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Conservation and management of Gir Lion Sanctuary and National Park, Gujarat, India
Biological Conservation 73 (1995) 183-188 © 1995 Elsevier Science Limited Printed in Great Britain. All rights reserved 0006-3207/95/$09.50
0006-3207(94)00107-3
ELSEVIER
CONSERVATION AND MANAGEMENT OF GIR LION SANCTUARY AND NATIONAL PARK, GUJARAT, INDIA Jamal A. Khan* Wildlife Institute of India, PO Box-18, Chandrabani, Dehradun-248 001, India (Received 4 February 1994; revised version received 11 October 1994; accepted 13 October 1994)
Raizada, 1956). It was managed for commercial exploitation of teak Tectona grandis on a 40-year rotation, which continued until 1972. It was also used for livestock grazing by local Maldhari graziers and surrounding villagers. Large tracts of forest land were cleared for human settlements and brought under cultivation, resulting in the loss of approximately 1178 km 2 of forest. A programme of research during the 1960s and 1970s studied the impact of Maldhari graziers on the Gir ecosystem (Hodd, 1969; Joslin, 1973; Berwick, 1974). It showed evidence of habitat degradation with numbers of livestock far above the carrying capacity of the forest (Berwick, 1974). Livestock were also found to represent 75% of the lions' diet and wild ungulates 25% (Joslin, 1973). The park managers then took several major conservation measures to reduce these impacts. These included moving a number of pastoral settlements (locally known as nesses) outside Gir, creation of a 258 km 2 National Park within the sanctuary limits, water-hole development, exclusion of migratory cattle and better wildlife protection. In 1987 the Wildlife Institute of India in collaboration with Gujarat Forest Department started a research project to evaluate the impact of past management and to study the existing conditions as regards vegetation, ungulates and Maldhari graziers of Gir. This paper discusses conservation and management issues following the research findings of that project.
Abstract Data on vegetation, ungulate population and status of Maldhari graziers from 1987 to 1989 were collected to assess the effect of conservation measures taken in Gir Lion Sanctuary after a programme of research in the 1970s. Line transects and road-strip counts were used for sampling vegetation and estimating population sizes of ungulate species. Eleven broad vegetation types were recognised in three management districts of Gir. Tree density (> 6 m) was higher in National Park (c. 300~ha) and Sanctuary West (c. 270~ha) than in Sanctuary East (c. llO/ha). Similar trends were observed among shrubs >1 m high. The maximum species richness and diversity was recorded in Sanctuary West and it decreased from west to east. Gir currently supports some 51,000 chital Axis axis, 2100 sambar Cervus unicolor, 600 nilgai Boselaphus tragocamelus and chinkara Gazella gazella and 400 chowsingha Tetracerous quadricornis as well as 284 lions Panthera leo persica. The conservation issues are discussed and some management actions recommended.
Keywords: Asiatic lion, conservation strategy, Gir forest, livestock grazing, management, ungulates. INTRODUCTION The Gir Lion Sanctuary and National Park (hereafter referred to as Gir) is the largest tract of natural vegetation in the Saurashtra region of Gujarat in northwest India (1412 km2). During the 19th century, the forest was recognised as an important area for the Asiatic lion Panthera leo persica, and when its endangered status was realised at the turn of the century, lion hunting was banned and a small area, the Devalia block, was declared a sanctuary in 1920. The present sanctuary was established in 1965 to protect the entire fauna and flora, and was expanded to its present size in 1974 with the primary objective of conserving the sole remaining wild population of lion in India. Prior to Independence in 1947, Gir forest was part of the Junagarh and Baroda estates. At the turn of the century, it occupied an area of 2590 km 2 (Santapau &
STUDY AREA Gir lies at 21021'-20040 ' N and 70015'-71015 ' E in the Kathiawar peninsula of Gujarat. It is divided into three management districts, i.e. Sanctuary West, Sanctuary East and central National Park (see Khan et al., 1994 for details). METHODS
Data on vegetation were collected on eight stratified random line transects totalling 48 km in length. There were three transects each in Sanctuary West and National Park and two in Sanctuary East. The vegetation was divided into four height categories: 0-1 m, 1-2 m, 2-6 m, and > 6 m and was assessed at fixed intervals of 200 m on each line transect. At every sampling point
*Present address: Conservation Ecology Research Group, Centre of Wildlife & Ornithology, Aligarh Muslim University, Aligarh-202 002, India 183
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J. A. Khan
the species and number of the 10 nearest trees (> 6 m) and 10 nearest shrubs (2-6 m) were recorded and also the distance between the 10th and 1lth individuals. The plants in height categories 0-1 m and 1-2 m were recorded in 10-m radius circular plots placed at each point with data on grazing and lopping pressure and abundance of weeds (caused by overgrazing) on a scale of 0 to 3, where 0 represented no grazing or lopping and absence of weeds. Data on ground cover (grass and herb) biomass were collected in random 1-m 2 quadrats in different areas of Sanctuary West and National Park during 1987 and 1988. Grasses and herbs, clipped to ground level in each quadrat, were oven-dried at 80°C for 24 h and weighed. Tree and shrub species densities were calculated for each sample and were added together to obtain the mean density estimated for each district, height category and confidence intervals. Plant species diversity was calculated by Shannon-Wiener function (Krebs, 1972) for each height category and management district. The scores for grazing and lopping pressure and weed abundance between three districts were compared by Kruskal-Wallis one-way analysis of variance. Ungulate populations in Gir were sampled by the road-strip count method (Hirst, 1969) to make results comparable with Berwick (1974). Four census operations were carried out during the summer of 1987, winter of 1988, winter of 1989 and summer of 1989 (details to be published elsewhere). The perpendicular distance of sightings from all the census transects were pooled and an overall density estimate was calculated for each species by Fourier Series Estimator using the program TRANSECT (Laake et al., 1979). The density estimates
were extrapolated for an area of 1008 km 2 to obtain an overall population size (+ 95% confidence limits) of each species. All Maldhari settlements in Sanctuary West and East were surveyed during 1988 to collect information on human and livestock populations. Livestock densities were calculated for each forest range and added together to obtain mean density values (+ standard error) for Sanctuary West and East. Areas of different forest ranges falling inside the boundary of National Park were excluded in estimating livestock density since no grazing is allowed there. The relationship between livestock density and chital abundance was tested by Spearman rank correlation coefficient. All statistical tests were performed following Siegel (1956). Nomenclature of trees and shrubs follows Patel (1984). RESULTS Vegetation
Table 1 lists the 11 vegetation types recognised with the use of the TWINSPAN program together with information on their topographical distribution in Gir and the characteristic tree species in the upper and middle canopy layers. The riverine woodland with Syzyguim rubicundum, Pongamia pinnata, and Manilkara hexandra is distributed along river valleys throughout Gir. The other major vegetation types present in Sanctuary West and National Park are Tectona-Acacia-Zizyphus woodland, thorn woodland, mixed valley community, Tectona-Boswellia-Sterculia woodland and mixed teak woodland. While Tectona-Acacia-Zizyphus and thorn woodlands are found on fiat areas having deep clayey
Table 1. Broad vegetation types, their distribution and characteristic tree species in Gir
Vegetation types
Distribution a
Tree species
Riverine woodland
River valleys, WG
Thorn woodland
Flat plain, WG
Syzyguirn rubicundum, Pongamia pinnata, Manilkara hexandra, Ficus benghalensis Acacia nilotica, Acacia catechu, Zizyphus mauritiana, Acacia senegal
Tectona-AcaciaZizyphus woodland
Flat plain, SW
Mixed teak woodland
Hills, CG
Mixed valley community
Valleys, WG
Tectona-BoswelliaSterculia woodland
Higher hills, SW
Tectona grandis, Boswellia serrata, Sterculia urens, Acacia catechu
Anogeissus-BoswelliaLannea woodland
Higher hills, SE
Anogeissus latifolia, Boswellia serrata, Sterculia urens, Lannea coromandelica, Acacia catechu
Lower hills, SE
Anogeissus latifolia, Acacia catechu, Terminalia crenulata, Butea monosperma Tectona grandis Acacia and Zizyphus spp., Dichrostachys cinerea Zizyphus spp. Dichrostachys cinerea
Tectona grandis, Acacia senegal Zizyphus mauritiana, Acacia nilotica Tectona grandis, Terminalia crenulata, Acacia catechu Tectona grandis, Pterocarpus marsupium, Schrebera swietenioides
Anogeissus- Terminalia
woodland Pure teak woodland Thorn savanna
Hills, SW Hills, WG
Thorn bushland
Flat, SE
WCG, whole of Gir; SW, Sanctuary West; CG, central Gir; SE, Sanctuary East.
Gir Lion Sanctuary conservation and management
185
Table 2. Tree and shrub densities (various height categories) in different districts of Gir (data at 95% confidence intervals)
District
n
Tree
Shrub 2-6 m
Shrub 1-2 m
Shrub 0-1 m
Sanctuary West National Park Sanctuary East
90 90 32
267.7 + 30.9 301 +_52.8 108.7 + 31
445.5 + 67.7 799.7 + 150 318.4 + 125.8
321.6 + 93.12 399.5 + 59.5 185 + 54.1
1038 + 322.2 766.6 + 259-7 446-6 + 171.1
Table 3. Species richness (S) and diversity index (DI) in different management districts and in various height categories in Gir
District
Sanctuary West National Park Sanctuary East
0-1 m
1-2 m
2-6 m
>6 m
S
DI
S
DI
S
DI
S
DI
49 44 25
1.20 1.24 1.05
36 32 21
1.06 1.82 1.05
43 35 32
1.25 0.99 1.70
29 25 11
1.36 0.76 0.66
soil, the Tectona-Boswellia-Sterculia and mixed teak woodlands are confined to hills and plateaus. The vegetation types exclusively present in Sanctuary East include Anogeissus-Terminalia woodland distributed on flat and undulating rocky areas and AnogeissusBoswellia-Lannea woodland on hilly land. The remaining vegetation types are degraded stages of the vegetation types mentioned above. The data on tree and shrub densities in different management districts showed significant differences in density values (Table 2). The tree (> 6 m) density was higher inside the National Park (c. 300/ha) and Sanctuary West (c. 270/ha) than in Sanctuary East (c. 110/ha). Similar trends were observed for shrubs of 2-6 m and 1-2 m. However, the density of the 0--1 m shrub class was highest in Sanctuary West. The 2-6 m and 1-2 m shrub classes are largely dominated by Helicteres isora (406/ha in the 2-6 m and 200/ha in the 1-2 m category), Holarrhena antidysenterica (82/ha in the 2-6 m and 31/ha in the 1-2 m category) and Wrightia tinctoria (75/ha in the 2-6 m and 50/ha in the 1-2 m category) inside National Park compared to Sanctuary West and East, where these categories have higher species richness of palatable species. The maximum species richness and diversity was observed in Sanctuary West and decreased from west to east (Table 3). Across different height categories, the 0-1 m shrub class had the maximum species richness. However, no such pattern was obvious for the diversity index across various height categories in different districts. The grazing pressure differed significantly between the three districts ( H = 638.8, d.f.= 2, p : < 0.001, Kruskal-Wallis test), being highest in Sanctuary East compared to West and National Park (Table 4). Similarly lopping pressure and abundance of weeds differed significantly between the districts ( H = 638.8 and 638.9, d.f. = 2 for each, p = < 0.001, Kruskall-Wallis test) and were lowest in National Park. The monsoon failed in Gir in 1987 and this was followed by an influx of 200,000 cattle from outside during late October. The peak ground cover biomass in 1987, prior to this influx, was 722 kg/ha in Sanctuary
Table 4. Average scores for grazing and lopping pressure and weed abundance in three districts of Gir
District Sanctuary West National Park Sanctuary East
Grazing pressure
Lopping pressure
Weed abundance
1.7 0.36 2.1
0.77 0-06 0.15
0-96 0.30 0-93
Table 5. Ground cover biomass (kg/ha) in Sanctuary West and National Park in Gir during 1988
Month June July August October November December
No. of quadrats
Sanctuary West Mean + SD
5 25 10 10 15 25
12 +_4 194 _+314 1130 + 187 2040 + 239 1533 + 246 1495 +_ 156
National Park Mean + SD 1545 + 1506 4260 + 984 5404 + 755 4538 + 556 3253 + 931
West. In 1988 the ground cover biomass showed striking differences between districts with peak values of 2040 kg/ha and 5404 kg/ha in Sanctuary West and National Park respectively (Table 5). Ungulate population Table 6 provides a comparison between population estimates of ungulate species estimated by road-strip counts and by the Gujarat Forest Department estimates using water-hole counts. Gir currently supports some 51,000 chital Axis axis (Erxleben), 2100 sambar Cervus unicolor (Kerr), 600 nilgai Boselaphus tragocamelus (Pallas) and chinkara Gazella gazella (Pallas), and 400 chowsingha Tetracerous quadricornis (Blainville). Maldharis and livestock population There are at present 74 Maldhari settlements in Sanctuary West and East with a livestock and human population of 13,755 and 2172, respectively. Apart from these
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J. A. Khan
Table 6. Total population estimates of different ungulate species in Gir
Species
1985 water-hole count (Forest department estimate)
1989population size (road-stripcounts)
10,466 772 2031 1063 331 2212
51,221 + 3226 2107 + 282 584 + 151 423 + 120 630 + 252 --
Chital Sambar Nilgai Chowsingha Chinkara Wild boar
Table 7. Livestock densities (no/km 2) in different forest ranges of Gir
Forest range
District
Density
Devalia Sasan Dedakadi Visavadar Chodavadi Jamvala Barbaria Hadala Jasadhar Tulsishyam Dalkhania
Sanctuary West Sanctuary West Sanctuary West Sanctuary West Sanctuary West/National Park Sanctuary West/National Park Sanctuary West/National Park Sanctuary East Sanctuary East Sanctuary East Sanctuary East
0-46 15.6 8 6.1 9.4~ 0~24~ 11.7" 23.4 27.8 25.1 8.4
"Area of National Park excluded in density estimation. settlements, there are 14 forest settlements in both districts with 3000 domestic livestock. The average household size per ness was 5.9 in Sanctuary West and 6.5 in Sanctuary East. The average number of livestock per Maldhari settlement was greater in Sanctuary East (218) compared to West (151). However, there was no significant difference in the number of cattle per household between East and West (means 23.6 and 23.1). Table 7 provides livestock densities in different forest ranges of Gir. The mean livestock density was nearly three times as high in Sanctuary East compared to West. There was no significant correlation between livestock density and chital abundance in different Gir forest ranges (rs = ~)-48, n = 9, p -- > 0.05). DISCUSSION Vegetation and ungulate population The vegetation of Gir, though previously described in terms of floristics (Santapau & Raizada, 1954, 1956) and tree species associations (Berwick, 1974), lacked a simple habitat classification. The classification of broad habitat types presented here is easily recognisable in the field on the basis of dominant tree species and their topographic distribution, and the same may now be used for overall management of vegetation and ungulate populations. The significant increase in plant density, decrease in species richness in all height categories and dominance of a few shrub species occurring in uniform patches in
height categories 1-2 m and 2-6 m inside National Park is a direct consequence of the total protection from livestock grazing and fire in the past 20 years. The increase in cover inside National Park suits the overall habitat requirements of sambar but has been largely detrimental for chital and nilgai, which prefer open areas with ample ecotones (Schaller, 1967; Dinerstein, 1980). The sambar population in Gir is only 4% of chital numbers and has not shown any significant increase since 1970 (Khan et al., 1990). Sambar represent 15% of the lions' diet (Ravi Chellam, 1993) and it is possible that this high predation is limiting the growth of the sambar population, which is therefore unlikely to increase no matter how extensive and suitable its habitat inside National Park. On the other hand, the chital represents 43% of the lions' diet (Ravi Chellam, 1993) and its population could be increased in National Park and Sanctuary East through careful habitat management, for example by creating open grasslands and ecotones in valleys and fiat areas of National Park through patch cutting, by promoting the growth of palatable Acacia and Zizyphus species and providing ample water in such areas. Similarly the dominance of a few species of shrubs is not beneficial for ungulates, and such areas require selective clearing. These management actions, however, should first be carried out on an experimental basis and their impact on vegetation and ungulates evaluated. The grass production inside National Park has improved considerably since 1970. The average ground cover biomass in 1970, obtained from seven exclosures, was 2443 kg/ha (Berwick, 1974). The figure is much lower than the 5404 kg/ha recorded in National Park. Drought years, such as 1987, result in acute shortage of grass in Gir. During normal monsoon years, a substantial amount of grass biomass remains under-utilised even after harvesting by the Forest Department, particularly in National Park. This is undesirable as very often it becomes the basis of conflict between the aspirations of local people and the conservation goals of Gir. Secondly it results in high grazing pressures in Sanctuary West and East from the livestock populations of Maldharis and surrounding villages. As a result of severe grazing, grass cover in both districts is dominated by weeds such as Cassia torn and Achyranthes aspera. The grazing policy in Gir needs to be reviewed to optimize this resource and to halt the degradation of grass cover. The diverse and palatable shrub layer in all management districts contributes much to the maintenance of a high ungulate biomass. However, this diversity may become affected by the spread of unpalatable Lantana camara as a consequence of drought-induced plant mortality (Khan eta/., 1994) and could reduce food availability for ungulates. The population estimates of ungulates by randomised road-strip counts highlight the underestimates obtained from water-hole counts; for instance, the chital number is over four times higher by the road-strip method. Managers in Gir have until now used waterhole counts at five-year intervals but the density
Gir Lion Sanctuary conservation and management
estimates obtained by this technique cannot be tested and the technique is based on a number of hypothetical assumptions (e.g. drinking frequency of ungulates). It is recommended that the census policy in Gir may be reviewed to accommodate an annual ungulate census. The road-strip counts conducted during this study may serve as a model. There has been a large increase in chital density inside Gir during the last two decades, especially inside Sanctuary West an National Park, through increased grass production and access to habitats previously occupied by livestock. However, the domestic livestock still contributes 62-9% and 82-2% to the overall ungulate biomass in Sanctuary West and East (Khan, 1993). It is therefore highly desirable that this is reduced to about 50% or less in both districts. According to a census conducted by Gujarat Forest Department in 1990, there are 284 lions in Gir. Recently they have started straying out of Gir and during 1988-90 claimed several human lives and injured scores of people. Managers have attributed this to a shortage of prey inside Gir based on the low water-hole estimates for ungulates. The lion population has grown steadily in the past and, as they are highly territorial, there is an upper limit which Gir can support. The lions which stray out of Gir do not hold territories and mostly survive in marginal habitats in terms of ungulate biomass. The practice of capturing straying lions and releasing them back in the central part of Gir has been wholly unsuccessful (B. J. Pathak, pers. comm.). Such lions would be better used in building up a captive stock of pure Asiatic lion elsewhere in India. Maldharis and livestock population Maldharis and their livestock have inhabited Gir for the last 150 years. Prior to 1972, there were 137 settlements with about 6700 Maldharis and 25,000 livestock (Berwick, 1974). Berwick did not record any competition for food between wild ungulates and domestic livestock. However, the total number of domestic livestock was thought to be well above the carrying capacity, which in 1974 led to the removal of many Maldhari settlements. The Gujarat Forest Department now plans to move all settlements outside Gir. The first programme met with very limited success and the Maldharis were not successful in adapting to stall feeding and agriculture (personal observations). The remaining Maldharis in Gir are reluctant to move. However, the present proposal is considered to have taken care of the shortcomings of the previous attempt (B. J. Pathak, pers. comm.) and it is expected that Maldharis would benefit greatly in terms of better living conditions and earnings from livestock. The Maldharis influence the Gir ecosystem by lopping and grazing. Whilst the lopping is very marginal and restricted to the dry season, the level of grazing is severe only inside Sanctuary East. The whole issue of Maldharis and livestock may therefore be viewed as a problem of regulation rather than eradication. I Consider that some biotic interference will always be
187
required in Gir to maintain suitable vegetation for ungulates, especially chital. Lopping helps by checking the browse line so that it remains within the reach of most ungulates, and disturbance favours the growth of highly palatable Acacia and Zizyphus species. Similarly, moderate grazing creates optimal grass conditions for chital (Schaller, 1967; Khan, 1994). Moreover, plant regeneration and species richness inside Gir was highest in Sanctuary West where moderate grazing still takes place. More research is needed to investigate the dynamics of grazing and lopping before further movement of Maldharis out of Gir. Managers can achieve much more, by limiting the number of livestock per settlement and relocating the Maldhari settlements from valleys and riverine forest, to achieve uniform grazing pressure. ACKNOWLEDGEMENTS Thanks are due to Mr H. S. Panwar for providing logistic and financial support to carry out research in Gir. I am greatly indebted to my supervisors Drs W. A. Rodgers, A. J. T. Johnsingh and P. K. Mathur for their valuable guidance throughout the project. I am also grateful to Gujarat Forest Department for permission and valuable suggestions from various forest officers. Dr Ajith Kumar and Rajesh Thapa are thanked for their help in data analysis. I also thank Ravi Chellam, Rashid, Afif, Ashfaque and Salim for their support. Finally thanks are due to Dr B. N. K. Davis and two anonymous referees for their valuable advice and comments on this paper. REFERENCES Berwick, S. H. (1974). The community of wild ruminants in Gir forest ecosystem. PhD dissertation, Yale University. Dinerstein, E. (1980). An ecological survey of Karnali-Bardia wildlife reserve, Nepal. Biol. Conserv., 18, 5-38. Hirst, S. M. (1969). Road-strip census techniques for wild ungulates in African woodland. J. Wildl. Manage., 33, 40-8. Hodd, K. T. B. (1969). The ecological impact of domestic livestock on the Gir forest. IUCN Tech. Mtg, 11th 259-65. Joslin, P. (1973). The Asiatic lion: a study of ecology and behaviour. PhD thesis, University of Edinburgh. Khan, J. A. (1993). Ungulate-habitat relationships in Gir forest ecosystem and its management implications. PhD thesis, Aligarh Muslim University, India. Khan, J. A. (1994). Food habits of ungulates in dry tropical forest of Gir Lion Sanctuary, Gujarat, India. Acta Theriol., 39, 185-93. Khan, J. A., Rodgers, W. A., Johnsingh, A. J. T. & Mathur, P. K. (1990). Gir Lion Project. Ungulate-habitat ecology in Gir. Wildlife Institute of India, Dehradun (unpublished report). Khan, J. A., Rodgers, W. A., Johnsingh, A. J. T. & Mathur, P. K. (1994). Tree and shrub mortality and debarking by sambar Cervus unicolor (Kerr) in Gir after a drought in Gujarat, India. Biol. Conserv., 68, 149-54. Krebs, C. J. (1972). Ecology: the experimental analysis of distribution and abundance. Harper & Row, New York. Laake, J. L., Burnham, K. P. & Anderson, D. R. (1979). User's manual for program TRANSECT. Utah State University Press, Logan.
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Patel, R. I. (1984). Forest flora of Gujarat State. Forest Department, Gujarat State, Baroda. Ravi Chellam (1993). The ecology of Asiatic lion Panthera leo persica. PhD thesis, Saurashtra University. Santapau, H. & Raizada, M. (1954). Contribution to the flora of Gir forest in Sourashtra. Ind. For., 80, 379-89.
Santapau, H. & Raizada, M. (1956). Contribution to the flora of Gir forest in Sourashtra. Ind. For. Rec. (N. S.) Bot., 40, 105-70. Schaller, G. B. (1967). Tile deer and the tiger. University of Chicago Press, Chicago. Siegel, S. (1956). Nonparametric statistics for the behavioral sciences. KOGAKUSHA, McGraw-Hill.
0006-3207(94)00107-3
ELSEVIER
CONSERVATION AND MANAGEMENT OF GIR LION SANCTUARY AND NATIONAL PARK, GUJARAT, INDIA Jamal A. Khan* Wildlife Institute of India, PO Box-18, Chandrabani, Dehradun-248 001, India (Received 4 February 1994; revised version received 11 October 1994; accepted 13 October 1994)
Raizada, 1956). It was managed for commercial exploitation of teak Tectona grandis on a 40-year rotation, which continued until 1972. It was also used for livestock grazing by local Maldhari graziers and surrounding villagers. Large tracts of forest land were cleared for human settlements and brought under cultivation, resulting in the loss of approximately 1178 km 2 of forest. A programme of research during the 1960s and 1970s studied the impact of Maldhari graziers on the Gir ecosystem (Hodd, 1969; Joslin, 1973; Berwick, 1974). It showed evidence of habitat degradation with numbers of livestock far above the carrying capacity of the forest (Berwick, 1974). Livestock were also found to represent 75% of the lions' diet and wild ungulates 25% (Joslin, 1973). The park managers then took several major conservation measures to reduce these impacts. These included moving a number of pastoral settlements (locally known as nesses) outside Gir, creation of a 258 km 2 National Park within the sanctuary limits, water-hole development, exclusion of migratory cattle and better wildlife protection. In 1987 the Wildlife Institute of India in collaboration with Gujarat Forest Department started a research project to evaluate the impact of past management and to study the existing conditions as regards vegetation, ungulates and Maldhari graziers of Gir. This paper discusses conservation and management issues following the research findings of that project.
Abstract Data on vegetation, ungulate population and status of Maldhari graziers from 1987 to 1989 were collected to assess the effect of conservation measures taken in Gir Lion Sanctuary after a programme of research in the 1970s. Line transects and road-strip counts were used for sampling vegetation and estimating population sizes of ungulate species. Eleven broad vegetation types were recognised in three management districts of Gir. Tree density (> 6 m) was higher in National Park (c. 300~ha) and Sanctuary West (c. 270~ha) than in Sanctuary East (c. llO/ha). Similar trends were observed among shrubs >1 m high. The maximum species richness and diversity was recorded in Sanctuary West and it decreased from west to east. Gir currently supports some 51,000 chital Axis axis, 2100 sambar Cervus unicolor, 600 nilgai Boselaphus tragocamelus and chinkara Gazella gazella and 400 chowsingha Tetracerous quadricornis as well as 284 lions Panthera leo persica. The conservation issues are discussed and some management actions recommended.
Keywords: Asiatic lion, conservation strategy, Gir forest, livestock grazing, management, ungulates. INTRODUCTION The Gir Lion Sanctuary and National Park (hereafter referred to as Gir) is the largest tract of natural vegetation in the Saurashtra region of Gujarat in northwest India (1412 km2). During the 19th century, the forest was recognised as an important area for the Asiatic lion Panthera leo persica, and when its endangered status was realised at the turn of the century, lion hunting was banned and a small area, the Devalia block, was declared a sanctuary in 1920. The present sanctuary was established in 1965 to protect the entire fauna and flora, and was expanded to its present size in 1974 with the primary objective of conserving the sole remaining wild population of lion in India. Prior to Independence in 1947, Gir forest was part of the Junagarh and Baroda estates. At the turn of the century, it occupied an area of 2590 km 2 (Santapau &
STUDY AREA Gir lies at 21021'-20040 ' N and 70015'-71015 ' E in the Kathiawar peninsula of Gujarat. It is divided into three management districts, i.e. Sanctuary West, Sanctuary East and central National Park (see Khan et al., 1994 for details). METHODS
Data on vegetation were collected on eight stratified random line transects totalling 48 km in length. There were three transects each in Sanctuary West and National Park and two in Sanctuary East. The vegetation was divided into four height categories: 0-1 m, 1-2 m, 2-6 m, and > 6 m and was assessed at fixed intervals of 200 m on each line transect. At every sampling point
*Present address: Conservation Ecology Research Group, Centre of Wildlife & Ornithology, Aligarh Muslim University, Aligarh-202 002, India 183
184
J. A. Khan
the species and number of the 10 nearest trees (> 6 m) and 10 nearest shrubs (2-6 m) were recorded and also the distance between the 10th and 1lth individuals. The plants in height categories 0-1 m and 1-2 m were recorded in 10-m radius circular plots placed at each point with data on grazing and lopping pressure and abundance of weeds (caused by overgrazing) on a scale of 0 to 3, where 0 represented no grazing or lopping and absence of weeds. Data on ground cover (grass and herb) biomass were collected in random 1-m 2 quadrats in different areas of Sanctuary West and National Park during 1987 and 1988. Grasses and herbs, clipped to ground level in each quadrat, were oven-dried at 80°C for 24 h and weighed. Tree and shrub species densities were calculated for each sample and were added together to obtain the mean density estimated for each district, height category and confidence intervals. Plant species diversity was calculated by Shannon-Wiener function (Krebs, 1972) for each height category and management district. The scores for grazing and lopping pressure and weed abundance between three districts were compared by Kruskal-Wallis one-way analysis of variance. Ungulate populations in Gir were sampled by the road-strip count method (Hirst, 1969) to make results comparable with Berwick (1974). Four census operations were carried out during the summer of 1987, winter of 1988, winter of 1989 and summer of 1989 (details to be published elsewhere). The perpendicular distance of sightings from all the census transects were pooled and an overall density estimate was calculated for each species by Fourier Series Estimator using the program TRANSECT (Laake et al., 1979). The density estimates
were extrapolated for an area of 1008 km 2 to obtain an overall population size (+ 95% confidence limits) of each species. All Maldhari settlements in Sanctuary West and East were surveyed during 1988 to collect information on human and livestock populations. Livestock densities were calculated for each forest range and added together to obtain mean density values (+ standard error) for Sanctuary West and East. Areas of different forest ranges falling inside the boundary of National Park were excluded in estimating livestock density since no grazing is allowed there. The relationship between livestock density and chital abundance was tested by Spearman rank correlation coefficient. All statistical tests were performed following Siegel (1956). Nomenclature of trees and shrubs follows Patel (1984). RESULTS Vegetation
Table 1 lists the 11 vegetation types recognised with the use of the TWINSPAN program together with information on their topographical distribution in Gir and the characteristic tree species in the upper and middle canopy layers. The riverine woodland with Syzyguim rubicundum, Pongamia pinnata, and Manilkara hexandra is distributed along river valleys throughout Gir. The other major vegetation types present in Sanctuary West and National Park are Tectona-Acacia-Zizyphus woodland, thorn woodland, mixed valley community, Tectona-Boswellia-Sterculia woodland and mixed teak woodland. While Tectona-Acacia-Zizyphus and thorn woodlands are found on fiat areas having deep clayey
Table 1. Broad vegetation types, their distribution and characteristic tree species in Gir
Vegetation types
Distribution a
Tree species
Riverine woodland
River valleys, WG
Thorn woodland
Flat plain, WG
Syzyguirn rubicundum, Pongamia pinnata, Manilkara hexandra, Ficus benghalensis Acacia nilotica, Acacia catechu, Zizyphus mauritiana, Acacia senegal
Tectona-AcaciaZizyphus woodland
Flat plain, SW
Mixed teak woodland
Hills, CG
Mixed valley community
Valleys, WG
Tectona-BoswelliaSterculia woodland
Higher hills, SW
Tectona grandis, Boswellia serrata, Sterculia urens, Acacia catechu
Anogeissus-BoswelliaLannea woodland
Higher hills, SE
Anogeissus latifolia, Boswellia serrata, Sterculia urens, Lannea coromandelica, Acacia catechu
Lower hills, SE
Anogeissus latifolia, Acacia catechu, Terminalia crenulata, Butea monosperma Tectona grandis Acacia and Zizyphus spp., Dichrostachys cinerea Zizyphus spp. Dichrostachys cinerea
Tectona grandis, Acacia senegal Zizyphus mauritiana, Acacia nilotica Tectona grandis, Terminalia crenulata, Acacia catechu Tectona grandis, Pterocarpus marsupium, Schrebera swietenioides
Anogeissus- Terminalia
woodland Pure teak woodland Thorn savanna
Hills, SW Hills, WG
Thorn bushland
Flat, SE
WCG, whole of Gir; SW, Sanctuary West; CG, central Gir; SE, Sanctuary East.
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Table 2. Tree and shrub densities (various height categories) in different districts of Gir (data at 95% confidence intervals)
District
n
Tree
Shrub 2-6 m
Shrub 1-2 m
Shrub 0-1 m
Sanctuary West National Park Sanctuary East
90 90 32
267.7 + 30.9 301 +_52.8 108.7 + 31
445.5 + 67.7 799.7 + 150 318.4 + 125.8
321.6 + 93.12 399.5 + 59.5 185 + 54.1
1038 + 322.2 766.6 + 259-7 446-6 + 171.1
Table 3. Species richness (S) and diversity index (DI) in different management districts and in various height categories in Gir
District
Sanctuary West National Park Sanctuary East
0-1 m
1-2 m
2-6 m
>6 m
S
DI
S
DI
S
DI
S
DI
49 44 25
1.20 1.24 1.05
36 32 21
1.06 1.82 1.05
43 35 32
1.25 0.99 1.70
29 25 11
1.36 0.76 0.66
soil, the Tectona-Boswellia-Sterculia and mixed teak woodlands are confined to hills and plateaus. The vegetation types exclusively present in Sanctuary East include Anogeissus-Terminalia woodland distributed on flat and undulating rocky areas and AnogeissusBoswellia-Lannea woodland on hilly land. The remaining vegetation types are degraded stages of the vegetation types mentioned above. The data on tree and shrub densities in different management districts showed significant differences in density values (Table 2). The tree (> 6 m) density was higher inside the National Park (c. 300/ha) and Sanctuary West (c. 270/ha) than in Sanctuary East (c. 110/ha). Similar trends were observed for shrubs of 2-6 m and 1-2 m. However, the density of the 0--1 m shrub class was highest in Sanctuary West. The 2-6 m and 1-2 m shrub classes are largely dominated by Helicteres isora (406/ha in the 2-6 m and 200/ha in the 1-2 m category), Holarrhena antidysenterica (82/ha in the 2-6 m and 31/ha in the 1-2 m category) and Wrightia tinctoria (75/ha in the 2-6 m and 50/ha in the 1-2 m category) inside National Park compared to Sanctuary West and East, where these categories have higher species richness of palatable species. The maximum species richness and diversity was observed in Sanctuary West and decreased from west to east (Table 3). Across different height categories, the 0-1 m shrub class had the maximum species richness. However, no such pattern was obvious for the diversity index across various height categories in different districts. The grazing pressure differed significantly between the three districts ( H = 638.8, d.f.= 2, p : < 0.001, Kruskal-Wallis test), being highest in Sanctuary East compared to West and National Park (Table 4). Similarly lopping pressure and abundance of weeds differed significantly between the districts ( H = 638.8 and 638.9, d.f. = 2 for each, p = < 0.001, Kruskall-Wallis test) and were lowest in National Park. The monsoon failed in Gir in 1987 and this was followed by an influx of 200,000 cattle from outside during late October. The peak ground cover biomass in 1987, prior to this influx, was 722 kg/ha in Sanctuary
Table 4. Average scores for grazing and lopping pressure and weed abundance in three districts of Gir
District Sanctuary West National Park Sanctuary East
Grazing pressure
Lopping pressure
Weed abundance
1.7 0.36 2.1
0.77 0-06 0.15
0-96 0.30 0-93
Table 5. Ground cover biomass (kg/ha) in Sanctuary West and National Park in Gir during 1988
Month June July August October November December
No. of quadrats
Sanctuary West Mean + SD
5 25 10 10 15 25
12 +_4 194 _+314 1130 + 187 2040 + 239 1533 + 246 1495 +_ 156
National Park Mean + SD 1545 + 1506 4260 + 984 5404 + 755 4538 + 556 3253 + 931
West. In 1988 the ground cover biomass showed striking differences between districts with peak values of 2040 kg/ha and 5404 kg/ha in Sanctuary West and National Park respectively (Table 5). Ungulate population Table 6 provides a comparison between population estimates of ungulate species estimated by road-strip counts and by the Gujarat Forest Department estimates using water-hole counts. Gir currently supports some 51,000 chital Axis axis (Erxleben), 2100 sambar Cervus unicolor (Kerr), 600 nilgai Boselaphus tragocamelus (Pallas) and chinkara Gazella gazella (Pallas), and 400 chowsingha Tetracerous quadricornis (Blainville). Maldharis and livestock population There are at present 74 Maldhari settlements in Sanctuary West and East with a livestock and human population of 13,755 and 2172, respectively. Apart from these
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J. A. Khan
Table 6. Total population estimates of different ungulate species in Gir
Species
1985 water-hole count (Forest department estimate)
1989population size (road-stripcounts)
10,466 772 2031 1063 331 2212
51,221 + 3226 2107 + 282 584 + 151 423 + 120 630 + 252 --
Chital Sambar Nilgai Chowsingha Chinkara Wild boar
Table 7. Livestock densities (no/km 2) in different forest ranges of Gir
Forest range
District
Density
Devalia Sasan Dedakadi Visavadar Chodavadi Jamvala Barbaria Hadala Jasadhar Tulsishyam Dalkhania
Sanctuary West Sanctuary West Sanctuary West Sanctuary West Sanctuary West/National Park Sanctuary West/National Park Sanctuary West/National Park Sanctuary East Sanctuary East Sanctuary East Sanctuary East
0-46 15.6 8 6.1 9.4~ 0~24~ 11.7" 23.4 27.8 25.1 8.4
"Area of National Park excluded in density estimation. settlements, there are 14 forest settlements in both districts with 3000 domestic livestock. The average household size per ness was 5.9 in Sanctuary West and 6.5 in Sanctuary East. The average number of livestock per Maldhari settlement was greater in Sanctuary East (218) compared to West (151). However, there was no significant difference in the number of cattle per household between East and West (means 23.6 and 23.1). Table 7 provides livestock densities in different forest ranges of Gir. The mean livestock density was nearly three times as high in Sanctuary East compared to West. There was no significant correlation between livestock density and chital abundance in different Gir forest ranges (rs = ~)-48, n = 9, p -- > 0.05). DISCUSSION Vegetation and ungulate population The vegetation of Gir, though previously described in terms of floristics (Santapau & Raizada, 1954, 1956) and tree species associations (Berwick, 1974), lacked a simple habitat classification. The classification of broad habitat types presented here is easily recognisable in the field on the basis of dominant tree species and their topographic distribution, and the same may now be used for overall management of vegetation and ungulate populations. The significant increase in plant density, decrease in species richness in all height categories and dominance of a few shrub species occurring in uniform patches in
height categories 1-2 m and 2-6 m inside National Park is a direct consequence of the total protection from livestock grazing and fire in the past 20 years. The increase in cover inside National Park suits the overall habitat requirements of sambar but has been largely detrimental for chital and nilgai, which prefer open areas with ample ecotones (Schaller, 1967; Dinerstein, 1980). The sambar population in Gir is only 4% of chital numbers and has not shown any significant increase since 1970 (Khan et al., 1990). Sambar represent 15% of the lions' diet (Ravi Chellam, 1993) and it is possible that this high predation is limiting the growth of the sambar population, which is therefore unlikely to increase no matter how extensive and suitable its habitat inside National Park. On the other hand, the chital represents 43% of the lions' diet (Ravi Chellam, 1993) and its population could be increased in National Park and Sanctuary East through careful habitat management, for example by creating open grasslands and ecotones in valleys and fiat areas of National Park through patch cutting, by promoting the growth of palatable Acacia and Zizyphus species and providing ample water in such areas. Similarly the dominance of a few species of shrubs is not beneficial for ungulates, and such areas require selective clearing. These management actions, however, should first be carried out on an experimental basis and their impact on vegetation and ungulates evaluated. The grass production inside National Park has improved considerably since 1970. The average ground cover biomass in 1970, obtained from seven exclosures, was 2443 kg/ha (Berwick, 1974). The figure is much lower than the 5404 kg/ha recorded in National Park. Drought years, such as 1987, result in acute shortage of grass in Gir. During normal monsoon years, a substantial amount of grass biomass remains under-utilised even after harvesting by the Forest Department, particularly in National Park. This is undesirable as very often it becomes the basis of conflict between the aspirations of local people and the conservation goals of Gir. Secondly it results in high grazing pressures in Sanctuary West and East from the livestock populations of Maldharis and surrounding villages. As a result of severe grazing, grass cover in both districts is dominated by weeds such as Cassia torn and Achyranthes aspera. The grazing policy in Gir needs to be reviewed to optimize this resource and to halt the degradation of grass cover. The diverse and palatable shrub layer in all management districts contributes much to the maintenance of a high ungulate biomass. However, this diversity may become affected by the spread of unpalatable Lantana camara as a consequence of drought-induced plant mortality (Khan eta/., 1994) and could reduce food availability for ungulates. The population estimates of ungulates by randomised road-strip counts highlight the underestimates obtained from water-hole counts; for instance, the chital number is over four times higher by the road-strip method. Managers in Gir have until now used waterhole counts at five-year intervals but the density
Gir Lion Sanctuary conservation and management
estimates obtained by this technique cannot be tested and the technique is based on a number of hypothetical assumptions (e.g. drinking frequency of ungulates). It is recommended that the census policy in Gir may be reviewed to accommodate an annual ungulate census. The road-strip counts conducted during this study may serve as a model. There has been a large increase in chital density inside Gir during the last two decades, especially inside Sanctuary West an National Park, through increased grass production and access to habitats previously occupied by livestock. However, the domestic livestock still contributes 62-9% and 82-2% to the overall ungulate biomass in Sanctuary West and East (Khan, 1993). It is therefore highly desirable that this is reduced to about 50% or less in both districts. According to a census conducted by Gujarat Forest Department in 1990, there are 284 lions in Gir. Recently they have started straying out of Gir and during 1988-90 claimed several human lives and injured scores of people. Managers have attributed this to a shortage of prey inside Gir based on the low water-hole estimates for ungulates. The lion population has grown steadily in the past and, as they are highly territorial, there is an upper limit which Gir can support. The lions which stray out of Gir do not hold territories and mostly survive in marginal habitats in terms of ungulate biomass. The practice of capturing straying lions and releasing them back in the central part of Gir has been wholly unsuccessful (B. J. Pathak, pers. comm.). Such lions would be better used in building up a captive stock of pure Asiatic lion elsewhere in India. Maldharis and livestock population Maldharis and their livestock have inhabited Gir for the last 150 years. Prior to 1972, there were 137 settlements with about 6700 Maldharis and 25,000 livestock (Berwick, 1974). Berwick did not record any competition for food between wild ungulates and domestic livestock. However, the total number of domestic livestock was thought to be well above the carrying capacity, which in 1974 led to the removal of many Maldhari settlements. The Gujarat Forest Department now plans to move all settlements outside Gir. The first programme met with very limited success and the Maldharis were not successful in adapting to stall feeding and agriculture (personal observations). The remaining Maldharis in Gir are reluctant to move. However, the present proposal is considered to have taken care of the shortcomings of the previous attempt (B. J. Pathak, pers. comm.) and it is expected that Maldharis would benefit greatly in terms of better living conditions and earnings from livestock. The Maldharis influence the Gir ecosystem by lopping and grazing. Whilst the lopping is very marginal and restricted to the dry season, the level of grazing is severe only inside Sanctuary East. The whole issue of Maldharis and livestock may therefore be viewed as a problem of regulation rather than eradication. I Consider that some biotic interference will always be
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required in Gir to maintain suitable vegetation for ungulates, especially chital. Lopping helps by checking the browse line so that it remains within the reach of most ungulates, and disturbance favours the growth of highly palatable Acacia and Zizyphus species. Similarly, moderate grazing creates optimal grass conditions for chital (Schaller, 1967; Khan, 1994). Moreover, plant regeneration and species richness inside Gir was highest in Sanctuary West where moderate grazing still takes place. More research is needed to investigate the dynamics of grazing and lopping before further movement of Maldharis out of Gir. Managers can achieve much more, by limiting the number of livestock per settlement and relocating the Maldhari settlements from valleys and riverine forest, to achieve uniform grazing pressure. ACKNOWLEDGEMENTS Thanks are due to Mr H. S. Panwar for providing logistic and financial support to carry out research in Gir. I am greatly indebted to my supervisors Drs W. A. Rodgers, A. J. T. Johnsingh and P. K. Mathur for their valuable guidance throughout the project. I am also grateful to Gujarat Forest Department for permission and valuable suggestions from various forest officers. Dr Ajith Kumar and Rajesh Thapa are thanked for their help in data analysis. I also thank Ravi Chellam, Rashid, Afif, Ashfaque and Salim for their support. Finally thanks are due to Dr B. N. K. Davis and two anonymous referees for their valuable advice and comments on this paper. REFERENCES Berwick, S. H. (1974). The community of wild ruminants in Gir forest ecosystem. PhD dissertation, Yale University. Dinerstein, E. (1980). An ecological survey of Karnali-Bardia wildlife reserve, Nepal. Biol. Conserv., 18, 5-38. Hirst, S. M. (1969). Road-strip census techniques for wild ungulates in African woodland. J. Wildl. Manage., 33, 40-8. Hodd, K. T. B. (1969). The ecological impact of domestic livestock on the Gir forest. IUCN Tech. Mtg, 11th 259-65. Joslin, P. (1973). The Asiatic lion: a study of ecology and behaviour. PhD thesis, University of Edinburgh. Khan, J. A. (1993). Ungulate-habitat relationships in Gir forest ecosystem and its management implications. PhD thesis, Aligarh Muslim University, India. Khan, J. A. (1994). Food habits of ungulates in dry tropical forest of Gir Lion Sanctuary, Gujarat, India. Acta Theriol., 39, 185-93. Khan, J. A., Rodgers, W. A., Johnsingh, A. J. T. & Mathur, P. K. (1990). Gir Lion Project. Ungulate-habitat ecology in Gir. Wildlife Institute of India, Dehradun (unpublished report). Khan, J. A., Rodgers, W. A., Johnsingh, A. J. T. & Mathur, P. K. (1994). Tree and shrub mortality and debarking by sambar Cervus unicolor (Kerr) in Gir after a drought in Gujarat, India. Biol. Conserv., 68, 149-54. Krebs, C. J. (1972). Ecology: the experimental analysis of distribution and abundance. Harper & Row, New York. Laake, J. L., Burnham, K. P. & Anderson, D. R. (1979). User's manual for program TRANSECT. Utah State University Press, Logan.
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Patel, R. I. (1984). Forest flora of Gujarat State. Forest Department, Gujarat State, Baroda. Ravi Chellam (1993). The ecology of Asiatic lion Panthera leo persica. PhD thesis, Saurashtra University. Santapau, H. & Raizada, M. (1954). Contribution to the flora of Gir forest in Sourashtra. Ind. For., 80, 379-89.
Santapau, H. & Raizada, M. (1956). Contribution to the flora of Gir forest in Sourashtra. Ind. For. Rec. (N. S.) Bot., 40, 105-70. Schaller, G. B. (1967). Tile deer and the tiger. University of Chicago Press, Chicago. Siegel, S. (1956). Nonparametric statistics for the behavioral sciences. KOGAKUSHA, McGraw-Hill.