Search for dissertations about: "herbivore pressure"

Showing result 1 - 5 of 9 swedish dissertations containing the words herbivore pressure.

2. 1. Ecology and evolution of tolerance in two cruciferous species

   Author : Elin Boalt; Kari Lehtilä; Johan Ehrlén; Julia Koricheva; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; herbivory; tolerance; methodology; Raphanus raphanistrum; Cardamine pratensis; folivory; apex removal; plant competition; ploidy levels; herbivore pressure; Other biology; Övrig biologi; växtekologi; Plant Ecology;

   Abstract : Tolerance to herbivory is the ability of plants to maintain fitness in spite of damage. The goal of this thesis is to investigate the genetic variation and expression of tolerance within species, determine whether and in what conditions tolerance has negative side-effects, and how tolerance is affected by different ecological factors. READ MORE

4. 2. Plant-soil-herbivore interactions in a high Arctic wetland - Feedbacks to the carbon cycle

   Author : Julie Maria Falk; Institutionen för naturgeografi och ekosystemvetenskap; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Arctic wetlands; carbon balance; herbivory; increased grazing pressure; methane fluxes; muskox exclusion; substrate avalibility; vegetation composition and density;

   Abstract : Arctic ecosystems hold massive amounts of the global carbon in their soils and are of great importance for the global terrestrial exchange of greenhouse gases to the atmosphere. The arctic region has in general been acting as a C sink for the past 10000 years, however with climate change the C balance in some areas is shifting towards becoming a C source. READ MORE

5. 3. Ecology and evolution in a host-parasitoid system : Host search, immune responses and parasitoid virulence

   Author : Lisa Fors; Peter Hambäck; Wertheim Bregje; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Host-parasitoid interactions; Plant-herbivore interactions; Host search; Volatiles; Pheromones; Geographic variation; Cellular defence; Melanisation; Encapsulation; Asecodes; Galerucella; Plant Ecology; växtekologi;

   Abstract : In host-parasitoid systems, there is a continuous coevolutionary arms race where each species imposes a strong selection pressure on the other. The host needs to develop defence strategies in order to escape parasitism and the parasitoid must evolve counter-defence strategies in order to overcome the host’s immune defence and successfully reproduce. READ MORE

6. 4. Marine seaweed invasions : Impacts and biotic resistance in native ecosystems

   Author : Josefin Sagerman; Sofia Wikström; Fransisco Arenas; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Plant invasion; exotic species; generalist herbivores; plant-herbivore interactions; enemy-release hypothesis; ecosystem function; marin ekotoxikologi; Marine Ecotoxicology;

   Abstract : Marine seaweeds constitute one of the most productive plant systems known on Earth and a rich fauna including juvenile fish and crustaceans is dependent on the habitats they form. Human influence on marine costal ecosystems has resulted in large scale changes to the abundance and distribution of species, where species introductions constitute an obvious part. READ MORE

7. 5. The role of herbivores in mediating responses of tundra ecosystems to climate change

   Author : Elina Kaarlejärvi; Johan Olofsson; Anu Eskelinen; Jon Moen; Eric Post; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Climate change; warming; grazer; Rangifer; Lemmus lemmus; species distribution; biotic interactions; altitude; Environmental Science; miljövetenskap;

   Abstract : The Arctic areas are warming more rapidly than other parts of the world. Increasing temperatures are predicted to result in shrubification, higher productivity, declining species diversity and new species invasions to the tundra. READ MORE