Native American landscape modification in pre-settlement south-west Georgia

摘要

Our objective was to interpret the presence and magnitude of landscape modification by Native Americans on Georgia's southern coastal plain. Specifically, we aimed to understand how the Native American presence influenced the distribution of fire-tolerant, mast-bearing and fruit-bearing tree species in the fire-dominated landscape of south-west Georgia.Our study area was comprised of sixteen contiguous counties in the south-west region of Georgia, in southeast USA bordering the Atlantic, investigating the taxon Angiosperms and Gymnosperms native to the early landscape of this region.We used witness tree data collected during the early 1820s across sixteen modern-day counties to reconstruct pre-settlement forest composition, particularly pyrophillic trees that are well-adapted to tolerate fire, and mast- and fruit-bearing species. Wethen used geographic distribution models (Boosted Regression Tree) to interpret the presence and magnitude of landscape modification by Native Americans on Georgia's forested south-west plain.The pre-settlement distribution of pyrophillic and mast-bearing trees within our study area were best explained by a combination of environmental (topographic relief, proximity to riparian %pnes, and soil depth) and Native American factors (AUG = 0.64 and 0.66, respectively).However, the addition of Native American presence as predictors greatly increased the explanatory power of soft mast (fruitfbearing models (AUC — +0.17).Our results demonstrate that Native American activities had a measurable influence on pre-settlement plant communities in south-western Georgia. However, the effects of these activities on vegetative composition were most notable in the distributions offruit-bearing trees. In contrast, distributions of fire-tolerant and mast-bearing taxa were found to be largely explained by a combination of environmental and anthropogenic factors.