Sökning: "Systemekologiska institutionen"

Visar resultat 1 - 5 av 60 avhandlingar innehållade orden Systemekologiska institutionen.

1. 1. Living in a predation matrix : Studies on fish and their prey in a Baltic Sea coastal area

   Författare :Ida Ahlbeck; Sture Hansson; Hannu Lehtonen; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; diet analysis methods; Sander lucioperca; behaviour; rearing environment; diel vertical migration; Acartia spp.; Eurytemora affinis; Perca fluviatilis; stable isotopes; body condition; sedentarity; Marine Ecology; marin ekologi;

   Sammanfattning : This thesis was written within the framework of a biomanipulation project where young-of-the-year (YOY) pikeperch (Sander lucioperca) were stocked to a Baltic Sea bay to improve water quality through a top-down trophic cascade. The aim of my doctorial studies was however focused on a broader ecological question, namely predation (the main driving force in a biomanipulation). LÄS MER

3. 2. Filamentous cyanobacteria in the Baltic Sea - spatiotemporal patterns and nitrogen fixation

   Författare :Lisa Almesjö; Ragnar Elmgren; Norbert Wasmund; Stockholms universitet; []
   Nyckelord :Aphanizomenon sp.; Nodularia spumigena; Baltic Sea; image analysis; spatial variability; nitrogen fixation; vertical migration; marin ekologi; Marine Ecology;

   Sammanfattning : Summer blooms of filamentous, diazotrophic cyanobacteria are typical of the Baltic Sea Proper, and are dominated by Aphanizomenon sp. and the toxic Nodularia spumigena. Although occurring every summer, the blooms vary greatly in timing and spatial distribution, making monitoring difficult and imprecise. LÄS MER

4. 3. Round goby Neogobius melanostomus in the Baltic Sea – Invasion Biology in practice

   Författare :Gustaf Almqvist; Magnus Appelberg; Sture (biträdande) Hansson; Johanna Mattila; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Round goby; Neogobius melanostomus; Apollonia melanostoma; non-indigenous fish; life history characteristics; predation; competition; Gulf of Gdańsk; Baltic Sea.; Marine ecology; Marin ekologi; marin- och brackvattensekologi; Marine and Brackish Water Ecology;

   Sammanfattning : Human mediated transfer of non-indigenous species is considered to be a major threat to global biodiversity. The Ponto-Caspian round goby (Neogobius melanostomus), which has established populations in various regions in Eurasia and North-America, was first observed in Gulf of Gdańsk, Baltic Sea, in 1990. LÄS MER

5. 4. 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

7. 5. Managing the Urban Greens : Maintaining ecological functions in human dominated landscapes

   Författare :Erik Andersson; Thomas Elmqvist; Jon Sadler; Stockholms universitet; []
   Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; Natural Resources Management; naturresurshushållning;

   Sammanfattning : At the core of this thesis lie two realisations: First, like other ecosystems, those in urban landscapes provide humans with a number of ecosystem services, some recognized while others are not. Second, in cities just as in other intensively used social-ecological systems, management is of central importance. LÄS MER