Response to reindeer grazing removal depends on soil characteristics in low Arctic meadows

In Arctic tundra, grazing is expected to exert a positive influence on microbial activity thus enhancing nutrient cycling and promoting the presence of high productive graminoids. We investigated the changes occurring in two low Arctic meadow sites after 10 years exclusion from grazing. We compared plant, soil fauna and microbial community composition, extracellular enzymes activities, and soil nutrients in ungrazed and adjacent grazed area in two low Arctic meadows. The two closely located experimental sites were both dominated by the common grass Deschampsia flexuosa which covered more than 50% of the meadows. Plant community was affected significantly by site and grazing, but the effect of grazing was stronger in the site that was more nutrient rich. Grazing decreased litter abundance in both sites, but did not influence the amount of total plant biomass. Grazing had a negative effect on some species of Collembola (e.g. Isotomiella minor) and Enchytraeidae were reduced by 40% by grazing. Also the site itself contributed in shaping the microarthropod community. Microbial community structure was not affected by grazing. In the nutrient rich site grazing also significantly decreased some extracellular enzyme activities. Our results showed that grazing had a strong effect on plant and microarthropod community structure, but the effects were very dependent on local characteristics. (C) 2013 Elsevier B.V. All rights reserved.