Survey and activity patterns of nocturnal mammals in a fragmented dry deciduous forest of Karnataka.
2644 April 2007 | ISSN 0973-2535 (Print edition); 0973-2551 (Online edition) ABSTRACT We used camera traps to record the presence and activity of nocturnal mammals in the Savandurga state forest, Karnataka during the monsoon and winter seasons. We recorded six species of mammals at the traps over the two seasons. These included among others the Sloth Bear, Leopard, Indian Gerbille and Common Palm Civet. Nocturnal activity was more in winter than in monsoon. There is a high level of human disturbance in the area that appears to influence the activity of animals. KEYWORDS Activity period, anthropogenic factors, camera trap, dry deciduous forest, nocturnal mammals Large diurnal mammals have been a focus of most ecological studies since their presence is easy to establish and their abundances can be estimated by standard protocols (Karanth & Nichols, 1998, 2002). On the other hand, small mammals are difficult to locate and their presence are hard to detect to derive any meaningful estimate of their abundance (Webbon et al., 2004). Camera traps are often used to get some estimates of these (Nichols & Conroy, 1996). There have however been a few studies to estimate nocturnal small mammal abundance using camera traps in India (Mudappa, 1998) and none from isolated forest patches. In southern Karnataka there are several fragmented forests that may harbour nocturnal mammal species, but they have not been documented. Activity periods of animals in the wild reveal interesting patterns of resource used by them. Such information is important to identify the basic ecological requirements of the species such as food, habitat, breeding, territoriality and predation pressure. Feeding activity periods are also influenced by anthropogenic factors that strongly affect animal movements and can make animals switch their feeding activity patterns from the normal mode (Bentley et al., 2000). Much work has been done on activity periods of large diurnal mammals (Van Schaik & Griffiths, 1996; Karanth & Nichols, 1998; Yasuda, 2004; Srbek-Araujo & Chiarello, 2005), but the smaller, especially nocturnal animals are poorly known and only anecdotal information exists (Jayakar & Spurway, 1968; Yin, 1979; Singh, 1982; Acharjyo & Patnaik, 1987; Ayyadurai, et al., 1987; Rozhnov & Rutovskaya, 1996; Ganesh, 1997). Most of the activities of these animals have been observed under captive conditions (Acharjyo & Tripathy, 1974; Acharjyo & Mohapatra, 1978; Price, 1984; Jhala, 1997). In this paper we focus on three objectives, namely, (i) to record the diversity of nocturnal mammals using camera traps, (ii) to compare the nocturnal activity of selected species during monsoon and winter seasons, and (iii) to determine the impact of human disturbance on animal activity