Ecological consequences of Pleistocene megafaunal declines in the Neotropics

The late Quaternary saw the loss of 2/3rds of the world's megafauna (herbivores > 45 kg). The late Quaternary extinctions began around 50,000 years ago and in some regions persisted into the Late Holocene or about 4000 years ago, with temporal variation across continents. Megafauna have vital ecological roles in ecosystems. The late Quaternary extinctions led to changes in vegetation, fire activity, and nutrient fluxes, with long-lasting effects on ecosystems. Understanding these impacts may help estimate the consequences of extinctions today and inform restoration and conservation. The Neotropics experienced major megafaunal declines (80%), however, data are scarce due to limited fossil sites. Spores of coprophilous fungi (SCF), which grow on herbivore dung, offer a valuable alternative for estimating megafaunal presence and decline. SCF succession is influenced by complex yet unclear factors, including seasonality. SCF are preserved with fossil pollen and charcoal and can help reconstruct vegetation and fire activity. Zoogeochemistry-acts of nutrient liberation, concentration and dispersal via animals-can offer insights into nutrient cycling. Multi-elemental analysis in sediment can be used to understand past nutrient changes in ecosystems. This PhD project will combine microfossils and elemental analysis of sedimentary archives to: improve understanding of SCF succession, herbivores, and climate in estimating Late-Quaternary megafaunal presence and declines. It will determine the timing of the Late Quaternary megafaunal declines in Panamanian and Colombian forests and investigate if changes in vegetation, fire activity, and zoogeochemistry occurred within these ecosystems after megafaunal declines.