From leaf litter to crowns: Response of animal biodiversity to native and non-native oak vegetation

Abstract

The change in tree species composition is an important process influencing forest biodiversity worldwide. Therefore, it is important to reveal its actual impacts on forest biodiversity. We selected three animal groups (birds, beetles and soil macroinvertebrates) with different dispersal abilities to answer the following scientific question: how does the replacement of a native tree species, pedunculate oak (Quercus robur), by the non-native red oak (Q. rubra) affect the species richness and compositions of the analyzed animal groups?We selected ten lowland woodlands surrounding the city of Pardubice (Czech Republic). In total, forty patches with twenty in mature native oak and twenty in mature non-native oak were studied in the 2017 vegetation season.We found that the effect of the tree species on the species richness was mainly negative for both oak species. The samples with the highest species richness coincided with stands containing mixed native and non-native oak trees. The species composition results indicated that several species avoided red oak, but highly similar numbers of species indicated the same avoidance of the native oak.The results of our study revealed that the effect of non-native vegetation was not as profound as expected, compared to the effect of native vegetation. Neither native nor non-native vegetation significantly affected even flightless fauna. Nevertheless, the extensive planting of non-native trees is not advantageous for many known reasons (e.g., invasibility). An important approach when using non-native trees like red oak in forests is to plant these species admixed or interspersed. In these cases, the impacts of non-native species on the biota are not necessarily negative.