Mapping and Estimating Expansion Rates of Arundo Donax in Native Fish Conservation Areas of Central Texas
Date
2024-05
Authors
Carpenter DeMent, Jenna Marise
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Abstract
Invasive species management is often hindered by delays in detection or knowledge gaps of species-specific expansion rates. When monitoring is irregular, disturbed and even protected natural areas become more vulnerable to advancing invasions. Monitoring requires labor intensive surveys, sometimes in remote locations, costing time and resources that could otherwise be used in treatment stages. As small Unmanned Aerial Systems (sUAS) and accessible satellite imagery become available to land managers and researchers, avenues have been created for early detection of conspicuous invasive species. My aim was to map and assess the expansion rate of Arundo donax. A. donax poses a significant threat to the designated Native Fish Conservation Areas (NFCAs) of Texas where its tall stature and high biomass production threatens to alter water flow and its competitive propensity leads to decreased local native diversity. High resolution multi-spectral imagery collected around known populations of A. donax permitted the isolation of the species’ unique spectral response. This spectral response was compared to satellite imagery with greater coverage –Sentinel-2– for the development of a classification map encompassing a 200 m buffer of riparian zones within several targeted NFCAs across Texas. Our model performance encountered some difficulty, attributed to variation of soil reflectance and vegetative seasonality, but performs acceptably within two Central Texas NFCA for the 2022 classification (overall accuracy: 71%, kappa: 0.46). These NFCAs have been emphasized for investigation of A. donax’s expansion rate. Expansion rates were highest in the Southern Edwards Plateau, increasing ~ 0.284 km2/year. Project products of the first remote sensing-based map of Arundo within these NFCAs, as well as elucidated expansion rates, will benefit land management agencies. Methodology for continued detection and reevaluation of expansion rates may be replicated in the future for identification of priority treatment areas.
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Keywords
invasive species mapping, Arundo donax, giant reed, native fish conservation areas
Citation
Carpenter DeMent, J. M. (2024). Mapping and estimating expansion rates of Arundo donax in native fish conservation areas of Central Texas (Unpublished thesis). Texas State University, San Marcos, Texas.