Journal of the Bombay Natural History Society, 105 (2), May-Aug 2008 (139-147) EVALUATING THE STATUS OF FORESTS AND RELATIVE ABUNDANCE OF WILDLIFE: A RAPID SURVEY FROM A REMOTE AND LITTLE EXPLORED TROPICAL EVERGREEN FOREST OF NORTH-EAST INDIA
AMBIKA AIYADURAI AND SURENDRA VARMA
This survey was aimed at evaluating methods that could be used to assess the status of forests and the relative abundance of mammals in a remote and little explored tropical evergreen forest of north-east India. The survey was carried out by walking along forest trails for assessing the status of forests and mammals, and through the village surveys to assess the status of wildlife. About 58% of the forests surveyed were under open forest and 27% under partially open cover, indicating the region has more open forest while the closed forest was only 15%. The species encounter rate/km was high in an open forest (1.6 (SE=0.22)/km, 0.8 (SE=0.7)/km for a partially open forest and for a closed forest it was 0/km), and the results for the open and partially open forests were not statistically significantly different (Hc=0.39, p=0.73). Out of the 23 mammal species reported for the region, only 26% of the 23 species were encountered during the trail surveys, and only after spending 95% of the total time (56 hours) with the villagers, information on all the species was obtained. The number of species obtained for the survey region complies with the results of other regions that have comparable attributes. When areas with similar affinities are compared, the variance around the mean was only 7%, but in areas that are dissimilar, the variance around the mean was 13%. As compared with the other regions, only 0.37% of the total man-hours were spent to obtain the number of species for the current survey. The village survey appears to be a robust method for a basic or advanced species list, but it may not be an appropriate method to evaluate the forest status. Key words: trail and village surveys, evaluation, forest canopy and wildlife abundance
INTRODUCTION Arunachal Pradesh, in the north-east of India, is known for its rich biological and cultural diversity, and has been recognised as one of the 34 biodiversity hotspots of the world (Myers et al. 2000). It is also a home to around 26 ethnic human communities with distinctive cultures and rich traditions (Shukla 1965). Unlike the other regions, forests in some areas of Arunachal Pradesh at present do not suffer much from major developmental activities, such as the hydroelectric, irrigation projects and road networks. But the heavy dependency on forests by local communities through shifting cultivation and other livelihood practices is the major conservation concern (Ramakrishnan 1992; Raman et al. 1998). The communities are also known for their active involvement in hunting of wildlife for ornamental, medicinal, edible and commercial uses (Aiyadurai and Varma 2003).
There are only a few studies that have been carried out in this region due to the remoteness, ruggedness and incidences of cerebral malaria in the region. High rainfall, frequent landslides, lack of infrastructure facilities and an assumed unfriendly nature of the local communities have also contributed to this. These areas are important for many species of conservation interest and the proposed survey region was particularly reported to have seven species of major large carnivores (Aiyadurai and Varma 2003), three of which (Tiger, Clouded Leopard and Asiatic Black Bear) are categorised in the Vulnerable to Endangered category of the IUCN Red List of threatened species (IUCN 2007), and the remaining four are listed under the Schedule I of the Wildlife (Protection) Act of India 1972 (Menon 2003). The area is also one of the contiguous habitats for the Asian Elephant Elephas maximus; conserving these flagship species (Sukumar 1989) or charismatic flagship species (Karanth 1995) or their habitat may eventually protect a considerable amount of biodiversity. However, the Elephant and some carnivore species have become a cause for human-animal conflict, resulting in negative conservation interests. Such problem animals, particularly some carnivore species are being hunted either as a conflict mitigation measure or as a source of food. Under these circumstances the understanding of the status of these species and developing mitigation measures will not only provide knowledge about the species but also receive support from the local communities for their conservation. Secondly, when there is a constraint of time and other resources or manpower, there is a need to identify a robust way of collecting information and this is possible only through adopting all existing methods or through developing new approaches to data collections (Varman and Sukumar 1995; Varma 2000).
Our initial interest was to evaluate methods that could be followed and eventually be used to assess the status of forests and the relative abundance of wildlife, particularly mammals. Our interest was restricted by the constraints imposed by the landscape features, availability of time and other resources, and non-availability of specific methodologies. However, these limitations did motivate us to identify methods for documentation, compare and review methodologies adopted, and numbers reported from similar landscapes elsewhere. A review and comparison of methodologies adopted provided us with insights into the merits and demerits of each methodology, and comparison of the results with other regions helped us in identifying the accuracy of the knowledge that was gained through this short-term survey.