Search for dissertations about: "introduced species"

Showing result 1 - 5 of 183 swedish dissertations containing the words introduced species.

2. 1. Instrumental and methodological developments for isotope dilution analysis of gaseous mercury species

   Author : Tom Larsson; Erik Björn; Holger Hintelmann; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Mercury; gas; species; speciation analysis; isotope dilution analysis; permeation tubes; Analytical chemistry; Analytisk kemi;

   Abstract : This thesis deals with instrumental and methodological developments for speciation analysis of gaseous mercury (Hg(g)), based on isotope dilution analysis (IDA). The studied species include Hg0, (CH3)2Hg, CH3HgX and HgX2 (where X symbolises a negatively charged counter ion in the form of a halide or hydroxyl ion). READ MORE

4. 2. Biotic resistance in freshwater fish communities

   Author : Anna Henriksson; Göran Englund; David Wardle A.; Jun Yu; Sebastian Diehl; Donald Jackson; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; biotic resistance; freshwater fish; introductions; invasions; invasion success; invasibility; invasiveness; species richness; saturation; species identity; weighted species richness;

   Abstract : Invasions of non-native species cause problems in ecosystems worldwide, and despite the extensive effort that has been put into research about invasions, we still lack a good understanding for why some, but not other, communities resist these invasions. In this doctoral thesis I test hypotheses on biotic resistance using a large dataset of more than 1000 both failed and successful introductions of freshwater fish into Swedish lakes. READ MORE

5. 3. Effects of climate change on boreal wetland and riparian vegetation

   Author : Lotta Ström; Roland Jansson; Christer Nilsson; Sarah Gergel; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; biomass; flooding; hydrologic niche; invasibility; riparian zone; riparian plant species; river margin; climate scenario; seed sowing experiment; species composition; species richness; transplant experiment; Terrestrial ecology; Terrestrisk ekologi;

   Abstract : Models of climate change predict that temperature will increase during the 21th century and the largest warming will take place at high northern latitudes. In addition to warming, predictions for northern Europe include increased annual precipitation and a higher proportion of the precipitation during winter falling as rain instead of snow. READ MORE

6. 4. The threat from non indigenous species - ecosystem vulnerability, global distribution and co-occurrence with other major threats

   Author : Helena Berglund; Biodiversitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; threats; distribution range; isolation; endemism; invasions; invaders; vulnerability; non indigenous species; rarity; threatened species;

   Abstract : We live in a globalised world where people and goods travel large distances. Various species are brought along on these journeys, intentionally or as hitchhikers. Some of these species establish populations in regions to which they could not have spread without human assistance, and where they are considered to be non indigenous species (NIS). READ MORE

7. 5. Introduced and indigenous macroalgae : Ecological effects, functions and regulating factors in tropical seascapes

   Author : Maria Eggertsen; Christina Halling; Charlotte Berkström; Johan Eklöf; Jennifer Smith; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; macroalgae; introduced species; coral-algae interactions; nursery habitats; herbivory; Eucheuma denticulatum; tropical seascape; Marine Ecology; marin ekologi;

   Abstract : Tropical marine shallow-water areas are highly productive systems that promote important ecological functions and biodiversity. Stressors on these systems are intensifying due to increasing anthropogenic disturbances on multiple scales. READ MORE