Sökning: "high quality habitat"

Visar resultat 1 - 5 av 50 avhandlingar innehållade orden high quality habitat.

1. 1. The long-term decline of the grey-sided vole (Clethrionomys rufocanus) in boreal Sweden: importance of focal forest patch and matrix

   Författare :Pernilla Christensen; Birger Hörnfeldt; Rolf A. Ims; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; : Destructive sampling; high quality habitat; focal habitat; landscape; habitat fragmentation; threshold; clear-cut; patch size and quality; long-term time-series; Terrestrial ecology; Terrestisk ekologi;

   Sammanfattning : There has been a long-term decline in number of cyclic vole populations in boreal Sweden since the 1970s. Several hypotheses have been suggested to explain this decline. Commonly for C. glareolus, C. LÄS MER

3. 2. Through the eyes of a woodpecker: Understanding habitat selection, territory quality and reproductive decisions from individual behaviour

   Författare :Ola Olsson; Biodiversitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; reproductive success; territory quality; habitat selection; giving-up density; Bayesian processes; foraging; Picidae; lesser spotted woodpecker; Dendrocopos minor; conservation; Animal ecology; Djurekologi;

   Sammanfattning : In this thesis I present some connections between foraging behaviour and reproductive success, time budget, tree species use, and habitat selection. The thesis is based upon both theoretical and empirical work. All empirical studies concern a south Swedish population of lesser spotted woodpeckers Dendrocopos minor, studied between 1990 and 1996. LÄS MER

4. 3. The function of seasonal habitat shifts in two congeneric mayflies in a boreal river

   Författare :Olle Söderström; Umeå universitet; []
   Nyckelord :LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; Habitat utilization; diel activity; orientation; predation; life-history; temperature; food quality; mayflies; Parameletus chelifer; Parameletus minor;

   Sammanfattning : Unregulated North Swedish rivers show large seasonal variations in their physical characteristics. During winter the whole littoral zone freezes solid, and in spring the water flow increases rapidly and the same areas become flooded. The two mayflies Parameletus chelifer and P. minor are common in the North Swedish river Vindelälven. LÄS MER

5. 4. Semi-natural grasslands: landscape, history and plant species diversity

   Författare :Lotten Jönsson; Institutionen för naturgeografi och ekosystemvetenskap; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; aerial photographs; Land-use history; cadastral maps; habitat continuity; fragmentation; landscape context; habitat connectivity;

   Sammanfattning : This thesis explores the impact of past and present landscape and habitat structure on present levels of vascular plant species diversity within fragmented semi-natural grasslands. Within the Jordtorp-area, a mosaic agricultural landscape on the island of Öland (Sweden), historical land-use changes and the development of semi-natural grasslands was characterized, over a time-period of almost 300 years, using historical maps, aerial photographs and a high-resolution imagery. LÄS MER

7. 5. The Ecological Role of Roadside Stormwater Ponds - Potential to Support Biodiversity

   Författare :Zhenhua Sun; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Macroinvertebrates; Stormwater ponds; DNA metabarcoding; Sediments; High throughput sequencing; Road runoff; Water quality; Aquatic biodiversity;

   Sammanfattning : The increased recognition that roads may impair the aquatic environment and ecosystems has led to a shift from conventional drainage systems toward blue-green solutions such as stormwater ponds. Research on blue-green stormwater solutions has until now mainly focused on water quantity and quality. LÄS MER