A not all too sweet history of Sweeton Pond

 

    While I may be located about 300 miles from the Ozarks, it is close enough to consider when accurately assessing the vegetation history of my location, Saint Louis. Looking to the Ozarks can illustrate a greater understanding of the complex vegetation history of Missouri. A recent paper by Nanavati and Grimm research seeks to address this. Specifically, they tackle how the vegetation history of the Ozarks connects to historical anthropogenic forces. Nanavati and Grimm (2020) attempts to assess the human landscape alterations- primarily fire- and their influence on the vegetation history of Sweeton Pond (Fig. 1).

Sweeton Pond is an area in the Southern region of Missouri and the Ozarks. Quercus-Carya forests dominate the current landscape, and it was historically occupied by the Osage Native Americans. However, the colonization by Euro-Americans removed the Osage people. Thus, Nanavati and Grimm (2020) assess the relationship of both the Osage people and Euro-American colonizers when constructing the fire history and vegetation history.

Figure 1. Modified figure from Nanavati and Grimm (2020) illustrating the Ozarks region and the location of Sweeton Pond. Sweeton Pond (Star) Cupola Pond (Circle). The dark border marks the Ozark region.

Their work reconstructed the relationship between vegetation history and fire activity by utilizing pollen records and charcoal analyses, which conveyed species diversity and abundance concerning fire activity. They calculated the percentage of taxa based on the species diversity of pollen to approximate abundance and species diversity.  Their charcoal analysis demonstrated deviations of fire activity from the interpolated charcoal accumulation rate (CHAR) against the background charcoal accumulation rate (BCHAR), a positive residual defined fire activity. These methods, combined with sediment coring and lithology methods, allowed the creation of chronological zones or periods: the Pre-Osage, the Osage, and the Euro-American Periods (Fig. 2).

The pre-Osage period spanned from 1840 to 450 calendar years before present (cal. yr BP) and the climate was the primary driver of vegetation and fire activity. From 1840 to 660 cal. yr BP, Sweeton Pond had a dry and warming climate, but Sweeton Pond’s climate became cooler and more humid around 660 cal. This earlier timeframe of the pre-Osage contains increased pollen of littoral shrubs (Cephalanthus) and Poaceae taxa. The data suggest a lower water depth and the presence of prairie openings or oak savannas at Sweeton Pond. The cooler and humid conditions increased mesic taxa, Quercus-Carya forests, and they decreased both Poaceae taxa and littoral shrubs. Anthropogenic fire activity of this period was indistinguishable from that of natural disturbances, as the Osage had not yet settled at the Ozarks.

Fire activity and increased diversity and abundance of mesic taxa define the Osage Period, which spanned from 450 to 130 yr BP. Fire activity increased concurrently with the arrival and expansion of the Osage Native Americans. Nanavati and Grimm (2020) propose that the humid climate and fire activity favored the expansion of Pinus echinata, a fire-dependent species. The fire activity shaped the prior Quercus-Carya forests to Quercus-Carya-Pinus mixed forests.

The Euro-American period- 130 cal. yr BP to present- marked the removal of the Osage Native Americans, an event that altered both the fire history and vegetation history. The population growth and colonization of the Ozarks increased Ambrosia taxa and shade-intolerant species, as new methods of land use removed P. echinate. This threatened the heterogeneity of Sweeton Pond and the Pinus-Quercus-Carya mixed forests.

The work of Nanavati and Grimm (2020) recounts the history of the Ozarks, and it includes those whose histories are often excluded from the narrative. The land usage of the Osage peoples and Euro-Americans shaped the current landscape of Sweeton Pond. Colonization of the Ozarks resulted in the removal of P. echinata, and the removal of the Osage. When recounting all histories, it is important to prioritize all those vulnerable and whose stories are lost. The paper draws a comparison between the concurrent removal of the Osage peoples and the subsequent loss of P. echinata. Nanvati and Grimm (2020) perpetuates a human-centered narrative, whose goal is to better understand all aspects of the history of the land. Through focusing on those who have been written out of ecological history, the narrative shifts towards a  biological understanding that brings power back to both land and people.