Avian Responses to Chemically and Physically Manipulated Cattail Stands in aNorthern Prairie Marsh

摘要

Prior to the 193Os, common cattail (Typha latifolia L.) was the only member ofthis genus to inhabit the northern prairies and was uncommon in most shallow wetlands (Metcalf 1931). During the late 193Os and early 194Os, narrowleaf cattail (T. angustifolia L.) extended its range westward into the Dakotas and Manitoba (Smith 1967). Concomitant with the invasion of narrowleaf cattail was the establishment of a hybrid between narrowleaf and common cattail, T. X glauca (Godron). Because both narrowleaf cattail and its hybrid are better adapted to fluctuating water regimes than common cattail (McDonald 1955), these species invaded shallow prairie wetlands. During the next 50 years, both spread rapidly throughout much of the Prairie Pothole Region (PPR) (Smith 1967), often forming dense monotypic stands in semipermanent wetlands (Stewart and Kantrud 1971). The value of cattail-dominated wetlands to waterfowl and other avian species is diminished following invasion (Beule 1979; Kantrud 1986). Waterfowl and other bird species prefer wetlands with an interspersion of emergent cover and open water approximating a 50:50 ratio (Weller and Spatcher 1965; Weller and Fredrickson 1974; Murkin, Kaminski, and Titman 1982). Good interspersion increases dabbling duck use by providing visual isolation of conspecific pairs and may provide a cue to quality feeding habitat (Kaminski and Prince 1984).