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Visar resultat 1 - 5 av 220 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Effects of size-dependent predation and competition on population and community dynamics

   Författare :Karin Nilsson; Lennart Persson; Volker Rudolf; Umeå universitet; []
   Nyckelord :size-structure; cannibalism; resource competition; predation; emergent facilitation; population regulation; population dynamics; overcompensation; density-dependence; cycles; zooekologi; Animal Ecology;

   Sammanfattning : Most animals grow substantially during their lifetime and change in competitive ability, predatory capacity and their susceptibility to predation as they grow. This thesis addresses the implications of this on regulation and dynamics within populations as well as between population interactions. LÄS MER

3. 2. 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

4. 3. Population viability analysis for plants : practical recommendations and applications

   Författare :Satu Ramula; Kari Lehtilä; Patrik Dinnétz; Esa Ranta; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; demography; matrix population models; population viability analysis; population growth rate; stochastic models; Biology; Biologi;

   Sammanfattning : Population viability analysis (PVA) is commonly used in conservation biology to predict population viability in terms of population growth rate and risk of extinction. However, large data requirements limit the use of PVA for many rare and threatened species. LÄS MER

5. 4. Population divergence at small spatial scales : – theoretical and empirical investigations in perch

   Författare :Sara Bergek; Mats Björklund; Teija Aho; Sarah Goodacre; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Perca fluviatilis L.; Perch; Small scale genetic differentiation; Morphometrics; Isolation by distance; Dispersal; Gene flow; Microsatellites; Spatiotemporal stability; Barriers; Biology; Biologi; Terrestrial; freshwater and marine ecology; Terrestrisk; limnisk och marin ekologi; Animal Ecology; zooekologi;

   Sammanfattning : Genetically structured populations arise when gene flow between groups of individuals is hindered by geographical, behavioural or temporal barriers. The identification of such groups is important for understanding evolution and has large implications for conservation concern. LÄS MER

7. 5. Genomics of population decline

   Författare :Tom van der Valk; Katerina Guschanski; Aylwyn Scally; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; genetic diversity; minimal-invasive samples; population decline; inbreeding; genetic purging; eastern gorillas; Dryas monkey; Biologi med inriktning mot zooekologi; Biology with specialization in Animal Ecology;

   Sammanfattning : With human populations forecasted to grow in the next decades, many mammals face increasing anthropogenic threats. The consequential population declines are a precursor to extinctions, as small populations are not only more sensitive to stochastic events, but reduction in population size is generally also followed by a decrease in genetic diversity, which in turn reduces adaptive potential and fitness of the population. LÄS MER