Invasive species are defined as those species (both plant and animal) that are normally not native to an area that can cause economic or environmental harm or harm to human health.

Phragmites (Phragmites australis), also known as common reed, is an aggressive invasive plant that once established can form dense stands that crowd out native wetland vegetation. Phragmites currently occupies large areas on the Refuge and is the number one priority for invasive plant treatment and control.

The Refuge completed a Phragmites management plan in 2007. The entire Refuge was surveyed: Phragmites was found in all areas of the Refuge. The Refuge established a two prong goal for controlling Phragmites by 2015. Goals include: reduce amount of area occupied by Phragmites to ≤ 10% of total area in each wetland management unit and reduce amount of area occupied in water delivery canals and wetland dikes to ≤5% of linear area. The Refuge uses a combination of methods to control the spread and reduce the area occupied by Phragmites. These methods include, prescribed burning, mowing, cattle grazing (pictured above) and the application of herbicides. Click here to download the full Phragmites Management Plan or our Phragmites Fact Sheet.

Medusahead rye, an exotic annual grass, appeared on the refuge a few years ago. We have targeted this small infestation for eradication to keep it from spreading. So far we have been successful in our efforts to rid the refuge of this plant. We will replant the treated area to native grasses and continue to monitor to be sure that Medusahead does not return.

Other invasive plants that the refuge treats include salt cedar, Canada thistle, hoary cress, perennial pepperweed, poison hemlock, and dyer’s woad. Invasive animals occurring on the refuge include the American bullfrog and the common carp.