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“Among carnivores cats stand supreme in equipment of tooth and claw, and supreme again in that combination of grace, strength and agility which is the mark of the tribe.”
- S.H Prater
With the ability to thrive not just in forests like the tiger or open savanna, like the lion, the leopard or panther is the most successful big cat in terms of colonizing new and varied terrain. That these felids can subsist on a host of small prey species as well as their traditional medium-sized ungulate prey increases their impressive ability to live in all manner of habitat. This is perhaps why these adaptable carnivores have spread virtually throughout Asia and roam over all of Africa except for the Sahara (S.H Prater, 1965). Despite this renowned adaptability, the leopard is fast disappearing, relegated to smaller and smaller pockets across its range. A thriving world market for its skins during the late 1960s combined with steady and continuing habitat loss caused the United States to list the leopard as an endangered species throughout its range in March 1972. Three years later the leopard was added to Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), which completely restricted any trade in leopard products (Baily, 1992). While the southern African species has since been down-listed to threatened, the Asian species remain on the endangered list.
The Sri Lankan leopard (Panthera pardus kotiya)
The origin of the leopard on the subcontinent of India is unknown but it is believed that it migrated down from the North/West passes and from here spread out across the realm (S.H. Prater, 1965). Initially, it was believed that this is the only leopard population to have evolved as the top predatory carnivore in its ecosystem, having been isolated from intra-guild competition since Sri Lanka split off from the Indian sub-continent (Guggisberg 1975; Miththapala et al. 1996; Turner 1997). The sea level rise that separated Sri Lanka was ~5,000-10,000 ybp (Deraniyagala 1992; Anderson 1998; Yokoyama et al. 2000). Deraniyagala (1939) reported a lower carnassial in an alluvial deposit in the southwestern wet zone from which he erected a new sub-species of lion (Panthera leo sinhaleyus Deraniyagala 1938). The frequent reference to the lion in Sri Lankan history, art, legend and folklore were seen to further support their likely existence (Deriniyagala 1958). However the Sinhalese (“people of the lion”) are believed to have come to Sri Lanka from north-western India, where the last outpost of the Asian lion (Panthera leo) remains today and it is these cultural links that appear to better explain the importance of the lion as a symbolic theme (deSilva 1981; Manamendra-Arachchi 2005). The support for it being a separate sub-species is debatable but nonetheless, it appears to have become extinct on the island before the arrival of culturally modern humans ca. 37,000 YBP (Manamendra-Arachchi 2005). More recent fossil discoveries indicate that at one time tigers (Panthera tigris) also inhabited the island, having arrived prior to the latest glacial maximum ca. 20,000 YBP (Manamendra-Arachchi 2005). The tiger fossil evidence, a right middle phalanx, was C14 dated to ~16, 500 YBP (Manamendra-Arachchi 2005).
That the leopard is now the only large mammalian predator in Sri Lanka makes this a unique location in which to conduct a study. This extended lack of large felid competition, unknown elsewhere, is perhaps the reason behind the Sri Lankan leopard’s purportedly more diurnal and less arboreal habits than its continental brethren (Muckenhirn and Eisenberg, 1973). Being the sole large predatory carnivore in the Sri Lankan ecosystem also drastically increases its role as a potential keystone species, helping to determine the densities and numbers of prey species such as spotted/axis deer (Axis axis), barking deer (Muntiacus muntjak), wild boar (Sus scrofa) and sambhur (Cervus unicolor).
In Sri Lanka, the current population of leopards roaming the island is estimated at 750-1000 adult individuals (Kittle & Watson 2008; IUCN 2016). The numbers of these elusive animals have decreased substantially over the last century. This was originally due to game hunting during colonial times and later through poaching for skins. The passage of the Fauna and Flora Protection Ordinance of 1938 put leopards under legal protection, however poaching both inside and outside protected areas continued unabated (Muckenhirn and Eisenberg, 1973). Even today poaching outside and within the country’s national parks is far from a thing of the past. From January 2001 to the present there have been at least 35 leopards killed by poachers in Sri Lanka.
However the major causes for population decline- habitat loss and fragmentation - are less direct and if anything, more difficult to mitigate. With a burgeoning human population already surpassing 19 million and the territorial constraints inherent in island ecosystems, the destruction of leopard habitat for human use is more evident than ever. That there is a concerted effort in the country to become self-sufficient, especially in the production of rice, compounds the problem of human/leopard interactions as more and more land area is converted into paddy for agricultural utilization. Maintaining a balance between the needs of the people of Sri Lanka and the requirements of the island’s wildlife is a fundamental goal for the WWCT.
The Future
Devising a balanced conservation strategy for the Sri Lankan leopard is becoming more and more important and it is hoped that by gaining insight into the demography, range use and behavior patterns of the leopards this study can provide an initial, solid groundwork from which informed and progressive decisions can be made. For the habitat of the leopard is fast disappearing and if this remarkable species is to be preserved in the remaining habitable pockets an increased understanding of them is essential.
In Sri Lanka, it is the elephant (Elephus maximus) that has been used as the flagship species for conservation (P. Fernando 1993,1997, 1998; Jayawardene 1994; Santiapillai and Jackson 1990). The leopard, other than for a few indirect studies in the past (Eisenberg & Lockhart, 1971; Santiapillai et al, 1982, de Silva & Jayaratne, 1994), was largely ignored and its conservation not adequately addressed until recently. The last decade has seen a change, with the leopard taking a more prominent place in Sri Lanka and the work of WWCT's Leopard Project addressing the earlier lack of scientific data and specific conservation practices. The importance of this ongoing full-scale leopard research project is therefore critical for the preservation of this vital predator species.
Project Impetus: The conservation of the Sri Lankan leopard in its natural habitat.
The main thrust behind our research is the future conservation of the Sri Lankan leopard (Panthera pardus kotiya) in its natural habitat. It has long been accepted that no comprehensive and cohesive species conservation strategy can be mapped out, let alone implemented without a thorough grounding in the life history of the species in question. By studying the fundamental aspects of leopard ecology – including range use, diet and sociability - and behavior we are attempting to fill the void that existed in this regard in Sri Lanka.
In addition, working closely with leopards in the country has acted to increase our awareness of the myriad problems facing this important species. Such threats as habitat depletion and encroachment are a common phenomenon for thousands of species across the globe and they exert a similarly severe pressure in Sri Lanka. While our experiences in our Yala site have been insightful in this regard, it is our current and future work in other, unprotected parts of the country that will provide a more rounded understanding of the degree to which these human-expansion-induced problems exist. We plan to document as much as possible the extent of actual and potential leopard habitat in the study areas, the connectivity between forest patches and leopard populations (see Forest Connections) as well as the amount of human disturbance within these patches. This is necessary for future management planning, taking into account the spatial attributes determining leopard home range organization.
Another threat that often works hand in hand with the increased leopard-human interactions resulting from habitat loss, is poaching. Together with various interested parties in Sri Lanka, we are attempting to both document poaching within the country as well as attempt to understand the source of demand for leopard products locally, regionally and internationally. See Anti Poaching Initiatives.
The role that the Sri Lankan leopard plays, not only as the main predator but also the only substantial predator in the ecosystem, needs badly to be determined for it has the potential to be of immense importance. The leopard may truly be a keystone species whose existence is essential to the present environmental balance. Removing this top cat from the arid zone environment, for example, might drastically change the population structure of its present prey species. It could also cause dramatic consequences for a host of species lower on the food chain that appear to depend at least to some degree on leopard hunting success. Furthermore, with prey populations unconstrained, overgrazing has the real potential to alter the very morphology of the ecosystem.
As overgrazing tends to make barren fertile lands; this, in turn, can influence and change the quality and type of land usable not only for the wildlife within these habitats but also for the humans living within and around these areas.
Whether the leopard really is a keystone species in Sri Lanka and the types of cascading effects that its presence exerts on the lower trophic levels are questions that the WWCT is interested in addressing.