Intraspecific herbivory variability, rather than species' turnover,
drives latitudinal patterns in community-wide herbivory
Abstract
Attempts over the past 30 years to explain geographic variation in the
strength of herbivore pressure gave rise to the latitudinal herbivory
hypothesis. However, this long-standing hypothesis has rarely been
tested using community-level data. In this study, we selected 43
grassland sites along a 1,500-km latitudinal gradient (c. 27°N to 39°N)
on the Qinghai-Tibetan Plateau. We calculated community-wide herbivory
at each site by summing herbivory across plant species weighted by the
biomass of each species; we then investigated how abiotic and biotic
latitudinal correlates drove community-wide herbivory via their effects
on intraspecific herbivory variability and species’ turnover. We found
that community-wide herbivory decreased with latitude, mirroring
intraspecific herbivory variability. Furthermore, intraspecific
herbivory variability was driven by climatic factors, but not edaphic or
plant community factors. Overall, our study highlights the importance of
considering both intraspecific herbivory variability and species’
turnover for predicting how climate change will alter community-wide
herbivory.