Water and Habitat Dynamics of the Mingo Swamp in Southeastern Missouri,

The present report describes surface water relations in a lowland hardwood wetland in the Upper Mississippi Alluvial Valley MAV. Water regimes were examined by sampling habitats within the Mingo Basin hereafter, Mingo Swamp in southeastern Missouri weekly from February 1981 to May 1983. Habitat changes within the Swamp were documented from 1880 to 1983. Habitats within the Mingo Swamp are distributed along elevational and water regime gradients. Lands below 335 ft mean sea level support primarily baldcypress and open-water habitats immediately surrounded by scrubshrub habitats. Live forests naturally flooded and green-tree reservoir occur at higher elevations 336-344 ft and composed 54 of all habitats in the Mingo Swamp in 1983, 59 in 1973, 63 in 1966, 67 in 1955, 63 in 1941, and 82 in 1880. Dead-tree habitats increased from 1 of the area before 1973 to about 5 by 1983. The live forest is dominated by even-aged stands mostly 30-40 years old of pin oaks Quercus palustris. Light gaps compose about 3 of the forest area. Scrubshrub, open marsh, and newly created dead-tree habitats usually contained some water 80 of the year and 65 of the growing season. Overcup oak Quercus lyrata habitats contained some surface water from November to April each year. Pin oak habitats were usually partly flooded from December to May but were seldom 100 flooded and rarely had surface water 20 cm deep. Light penetration of all waters was low and decreased with increased rainfall and flooding. Alkalinity and conductivity were lower than in most other North American wetlands. pH decreased in fall and winter. Waters flood lowland hardwood wetlands in three ways on-site rainfall and puddling, backwater flooding, and headwater flooding.