The land use and cover change influence the distribution and dynamics of terrestrial biodiversity, ecosystem structure and functioning [1
] leading to alternation of ecosystems [4
] and critical habitats for many of the threatened species worldwide including freshwater ecosystems [5
]. Habitat loss and fragmentation are among the major threats to wildlife populations because the loss of habitat reduces the carrying capacity of the ecosystems, and fragmentation disrupts biological processes and exposes wildlife populations, especially the species with narrow range and specialized habitats [7
]. By 2100, the impact of land use change on biodiversity is likely to be more significant than climate change, nitrogen deposition, species introductions and changing atmospheric concentrations of carbon dioxide on a global scale [10
]. This has a strong implication on conservation and management of protected areas at global, regional and national levels, which are the store house and repository of a wide range of biodiversity [12
Turner et al.
] have argued that ‘land change science’ has now emerged as a central component of global environmental and sustainability research. However, the majority of the literature on ‘land change science’ is in land use patterns either by converting the natural land into human use or changing management practices of human-dominated ecosystems [16
]. There are very little documentations on the change in land cover by natural processes and their consequences on biodiversity [20
]. More importantly, it is a paradox that in spite of being highly rich ecosystem, the wetlands are poorly studied [24
] and are being over-used, underrepresented in protected areas, and having the highest portion of species threatened with extinction [7
In the recent years, Remote Sensing data and Geographical Information System (GIS) have been widely used in conservation planning [25
]. Beyond the mapping of land cover and its impact on biodiversity, the capability now exists to monitor many of the physical and biological characteristics of the land and the impacts of habitat fragmentation and the interactions between landscape patterns and ecological processes [28
]. In our present study, an attempt has been made to observe the spatio-temporal changes of land cover and ecosystems on biodiversity in the Kosi Tappu Wildlife Reserve (KTWR), one of the most diverse wetland ecosystems of eastern Nepal. The main objective of the study was to look at the land cover and ecosystem changes due to natural process of river course change and its potential impacts on the biodiversity of the reserve.
Understanding the nexus between ecosystem change and biodiversity is important but complicates by lack of data on the extent to which these ecosystems are currently managed and conserved. The Millennium Ecosystems Assessment [7
] revealed that only 12% of the world’s inland waters are in protected area network. The World Database on Protected Area records the extent of marine and terrestrial biomes in protected areas but the only freshwater category is “lake systems”, with 1.54% coverage [48
]. At best, existing data suggest that freshwaters have been mostly excluded from protected designations [49
Government of Nepal has initiated the documentation of wetland since 1992 [50
] and the preliminary list accounted for more than 5,000 lakes, 1,380 reservoirs, and 5,183 village ponds in the country [51
]. Among these wetlands, the Government has designated nine important wetlands as Ramsar sites covering about 35,000 hectares of its territory. According to IUCN inventory, there are 163 wetlands in Terai [53
]. The KTWR is the first Ramsar site in Nepal [31
]. History of the reserve shows dense riverine forest and tall grasses, which served as a habitat for large carnivores like Tigers (Panthera tigris
) and Spotted Leopards (Panthera pardus
). Between 1958 and 1964, a barrage was constructed on the river under the Indian aided Koshi Project. Eastern and western embankments bounded the river floodplain, thereby restricting the water from flooding agricultural fields during the monsoons. Subsequently, many large carnivores also disappeared from the area due to continuous degradation of the forested habitat as a result of changes in the river course [54
], and the continuous utilization of the area for fuel wood, fodder and livestock grazing by the growing human population in surrounding villages [55
In the recent years, the geospatial tools have became an important breakthrough for tracking such changes in wetland ecosystems [56
]. Our observation on land cover and ecosystems revealed the dynamic nature of the KTWR. It was observed that after the notification of KTWR in 1976, there has been significant reduction on agricultural practices prevailed in the area. However, there are still some patches of agriculture land observed in the western part of the reserve which is encroached as the boundary is not very well maintained and the river course also keeps changing [55
]. The river course change brought some significant changes on critical ecosystems such as forests and marshes/swamps and others. The Koshi River, which was earlier shifting gradually, changed its course dramatically during the monsoon of 2008 swinging from the main channel to the eastern part of the reserve in the settlement area by making a 2 km breach in the Kusaha VDC (see Figure 3
c,d). This sudden shift in the course of Koshi River has had a dramatic change in the physical landscape. Large track of forest and grassland has been totally washed away and many surrounding agricultural land were covered with sand making them unproductive. KTWR has from the beginning faced tremendous anthropogenic pressure and continues to do so. The flood of 2008 further complicated the problem as the Reserve had to cope with all the externalities ranging from temporary settlement, fuel wood and fodder supply, excessive use of local resources and the construction and repair work of the embankment.
Wetland degradation due to human induced disturbances is becoming a common issue in the Himalaya [57
]. In many cases the critical ecosystems such as water bodies, marshy land and forested areas are degrading [57
]. Unlike the ecosystems changes in wetland elsewhere, KTWR faces additional challenges from the dynamics of river course change, which is a big management challenge for the authority of this protected area. Though systematic species level ecological studies and biodiversity status in the KTWR are limited [55
], and the management has been facing numerous challenges, the wildlife of the KTWR have shown improvement [55
]. Even being one of the smallest protected areas in the country, KTWR provides habitat for a number of endangered species. But the decreasing trend in the original habitats for species such as Wild Water Buffalo, Asiatic Elephant (Elephas maximus
), Indian Bison (Bos gaurus
) and Spotted Leopard and isolation from the nearby population from the protected areas pose a serious threat for long term conservation [55
]. The management challenges are numerous compounded by the river dynamics. Human pressure is increasing and the demand for resources from the reserve also increasing. Habitats for the globally significant species are shrinking and in some cases, the rate is increasing. In the recent years, the remaining forested areas are highly infected by various invasive species including Mikania micrantha.
Therefore, managing KTWR as protected area in isolation is becoming difficult.
From present results, it is evident that KTWR is an important wetland habitat as well as important Ramsar site. The challenges are multiple manifested by climate changes and other drivers of change. Poverty still plays an important role in making local people more dependent on the resources of the KTWR. Therefore, there is an urgent need of system thinking and more serious interventions in poverty alleviation. It is also important to have a regular monitoring of species distribution, population and impacts of floods on the habitats and species. Though the park management regularly conduct species census, they are mostly targeted for higher species such as Wild Water Buffalo. More intensive and regular monitoring for other species including extension of invasive species and their impacts on native species are desirable. Moreover, integrated approach and alternative livelihood options for the people who are dependent of the KTWR have to be designed and implemented.
ICIMOD in partnership with Wetlands International, WWF, IUCN and other local NGOs are supporting the governments in the region to establish the ‘Himalayan Wetlands Initiative’ within the framework of regional cooperation under the Ramsar Convention since 2002 [67
]. The initiative addresses the wetland issues from global to regional and local levels in achieving the goals of conservation and wise use of wetlands as a contribution to sustainable development. Its mission is “to sustain and restore wetlands, their resources, and biodiversity for future generations”. The initiative is aimed to establish a regional forum for integrated wetland conservation through wise use of resources, and at the same time providing a basis for regional cooperation. This cooperation has led to the development of a regional strategy for conservation of wetlands and is the driving force behind development of the capacity-building framework, tools for wetlands, and the wetland information system. However, new challenges posed by climate change needs to be integrated in overall biodiversity conservation and management agendas in the wetland. Since 2012, ICIMOD in collaboration with its member countries of the HKH and Ramsar Secretariat would like to propose a program for better understanding the role of Ramsar sites on their biodiversity values, the potential impact of climate change and their consequences on the local development agendas. Especial emphasis will be given to the peat lands to understand their role on carbon sequestration and the consequence of climate change on the state of such peat lands.