Efficiently targeting resources to deter illegal activities in protected areas

Summary In many countries, areas delineated for conservation purposes can only achieve their objectives if effective law enforcement occurs within them. However, there is no method currently available to allocate law enforcement effort in a way that protects species and habitats in a cost‐effective manner. Law enforcement is expensive and effort is usually concentrated near the locations of patrol stations where rangers are based. This hampers effective conservation, particularly in large protected areas, or regions with limited enforcement capacity. Using the spatial planning tool Marxan, we demonstrate a method for prioritizing law enforcement in a globally important conservation landscape (the Greater Virunga Landscape, GVL, in central Africa) using data on the spatial distribution of illegal activities and conservation features within the landscape. Our analysis of current patrol data shows that law enforcement activity is inadequate with only 22% of the landscape being effectively patrolled and most of this activity occurring within 3 km of a patrol post. We show that the current patrol effort does not deter illegal activities beyond this distance. We discover that when we account for the costs of effective patrolling and set targets for covering key species populations and habitats, we can reduce the costs of meeting all conservation targets in the landscape by 63%, to 2·2–3·0 million USD, relative to the cost of patrolling the entire landscape. This cost is well within the current expenditure of approximately 5·9 million USD for the GVL but would better target effort from both patrol posts and mobile patrol units in the landscape. Synthesis and applications. Our results demonstrate a method that can be used to plan enforcement patrolling, resulting in more cost‐efficient prevention of illegal activities in a way that is targeted at halting declines in species of conservation concern.