Non-native, invasive species threaten the biological diversity and value of all habitats at Eastern Neck NWR. Invasive species often out-compete native species because they lack natural ecological controls such as predators and disease. Phragmites and mile-a-minute (pictured left) are two examples of the more predominant invasive plant species found on Eastern Neck NWR. Other species include garlic mustard, Canada thistle, Japanese stilt grass, Johnson grass, and wineberry. The refuge uses a variety of methods to manage these invasive plant species, including herbicides, prescribed fire, mowing, and the introduction of natural predators. Animals can also be invasive. Mute swans are an example of an invasive wildlife species found on the refuge. Introduced from Europe and Asia, mute swans are aggressive birds which compete with native species for food and habitat.