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

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.

Schuldt A ，Assmann T ，Bruelheide H ，Durka W ，Eichenberg D ，Härdtle W ，Kröber W ，Michalski SG ，Purschke O ... -  《-》

Tree diversity promotes generalist herbivore community patterns in a young subtropical forest experiment.

Zhang J ，Bruelheide H ，Chen X ，Eichenberg D ，Kröber W ，Xu X ，Xu L ，Schuldt A ... -  《-》

Woody plant phylogenetic diversity mediates bottom-up control of arthropod biomass in species-rich forests.

Schuldt A ，Baruffol M ，Bruelheide H ，Chen S ，Chi X ，Wall M ，Assmann T ... -  《-》

Forest diversity effects on insect herbivores: do leaf traits matter?

Insect herbivore damage and abundance are often reduced in diverse plant stands. However, few studies have explored whether this phenomenon is a result of plant diversity effects on host plant traits. We explored indirect effects of tree species diversity on herbivory via changes in leaf traits in a long-term forest diversity experiment in Finland. We measured 16 leaf traits and leaf damage by four insect guilds (chewers, gall formers, leaf miners and rollers) on silver birch (Betula pendula) trees growing in one-, two-, three- and five-species mixtures. A decline in the frequency of birch in mixed stands resulted in reduced leaf area. This, in turn, mediated the reduction in chewing damage in mixed stands. In contrast, associational resistance of birch to leaf miners was not trait-mediated but driven directly by concurrent declines in birch frequency as tree species richness increased. Our results show that leaf trait variation across the diversity gradient might promote associational resistance, but these patterns are driven by an increase in the relative abundance of heterospecifics rather than by tree species richness per se. Therefore, accounting for concurrent changes in stand structure and key foliar traits is important for the interpretation of plant diversity effects and predictions of associational patterns.

Muiruri EW ，Barantal S ，Iason GR ，Salminen JP ，Perez-Fernandez E ，Koricheva J ... -  《-》

Tree diversity promotes insect herbivory in subtropical forests of south-east China.

Schuldt A ，Baruffol M ，Böhnke M ，Bruelheide H ，Härdtle W ，Lang AC ，Nadrowski K ，von Oheimb G ，Voigt W ，Zhou H ，Assmann T ，Fridley J ... -  《-》