Canopy density heavily affects microclimate conditions within a forest stand and consequently determines local habitat conditions for ectotherm species operating on small scales. Due to the increase in growing stock in Central Europa during the last years, forest species adapted to open canopy conditions are currently more at risk then species adapted to closed canopies. Nowadays natural disturbances and commercial logging affect the canopy density. However, the difference of microclimates between open and closed canopies may be larger than the current observed increase of temperature by global warming. Hence, a better understanding on the mechanisms behind forest species response to microclimates is critical for forest and conservation management.
This proposal aims to study the response of three insect taxa (saproxylic beetles, nocturnal macro-moths and true bugs) to variation in microclimate, controlled for resource availability (plants, deadwood) in a four step approach. First, we analyse a huge dataset from five regions (including the biodiversity exploratories), focusing on the reliable traits body size, wing morphology and colour. Second, we validate our predictions from step one with data acquired in the new forest experiment from the exploratories, in which gaps were created experimentally and were fortified with deadwood systematically. Third, we will investigate the within species response by trait variation to the experimental opening of canopy for selected species occurring in both microhabitats. Fourth, we will perform transcriptome sequencing of four selected species by exposing caged insects to gaps and closed canopy conditions. Our analyses aim to illuminate mechanisms underlying the reactions of insect species and insect compositions in gaps and closed forest patches.
German Research Foundation (433123530)