Abstract The Nilgiri tahr Nilgiritragus hylocrius is an Endangered species of mountain ungulate endemic to the Western Ghats of India, a biodiversity hotspot. Habitat fragmentation, hunting and a restricted range are the major threats to this species. Although several surveys have assessed the species’ status, a population estimate based on a scientifically robust method is needed. We used the double-observer method to estimate the population of the Nilgiri tahr in the Anamalai Tiger Reserve, a protected area in the Western Ghats. We walked 257 km of transects across the Reserve, covering 36 grassland blocks (i.e. clusters of montane grasslands that were relatively separate from each other). We counted a minimum of 422 individuals in 28 groups, and estimated the tahr population in the study area to be 510 individuals (95% CI 300–858) in 35 groups. The male:female ratio was 0.71 and the young:female ratio was 0.56. Comparing our estimate with previous surveys suggests that the Nilgiri tahr population in Anamalai Tiger Reserve is stable. We found the double-observer survey method to be appropriate for population estimation and long-term monitoring of this species, and make recommendations for improved field protocols to facilitate the implementation of the method in the tropical mountains of the Western Ghats. Our findings suggest that the Reserve harbours 20–25% of the global population of the Nilgiri tahr, highlighting the area's importance for the conservation of this species.
With the uncontrolled expansion of anthropogenic modifications of the environment, wildlife species are forced to interact with humans, often leading to conflict situations that have detrimental effects for both wildlife and humans. Such interactions are escalating globally, making it crucial for us to devise strategies for both, the management of conflict and the conservation of these often-threatened species. We studied a case of potentially detrimental human-wildlife interactions between an endemic, habitat-specialist primate, the lion-tailed macaque Macaca silenus and resident human communities that has developed in recent years in the Western Ghats mountains of southern India. Primates provide useful model systems to understand the extent and nature of behavioural changes exhibited by wildlife in response to anthropogenic habitats with varying degrees of human influence. We documented behaviours, including foraging and intra-species social interactions, to examine the decisions made by the macaques as they exploited four human-modified habitats, which, for the purpose of this study, have been qualitatively characterised to include structural features of the habitat, type of food resources available and the presence of humans. Access to human-origin food, either cooked or packaged, acquired directly from homes or garbage pits, in the human-dominated habitat appeared to significantly reduce active foraging and searching for food, allowing them to engage in other behavioural activities, such as resting. Furthermore, patterns of reciprocated affiliation dissipated in certain human-dominated habitats, with individuals seeming to have adopted novel behavioural strategies, leading to altered social dynamics in the troop, possibly in response to provisioning. This study thus highlights the importance of understanding behavioural changes displayed by animals in response to human interactions; such knowledge could be crucial for the planning and implementation of management and conservation strategies for endangered species such as the lion-tailed macaque and possibly other wildlife in the increasingly anthropogenic landscapes of the tropical world.
Wildlife-vehicle collisions on the roads lead to mortality of a range of animal taxa both within and around wildlife reserves. Quantifying and understanding impacts of roads on wildlife mortality are essential for identifying vulnerable taxa and suitable mitigation measures. We studied animal mortality on roads in relation to habitat and season in the Anamalai Tiger Reserve and adjoining Valparai plateau in the Western Ghats, India. Habitats were broadly classified as forest, monoculture plantations (tea, coffee, eucalyptus) and mixed. Eleven road transects of 3-12 km length were surveyed between 9 and 12 times each during monsoon (2011) and summer (2012). We recorded 2969 roadkills (mean = 2.01/km) during the 1473.4 km of road surveys carried out. The overall roadkill rate was 21.2 (+/- 3.87 SE) individual kills/10 km. Amphibians were most frequent in roadkills (overall roadkill rate of 9.3 +/- 2.17 SE kills/10 km, n = 1307), followed by invertebrates and unidentified taxa (7.6 +/- 1.81 SE kills/10 km, n = 1066). Roadkill rate was 2.4 times higher in monsoon than summer, with amphibians particularly averaging higher kill rate during monsoon. Frequency of roadkills of various animal groups differed between seasons in different habitats. In both the seasons, most roadkills were recorded mainly in tea, forest, and forest-tea habitats. Relative to length of roads through forest, a disproportionately large number of roadkills of herpetofauna and mammals were recorded in forest habitat. Higher vehicular movements, including tourist traffic, road widening, removal of native plants along roads and construction of sidewalls without breaks obstruct animal movements and may be responsible for roadkills. Designing roads to be more permeable for safe animal movement, particularly where roads pass through forest, and sensitizing highways authorities are essential to reduce animal mortality and make roads more wildlife-friendly in this region.
Our society faces some serious challenges and we are primed to think that there are always some administrative solutions to them. A careful analysis shows that socially relevant science can tackle such challenges. We discuss one such issue involving science, society, culture and administration – the challenge of dealing with human– wildlife conflict.
To determine abundance, density and distribution of wild animals, it is crucial to estimate populations using reliable sampling techniques. In most earlier studies, elephant populations were estimated employing block counts or dung counts, which provide biased estimates due to limitations of the methods. We estimated an Asian elephant population using distance sampling, a quantitatively robust technique, in Biligiri Rangaswamy Temple Tiger Reserve, a critical elephant conservation area in the Nilgiri Biosphere Reserve in south India. We laid 33 transects with a total length of 93 km. We walked these transects five to 11 times amounting to a total of 795.5 km of walks. We collected data on location, number and age-sex classes through direct elephant sightings, using rangefinders, global positioning systems and compass. We used DISTANCE software for analysis. We estimated per km2 cluster density as 0.69 elephant herds, mean cluster size as 2.44, and elephant density as 1.7 animals. This amounts to a total of 713 elephants in 610 km2 of the sanctuary. A high percentage of males less than 30 years old and a low immature:adult female ratio indicated the severity of poaching in the recent past in the study region.
The persistence of wide-ranging mammals such as Asian elephants in fragmented landscapes requires extending conservation efforts into human-dominated landscapes around protected areas. Understanding how elephants use such landscapes may help facilitate their movements and reduce conflict incidence. We studied elephants' use of fragmented habitats and ranging patterns of focal herds in a landscape of rainforest fragments embedded in tea, coffee, and Eucalyptus plantations in the Anamalai Hills. Elephant herds entering this landscape were tracked daily between April 2002 and March 2006, resulting in 985 GPS locations of herds obtained across six major habitats. Natural vegetation in rainforest fragments and riparian habitats, despite low coverage in the landscape, was preferred by elephants during the day. At night, elephants preferred riparian vegetation, avoided other habitats such as swamps and settlements, while the remaining habitats were used proportional to availability. Use of rainforest fragments and riparian vegetation increased over three years of study with a corresponding decline in the use of tea monoculture. Among plantation habitats, coffee, and Eucalyptus were used significantly more during wet and dry seasons, respectively. The concentration of elephants along a major riparian system in the center of the landscape emphasized the role of water and food availability in habitat use during the dry season. Protection of rainforest fragments, secondary vegetation along rivers, and regulated and sequential felling (instead of clear-felling) of Eucalyptus along elephant movement routes will help retain forage, cover, and passage routes of elephant herds and may reduce direct human-elephant encounters in such fragmented landscapes.
During a 5-yr study of lion-tailed macaques in their natural habitat, we found that: 1) most births occurred from January to April (70%) and from September to December (19%), showing a bimodal pattern with a major and a minor birth peak; 2) the period of peaks remained the same over 5 yr; and 3) a similar pattern of birth peaks occurred both in groups in large forest complexes that had overlapping home ranges with other groups and in single groups that were isolated in forest fragments in the same region but with similar ecological conditions. The results suggest more of a birth seasonality than mere breeding synchronization in the wild lion-tailed macaques. We also analyzed data on births in captivity in European Zoos for 10 yr. We observed no seasonality or peaks in births, and the pattern was the same over the years. Data on rainfall suggest that resource availability in the wild habitat may not be uniform throughout the year; hence, ecological factors may play an important role in determination of birth patterns in the natural habitats of lion-tailed macaques.
In bonnet macaques, males usually disperse between groups and females remain philopatric, but researchers have reported female transfer. We report a rare case of male influx during the mating season in our bonnet macaque study group in the Anaimalai Hills. The density of bonnet macaques in the study region was unusually high. The study group had a single, crippled adult male with a long tenure and 5 adult females. During the mating season, adult females approached and mated with outgroup males, and then several males entered the group. The adult male left the group without any resistance. The incoming males mated with 3 receptive females, forcibly mated with 2 lactating females, and attacked and killed 2 infants. During the influx, 2 outgroup females joined the group. The data suggest that male influxes provide an opportunity for infanticide and female transfer, which can have important fitness consequences even in species in which they rarely occur.
In many places in the Western Ghats hill ranges of southern India, rainforest has been clear-felled in order to grow tea plantations. Such plantations now exist as islands of agriculture surrounded by forest tracts, most of which are protected as wildlife sanctuaries. We report a case study from one such tea garden. We observed a diversity of wild mammals, both herbivores and carnivores, using open grass patches, swamps and vegetation along streams in the tea garden. Large mammals were observed to forage in such areas and return to the adjoining forests. Small mammals were either resident or used stream vegetation as a corridor to move from one side of the forest to the opposite side. Dhole (Cuon alpinus) often preyed on sambar (Cervus unicolor) and even denned twice in the estate. We also observed a minimal human-animal conflict in the area. Problems such as stealing of meat from sambar kills made by dhole, could be overcome by awareness. We propose that such areas can be effectively managed such that it could facilitate movement of wild mammals with least damage to the commercial activity related to tea. Such a wildlife management strategy can become a model that could be followed in tea-growing areas throughout the Western Ghats.
The lion‐tailed macaque is an endangered species, and hence it is necessary that the remaining populations in the rainforests of the Western Ghats, India, be located and their habitats assessed for effective conservation. The Anaimalai Hills in the state of Tamil Nadu harbor 31 groups of lion‐tailed macaques. However, the rainforest in these hills is highly fragmented. Since lion‐tailed macaques are typically arboreal, the groups have become isolated. Two large rain‐forest complexes in these hills harbor 12 and seven groups, respectively, and the remaining 12 groups inhabit small, isolated forest fragments. Group size ranges from six to 53 individuals, with a mean size of 16.3. In the small forest fragments, the standard deviation (SD) of group size was considerably higher than it was in the larger forest complexes. The disturbed fragments also had a higher variability in group size than the relatively undisturbed habitats. It is believed that fragmentation may impede male migration. We suggest that the fragments be managed in such a way that male migration among groups can be facilitated to overcome the potential effects of isolation. © 2002 Wiley‐Liss, Inc.
This study reports critical changes in the behaviour patterns of lion-tailed macaques (Macaca silenus) inhabiting a continuously changing and deteriorating rain forest fragment in the Western Ghats, India. The study area, a privately owned rain forest patch in a tea/coffee garden called Puthuthotam, has suffered two massive selective logging episodes. Over the years, the native rain forest trees have been largely replaced by non-native/pioneer species resulting in loss of canopy contiguity and significant changes in other vegetation parameters. The almost wholly arboreal lion-tailed macaque now spends a considerable amount of time on the ground in this area. The species has also experienced a major shift in its diet, ranging patterns and other activities.
The paper reports the information on the faunal component in the diet of wild lion-tailed macaques. The faunal component accounts for about 19 per cent of the total diet. There is more intake of faunal items during the dry months from December to May when fruit availability is low, as compared to the wet months from June to November. The faunal intake at different times of the day and by different age-sex classes does not differ. Invertebrates constitute the largest portion of the faunal diet. The smaller animals are captured and eaten by all age-sex classes, whereas the larger vertebrates are usually caught and eaten by adult animals, especially males. The method of capturing the prey and the parts of the body eaten are reported.
AbstractA survey of the slender loris Loris tardigradus, a Vulnerable primate, was carried out in the Dindigul Forests of Tamil Nadu, India, in 1996 in order to assess prevalence. Lorises were found in high densities in the open Euphorbia scrub forests and in crop lands nearby. Although most often seen in bushes and Acacia trees, the species uses a wide variety of vegetation and substrates. Individuals were found mostly at an altitude of 300–500 m. Body measurements taken on sample animals revealed that the population belongs to the subspecies L. t. lydekkerianus. Conservation measures for the species in this region include additional surveys and evaluation of prospects for establishing a slender loris sanctuary.