Dhami Bijaya, Maraseni Tek, Thapa Kanchan, K C Nishan, Subedi Sanskar, Gautam Shreejan, Ayer Santosh, Bayne Erin
Department of Biological Sciences University of Alberta Edmonton Alberta Canada.
University of Southern Queensland Toowoomba Queensland Australia.
Ecol Evol. 2023 Nov 7;13(11):e10661. doi: 10.1002/ece3.10661. eCollection 2023 Nov.
Nepal initiated numerous hydropower and irrigation-related infrastructure projects to enhance and promote green energy, water security, and agricultural productivity. However, these projects may pose risks to natural habitats and the well-being of aquatic fauna, leading to significant effects on delicate ecosystems. To understand these potential impacts, it is crucial to gather reliable baseline data on the population status and habitat characteristics of species. This study specifically focuses on Gharials (), a critically endangered species. We recorded data on pre-determined habitat variables at stations spaced 500 m apart along the two major river streams of Bardia National Park, as well as at locations where Gharials were sighted between February and March 2023. We used binary logistic regression with a logit link function to investigate the habitat characteristics related to the occurrence of Gharials. The presence/absence of Gharials at sampling points served as the dependent variable, while 10 other predetermined variables (ecological variables and disturbance variables) served as independent variables. Our study recorded 23 Gharials, comprising 14 adults, six sub-adults, and three juveniles, with a sex ratio of 55.56 males per 100 females. Most individuals (83%) were found basking. Among the 10 habitat predictors, three variables (mid-river depth, river width, and water temperature) were significantly correlated ( < .05) with the probability of Gharial occurrence. The model shows that Gharial detection probability increases with greater mid-river depth and width and lower water temperature. This study establishes a population baseline for Gharials within the river system before the construction of large infrastructure projects, such as dams and irrigation canals. It also recommends continuous monitoring of Gharial populations after water release and/or diversion to evaluate the impact of large infrastructure projects on the population and their associated habitat characteristics. This will help enable more informed and targeted conservation efforts.
尼泊尔启动了许多与水电和灌溉相关的基础设施项目，以加强和推广绿色能源、水安全及农业生产力。然而，这些项目可能会对自然栖息地和水生动物的福祉构成风险，从而对脆弱的生态系统产生重大影响。为了解这些潜在影响，收集有关物种种群状况和栖息地特征的可靠基线数据至关重要。本研究特别关注印度食鱼鳄，这是一种极度濒危物种。我们在巴迪亚国家公园的两条主要河流沿岸每隔500米设置的站点，以及在2023年2月至3月间发现印度食鱼鳄的地点，记录了预先确定的栖息地变量数据。我们使用带有对数链接函数的二元逻辑回归来研究与印度食鱼鳄出现相关的栖息地特征。采样点印度食鱼鳄的存在/不存在作为因变量，而其他10个预先确定的变量（生态变量和干扰变量）作为自变量。我们的研究记录了23只印度食鱼鳄，其中包括14只成年个体、6只亚成年个体和3只幼年个体，雌雄比例为每100只雌性中有55.56只雄性。大多数个体（83%）被发现正在晒太阳。在10个栖息地预测变量中，有三个变量（河中部深度、河流宽度和水温）与印度食鱼鳄出现的概率显著相关（<0.05）。该模型表明，随着河中部深度和宽度的增加以及水温的降低，印度食鱼鳄被发现的概率会增加。本研究在大坝和灌溉渠等大型基础设施项目建设之前，为河流系统内的印度食鱼鳄建立了种群基线。它还建议在放水和/或引水后持续监测印度食鱼鳄种群，以评估大型基础设施项目对种群及其相关栖息地特征的影响。这将有助于开展更明智、更有针对性的保护工作。
