A snail that has been on the endangered species list since 2022 has been discovered at a nature preserve near Woodstock.
Upper Thames River Conservation Authority (UTRCA) Species at Risk Biologist Scott Gillingwater located live Shagreen snails at the Snake Woods Nature Preserve. The snails were first observed in April 2023 and corrected a year later via iNaturalist, a social network where users share biodiversity information to help each other learn about nature. The sighting was subsequently verified by two mollusk experts that specialize in Canadian snails, before a second specimen was observed on the property last month.
The Shagreen is a terrestrial medium-sized snail with a width of about one centimetre. It is yellow to brown coloured and has three tooth-like denticles in the opening of its shell. It's identifying feature is its closed umbilicus. That feature, which sets the Shagreen apart from other similar looking species, was noted by an iNaturalist user, which led Gillingwater to consult with a pair of malacologists to confirm the species.
"This is why iNaturalist is so important to scientists. Without access to international experts, this find may have fallen through the cracks,” said Gillingwater.
Until this discovery near Woodstock it was believed the snail could only be found on two Lake Erie islands - Pelee Island and Middle Island. When its population was thriving, the snail used to live in the Leamington-area and five Lake Erie islands.
"This suggests that Snake Woods Nature Preserve could be home to the last remaining mainland population in Canada," the conservation authority said in a statement.
The Shagreen has dwindled in numbers due to habitat loss and invasive species such as earthworms. Its survival has also been threatened by climate change related flooding and droughts on Pelee and Middle Islands and extreme temperatures.