The Dian Fossey Gorilla Fund International, Musanze, Rwanda,
The Dian Fossey Gorilla Fund International, Musanze, Rwanda.
Folia Primatol (Basel). 2021;92(2):112-125. doi: 10.1159/000514626. Epub 2021 Mar 23.
To accurately determine the space use of animals, we need to follow animal movements over prolonged periods, which is especially challenging for the critically endangered Grauer's gorillas (Gorilla beringei graueri) in eastern Democratic Republic of the Congo (DRC). As a consequence, we know little about Grauer's gorillas, particularly from the lower elevational parts of their range. Between 2016 and 2018, we tracked unhabituated Grauer's gorillas in lowland forests (500-1,000 m a.s.l.), at the community-managed Nkuba Conservation Area in Nord Kivu (DRC) to provide estimates of daily travel distances (DTD), daily displacement distances (DDD), and the linearity of recorded paths expressed as the Linearity Index (LI): DDD/DTD. We found an average DTD of ∼1.3 km (range 0.05-5.0 km), with temporal variation among monthly averages; specifically, an increase in travel distance over the June-August dry season resulting in peak travel distances at the beginning of the September-December wet season. Daily displacements showed similar temporal variation, which resulted in a lack of obvious temporal patterns in LI. We conclude that the movement patterns of Grauer's gorillas in lowland forests, which are characterized by larger DTD than those of Grauer's gorillas that inhabit highland habitats, show similarity to travel distances of other predominantly frugivorous gorillas. Moreover, the observed temporal patterns in space use may be tentatively linked to temporal changes in fruit availability or consumption. These observations have consequences for our understanding of the ecological role that Grauer's gorillas play and provide baseline data to estimate current and future distributions, abundances, and carrying capacities of this highly threatened animal.
为了准确确定动物的空间利用情况，我们需要长时间跟踪动物的活动，这对于刚果民主共和国（DRC）东部极度濒危的格雷氏大猩猩（Gorilla beringei graueri）来说尤其具有挑战性。因此，我们对格雷氏大猩猩知之甚少，特别是在它们的低海拔地区。在 2016 年至 2018 年期间，我们在北基伍社区管理的恩库巴自然保护区（位于低地森林，海拔 500-1000 米）中追踪了未被惯常跟踪的格雷氏大猩猩，以提供每日旅行距离（DTD）、每日位移距离（DDD）和记录路径线性度的估计值，用线性指数（LI）表示：DDD/DTD。我们发现平均 DTD 约为 1.3 公里（范围为 0.05-5.0 公里），每月平均值存在时间变化；具体来说，6 月至 8 月旱季的旅行距离增加导致 9 月至 12 月湿季开始时的旅行距离达到峰值。每日位移也表现出类似的时间变化，导致 LI 没有明显的时间模式。我们得出的结论是，低地森林中格雷氏大猩猩的运动模式以较大的 DTD 为特征，与栖息在高地栖息地的格雷氏大猩猩的运动模式相似，与其他主要以水果为食的大猩猩的旅行距离相似。此外，观察到的空间利用时间模式可能与果实可用性或消耗的时间变化有关。这些观察结果对我们理解格雷氏大猩猩所扮演的生态角色具有重要意义，并为估计这种高度受威胁动物的当前和未来分布、数量和承载能力提供了基线数据。
