Effects of grazing removal on ɑ-diversity of plant and soil
communities.
For the analysis of changes in diversity, we used a total of 113 mite
and 79 springtail phylotypes, 30 nematode taxa (families/genera), 2068
protist phylotypes, and 2179 fungal and 10336 bacterial phylotypes.
Aboveground we recorded 76 species of vascular plants. Estimated species
richness levels (as a measure of ɑ-diversity) of soil eukaryotes, soil
fauna and vascular plants were consistently reduced as a result of
grazing removal (Figure 3). This decline was most pronounced for
vascular plants, which declined from an average of 8.0 species in
managed plots to 5.8 species (response ratio: -0.57) in grazing removal
plots (F(1,74) 14.2, p < 0.001; Figure 3).
Nematode richness decreased with grazing removal, as illustrated by the
negative response ratio of -0.27 (F(1, 71) 19.4,
p<0.001; Figure 3); species richness of mites and springtails
showed a similar, but non-significant trend. Within the microbes,
species richness of microbial eukaryotes declined with grazing removal:
the phylotype richness of fungi decreased by 19% in the grazing removal
treatment (response ratio -0.29, F(1, 72) 13.6,
p<0.001; Figure 3) and the phylotype richness of protists
decreased by 17% (response ratio -0.21, F(1, 72) 9.8,
p=0.003). In contrast, phylotype richness of bacteria did not show a
significant response to grazing removal (0.4% change; Figure 3).