Creating and preserving protected areas (PAs) is a primary strategy of global biodiversity conservation efforts, such as the 30×30 target. When protected areas form a connected network that allows species to move and populations to interact, they’re more effective at sustaining biodiversity over the long term. However, past efforts have shown that reaching large-scale conservation targets using PAs alone is difficult, especially when suitable land is limited or already inhabited.
To meet the 30×30 goal, conservation planners are beginning to consider other effective area-based conservation measures (OECMs). These represent places that provide benefits for biodiversity and potentially support landscape connectivity, even though conservation is not their main purpose. OECMs can include Indigenous-managed lands, community forests, or even military training grounds.
Brodie, J.F., Deith, M.C., Burns, P., Goetz, S., Cunningham, C., Hill, J.K., Reynolds, G. and Mohd-Azlan, J. 2025. The contribution of other effective area-based conservation measures (OECMs) to protecting global biodiversity. Nature Communications 16(1):7886.
They were first recognized in the 2010 Aichi Biodiversity Targets, but their definition remains vague, and policies for recognizing and managing them vary widely among countries. Because OECMs are relatively new, it’s still unclear how well they can help conserve biodiversity or link protected areas into functional networks.
Recent research has begun to fill this gap by quantifying how OECMs contribute to conservation in terrestrial (Colombia and South Africa) and marine (the Philippines) ecosystems. The study focused on two key questions: 1) are OECMs being placed in areas that are important for biodiversity and ecosystem services, such as Key Biodiversity Areas or critical connectivity locations?; and 2) in terrestrial systems, does designating an area as an OECM lead to lower rates of deforestation over time? The analysis compared metrics between OECMs and unprotected locations, and assessed landscape connectivity using circuit theory.
The results reveal that OECMs had uneven success across the three regions. South African OECMs were more often found in high-priority conservation areas, while Colombian OECMs were typically in lower-priority areas and Philippine OECMs were statistically similar to unprotected sites.
Across all three countries, OECMs did a poor job of covering areas that support landscape or seascape connectivity. South Africa’s OECMs had slightly higher connectivity than unprotected areas, but not at a level likely to help wildlife move between protected areas. In Colombia, forest loss within OECMs declined by nearly 80% after designation, showing a tangible conservation benefit, while deforestation rates showed little change in South Africa.
These findings suggest that the effectiveness of OECMs depends heavily on how each country chooses to implement and support them. Many have been designated opportunistically by local entities rather than through national strategies, leaving gaps in coverage and connectivity. Developing coordinated regional or national plans that deliberately incorporate OECMs into conservation networks could make them far more effective. If future OECMs are placed in areas of high conservation value and positioned to link existing protected areas, they could play a meaningful role in achieving the 30×30 goal and enhancing global biodiversity connectivity.
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