Data from: Foraging responses of sheep to plant spatial micro-patterns can cause diverse associational effects of focal plant at individual and population levels

1. Multiple-scale foraging decisions by large herbivores can cause
associational effects of focal plant individuals neighbored with different
species. Spatial micro-patterns between the focal plant and its
neighboring species within patches can affect herbivore foraging
selectivity at within- and between-patch scale, which may consequently
lead to associational plant effects occurring at both plant individual and
population levels. However, these associational effects have not been
explored together in the plant-herbivore interaction studies. 2. We aim to
evaluate how plant spatial micro-pattern within different quality patches
mediate herbivore foraging selectivity, thereby affecting the
associational effects of focal plant individuals and population. 3. Using
sheep as the model herbivore and a medium preferred species as the focal
plant, we conducted a manipulative experiment by allowing sheep grazing
freely among three different quality patches, each of which consisted of
preferred, un-preferred and focal plant species with different abundances
forming spatially aggregated or dispersed micro-patterns. 4. Results
showed that, compared with the aggregated plant micro-pattern, dispersed
plant micro-patterns within different quality patches increased sheep
within-patch selectivity, and caused diverse associational effects of
focal plant individuals. Focal plant individuals experienced neighbor
contrast defense (i.e. got protection in the high quality patch) and
associational defense (i.e. got protection in the low quality patch),
respectively, when plants dispersedly distributed in the low and high
quality patch. Focal plant individuals simultaneously experienced
associational susceptibility (i.e. got damage in the high quality patch)
and neighbor contrast susceptibility (i.e. got damage in the low quality
patch) when plants dispersedly distributed in the medium quality patch.
Furthermore, dispersed plant micro-patterns reduced sheep foraging
selectivity between patches, and led to a lower consumption of focal plant
population compared with the aggregated plant micro-pattern. 5. Herbivore
adopt different within- and between-patch foraging decisions to maintain a
high intake of the preferred species in response to various plant
micro-patterns, and consequently cause diverse associational effects of
both focal plant individuals and population. These associational effects
have important implications for understanding the species coexistence and
plant community assembly in the grazing ecosystems.