“You can see an ecosystem change overnight – especially with hydrilla. You’ll see a normal pond, and then at the end of the growing season, it will be completely filled with hydrilla,” said Nicole White, founder of . Little Bear Environmental ConsultingWhich often works with city and state departments to deal with invasive species. “Nothing else can survive there. It is suffocated.”
White worked in partnership with other organizations including the Department of Environmental Protection Eradication of hydrilla in the Croton River from 2018 to 2022. Of the 449 sites they initially sampled, hydrilla was present at 40 percent.
Ultimately, he successfully destroyed hydrilla from the bottom three miles of the river using very low concentrations of herbicide for five seasons, but the impact of hydrilla on the river's ecosystem was so severe that at the end of the project, White had to remove several The natives had to be resettled. Aquatic plants in the Croton River.
According to Taylor, hydrilla still remain in the New Croton Reservoir. The Department of Environmental Protection is also using herbicides to replace it.
The presence of hydrilla in a reservoir can impact not only the marine ecosystem, but also water quality and the survival of local birds. Hydrilla is also known to contain cyanobacteria, which can turn into a toxin.Aetokthonos hydrilicola. This type of harmful algae can kill waterfowl and bald eagles, and has the potential to harm human health.
“It's a neurotoxin, so in places where Aetokthonos A lot of wildlife have died from brain lesions that have been found on hydrilla,” White said. “So fish died off, reptiles like turtles died off, waterbirds that eat hydrilla died off, and then the predators of those waterbirds died off.”
Climate change causes warmer weather in the fall and extreme rainfall events that carry sediment around in the water column. This creates better conditions for hydrilla, cyanobacteria blooms and, by proxy, the spread of these toxins. Their presence has not been confirmed in New York State, although the Department of Environmental Protection is sampling for it.
Water flea, a looming threat
The fishhook water flea was found in the reservoir last year. The newness of its arrival means that Department of Environmental Protection officials have not yet observed adverse effects on the marine ecosystem, and its wider implications for the food chain are unknown. Water fleas can affect water quality by eating large amounts of zooplankton, which creates better conditions for the growth of harmful algae. Taylor believes it was probably transferred via fishing gear because water flea eggs can survive drying for long periods of time.
Like zebra mussels, once they have established themselves, it is almost impossible to completely rid a water body of fishhook water fleas. The most important thing for many scientists is often preventing their spread into new waterways – about 40 percent of New York's fresh water is connected by canals, making it very easy for species to move around.