Abstract:
The cheetah Acinonyx jubatus has suffered dramatic range contractions and population
declines as a result of habitat degradation, prey depletion and conflict with
humans. Of further concern is that many of Africa’s remaining cheetah populations
persist in human-dominated and highly fragmented landscapes, where their
ecology is poorly understood and population data are lacking. Presence–absence
surveys may be a practical means to collect these data; however, failing to account
for detection error can lead to biased estimates and misleading inferences; potentially
having deleterious consequences for species conservation. The goal of this
study was to identify how an occupancy modelling technique that explicitly
accounts for detectability could be used for quantifying cheetah status in humanimpacted
landscapes. Replicated camera-trap and track surveys of 100-km2 sample
units were used to estimate the proportion of area occupied by cheetahs and to
determine the survey effort required to inform conservation planning. Based on our
results, 16 km [±standard error (SE) = 12–22] of walking or 193 camera-trap nights
(±SE = 141–292) are required to confirm cheetah absence at a given 100-km2 grid
cell (with 95% certainty). Accounting for detection resulted in an overall cheetah
occurrence estimate of 0.40 (SE = 0.13), which is 16% higher than the traditional
presence–absence estimate that ignores detection error. We test a priori hypotheses
to investigate factors limiting cheetahs using an occurrence probability model of
their preferred prey. The results show that both cheetahs and their prey were
strongly negatively influenced by human settlements. Our study provides an unbiased
estimate of occurrence that can be used to compare status across different sites
and as a basis for long-term monitoring. Based on our results, we suggest that track
and/or camera-trap surveys coupled with site occupancy models may be useful for
targeted monitoring of cheetahs across their distribution.
