Soil, geomorphology and pre-European settlement vegetation associations of Southwest Louisiana

Dates

Publication Date: 2017-07-31
Time Period: 1849-12-31

Citation

Baldwin, H.Q., and Allain, L.K., 2017, Soil, geomorphology and pre-European settlement vegetation associations of Southwest Louisiana: U.S. Geological Survey data release, https://doi.org/10.5066/F7BC3X18.

Summary

Defining the pre-European range of vegetation communities can enhance our understanding of the role soil, hydrology, and climate had on climax plant communities within southwest Louisiana. Coastal prairie grasslands were in a perpetual state of succession due to two primary disturbances; grazing, primarily by bison and other ungulates, and fires ignited by lightning and Native Americans. Along its borders, prairie vegetation blended into adjacent plant communities forming biologically diverse ecotones that may have fluctuated between a prairie, marsh, or forest dominated community as a result of variable conditions including climate cycles, disturbance and soil characteristics. Since European settlement, this landscape has undergone [...]

Summary

Defining the pre-European range of vegetation communities can enhance our understanding of the role soil, hydrology, and climate had on climax plant communities within southwest Louisiana. Coastal prairie grasslands were in a perpetual state of succession due to two primary disturbances; grazing, primarily by bison and other ungulates, and fires ignited by lightning and Native Americans. Along its borders, prairie vegetation blended into adjacent plant communities forming biologically diverse ecotones that may have fluctuated between a prairie, marsh, or forest dominated community as a result of variable conditions including climate cycles, disturbance and soil characteristics. Since European settlement, this landscape has undergone dramatic change with less than 1% of intact coastal prairie remaining. Conservation entities across the Western Gulf Coastal Plain are taking a collaborative, strategic, landscape scale approach to to conservation to enhance biotic and abiotic communities including pollinators.
This effort encourages communication and implementation of restoration and habitat enhancement actions within water sheds. We have produced a spatial dataset which considers landscape position and soil type, based on Soil Survey Geographic Database (SSURGO) data, to predict appropriate vegetation associations for plantings across southwest Louisiana based on expert elicitation, and historic references. Methods to produce this product begin with soil boundaries and identification information using Map Unit Keys (MUKEY) which were gathered from SSURGO data (Soil Survey Staff, NRCS 2017). Each mukey number was reviewed on the SOIL WEB to obtain information about components. Components include the proportion and general geomorphic features associated with soil series. Natural vegetation associations were examined and documented for each soil series individually using multiple references, including USDA Soil Series descriptions, expert elicitation, and historical spatial references. Professional reference maps contributed to this spatial dataset and include an 1863 work by Henry L. Abbot and numerous General Land Office surveyor maps and surveyor descriptions from the early 1800s drawn at the scale of a township. General vegetation categories associated with Soil Types (Mukey) were derived from reviewing the vegetation associations of the dominant components, or soil series. These general categories include: anthropogenic, prairie, transition, forest, marsh, swamp, uncertain, and water. Anthropogenic categories were generally due to significant dredging, or other industrial activities. Transitional areas included savannas and areas which may have significantly changed from prairie to forest dominated communities due to rainfall and/or fire frequency and intensity. Forest and swamp includes a range of forest types from which the distinction between these two categories primarily depend upon relative elevation and hydrology. There were a few soil series in which we are uncertain of their pre-settlement vegetation. These areas are anomalies on the landscape and include salt domes and old, disjunct river meanders which are largely comprised of Pleistocene soils and were most likely marais, yet currently much of it is heavily forested as bottomlands, and we are therefore uncertain if this result is solely due to absence of fire. Attribute data include MUKEYs within the parishes which are included in the Louisiana portion of the Gulf Coastal Plain Ecoregion. Information in the table includes symbols, common names, and components which were compiled from SSURGO dataset and Soil Web online resources (Soil Survey Staff, NRCS, accessed 2/2017). For more detailed vegetation associations for individual soil series, please refer to 'VegSoilAssoc_SWLA.pdf' or 'VegSoilAssoc_SWLA.csv'.

Contacts

Point of Contact :: Matthew J Cannister
Originator :: Heather Baldwin, Larry K Allain
Metadata Contact :: Matthew J Cannister
Distributor :: ScienceBase
USGS Mission Area :: Ecosystems
SDC Data Owner :: Wetland and Aquatic Research Center

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VegSoilAssoc_SWLA.csv	12.54 KB	text/csv
VegSoilAssoc_SWLA.jpg	265.9 KB	image/jpeg
VegSoilAssoc_SWLA.pdf	97.33 KB	application/pdf

Shapefile: VegSoilAssoc_SWLA.zip
VegSoilAssoc_SWLA.shp.xml Original FGDC Metadata	View	33.35 KB
VegSoilAssoc_SWLA.CPG		5 Bytes
VegSoilAssoc_SWLA.dbf		459.31 KB
VegSoilAssoc_SWLA.prj		167 Bytes
VegSoilAssoc_SWLA.sbn		4.25 KB
VegSoilAssoc_SWLA.sbx		356 Bytes
VegSoilAssoc_SWLA.shp		154.68 MB
VegSoilAssoc_SWLA.shx		3.61 KB
VegSoilAssoc_SWLA.sld		5.5 KB

Purpose

Soil and hydrology are significant factors which can be used to predict optimal, climax, and pre-settlement vegetation communities, particularly differentiating between grasslands, marshes and forests. Many prairie plant species have a competitive advantage over other plant assemblages due to their physiological adaptations to drought conditions which are quickly simulated throughout Southwest Louisiana due to soil characteristics, despite the high rainfall amounts experienced in this portion of the country. Pairing plantings and management actions with appropriate soil conditions may minimize efforts necessary to reduce invasive species encroachment, and result in more vigorous vegetative growth with higher native diversity and productivity, thereby maximizing ecosystem services provided by conservation actions. The objectives and data syntheses of this project are to: Develop a geodatabase to a) identify the historical range of coastal prairie, b) identify areas of source pollinator populations, and c) rank areas to target for pollinator enhancement projects within the historical range of coastal prairie. We have done this by providing a spatial reference based on SSURGO soil data with a tabular dataset which includes soil components and associated geomorphic features to serve as a reference to a tabular dataset which further describes appropriate vegetation associated with each component, and producing a tabular reference which links to SSURGO spatial dataset. The tabular reference can be used to suggest appropriate conservation plantings based on details associated with soil type components and geomorphic features.

Soil, geomorphology and pre-European settlement vegetation associations of Southwest Louisiana

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