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Effects of grazing exclusion on the spatial variability of subalpine plant communities: a multiscale approach

Authors :
Grégory Loucougaray
Didier Alard
Claire Deléglise
Ecosystèmes montagnards (UR EMGR)
Centre national du machinisme agricole, du génie rural, des eaux et forêts (CEMAGREF)
Université de Bordeaux (UB)
Source :
Basic and Applied Ecology, Basic and Applied Ecology, Elsevier, 2011, 12 (7), pp.609-619. ⟨10.1016/j.baae.2011.08.006⟩
Publication Year :
2011
Publisher :
HAL CCSD, 2011.

Abstract

International audience; The fine-scale spatial structure of plant communities is a key component for understanding the dynamics in vegetation following changes in land management but needs to be assessed at an appropriate scale. We studied the response of plant diversity and spatial variability of species and trait composition to grazing vs. non-grazing (>20 years) using different grain sizes of sampling in three subalpine plant communities. Species composition, diversity, and the aggregated values of 4 leaf traits were assessed at 7 grain sizes (within quadrats ranging from 25 cm2 to 1 m2) in 9 grazed and ungrazed paired plots. Evenness and species richness showed a strongly community-dependent response as they increased following grazing exclusion in the less productive community and decreased in the two more productive ones. Although species richness was influenced by grazing exclusion at grains larger than 625 cm2, evenness was affected at the finest grain investigated (25 cm2). In contrast, spatial variability of species composition was similarly affected across the three plant communities and increased following grazing exclusion from the 100 cm2-grain size. Grazing led to a sharper decline of spatial variability with increasing quadrat size revealing that the grain of spatial heterogeneity was finer in grazed plots relative to that in ungrazed ones. The response of spatial variability of aggregated trait values was less consistent, possibly because of functional redundancy between species. However, grazing exclusion increased the spatial variability of the aggregated values of leaf dry matter content and leaf carbon and nitrogen content. We suggest that spatial variability of species composition could be useful for detecting within-community changes in response to grazing management as it was detectable using a very fine scale of sampling and responded similarly to grazing treatment in every community. Such spatial variability in species composition can induce spatial organization of plant traits that may be important for community functioning.

Details

Language :
English
ISSN :
14391791
Database :
OpenAIRE
Journal :
Basic and Applied Ecology, Basic and Applied Ecology, Elsevier, 2011, 12 (7), pp.609-619. ⟨10.1016/j.baae.2011.08.006⟩
Accession number :
edsair.doi.dedup.....cb859903af4bac56995de88522b89474
Full Text :
https://doi.org/10.1016/j.baae.2011.08.006⟩