Functional and phylogenetic diversity of woody plants drive herbivory in a highly diverse forest

Abstract

Biodiversity loss may alter ecosystem processes, such as herbivory, a key driver of ecological functions in species-rich (sub)tropical forests. However, the mechanisms underlying such biodiversity effects remain poorly explored, as mostly effects of species richness – a very basic biodiversity measure – have been studied. Here, we analyze to what extent the functional and phylogenetic diversity of woody plant communities affect herbivory along a diversity gradient in a subtropical forest.We assessed the relative effects of morphological and chemical leaf traits and of plant phylogenetic diversity on individual-level variation in herbivory of dominant woody plant species across 27 forest stands in south-east China.Individual-level variation in herbivory was best explained by multivariate, community-level diversity of leaf chemical traits, in combination with community-weighted means of single traits and species-specific phylodiversity measures. These findings deviate from those based solely on trait variation within individual species.Our results indicate a strong impact of generalist herbivores and highlight the need to assess food-web specialization to determine the direction of biodiversity effects. With increasing plant species loss, but particularly with the concomitant loss of functional and phylogenetic diversity in these forests, the impact of herbivores will probably decrease – with consequences for the herbivore-mediated regulation of ecosystem functions.

Early positive effects of tree species richness on herbivory in a large‐scale forest biodiversity experiment influence tree growth

“…Many grasshoppers have a relatively broad host plant spectrum (Bernays & Chapman ), and the same probably applies to dominant caterpillars in our study region (see Schuldt et al . ,b). Increases in the abundance (e.g.…”

“…Schuldt et al . ) and herbivory might thus not only respond to, but actively influence assembly processes of tree communities.…”

Background losses of woody plant foliage to insects show variable relationships with plant functional traits across the globe

“…; Schuldt et al . ), and no general pattern has emerged. A higher herbivory was reported on woody plants with larger species‐specific leaf size (Cárdenas et al .…”

Positive interactions between herbivores and plant diversity shape forest regeneration

“…First, that plant performance would increase with diversity [3] and decrease with browsing [21,25,26], but that this diversity-performance link would be altered by deer. In particular, we predicted that palatable species might show the greatest performance increase in polycultures because unpalatable species might buffer palatable neighbours from attack [23,27,28]. We also predicted that decreasing intraspecific plant density would reduce both herbivore attack rates and intraspecific competition [20].…”