Sökning: "extinction risk"

Visar resultat 1 - 5 av 38 avhandlingar innehållade orden extinction risk.

  1. 1. Population Dynamics and Conservation of the Sand Lizard (Lacerta agilis) on the Edge of its Range

    Författare :Sven-Åke Berglind; Pekka Pamilo; Per Sjögren-Gulve; Coulson Tim; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Ecology; demography; extinction; habitat; Lacerta agilis; management; metapopulation; peripheral populations; population dynamics; population viability analysis; reintroduction; reptiles; umbrella species; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi;

    Sammanfattning : The sand lizard (Lacerta agilis) reaches the northern periphery of its distribution in south-central Sweden, where small, isolated relict populations occur in pine heath forests on sandy sediments. Modern forestry and fire suppression have reduced the amount of suitable open habitat for the species in this area and seem to be important for its decline. LÄS MER

  2. 2. Food Webs, Models and Species Extinctions in a Stochastic Environment

    Författare :Patrik Karlsson; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Ekologi; Ecology; functional redundancy; trophospecies; species aggregation; environmental stochasticity; interaction strength; spectral colour; food web structure; food webs; extinction risk;

    Sammanfattning : In light of the current global mass extinction of species, ecologists are facing great challenges. In order to reverse the path towards additional extinctions early warning systems to guide management actions need to be developed. LÄS MER

  3. 3. Species extinctions in food webs : local and regional processes

    Författare :Anna Eklöf; Bo Ebenman; Peter Münger; Marcel Holyoak; Linköpings universitet; []
    Nyckelord :Extinction; food web; metacommunity; dispersal; species loss; migration; habitat fragmentation; connectance; NATURAL SCIENCES; NATURVETENSKAP;

    Sammanfattning : Loss of biodiversity is one of the most severe threats to the ecosystems of the world. The major causes behind the high population and species extinction rates are anthropogenic activities such as overharvesting of natural populations, pollution, climate change and destruction and fragmentation of natural habitats. LÄS MER

  4. 4. Demand for Extinguishing Media in Manual Fire Fighting

    Författare :Stefan Särdqvist; Avdelningen för Brandteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; fire fighting; Fire brigade; fire suppression; extinguishing agents; extinction; Technological sciences; Teknik;

    Sammanfattning : Risk analysis and intervention planning are important in fire prevention and risk management strategies. This study has shown that it is possible to use fire safety engineering models to estimate the development of fires on a realistic scale, and the corresponding requirement for extinguishing media. LÄS MER

  5. 5. Multi-Dimensional Quantitative Laser-based Diagnostics - Development and Practial Applications

    Författare :Rikard Wellander; Förbränningsfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Post injection; Structured illumination; Mie scattering; Dense sprays; Extinction coefficient; Signal attenuation; Laser extinction; Multiple scattering; Scattering measurements; Planar laser induced fluorescence; Time resolved; Imaging through turbulent media; Three-dimensional image acquisition; Diesel particulate filter regeneration; Wall impingent; Biodiesel; LII; Large-bore gas Engine; Pre-chamber ignition; Fysicumarkivet A:2014:Wellander;

    Sammanfattning : Laser based optical diagnostic methods are routinely used in combustion research. Many of the more common approaches are based on illuminating a cross-section of the sample with a thin laser sheet. For example, by targeting an electronic transition in a molecule, its concentration within the plane illuminated by the laser sheet can be deduced. LÄS MER