Tree diversity improves forest resistance to insect defoliators

摘要: Whether increasing forest diversity should result in less insect damage (Associational Resistance, AR) or more Susceptibility, AS) is still debated. Moreover little known about - resistance relationships mature forests due to methodological constraints. To address this question we used the FundivEurope exploratory platform. In network of 209 plots, sampled along two orthogonal gradients tree species richness (from one five mixtures) and latitude (spanning from Mediterranean boreal biomes), assessed defoliation crown. Focusing on eleven broadleaved species, could for first time demonstrate a global pattern reduced (AR) across Europe. We replicated comparison herbivory pure vs. mixed plots oak trees, at edge within patches. Here found again significantly oaks surrounded by heterospecific neighbors, showed that magnitude AR was larger than interiors. Last tested hypothesis with an invasive alien Asian chestnut gall wasp, Italy. Based same approach, our study significant decrease stands. Our work therefore provides new experimental evidence supporting Associational Resistance three original contributions: i) does apply forests, ii) irrespective identity herbivores, iii) including pest species. These findings may have important implications management maintenance improvement being promising tool preventing damage.