Theses and Dissertations
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Item Abundance and social organization of male Asian elephants (Elephas maximus) in Rajaji Tiger Reserve(Wildlife Institute of India, Dehradun, 2024) Madhusudanan, Abhimanyu; Pandav, Bivash; Lakshminarayan, N.; Mondol, Samrat1. Asian Elephants are complex, social, and polygynous mammals living in fission-fusion societies. Male elephants are known to alternate between leading solitary lives, in all-male groups or associating with mixed-sex herds. All-male groups allow younger males to learn from older males, test strengths and spar with their peers. While much work has been done on female Asian elephant societies, studies focused on male association patterns are limited, but gaining importance in the light of human-elephant conflicts. In this study, I estimated the abundance of adult male elephants in a stretch of forest spanning over 40 km along the east bank of the river Ganga in Uttarakhand using a polygon search-based spatially explicit capture recapture (SECR) framework 2. I invested a survey effort of ~3014 km to estimate the abundance of the adult male segment of the population using a capture-recapture framework. Using a combination of morphological features, I identified 34 adult males from 124 elephant sightings. Association patterns of the male elephants, following behavioural sampling approaches were also recorded during the surveys. 3. Adult male elephant density was 0.05 (SE=0.01)/km2, and a derived abundance of 40 (SE=1.4) for the 475 km2 study area. This demonstrates that polygon search-based SECR is an effective approach in estimating elephant abundance.Item Dry season forage selection by Asian elephant (Elephas maximus) in a fragmented landscape, northern West Bengal(SACON, 2020) Das, Priyanka; Kumara, H N; Kshettry, AritraThe Asian elephant is a wide-ranging species with just 51% of its range across Asia covered by forest land. Hence, it is imperative to plan conservation action in the other half comprising of multiuse landscapes. With food being an important resource determining elephant use and movement, understanding their forage selection in a heterogeneous landscape can help us prioritise allocation of limited conservation resources. I studied forage selection by Asian elephants during December 2019 to June 2020 in a tea-estate-agriculture-forest mosaic in northern West Bengal, a landscape which typifies land-use mosaics used by elephants across India. Asian elephants in the landscape consumed 132 plant species, of which 21 species constituted 85.3% of the total feeding signs recorded, while non-reproductive plant parts dominated the diet. The mean (±SE) feeding frequency was found to be highest in villages [50.15 (±22.85)] followed by forests [40.51 (±9.42)], semi-open forests [12.14 (±9.42)], tea estates [5.79 (±1.95)] and open forests [3.31(±1.44)]. However, the high variance in village indicates that elephants use villages for movement and forages occasionally. Food grain from household was consumed rarely (0.25%). Overall, they used dicots (52.73%) more than monocots (47.27%) and browse (65.23%) more than herb (34.77%). Elephants consumed more monocots in forests and tea estates whereas in semi-open forests, open forests and villages they consumed more dicots. The availability of monocots was lesser than dicots in all these land use and land cover types. In forest, they consumed more herbs, whereas browse was consumed more in all other land use and land cover types.Item Nutritional Ecology of Asian Elephants (Elephas maximus) in Chilla Range of Rajaji National Park, Uttarakhand(Wildlife Institute of India, Dehradun, 2009) Datta, Suniti Bhushan; Goyal, S.P.; Sathyakumar, S.Responses of animals to the habitat has been the central focus for management of species and of these aspects, nutritional ecology has been the key issue in foraging behaviour studies and habitat studies. Therefore, the study focused on the nutritional aspect of forage selection by Asian elephants (Elephas maximus) in Chilla Range of Rajaji National Park. The main objectives were to determine whether habitat structural heterogeneity or nutritional quality of the selected food plant species was a determinant in the temporal and spatial habitat use by elephants and to determine the reasons behind seasonality in foraging. The study area of 148km2 in Chilla Range of Rajaji National Park was divided into twelve 2x2km grids, and these were further divided into 4 sub-grids each. In each sub-grid, a 1 km long line transect was laid and along this 10m radial plots were placed at 100m intervals. Vegetation data were collected to characterize the habitat structural heterogeneity in terms of number of trees of each species, height of canopy base, canopy volume, percent canopy cover, species diversity, species density and geo-spatial variables such as NDVI, standard deviation of slope, mean elevation and the proximity to water. Parts of 12 most-preferred plant species were collected in the study areas for estimating nitrogen, ash, acid detergent fibre, and macro and micro minerals such as sodium, potassium, calcium, copper, magnesium and zinc. During the study period from December 2008 to May 2009, Elephant response was determined in terms of dung density along the 1km transect in winter and in summer. The total number of trees in each grid varied from 124 to 268. Tree diversity ravged betweel) 0.456-1.454. Height of canopy base was mostly 1.5-3.0 m, although two grids showed extremely high canopy bases. Canopy volume ranged from 165.63m3 to 948.36m3 , although the majority of the grids showed a high variation in canopy volume in terms of standard deviation (SE). The percent canopy cover ranged from 54.13% to 93.72%. Most of the NDVI values were _high in the study area (>0.180), while one grid showed a low value of 0.143. For the standard deviation of slope, the values ranged from a low of 2.46 to a high of 8.46. The mean elevation of the study area ranged froin 391-840m a.s.l. Nutritional values estimated for most of the parameters in winter and summer from selected plant samples collected in the study area showed slight variations 4 between seasons. Percent nitrogen content indicated no seasonal difference (f=0.98, p=0.05, df=ll). The percent acid detergent fibre indicated a difference (P<0.05,df=I I) between the two seasons. Percent ash content was found not significantly different (p=O.l6, p=0.05, df=l1) between seasons. Amongst the macro and micro minerals, sodium content was significantly different across the two seasons. Potassium content was found to be significantly different across the seasons (p<0.05). Calcium content was also found to be significantly different between winter and summer (P<0.05). The copper content could not be compared across the seasons as in summer the levels present in plant samples were too low to be detected by the instrument. The difference in magnesium and zinc content across the two seasons were not significant (p=0.16 and P=0.31). Dung density in the grids across both seasons was non-uniform and highly skewed (p<0.05, df=47). The dung densities in both seasons were related more with the habitat heterogeneity variables than nutritional values obtained in each grid. The relationship between dung density and the number of plants was positive in the winter seasons (R2= 0.2848) and summer (R2= 0.4383), indicating that elephants are highly selective towards areas with higher numbers of woody plants. Plant species diversity indicated no influence on dung density in winter (R2= 0.00005), but showed a negative trend in summer (R2= 0.0154). The height of canopy base was negatively related to dung density, with elephants selecting areas with a mean canopy base height between 1.5-3.0m during both winter (R2=0.2288) and summer (R2=0.174). Dung density showed a negative trend when related to canopy volume in both seasons. The R2 value for winter is 0.2087 and in summer it is 0.1471. Percent canopy cover had a negative influence on the dung densities in winter (R~= 0.083) and in summer (R2= 0.1524). NDVI showed a negative relationship with dung densities in winter (R2=0.01l1) and a positive relationship in summer (R2= 0.1894). The relationship between the standard deviation of slope and dung density showed a negative trend in both winter, (R2=0.0033) as well as in summer (R2=0.0389). The higher elevation grids show a lower d/mg density during both winter (R2=0.216) and summer (R2=O.l443). The relationship between dung density and proximity to water in winter is negative (R2=0.1575) and the relationship remains negative (R2=0.1016) in summer. In relation to nitrogen content and dung density in winter there was a weak positive trend (R2=0.0256), while in summer there was a weak negative trend (R2=0.032). The relationship between dung densities and percent acid detergent fibre (ADF) in winter indicated a weak positive trend (R2=0.0012) and during summer, indicated a weak negative trend (R2=0.0657). In relation to percentage ash content (Fig. 4.29.), dung densities in winter indicated a weak positive trend" (R2=0.0114), while in summer there was a weak negative trend (R2=0.0641). When compared with sodium, dung densities showed a very weak positive trend (R2=0.0092) in winter and a negative trend in summer (R2=0.0834). In winter, when compared with dung densities potassium showed no trend (R2=0.001), but in summer, there was a weak negative trend (R2=0.0076). In winter, calcium does not show any relationship with dung densities (R2=0.0002), while in summer, there is a weak negative trend (R2= 0.0511). Magnesium content does not show any relationship with dung densities (Fig 4.33) in the winter season, (R2=0.0007), while in summer, there is a weak negative trend (R2=0.004). Zinc shows a weak positive trend (R2=0.0298) in winter and a weak negative trend (R2=0.026) in summer. Principal component analysis of nutritional parameters indicated nine components that were influencing dung density distribution in the study area in both the seasons, and hence no single parameter influenced elephant habitat use. The study clearly indicates that the distribution of elephants in Chilla Range of Rajaji National Park is more related to abundance of woody species and proximity of water, than the nutritional content in plant species. Principal component analysis showed that there was no single parameter that influenced dung distribution in the study area. This could be due to the fact that plant species selected for foraging by elephants contained an adequate amount of nutrients in most species for meeting foraging requirements .an d they probably meet their daily requirements by foraging on varied proportions of plant species.Item Health and Sexual Signals of Male Asian Elephants (Elephas maximus) in Nagarahole National Park, Southern India(Wildlife Institute of India, Dehradun, 1999) Nath, Cheryl; Johnsingh, A.J.T.Male Asian elephants (Elephas maxim us) were studied at Nagarahole National Park, southern India from November 1998 to May 1999. Information was collected on at least 30 identified individuals for investigation of the possible use of musth and tusk length by males as signals of health and genetic fitness to female elephants. This study followed an earlier study by Watve and Sukumar (1997) which showed a significant negative correlation between tusk lengths and parasite loads in male elephants of the Mudumalai Wildlife Sanctuary, southern India. In this project, musth was studied in . addition to tusk length as a possible indicator of good health. It was hypothesised that musth and tusk length in male elephants would be related to better health and body condition and hence could potentially be considered as signals of better genetic quality, within the framework of Zahavi's theory of honest signaling (1975, 1977) and Hamilton and Zuk's theory of heritable true fitness (1982), respectively. The indicators of better health and body condition used were a subjectively scored body condition index (SCI) and a quantitative assessment of intestinal helminth parasite density (parasite load). Individuals were identified by a combination of several physical features, photographic records were obtained for height and tusk length measurement and information was collected on body condition, parasite loads, musth intensity and social interactions. The following interesting results were obtained: 1. Individuals exhibiting signs of early musth had significantly better body conditions and lower parasite loads than individuals exhibiting no signs of musth. 2. Longer tusks were not significantly correlated with better body condition, lower parasite loads or musth in this study.3. Dominance behaviours recorded in dyadic interactions among male elephants indicated that dominance was associated with musth, height of the animal and tusk length in a high percentage of interactions (100%, 89% and 78%, respectively).The significant association between early musth and better body condition as well as between early musth and reduced parasite loads indicates that male elephants may require better health in order to attain musth. Hence musth appears to be a potential honest signal of better than average health, in males which are able to attain this condition. This information may be used by female elephants in choosing mates. Social interactions among males corroborated this speculation by showing that musth and height in male elephants may be important determinants of dominance, which in tum may influence female choice and reproductive success. Limited samples of male-female interactions suggested that females discriminate between different males, and that male-male dominance interactions may influence female choice. However, small sample sizes limited the extent to which these findings could be extrapolated in this and other elephant populations.