The gharial (Gavialis gangeticus Gmelin) is a fish-eating specialist crocodylian, endemic to south Asia, and critically endangered in its few remaining wild localities. A secondary gharial population resides in riverine-reservoir habitat adjacent to the Nepal border, within the Katerniaghat Wildlife Sanctuary (KWS), and nests along a 10 km riverbank of the Girwa River. A natural channel shift in the mainstream Karnali River (upstream in Nepal) has reduced seasonal flow in the Girwa stretch where gharials nest, coincident with a gradual loss of nest sites, which in turn was related to an overall shift to woody vegetation at these sites. To understand how these changes in riparian vegetation on riverbanks were related to gharial nesting, we sampled vegetation at these sites from 2017 to 2019, and derived an Enhanced Vegetation Index (EVI) from LANDSAT 8 satellite data to quantify riverside vegetation from 1988 through 2019. We found that sampled sites transitioned to woody cover, the number of nesting sites declined, and the number of nests were reduced by > 40%. At these sites, after the channel shift, woody vegetation replaced open sites that predominated prior to the channel shift. Our findings indicate that the lack of open riverbanks and the increase in woody vegetation at potential nesting sites threatens the reproductive success of the KWS gharial population. This population persists today in a regulated river ecosystem, and nests in an altered riparian habitat which appears to be increasingly unsuitable for the continued successful recruitment of breeding adults. This second-ranking, critically endangered remnant population may have incurred an "extinction debt" by living in a reservoir that will lead to its eventual extirpation.
This paper examines the economic value of selected ecosystem services of Corbett Tiger Reserve, India. The direct cost was derived from secondary sources, and indirect and opportunity costs through socioeconomic surveys. For recreational value the individual approach to travel cost method was used, and to assess carbon sequestration the replacement cost method was used.
Forests are one of the major sources of livelihood that need to be conserved. In India, there have been continuous efforts to evolve a scientific basis for sustainable management of forests. In recent century, this has primarily been addressed through "forest management plans," also known as "working plans." To make the plans uniform for each of the forest management units, guidelines have been issued by Government of India in the name of "working plan code,"which are revised periodically to match present days' requirement. A working plan largely deals with the present state of the forest, outcomes of past management, and proposal of future management on a scientific basis. With a significant lapse of time, the role of forests has been recognized beyond mere supply of timber (a major resource) to fulfilling the demands of minor resources and ecological services. This has transformed the basis of forest management and the working plans. With reference to India, we discuss the relevance of working plan for sustainable management of forests; highlights of the most recent working plan code (2014); relevance of the code with reference to climate change and biodiversity, future perspectives, and recommendations for better management of the forests.
1. The gharial (Gavialis gangeticus) is a critically endangered, long-snouted crocodilian, endemic to the Indian sub-continent. Today, the species' distribution and numbers have reduced by more than 95% in all the large rivers where it was formerly abundant. Living upstream in a reservoir dammed in 1976, the Katerniaghat gharial population has continued to nest along the Girwa River, subject to seasonal flooding in recent decades. In 2010, a natural flood upstream in Nepal resulted in a permanent reduction in the mainstream river flow. As a consequence of reduced flow, the formerly open sand banks and mid-river islands have converted gradually to riverbanks with woody vegetation. Coincident with the increased vegetation growth, gharial nesting sites and nest numbers declined by more than 40% by 2018.2. In an attempt to reverse the observed decline in nesting, we intervened with vegetation removal (VR) in 2019 and sand addition (SA) in 2020, to augment available nesting opportunities at previous and potential nesting locations.3. The number of nests increased with SA (n = 36 in 2020) but decreased with VR (n = 19 in 2019), relative to the prior year without intervention (n = 25 in 2018). Furthermore, hatching success increased significantly to 93% with SA, compared to 63% in VR. Creating an artificial sand bank required approximately one-third work hours and cost much less than removing vegetation. Substrate temperatures in and around nests approximated the viable incubation range (29-33.5 • C) when vegetation is absent, but were lower in sites covered with woody vegetation and/or dense, high grass.4. Our study indicates that gharial will respond favourably to newly created sand banks that provide open, sandy riverside nesting areas, in contrast to cut-over sites with dense vegetation removed.5. Finally, we note that this strategy of augmenting nesting sites is only an interim attempt to solve the 'nesting site' dilemma for the river-adapted gharial. Landscapelevel solutions related to resumption of seasonal flooding, and particularly naturalThis is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
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