Invertebrate species distributions in urban ecosystems are driven by habitat availability, not by anthropogenic drivers

Rapid urbanisation puts pressure on biodiversity by habitat fragmentation and habitat quality among others. These habitat changes are known to affect species dispersal and connectivity and ultimately species distribution in many ecosystems. However, little is known about the changing urban species distributions which in turn influence community assembly. New DNA-based sampling methods combined with species distribution modelling provide a way to quantitatively estimate urban community assembly through assessing many species distributions and their drivers simultaneously.

We investigated species distributions of entire communities in the city of The Hague (the Netherlands) by sampling DNA with two distinct methods: collecting data on invertebrate occurrence with traditional trapping (bulk; n = 205) and a novel Environmental DNA method (eDNA; n = 207). After DNA sequencing, species were identified using Operational Taxonomic Units. Subsequently, individual species presence and absence were used in Species Distribution Models (SDMs), based on spatial information on vegetation and anthropogenic influences.

The results show a difference in coverage of sampling methods (bulk vs. eDNA), indicating their complementary information. The models on species distributions were generally significantly better than random models (59.5%), and performed well during calibration (90.4%, AUC > 0.70). In contrast, during validation very few SDMs (1.3%, AUC > 0.70) performed adequately in predicting species distributions.

Through this novel combination of DNA sampling with SDMs we show that density and structure of vegetation, as well as distance to water are more important for urban invertebrate distribution than direct anthropogenic pressures. This suggests that dispersal is not a limiting factor in The Hague’s urban environment. The availability of a variety of urban green infrastructures seems sufficient to attract many of the species observed. Hence, ensuring sufficient green infrastructure in the urban environment should be the first priority to enhance biodiversity in the urban environment.

Highlights

• Vegetation and water indicators are the most important predictors for accurate assessment of species’ distribution

• Anthropogenic pressures have lower impact on urban species distributions

• DNA-SDM combinations show potential in guiding urban planners in evidence-based decision making