James L.D. Smith

Bringing the Tiger Back from the Brink—The Six Percent Solution

The Tiger Summit, to be hosted by Prime Minister Vladimir Putin in Russia in November 2010—the Chinese Year of the Tiger and the International Year of Biodiversity—promises to be the most significant meeting ever held to discuss the fate of a single non-human species. The Summit will culminate efforts by the Global Tiger Initiative (GTI), launched in 2008 by Robert Zoellick, World Bank President. Leaders of 13 tiger range states, supported by international donors and conservationists attending the summit, are being asked to commit to substantive measures to prevent the unthinkable: extinction of the worlds last wild tiger populations. Wild tiger numbers are at an historic low. There is no evidence of breeding populations of tigers in Cambodia, China, Vietnam, and DPR Korea. Current approaches to tiger conservation are not slowing the decline in tiger numbers [1]–[3], which has continued unabated over the last two decades. While the scale of the challenge is enormous, we submit that the complexity of effective implementation is not: commitments should shift to focus on protecting tigers at spatially well-defined priority sites, supported by proven best practices of law enforcement, wildlife management, and scientific monitoring. Conflict with local people needs to be mitigated. We argue that such a shift in emphasis would reverse the decline of wild tigers and do so in a rapid and cost-efficient manner.

THE ROLE OF DISPERSAL IN STRUCTURING THE CHITWAN TIGER POPULATION

Dispersal in tigers was studied in Royal Chitwan National Park, Nepal. Thirty six adult and young were studied to monitor movements and social interactions relative to dispersal. Fourteen subadults were followed from before their dispersal until they died or established post-dispersal territories. Subadult tigers became semi-independent of their mother when her next litter was born. They usually remained within her natal area until the subsequent litter began to move with her at about 2 mos of age. Animals dispersed between 19 and 28 mos. Males dispersed farther than females and settled in poorer habitat. Three of 4 females settled adjacent to their mothers; in two cases the mother shifted her territory allowing the daughter to take over a large portion of the mothers former territory. Wounds on young prior to dispersal indicated that aggression prompted dispersal. Fjghts were observed between dispersers and residents. After fights, dispersers always left the residents area. All 4 dispersing females established breeding territories. Females settled next to their mothers tending to reduce the genetic variance of a males offspring. Eight of 10 males became localized in temporary, post-dispersal territories; 4 of the 8 survived. Two males died of poisoning and 2 from intrasexual aggression. Surviving males either expanded temporary territories or shifted to new areas to establish breeding territories. The Chitwan tigers are an isolated remnant of a population once continuous across the lowlands of Nepal. Effective population size was estimated to be <30 animals. Tigers did not disperse across cultivated areas but did travel through degraded forest habitat. No animal dispersed outside the Chitwan region and there appear to be effective barriers separating Chitwan from the two nearest populations 150 and 250 kms distant. The Chitwan population is probably one of the largest tiger populations remaining in the world. Isolation and small size threaten these populations with stochastic events that may lead to further reduction in population size.

Science deficiency in conservation practice: the monitoring of tiger populations in India

Conservation practices are supposed to get refined by advancing scientific knowledge. We study this phenomenon in the context of monitoring tiger populations in India, by evaluating the ‘pugmark census method’ employed by wildlife managers for three decades. We use an analytical framework of modern animal population sampling to test the efficacy of the pugmark censuses using scientific data on tigers and our field observations. We identify three critical goals for monitoring tiger populations, in order of increasing sophistication: (1) distribution mapping, (2) tracking relative abundance, (3) estimation of absolute abundance. We demonstrate that the present census-based paradigm does not work because it ignores the first two simpler goals, and targets, but fails to achieve, the most difficult third goal. We point out the utility and ready availability of alternative monitoring paradigms that deal with the central problems of spatial sampling and observability. We propose an alternative sampling-based approach that can be tailored to meet practical needs of tiger monitoring at different levels of refinement.

Influence of food distribution and predation pressure on spacing behavior in palm civets

The common palm civet, Paradoxurus hermaphroditus , was studied in Royal Chitwan National Park, Nepal, to determine daily and seasonal movements in relation to availability of food and predation pressure. Five adult animals (two females and three males) were captured and fitted with radiocollars and located every other day. Each animal was followed for 12 consecutive h/month. Palm civets were strictly nocturnal; activity began at ca. 1800 h and ended at ca. 0400 h. Animals were more active on dark nights than on bright, moonlit nights and typically rested during the day in the crown of vine-covered trees. Seeds of fruits were found in 84.5% of 193 scats of palm civets that were collected December 1989 to June 1990. In April, when ripe fruits were not readily available, a shift in diet from fruits to vertebrate and invertebrate prey occurred. Palm civets also fed on the nectar of Bombax ceiba and sap from stems of Vallaris solanacea . Home-range sizes varied inversely with the amount of food available. A high degree of home-range overlap indicated that individuals were not territorial. Documented predation and exclusive nocturnal activity suggest that palm civets are vulnerable to predation by large carnivores in the park. Strong predation pressure and high temporal and spatial variation in availability of food resources may account for the apparent absence of territorial behavior of palm civets in this population.

TIGMOD: an individual-based spatially explicit model for simulating tiger/human interaction in multiple use forests

Abstract The loss of tiger habitat and the greater dependency of tiger populations on multiple use forests has led to an increase in conflict between tiger and human forest use. Gaining a better understanding of this conflict through a combination of fieldwork and modeling is critical to the survival of tiger populations in these forests. TIGMOD is an individual-based spatially explicit, object-oriented model that simulates key aspects of tiger behavior and its interactions with wild and domestic prey through stochastic processes. It is a dynamic model driven by changes in states of tigers or prey that trigger the behavior and interactions appropriate to these changes. The model permits users to run the simulation based on different scenarios that explore the relationship between prey densities and tiger survivability, as well as those that examine the relationship between villager attitudes towards tiger killing of domestic prey and the likelihood of poisoning a tiger. Model output includes number of tigers born, starved, or poisoned, and number of wild and domestic prey killed. Model simulation results agree well with field observations and data in terms of prey density versus tiger survivability, number of days between two consecutive prey kills, simulated movement of tiger traversal of its home range, and number of cubs born per breeding female tiger. This study shows that tiger populations are sustainable at low density of domestic prey but not sustainable if domestic prey density increases to three or more per square kilometer. Additionally, change in behavior and attitudes of villagers towards tigers, such as increasing guarding of livestock and higher tolerance of domestic prey kills will significantly reduce tiger mortality caused by poisoning. TIGMOD is a useful tool for analyzing the interaction between tigers and humans in multiple use forests. It provides a means of understanding the right balance between forest use by tigers and use by villagers, which can lead to implementation of management strategies that optimize both.

Seasonal and Habitat-Related Diets of Sloth Bears in Nepal

Most bears are opportunistic omnivores; their diets consist of fruits, other vegetative material, and in lesser amounts, mammals, fishes, and insects. Sloth bears ( Melursus ursinas ) are the only species of ursid specifically adapted to feed on insects, especially termites and ants, although they also feed on fruits when available. We studied diets of sloth bears in Royal Chitwan National Park, Nepal, where fruits are available for ca. 4 months (May–August) and access to colonies of termites is reduced in lowlands that are flooded during the fruiting season. We analyzed feces and observed sloth bears foraging to investigate their responses to changes in availability of food. Diets of sloth bears were dominated by insects (>90%), especially termites (≥50%), from September through April, but they relied heavily on fruits from May through August. Seasonal movements between lowland and upland habitats seemed to be prompted mainly by availability of termites. Termites were more dominant in the diets of sloth bears in our study than in a study conducted 20 years ago in Royal Chitwan National Park and in studies in India. The dietary shift of sloth bears in Royal Chitwan National Park may have been related to changes in habitat conditions associated with relocation of people out of the Park. It appears that sloth bears, like other bears but unlike other myrmecophagous mammals, can adapt their diet to changing food conditions.

Subspecies Genetic Assignments of Worldwide Captive Tigers Increase Conservation Value of Captive Populations

Tigers (Panthera tigris) are disappearing rapidly from the wild, from over 100,000 in the 1900s to as few as 3000. Javan (P.t. sondaica), Bali (P.t. balica), and Caspian (P.t. virgata) subspecies are extinct, whereas the South China tiger (P.t. amoyensis) persists only in zoos. By contrast, captive tigers are flourishing, with 15,000-20,000 individuals worldwide, outnumbering their wild relatives five to seven times. We assessed subspecies genetic ancestry of 105 captive tigers from 14 countries and regions by using Bayesian analysis and diagnostic genetic markers defined by a prior analysis of 134 voucher tigers of significant genetic distinctiveness. We assigned 49 tigers to one of five subspecies (Bengal P.t. tigris, Sumatran P.t. sumatrae, Indochinese P.t. corbetti, Amur P.t. altaica, and Malayan P.t. jacksoni tigers) and determined 52 had admixed subspecies origins. The tested captive tigers retain appreciable genomic diversity unobserved in their wild counterparts, perhaps a consequence of large population size, century-long introduction of new founders, and managed-breeding strategies to retain genetic variability. Assessment of verified subspecies ancestry offers a powerful tool that, if applied to tigers of uncertain background, may considerably increase the number of purebred tigers suitable for conservation management.

How much gene flow is needed to avoid inbreeding depression in wild tiger populations

The number and size of tiger populations continue to decline owing to habitat loss, habitat fragmentation and poaching of tigers and their prey. As a result, tiger populations have become small and highly structured. Current populations have been isolated since the early 1970s or for approximately seven generations. The objective of this study is to explore how inbreeding may be affecting the persistence of remaining tiger populations and how dispersal, either natural or artificial, may reduce the potentially detrimental effect of inbreeding depression. We developed a tiger simulation model and used published levels of genetic load in mammals to simulate inbreeding depression. Following a 50 year period of population isolation, we introduced one to four dispersing male tigers per generation to explore how gene flow from nearby populations may reduce the negative impact of inbreeding depression. For the smallest populations, even four dispersing male tigers per generation did not increase population viability, and the likelihood of extinction is more than 90% within 30 years. Unless habitat connectivity is restored or animals are artificially introduced in the next 70 years, medium size wild populations are also likely to go extinct, with only four to five of the largest wild tiger populations likely to remain extant in this same period without intervention. To reduce the risk of local extinction, habitat connectivity must be pursued concurrently with efforts to increase population size (e.g. enhance habitat quality, increase habitat availability). It is critical that infrastructure development, dam construction and other similar projects are planned appropriately so that they do not erode the extent or quality of habitat for these populations so that they can truly serve as future source populations.

Use of an action-selection framework for human-carnivore conflict in the Bangladesh sundarbans.

Human-carnivore conflict is manifested in the death of humans, livestock, and carnivores. The resulting negative local attitudes and retribution killings imperil the future of many endangered carnivores. We tailored existing management tools to create a framework to facilitate the selection of actions to alleviate human-carnivore conflict and applied the framework to the human-tiger conflict in the Bangladesh Sundarbans. We identified potential actions that consider previous management efforts, local knowledge, cost-effectiveness, fieldwork experience of authors and project staff, previous research on tiger ecology by the authors, and recommendations from human-carnivore conflict studies in other countries. Our framework includes creation of a profile to improve understanding of the nature of the conflict and its underlying causality. Identified actions include deterrents, education, direct tiger management, and response teams. We ranked actions by their potential to reduce conflict and the monetary cost of their implementation. We ranked tiger-response teams and monitoring problem tigers as the two best actions because both had relatively high impact and cost-effectiveness. We believe this framework could be used under a wide range of human-wildlife conflict situations because it provides a structured approach to selection of mitigating actions.

Sympatric Asian Felid Phylogeography Reveals A Major Indochinese-Sundaic Divergence

The dynamic geological and climatological history of Southeast Asia has spawned a complex array of ecosystems and 12 of the 37 known cat species, making it the most felid‐rich region in the world. To examine the evolutionary histories of these poorly studied fauna, we compared phylogeography of six species (leopard cat Prionailurus bengalensis, fishing cat P. viverrinus, Asiatic golden cat Pardofelis temminckii, marbled cat P. marmorata, tiger Panthera tigris and leopard P. pardus) by sequencing over 5 kb of DNA each from 445 specimens at multiple loci of mtDNA, Y and X chromosomes. All species except the leopard displayed significant phylogenetic partitions between Indochina and Sundaland, with the central Thai–Malay Peninsula serving as the biogeographic boundary. Concordant mtDNA and nuclear DNA genealogies revealed deep Indochinese–Sundaic divergences around 2 MYA in both P. bengalensis and P. marmorata comparable to previously described interspecific distances within Felidae. The divergence coincided with serial sea level rises during the late Pliocene and early Pleistocene, and was probably reinforced by repeated isolation events associated with environmental changes throughout the Pleistocene. Indochinese–Sundaic differentiations within P. tigris and P. temminckii were more recent at 72–108 and 250–1570 kya, respectively. Overall, these results illuminate unexpected, deep vicariance events in Southeast Asian felids and provide compelling evidence of species‐level distinction between the Indochinese and Sundaic populations in the leopard cat and marbled cat. Broader sampling and further molecular and morphometric analyses of these species will be instrumental in defining conservation units and effectively preserving Southeast Asian biodiversity.