Now, the invasive species can be found in about six different spots with several more suspected. But Japanese stiltgrass is just one of the newest arrivals in what state officials say has become an unending race against invasive species. “Every invasive species we track comes with its own set of problems, and the list is only getting longer,” said Chad Hammer, invasive plant biologist with Maine’s Natural Areas Program. “The concern is that (invasive species) compound each other, and the combined effects are worse than the effects independently,” she said. Toni Pied, who works with the Maine Department of Environmental Protection’s Aquatic Invasive Species Program, explained that, much like some terrestrial invasive plants, humans are the main spreaders for invasive plants in lakes and streams.