Impacts of Management Practices on Lion and Ungulate Habitats in Gir Protected Area

Abstract

study on the impacts of management practices on lion and ungulate habitat was conducted in Gir Protected Area (PA) from June 1991 to July 1994. The Gir PA includes Gir Wildlife Sanctuary and National Park. It is situated between 20° 55' to 21° 20N and 70° *25 to 71° 15' E in the Southern part of Kathiawar peninsula in western Giijarat. Gir PA (hereafter Gir) is located about 60km South of Junagadh. The area which was 3,107 sq km in 1877 (Joshi 1976) has been presently reduced to 1,412 sq km, of which about 259 sq km is national nark. The terrain is hilly, altitude ranging from about 100m above mean sea level to 528m above mean sea level. The hills run in all directions, have moderate slopes, and constitute an important catchment for Kathiawar peninsula. The rocks are volcanic in origin, consisting of Deccan traps and are the oldest exposed rocks in Gir (Patel 1992). As many as seven types of soils have been categorized based on their colours (Munsell colour chart) ranging from dark yellowish brown to very dark greyish Brown (Pandit et al. 1992). The climate is semi-arid with three distinct seasons; summer (March-mid June), monsoon (mid June - mid October) and winter (late October to February). Gir has dry deciduous forest - 5A/Clb (Champion & Seth 1968). West Gir has Tectona grandis dominated vegetation. In eastern Gir Anogeissus pendula replaces Tectona grandis but the vegetation is dominated by thorny species such as Acacia and Zizyphus. Gir is the last refuge of the wild Asiatic lions (Panthera leo persica) and long term conservation of the Asiatic lion is an overriding management objective of Gir. In order to improve habitat conditions in Gir, the park authorities, over the last 20-25 years have made some management interventions such as relocation of some maldharis (local graziers), reduction in livestock grazing (especially migrant livestock during the rainy season) and fire control. These measures have led to vegetational improvement and increase in wild ungulate and lion populations. Understanding this vegetational improvement was thought to be crucial to determine the extent of management intervention required. The objectives of this study were: 1. to investigate the impact of maldharis on vegetation; 2. to investigate the habitat utilization by wild ungulates; and 3. to find out the impact of management practices (such as use of fire, creation of water holes, grass harvesting, maldhari relocation and creating of national park). iii The vegetation study was conducted in 211 plots of 20m X 20m each. Vegetation data included counts and measurement of trees, seedling, and shrubs. Status of trees and seedlings in terms of lopped, cut, dead or intact was recorded to study the effect of anthropogenic factors. Data on environmental variables i.e. slope and soil parameters (pH, electrical conductivity, potash, phosphorus, organic carbon, texture, moisture and water retaining capacity and colour) was collected to study their impact on the vegetation. Habitat utilization by ungulates was investigated through direct and indirect evidence. Indirect evidence included pellet group count and browse consumption. Pellets groups of chital (Cervus axis), sambar (Cervus unicolor), nilgai (Boselaphus tragocamelus), chinkara (Gazella gazelld), chowsingha (Tetracerus quadricomis) and wild pig (sus scrqfa) were counted from ten 10m X 2m belt transects in and around 100 vegetation plots. Direct count of ungulates was carried out using vehicle transects at twelve routes all over Gir in the summers of 1992, 1993 and 1994. Data on cover and animal evidence was collected in summer (April-May) and winter (December- January) of 1991,1992, and 1993. Browse consumption by ungulates was estimated on trial for few major browse species. The browse production and consumption was estimated through diameter weight relationship of twings based on linear regression. Habitat factors included were cover at 0.5m, 1.0m and 1.75m height, canopy, tree species diversity, browse availability, grass cover, leaf litter, distance from nes (hamlet), distance from water, slope and grazing by livestock. Cover was measured from five, fixed Im X lm quadrats in the 100 vegetation plots. Relationship of vegetation associations with environmental factors and ungulate abundance with habitat factors were investigated using multivariate analysis. Fifteen vegetation associations were categorized based on two way indicator species analysis (TWINSPAN) computer programme. These were: 1. Acacia catechu - Zizyphus nummularia - Aristida adscensionis 2. Apluda mutica - Themeda quadrivalvis - Sehima nervosum 3. Anogeissus latifblia-Acaciacatechu- erminaliacrenulata 4. Anogeissus latifblia - Acacia catechu 5. Acacia spp. - Zizyphus mauritiana 6. Zizyphus mauritiana 7. Acacia nilotica - Zizyphus mauritiana 8. Tectona grandis - Acacia catechu - Zizyphus mauritiana 9. Tectona grandis - Acacia catechu - Terminalia crenulata 10. Tectona grandis 11. Acacia catechu - Lannea coromandelica - Boswellia serrata 12. Tectona grandis - Acacia spp. - Wrightia tinctoria 13. Tectona grandis mixed 14. Mixed and 15. Syzygium ubicundum - Pongamiapinnata associations. iv Tree density and diversity were all maximum in Mixed association while seedling density and shrub volume were maximum in Syzygium rubicundum - Pongamia pinnata association. Soil pH, moisture and potash were important environmental factors which determined the vegetation distribution (Canonical correspondence analysis-CANOCO; P=.O5). However, different vegetation associations were governed by various environmental variables separately and just one or a combination of some variables could not explain the distribution of vegetation associations. Twelve habitat types were classified based on similarity in the vegetation associations and TWINSPAN analysis. These habitats were given a simple name and a name that represented the habitats. The following twelve habitats were categorized: 1. Scrubland 2. Savanna 3. Anogeissus - Acacia - Terminalia 4. Anogeissus - Acacia 5. Thom forest 6. Teak - Acacia - Zizyphus 7. Teak forest 8. Teak - Acacia - Boswellia 9. Teak - Acacia - Wrightia 10. Teak mixed 11. Mixed forest 12. Riverine Mixed habitat was more diverse while riverine was most dense in terms of cover. Thom forest provided maximum browse to the ungulates. Chital (Cervus axis) showed high use of Thom forest habitat while sambar (Cervus unicolor) used more Mixed, Riverine and Teak - Acacia - Zizyphus habitat. Data on other ungulates was not sufficient for statistical analysis. CANOCO showed that human disturbance governed the wild ungulate abundance in summer while ground cover and human disturbance were decisive factors in winter. Sambar and nilgai were away from disturbance while chital were relatively unaffected by disturbance, in both summer and winter. Chinkara was observed mostly in the east Gir, a place with conditions like savanna and with more human disturbance. Impacts of management practices was investigated in vegetation plots and pellet transects, and by comparing them at varying distances from nes and water points, between national paric and wildlife sanctuary, burnt and unbumt areas and between harvested and unharvested localities. Late serai stages of vegetation succession (Thomy - with Acacia and Zizyphus) were reached after 10 yrs of nes relocation and such stages were utilized more by ungulates. Impact of current neses on vegetation was severe only up to 500 m. Chital evidence were maximum, whereas sambar least, nearest a nes. The overall variation was significant only for chital both in summer and winter. There was significant variation in both summer and winter in chital evidence, not sambar, found at various distances from water holes. Maximum chital evidence were nearest the water holes whereas sambar were 1-2 km away from water. Controlled and cool fires did not change the vegetation composition and tree density significantly. Grass harvested areas produced more grass (1701±179 kg/ha) than unharvested ones (377±249 kg/ha). National park had significantly more tree density (500/ha), and less chital evidence (80 pellet groups/ha) than in wildlife sanctuary (480/ha, and 140/ha respectively). Teak thinning on an experimental basis is recommended to promote chital abundance. Water management by reviving disused wells in riverine tract, removal of at least 30 neses in a phased manner is suggested. Grass harvesting for local people and cool season rotational burning in unharvested areas are recommended.