Ezat Mohamed A, Molenaar Elke, Naguib Marc, van Langevelde Frank
Behavioural Ecology Group Wageningen University & Research Wageningen the Netherlands.
Wildlife Ecology and Conservation Group Wageningen University & Research Wageningen the Netherlands.
Ecol Evol. 2025 Sep 2;15(9):e71970. doi: 10.1002/ece3.71970. eCollection 2025 Sep.
Conflict between wildlife and humans is one of the main causes of wildlife decline. Numerous studies have investigated environmental and anthropogenic variables determining the distribution of large carnivores to predict and mitigate the risks of such conflicts. However, for aquatic carnivores, such as crocodiles, little is known about which variables explain their distribution. Yet, human-crocodile conflicts are on the rise. A better understanding of such variables will potentially prevent conflicts or even promote coexistence between crocodiles and humans. Here, we analyze which environmental and anthropogenic variables determine the distribution of Nile crocodiles () in Lake Nasser, Egypt. As apex predators, Nile crocodiles are often perceived to be responsible for the declining fish populations, and proximity to fishermen could lead to conflicts and killing of crocodiles. Since both crocodiles and fishermen hunt fish, we expected to find Nile crocodiles close to fishermen's camps. To analyze the crocodile distribution, we surveyed 1880 km of Lake Nasser's shoreline and collected 192 sightings of Nile crocodiles. We used readily available spatial data for 23 environmental and anthropogenic variables, including ambient temperature, the slope of the shoreline, and the distance to fishermen's camps. We used MaxEnt species distribution modeling to quantify which variables were correlated with Nile crocodile locations. Our analyses revealed a higher probability to find Nile crocodiles closer to fishermen's camps. Additionally, crocodile presence was positively associated with flat shorelines. The findings that crocodiles are not driven away by fishing activities reflect a conflict between fishermen and crocodiles. This study contributes to an understanding of which environmental and anthropogenic variables determine the distribution of Nile crocodiles, a key conservation point to promote human-crocodile coexistence.
野生动物与人类之间的冲突是野生动物数量减少的主要原因之一。众多研究调查了决定大型食肉动物分布的环境和人为变量,以预测和减轻此类冲突的风险。然而,对于水生食肉动物,如鳄鱼,关于哪些变量能解释它们的分布情况,我们所知甚少。然而,人类与鳄鱼的冲突却在不断增加。更好地了解这些变量可能会预防冲突,甚至促进鳄鱼与人类的共存。在此,我们分析哪些环境和人为变量决定了埃及纳赛尔湖尼罗鳄()的分布。作为顶级食肉动物,尼罗鳄常被认为应对鱼类数量的减少负责,靠近渔民可能会引发冲突并导致鳄鱼被猎杀。由于鳄鱼和渔民都以鱼为食,我们预计会在靠近渔民营地的地方发现尼罗鳄。为了分析鳄鱼的分布情况,我们对纳赛尔湖1880公里的湖岸线进行了调查,并收集到192次尼罗鳄目击记录。我们使用了23个环境和人为变量的现成空间数据,包括环境温度、湖岸线坡度以及到渔民营地的距离。我们使用最大熵物种分布模型来量化哪些变量与尼罗鳄的位置相关。我们的分析表明,在靠近渔民营地的地方发现尼罗鳄的可能性更高。此外,鳄鱼的出现与平坦的湖岸线呈正相关。鳄鱼并未因捕鱼活动而被驱离这一发现反映了渔民与鳄鱼之间的冲突。这项研究有助于理解哪些环境和人为变量决定了尼罗鳄的分布,这是促进人类与鳄鱼共存的关键保护要点。