Fire alters diversity, composition and structure of dry tropical forests in the Eastern Ghats

Fire is known to have dramatic consequences on forest ecosystems around the world, and on the livelihoods of forest-dependent people. While the Eastern Ghats of India have high abundances of fire-prone dry tropical forests, little is known about how fire influences the diversity, composition and structure of these communities. Our study aims to fill this knowledge gap by examining the effects of presence and absence of recent fire on tropical dry forest communities within Kadiri watershed, Eastern Ghats. We sampled plots with and without evidence of recent fire in the Eswaramala Reserve Forest in 2008 and 2018. Our results indicate that even though stem density increases in the recently burned areas, species richness is lower because communities become dominated by a few species with fire resistance and tolerance traits, such as thick bark and clonal sprouting. Further, in the presence of fire, the size structure of these fire-tolerant species shifts towards smaller-sized, resprouting individuals. Our results demonstrate that conservation actions are needed to prevent further degradation of forests in this region and the ecosystem services they provide.

Methods
At each sampling location, we sampled circular plots of 10m radius. At each plot, all individuals of tree species of basal girth >2cm were identified and counted in both 2008 and 2018. In 2018, we measured size of every stem. In 2008, there were 9 sampling locations with 2-6 plots in each location, each plot separated by a minimum of 100 m. In 2018, there were 10 locations, each with 2-8 plots separated by a minimum of 100 m. We include plots that are atleast 500m away from the nearest human habitation and have atleast two individual tree stems. We document evidence of recent fires by visual estimation of plots.