Topographic and Climatic Influence on the Dynamics of Peat-Forming Ecosystems and Implications for Paleoenvironmental Reconstructions in the Antarctic Peninsula and Patagonia

Abstract Climate and topography have profound influence on the dynamics of peat-forming ecosystems through many abiotic and biotic factors that sustain growth, accumulation, and expansion of these ecosystems. Peat-forming ecosystems sequester large amounts of carbon in the biosphere, so understanding processes that affect their initiation, persistence and expansion is important for the global carbon cycle. Furthermore, peat-forming ecosystems can preserve archives of paleoecological and geochemical proxies for documenting and understanding ecosystem response to environmental change. However, there is heterogeneity in records from peat archives at a regional scale, which in part reflects the influence of microclimate or topography. In this dissertation, I present a range of evidence from the Antarctic Peninsula (64°S) and Patagonia (54°S) to show that topography and microclimate can affect processes such as peat initiation, species dynamics, plant productivity, carbon accumulation, surface feature formation and ecosystem expansion on the landscape. Recognizing and understanding the mechanisms behind these processes is important for paleoenvironmental reconstructions and interpretations of peat-based records in the Antarctic Peninsula and Patagonia. This work shows that even small differences in microclimate and microtopography will influence ecosystem processes and should be considered when interpreting paleoenvironmental records.