Morphological abnormalities in natural populations of common frogs inhabiting agroecosystems of central Western Ghats

Abstract

The present paper reports the abnormalities recorded among four species of frogs: Limnonectus limnocharis, L. keralensis, L. brevipalmata, and Tomopterna (Spherotheca) rufescens inhabiting forest, water bodies, agriculture (paddy) fields and coffee plantations. The survey and sampling was made over a period of three years in early post monsoon (October) of 2001, 2002 and 2003. Of 6,303 frogs encountered 229 were abnormal (3.63%). Among the four types of habitat, coffee plantation has a high incidence of abnormality (4.64%), followed by agriculture field (paddy) (3.98%) and water bodies (3.92%), while no abnormal frogs were recorded from surveyed forest sites. Among the four species, maximum abnormality was recorded in L. brevipalmata (8.92%) followed by T. rufescens (6.12%), L. limnocharis and L. keralensis (3.26% each). Excepting the forest, in all other sampling areas, large amount of chemical fertilizers and pesticides are being used. Therefore, we suspect chemical contamination as a factor causing the abnormality in this region, but this needs confirmation.