AMPHIBIANS

Amphibians are tetrapod vertebrates first appeared on the earth nearly 360 million years ago. Amphibians are one of the best bioindicators as they respond to the minute disturbances in their habitat or in the environment. Their relatively wide distribution, bimodal life style (aquatic tadpole and terrestrial adults), ectothermic conditions with stable environmental temperature of 20-30°C and moist permeable skin have made them highly sensitive and susceptible to the external changes. Amphibians are pivotal organisms both as prey and predator in many food chains and constitute a vital component of the ecosystem. In ecosystem management, they are the best biological pest controllers.

Amphibians are present in many habitats and microhabitats. They can be found inside the water, muddy and rock crevices, burrowing deep in the soil, or bushes, high canopy trees etc. Amphibians are a plenty during rainy season, as they require water to breed and to lay eggs. Majority of the amphibians are active during night (nocturnal). Amphibians are well known for their croaking noises (vocal calls), which they generally do to attract the partner. One can easily locate and identify the amphibian species based on their calls.

(http://wgbis.ces.iisc.ernet.in/biodiversity/sahyadri_enews/newsletter/issue6/index.htm)

General outlook

Fig. 6. Body parts of a Frog

Some common Genera

Fig. 7. Some commonly observed genera of frogs in the Western Ghats

The forest official at the forester and guard level were trained in amphibian sampling in streams of Nagazari valley. Table 8 lists the observed anuran species during the past three years of study in the area.

Method

Time constrained sampling: # of man hour search in all-most-all micro habitats. The sampling is done in torch light preferably in late evenings. Usually a search for half an hour by two individuals that is a total of one man hour is sufficient for sampling.

Data Sheet for Amphibian survey
Date:
Time (start):
Time (End):
Latitude:                                  Longitude:                                  Altitude:
Land-use (major):  Agriculture/           Pond/   stream/              Evergreen/    Deciduous/      Grassland/     
Air temperature:                                              Water temperature:
Relative humidity                                             Canopy cover:
Asphalted road nearby

Table 8: List of amphibians found in DATR during 2006-2009

• IUCN 2008. 2008 IUCN Red List of Threatened Species. <www.iucnredlist.org>. Downloaded on 18 February 2009.
• Note: the list includes the species encountered during monthly surveys carried out earlier and during 13-15th February 2009.