Large scale burning for a threatened ungulate in a biodiversity hotspot is detrimental for grasshoppers (Orthoptera: Caelifera)

Abstract

Habitat management strategies across the globe are often focusing on flagship species, such as large threatened mammals. This is also true for most protected areas of India, where large mammals such as the Tiger or Asian Elephant represent focal species of conservation management, although a shift towards other species groups can be observed in recent times. Prescribed burning is a controversially debated method to manage open habitat types. This method is practised as a tool to manage the habitat of the endangered Nilgiri tahr, Nilgiritragus hylocrius (an endemic goat) at a large scale (50 ha grids) in Eravikulam National Park of the Western Ghats (Kerala, India). However, the impact of prescribed burning on other biota of this unique environment in a global biodiversity hotspot has not been studied. We compared the impact of large-scale prescribed burning on grasshopper abundances in Eravikulam National Park with small-scale burning in Parambikulam Tiger Reserve from 2015 to 2018, to assess the impact of the different fire management practices of these reserves on this species-rich insect group. We observed a negative response of grasshoppers to burning of larger contiguous areas in terms of their recovery after fire events, whereas burning small patches in a mosaic pattern facilitated rapid recovery of grasshopper communities. Our results suggest that burning management can be optimized to benefit both, the flagship vertebrate species as well as species-rich invertebrate communities.