Using spoor and prey counts to determine temporal and spatial variation in lion (Panthera leo) density

Abstract

In many African countries, large carnivores such as lions (Panthera leo (L., 1758)) are under serious threat through conflict with people, declining prey abundance, and exposure to disease. Spoor and prey count surveys were used to determine temporal and spatial variation in lion density in Khutse Game Reserve (KGR), Botswana, and the adjacent communal grazing area. Estimated lion density in KGR for the period September 2008 – June 2010 was 41% lower than for the period June 2007 – August 2008 (1.02 vs. 1.72 lions/100 km2). Prior to this population crash in mid-2008, estimated lion density in the communal grazing area (1.21 lions/100 km2) was 30% lower than inside KGR. The relative abundance of the three most abundant, preferred prey species of lions occurring in KGR decreased from 2001 to 2008 by 50%–79%. Based on two prey biomass estimates, the lion population in KGR was below the potential carrying capacity of the habitat after the crash in mid-2008. These results suggest that there could be a human-caused population sink around KGR, which might be strong enough to threaten the long-term survival of lions in the area; particularly if this edge effect is intensified by prey depletion and disease outbreaks, which might have caused the sudden decline in the lion population.