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Habitat Description

Environmental Setting

Ecological and Natural Resource Values of Humbug Marsh

Habitat Description

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Source: U.S. Fish and Wildlife Service

Vegetation on the island is mainly upland forests at the northern tip descending to cottonwoods and then emergent marshes at the southern tip. The shorelines of the island and mainland consist of steep drop offs with exposed sandy faces, as well as scattered emergent marshes. Large areas of emergent cattail marsh are also concentrated at the mouth of Handler Drain and near the northern portion of the mainland. Open water areas between the mainland and the island and adjacent to the east side of the island average about one to four meters in depth and support dense stands of mostly wild celery (Valisneria americana), and lesser amounts of water stargrass (Heteranthera dubia), waterweed (Elodea canadensis), the exotic Eurasian watermilfoil (Myriophyllum spicatum), and an exotic macroalga, (Nitellopsis obtusa) (Great Lakes Science Center, Unpublished data from September 2, 1998 and October 8, 1996). The uplands on the project site are a mixture of red and white oak, hickory, tulip tree, and black cherry with an understory of gray dogwood, honeysuckle and hawthorne. Several of the oak trees on the project site are at least three feet in diameter.

A multitude of fish, wildlife, wetland plants, and other aquatic organisms depend on globally rare and unique habitats such as those in the project area. The marsh habitats of the project site contiguous with the Detroit River are Great Lakes coastal wetlands containing all forms of coastal marsh communities, including wet meadow, strand, and emergent and submersed, aquatic macrophytes in a restricted riverine, geomorphological setting (Maynard & Wilcox 1997). They are the last remnant of Great Lakes coastal wetlands that were contiguous and up to a mile wide along the entire 32 miles of Michigan mainland shoreline of the Detroit River in 1815 (Afsislamb 1815). Such coastal wetlands have been reduced in the Detroit River by shoreline modifications to less than 3% of that present in the 1800s (Manny et al. 1988; Manny 1998a).

References:

Afsislamb, W.F.W. Owen K. 1815. A survey of the River Detroit from Lake Erie to Lake St. Clair. Map. 1 p.

Manny, B.A., T.A. Edsall, & E. Jaworski. 1988. The Detroit River, Michigan: an ecological profile. U.S. Fish Wildl. Serv. Biol. Rep. 85 (7.17). 86 pp.

Manny, B.A. 1998a. Ecological restoration of Grassy Island and the Wyandotte National Wildlife Refuge in the Detroit River. pp. 18-21 In: Tulen, L.A., J.H. Hartig, D.M. Dolan, & J.J.H. Ciborowski (eds). Rehabilitating and Conserving Detroit River Habitats. Great Lakes Institute for Environmental Research, Occasional Publication No. 1, Windsor, Ontario. 65pp.

Maynard, L. & D. Wilcox. 1997. Coastal wetlands of the Great Lakes…State of the Lakes Ecosystem Conference ’96. U.S. Environmental Protection Agency, EPA 905-R-97-015b, 99 pp.

Region 3, U.S. Fish and Wildlife Service
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Fort Snelling, MN 55111
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Dr. John H. Hartig, Refuge Manager
Detroit River International Wildlife Refuge
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Grosse Ile, MI 48138
Phone: 734-692-7608 Fax: 734-692-7603
E-mail: john_hartig@fws.gov

Last updated: July 9, 2008

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Vegetation on the island is mainly upland forests at the northern tip descending to cottonwoods and then emergent marshes at the southern tip. The shorelines of the island and mainland consist of steep drop offs with exposed sandy faces, as well as scattered emergent marshes. Large areas of emergent cattail marsh are also concentrated at the mouth of Handler Drain and near the northern portion of the mainland. Open water areas between the mainland and the island and adjacent to the east side of the island average about one to four meters in depth and support dense stands of mostly wild celery (Valisneria americana), and lesser amounts of water stargrass (Heteranthera dubia), waterweed (Elodea canadensis), the exotic Eurasian watermilfoil (Myriophyllum spicatum), and an exotic macroalga, (Nitellopsis obtusa) (Great Lakes Science Center, Unpublished data from September 2, 1998 and October 8, 1996). The uplands on the project site are a mixture of red and white oak, hickory, tulip tree, and black cherry with an understory of gray dogwood, honeysuckle and hawthorne. Several of the oak trees on the project site are at least three feet in diameter. A multitude of fish, wildlife, wetland plants, and other aquatic organisms depend on globally rare and unique habitats such as those in the project area. The marsh habitats of the project site contiguous with the Detroit River are Great Lakes coastal wetlands containing all forms of coastal marsh communities, including wet meadow, strand, and emergent and submersed, aquatic macrophytes in a restricted riverine, geomorphological setting (Maynard & Wilcox 1997). They are the last remnant of Great Lakes coastal wetlands that were contiguous and up to a mile wide along the entire 32 miles of Michigan mainland shoreline of the Detroit River in 1815 (Afsislamb 1815). Such coastal wetlands have been reduced in the Detroit River by shoreline modifications to less than 3% of that present in the 1800s (Manny et al. 1988; Manny 1998a).