Complex vegetation responses to soil disturbances in mountain grassland |
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Authors: | Maria-Teresa Sebastià Laura Puig |
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Institution: | (1) Forest Technology Centre of Catalonia, Pujada del Seminari s/n, 25280 Solsona, Spain;(2) Agronomical Engineering School, University of Lleida, Av. Rovira Roure 191, 25198 Lleida, Spain |
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Abstract: | We studied vegetation responses to disturbances originated by ants and voles in subalpine grasslands in the Eastern Pyrenees.
We compared the effects of these small-scale disturbances with those of a large-scale disturbance caused by ploughing. We
wanted to know if these soil disturbances promoted species richness through the existence of a specific guild of plants colonizing
these areas, and if this guild was the same for all soil disturbances, independently of their extent. In general, grassland
vegetation seemed to recover relatively quickly from soil-displacement disturbances, and the effects could be scaled up in
time and space in terms of species richness and composition. Vole mound composition was similar to that in the surrounding
grassland, suggesting that mounds were rapidly colonized by the neighbouring vegetation. Vegetation composition differed between
the grassland and the ant mounds. Grasses and erect dicots coped well with repeated disturbance, while rosette-forming species
and sedges were very sensitive to it. Landscape processes could be important to understanding recolonization. Species from
xeric grasslands were found in mesic grasslands when disturbed by ploughing and on the tops of active ant mounds. Furrows
in mesic grasslands recovered well, but decades after disturbance showed long persistence of some xeric species and increased
species richness compared to terraces, while xeric grasslands showed decreased richness. This suggests that, because of those
disturbances, within-habitat diversity was increased, although landscape diversity was not. However, specific disturbances
showed idiosyncratic effects, which could enhance the species richness globally. In ant-affected areas, the grassland itself
showed the highest plant species richness, partially associated to the presence of some species with elaiosomes not, or only
rarely, found in adjacent grasslands without ant mounds. Therefore, soil disturbances occurring at different spatial scales
contributed to complexity in vegetation patterns in addition to abiotic factors and grazing.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Nomenclature of the species follows Tutin et al. (1964–1980) and Bolòs et al. (1993). |
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Keywords: | Ant hill Plant functional types Plant species richness Ploughing Pyrenees Vole mound |
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