The respective role of climate mitigation, sustainable land use and area-based conservation to curb future biodiversity loss

Increasing conservation efforts are required to avert biodiversity decline caused by climate and land use changes. In a recent study (Hari et al. 2024; preprint), we combined climate change scenarios (RCP2.6 and RCP6.0) and land use change projections to assess their impact on future species distribution for a large number of mammals, birds and amphibians. Future projections of land use change were derived from the Land Use Harmonization dataset v2 (LUH2), which does not make any explicit assumptions about the area under protection in these scenarios.

Here, we extend the scope of our future biodiversity projections by adding an additional layer of different protected area (PA) scenarios. In the first conservation scenario, we fix the PAs based on the World Database on Protected Areas (WDPA), thereby assuming that PAs will remain the same in the future as it is today. In a second category of scenarios, we create land use scenarios compatible with the Global Biodiversity Framework’s “30 by 30” target based on the spatially optimized dataset by Jung et al. (2021) combined with LUH2.

We show that combining climate mitigation measures with sustainable land use is more beneficial for biodiversity than any PA scenario alone. However, PA expansion significantly reduces species loss, particularly in biodiversity hotspots. While any level of area-based conservation yields notable biodiversity benefits, the 30% PA target proves especially effective under high-emission scenarios, preventing up to 11.2% more land use-driven species loss in regions such as West, Central, East and South Africa compared to scenarios without PAs.