Connecting urban green spaces: the importance of irregular settlements in biodiversity and peri-urban planning

Urban growth in Southeast Asia is rapidly transforming landscapes and placing biodiversity at risk. There is an urgent need to identify and connect urban green spaces before they are lost to development. As one of the first studies on ecological connectivity in Indonesia, we examined Tangerang Selatan, a rapidly urbanising peri-urban area within the Jakarta Metropolitan Area shaped by extensive land privatisation. We modelled the movement of four mammal groups—small arboreal, small terrestrial, medium-sized arboreal, and medium-sized terrestrial mammals—across fragmented urban green spaces using a land-cover dataset derived from a one-year PlanetScope mosaic (2022–2023), local government land-use data (2022), and OpenStreetMap data (2024). Using high-resolution mapping and connectivity modelling, including least-cost path, corridor, graph, and circuit analyses, we identified the most important habitat connections across the urban landscape. Our results show that riparian corridors and vegetated fragments within irregular settlements are critical for maintaining habitat connectivity, particularly in the less urbanised western part of the study area. Roadside vegetation provided important movement pathways for small mammals, while medium-sized mammals benefited more from green spaces and pathways within irregular settlements. These findings demonstrate that small and often overlooked green spaces can make a substantial contribution to mammal movement in cities. Protecting and restoring riparian buffers and green spaces within irregular settlements could substantially enhance ecological connectivity. Integrating connectivity into urban planning by governments and private developers is therefore essential for sustaining biodiversity and ecological resilience in rapidly growing cities.