Mussel harvesting in the rich mussel beds of the uper Mississippi River has traken place since the early 1900s. Mussel shells were sold to the button industry until the widespread use of plastics after World War II. Since the 1960s, mussels have been harvested for export to Japan, where the shells are cut up and ground into round pellets and implanted into oysters to produce cultured pearls. Mussels are no longer abundant. Of the eighty species native to Illinois, more than half are threatened, endangered, extirpated, or extinct.

SIZE: 457,449 acres; 715 square miles

LOCATION: Northwestern Illinois along the Mississipi and lower Rock Rivers; Bureau, Henry, Lee, Mercer, Rock Island, and Whiteside counties

The Mississippi - Lower Rock River RRA includes major rivers, bottomlands, upland forests, prairies, and river bluffs. This RRA has a relatively high total acreage of Natural Areas due primarily to Mississippi River sites.

Bald eagles once commonly nested along the large rivers in Illinois. Declines in the continental population were reflected in the small number of eagles observed in Illinois from the late 1800s to the mid 1900s. Although nesting bald eagles are rare in Illinois, important wintering sites for bald eagels are found along the Mississippi and Illinois Rivers. Eagles which nest further north migrate to this area to feed on the fish below the dams where the turbulent water remains open even in the coldest winters. One important winter roost is just upstream from the Quad Cities at the Elton E. Fawks Bald Eagle Refuge Nature Preserve.

LANDCOVER: Cropland (54%) and grassland (18%) cover almost three-fourths of the land area. This RRA ranks 14th in percentage of bottomland woods, and 23rd in percentage of upland woods. Overall, woods accounts for almost 13% of the land area. This site has the fourth highest acreage and the ninth highest percentage of nonforested wetlands.

NATURAL AREAS : This RRA ranks third among the RRAs in terms of the Natural Area acreage. Four Mississippi River sites account for the majority of Natural Area acreage. The natural features found in the 17 Natural Areas in this RRA include prairies, marshes, aquatic features, and forests.

BIOLOGICALLY SIGNIFICANT STREAMS : Six BSS designations account for over 44 miles of BSS streams within this site. Three BSS segments occur on the Mississippi River and one on the Rock River.

HERITAGE SITES : This RRA has 74 Heritage occurrences. Of the ten significant community types, seven are prairies. Four plant species, 17 animal species, and six rookeries are found in this site.

STATE AND FEDERAL LAND : Within this RRA there are two state parks and one state fish and wildlife area. Federal land along the Mississippi River totals 15,694 acres.

NATURE PRESERVES : Three Nature Preserves occur within the site. Elton E. Fawks Bald Eagle Refuge is the largest (164 acres) and serves as an important winter roosting site for bald eagles. Black Hawk Forest is one of the few remaining areas representative of the narrow, forested bluff lines which characterizes the Middle Mississippi Border Natural Division.

NATURAL DIVISIONS : Seven natural divisions comprise this RRA. The Upper Mississippi and Illinois River Bottomlands is the predominant Natural Division (40%), followed by the Grand Prairie Division (22%) and the Middle Mississippi Border (20%).

SUMMARY OF SITE CHARACTERISTICS: SIZE, BIOLOGIC RESOURCES, AND PUBLIC LANDS