MSc

Bats though constitute the largest mammalian order in India; very little
studies have been done on them. This has resulted in a gap in our knowledge about the
very basic information about the distribution pattern and status of these mammals. This is
true for the bats of Kerala also. The present study to generate information on diversity of
bats in Peechi-Vazhani Wildlife Sanctuary was carried out during the period May 2002 to
April 2003.
A total of 384 mist net hours were spent, out of which 307 mist net hours
in moist deciduous and 77 mist net hours in evergreen habitats, in accordance with the
proportional area under the two habitats in the sanctuary.
The result of the study revealed that during the study period a total of 184
individuals of bats were collected through mist netting from Peechi-Vazhani Wildlife
Sanctuary. 18 bat species belonging to four families were obtained. This constitutes about
58.07 per cent of the bat species in Kerala and 15.93 per cent of the total bat species in
India. The bat families identified were Pteropodidae, Megadermatidae, Rhinolophidae
and Vespertilionidae. All the four species of the Kerala fruit bats (Pteropodidae) were
recorded from Peechi-Vazahni Wildlife Sanctuary. So also, both the species of the False
Vampire bats (Megadermatidae) present in Kerala were also obtained from the study
area. Of the other families maximum number of species (seven) was obtained for
Vespertilionidae followed by Rhinolophidae (five).
Out of the twenty locations selected for the study, Cynopterus sphinx and
Rhinolophus rouxii were found in nine locations each. Maximum number of species
representing all the four families was recorded during the present study from premises of
Peechi dam (eight) which is a moist deciduous area. Maximum numbers of individuals
were obtained from another moist deciduous habitat, Thamaravellachal and were
belonging to three different families. The species obtained were Cynopterus sphinx
(Pteropodiade), Rhinolophus rouxii (Rhinolophidae), Rhinolophus fulvus (Rhinolophidae)
and Megaderma spasma (Megadermatidae).
Cynopterus sphinx was found to be the most abundant species in the
Peechi-Vazhani Wildlife Sanctuary followed by Rhinolophus rouxii, Megaderma spasma,
Hipposideros speoris and Rousettus leschenaulti. The bat species Pipistrellus ceylonicus,
Pipistrellus affinis, Pipistrellus coromandra, and Kerivoula picta were showing the
minimum abundance (1).
The analysis of the data revealed that there is no significant variation in
bat diversity between the two habitats in Peechi-Vazhani Wildlife Sanctuary. Even
though there was no significant difference between the two habitats, a close perusal of the
data showed that maximum number of species was obtained from moist-deciduous
habitat (15). Moist deciduous habitat recorded 166 individuals. Evergreen habitat
recorded 18 individuals in six species.
Among the 18 species recorded from the sanctuary, Pipistrellus affinis and
Rhinolophus rouxii are near threatened species as per the IUCN criteria. The remaining
sixteen species are coming under the category least concern. Rhinolophus rouxii is the
second most abundant species in the sanctuary. Hipposideros speoris is endemic to south
Asia.
Small mammals with smaller area requirements would have been the last
one to be affected due to the changes in the landscape and habitat degradation. Smaller
mammals are susceptible to the alterations in the habitat and thus could be a good
indicator of the habitat health. The development of comprehensive inventories of key
vertebrate taxa such as bats derived from a combination of several standardized sampling
procedures is essential to develop meaningful, conservation oriented plans for land use
and management for protected areas. Conservation strategies may be improved if
information on species abundance pattern is taken into account.