Abstract
Northern Vietnam has a long history of human occupation, warfare, and agriculture; yet, the environmental consequences of human activity are poorly understood due to limited paleoecological records. Results from a terrestrial wetland sediment core from the tropical island, Quan Lan, in Ha Long Bay provide a local record of ecosystem responses to societal shifts due to warfare/instability and climate change. A multiproxy study, including pollen, macro charcoal, fecal stanols and geochemistry, suggests that native vegetation was abundant and low-level, subsistence wet-rice agriculture and burning were in practice during a time of increased monsoon intensity between 1150 BCE and 950 CE. Between 950-1450 CE, a trading and military port was established on Quan Lan Island which served as a major hub of southeast Asian trade and protected the mainland from Mongol invasions. During this period, population near the wetland declined to undetectable levels, rice agriculture declined, burning ceased, and disturbance species expanded. A simultaneous shift toward a more arid climate, with possible extended years of drought, occurred during the Medieval Climate Anomaly based on regional climate records. Without a reliable source of freshwater, rice production declined and/or was supplemented by trade. When the mainland capital near present day Hanoi moved south to Hue after 1450 CE, the port ceased operation. During this time, climate became wetter, and precipitation and surface water more reliable than before. Population near the wetland increased as did burning and rice agriculture. The research has implications for understanding the maintenance of tropical biodiversity amidst long-term human occupation, political unrest and climate change.
Highlights
Paleoenvironmental studies provide baselines for future environmental changes, especially in locations with long histories of human occupation and agriculture
Northern Vietnam is a region of high biodiversity, but which has a history of human occupation extending back at least to the late Pleistocene and agriculture expansion in the late Holocene (Goscha, 2014; Taylor, 2014)
Due to the lack of dates prior to ∼950 common era (CE), and the large age ranges and uncertainties, more confidence is placed on the last millennia, but data are presented for a comparative baseline
Summary
Paleoenvironmental studies provide baselines for future environmental changes, especially in locations with long histories of human occupation and agriculture. In biodiverse tropical locations, such studies are limited but necessary to document the sensitivity and recovery of tropical ecosystems impacted by human pressures and climate variability. Northern Vietnam is a region of high biodiversity, but which has a history of human occupation extending back at least to the late Pleistocene and agriculture expansion in the late Holocene (Goscha, 2014; Taylor, 2014). Information on the role of prehistoric human activities and climate change on northern Vietnam tropical environments is sparse. Paleoecological records that do exist for the region are reported for deltaic and estuarine environments, providing only broad-scale, regional, and continental interpretations (Li et al, 2006, 2009)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
