Preliminary analysis reveals sediment burial decreases mass loss and increases survival of the aquatic invasive plant Hydrilla verticillata following desiccation over short time scales

Aquatic plants represent a key target in the management of biological invasions due to their ability to outcompete native species, interfere with human water use, and modify nutrient cycles. Studying desiccation tolerance of aquatic plants can improve understanding of their survival in habitats with fluctuating water levels, as well as response of invasive aquatic plants to management practices such as drawdowns. In a preliminary study, using Hydrilla verticillata as a case study, we desiccated plant fragments for 3 hours on top of sediment, buried beneath sediment, and in the absence of sediment in laboratory mesocosms to quantify the effects of sediment burial on survival and growth upon reintroduction to a common aquatic environment. In the absence of sediments, fragments experienced the greatest mass loss during desiccation and highest mortality rates upon reintroduction to the aquatic environment. Burial decreased plant fragment mass loss during desiccation, and upon return to a common aquatic environment, buried fragments demonstrated rates of new growth indistinguishable from undried control fragments. Overall, our results suggest that the presence of sediments can play an important role in the ability of aquatic plants to withstand desiccation stress at short time scales. Future studies should consider longer time scales and conditions most representative of field settings, as an understanding of sediments can inform management practices aimed at the control and eradication of hydrilla and other invaders.