Sökning: "Marin ekologi"

Visar resultat 16 - 20 av 275 avhandlingar innehållade orden Marin ekologi.

1. 16. Ecology and Evolution of Adaptive Morphological Variation in Fish Populations

   Författare :Richard Svanbäck; Peter Eklöv; Lennart Persson; Beren Robinson; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; competition; functional morphology; individual specialization; inter-individual variation; intra-population variation; morphological variation; ontogeny; Perca fluviatilis; perch; phenotypic plasticity; predation; trade-offs; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi;

   Sammanfattning : The work in this thesis deals with the ecology and evolution of adaptive individual variation. Ecologists have long used niche theory to describe the ecology of a species as a whole, treating conspecific individuals as ecological equivalent. LÄS MER

3. 17. Plants go with the flow : predicting spatial distribution of plant species in the boreal forest

   Författare :Ursula Zinko; Christer Nilsson; Håkan Rydin; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; boreal forest; vascular plant; species richness; wetness index; soil pH; bryophyte; lichen; substrate; stand age; plot size; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; ekologisk botanik; Ecological Botany;

   Sammanfattning : The main objectives of this thesis are to study if a topographic wetness index (TWI) could be used as a tool for predicting the spatial distribution of vascular plant species richness in the boreal forest as well as to study congruence in species richness between vascular plants, liverworts, mosses and lichens. A wetness index ln(a/tanβ) based on topography was used to assign a specific TWI-value to every 20 x 20m grid in two 25 km2 boreal forest landscapes (differing in average soil pH) in northern Sweden. LÄS MER

4. 18. Non-indigenous zooplankton : the role of predatory cladocerans and of copepods in trophic dynamics

   Författare :Marc Andersen Borg; Fredrik Wulff; Markku Viitasalo; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Acartia tonsa; Bythotrephes longimanus; Cercopagis pengoi; egg production; fitness; food web changes; ingestion rates; invasive species; metabolic balance; mortality; non-indigenous zooplankton; predation impact; salinity tolerance; stable isotopes; Marine ecology; Marin ekologi; marin ekologi; Marine Ecology;

   Sammanfattning : Human-mediated introductions of non-indigenous species now threaten to homogenize the biota of the Globe, causing huge economic and ecological damage. This thesis studies the ecological role of 3 invasive planktonic crustaceans, the omnivorous copepod Acartia tonsa (western Atlantic and Indo-Pacific) and the predatory cladocerans, Cercopagis pengoi (Ponto-Caspian) and Bythotrephes longimanus (Eurasian). LÄS MER

5. 19. The neglected ecology of the sand goby: Abundance and feeding in the Baltic sublittoral

   Författare :Sigrid Z. Ehrenberg; Ragnar Elmgren; Sture Hansson; Gunilla Ejdung; Erik Bonsdorff; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; sand goby; sublittoral; sub-thermocline; abundance; feeding; consumption; activity; Marine ecology; Marin ekologi; marin ekologi; Marine Ecology;

   Sammanfattning : I investigated the ecology and population density of the sand goby, Pomatoschistus minutus, at sub-thermocline depth in the north-western Baltic proper. Most previous research on the sand goby, and the co-occurring closely related common goby, P. LÄS MER

7. 20. Effects of habitat structure on tropical fish assemblages

   Författare :Kajsa Garpe; Marcus Öhman; Geoffrey Jones; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Marine ecology; Marin ekologi; marin ekologi; Marine Ecology;

   Sammanfattning : Rates of habitat alteration and degradation are increasing worldwide due to anthropogenic influence. On coral reefs, the loss of live coral reduces structural complexity while facilitating algal increase. In many coastal lagoons seagrass and corals are cleared to make room for cultivated macroalgae. LÄS MER