The relationship between invasive aquatic plants, cyanotoxins, and freshwater turtles in the southeastern United States

We explore how the invasive aquatic plant Hydrilla verticillata may impact freshwater turtles. We used a laboratory feeding trial to show that painted turtles (Chrysemys picta) could develop vacuolar myelinopathy (VM), a neurologic disease caused by an undescribed cyanotoxin produced by a cyanobacterium commonly found on Hydrilla. We also estimated patch occupancy patterns of turtles in five reservoirs to determine if Hydrilla invasion affects turtle habitat use or abundance. Hydrilla was positively associated with the detection probability of painted turtles and yellow-bellied sliders (Trachemys scripta) and positively associated with patch occupancy of common musk turtles (Sternotherus odoratus), indicating Hydrilla density is likely positively influencing patch abundance of these three turtle species. Hydrilla was not correlated with detection or occupancy of common snapping turtles (Chelydra serpentina). These results suggest Hydrilla is positively affecting habitat use or abundance of turtles inhabiting reservoirs; however, if occupancy of Hydrilla invaded habitats increases turtle exposure to cyanotoxins, then Hydrilla invasions may be creating an ecological trap for turtle populations.