Wildlife Conservation Efforts

Herpetofauna and the Impact of crop pesticides

Note4Students

From UPSC perspective, the following things are important :

Prelims level : Herpetofauna , Intraguild predation

Mains level : Herpetofauna , ecological importance and threats

Herpetofauna

Context

  • 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 trade-off in paddy fields, whose unique combination of wet and drylands provide ideal habitats for amphibians and reptiles. However, Amphibians and reptiles are bearing the brunt of crop intensification.

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Ecological services provided by herpetofauna

  • Herpetofauna: Amphibians and reptiles are cold-blooded animals, together referred to as herpetofauna, provide immense ecological services.
  • As biological control agents: 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.
  • Efficient pollinators and improves soil quality: 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.

Threats faced by herpetofauna

  • Increased use of pesticides and fertilizers: 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.
  • Threatened by agriculture and management practices: 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.
  • Particularly threatened in India: They appear to be 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.
  • Being cold-blooded, amphibians and reptiles have unique physiological demands: 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. However, the researchers find a distinct difference in the way it affects amphibians and reptiles.

Survey to understand the impact of crop intensification

  • To understand the impact of crop intensification on the populations and diversity of herpetofauna, researchers from the University of Calcutta conducted a year-long survey of farm lands in Odisha’s Baleswar district.
  • Almost 90 per cent of the 250,550 hectares of cultivable land in the district is under paddy.

Did you know?

  • Baleswar district, of Odisha is known as “Rice bowl of the state”.

Comment if any place in your state is recognized as such

Findings of the Survey

  • Low diversity in high cropping intensity: The abundance of amphibians was almost half and their diversity was low in areas with high cropping intensity, pesticide application and low natural vegetation when compared with areas where less-intensive farming is practised.
  • Amphibians are more exposed to pesticides: The difference is because amphibians are more exposed to pesticide contamination than reptiles as their skin is highly permeable and performs both respiration and water uptake.
  • Species are going through an extinction debt: The researchers suggest the species are rather going through an extinction debt wherein there is a lag between the impact of agricultural intensification on them and their response to it.
  • Reptiles face a higher threat from conflicts with humans: The real impact of the current intensification of agriculture on reptiles would be felt much later. When compared with amphibians, reptiles like snakes face a higher threat from conflicts with humans. Encroachment of forest areas and misconceptions and myths result in the indiscriminate killing of snakes irrespective of them being venomous or harmless.
  • Intraguild predation: The researchers also find that in areas where the diversity of the frog population is lesser, the numbers of beneficial arthropods have reduced due to intraguild predation. If this reduction in populations of both predators continues, it will disrupt the natural system of suppressing crop pest abundance.

What is mean by intraguild predation?

  • A phenomenon where more than one species feed on the same prey and therefore competitors feed on each other.
  • For example, when one predator, like a lion, hunts and kills another predator, like a hyena, for food.
  • It’s when animals that are both hunters, compete against each other for the same prey.
  • It is just like how two kids might fight over a candy bar.

Way ahead

  • The study shows unless a threshold abundance of frogs is maintained, their impacts will be far from beneficial to agriculture.
  • Semi-natural and natural vegetation and buffer strips such as ditches, provide chances to increase numbers of alternate prey, intermediate hosts of target pests and increase the availability of nutritional plant resources.
  • Semi-natural patches are beneficial for arthropod communities and can raise their numbers to enhance crop pest regulation.

Conclusion

  • To optimize the benefits from existing farmland, the researchers recommend that biodiversity research be holistic so more organisms get targeted ecological services.

Mains question

Q. What are herpetofauna? Highlight the Ecological services provided by herpetofauna and discuss the threats faced by herpetofauna.

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