Phylogenetic relatedness to native congeners drives insect abundance and diversity hosted by non-native trees

Non-native trees are of major importance in forestry and urban greening but are controversially discussed with regard to their effects on native biodiversity. Existing literature reports positive as well as negative biodiversity effects of non-native trees. Geographic, climatic and phylogenetic distance between the non-native and native tree species are named as important factors shaping these biodiversity effects. However, studies with a large geographic and taxonomic coverage are missing. Here we tested the effects of geographic, climatic and phylogenetic distance on resident insect abundance and diversity for 77 native and non-native tree species in a common garden trial. We identified phylogenetic distance of tree species to be the main driver of insect abundance and diversity with a negative effect of increasing phylogenetic distance and stronger effects for phytophagous than for non-phytophagous insects. This highlights the necessity to account for phylogenetic history shared between native and non-native congeners when managing non-native trees.