. 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.

    2015-01-01

    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 three environmentally relevant heterotrophic bacteria isolated from Baltic Sea surface water: Pseudomonas...... in length and complexity between isolates. All three isolates could sustain growth by N2 fixation in the absence of reactive N, and this fixation was stimulated by low concentrations of oxygen in all three organisms (≈4 to 40 μmol O2 liter-1). P. stutzeri BAL361 did, however, fix N at up to 165 μmol O2...... between nitrogenase reductase gene expression and ethylene (C2H4) production indicated tight posttranscriptional-level control. The N2 fixation rates obtained suggested that, given the right conditions, these heterotrophic diazotrophs could contribute significantly to in situ rates. IMP...

  7. Macroecological signals of species interactions in the Danish avifauna

    DEFF Research Database (Denmark)

    Gotelli, N.J.; Graves, Christopher R.; Rahbek, C.

    2010-01-01

    The role of intraspecific and interspecific interactions in structuring biotic communities at fine spatial scales is well documented, but the signature of species interactions at coarser spatial scales is unclear. We present evidence that species interactions may be a significant factor...... in mediating the regional assembly of the Danish avifauna. Because >95% of breeding species (n = 197) are migratory, we hypothesized that dispersal limitation would not be important and that breeding distributions would largely reflect resource availability and autecological habitat preferences. Instead, we...... detected a striking pattern of spatial segregation between ecologically similar species at two spatial scales with a suite of null models that factored in the spatial distribution of habitats in Denmark as well as population size and biomass of each species. Habitat utilization analyses indicated...

  8. Recent findings regarding non-native or poorly known diatom taxa in north-western Italian rivers

    Directory of Open Access Journals (Sweden)

    Elisa Falasco

    2013-02-01

    Full Text Available Diatoms of the major rivers of North-Western Italy were investigated to highlight the presence of species of particular ecological interest but not as yet recorded. The survey area included streams belonging to seven different hydroecoregions (HERs with a wide range of physical characteristics. Between 2008 and 2010, 200 samples were taken for the study of the diatom community composition, while a larger set of samples was examined to determine the presence or absence of the nuisance diatom species Didymosphenia geminata (Lyngbye Schmidt. A specific field study was performed in two rivers characterized by persistent blooms of this species to evaluate the effects of its proliferation on the benthic communities. D. geminata was present in almost 20% of the samples. From a comparison with published data, we can confirm that D. geminata has recently been expanding its ecological range, as it has been found also in mesotrophic lowlands water. In some instances the formation of massive proliferation has been recorded. The calculation of autecological values confirmed its preference for oligotrophic waters with low mineral content and organic loading, although with a wider ecological amplitude than recorded in the first studies on this species. Another four taxa of particular interest were detected: Achnanthidium subhudsonis (Hustedt Kobayasi (in 15 sites, Cymbella tropica Krammer (11 sites, Mayamaea cahabaensis Morales and Manoylov (2 sites and Reimeria uniseriata Sala, Guerrero and Ferrario (18 sites. The first three species must be considered new records for Northern Italy. A. subhudsonis and C. tropica reached up to 20% relative abundance. From the analysis of their distribution and autecological values, we can assert that A. subhudsonis and M. cahabaensis show a preference for high values of nitrogen, this latter preferring also quite high values of total phosphorus. C. tropica prefers intermediate values of nitrogen nutrients and R. uniseriata is

  9. Biofacies and habitats of Brereton Limestone member (Carbondale Formation, Middle Pennsylvanian), Southwestern Illinois

    Energy Technology Data Exchange (ETDEWEB)

    O' Connell, D.B.; Utgaard, J.

    1983-09-01

    The Brereton Limestone is a shallow-water, open-marine carbonate deposited over peat or delta-plain muds after delta abandonment and a marine transgression. Data on autecology, lithology, insoluble residue content, and thickness were used to interpret the habitats of each biofacies. Biofacies V, a low-diversity biofacies dominated by brachiopods and ostracods, occupied turbid-water, mud- or shelly mud-bottom areas during influxes of detrital clays late in the abandonment of the Herrin delta and, also, early in the construction of the Jamestown delta. Low-relief carbonate mud mounds accumulated within and around baffles provided by thickets of phylloid algae and foraminifers, are capped locally by biofacies VI, a low-diversity biofacies dominated by ostracods. Biofacies VI, occupied the high subtidal to supratidal crests of algal mud mounds which had a stressed (possibly hypersaline) environment. Deeper water mud mounds were occupied by either Biofacies III, a crinoid-mixed fossil biofacies, or by Biofacies IV, which is dominated by fusulinids, strophomenids, and trilobites. Biofacies II, dominated by sponges, mollusks, and impunctate brachiopods, generally occurred on the flanks of the shallow-water mounds. Biofacies I, III, and IV also occurred in broad, muddy intermound areas and Biofacies III in narrow, winnowed intermound areas.

  10. Macroecological signals of species interactions in the Danish avifauna.

    Science.gov (United States)

    Gotelli, Nicholas J; Graves, Gary R; Rahbek, Carsten

    2010-03-16

    The role of intraspecific and interspecific interactions in structuring biotic communities at fine spatial scales is well documented, but the signature of species interactions at coarser spatial scales is unclear. We present evidence that species interactions may be a significant factor in mediating the regional assembly of the Danish avifauna. Because >95% of breeding species (n = 197) are migratory, we hypothesized that dispersal limitation would not be important and that breeding distributions would largely reflect resource availability and autecological habitat preferences. Instead, we detected a striking pattern of spatial segregation between ecologically similar species at two spatial scales with a suite of null models that factored in the spatial distribution of habitats in Denmark as well as population size and biomass of each species. Habitat utilization analyses indicated that community-wide patterns of spatial segregation could not be attributed to the patchy distribution of habitat or to gross differences in habitat utilization among ecologically similar species. We hypothesize that, when habitat patch size is limited, conspecific attraction in concert with interspecific territoriality may result in spatially segregated distributions of ecologically similar species at larger spatial scales. In the Danish avifauna, the effects of species interactions on community assembly appear pervasive and can be discerned at grain sizes up to four orders of magnitude larger than those of individual territories. These results suggest that species interactions should be incorporated into species distribution modeling algorithms designed to predict species occupancy patterns based on environmental variables.

  11. Diversity and Distribution of Myrmecophytes in Bengkulu Province

    Directory of Open Access Journals (Sweden)

    Safniyeti Safniyeti

    2017-07-01

    Full Text Available Myrmecophyte is a common medicinal plant used by local people in Indonesia for treating various diseases especially in Papua. Bengkulu province is one of the Myrmecophyte habitats, but there has no report on its identity and distribution. The objectives of this research were to identify the diversity and analyze the Myrmecophytes distribution as well as factor affecting its presence. This study used purposive sampling method by exploring the area where Myrmecophytes commonly found. The Myrmecophyte distribution based on host tree was analyzed using Morishita index and the autecological analysis of abiotic factors was performed using Principal Component Analysis (PCA generated from Minitab 16. The results of this research showed that there were two species of Myrmecophytes in Bengkulu province, namely Hydnophytum formicarum and Myrmecodia tuberosa, as well as two variants of M. tuberosa i.e. M. tuberosa ‘armata’ and M. tuberosa ‘siberutensis’. The distribution of Myrmecophytes based on host tree was mostly randomly scattered in Central Bengkulu regency, Seluma, North Bengkulu, South Bengkulu, and Kaur. Their distributions were affected by light intensity and temperature. The data of this research can be used as basic information for carried out conservation efforts in Bengkulu province. The abundance of Myrmecophytes is also used as a source of additional income for local people in Bengkulu province.     

  12. Eco-distribution Mapping of Invasive Weed Limnocharis flava (L. Buchenau Using Geographical Information System: Implications for Containment and Integrated Weed Management for Ecosystem Conservation

    Directory of Open Access Journals (Sweden)

    P. C. Abhilash

    2008-03-01

    Full Text Available Exotic weed invasion has been identified as one of the serious environmental problem impacting the structure, composition and function of biological diversity. They are aggressive colonizers, which have flexible habitat requirement and ability to outcompete native species. The present paper describes the distribution and autecology of an exotic weed Limnocharis flava (L. Buchenau (an emergent aquatic weed of ‘Limnocharitaceae’ in Kumarakom Grama Panchayat, one of the well known tourist spot of South India famous for its vast stretches of paddy fields, wetlands and backwaters. The mapping of L. flava in the entire study area has been done using Geographical Information System (Arc-info 8.3 version. The growth and distribution pattern of L. flava were studied quantitatively. Data on distribution, abundance, biomass, ecological associations and root zone nutrient quality of water and sediment samples were collected from different sampling points of Kumarakom. The study reflected that nutrients, water depth and land use patterns were the major factors responsible for the growth and proliferation of this exotic weed. The strategies for controlling L. flava invasion are discussed in detail. If early steps are not taken to eradicate this weed, it will become a problematic weed in the same way as other noxious aquatic weeds like Salvinia molesta D. Mitch and Eichhornia crassipes (C. Martius Solms-Laub.

  13. Evaluating the Intraspecific Interactions of Indian Rosewood (Dalbergia sissoo Roxb. Trees in Indian Rosewood Reserveof Khuzestan Province

    Directory of Open Access Journals (Sweden)

    Y. Erfanifard

    2016-05-01

    Full Text Available Positive and negative (facilitative and competitive interactions of plants are important issues in autecology and can be evaluated by the spatial pattern analysis in plant ecosystems. This study investigates the intraspecific interactions of Indian rosewood (Dalbergia sissoo Roxb. trees in Indian rosewood Reserve of Khuzestan province. Three 150 m × 200 m plots were selected and the spatial locations of all Indian rosewoods (239 trees were specified. Structurally different summary statistics (nearest neighbour distribution function D(r, K2-index K2(r, pair correlation function g(r, and O-ring O(r were also implemented to analyze the spatial pattern of the trees. The distribution of Indian rosewood trees significantly followed inhomogeneous Poisson process (α=0.05. The results of D(r and K2(r showed that the maximum distance to nearest tree was 12 m and density was decreased to this scale. The results of g(r and O(r also revealed the significant aggregation of Indian rosewood trees at scales of 1.5 to 4 m (α=0.05. In general, it was concluded that Indian rosewood trees had positive intraspecific interactions in Indian rosewood Reserve of Khuzestan province and their aggregation showed their facilitative effects on one another.

  14. 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. © 2013 John Wiley & Sons Ltd.

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

    Directory of Open Access Journals (Sweden)

    Haug Joachim T

    2012-08-01

    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.

  16. River food web response to large-scale riparian zone manipulations.

    Directory of Open Access Journals (Sweden)

    J Timothy Wootton

    Full Text Available Conservation programs often focus on select species, leading to management plans based on the autecology of the focal species, but multiple ecosystem components can be affected both by the environmental factors impacting, and the management targeting, focal species. These broader effects can have indirect impacts on target species through the web of interactions within ecosystems. For example, human activity can strongly alter riparian vegetation, potentially impacting both economically-important salmonids and their associated river food web. In an Olympic Peninsula river, Washington state, USA, replicated large-scale riparian vegetation manipulations implemented with the long-term (>40 yr goal of improving salmon habitat did not affect water temperature, nutrient limitation or habitat characteristics, but reduced canopy cover, causing reduced energy input via leaf litter, increased incident solar radiation (UV and PAR and increased algal production compared to controls. In response, benthic algae, most insect taxa, and juvenile salmonids increased in manipulated areas. Stable isotope analysis revealed a predominant contribution of algal-derived energy to salmonid diets in manipulated reaches. The experiment demonstrates that riparian management targeting salmonids strongly affects river food webs via changes in the energy base, illustrates how species-based management strategies can have unanticipated indirect effects on the target species via the associated food web, and supports ecosystem-based management approaches for restoring depleted salmonid stocks.

  17. Assembly of avian mixed-species flocks in Amazonia.

    Science.gov (United States)

    Graves, G R; Gotelli, N J

    1993-01-01

    Diamond's "assembly rules" model posits that competitive interactions among species govern the composition of avifaunas. Although originally applied to islands in archipelagoes, this controversial set of hypotheses is difficult to test because islands differ in habitat and resource availability, colonization history, and stochastic effects. Permanent mixed-species flocks of Amazonian birds are a model system for testing the assembly rules hypothesis because flocks occur in relatively homogeneous tracts of rain forest and because resident species are potentially interactive from minute to minute. To analyze cooccurrence patterns of species in flocks, we used null models that incorporate realistic autecological colonization parameters. Potentially competing pairs of congeneric species with similar ecologies cooccur in flocks less often than expected by chance, resulting in perfect checkerboard distributions. Interactions among more distantly related species, however, appear to have little effect on the assembly of mixed-species flocks. Checkerboard distributions enhance local species diversity within habitats by generating different combinations of species in different flocks. This process may have contributed to the immense species richness of the Amazonian avifauna. PMID:8433996

  18. Hunting for agile prey: trophic specialisation in leptophryid amoebae (Vampyrellida, Rhizaria) revealed by two novel predators of planktonic algae.

    Science.gov (United States)

    Hess, Sebastian

    2017-09-01

    Vampyrellid amoebae (Vampyrellida, Rhizaria) are widespread in freshwater, marine and terrestrial ecosystems and consume a wide range of eukaryotes, e.g. algae, fungi and micrometazoa. Environmental sequences indicate that only a small fraction of their genetic diversity is phenotypically characterised, emphasising the need to further explore unknown vampyrellids and their interactions with prey organisms. This study tests the prey range specificity of three vampyrellid amoebae with 49 strains of three common groups of freshwater algae (Zygnematophyceae, Euglenophyceae and Volvocales), and documents specific interactions by time-lapse microscopy. Two of the amoebae, here introduced as the novel genera Arachnomyxa and Planctomyxa based on morphology and SSU rRNA gene comparisons, display a complementary prey range and consume motile algae, namely Volvocales and Euglenophyceae, respectively. This reveals the existence of specialised 'plankton feeders' in the vampyrellid family Leptophryidae, contrasting with the strikingly broad prey range of Leptophrys vorax. The distinct autecological characteristics found in this group of morphologically rather indistinct amoebae contribute to our knowledge about the vastly understudied vampyrellid amoebae. Furthermore, time-lapse observations suggest that euglenoid movements exerted by the sluggish species of the 'Euglena deses group' as a reaction to vampyrellid contact may serve as an effective defence against microbial predators. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Functional plasticity of benthic macroinvertebrates: implications for trophic dynamics in acid streams

    Energy Technology Data Exchange (ETDEWEB)

    Dangles, O. [Tours University, IRBI CNRS, Tours (France)

    2002-09-01

    Leaf litter breakdown is a key function of headwater-forested streams located in poorly acid-buffered catchments. This paper proceeds from the hypothesis that the ascribed function of stream invertebrate species, especially shredding, may be flexible and subject to local conditions. To test this hypothesis the functions of invertebrate species in streams disturbed by anthropogenic acidification were investigated. The functions were determined by identifying the position of invertebrate species within the benthic food web using gut content analysis, focusing on putative shredders on the assumption that their high abundance would have a strong effect on leaf litter decomposition in acid streams. To understand the processes, food webs and restoration of acid streams, the accuracy of functional feeding group assignments (FFG) were also evaluated. Results showed that acid streams had, in actual fact, very few specialized leaf-shredding species, a fact that could explain the slow leaf detritus processing rates observed in these systems. Primary producers appear to be an alternative resource for shredders, playing an important role in supporting food webs in forested acid streams. The study provides consistent evidence of the risk of lumping genera or even families, containing species with very different autecology, into convenient groups and reducing taxonomic resolution. It also points out the possible misconception that may arise when species-specific functional plasticity is overlooked. 37 refs., 5 tabs., 3 figs., appendix.

  4. The assessment of the habitat and water quality requirements of the stone crayfish (Austropotamobius torrentium and noble crayfish (Astacus astacus species in the rivers from the Anina Mountains (SW Romania

    Directory of Open Access Journals (Sweden)

    Pârvulescu L.

    2011-02-01

    Full Text Available The species Austropotamobius torrentium and Astacus astacus are two species known in the EU directives to require deeper understanding of their autecologic requirements before any sustainable conservation effort could be successfully applied. Therefore, the paper aims to analyze the occurrence of these two species of crayfish in the Anina Mountains (Romania in relation to several physical-chemical indicators measured on site. The results suggest that the anthropogenic impacts registered in some of the sampling sites (e.g. organic pollution and river bed modification might have triggered the disappearance of both species from the areas of the water sheds situated downstream villages and towns, deforestation sites and sewage treatment plants. The analysis suggest that both species might have similar ecologic requirements, with a BMWP score of 8 (out of a possible 10, therefore good indicators of pristine aquatic environments and with a possible toleration to pollution but only up to a moderate level. Nevertheless, the lack of cohabitation of the populations of both species at a local scale was discussed along with two possible explaining hypotheses: behavioral exclusion or different times and/or modalities of dispersal history.

  5. The behaviour of giant clams (Bivalvia: Cardiidae: Tridacninae).

    Science.gov (United States)

    Soo, Pamela; Todd, Peter A

    2014-01-01

    Giant clams, the largest living bivalves, live in close association with coral reefs throughout the Indo-Pacific. These iconic invertebrates perform numerous important ecological roles as well as serve as flagship species-drawing attention to the ongoing destruction of coral reefs and their associated biodiversity. To date, no review of giant clams has focussed on their behaviour, yet this component of their autecology is critical to their life history and hence conservation. Almost 100 articles published between 1865 and 2014 include behavioural observations, and these have been collated and synthesised into five sections: spawning, locomotion, feeding, anti-predation, and stress responses. Even though the exact cues for spawning in the wild have yet to be elucidated, giant clams appear to display diel and lunar periodicities in reproduction, and for some species, peak breeding seasons have been established. Perhaps surprisingly, giant clams have considerable mobility, ranging from swimming and gliding as larvae to crawling in juveniles and adults. Chemotaxis and geotaxis have been established, but giant clams are not phototactic. At least one species exhibits clumping behaviour, which may enhance physical stabilisation, facilitate reproduction, or provide protection from predators. Giant clams undergo several shifts in their mode of acquiring nutrition; starting with a lecithotrophic and planktotrophic diet as larvae, switching to pedal feeding after metamorphosis followed by the transition to a dual mode of filter feeding and phototrophy once symbiosis with zooxanthellae ( Symbiodinium spp.) is established. Because of their shell weight and/or byssal attachment, adult giant clams are unable to escape rapidly from threats using locomotion. Instead, they exhibit a suite of visually mediated anti-predation behaviours that include sudden contraction of the mantle, valve adduction, and squirting of water. Knowledge on the behaviour of giant clams will benefit

  6. Symplasmic and apoplasmic transport inside feather moss stems of Pleurozium schreberi and Hylocomium splendens.

    Science.gov (United States)

    Sokolowska, K; Turzanska, M; Nilsson, M-C

    2017-11-10

    The ubiquitous feather mosses Pleurozium schreberi and Hylocomium splendens form a thick, continuous boundary layer between the soil and the atmosphere, and play important roles in hydrology and nutrient cycling in tundra and boreal ecosystems. The water fluxes among these mosses and environmental factors controlling them are poorly understood. The aim of this study was to investigate whether feather mosses are capable of internal transport and to provide a better understanding of species-specific morphological traits underlying this function. The impacts of environmental conditions on their internal transport rates were also investigated. Cells involved in water and food conduction in P. schreberi and H. splendens were identified by transmission electron microscopy. Symplasmic and apoplasmic fluorescent tracers were applied to the moss stems to determine the routes of internal short- and long-distance transport and the impact of air humidity on the transport rates. Symplasmic transport over short distances occurs via food-conducting cells in both mosses. Pleurozium schreberi is also capable of apoplasmic internal long-distance transport via a central strand of hydroids. These are absent in H. splendens. Reduced air humidity significantly increased the internal transport of both species, and the increase was significantly faster for P. schreberi than for H. splendens. Pleurozium schreberi and Hylocomium splendens are capable of internal transport but the pathway and conductivity differ due to differences in stem anatomy. These results help explain their varying desiccation tolerance and possibly their differing physiology and autecology and, ultimately, their impact on ecosystem functioning. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  7. Climate change and Southern Ocean ecosystems I: how changes in physical habitats directly affect marine biota.

    Science.gov (United States)

    Constable, Andrew J; Melbourne-Thomas, Jessica; Corney, Stuart P; Arrigo, Kevin R; Barbraud, Christophe; Barnes, David K A; Bindoff, Nathaniel L; Boyd, Philip W; Brandt, Angelika; Costa, Daniel P; Davidson, Andrew T; Ducklow, Hugh W; Emmerson, Louise; Fukuchi, Mitsuo; Gutt, Julian; Hindell, Mark A; Hofmann, Eileen E; Hosie, Graham W; Iida, Takahiro; Jacob, Sarah; Johnston, Nadine M; Kawaguchi, So; Kokubun, Nobuo; Koubbi, Philippe; Lea, Mary-Anne; Makhado, Azwianewi; Massom, Rob A; Meiners, Klaus; Meredith, Michael P; Murphy, Eugene J; Nicol, Stephen; Reid, Keith; Richerson, Kate; Riddle, Martin J; Rintoul, Stephen R; Smith, Walker O; Southwell, Colin; Stark, Jonathon S; Sumner, Michael; Swadling, Kerrie M; Takahashi, Kunio T; Trathan, Phil N; Welsford, Dirk C; Weimerskirch, Henri; Westwood, Karen J; Wienecke, Barbara C; Wolf-Gladrow, Dieter; Wright, Simon W; Xavier, Jose C; Ziegler, Philippe

    2014-10-01

    Antarctic and Southern Ocean (ASO) marine ecosystems have been changing for at least the last 30 years, including in response to increasing ocean temperatures and changes in the extent and seasonality of sea ice; the magnitude and direction of these changes differ between regions around Antarctica that could see populations of the same species changing differently in different regions. This article reviews current and expected changes in ASO physical habitats in response to climate change. It then reviews how these changes may impact the autecology of marine biota of this polar region: microbes, zooplankton, salps, Antarctic krill, fish, cephalopods, marine mammals, seabirds, and benthos. The general prognosis for ASO marine habitats is for an overall warming and freshening, strengthening of westerly winds, with a potential pole-ward movement of those winds and the frontal systems, and an increase in ocean eddy activity. Many habitat parameters will have regionally specific changes, particularly relating to sea ice characteristics and seasonal dynamics. Lower trophic levels are expected to move south as the ocean conditions in which they are currently found move pole-ward. For Antarctic krill and finfish, the latitudinal breadth of their range will depend on their tolerance of warming oceans and changes to productivity. Ocean acidification is a concern not only for calcifying organisms but also for crustaceans such as Antarctic krill; it is also likely to be the most important change in benthic habitats over the coming century. For marine mammals and birds, the expected changes primarily relate to their flexibility in moving to alternative locations for food and the energetic cost of longer or more complex foraging trips for those that are bound to breeding colonies. Few species are sufficiently well studied to make comprehensive species-specific vulnerability assessments possible. Priorities for future work are discussed. © 2014 John Wiley & Sons Ltd.

  8. PET microplastics do not negatively affect the survival, development, metabolism and feeding activity of the freshwater invertebrate Gammarus pulex.

    Science.gov (United States)

    Weber, Annkatrin; Scherer, Christian; Brennholt, Nicole; Reifferscheid, Georg; Wagner, Martin

    2018-03-01

    Over the past decade, microscopic plastic debris, known as microplastics, emerged as a contaminant of concern in marine and freshwater ecosystems. Although regularly detected in aquatic environments, the toxicity of those synthetic particles is not well understood. To address this, we investigated whether the exposure to microplastics adversely affects the amphipod Gammarus pulex, a key freshwater invertebrate. Juvenile (6-9 mm) and adult (12-17 mm) individuals were exposed to irregular, fluorescent polyethylene terephthalate fragments (PET, 10-150 μm; 0.8-4,000 particles mL -1 ) for 24 h. Results show that body burden after 24 h depends on the dose and age of G. pulex with juveniles ingesting more microplastics than adults. After chronic exposure over 48 d, microplastics did not significantly affect survival, development (molting), metabolism (glycogen, lipid storage) and feeding activity of G. pulex. This demonstrates that even high concentrations of PET particles did not negatively interfere with the analyzed endpoints. These results contradict previous research on marine crustaceans. Differences may result from variations in the exposure regimes (e.g., duration, particle concentrations), plastic characteristics (e.g., type, size, shape, additives) as well as the species-specific morphological, physiological and behavioral traits. As a detritivorous shredder G. pulex is adapted to feed on non-digestible materials and might, therefore, be less sensitive towards exposure to synthetic particles. Accordingly, we argue that the autecology needs to be taken into account and that research should focus on identifying traits that render species susceptible to microplastic exposure. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. 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.

  10. 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

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

    Directory of Open Access Journals (Sweden)

    Hemm, Verena

    2012-12-01

    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.

  12. Mise au point d' un modele cartographique pour la description des stations forestieres en Ardenne belge

    Directory of Open Access Journals (Sweden)

    Lejeune P.

    2002-01-01

    Full Text Available Development of a cartographic mdel for the forest site types delineation in the Belgian Ardenne. The paper presents an original method dealing with the forest site types delineation. The suggested method consists in integrating a typological key in a GIS aiming at producing a thematic map that describes forest site types. Data used are the soil map of Belgium (digitized at the scale 1:20,000 and a digital elevation model built from a topographic map (scale 1:10,000. The typological key is mainly based on the methodology used by Thill et al. (1988 in the site types system for central Ardenne, the potential vegetation map of Sougnez and Dethioux (1975 and the ecoregion map of Delvaux and Galoux (1962. In that respect, site types are closely linked to the soil map and the phytosociological classification. So, they can be connected to the afforestation guide and different phytosociological and autecological studies concerning forest species. It is then possible to map the potential habitats or the site potentialities related to tree species. The key is valid for the Ardenne ecoregion located in Southern Belgium (elevation higher than 300 m. It has to be validated through an intensive use in the field, taking into account its imprecision linked to the types of collected data, chieffly those being digitized. The integration of such a tool in a SIG can be considered as an original way in terms of integrated forest management or forest sites description in the context of the project ""Natura 2000"" launched by the European Union. The study has been carried out within the framework of an experimental integrated management project concerning the Saint-Hubert forest (17,000 ha.

  13. Effects of biotic and abiotic factors on the accumulation of radionuclides in Fucus vesiculosus L

    International Nuclear Information System (INIS)

    Carlson, Lena.

    1990-01-01

    Fucus vesiculosus has been used as an indicator for the occurrence of radionuclides in the marine environment. A prerequisite in using biological organisms as indicators is that the autecology of the organisms in question be well known. Growth, reproduction and individual biomass changes of tissues of different ages were studied in a Fucus vesiculosus population from the Oeresund, southern Sweden. The new vegetative fronds grown during the year accounted for about 80% of the total plant biomass in the autumn and this could affect the total activity concentration of long-lived radionuclides measured in whole plants of F. vesiculosus. Thus, a discharge of long-lived radionuclides during winter or spring gives a higher increase than a discharge during autumn. Differences in uptake and release of 54 Mn and 60 Co were observed between F. vesiculosus and its epiphytes but also between different tissues within the Fucus plant. Highest uptake and release were measured for the filamentous epiphyte Pilayella littoralis followed by the new vegetative fronds of F. vesiculosus after transplantation in situ from an area outside Barsebaeck nuclear power station, southern Sweden, to an area with low concentration of the radionuclides studied and vice versa. Salinity effects on the accumulation of radionuclides in F. vesiculosus were studied experimentally. Accumulation of 137 Cs, 54 Mn, 65 Zn and 60 Co was significantly higher in algae grown at 8 permille than at 15 and 24 permille, respectively. Most pronounced salinity effects were observed for 137 Cs. The impact of the Chernobyl accident was investigated in the Baltic Sea using F. vesiculosus. The Chernobyl accident contributed to the radioactivity in the Baltic Sea primarily concerning radiocaesium. (author)

  14. Toward Modeling the Resistance and Resilience of "Below-ground" Fungal Communities: A Mechanistic and Trait-Based Approach.

    Science.gov (United States)

    Falconer, Ruth E; Otten, Wilfred; White, Nia A

    2015-01-01

    The role of fungi in shaping ecosystems is well evidenced and there is growing recognition of their importance among scientists and the general public. Establishing and separating the role of key local (soil chemical, biological, and physical properties) and global (climate, dispersal limitation) drivers in fungal community structure and functioning is currently a source of frustration to mycologists. The quest to determine niche processes and environmental characteristics shaping fungal community structure, known to be important for plant and animal communities, is proving difficult, resulting in the acknowledgment that niche neutral processes (climate, dispersal limitations) may dominate. The search for predictable patterns in fungal community structure may have been restricted as the "appropriate" scales at which to measure community structure and characterize the environment have not been fully determined yet, and the focus on taxonomy makes it difficult to link environmental characteristics to fungal traits. While key determinants of microbial community composition have been uncovered for some functional groups, the differential response of functional groups is largely unknown. Before we can truly understand what drives the development of microbial community structure, an understanding of the autecology of major fungal taxa and how they interact with their immediate environment (from the micro- up to kilometer scale) is urgently needed. Furthermore, key information and empirical data is missing at the microscale due to experimental difficulties in mapping this heterogeneous and opaque environment. We therefore present a framework that would help generate this much-needed empirical data and information at the microscale, together with modeling approaches to link the spatial and temporal scales. The latter is important as we propose that there is much to be gained by linking our understanding of fungal community responses across scales, in order to develop

  15. 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 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.

  16. 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. © 2015 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

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

    Directory of Open Access Journals (Sweden)

    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

  18. 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

  19. An Experimental Insight into Extracellular Phosphatases – Differential Induction of Cell-Specific Activity in Green Algae Cultured under Various Phosphorus Conditions

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    Jaroslav Vrba

    2018-02-01

    Full Text Available Extracellular phosphatase activity (PA has been used as an overall indicator of P depletion in lake phytoplankton. However, detailed insights into the mechanisms of PA regulation are still limited, especially in the case of acid phosphatases. The novel substrate ELF97 phosphate allows for tagging PA on single cells in an epifluorescence microscope. This fluorescence-labeled enzyme activity (FLEA assay enables for autecological studies in natural phytoplankton and algal cultures. We combined the FLEA assay with image analysis to measure cell-specific acid PA in two closely related species of the genus Coccomyxa (Trebouxiophyceae, Chlorophyta isolated from two acidic lakes with distinct P availability. The strains were cultured in a mineral medium supplied with organic (beta-glycerol phosphate or inorganic (orthophosphate P at three concentrations. Both strains responded to experimental conditions in a similar way, suggesting that acid extracellular phosphatases were regulated irrespectively of the origin and history of the strains. We found an increase in cell-specific PA at low P concentration and the cultures grown with organic P produced significantly higher (ca. 10-fold PA than those cultured with the same concentrations of inorganic P. The cell-specific PA measured in the cultures grown with the lowest organic P concentration roughly corresponded to those of the original Coccomyxa population from an acidic lake with impaired P availability. The ability of Coccomyxa strains to produce extracellular phosphatases, together with tolerance for both low pH and metals can be one of the factors enabling the dominance of the genus in extreme conditions of acidic lakes. The analysis of frequency distribution of the single-cell PA documented that simple visual counting of ‘active’ (labeled and ‘non-active’ (non-labeled cells can lead to biased conclusions regarding algal P status because the actual PA of the ‘active’ cells can vary from

  20. 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.

  1. 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.

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    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.

  2. 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.

  3. 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 change from a freshwater to mesosaline 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

  4. Multidimensional tree niches in a tropical dry forest.

    Science.gov (United States)

    Pulla, Sandeep; Suresh, Hebbalalu S; Dattaraja, Handanakere S; Sukumar, Raman

    2017-05-01

    argue, based on a survey of the literature, that many of the observed niche differences in tropical forests are more parsimoniously viewed as autecological differences between species that exist independently of interspecific interactions. © 2017 by the Ecological Society of America.

  5. 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.

  6. 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

    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.

  7. 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