Department of Anthropology, Durham University, Dawson Building, South Road, Durham, DH1 3LE, UK.
Primate and Predator Project, PO Box 522, Louis Trichardt, 0920, South Africa.
Sci Rep. 2021 Jan 12;11(1):620. doi: 10.1038/s41598-020-77188-7.
Wildlife population density estimates provide information on the number of individuals in an area and influence conservation management decisions. Thus, accuracy is vital. A dominant feature in many landscapes globally is fencing, yet the implications of fence permeability on density estimation using spatial capture-recapture modelling are seldom considered. We used camera trap data from 15 fenced reserves across South Africa to examine the density of brown hyaenas (Parahyaena brunnea). We estimated density and modelled its relationship with a suite of covariates when fenced reserve boundaries were assumed to be permeable or impermeable to hyaena movements. The best performing models were those that included only the influence of study site on both hyaena density and detection probability, regardless of assumptions of fence permeability. When fences were considered impermeable, densities ranged from 2.55 to 15.06 animals per 100 km, but when fences were considered permeable, density estimates were on average 9.52 times lower (from 0.17 to 1.59 animals per 100 km). Fence permeability should therefore be an essential consideration when estimating density, especially since density results can considerably influence wildlife management decisions. In the absence of strong evidence to the contrary, future studies in fenced areas should assume some degree of permeability in order to avoid overestimating population density.
野生动物种群密度估计提供了一个区域内个体数量的信息，并影响保护管理决策。因此，准确性至关重要。在许多全球景观中，围栏是一个主要特征，但围栏渗透率对空间捕获-再捕获模型进行密度估计的影响很少被考虑。我们使用来自南非 15 个围栏保护区的相机陷阱数据，研究了棕色鬣狗（Parahyaena brunnea）的密度。我们估计了密度，并在假设围栏保护区边界对鬣狗运动具有渗透性或不可渗透性的情况下，对其与一系列协变量的关系进行了建模。表现最佳的模型是那些仅包含研究地点对鬣狗密度和检测概率影响的模型，而不考虑围栏渗透率的假设。当围栏被认为是不可渗透的时，密度范围从每 100 公里 2.55 到 15.06 只，但当围栏被认为是可渗透的时，密度估计平均低 9.52 倍（从每 100 公里 0.17 到 1.59 只）。因此，在估计密度时，围栏渗透率应该是一个重要的考虑因素，尤其是因为密度结果会极大地影响野生动物管理决策。在没有相反的有力证据的情况下，未来在围栏区域的研究应该假设一定程度的渗透性，以避免高估种群密度。
