Assessing Drought Trends within the Aransas National Wildlife Refuge




Porritt, Glenn E.

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Drought is classified as an environmental disaster that can have severe implications for agriculture, the economy and wildlife that winter in the Aransas National Wildlife Refuge (ANWR) in coastal southern Texas. Although previous research has analyzed drought within the ANWR using the Palmer Hydrological Drought Index, this study examined additional indices that more fully accounted for plant health, temperature, and precipitation. Specifically, this study examined drought trends between 1986 – 2020 since drought is one factor that can affect wildlife in the ANWR. Multiple drought indices were utilized, including the Precipitation Condition Index (PCI), Temperature Condition Index (TCI), Vegetation Condition Index (VCI), Scaled Drought Condition Index (SDCI), and Vegetation Health Index (VHI), to provide a comprehensive assessment of drought trends. Additionally, the relationships between drought and wetland salinity were explored to better understand if drought elevates salinity levels, which can further negatively impact wildlife. Although the Mann Kendall statistical trend analysis indicated that the results varied by season and drought index, the majority suggest that drought magnitude decreased over the study period in the ANWR. The salinity levels did not display a significant relationship with drought, which could potentially be due to temporal lags in the drought-salinity relationship. Overall, this study suggests that drought became less severe in the ANWR between 1986 – 2020.


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Aransas National Wildlife Refuge, Drought, Landsat, Trend Analysis, geodesy