Sökning: "species border"

Visar resultat 1 - 5 av 25 avhandlingar innehållade orden species border.

  1. 1. Small remnant habitats : Important structures in fragmented landscapes

    Författare :Jessica Lindgren; Sara Cousins; Regina Lindborg; Adam Kimberley; Ove Eriksson; Hans Henrik Bruun; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Alpha-diversity; Beta-diversity; Biological pest control; Canopy cover; Connectivity; Ecosystem function; Fleshy fruits; Forest edge; Forest management; Forest specialist species; Fragmentation; Functional diversity; Gamma-diversity; Grassland specialist species; Green infrastructure; Habitat amount hypothesis; Island biogeography; Midfield islets; Plant diversity; Plant-pollinator interaction; Pollination; Remnant habitat; Seed predation; Small habitats; Species richness; Structural heterogeneity; Physical Geography; naturgeografi;

    Sammanfattning : The world-wide intensification of agriculture has led to a decline in species richness due to land use change, isolation, and fragmentation of natural and semi-natural habitats in agricultural and forestry landscapes. As a consequence, there is a current landscape management focus on the importance of green infrastructure to mitigate biodiversity decline and preserve ecosystem functions e. LÄS MER

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

    Författare :Johan Hammar; Uppsala universitet; []
    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; Terrestrial; freshwater and marine ecology; 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

  4. 3. Markets, mixtures and molecular methods : Investigating medicinal plant and edible orchid diversity in Tanzania and Zambia

    Författare :Sarina Veldman; Hugo J. de Boer; Tinde R. van Andel; Barbara Gravendeel; Joseph N. Otieno; Julie Hawkins; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; DNA barcoding; Africa; Species delimitation; Orchids; Medicinal plants;

    Sammanfattning : Medicinal plants are an important source of primary healthcare for many people in Tanzania. These medicinal plants are harvested from the wild, and increasing commercial trade poses a serious threat to local plant populations. Currently it is unknown which species are traded and in what amounts. LÄS MER

  5. 4. Effects of landscape context on populations of bumblebees

    Författare :Anna Persson; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Apoidea; Bombus; Campanula; agriculture; land-use intensity; complexity; garden; grassland; field border; MFC; pollination; Factor Analysis;

    Sammanfattning : To investigate recent declines in bumblebee populations, I carried out landscape analyses, made field studies of bumblebees, flowering plants and pollination in an agricultural region in southernmost Sweden. Studies were carried out in landscapes of contrasting agricultural intensity and land-cover configuration; "simple" landscapes highly dominated by large crop fields, and "complex" with mixed farming, grasslands and smaller fields. LÄS MER

  7. 5. Sphagnum limits : Physiology, morphology and climate

    Författare :Charles Campbell; Håkan Rydin; Gustaf Granath; Sebastian Sundberg; Bengt-Gunnar Jonsson; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Sphagnum; ecology; bryophyte; winter; species distribution models; low temperature; plant structure; water economy; Biology with specialization in Ecological Botany; Biologi med inriktning mot ekologisk botanik;

    Sammanfattning : Sphagnum is the most important plant genus in terms of terrestrial carbon cycling. It and the habitats it creates store an equivalent of ~68% of the CO2 in the atmosphere. The genus has little dispersal limitation and the mire habitats are functionally similar at global scales. LÄS MER