Integrated assessment of regional approaches for biodiversity offsetting in urban-rural areas – A future based case study from Germany using arable land as an example

Abstract

Human interventions, i.e. settlement and construction activities, in the agricultural landscape including farmland but also natural and semi-natural habitats are a major driver of biodiversity loss. Consequently, their impacts on nature and landscape have to be compensated by no net loss policies in many countries around the world. However, their practical implementation often poses challenges with regard to the optimal spatial coordination and assessment of measures, especially in the case of eco-accounts or other habitat banking approaches.Against this backdrop, different approaches to offset biodiversity loss at regional level are analysed with due consideration of indicators of economy, ecology, landscape aesthetics and food production. We used an interdisciplinary modelling approach based on estimates for offsetting demand until 2030. In the integrated land use model, we associated a biophysical crop growth model with an economic optimisation model. The Stuttgart Region – an area with stiff competition amongst anthropogenic land use patterns in Germany – served as the study area. Our main focus was on arable land that has a high potential for nature conservation enhancement. In this context, farmers are deemed to be a major stakeholder group.We observed differing economic and ecological outcomes for the offsetting scenarios we considered. In urban areas with high population density and low biodiversity (e.g. Stuttgart city), compensation close to the site of intervention (on-site) may be more expensive than off-site compensation. However, further added value can be generated by on-site compensation in terms of visual landscape quality enhancement and habitat connectivity, provided that the measures lend themselves to establishing connectivity. Consequently, spatially unrestricted markets for eco credits may exacerbate ecological polarisation between urban and rural areas. Therefore, we concluded that offset site selection should not be driven solely by economics, as this may not optimise overall welfare from a societal perspective, resulting in the need for legal constraints.Our results show the trade-offs between the political goals of spatial planning approaches and compensation strategies. They can, therefore, thus provide valuable information that enables political decision-makers to more clearly weigh up the effects of policy measures in this area.