Sökning: "freshwater and marine ecology"
Visar resultat 1 - 5 av 131 avhandlingar innehållade orden freshwater and marine ecology.
1. Evolutionary ecology of arctic char (Salvelinus alpinus (L.)) : Intra- and interspecific interactions in circumpolar populations
Sammanfattning : This thesis examines a suite of ecological and genetic mechanisms influencing the fundamental and realized niche borders of European and North American populations of the Arctic char (Salvelinus alpinus (L.)) species complex in allopatry as well as in sympatry with brown trout (Salmo trutta) or brook trout (Salvelinus fontinalis). LÄS MER
Sammanfattning : Cross-boundary movements of energy and material are ubiquitous. Freshwater ecosystems receive nutrients, dissolved, and particulate organic matter from adjacent terrestrial ecosystems, whereas terrestrial ecosystems mainly receive prey organisms and detritus deposited by physical processes such as floods from freshwater ecosystems. LÄS MER
Sammanfattning : Biological invasions are an important issue of global change and an increased understanding of invasion processes is of crucial importance for both conservation managers and international trade. In this thesis, I have studied the invasion of the brown seaweed Fucus evanescens, to investigate the fate and effect of a perennial, habitat-forming seaweed introduced to a coastal ecosystem. LÄS MER
4. Variation in Pseudorchis albida s.l. (Orchidaceae) and Carex capitata s.l. (Cyperaceae) : Morphology, genetic diversity, ecology and systematics
Sammanfattning : In the Scandinavian flora, several species-pairs where one member is an alpine species andthe other is a closely related lowland species, have been described. The aim of this studywas to investigate two such examples, viz. Pseudorchis albida s.s. LÄS MER
Sammanfattning : Pigmentation in the freshwater isopod Asellus aquaticus differed between two habitats. Asellus were lighter pigmented in stands of submerged stonewort vegetation, than in nearby reed stands. Moreover, Asellus pigmentation became lighter with time in recently established stonewort stands. LÄS MER