Latitude and Community Diversity Primarily Explain Invasion Patterns of Widespread Invasive Plants in Small, Subtropical Lakes

Within the study of aquatic invasive species, small aquatic ecosystems are often neglected, despite representing most global freshwater bodies. This study uses community composition and environmental and geographic factors to explain the occurrence of invasive species in small lakes in the southeastern United States. Four invasive species widespread in the southeastern United States were selected as the focus of this study: Alternanthera philoxeroides, Cyperus blepharoleptos, Panicum repens, and Triadica sebifera. The aquatic plant communities of the lakes were surveyed using littoral zone point sampling. Generalized linear models for each species were fit with the probability of occurrence (P occ ) as the response variable and Secchi depth, plant species diversity (α-diversity), point richness, perimeter, latitude, and longitude as potential predictors; all predictors were subjected to model selection to define the best-fit models. All best-fit models were strongly predictive with area under the receiver operating characteristic curve values > 0.80. Plant species diversity was positively correlated with P occ of A. philoxeroides, P. repens, and T. sebifera. Latitude was negatively correlated with P occ of P. repens and T. sebifera. Perimeter was negatively related to P occ of A. philoxeroides. Secchi depth was negatively related to the P occ of C. blepharoleptos. Although plant species diversity and latitude were most commonly predictive, P occ was usually explained by multiple predictors, suggesting that these relationships are best explained with multiple environmental factors.

This work was supported by the Mississippi Department of Environmental Quality and the Mississippi Aquatic Invasive Species Council through a grant provided by the United States Fish and Wildlife Service.

Peer reviewed