Using paleoecology to inform landscape management in the Nilgiris Biosphere Reserve

Speaker : Dr. Ramya Bala Prabhakaran

Abstract: The antiquity of the grassy tropical biomes of India is at the centre of a debate on whether they are degraded forests created by anthropogenic fires or a savannah with a natural long-term relationship with fires. Current day management of such forests has almost entirely followed a fire suppression policy, in line with colonial legacies. Indigenous knowledge systems however, hint at the use of fires as management tools to retain ecosystem functions considered favourable which we discuss further in the study.  We use paleoecology to inform this debate by arriving at evidence-based understanding of interactions between climate, vegetation, fires and humans in the fossil record in the Nilgiris Biosphere Reserve. I will present work from 2 sites - a high-elevation shola-grassland mosaic and a mid-elevation dry tropical forest in the Mudumalai Tiger Reserve (MTR). The high-elevation peatland preserving ~50,000 years is a candidate for an alternative stable states framework, showing switches between vegetation states with fire and human presence.  The sediment profile from MTR preserves ~1200 years showing drier conditions developing at ~600 BP (1350 CE) with a gradual shift to a more grass signal, and a complete shift to grass dominance at ~350 BP (1600 CE) associated with an increase in charcoal particles. We conjecture the gradual shift at 1350 CE could be indicative of climatic change whereas the 1600 CE change is indicative of anthropogenic impacts due to the synchronous increase in fires. Our study shows the possibility that these landscapes may have been co-created by traditional indigenous communities, and we need to study these inter-dependencies and how they played out in the past to understand how to conserve these landscapes better. I will also introduce some of our ongoing work in trying to bridge the gap between paleoecology and neoecology to create models with predictive capabilities.