Willem Proesmans

Does neighbourhood tree diversity affect the crown arthropod community in saplings

Mixed forest with multiple tree species is expected to create heterogeneous habitat and diverse niches for the canopy arthropod community. We assessed arthropod abundance, order richness, and community composition in the crowns of saplings of nine temperate tree species in two plantations of a recently established tree diversity experiment in Belgium, and looked for relationships with the diversity and structure of the sapling’s local neighbourhood. The crown arthropod community differed between the two study sites, both in terms of abundances and composition. More arthropods were found in the post-agricultural site; the arthropod community was more complex in the formerly forested site. The tree species identity of a sapling, its apparency, and the phylogenetic diversity of its local neighbourhood all affected the crown arthropod community. Our study suggests that mixing phylogenetically distant tree species creates niches for a complex crown arthropod community.

Linking macrodetritivore distribution to desiccation resistance in small forest fragments embedded in agricultural landscapes in Europe

PurposeMost of the agricultural landscape in Europe, and elsewhere, consists of mosaics with scattered fragments of semi-natural habitat like small forest fragments. Mutual interactions between forest fragments and agricultural areas influence ecosystem processes such as nutrient cycling, a process strongly mediated by the macrodetritivore community, which is however, poorly studied. We investigated macrodetritivore distribution patterns at local and landscape-level and used a key functional trait (desiccation resistance) to gain mechanistic insights of the putative drivers.MethodsMacrodetritivores were sampled in forest edges-centres of 224 European forest fragments across 14 landscapes opposing in land use intensity. We used a multilevel analysis of variance to assess the relative contribution of different spatial scales in explaining activity-density and Shannon-diversity of woodlice and millipedes, together with a model-based analysis of the multivariate activity-density data testing the effect on species composition. Secondly, we tested if desiccation resistance of macrodetritivores varied across communities at different spatial scales using linear mixed effect models.ResultsForest edge-centre and landscape use intensity determined activity-density and community composition of macrodetritivores in forest fragments, while fragment characteristics like size and continuity were relatively unimportant. Forest edges and higher intensity landscapes supported higher activity-density of macrodetritivores and determined species composition. Forest edges sustained woodlouse communities dominated by more drought tolerant species.ConclusionsLandscape use intensity and forest edges are main drivers in macrodetritivore distribution in forest fragments with desiccation resistance a good predictor of macrodetritivore distribution. Key functional traits can help us to predict changes in community structure in changing landscapes.