Search for dissertations about: "ecosystem engineers"

Showing result 1 - 5 of 7 swedish dissertations containing the words ecosystem engineers.

2. 1. The zoo-geomorphological impact of fossorial rodents in sub-polar alpine environments

   Author : Bert Eriksson; Jan Boelhowers; John Östh; Hanna Ridefelt; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; zoo-geomorphology; fossorial rodents; sub-polar; alpine; geomorphic work; ecosystem engineers; Physical geography; Naturgeografi; Geography; Geografi;

   Abstract : The geomorphological impact of small fossorial mammals (adapted to digging and living underground), such as rodents can be significant, and both their direct and indirect effects may contribute to landscape formation. This thesis is based on empirical field studies of two burrowing rodent species in sub-polar environments, namely invasive House mice (Mus musculus) on sub-Antarctic Marion Island and Norwegian lemmings (Lemmus lemmus) in sub-Arctic Abisko. READ MORE

4. 2. Megaherbivores and Earth system functioning: Landscape-scale effects of white rhino loss on vegetation, fire and soil carbon dynamics

   Author : Olli Hyvärinen; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES;

   Abstract : Megaherbivores (> 1000 kg) have been suggested to strongly influence ecosystem functioning with consequences potentially scaling up to the global climate. However, due to poaching, we may lose some of the most vulnerable species at functional densities in the wild in the coming decades. READ MORE

5. 3. Responses of peatland vegetation to enhanced nitrogen

   Author : Magdalena Wiedermann; Lars Ericson; Juul Limpens; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Sphagnum; nitrogen; peatlands; soluble amino acids; gradient study; field experiment; Biology; Biologi;

   Abstract : Human alteration of the global nitrogen (N) cycle has had major impacts on naturally N-limited ecosystems worldwide. Peatlands, dominated by peat mosses, Sphagnum species, represent one such sensitive ecosystem. READ MORE

6. 4. Functional Traits in Sphagnum

   Author : Fia Bengtsson; Håkan Rydin; Gustaf Granath; Cronberg Nils; Sari Juutinen; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; peat mosses; functional traits; NPP; decay resistance; N2 fixation; desiccation resistance; climate; Biology with specialization in Ecological Botany; Biologi med inriktning mot ekologisk botanik;

   Abstract : Peat mosses (Sphagnum) are ecosystem engineers that largely govern carbon sequestration in northern hemisphere peatlands. I investigated functional traits in Sphagnum species and addressed the questions: (I) Are growth, photosynthesis and decomposition and the trade-offs between these traits related to habitat or phylogeny?, (II) Which are the determinants of decomposition and are there trade-offs between metabolites that affect decomposition?, (III) How do macro-climate and local environment determine growth in Sphagnum across the Holarctic?, (IV) How does N2 fixation vary among different species and habitats?, (V) How do species from different microtopographic niches avoid or tolerate desiccation, and are leaf and structural traits adaptations to growth high above the water table?Photosynthetic rate and decomposition in laboratory conditions (innate growth and decay resistance) were related to growth and decomposition in their natural habitats. READ MORE

7. 5. Ecological and biogeochemical implications of the recovery of Eurasian beavers

   Author : Oded Levanoni; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES;

   Abstract : In pre-industrial times beavers, ecosystem engineers, inhabited most of the Holarctic. Intensive exploitation over the last millennium, particularly in Europe during the 18th and 19th centuries, led to a dramatic decline in beaver populations. READ MORE