Andean grassland stability across spatial scales increases with camelid grazing intensity despite biotic homogenization

Intensive land use and changing environmental conditions are reshaping the
biodiversity, functioning and stability of local Andean grassland
communities. It remains unclear whether these effects propagate to larger
spatial scales that are most relevant for policy and conservation. Using a
multiscale framework, we quantified the influence of grazing intensity and
environmental factors on the diversity and temporal stability of
productivity in Andean grassland plant communities at both the local
(within communities) and larger (among neighboring communities) spatial
scales. We found that higher grazing intensity and soil total nitrogen
were related to greater stability at both the local (alpha stability) and
larger (gamma stability) scales. Higher gamma stability at higher grazing
intensity resulted from enhanced spatial asynchrony of productivity among
communities despite biotic homogenization. That is, while higher grazing
intensity reduced compositional differences among communities (beta
diversity) which in turn decreased spatial asynchrony, this indirect
effect was not strong enough to counteract the direct positive influence
of grazing on spatial asynchrony and gamma stability. Additionally, local
diversity (alpha diversity) decreased with increasing soil acidification
but did not influence alpha or gamma stability. Synthesis: Our results
emphasize the necessity of considering the complex influences of grazing
intensity on diversity and stability at different spatial scales for the
effective management of Andean grasslands.