India, Oct. 10 -- Some fixes can backfire in a big way. In New Zealand, a hardy grass was introduced to turn marshy coastlines into grazing land. It eventually took over parts of the coast. In February 2025, New Zealand's Department of Conservation (DOC) issued a media release. Cordgrass, or spartina, was planted across the country in the 1940s to stabilize land for reclamation projects. Now, the agency calls it an aggressive and long-lasting invader of tidal mudflats. That's a big change for a once helpful plant.

Spartina is a fast-growing, salt-tolerant plant that can grow to be two meters tall. These features appealed to settlers who wished to create more cultivable land areas. It seemed like an ideal strategy since all the plant need...