Avon Bottoms

State Natural Area (No. 36)

Location: Within Avon Bottoms Wildlife Area, Rock County. T1N-R10E, Sections 21, 27, 28. 168 acres.

Access: From the intersection of County Highway K and Beloit-Newark Road in Newark, go west on Beloit-Newark Road 4 miles, then south on Nelson Road 1.6 miles to a parking area east of the road and south of the Sugar River. The natural area lies north of the river and west of Nelson Road.

Description: Avon Bottoms features a lowland hardwood forest in the floodplain of the meandering Sugar River. Large silver maples, swamp white oaks, and green ash dominate the diverse canopy of this wet-mesic forest. Other tree species are shagbark hickory, hackberry, cottonwood, bitternut hickory, bur oak, American elm, and basswood. Sycamores, at the northern limit of their range, are occasionally present and black willows are common along the river. The forest contains a rich herbaceous and shrub layer with many southern-ranging species found at their northern range limit here. Common shrubs are buttonbush and dogwoods and poison ivy is abundant in two forms –shrub and climbing vine. Other common lianas include wild cucumber, river grape, woodbine, and common moonseed. The composition of the understory differs from other Wisconsin floodplain forests due to the presence of rare southern-ranging species including wild chervil (Chaerophyllum procumbens), and obovate beak grain (Diarrhena obovata). There are a number of oxbows – temporary pond areas made by the cut-off of old stream meanders – along with running sloughs and potholes, which all harbor unusual reptiles, amphibians, and invertebrates. Bird life is diverse with blue-gray gnatcatchers, tufted titmice, blue and green winged teal, and wood ducks. Rare species include yellow-throated (Dendroica dominica), cerulean (Dendroica cerulea), and prothonotary warblers (Protonotaria citrea), yellow-breasted chat (Icteria virens), yellow-crowned night heron (Nycticorax violaceous), blanchard’s cricket frog (Acris crepitans blanchardi), riverine clubtail (Stylurus amnicola) and russet-tipped clubtail dragonfly (S. plagiatus). Avon Bottoms is owned by the DNR and was designated a State Natural Area in 1958.