Sökning: "population growth rate"

Visar resultat 6 - 10 av 225 avhandlingar innehållade orden population growth rate.

1. 6. Variation in age and size at maturation in two benthic crustaceans in the Gulf of Bothnia

   Författare :Kjell Leonardsson; J. Ekman; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Age at maturation; alternative prey; Bergmanris rule; cannibalism; growth; life-history theory; mortality; Mvoxocephalus quadricornis; poikilotherm; Pontoporeia affinis; population dynamics; risk- taking behaviour; Saduria entomon; size at maturation; temperature;

   Sammanfattning : The thesis deals with variation in age and size at maturation in Saduria entomon and Pontoporeia affinis along a depth gradient in the Gulf of Bothnia, Sweden. I have analysed at what sizes and ages animals should mature in relation to growth and mortality conditions. LÄS MER

3. 7. Dynamics of omnivorous crayfish in freshwater ecosystems

   Författare :Karin Olsson; Biologiska institutionen; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; crayfish; freshwater ecosystems; niche width; growth rate; stable isotope analysis; recruitment; RNA:DNA analysis; Ecology; food availability and quality; trophic position; population dynamics;

   Sammanfattning : In this thesis I examine the dynamics of crayfish in streams and lakes. I have studied the influence of abiotic and biotic factors on abundance, growth, trophic position, niche breadth, and recruitment of crayfish, by conducting field studies, an outdoor channel experiment and timeseries analysis. LÄS MER

4. 8. Population size, viability and genetic diversity in the orchid Gymnadenia conopsea

   Författare :Linus Söderquist; Nina Sletvold; Sophie Karrenberg; Hans Jacquemyn; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; demography; extinction probability; genetic diversity; genetic rescue; genetic structure; Gymnadenia conopsea; orchid conservation; population viability; population size; Biology with specialization in Ecological Botany; Biologi med inriktning mot ekologisk botanik;

   Sammanfattning : In this thesis, I combined controlled crosses with genetic and demographic data to examine how a main conservation value indicator, population size, was associated with estimates of population viability. I focused on the still common, but decreasing, perennial orchid Gymnadenia conopsea at two spatial scales—locally on the island Öland, in SE Sweden, and regionally across Scandinavia. LÄS MER

5. 9. Plant ecological studies related to restoration of a degraded ecosystem in central Tanzania

   Författare :Shadrack Eliapenda; Ingvar Backéus; Karin Bengtsson; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Developmental biology; Conservation; land degradation; population growth rate; population structure; regeneration; Utvecklingsbiologi; Developmental biology; Utvecklingsbiologi; Ecological Botany; Ekologisk botanik;

   Sammanfattning : Kondoa Irangi area is among the most degraded ecosystems in Central Tanzania as a result of heavygrazing, fire, collection of fuelwood and improper cultivation practices. The restoration process of thisdegraded ecosystem through natural regeneration is slowed by the semi-arid climate of the area combinedwith poor soil nutrient status. LÄS MER

7. 10. Public Health Aspects of Preterm Birth. Studies using Scandinavian population-based data

   Författare :Nils-Halvdan Morken; Göteborgs universitet; []
   Nyckelord :preterm birth; preterm delivery; subgroups; spontaneous preterm birth; iatrogenic preterm birth; birth weight; fetal growth; reference population; outcome; cerebral palsy; prediction;

   Sammanfattning : Background: Preterm birth is an unresolved serious global health problem. Research must be multi-disciplinary, with assessment of risk factors and causative agents at many levels of observation. Such an important level is the public health aspect of preterm birth. LÄS MER