Maintaining habitat connectivity in an urbanising world: understanding interactions in large-scale coupled habitat and settlement networks

Abstract

For their survival, animal species depend on networks of well-connected habitat patches (i.e. habitat networks). Likewise, the well-being and economic prosperity of many human societies depend on networks of settlements that are well-connected by roads and traffic (i.e. settlement networks). In many regions across the world, settlement networks are densifying and expanding due to a rapidly growing and urbanising human population. Such changes to settlement networks often lead to decreases in habitat size, quality and/or connectivity, thereby diminishing the integrity of habitat networks and ultimately the survival of species. However, interacting processes within settlement networks (e.g. settlement growth can increase traffic flows and vice versa) make it difficult to predict how changes in a region's settlement network will affect its habitat networks. Nevertheless, such knowledge is essential for conservation, landscape and transport planning to simultaneously ensure human well-being and the protection of biodiversity. Such knowledge can be derived from models that simulate the dynamics within and between settlement and habitat networks at regional or national scales. Yet, most urban and road ecology studies focus at smaller scales and on specific types of human-animal interactions and to date such large-scale, integrated models have not been developed. Here we present results from a research project (CHECNET: coupling human and ecological networks for sustainable landscape and transport planning) aimed at understanding trade-offs and synergies in coupled habitat and settlement networks. With simple simulations studies in hypothetical landscapes, we have previously shown that the configuration of roads and settlements can have significant effects on habitat connectivity [1]. We now focus on empirically derived settlement and habitat networks in the Swiss plateau (i.e. a densely populated region in Switzerland). Large-scale habitat networks for a range of amphibian species are constructed with an innovative approach making use of readily available animal occurrence data (programmed in R and Python). These habitat networks are then coupled to a dynamic settlement network, which is simulated with a Swiss-wide land-use transport interaction model (FaLC, [2]). With this model, changes in settlement size and traffic flows can be predicted under a range of policy and socio-economic scenarios. We present the interactions that we found between these networks and their implications for conservation planning. Our results underline the importance of considering the interactions in large-scale habitat and settlement networks in order to maintain habitat connectivity in an urbanising world.

References

1. Van Strien MJ and A Grêt-Regamey (2016) Ecological Modelling 342: 186-198

2. Bodenmann BR, et al. (2014) FaLC land-use and transport interaction model for Switzerland: first results. 14th Swiss Transport Research Conference, Ascona, Switzerland