Sökning: "Ecology"

Visar resultat 1 - 5 av 1688 avhandlingar innehållade ordet Ecology.

  1. 1. Stopover Ecology of Mallards Where, when and how to do what?

    Detta är en avhandling från Växjö : Linnaeus University Press

    Författare :Daniel Bengtsson; Jonas Waldenström; W. Michael Eichholtz; [2016]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Age characters; body condition; departure decision; effects of influenza A virus; habitat selection; mallard; movement; Ottenby Bird Observatory; stopover ecology; weather; wild birds; Ecology; Ekologi;

    Sammanfattning : The mallard (Anas platyrhynchos) is the most numerous and widespread duck in the northern hemisphere and a model species in ecology and harvest management. Migration is a crucial life stage for many birds and understanding the drivers of migration has important implications for conservation biology and assessment of animal population responses to global changes. LÄS MER

  2. 2. Evolutionary ecology of arctic char (Salvelinus alpinus (L.)) : Intra- and interspecific interactions in circumpolar populations

    Detta är en avhandling från Uppsala : Acta Universitatis Upsaliensis

    Författare :Johan Hammar; [1998]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; Arctic char; Salvelinus alpinus; biogeography; niche; life history; population ecology; intra- and interspecific interactions; cannibalism; competition; landlocked; marginal populations; species border; Ekologi; NATURAL SCIENCES Biology Terrestrial; freshwater and marine ecology; NATURVETENSKAP Biologi Terrestisk; limnisk och marin ekologi; Animal Ecology; zooekologi;

    Sammanfattning : This thesis examines a suite of ecological and genetic mechanisms influencing the fundamental and realized niche borders of European and North American populations of the Arctic char (Salvelinus alpinus (L.)) species complex in allopatry as well as in sympatry with brown trout (Salmo trutta) or brook trout (Salvelinus fontinalis). LÄS MER

  3. 3. Methane dynamics in northern wetlands: Significance of vascular plants

    Detta är en avhandling från Department of Ecology, Lund University

    Författare :Anna Joabsson; [2001]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; aquatic ecology; marine biology; Hydrobiology; Växtekologi; Plant ecology; climate change; arctic wetlands; northern wetlands; plant-microbe interactions; methane emission; vascular plants; limnology; Marinbiologi; limnologi; akvatisk ekologi; Ecology; Ekologi;

    Sammanfattning : The studies presented in Papers I to VI illustrate several different aspects of the impact of vascular plants on methane emissions from northern natural wetlands. The subject has been approached on different scales, ranging from the study of microbial substrates in the vicinity of a single plant root, to an attempt to extrapolate some of the results to the entire northern hemisphere north of 50°N. LÄS MER

  4. 4. Biodiversity in Agricultural Landscapes: Landscape and Scale-Dependent Effects of Organic Farming

    Detta är en avhandling från Department of Ecology, Lund University

    Författare :Maj Rundlöf; [2007]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Djurekologi; Natural science; Naturvetenskap; Ekologi; Animal ecology; plants; spatial scales; species richness; Ecology; landscape ecology; agri-environment schemes; farming practice; conservation; butterflies; bumble bees;

    Sammanfattning : Declines in the distribution and abundance of many farmland species during recent decades have been attributed to agricultural intensification. Agri-environment schemes are commonly used in Europe to reduce this loss of farmland biodiversity, but their effectiveness may depend on several external factors. LÄS MER

  5. 5. Butterfly Diversity and Dispersal in Fragmented Grasslands

    Detta är en avhandling från Department of Ecology, Lund University

    Författare :Erik Öckinger; [2006]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Naturvetenskap; Djurekologi; Animal ecology; Ekologi; Ecology; Lepidoptera; Landscape ecology; Insects; Species richness; Fragmentation; Mobility; Natural science; Source-sink dynamics; Metapopulations;

    Sammanfattning : During the last decades, the distribution and abundance of many European species of birds, plants and insects in agricultural landscapes have declined due to agricultural intensification. To be able to mitigate these declines, it is essential to know the relative importance on local and regional ecological processes on population persistence and patterns of species richness. LÄS MER