Search for dissertations about: "Community ecology"

Showing result 21 - 25 of 361 swedish dissertations containing the words Community ecology.

  2. 21. Ecological effects of pesticides in freshwater model ecosystems

    Author : Lina Wendt-Rasch; Biologiska institutionen; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; marine biology; aquatic ecology; limnology; Marinbiologi; Hydrobiology; community; zooplankton; algae; herbicide; insecticide; pesticide mixture; macrophytes; cypermethrin; metsulfuron-methyl; risk assessment; pesticides; microcosms; limnologi; akvatisk ekologi;

    Abstract : In this thesis I have investigated the effects of pesticide exposure on the ecosystem level using various types of experimental ecosystems, i.e. microcosms. The direct effect of exposure to cyperemthrin, a pyretroid insecticide, was a rapid decrease of crustancean zooplankton in enclosures in a lake. READ MORE

  4. 22. Direct and indirect effects of fish predation and excretion in aquatic food webs

    Author : José Luiz Attayde; Biologiska institutionen; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; marine biology; Hydrobiology; zooplankton; resilience; predation; phytoplankton; nutrient enrichment; nutrient recycling; interaction strength; herbivory; food webs; food chain; excretion; fish; detritus; detritivory; aquatic ecology; limnology; Marinbiologi; limnologi; akvatisk ekologi; Ecology; Ekologi;

    Abstract : The aim of this thesis was to elucidate the mechanisms by which planktivorous fish can affect planktonic communities in lakes and how they may affect benthic communities through their effects on planktonic communities. In a laboratory experiment, nutrients released by fish increased algal biomass and altered phytoplankton community structure, suggesting that fish can affect phytoplankton by directly releasing nutrients. READ MORE

  5. 23. Ecology of parasitoids and their hosts in oilseed rape fields

    Author : Josef Berger; Biodiversitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; parasitoids; herbivores; oilseed rape; pollen beetle; cabbage stem weevil; parasitoid community; niche separation; landscape scale; community composition; landscape configuration; Species abundance distribution SAD models; dispersal; metacommunity;

    Abstract : Oilseed rape fields are a very common crop in the agricultural landscape of southern Sweden, and they can harbour surprisingly many insect species. Some of them are herbivores that feed on various parts of the oilseed rape plant, others are natural enemies of the herbivores, and even more species are tourists from the surrounding landscape. READ MORE

  6. 24. Effects of warming on the green alga Cladophora glomerata : Ecological and genetic responses

    Author : Jenny Zie; Pauline Snoeijs; Mats Grahn; Anna Godhe; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; AFLP; Baltic Sea; Cladophora glomerata; climate change; community ecology; genome scan; global warming; selection; Marine Ecology; marin ekologi;

    Abstract : Since the beginning of the 20th century, average global surface temperature has increased ~0.7 °C and the current scenarios predict that it will continue to rise additional 2-4 °C during the 21st century. READ MORE

  7. 25. The aquatic microbial food web and occurence of predation-resistant and potentially pathogenic bacteria, such as Francisella tularensis

    Author : Johanna Thelaus; Agneta Andersson; Mats Forsman; Farooq Azam; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; bacteria; protozoa; ecology; predation; nutrient-availability; microbial food web; model; predation-resistance; Francisella; reservoir; biofilm formation; Freshwater ecology; Limnisk ekologi;

    Abstract : All natural aquatic systems harbour a vast variety of microorganisms. In the aquatic microbial food web, the larger microorganisms (i.e. protozoa) feed on the smaller microorganisms (i. READ MORE