Urban development, land sharing and land sparing: the importance of considering restoration

1. At present, there is limited knowledge of how best to reconcile urban development with biodiversity conservation, and in particular whether populations of wild species would be greater under low-density housing (with larger gardens), or high-density housing (allowing more area to be left as undeveloped green spaces). The land sharing/sparing framework – originally developed in the context of farming – can be applied to address this question.
2. We sampled the abundance of trees in the city of Cambridge, UK, along a gradient of human density. We designed different scenarios of urban growth to accommodate the human population predicted in 2031. For each scenario, we projected the future city-wide tree population size and quantified its carbon sequestration potential. We also considered, for the first time in an urban sharing-sparing context, the implications of habitat restoration on degraded urban green space.
3. We found that the density of most native and non-native tree species i...