Gharial (Gavialis gangeticus) is one of the most highly threatened fauna of fresh water ecosystems in the world. Yet, information about the species habitat characteristics influencing its distribution and threats to its existence are still lacking in Nepal. This study identified the most important habitat characteristics associated with gharial presence and existing threats in the Rapti River of Nepal. An opportunistic search method was adopted for field surveys conducted in November and December of 2018. As part of the survey, Global Positioning System (GPS) coordinates were recorded for each sighting location and gharial behavioral activity was captured from photographic documentation. Habitat characteristics were recorded at stations spaced at 500 m intervals along the river in addition to locations where gharial was sighted. Data were collected moving downstream on each side of the river (left and right banks), which included both stations and sighting locations that comprised a total of 200 sampling points. Habitat factors associated with the presence of gharial were analyzed using a combination of MS Excel, ArcGIS and the R Binomial distribution model with logit link function. The dependent variable was the presence or absence of gharial at sampling points and the independent variables included six unique habitat characteristics: riverbank location, river width, mid-river depth, riverbank substrate type, riverbank slope and observed anthropogenic threats. Relative whole-site ranking was used to identify the most prominent threats to conservation. During the survey, 53 gharial individuals were recorded where 62% were found basking while 38% were found swimming or submerged underwater. A majority of individuals were sighted on the south side (left bank) of the Rapti River (31 out of 53 sightings), at river widths of 51–100 m (34 out of 53 sightings) and at mid-river depths of 1–2 m (28 out of 53 sightings). Other important factors were riverbank substrate type where most of the gharials were found basking in the sandy bank (25 out of 53 individuals), flat riverbank topography (42 out of 53 individuals), and at locations with no observed anthropogenic threats (41 out of 53 individuals). Among the six habitat variables examined, no significant differences in the probability of gharial sightings were found for five variables (river side, observed human threats, substrate type, river width and mid river depth) while only one habitat variable, topography, exhibited significant differences in the probability of gharial sightings (χ2 _4,195 = 38.782; p < 0.001). Pollution by industrial toxic wastes, domestic sewage and natural habitat modification due to monsoon flash floods were the major threats to gharial and their habitat. Although the Rapti River currently supports a significant gharial population, conservation efforts need to be increased in the future from authorities responsible for their stewardship in order to maintain and enhance their numbers through both habitat protection and abundance of prey (fish).

加里尔（Gavialis gangeticus）是全球淡水生态系统中受威胁最大的动物之一。但是，尼泊尔仍然缺乏有关影响其分布和对其生存构成威胁的物种栖息地特征的信息。这项研究确定了尼泊尔Rapti河中与食盐存在和现有威胁相关的最重要的栖息地特征。2018年11月和12月进行的野外调查采用了机会搜索方法。作为调查的一部分，对每个瞄准点记录了全球定位系统（GPS）坐标，并从摄影文档中捕获了gharial行为活动。在沿河沿线间隔500 m的站点上，除了观察到gharial的位置以外，还记录了栖息地特征。在河的两边（左，右岸）向下游移动，收集了数据，包括站和瞄准点，总共包括200个采样点。使用MS Excel，ArcGIS和具有logit链接功能的R二项式分布模型对与食盐动物存在相关的栖息地因素进行了分析。因变量是采样点上是否有盖尔河，自变量包括六个独特的生境特征：河岸位置，河宽，河中深度，河岸底物类型，河岸坡度和观测到的人为威胁。整个站点的相对排名用于确定对保护的最主要威胁。在调查期间 记录到53个食人个体，其中62％被发现有晒太阳，而38％被发现游泳或被淹没在水下。在拉普蒂河（53处目中的31处）的南侧（左岸），51–100 m的河宽（53处目中的34处）和河中深度1–1处发现了大多数人。 2 m（53个目击者中的28个）。其他重要因素是河床底物类型，其中大部分杂物在沙质河岸（53个人中占25），平坦的河岸地形（53个人中42）和在没有观测到人为威胁的位置被发现。 53个人）。在所检查的六个栖息地变量中，发现五个变量（河岸，观察到的人类威胁，底物类型，2 _4,195  = 38.782; p <0.001 ）。工业有毒废物造成的污染，生活污水和季风骤发洪水造成的自然栖息地改造，是对加里尔河及其栖息地的主要威胁。尽管Rapti河目前支持着大量的鱼类种群，但未来需要由负责其管理的当局加大保护力度，以通过栖息地保护和丰富的猎物（鱼类）维持并增加其数量。