Restoring neo-tropical dry ecosystems - is plant functional composition the key to success?

Abstract

Tropical dry forests and savannahs (TDFS) represent 34% of Brazil's land area and contain >50% of Brazil's plant species. However, <10% of Brazil's dry forest and <20 % of its savannahs remain intact, with only 1.2% of dry forests and 7.5% of savannahs protected. More than 100 million people live in the TDFS regions of Brazil and rely on the essential ecosystem services they provide, including: food-, economic-, social-, and water-security. Furthermore, the resilience of TDFS has been questioned by Earth system modelling studies suggesting increased drought threats arising from both climate-change and climate-extremes will adversely impact TDFS. Thus, it is vital that the long-term resilience of TDFS is understood to facilitate their restoration. The main aim of this research is to evaluate how functional composition is linked to TDFS restoration success, in order to improve tropical dry forest and savannahs (TDFS) restoration policy in Brazil and facilitate the creation of TDFS which are resilient to climate change. We will develop new understanding of how community-scale functional diversity is linked to: i) taxonomic and phylogenetic diversity and; ii) ecosystem resistance and resilience to environmental change across restored TDFS sites. Working at sites which span the various restoration strategies in TDFS, we will, in collaboration with the Brazilian governments Ministry for Environment and Ministry for Agriculture, develop new scientific knowledge targeted at the creation of new restoration policy within Brazil. We will achieve this through using plant functional traits, to understand how to create TDFS ecosystems which are "climate-smart", maximising the likelihood of long-term restoration success under current and future climates. We will test five key hypothesis, using cutting-edge scientific techniques, which will lead to globally important high-impact scientific output and a step-change in Brazilian restoration policy: H1: Maximum taxonomic and phylogenetic diversity is not synonymous with maximum functional diversity and ecosystem resistance in restored TDFS. H2: Restoration success varies with restoration strategy due to shifts in functional diversity. H3: Restoring plant communities with greater drought resistance reduces the risk of desertification and exotic invasion. H4: Exotic invasive grasses reduce the resistance of TDFS to drought.H5: Greater resistance to current climate extremes increases resilience to future climate change. (AU)