Stinkpot (Sternotherus odoratus) COSEWIC assessment and status report: chapter 5
Habitat
The stinkpot is highly aquatic and can occupy any shallow water body with a slow current and soft substrate (Cook 1984). In Canada, stinkpots have been found in lakes, streams, marshes, ponds and rivers (e.g. Lindsay 1965; Brunton 1981; Chabot and St. Hilaire 1991; Edmonds and Brooks 1996; NHIC unpubl. data). Stinkpots prefer shallow water and are rarely found at depths greater than 2 m (Mahmoud 1969; Edmonds 1998). In Oklahoma, the dominant vegetation where stinkpots were found consisted of Chara and Myriophyllum (Mahmoud 1969). In a Parry Sound, Ontario, population, stinkpots were found in association with a variety of vegetation, including grasses (Poaceae), sedges (Cyperaceae), rushes (Juncaceae), cattails (Typha sp.), pipewort (Eriocaulon sp.), water shield (Brasenia sp.), hornwort (Ceratophyllum sp.), Elodea (Elodea sp.), bullhead lilies (Nuphar variegatum), fragrant lilies (Nymphaea odorata), pickerel weed (Pontederia cordata), pondweed (Potamogeton sp.), arrowhead (Sagittaria sp.), bladderwort (Utricularia sp.), and water celery (Vallisneria sp.) (Edmonds 1998). In Quebec, stinkpots were found in association with Elodea canadensis, Hydrocharis morsus-ranae, Sagittaria lanifolia, Nymphaea odorata and Potamogeton ephydrus (Chabot and St. Hilaire 1991). Stinkpots require a soft substrate within which to bury during hibernation (Ernst et al. 1994).
Stinkpots usually do not venture onto land except when females lay their eggs. Nesting habitat is considerably variable. Some females lay eggs on the open ground, whereas other females dig well-formed nests up to 10 cm in depth. Most nests are shallow excavations in decaying vegetable matter, leaf mold, rotting wood (such as under stumps or fallen logs), or muskrat lodges (Ernst et al. 1994). In Point Pelee National Park, stinkpot eggs were found in a muskrat lodge, and at Mellon Lake, 12 eggs were found in a hollow rotting log that formed part of a dock (NHIC unpubl. data.). In two populations on the Precambrian Shield, stinkpot nests were in shallow gravel or soil-filled rock crevices close to the shoreline (Lindsay 1965; Edmonds and Brooks unpubl. data). These crevices were located on rock faces exposed to direct sunlight. It is probable that such atypical nesting habitat was selected because most decaying vegetable matter in this geographic region (Precambrian Shield) is not exposed to direct sunlight. Direct sunlight may be necessary at northern latitudes to maintain a sufficiently high incubation temperature for complete embryo development (Bobyn and Brooks 1994). Hence, suitably warm nest sites may be limiting for the stinkpot in central and eastern Ontario.
Suitable stinkpot habitat is abundant across south-central Ontario, especially in the Canadian Shield Region. However, urbanization continues to encroach on many wetlands in Ontario, primarily close to Lake Ontario and Lake Erie, where some stinkpot populations are (were) located. As well, shoreline development for cottages and recreational activity is destroying suitable habitat in the Precambrian Shield areas occupied by stinkpots.
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