Study on status, distribution and threats to Gharial in Rapti River of Chitwan National Park, Nepal. .PDF.
Abstract
The gharial is considered to be one of the most critically threatened of all crocodilians, becoming alarmingly close to extinction in the 1970s. Because of the evidence of widespread and rapid population decline, gharial was listed by IUCN, the World Conservation Union, as ‘Critically Endangered’, which is the highest category of endangerment. In response to rapid population decline Nepal listed gharial in its protected species and started the restocking program from 1978 with the establishment of captive breeding center at Chitwan National Park. The Department of National Park and Wildlife Conservation through its captive breeding program, is regularly releasing the gharials in the rivers but the population has not stabilized and is at the edge of extinction. The study has been conducted to determine status of gharial with factors affecting to estabilize the population in the Rapti river of Chitwan National Park. The study was divided in to two seasons breeding and non breeding season. Data on population, nests and nesting sites, and threats to animal were collected. A social survey among local people was also conducted to understand their perception on gharial conservation. The population size of gharial was estimated as 26. Gharial sightings were found to be more in breeding season.
The population of male was very few and the sex ratio was found to be 1:9 in the study area which is critical factors to be consider in conservation of declining gharial. Total 3 nests were found in the Rapti River with average clutch size 33 and all nests were along Sauraha-Kasara section. Out of total, 50% of eggs were success to hatch and produced hatchlings while other 50 % were found to be damaged in case of wild nests whereas about 49% of eggs were success to hatch in case of nests at captivity. The major threats to gharial in Rapti River were fishing, disturbance by people, sand mining, use of gill net and cleaning and washing activities. It was found that less the weighted mean of threats more the number of gharial suggesting immediate need to control threats level. Majority of respondents showed the positive attitude for collaborative conservation activities between the park and local people. A breeding and restocking program by the Park is in effect for several years; however the study shows that there is high risk of ecological disaster of gharial. From the study it is found that there is habitat degradation with human disturbance, lack of proper care of nests and no regular measurement of nest temperature and humidity.