Contribution of private gardens to habitat availability, connectivity and conservation of the common pipistrelle in Paris

Urban sprawl is one of the greatest global changes with major negative impacts on biodiversity and human well-being. Recent policies have acknowledged the value of urban green areas in counterbalancing such impacts. These policies aim to increase the ecological value of green areas, making cities more permeable to natural populations. However, they are largely focused on the role and management of public green areas, ignoring the role and potential of private green areas for urban ecological value. This study aims to evaluate the benefits of considering private green areas for conservation efforts in cities. Using data on bat activity and information on vegetation and building height, we quantify the respective role of public and private green areas in habitat availability and connectivity for the common pipistrelle in the city of Paris, France. Our results show that despite the low proportion of private green areas in Paris (36% of the total green areas), they still contributed up to 47.9% of bat habitat availability and decrease the resistance of the city matrix by 88%. The distribution in the city matrix and vegetation composition of those areas appeared especially beneficial for bat habitat availability and connectivity. The study demonstrates the importance of private green areas in the ecological value of cities in complementing the role of public green areas. Our results confirm the need to develop more inclusive urban conservation strategies that include both public and private stakeholders.