Killed in cold blood: Amphibians and reptiles are bearing the brunt of crop intensification

Subject : Environment

Section: Pollution

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 the dispersal of seeds and in pollination—there are almost 40 species of lizards including skinks and geckos that are efficient pollinators.
Threats to this herpetofauna:
- increased use of pesticides and fertilisers,
- land conversion,
- changes in cropping systems and
- the reduced proportion of natural vegetation.
- 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 are most threatened in India followed by USA and China.

Why are they threatened?

Being cold-blooded they are extremely sensitive to microclimates (with a narrow range of soil humidity, moisture, light flux, acidity, air and soil temperature) and microhabitats (they have small habitats like grass cover and low dispersal range; maximum lifetime dispersal for frogs and toads is 12 km). This makes them particularly susceptible to agricultural intensification.
Researchers found that in areas where the diversity of the frog population is lesser, the numbers of beneficial arthropods have reduced due to intraguild predation—a phenomenon where more than one species feed on the same prey and therefore competitors feed on each other.