Plant Life in the Watershed
Plant life in the Lower Sugar River watershed has changed throughout the natural history of this diverse region due to climate fluctuations, weather events, and even the Native American’s use of fire to manage the land. However, the established balance and harmony of the plant communities changed dramatically when European settlers arrived in the 1800s. The immigrants began intensely farming the land—clearing wooded and forested areas, and cultivating large sections of the watershed. As a result, the grassland, forested, and wetland plant communities common to the area were drastically transformed. As of 2001, 79% of the watershed is now composed of cropland, pasture, and hay, with only 8% forests, 5% wetlands, and 1% grasslands, and 6% is developed.
Not only were natural plant communities greatly reduced by agricultural pursuits, but immigrants brought with them seeds and plants native to their countries of origin—many of which have become today’s invasive species. These invasives grow in the few natural communities that remain, and in disturbed areas such as roadsides, and even in your lawn!
Many of these invasive species have been here so long that we may not even recognize them as intruders. The roadsides are full of Queen Anne’s lace—the woods are loaded with garlic mustard, and homeowners wage war on dandelions every year! These are all plants brought over from Europe, and they have 
taken over and severely disrupted the native plant communities. When invasive species like garlic mustard invade natural plant communities, native wildflower populations suffer. Other invasives include dame’s rocket, honeysuckle, celandine, creeping Charlie, reed canary grass, and multiflora rose. The Wisconsin DNR has a section on its website about invasive species. Please educate yourselves about these left-over immigrants who are now posing a serious threat to our indigenous plants.
Natural Areas Remain
Luckily, examples of grassland, forested, and wetland plant communities in the Lower Sugar River watershed are found in both Wisconsin and Illinois. The Lower Sugar River corridor through the Avon Bottoms Wildlife Area in Rock County, Wisconsin is a floodplain and features lowland hardwood forests and wetlands. Two State Natural Areas, Avon Bottoms, and Swenson Wet Prairie reside within the wildlife area and are recognized for their rare intact plant communities. The Wisconsin DNR has information on both of these watershed gems.
Avon Bottoms
Avon Bottoms features a lowland hardwood forest in the floodplain of the meandering Sugar River. There is a wide range of tree species, look for the black willows that are common along the river. The understory plant community is different from other Wisconsin floodplain areas, due to the presence of rare southern-ranging species including wild chervil and obovate grain.
Swenson Wet Prairie
Swenson Wet Prairie lies in the low, flat floodplain of the Sugar River near its confluence with Taylor Creek. The site contains an excellent example of a wet-mesic prairie and sedge meadow with low river bottom savanna and scrubs interspersed with shallow, abandoned river channels. Two state- threatened plants, prairie Indian plantain, and round-fruited St. John's wort occur here. The savanna was perpetuated through a long history of grazing and is now overgrown by shrubs and other woody species. Avon Bottoms is owned by the DNR and was designated a State Natural Area in 1958. It is also home to a diverse bird population, and definitely worth a visit!
Other State Natural Areas
Within the Lower Sugar River watershed, three other State Natural Areas are found in Wisconsin’s Green County. Visit Ward/Swartz Woods for an example of southern dry-mesic forest remnant, and with special permission, you can see Abraham’s Woods and Oliver Prairie, a small remnant dry prairie. To learn more about these special plant communities visit Wisconsin’s Department of Natural Resource website for natural areas.
In Illinois’ Winnebago County, the Sugar River continues its flow through sandy-bottomed floodplain before emptying into the Pecatonica River. Three forest preserves, Sugar River Alder forest preserve, Colored Sands forest preserve, and the Sugar River forest preserve exist to protect the upland forests, bottomland forests, swamps, and non-forested wetlands. For a more detailed description of the nature preserves in Winnebago County click here.
We are privileged to live in such a rich and diverse watershed—with forested and wooded areas, wetlands, prairies, and floodplains. Protecting and preserving our native plant communities in all of these areas is critical to the health of the watershed community as a whole.