Biodiversity in protected coastal wetlands along the west coast of Lake Huron

Abstract

Lake Huron protected (barrier-protected) wetlands occur within 1 km of the lake, in swales, interdunal ponds, and other shallow depressions. These wetlands are not directly connected via surface water to Lake Huron, although their hydrology is influenced by lake levels. Biodiversity in them has not been well documented. We compiled plant and animal species occurrence data from published and unpublished sources for the U.S. coast of Lake Huron. Many data sources were reports written by the authors and/or by scientists of the Michigan Natural Features Inventory. Species occurrence data were supplemented with data from published wetlands literature and dissertations and theses. We did not do a thorough compilation for Canadian wetlands and only added limited Canadian data from the “Ontario Great Lakes Coastal Wetlands Atlas”. We estimate that total species richness exceeds 1400 species with about an equal number of plants and animals (600–700 species each). We documented the occurrence of 466 macrophytes in Lake Huron’s protected marshes, fens, and swamps and estimated total plant species richness to be > 600. Invertebrate species richness was estimated to be 500–600 with more than half of these being macroinvertebrates (> 0.5 mm) and the remainder being microinvertebrates (< 0.5 mm). Vertebrate species richness was estimated to be > 200 as follows. Fish species richness was estimated to be < 10 because of low oxygen, periodic dry periods, and lack of surface water connection to Lake Huron. Amphibian species richness was estimated to be > 20 with 10 frogs and toads and 7 salamander species documented. Reptile species richness was estimated to be > 20 based on very limited data and published distribution maps with > 10 turtle species and > 10 snake species but no lizards in Lake Huron marshes (although 4–5 lizard species occur on sandy ridges near swale marshes). More than 50 mammal and 80 bird species were estimated to occur in protected wetlands. Occasional additional use by birds and other species combined with the addition of rare species as additional sampling occurs are likely to increase the number of vertebrate species to > 200.