Sökning: "Historical ecology"

Visar resultat 21 - 25 av 97 avhandlingar innehållade orden Historical ecology.

  1. 21. 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

  3. 22. Losing track of time : causes and solutions for the problematic determination of Baltic cod age

    Författare :Yvette Heimbrand; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Age is a fundamental parameter in biology and fishery science to estimate growth and population parameters. Losing track of time, in the sense of lacking reliable estimates of age and growth creates substantial problems for managing difficult-to-age-species. This thesis explores the use of fish otolith chemistry to improve age determination. LÄS MER

  4. 23. Landlocked Atlantic salmon Salmo salar L. and trout Salmo trutta L. in the regulated River Klarälven, Sweden : Implications for conservation and management

    Författare :Johnny R Norrgård; Eva Bergman; Hans Lundqvist; Karlstads universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Biology; Biologi;

    Sammanfattning : Conservation and management of migratory salmonids requires an understanding of their ecology at multiple scales, and a holistic view, including assessment of historical and present anthropogenic impacts. In the regulated River Klarälven, with 11 hydropower dams, populations of landlocked Atlantic salmon Salmo salar and migratory brown trout Salmo trutta have declined due to human activities. LÄS MER

  5. 24. Moisture as a regulator of microbial life in soil

    Författare :Ainara Leizeaga; MEMEG; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Climate change models predict an increase in the intensity and frequency of drought periods as well as precipitation events. Moisture and its fluctuations have a large impact on soil microorganisms, which are key drivers of the terrestrial carbon (C) cycle. LÄS MER

  7. 25. Plant community assembly and biodiversity: a spatio-temporal perspective

    Författare :Oliver Purschke; Biodiversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; phylogenetic diversity; null model; life-history traits; land use history; landscape fragmentation; dispersal; functional diversity; semi-natural grasslands;

    Sammanfattning : Biodiversity, the variety of life at all organisational levels from genes to ecosystems, affects ecosystem processes and therefore the goods and services ecosystems provide. More research is needed to provide new insights into biodiversity changes and the processes that drive these changes, in order to formulate effective policy and conservation measures to stop the ongoing biodiversity loss. LÄS MER