top of page
Water chestnuts versus curly-leaved pondweed: which will spread the fastest? Place your bets!

Our group studied two invasive species, the Water Chestnut (Trapa natans) and Curly-Leaved Pondweed (Potamogeton Crispus). Both are aquatic plants that spread swiftly and leech on local plant life. We hypothesized that the pondweed, which flourishes in low-light areas, will expand at an equivalent rate to the Chestnuts, which block out light when densely gathered at the surface.Using citizen data from iDigBio and iNaturalist, we compared the distribution area for both species from their introduction to the present. The data revealed the discovery of both invasive species and showed locations where the species started. Over several years, these species have grown and taken over large bodies of water across the Northeast United States. Contrary to our hypothesis, the Curly-Leaved Pondweed far outnumbered and spread faster than the Water Chestnuts. We postulate that the water chestnuts benefit from the curly pondweed, so as the number of pondweed increases, the water chestnuts follow. The rise in the pondweed would be because the species can survive colder temperatures while the water chestnut does not. In our graphs comparing the two species, as the colder weather comes, the water chestnut population decreases, and the pondweed remains as the species is able to live through the drastic temperature change.

Jason Brewster '25, Deziray Nieves '25
bottom of page