Vinsamlegast notið þetta auðkenni þegar þið vitnið til verksins eða tengið í það: http://hdl.handle.net/1946/15502
Land degradation is one of the major environmental issues of the 21st century, caused mainly by overgrazing, agricultural practices and deforestation that often lead to soil erosion. Soil erosion results in the loss of soil nutrients and water holding capacities and in decreasing biodiversity and maintenance of soil erosion. These cycles can be reversed by adding nutrients to the soil and re-establishing vegetation.
About 40% of Iceland is severely eroded and soil- and vegetation conservation is a priority. Vegetation reclamation supports vegetation succession and restoration of biodiversity. The abundance and communities of animals, like birds and invertebrates, are strongly linked to vegetation succession and reflect reclamation success. In this large-scale study, animal biodiversity was linked to vegetation types at different stages of succession in the vicinity of Mt. Hekla which is one of the most severely eroded areas in Iceland. The study area, which covers 1% of Iceland is under great impact from the very active Hekla volcano and is a venue for a large scale birch woodland restoration program (Hekluskógar).
The aim of the study was to explore the links between animal biodiversity and erosion/succession patterns which are poorly known in Iceland and to serve as yardstick on which to estimate the effect of restoration efforts and volcanism in the area.
Birds were counted on transects in total of 59 study sites in 6 habitat types, at different stages of vegetation succession (barren land, moss, grassland, heathland, wetland and tall vegetation) and invertebrates were caught in pitfall traps in 36 sites. Density and communities of birds and the abundance, diversity and biomass of invertebrates were estimated.
The density of birds increased with vegetation succession, from 22.6 birds/km2 (SE= 11.3) on barren land to 201.3 birds/km2 (SE= 106.4) on wetland. Invertebrates catches varied from 6.4 animals/trap/day (SE= 0.83) on barren land to 19.5 animals/trap/day (SE= 2.32) in grassland. Bird diversity was lowest in barren land and highest in wetland but invertebrate diversity was lowest in moss and highest in tall vegetation. Invertebrate biomass was on the other hand lowest in barren land (2.99 mg/trap/day, SE= 1.25) but highest in wetland. (23.1 mg/trap/day, SE= 9.74). In all, wetland supported the most animal density and diversity, although habitats overlapped to some extent. Although there was a relatively high variation in measurements within habitats, the study showed a clear general increase the abundance and diversity of birds and invertebrates with increasing vegetation cover and succession.
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