Biological Conservation 89 (1999) 113±120

Tiger decline caused by the reduction of large ungulate prey: evidence from a study of leopard diets in southern India

Uma Ramakrishnan, Richard G. Coss *, Neil W. Pelkey Psychology Department and Graduate Group in Ecology, University of California, Davis, CA 95616, USA

Received 13 August 1998; received in revised form 24 November 1998; accepted 4 December 1998

Abstract Populations of leopards and tigers in the Kalakad-Mundanthurai Tiger Reserve, India, appear to be declining. To identify the cause of this decline, we examined the diets and the relative densities of leopards and tigers, comparing scat from this park with that from the Mudumalai Wildlife Sanctuary, a park known to have high leopard and tiger densities. Results suggested that the leopard density in Mudumalai was approximately twice that in Mundanthurai. No evidence of tigers was found in Mundanthurai. Prey species found in leopard diets in the two parks was similar; albeit, mean prey weight and the proportion of large ungulates were markedly lower in the Mundanthurai leopard diet. These dietary di€erences are consistent with the infrequent sightings of large ungulates in Mundanthurai. Analyses of satellite data revealed that large areas of grazing land in Mundanthurai have shifted to thicket, reducing available forage for large ungulates. Since large ungulates constitute important tiger prey, the low density of ungulates in Mundanthurai might explain the apparent absence of tigers. Our ®ndings suggest that the tiger population in the Kalakad-Mundanthurai Tiger Reserve could be enhanced via the application of habitat management for large ungulates. # 1999 Elsevier Science Ltd. All rights reserved.

Keywords: Conservation; Habitat management; Scat analysis; Leopard; Tiger

1. Introduction (Karanth, 1987; Sunquist and Sunquist, 1989). Though facing the same threats, leopards (Panthera pardus) are The tiger (Panthera tigris) has been classi®ed as more successful than tigers, largely because of their endangered by the IUCN, with about 6000±8000 sur- ability to live in di€erent environments and the ¯exiblity viving in the wild (Nowak, 1991). The major threat to in their diet (Bailey, 1993). The wide geographic dis- its survival is habitat loss and the poaching of tigers and tribution of leopards is also attributed to their ability to their prey (Nowell and Jackson, 1996). India supports coexist with other large carnivores (Bailey, 1993). Both the largest numbers of tigers in the wild, approximately tigers and leopards are solitary, stealth predators. Tigers two thirds of the world's tiger population (Sunquist and are usually restricted to the core areas of protected Shah, 1997). The most recent survey estimated the reserves and avoid areas of moderate to heavy human number of tigers throughout India at 3750 (Ghosh, disturbance. They are dependent on dense vegetative 1994). Their distribution in southern India is shown in cover and access to water (Nowell and Jackson, 1996). Fig. 1A. Tiger densities in the wild increased moderately in the 1980s because of intensive e€orts to protect the 1.1. Recent habitat changes in the Kalakad- species with the establishment of reserves targeted for Mundanthurai Tiger Reserve tigers in India (Karanth, 1987; Panwar, 1987). This e€ort led to the rapid increase in prey populations with The Mundanthurai sanctuary was classi®ed as a tiger a corresponding increase in tiger populations (Sunquist, reserve in 1988 because of the occurrence of tiger sight- 1996). More speci®cally, tiger densities increased with ings and other tiger evidence. However, in the last 2 the availability of large ungulate prey in the region years, there have been very few sightings of tigers (For- est Department records). Some major changes in habitat management have occurred in Mundanthurai over the * Corresponding author. Tel.: +1-530-7521626; fax: +1-530- last decade; the frequency and intensity of forest ®res 7522087; e-mail: [email protected]. were controlled and cattle were excluded from most

0006-3207/99/$ - see front matter # 1999 Elsevier Science Ltd. All rights reserved. PII: S0006-3207(98)00159-1 114 U. Ramakrishnan et al. / Biological Conservation 89 (1999) 113±120

Fig. 1. Distribution of tigers in southern India (A). Study sites for the collection of tiger and leopard scat on the Mundanthurai Plateau (B) within the Kalakad-Mundanthurai Tiger Reserve and within the Mudumalai Wildlife Sanctuary (C). areas of the park. These factors led to the decline of the diet of leopards and tigers in the Kalakad-Mun- grasslands available for herbivores. The reduction in danthurai Tiger Reserve with a region known for its forest ®res led to an increase in unpalatable exotic healthy carnivore population, the Mudumalai Wildlife thickets, such as lantana (Lantana camara) and eupa- Sanctuary. When the key item of a carnivores' diet is in torium (Eupatorium glandulosum). Although important short supply, the carnivore species will either alter its for forest management, the sudden removal of cattle diet or exhibit a drop in population size. A comparison from areas in the park coupled with ®re control aug- of carnivore densities and diets in these two wildlife mented the growth of these exotic weeds. At present, parks will shed light on which of these two e€ects have no systematic research has examined the e€ects of occurred. Previous studies on the diets of sympatric declining grazing lands on herbivore populations in this leopards and tigers have shown that their diets are very park. similar when prey are abundant (Schaller, 1967; John- A number of studies have been conducted on large singh, 1983; Karanth and Sunquist, 1995). However, carnivore species in southern India (Johnsingh, 1983; leopards tend to be more ¯exible in their diets than Karanth and Sunquist, 1995; Rice, 1986; Venkataraman tigers under deteriorating habitat conditions (John- et al., 1995). These studies were designed to obtain singh, 1983). It is reasonable to predict that a shift in the information on predator distribution and diet in a given diet of leopards toward smaller prey is an indication of park or reserve. The current study focused on comparing the low availability of larger prey favored by tigers. U. Ramakrishnan et al. / Biological Conservation 89 (1999) 113±120 115

2. Study sites and methods To create permanent slides for species identi®cation, ®ve hairs were selected randomly from each sample, Data collection was conducted from March to centered parallel on the slide, and mounted with cover September, 1997 at two study sites. The Kalakad- slip using DPX mount. Five slides were made per scat Mundanthurai Tiger Reserve is located between 8 250± sample (n ˆ 25 hairs/sample). Slides were examined at 8 530 N latitude and 77 100±77 350 E longitude, and 400X using an Olympus microscope. For identi®cation covers an area of 817 km2 (Fig. 1B). The habitat type of scat hairs, a set of reference slides was made from consists of moist evergreen rain forest, moist and dry captive prey species, museum specimens, and leopard deciduous forest, and scrub forest. Our sampling was kills. For statistical quanti®cation, each species found in restricted to the Mundanthurai Plateau and occurred one scat sample was assumed to characterize a single over multiple paths, totaling a 48.3-km distance. The predatory event. Di€erence of proportions tests were habitat type of the plateau is classi®ed as mixed decid- conducted to compare diets between parks using NCSS uous (Ali, 1981). statistical software (Hintze, 1987). The Mudumalai Wildlife Sanctuary is located Apart from scat collection, the presence of tigers and between 11 320±11 430 N latitude and 76 220±76 450 E leopards during the entire study was recorded by direct longitude and covers an area of 321 km2 (Fig. 1C). This sightings, both by researchers and local residents, and park has a variety of vegetation types, consisting of the presence of tiger and leopard pug marks and tropical semi-evergreen forest, moist and dry deciduous scrapes. Sightings by local residents living in Mun- forest, and dry thorn forest (Sukumar et al., 1992). Our danthurai were recorded through an oral interview sampling was restricted to moist and dry deciduous using a formal questionnaire to quantify evidence of forest areas and occurred over multiple paths, totaling a predation on domesticated animals. The settlements 46.7-km distance. selected for study were ®ve separate tribal colonies, two These two forest sites are part of a complex classi®ed at the edge of the park and three in the forest interior. as ``high-priority'' tiger conservation sites, which a€ord One adult per household was interviewed (n ˆ 58). the highest probability of long-term persistence of tiger Although we did not attempt to estimate prey den- populations (Wikramanayake et al., 1998). Both study sities in the two parks, we recorded all sightings of chital sites have very similar mammalian species. The large deer while collecting scat throughout the parks. Because carnivores include the leopard, tiger, wild dog (Cuon the density of herbivore prey is a€ected by habitat pre- alpinus), and striped hyena (Hyaena hyaena). Prey spe- ferences (Eisenberg and Seidensticker, 1976), we also cies also appears to be similar in the two parks (Forest estimated changes in grass cover available for grazing in Department records). the two parks. Satellite data with a 1-km2 resolution The hair of prey is relatively undamaged in carnivore from the NOAA Advanced Very High Resolution scat and can thus be used to identify the prey species Radiometer was used to measure changes in grazing land eaten. We collected leopard and tiger scat from multiple between 1986 and 1996. This data set was produced by established forest paths. Each path was sampled once a the National Institute for Environmental Studies of the month for 5 months. This period covered two seasons, a Environment Agency of Japan. It consisted of cloud- dry and a wet season. Since leopards and tigers are more free digital maps for the dry season (January±March) of likely to defecate on forest paths or on grassy areas just each year. The lea¯ess deciduous trees during the dry bordering the paths (Sunquist, 1981; Johnsingh, 1983; season permitted the detection of ground cover other- Norton et al., 1986; Karanth and Sunquist, 1995), only wise occluded by forest canopy. Each digital map used forest paths were searched. Excess scat was removed for quanti®cation was developed by mosaicking several from the paths to prevent repeated sampling at the next radiometer scenes in order to obtain a cloud-free image sampling period. The samples were sealed in plastic (see Pelkey, 1997). The vegetation index was computed bags and labeled for path location and date. Tiger scat from the ®nal image, which characterized the wide- was distinguished from leopard scat by pug marks and range distribution of vegetative conditions. We calcu- size of scat. A full-grown leopard is about one fourth lated grazing land by coding areas with the Calibrated the size of a full-grown tiger (Seidensticker, 1976), thus Vegetation Index (Kidwell, 1991), using 100±120 as the producing identi®ably smaller scat. Although it is pos- index for the grass category and >120 as the index for sible that scat from a tiger cub less than six months of thicket or forest (Goetz, 1997; Pelkey, 1997). We com- age could be misclassi®ed as leopard scat, it would con- pared only the 1986 and 1996 dry season data. stitute a very small fraction of our sample. The scat samples were washed in water using a 1.5 mm sieve to separate the hair from other organic matter. Separated 3. Results hair was then washed in hot water to remove surface oil. Each scat sample was washed separately in acetone and The leopard and tiger evidence collected in the two dehydrated in 100% ethanol. parks during this study are summarized in Table 1. 116 U. Ramakrishnan et al. / Biological Conservation 89 (1999) 113±120

Table 1 Evidence of leopards and tigers collected in the Mudumalai Wildlife Sanctuary and on the Mundanthurai Plateau

Mudumalai Mundanthurai

Tiger sightings 3 0 Tiger scat 9 0 Tiger pug marks 6 0 Leopard sightings 2 2 Leopard scat 185 111 Leopard pug marks 16 9

There was no evidence of tigers in the Kalakad-Mun- danthurai Tiger Reserve during the study period, either observed directly or reported during the interviews. In Mudumalai, 9 tiger scats were collected, 6 of which contained evidence of chital deer (Axis axis)and3of sambar deer (Cervus unicolor). Leopards, though not as common in Mundanthurai as in Mudumalai, were sighted twice in each park; 111 scat samples were col- lected in Mundanthurai compared with 185 scat sam- ples collected in Mudumalai. The proportion of prey species in the diet of leopards in the two regions appears in Fig. 2. The chital deer is the primary prey species in both regions, contributing over 50% of the leopard's diet in Mudumalai. The number of di€erent species that leopards fed upon did not di€er appreciably between the two regions. Di€er- ence of proportions tests, comparing the contribution of each prey type to the diet of leopards in the two regions, revealed that 6 species were signi®cantly di€erent in the two regions (Table 2). Of the 6 species that di€ered sig- ni®cantly using two-tailed tests ( ˆ 0:05), 5 were small species. The black-napped hare (Lepus nigricollis), rat (Rattus rattus), pangolin (Manis crassicaudata), munjac deer (Muntiacus muntjak), and porcupine (Hystrix indica) were markedly more abundant in the Mun- danthurai leopard diet (p < 0:025). The sixth species that di€ered was the chital deer, which contributed to Fig. 2. Proportional contribution of prey to the leopard diet at the 67.2% of the leopard diet in Mudumalai, but only two study sites. 24.3% in Mundanthurai (p < 0:0001). Because the emphasis herein is the comparison of the contribution of the same prey species in the leopard diet between munjac deer, Nilgiri langur (Trachypithecus johnii) and parks, the relationship of prey body size to overall diet Hanuman langur (Semnopithecus entellus); (2) 21±50 contribution will not be addressed. This is in contrast kgÐchital deer, wild boar (Sus Scrofa); (3) >50 kgÐ with Norton et al. (1986) who examined the dietary domestic cattle (Bos taurus), sambar deer, Indian bison/ contribution of prey within a single park. gaur (Bos gaurus). The contribution of each of these To generalize our ®ndings of park di€erences to other weight classes to the leopard diet from four parks in the parks in southern India, we compared our data with region is shown in Fig. 3. The proportion of heavy prey recent data from Nagarhole National Park, n ˆ 459 scat (>50 kg) did not di€er appreciably in the four parks. samples (Karanth and Sunquist, 1995) and Bandipur However, a di€erence of proportions test illustrates the National Park, n ˆ 76 scat samples (Johnsingh, 1983). highest proportion of small prey (0±20 kg) selected by Leopard prey species were categorized into the follow- leopards in Mundanthurai compared with each of the ing three body weight classes: (1) 0±20 kgÐblack nap- other three parks (p < 0:01). In contrast, the medium- ped hare, rat, pangolin, bonnet macaque (Macaca sized prey class (21±50 kg) was signi®cantly lower in radiata), porcupine, domestic dog (Canis familiaris), Mundanthurai than the other three parks (p < 0:01). U. Ramakrishnan et al. / Biological Conservation 89 (1999) 113±120 117

Table 2 A total of 48.3 km distance was surveyed per month Di€erence of proportions tests, comparing the proportion of prey hair in Mundanthurai and 46.7 km distance in Mudumalai. found in leopard scat in the Mudumalai Wildlife Sanctuary and on the The density of leopard scats in Mundanthurai was 0.87 Mundanthurai Plateau scats/km and 1.31 scats/km in Mudumalai. Thus, Species Mudumalai Mundanthurai Z-valuesa p< assuming that scat density is correlated with leopard (% of total) (% of total) density, the density of leopards in Mudumalai appears Black napped hare 3.35 13.89 3.3208 0.0001 to be almost twice as high as in Mundanthurai. Chital deer 67.22 24.32 7.1102 0.0001 Recorded sightings of chital herds from the randomly Domestic dog 2.79 6.48 1.5123 0.130 distributed trails permitted the comparison of the dif- Wild boar 1.11 3.70 1.4837 0.138 ference in the frequency of encounters in the two parks. Domestic cattle 6.14 8.33 0.7053 0.480 In the 145-km distance covered in Mundanthurai during Sambar deer 11.66 9 0.7138 0.762 Rat 1.67 7.41 2.4501 0.014 the total sampling period, chital herds were encountered Indian bison 0.56 0 0.7781 0.436 4 times; in the 140-km distance covered in Mudumalai, Munjac deer 2.23 8.33 2.4070 0.016 chital herds were encountered 17 times. These frequencies Pangolin 0 4.63 2.9041 0.003 di€ered signi®cantly (p < 0:01, two-tailed binomial test). Nilgiri langur 0 8.33 * The distribution of scat also indicates that leopards in Bonnet macaque 0 0.92 1.2897 0.1971 Hanuman langur 2.79 0.92 * Mundanthurai were preferentially distributed near Porcupine 0.56 5.55 2.6586 0.007 human settlementsÐthere was a higher density of leo- Unclassi®ed 3.35 3.70 0.1574 0.875 pard scat within a 5-km radius of human settlements Total samples 100 100 (1.26 scats/km compared with 0.69 scats/km beyond 5 a Note that negative Z-values indicate that the proportion of the km). One of the key indices of the leopards' preferential speci®c species was higher in Mundanthurai. use of areas near human habitation was revealed in the * Nilgiri langurs and Hanuman langurs were not compared because survey of local human residents. A total of 58 families scat collection was conducted in areas where the two species were were surveyed to quantify predation on domestic ani- mutually exclusive. mals. Thirty-four families surveyed had lost chickens to leopards at least once. Thirty-one families had lost cat- Felids are extremely dicult to census (Karanth, tle to leopards. Twenty-three families admitted to steal- 1987; Nowell and Jackson, 1996), hence we attempted ing kills from leopards, if the kill was a sambar deer, to compare the relative density of leopards in the two chital deer or wild boar. Such prey-stealing by humans parks using an index of leopard scat density. To achieve has been reported for other areas (Johnsingh, 1983). this, we compared the number of scats collected with the Comparisons of grazing land changes in the two linear distance covered in one month, which included all parks from the 1-km2 resolution satellite data using the trails sampled only once. Therefore, Calibrated Vegetation Index revealed that, in Mun- danthurai, 42.6% of grazing land in a 101 km2 area Relative density ˆ Number of scats=total trail distance measured from 1986 data had shifted to thicket by 1996. In contrast, 199 km2 area of grazing land measured in Mudumalai in 1986 remained essentially unchanged in 1996.

4. Discussion

The lack of tiger scat in Mundanthurai suggests that the park, classi®ed as a tiger reserve because of its once high tiger densities, has very few, if any, tigers left. It is possible to misclassify the scat of young tiger cubs (less than 6 months of age) as leopard scat; albeit, there should be an overlapping distribution of tiger cub scat and adult tiger scat because tiger cubs continue to live with their mothers until 2±3 years of age (Nowak, 1991). Since we did not ®nd any adult tiger scat in Mun- Fig. 3. The occurrence of prey in leopard diet as a function of weight danthurai, it is unlikely that we misclassi®ed tiger cub class is shown for four parks in southern India. Note that prey scat as leopard scat. exceeding 50 kg did not di€er signi®cantly among the parks whereas The ®ndings of this study suggest that leopards in prey between 21 and 50 kg were signi®cantly lower in Mundanthurai than in the other parks (p < 0:01). Conversely, prey less 21 kg were Mundanthurai are feeding on smaller and perhaps less signi®cantly more abundant in Mundanthurai (p < 0:01). preferred prey, probably as a result of low ungulate 118 U. Ramakrishnan et al. / Biological Conservation 89 (1999) 113±120 density. However, a low density of large prey may not in northern India. In Bandipur and Nagarhole, the adversely a€ect the leopard population. Leopards are complexity of the vegetation types and the large prey opportunists and are very ¯exible in their diet, and can base were reported to be the main reasons for the coex- thus survive in a region where the ungulate densities are istence of leopards and tigers in these areas. Similarly, in low. Their ability to feed on both small and large prey, Chitawan National Park, the coexistence of tigers and to climb trees and scavenge (Johnsingh, 1983) may help leopards has been credited to the abundance of prey in them survive in a highly disturbed habitat where prey both the larger and smaller weight classes. are scarce. Tigers, on the other hand, are not good Previous studies have looked at the prey preference of climbers, limiting their ability to hunt arboreal prey, large carnivores as a function of prey size (Karanth and none of which were found in the Mudumalai tiger scats. Sunquist, 1995; Scheel, 1993). These studies compared Unlike tigers, leopards are more likely to move through their observations in light of foraging theory (Stephens open terrain and raid villages for domestic animals, and Krebs, 1987), where the most pro®table prey is that which allows them to survive in fragmented habitats measured by the ratio of energy gain to prey-handling (Seidensticker and Lumpkin, 1996). Although meagre, time. Leopard prey typically range in weight from a few our sample of tiger scat from Mudumalai suggests that 100 g (e.g. rodents) to over 100 kg, with the preferred tigers are focusing on large ungulate prey. The much weight being between 20 and 50 kg. Similar observations heavier tiger, about four times the weight of leopards have been made in Africa (Schaller, 1972) where leo- (Seidensticker, 1976), probably cannot survive on very pards preferentially kill prey in the 20±70 kg weight small prey. In light of our ®ndings, it seems reasonable class. Thus, chital deer would appear to be the most to suggest that increasing large ungulate densities in pro®table preyÐlarge enough to provide a full meal and Mundanthurai would probably attract tigers to the small enough to not cause major harm to the predator. park. Although wild boar fall under the same weight-class Based on other studies in southern India, there is a category as chital deer, they are very aggressive and can large overlap in leopard, wild dog, and tiger diet pre- retaliate viciously, which can cause serious injury to an ferences (Johnsingh, 1983; Karanth and Sunquist, attacking leopard. Similarly, sambar deer are larger and 1995). Evidence suggests that among large sympatric more aggressive than chital deer, and this could be a carnivores, the larger carnivores can prey on broader reason for their lower occurrence in our scat samples. size ranges of prey classes due to their prey handling Complementary ®ndings of tiger diet support this argu- capabilities (Gittleman, 1983). In Chitawan National ment because chital deer are the most frequently eaten Park where tigers and leopards coexist, tigers were prey (Nagarhole park, Karanth and Sunquist, 1995; recorded taking a much wider range of prey sizes than Chitawan park, McDougal, 1977; Kanha park, Schaller, leopards (Seidensticker, 1976). In regions of high tiger 1967). density, for example, tigers are known to out-compete Chital deer have a wide geographic distribution and leopards (McDougal, 1988; Schaller, 1967,1972), the are found throughout the Indian sub-continent. Density capacity of which includes opportunistic stealing of estimates of chital deer have been recorded for three of leopard prey as well as killing leopards (Seidensticker, the four parks mentioned above. Varman and Sukumar 1976). Radio-tracking studies on tiger and leopard (1995) estimated a density of 25 chital/km2 in Mudu- movements indicate that leopards avoid areas fre- malai. Karanth and Sunquist (1995) estimated a density quented by tigers (Seidensticker, 1976), preferring the of 49 chital/km2 in Nagarhole. A similar survey of prey periphery of parks near human settlements. However, in densities conducted in Bandipur revealed an estimated regions of low tiger density, such interspeci®c social density of 44 chital/km2 (Johnsingh, 1983). Although no dominance is not common (Robinowitz, 1989); leopards prey density estimation studies have been conducted in are known to have a more diverse prey base than tigers Mundanthurai, our infrequent observations of chital in the lower weight classes of prey. Results from the herds suggest that their density is much lower than in current study and that of other studies in the region Mudumalai. appear to support these ®ndings (Johnsingh, 1983; The rapid decline in tiger populations world wide has Karanth and Sunquist, 1995; Rice, 1986). Thus, a low been attributed to habitat loss and poaching (Nowell density of prey in the higher weight classes can restrict and Jackson, 1996). Our failure to observe tiger pug the distribution of tigers, but may not a€ect leopard marks and tiger scat during this study seems to indicate distribution. that there are very few tigers on the Mundanthurai Pla- The results of our study of leopard diet in the Mudu- teau. Most of the conservation initiatives for the tiger malai Wildlife Sanctuary is consistent with those from have focused on setting aside reserves to protect impor- the adjacent Bandipur Tiger Reserve (Fig. 1A,C) and tant tiger habitat (Cox, 1998) and that was one of the Nagarhole National Park (Johnsingh, 1983; Karanth major objectives of the Kalakad-Mundanthurai Tiger and Sunquist, 1995). It is also consistent with the ®nd- Reserve. However, it appears that protection of the ings from Chitawan National Park (Seidensticker, 1976) habitat alone is not sucient; some modi®cations to the U. Ramakrishnan et al. / Biological Conservation 89 (1999) 113±120 119 habitat might be essential to restore tigers in this park. Hintze, J.L., 1987. Number Cruncher Statistical System, Version 6.0. Park management decisions for increasing large carni- Kaysville, Utah. vores in the park can be based on prey density estimates Johnsingh, A.J.T., 1983. Large mammalian preyÐpredators in Ban- dipur. J. Bombay Nat. Hist. Soc. 80, 1±57. coupled with the study of leopard diets. Since this is the Karanth, K.U., 1987. Tigers in India: a critical review of ®eld census. ®rst study on carnivore diets in Mundanthurai, we are In: Tilson, R.L., Seal, U.S. (Eds.), Tigers of the World. Noyes unable to record di€erences in diet that resulted from Publications, Park Ridge, New Jersey, pp. 118±132. recent changes in park management. Future research Karanth, K.U., Sunquist, M.E., 1995. Prey selection by tiger, leopard should focus on con®rming our tentative conclusion and dhole in tropical forests. J. Anim. Ecol. 64, 439±450. Kidwell, K.A., 1991. NOAA Polar Orbiter Data Users Guide: that the large ungulate densities are low in the park and TIROS-N, NOAA-6, NOAA-7, NOAA-8, NOAA-9, NOAA-10, determining the causes of this decline. Hunting of large NOAA-11 & NOAA-12. National Oceanic and Atmospheric ungulates by humans is minimal in this park and is thus Administration, National Environmental Satellite, Data, and Infor- not a contributing factor. Vegetation changes, such as mation Service, National Climatic Data Center, Satellite Data Ser- the reduction of available grasses for grazing, might vices Division. McDougal, C., 1977. The Face of the Tiger. Rivington Books, explain this decline in large ungulates. The optimum London. habitat for ungulates, especially chital, has been shown McDougal, C., 1988. Leopard and Tiger Interactions at Royal Chit- to consist of grasses interspersed with shrubs and trees wan National Park, Nepal. J. Bombay Nat. Hist. Soc. 85, 609±610. (Eisenberg and Seidensticker, 1976). Comparisons of Norton, P.M., Lawson, A.B., Henley, S.R., Avery, G., 1986. Prey of current vegetation cover, both grasslands and forest leopards in four mountainous areas in south-western Cape Pro- vince. S. African. J. Wildlife Res. 16, 47±52. understory, with that of earlier surveys will shed light Nowak, R.M., 1991. Walker's Mammals of the World, 5thJohns on the relationship between habitat change and its Hopkins University Press, Baltimore and London. e€ects on large ungulates essential for tiger survival. Nowell, K., Jackson, P., 1996. Wild Cats, Status Survey and Conservation Action Plan. IUCN Publication Services Unit, Cambridge. Panwar, H.S., 1987. Project tiger: the reserves, the tigers and their future. In: Tilson, R.L., Seal, U.S. (Eds.), Tigers of the World. Acknowledgements Noyes Publications, Park Ridge, New Jersey, pp. 110±117. Pelkey, N.W., 1997. A Refuge for Aranya: A Bioeconomic Compar- We thank the Forest Department of Tamil Nadu for ison of Four Habitat Management Regimes in Southern India. Ph.D. Dissertation, University of California, Davis. permission to conduct research in the Kalakad-Mun- Rabinowitz, A.R., 1989. 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