RT Journal Article
SR Electronic
T1 Spatial scale influence the associational effects of neighbor plants on mammal herbivory. Insights from a meta-analysis
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 019935
DO 10.1101/019935
A1 Emilie Champagne
A1 Jean-Pierre Tremblay
A1 Steeve D. Côté
YR 2015
UL http://biorxiv.org/content/early/2015/05/28/019935.abstract
AB There is high intra-specific variability in susceptibility of plants to herbivores with potential effects on the population dynamics of species, community composition, structure and function. This variability can be partly explained by vegetation assemblages, i.e. associational effects yet, it is still unclear how the spatial scale of plant associations modulates foraging choice of animal; an inherently spatial process in itself. Using a meta-analysis, we investigated how spatial scale modifies associational effects of neighboring plants on the susceptibility to deer-sized herbivores. From 2496 articles found in main literature databases, we selected 46 studies providing a total of 168 differences of means in damage or survival with and without neighboring plants. We tested the impact of spatial scale, estimated as the distance between the focal plant and its neighbors, and the type of associational on the effect sizes reported in these studies using a meta-analysis mixed model. The strength of associational effects slightly increases between 0 and 1 m and decrease at scales larger than 1 m. Associational defence (i.e. decrease in susceptibility with repulsive neighbors) had stronger effects than any other type of associational effects, but was not more frequent. Our study is the first addressing the magnitude of change in associational effects with spatial scale. Further empirical studies should test associational effects between plants at multiple spatial scales simultaneously. The high remaining heterogeneity between the studies suggests that untested factors modulate associational effects, such as nutritional quality of focal and neighboring plants or timing of browsing. Associational effects can be exploited as a management tool to alleviate the effect of herbivores (e.g. planting susceptible plants under nurse species) so understanding these intratrophic relationships shaping multitrophic interactions could improve the utility of the tool.