4. DISCUSSION
The SNP is a globally recognized area by supporting the word’s largest herd of swamp deer population (Poudel, 2007). However, at present, this species is restricted only in SNP and BNP of Nepal, which has always been at the risk of extinction due to the possible disturbances. Realizing this fact, a study was conducted to find out some suitable areas in CNP of Nepal for translocation them to establish another sub-population (Ghimire et al., 2019), but this might take longer period from translocation programs to establishment of viable sub-populations. Similarly, grazing of domestic cattle is one of the severe problems in the park area that increases competitions with the wild herbivores (Bhattarai, 2012). Thus, we studied about the situation of interspecific competition with spotted deer and domestic herbivores in the study area. The main presumption of this work is that habitat is a main element of the ecological niche (Schoener, 1989)(Chase and Leibold, 2003).
The swamp deer were present in the grasslands predominantly. Wegge et al. (2006) also reported more late successional grasses (Narangaand Themeda spp.) and short grasses (mainly Imperata cylindrica ) in the diet of swamp deer. A total of 55% presence of swamp deer was recorded in the grasslands after fire where they get new sprouts of grass as well as the ash, a source of minerals. They adapted to all types of grassland. According to Moe and Wegge (1997), cut-and-burned treatment gave the increase in forage quality as well as the deer density, as the deer preferred the burned plots. Similarly, a study conducted in Uttarakhand, India has also reported grasses and herbs as the major diet of swamp deer (Tewari and Rawat, 2013). In contrast, the spotted deer did not show many differences in the use of different habitat types. Spotted deer eat both grass and browse, with the former providing the bulk of their diet at all seasons (Kushwaha, 2016). It is predominantly a grazer but consumes more fallen leaves, flowers and fruits in winter/dry season (Sankar, 1994; Sankar and Acharya, 2004; Raman, 2013). It co-existed with the domestic species and was prevalent even near human disturbance areas. The density of spotted deer was 79 km-2 in SNP followed by swamp deer 30 km-2 and hog deer 21.6 km-2 (Karki et al., 2015). They were found uniformly distributed in forests and grasslands. Spotted deer avoided the areas with dense canopy cover confirming their preference for the open forests (Pokharel and Storch, 2016). The dietary overlap of deer and cattle was highest in winter and the competitive interactions occurred in the winter (Jenks et al., 1996). During summer, spotted deer segregated from others from short grasslands and predators’ presence, mixed forest and human disturbances (Bhattarai, 2019). It was mostly recorded in the ecotones such as forest and grassland border (Schaller, 1967; Eisenberg, 1981; Bagchi, 2001). Mixed herds of spotted deer and swamp deer are common on Suklaphanta and Bardia National Parks (Kushwaha, 2016).
These both deer showed the habitat partitioning during the dry season. The spotted segregated from the short grassland and created the suitable environment for the swamp deer. Habitat partitioning is one of the most standard ecological mechanisms to lessen niche overlap and circumvent competition among coexisting species (Rosenzweig, 1981; Traba et al., 2015). Similarly, the spotted deer creates suitable environment to swamp deer consuming the fallen leaves flowers although it is a grazer. The distribution of domestic species shows that the potential for interaction between the wild and domestic species exists more in theShorea forest, floodplain grassland and in the short grasslands. But the distribution of the domestic cattle were not fund so significant in riverine forest, tall grassland and grassland after fire. However, the presence of domestic cattle was observed more near the boundary of the park. Based on the information received from park staffs and filed visit, some of the efforts made by park people to minimize the problem of domestic cattle grazing are mesh wire fencing, electric fencing, intensive patrolling, community awareness etc. Moreover, various habitat management operations are done in few areas to reduce the effect of niche and habitat overlap artificial grass cutting with tractors, waterholes and solar water pumps, controlled fire etc. Likewise, grazing of domestic cattle should be controlled and the plant species utilized by wild ungulates should be protected and increased to minimize the existing competitions. However, detail studies regarding diet composition of these competing species in all seasons and other places are suggested to get clear understanding and information prior to implementing the management activities in the study area.