Study links carnivore decline in protected areas to human persecution outside boundary

African Leopard (Panthera pardus pardus), in tree in Serengeti, Tanzania. Image credit, D. Gordon E. Robertson.When it comes to protecting at-risk carnivores like the African leopard, conservationists need to pay particular attention to reducing persecution by humans at the edges of preserves. That's the take-home message from a new study in the journal Animal Conservation that looked at leopards in the contiguous Mkhuze and Phinda Game Reserves in South Africa.

Leopards in the area are killed for trophy hunting and by landowners because of perceived or real threats to livestock. Researchers found empirical evidence for an "edge-effect" in which these types of human disturbances, just beyond the boundary of the protected area, leads to increased mortality and population decline for the animals within the preserve.

Guy Balme and fellow researchers with the organization Panthera and the University of KwaZulu-Natal collared leopards with radio tracking devices in two areas of the preserve complex - one in the core of the protected area and the other near the boundary. They found that leopard density decreased from the core to the edge with the lowest density found on unprotected ranch lands outside the preserve. This was despite the fact that important biological conditions for survival - i.e.. prey availability and competition with other leopards - were similar or better at the edge of the preserves compared to the core.

The leopards living near the boundary suffered from much higher mortality - largely at the hands of humans - and spent more time roaming outside the protected area. The researchers using a model were able to demonstrate that the amount of time spent outside the preserve had a negative effect on leopard survival.

Despite this increased risk, however, leopards did not avoid areas outside the boundaries. The researchers speculate that the areas outside the preserve may act as an ecological trap in which decreased competition for resources with other leopards attracts individuals to the area where they unknowingly face increased mortality risk due to human persecution.

Subsequent to the data collection for the study, conservationists in the area implemented efforts with local communities to reduce hunting pressure on the leopards and the results so far have been promising. The researchers conclude that the concept of the edge effect in protected areas and the consequences for conservation of carnivores has applicability to other settings. They write,

"As human populations continue to increase around protected areas, approaches that manage human activities on both sides of administrative borders will be essential if conservation of wide ranging taxa is to succeed"

--Reviewed by Rob Goldstein

Balme, G., Slotow, R., & Hunter, L. (2010). Edge effects and the impact of non-protected areas in carnivore conservation: leopards in the Phinda-Mkhuze Complex, South Africa Animal Conservation DOI: 10.1111/j.1469-1795.2009.00342.x