Simulating small woody feature restoration to enhance habitat connectivity in intensively farmed areas of the European Union

Widespread conversion of land to intensive agriculture across Europe has led to a significant decrease in the availability of natural habitat. Besides direct local effects, this process also disrupts connectivity between shrinking habitat patches. This pattern has ignited various, self-reinforcing ecological mechanisms that are threatening the resilience of natural communities and the ecosystem services they provide. In response, the European Union (EU) has been promoting policies to increase the availability of natural habitats with minimal impacts on agricultural yields. For instance, the EU Biodiversity Strategy 2030 set a target of incorporating high diversity landscape features into 10% of agricultural land.. In this study, we explore potential ecological benefits of habitat connectivity enhancement—stemming from the expansion of “Small Woody Features” (SWF); woody habitats within the agricultural matrix of the most densely cultivated areas (i.e., crop areas >90%). Using a spatially explicit algorithm and data from farmers’ declarations, we simulated plausible scenarios of progressive expansion of SWF following alternative sets of spatial rules. To compare the ecological outcomes of different scenarios, we focused on a single metric of connectivity, the Equivalent Connected Area, which we measured at each step of our SWF expansion simulations. We found that expanding SWF along the existing boundaries of agricultural field parcels maximises gains in connectivity. Our findings suggest that in intensely farmed croplands a strategic expansion of current SWF to 11.6% could yield the maximum relative gain in ecological connectivity. This implies an average increase of 6.5% from current woody habitat cover in these landscapes. The initial spatial configuration and shape complexity of woody habitat coverage has a substantial influence on the dynamics between habitat expansion and connectivity enhancement. As a result, the connectivity of woody habitats would not benefit equally from the expansion of existing SWF habitats across all agricultural landscapes; some would require the strategic conversion of strips of agricultural land to “woody features” to effectively enhance connectivity.