| dc.description.abstracteng | Poaching is a global environmental threat, which drives populations of many species toward extinction. Current levels of poaching are unsustainable, causing substantial impacts on ecosystems and wildlife. By poaching, humans also limit the prey resources of large carnivores. Therefore, human hunters may compete with large carnivores over food resources and threaten their survival. However, the threat to large carnivores from prey depletion has rarely been quantified. In this study, I assessed the trophic competition between the endangered Persian leopard (Panthera pardus saxicolor) and local poachers in Golestan National Park, Iran.
Using data from 36 feeding trials in zoos, I developed novel leopard-specific correction factors (chapter 2) for robust estimation of biomass (CF1) and number of consumed prey from scat data (CF2). I used a new approach in calculation of CF2, limiting the maximum consumption rate to 25 kg for heavier prey species, which is in accordance with feeding ecology of leopards in the wild. I estimated leopard diet using 77 scat samples from across the park and compared the prey hair remains with available reference collections (chapter 6). Leopard diet consisted of 12 different species, the majority (81% biomass consumed) of which were from wild ungulate species. Wild boar (Sus scrofa) comprised most of the leopard diet (50.2% biomass consumed) and other important species were bezoar goat (Capra aegagrus) and urial (Ovis vignei). Also, the considerable amount of livestock (sheep, goat and cattle) and dog (17.1% biomass consumed) included shows existence of an alarming human-leopard conflict in the study area.
I estimated the abundance of four main species hunted by leopard and poachers by line transect sampling (186 km), camera trapping (2777 camera days), double-observer point-counts (64 scans) and dung counts (38 km) (chapters 3, 4 and 5). The populations of bezoar goat, red deer (Cervus elaphus) and urial showed a 66-89% decline in the past decades due to poaching. However, in the absence of poaching pressure due to religious prohibition of pork consumption, the population of wild boar showed an 58% increase compared to the 1970’s estimates. The local poachers’ incentives for ungulate poaching (in non-ordinal manner) included poverty/subsistence, hunting for meat market/trade, pleasure/love of hunting, tradition/habits, and hunting for revenge/conflict with conservation regulations and bodies (chapter 5). Furthermore, the results of multivariate analyses of urial and leopard distribution (chapter 3) suggested that poaching pressure causes higher concentration of urials around ranger stations where they benefit from higher law enforcement levels.
I compared leopard prey preference with prey offtake by poachers (75 poacher seizure records). Persian leopards highly preferred bezoar goat despite its lower abundance. Wild boar and red deer were predated according to their abundance, and urial was avoided by leopards. Moreover, using a novel livestock spatiotemporal availability coefficient, I determined that leopards show high avoidance of small livestock. Local poachers preferred red deer, urial and bezoar goat and strongly avoided wild boar hunting. Interview data from local poachers revealed that the highest stated preference was for hunting urial, followed by red deer and bezoar goat. Both leopard (niche breadth 0.24) and poachers (niche breadth 0.19) showed hunting specialization. Also, both apex predators showed exclusivity (niche overlap 0.31) in their dietary/hunting niches, which suggests the lack of exploitative competition.
This pattern likely results from the major role of wild boar in leopard diet and its avoidance by poachers. Considering the general avoidance of Suidae species across the leopard range, depletion of alternative prey species may have resulted in a prey-switching strategy by leopards. In spite of low dietary competition with poachers, limited prey choice may threaten the long-term survival of leopards. In conclusion, conservation should focus on reversing rapidly declining ungulate populations by improving control of current poaching pressure, which affects large carnivores as well. More efficient law enforcement practices and initiatives targeting a combination of economic and non-economic incentives are recommended to avert local people from poaching. | de |