Evaluating wire-snare poaching trends and the impacts of by-catch on elephants and large carnivores

Wire snare poaching is widespread in Africa yet snaring trends, patterns and the impacts of by-catch on non-target threatened species such as elephant (Loxodonta africana), lion (Panthera leo) and African wild dog (Lycaon pictus) are poorly understood. We conducted retrospective analyses of data from 1038 anti-poaching patrols conducted in Zambia’s Luangwa valley from December 2005 to November 2010, to evaluate snaring dynamics and the effect of season, patrol size and length on snare detection. We also assessed impacts of by-catch on elephant, lion, and wild dog populations critical to the area’s wildlife tourism-based economy. Snaring mortality increased overall elephant poaching offtake by 32%. Approximately 11.5% of the adult and subadult lion population and 20% of the adult (>4 years) males were snared. Snared dogs occurred in 67% of packs (n = 6), comprising 14–50% of adult and yearling pack members (median = 20%) and 6–16% of a resident population (median = 6%) already at minimum viable pack size (mean = 5.6). Evidence for seasonal and annual trends differed by patrol type, yet substantial evidence of positive interannual and seasonal trends in snaring existed and there was no evidence of a decreasing trend. Because patrols are intended to reduce poaching and enforcement is adaptive toward increasing snare detection, evaluations of snaring trends from patrol data are potentially confounded; thus we recommend that a portion of the overall patrol effort for anti-poaching should be devoted to non-adaptive surveys under fixed, well-designed protocols to enable unbiased tracking of snaring trends over time and objective evaluation of anti-poaching and community conservation efforts. In addition precautionary management emphasizing increased law enforcement is essential to protect existing wildlife-based economies and resources.