Reed canary grass is an invasive species that was originally planted for forage. In fact, it continues to be planted in some places despite its profound affect on native plant communities. While it is a native of Europe, it is also commonly thought to be native to parts of North America as well. However, the species has been cultivated for desirable characteristics such as aggressiveness and fast growth and these cultivated varieties have escaped to become the invasive species we see today.
Reed canary grass thrives in a high nitrogen, high turbidity environment. In areas where water is clear and nutrients are low and the native plant community is well established, natives can often hold their own. Unfortunately, the streams, lakes, and wetlands of southern Wisconsin usually contain water that is perfect for reed canary grass. The grass has strong and aggressive rhizomes and also produces significant quantities of seed. This allows it to invade into just about any environment where moist soil is present. However, it will also grow in uplands especially where nutrients are high.
Invasion by reed canary grass greatly reduces botanical and biological diversity of a wetland. Eventually, a wetland dominated by reed canary will be almost uniformly made up of that species. It is even capable of limiting tree regeneration in
riparian forests. To quote the guide referenced above, reed canary grass "decreases retention time of nutrients and carbon stored in wetlands, accelerating turnover cycles and
reducing the carbon sequestration capabilities characteristic of diverse plant communities. Although its effects on wildlife are not yet entirely clear, preliminary data
suggest that habitat specialist species (including several listed and protected species) are more adversely affected by reed canary grass dominance than habitat generalists."