Killed in cold blood

Surveys quantify the impact of crop intensification on frogs and reptiles; say loss of species and farm productivity inevitable

- DEYATIMA GHOSH

THE DEMAND for land for food production always results in an uncomfortable trade-off between agricultural expansion and species conservation. One can see an example of this tradeoff in paddy fields, whose unique combination of wet and drylands provide ideal habitats for amphibians and reptiles. These cold-blooded animals, together referred to as herpetofauna, provide immense ecological services. Frogs and toads, for instance, act as biological control agents by feeding on crop pests. Several salamanders and tadpoles of frogs help in controlling mosquito and mosquito-borne diseases by feeding on the larvae. They also help improve soil quality and aeration, aid in dispersal of seeds and in pollination-there are almost 40 species of lizards including skinks and geckos that are efficient pollinators. However, the diversity and abundance of these herpetofauna are rapidly declining with increased use of pesticides, fertilisers, land conversion, changes in cropping systems and the reduced proportion of natural vegetation. According to the International Union for Conservation of Nature (IUCN), 1,532 species of Anurans (frogs) and 825 species of reptiles in the world are critically endangered, endangered and vulnerable due to agriculture and its management practices. They appear to particularly threatened in India which has a high amphibian diversity-most of them are endemic to the region-and, as per the UN Food and Agriculture Organization, had the largest cropland area over the last decade, followed by the US and China.