Mississippi Lake National Wildlife Area Management Plan: chapter 2

2. Ecological resources

2.1 Terrestrial and aquatic habitats

Mississippi Lake National Wildlife Area (NWA) is primarily wetland habitat consisting of McEwen Bay and its associated marshland and the north shore of the Mississippi River. Approximately one sixth of the NWA is hardwood forest, and another small section consists of 5 ha mowed meadow and old field that was former cropland and pasture.

The gently sloping terrain around the low-lying McEwen Bay varies from smooth in the north to irregular in the south (Soil Research Institute, 1966). The lower areas are marshland and open water suitable for migrating waterfowl and spawning fish. This diversity provides habitat for a broad range of species. Limestone outcroppings are exposed in upland areas. In the higher areas, the vegetation communities are composed of open meadows and some deciduous forest.

2.1.1 Wetlands

There are two wetland areas within the NWA. The largest area is the provincially significant "McEwen Bay Wetland" which is a 224 ha wetland on Mississippi Lake, and covers approximately 80% of the NWA (Environment Canada Canadian Wildlife Service (EC-CWS), 1984; Ontario Ministry of Natural Resources (OMNR), 1984). McEwen Bay is separated from Mississippi Lake by a large island and peninsula at the mouth of the bay, and the wetland is comprised of emergent marsh (50%) and shrub thicket (50%) (EC-CWS, 1984; OMNR, 1984). The water in McEwen Bay is relatively shallow, exhibiting an average depth of about 1.5 m (Mohr and Maltby, 1985). The bottom is muddy, with loose vegetative debris and silt covering much of its surface. A very lush growth of aquatic plants can be found along the shoreline of the bay, between the open water and rooted aquatic submergent plants. Vegetation including Elodea (Elodea canadensis), Coontail (Ceratophyllum demersum), Water Celery (Vallisneria Americana), Wild Rice, Pondweed (Potamogeton natans), Yellow Pond Lily (Nuphar variegatum)and non-native Eurasian Milfoil (Myriophyllum spicatum L.) line the shore (Figure 5; Burns, 2003). During high water years, Wild Rice is the most abundant emergent to be found, forming extensive beds along the shore of the bay and river. Broad-leaf Cattail (Typha latifolia) occurs in the bay; however, few dense cattail stands are present. Flooded scrub, or more specifically willow-dogwood-maple thicket, dominates the land surrounding the bay. In some areas, this community is replaced by Silver Maple (Acer saccharinum) swamp at the water interface.

The second wetland area within the NWA is approximately 6 ha, and is part of the riverine wetland that extends along the north shore of the Mississippi River upstream from Mississippi Lake and is part of the "Innisville Wetlands Life Science Area of Natural and Scientific Interest (ANSI)" (OMNR, 2012). This small wetland area is composed of deciduous swamp and shallow marsh vegetation communities, providing a variety of habitats and connectivity to wetlands and uplands immediately adjacent to the east, and along the Mississippi River (The Nature Conservancy of Canada [NCC], 2008). The deciduous swamp consists of trees such as Silver Maple and shrubs such as Red-osier Dogwood (Cornus sericea), and the shallow marsh consists mostly of Broad-leaf Cattail and areas of shallow open water.

2.1.2 Upland forest

The upland forest is characteristic of the surrounding area. The forest is second growth, and forest patches are dominated by deciduous tree species. Within the NWA, Sugar Maple deciduous forest grows on dry land adjacent to the shrub thicket and marsh areas west of McEwen Bay and along the north shore of the Mississippi River (Figure 6; Hamill, 2009; White, 2008).

The forest is moderately mature, with little recent disturbance (Hamill, 2009; White, 2008).  The canopy varies widely from open to closed and is comprised of Sugar Maple (Acer saccharum), Basswood (Tilia americana), White Ash (Fraxinus americana), White Elm (Ulmus americana), American Beech (Fagus grandifolia), White Birch (Betula papyrifera), Eastern Cottonwood (Populus deltoides), Eastern White Cedar (Thuja occidentalis) and Balsam Fir (Abies balsamea) (Hamill, 2009; White, 2008). This community supports a small population of the endangered Butternut (Juglans cinerea). There is limited undergrowth, no clear dominance in ground flora, containing typical spring flora including Blue Cohosh (Caulophyllum thalictriodes), White Trillium (Trillium grandiflorum) and Wild Lily-of-the-Valley/Canada Mayflower (Maianthemum canadense) (Hamill, 2009), which are indicator species for undisturbed undergrowth (Keddy and Drummond, 1995). Non-native plant species are found primarily in disturbed areas along trails (Hamill, 2009; White, 2008).

2.1.3 Old field and meadow

Old field and meadow habitats are located along the extreme west side of the NWA (Figure 2; White, 2008). These areas were formerly pasture and farmlands and have been recolonized by native shrubs and trees (For example Trembling Aspen [Populus tremuloides], Prickly Ash [Zanthoxylum americanum], White Ash, White Pine [Pinus strobus], and Choke Cherry [Prunus virginiana]) (Robinson, personal communication, 2012; White, 2008). Most of the ground flora is typical of past agriculture on the land, dominated by Kentucky Blue Grass (Poa pratensis), Timothy (Phleum pratense), Awnless Brome Grass (Bromus inermis), Wild Carrot (Daucus carota) and Canada Goldenrod (Solidago canadensis) (White, 2008).

2.1.4 Managed Lawn

Land cover at the NWA entrance on Drummond Concession 9A around the parking lot and boat launch is grassed lawn, dominated by Kentucky Blue Grass (Poa pratensis), White Clover (Trifolium repens) and Common Plantain (Plantago major) (White, 2008).

2.2 Wildlife

2.2.1 Birds

For many years, McEwen Bay has been known for its use by large numbers of waterfowl. The marshes provide important staging habitat for significant numbers of several different species of waterfowl during migration. The designation of the NWA and MBS provides birds with a safe haven from hunters and recreational boating as they migrate south each fall. Up to 10000 ducks can pass through the NWA in a day during fall migration, with American Black Duck (Anas rubripes), Blue-winged Teal (Anas discors), Green-winged Teal (Anas crecca) Hooded Merganser (Lophodytes cucullatus), Mallard (Anas platyrhynchos), Wood Duck (Aix sponsa), and Ring-necked Duck (Aythya collaris) being the most common (Lévesque, 1986; Rosien et al., 2004). Waterfowl species reported breeding in the NWA include Mallard, American Black Duck, Wood Duck, Blue-winged Teal and Canada Goose (Branta Canadensis) (EC-CWS, 2012a; Hamill, 2009; Hamill and Thomson, 2012; Rosien et al., 2004).

Several species of marsh dependent waterbirds have been recorded in the NWA, including American Bittern (Botaurus lentiginosus), Virginia Rail (Rallus limicola), Swamp Sparrow (Melospiza georgiana), Sora (Porzana carolina) and the federally threatened Least Bittern (Ixobrychus exilis) (EC-CWS, 2012a; Hamill, 2009). Waterbird species reported breeding in the NWA include the Common Loon (Gavia immer), Marsh Wren (Cistothorus palustrisi), Virginia Rail, Black Tern (Chilidonias niger), Pied-billed Grebe (Podilymbus podiceps) and Common Tern (Sterna hirundo) (Figure 7; EC-CWS, 2012a; Hamill, 2009; Hamill and Thomson, 2012).

There is limited information on landbird species and use of upland habitats within the NWA. However, recent bird surveys reported over 50 species of landbirds using a variety of habitats (i.e., upland forest, old field, meadow and wetland) (Hamill, 2009; Hamill and Thomson, 2012). Landbird species reported include warblers (For example, Yellow-rumped Warbler [Dendroica coronata] and threateded Canada Warbler [Cardellina canadensis], thrushes (For example Wood Thrush [Hylocichla mustelina]), sparrows (For example Swamp Sparrow [Melospiza georgiana] and raptors (For example Osprey [Pandion haliaetus]) (Hamill, 2009; Hamill and Thomson, 2012). The majority of landbird species reported are migratory species and will use the NWA as stopover and possibly breeding habitat. Landbird species confirmed breeding in the NWA include the Northern Rough-winged Swallow (Stelgidopteryx serripennis), the Belted Kingfisher (Megaceryle alcyon), Hairy Woodpecker (Picoides villosus), Rose-breasted Grosbeak (Pheucticus ludovicianus) and the Eastern Kingbird (Tyrannus tyrannus) (Hamill, 2009; Hamill and Thomson, 2012).

2.2.2 Mammals

Mississippi Lake NWA is also home to a variety of mammals. A small mammal trapping study documented five species residing in the NWA: Short-tailed Shrew (Blarina brevicauda), Masked Shrew (Sorex cinereus), Meadow Vole (Microtus pennsylvanicus), Deer Mouse (Peromyscus maniculatus) and the Eastern Chipmunk (Tamias striatus) (EC-CWS, 1980). The marsh provides habitat for several species of fur bearers including North American Beaver, River Otter (Lutra canadensis) and Muskrat (Hamill and Thomson, 2012). Black Bear (Ursus americanus), Red Squirrel (Tamiasciurus hudsonicus), Raccoon (Procyon lotor), White-tailed Deer (Odocoileus viginianus), Eastern Cottontail (Sylvilagus floridanus), Snowshoe Hare (Lepus americanus) and Porcupine (Erethizon dorsatum) can also be found within the NWA (EC-CWS, 2012b; Hamill and Thomson, 2012; Robinson, personal communication, 2012).

2.2.3 Reptiles and amphibians

Fourteen species of reptiles and amphibians have been reported in the NWA, including seven species of frogs and toads (For example, Green Frog [Rana clamitans], Tetraploid Gray Tree Frog [Hyla versicolor], American Bullfrog [Rana catesbeiana], Northern Leopard Frog [Rana pipiens], Wood Frog [Rana sylvatica], Northern Spring Peeper [Pseudacris crucifer crucifer] and Eastern American Toad [Bufo americanus americanus]), two snakes (Eastern Garter Snake [Thamnophis sirtalis sirtalis] and Northern Water Snake [Nerodia sipedon sipedon]),three turtle species (Midland Painted Turtle [Chrysemys picta marginata], Eastern Musk Turtle, also known as Stinkpot [Sternotherus odoratus] and Snapping Turtle [Chelydra serpentine] and one salamander (Northern Redback Salamander [Plethodon cinereus]) (Burns, 2003; EC-CWS, 2012c; Hamill, 2009; Hamill and Thomson, 2012).

McEwen Bay is identified as important habitat for American Bullfrogs, and studies reported an abundant population (Burns, 2003; Seburn and Hamill, 2000). However, bullfrog surveys in 2001 and 2003 suggest a decline in American Bullfrogs. In 2003, the population could not be estimated due to a small sample size (Burns, 2003). The American Bullfrog population has not been formally surveyed since 2003 due to poor habitat suitability (Burns, 2003); however, the species was found within the NWA in 2008, 2009 and 2012 (Hamill, 2009; Hamill and Thomson, 2012).

2.2.4 Fish

There is no data specific to the NWA. However, Mississippi Lake is a popular site for sport fishers, supporting both warm and coldwater fish species (Kerr, 1999). Nineteen species were recorded in Mississippi Lake in 2009, with Yellow Perch (Perca flavescens) being the most abundant, followed by Pumpkinseed (Lepomis gibbosus), Smallmouth Bass (Micropterus dolomieu), Bluegill (Lepomis macrochirus), Northern Pike (Esox lucius), Rock Bass (Ambloplites rupestris), Log Perch (Percina caprodes) and Walleye/Yellow Pickerel (Sander vitreus) (OMNR, 2009). McIntyre Creek passing through the southeast end of the NWA provides spawning areas for Walleye, Northern Pike and Largemouth Bass (Micropterus salmoides)(Kerr, 1999).

Walleye, Largemouth Bass and Black Crappie (Pomoxis nigromaculatus) are all introduced species in Mississippi Lake (Kerr, 1999). In the past, Mississippi Lake has been stocked with Smallmouth Bass, Walleye, Lake Trout (Salvelinus namaycush) and Lake Whitefish (Coregonus clupeaformis) (Kerr, 1999). Fish stocking was discontinued in 1980, and the lake is managed by OMNR as a self-sustaining fishery (Kerr, 1999).

2.2.5 Invertebrates

Although there are no inventories or surveys of invertebrates, it is likely the NWA supports a variety of invertebrates. The wetlands produce numerous flying insects, which insectivorous bird species consume to fuel their spring and fall migrations (EC-CWS, 2012a; Hamill, 2009; Hamill and Thomson, 2012). Field visits and surveys have reported several species of dragonflies, damselflies and butterflies (Hamill and Thomson, 2012; White, 2008).

The Monarch butterfly (Danaus plexippus), listed as special concern (SARA), has been reported at the NWA (Hamill, 2009). Monarchs use the NWA as migratory and stopover habitat during late summer and early fall, stopping to feed on plants or roost in trees on their way south to their wintering grounds Committee on the Status of Endangered Wildlife in Canada (COSEWIC), 2010; Government of Canada, 2012; Hamill, 2009).

2.2.6 Species at Risk

Ten species at risk, listed under the federal Species at Risk Act (SARA), have been reported at Mississippi Lake NWA, including the endangered Butternut, threatened Eastern Musk Turtle, Canada Warbler, Golden-winged Warbler (Vermivora chrysoptera), Least Bittern and special concern Broad Beech Fern (Phegopteris hexagonoptera), Monarch butterfly, Snapping Turtle, Red-shouldered Hawk (Buteo lineatus) and Rusty Blackbird (Euphagus carolinus) (Table 3; Committee on the Status of Endangered Wildlife in Canada (COSEWIC), 2013; Government of Canada, 2013; Hamill, 2009; Hamill and Thomson, 2012).

In addition, the Barn Swallow (Hirundo rustica), Bobolink (Dolichonyx oryzivorus), Eastern Meadowlark (Sturnella magna) and Wood Thrush, assessed and designated as threatened, and Eastern Wood-pewee (Contopus virens), assessed and designated as special concern by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC), have been observed at the NWA (Table 3; COSEWIC, 2013; EC-CWS, 2012e; Hamill, 2009; Hamill and Thomson, 2012). The Bald Eagle (Haliaeetus leucocephalus) and Black Tern are provincial species at risk classified as special concern under the Ontario Endangered Species Act, 2007 and have been reported at this site (Table 3; Government of Ontario, 2012; Hamill, 2009; Hamill and Thomson, 2012; White, 2008).

It is anticipated that critical habitat^Footnote1 may be identified on the NWA for a number of species at risk.

The majority of the endangered Butternut within the NWA have been infected by the fungal blight (i.e., Butternut canker [Ophiognomonia clavigignenti-juglandacearum]) and are in decline (Hamill and Thomson, 2012; White, 2008; Wilson, 2009).

For more information on the federal SARA,COSEWIC and the provincial Endangered Species Act, 2007, refer to Appendix 1 or visit:

• Species at Risk Public Registry
• Committee on the Status of Endangered Wildlife in Canada
• Endangered Species Act

^a SARA (Species at Risk Act): Extinct, Extirpated, Endangered, Threatened, Special Concern, Not at risk (assessed and deemed not at risk of extinction) or no status (not rated).

^b COSEWIC (Committee on the Status of Endangered Wildlife in Canada): Extinct, Extirpated, Endangered, Threatened, Special Concern, not at risk (assessed not at risk) or data deficient (available information is insufficient to resolve eligibility for assessment or permit an assessment of the wildlife species' risk of extinction).

^c ESA, 2007 (Endangered Species Act, 2007): Ontario Ministry of Natural Resources (Species at Risk in Ontario [SARO] List): Extirpated, Endangered, Threatened, Special Concern or not classified.