Leucaena and Acaia leaf litter negatively affect the survivorship of tadpoles of the South Asian frog Microhyla ornata

Abstract

Leaf litter from terrestrial plants forms an essential source of organic food matter for many freshwater aquatic organisms. However, leaves of some species are known to alter water quality, affecting the development and survivorship of amphibians. While amphibians from North and South America are affected by terrestrial leaf litter, similar studies are missing from Asia, a region with high amphibian diversity (mainly from the south and south-east Asia). At different tadpole densities, we tested the effect of different leaf litter (two non-native trees and a grass species) on the survivorship of ornate narrow-mouthed frog tadpoles (Microhyla ornata), a common frog in South Asia. We found the tadpole probability of survival extremely low in Leucaena but high in Themeda. While the odds of survivorship were nearly twelvefold higher in Acacia than Leucaena, it was not as high as in Themeda. A tadpole also had a lower odds of survival if raised in a high-density environment. In addition, Leucaena litter water had significantly higher pH levels than other litter types. Since both Leucaena and Acacia are non-native trees actively grown for agroforestry in South Asia, our results highlight another potential threat to amphibians in this region. Given the high amphibian diversity in this region, there is an urgent need for similar studies on other anurans and aquatic organisms.