"Our work suggests that rock climbing has significant negative effects on all aspects of the snail community on cliffs," say Jeffery Nekola of the University of Wisconsin in Green Bay, and Michele McMillan and Douglas Larson of the University of Guelph in Canada in the April issue of Conservation Biology. This study builds on the researchers' previous work showing that rock climbing can decrease the diversity and abundance of plants and lichens on cliffs.
The Niagara Escarpment is a series of limestone cliffs that extends from Ontario, Canada, to Michigan, Wisconsin, Illinois and Iowa. Noted for having eastern white cedar trees that are nearly 1,000 years old, the Escarpment is also a hotspot of snail diversity, with about half of the 80-odd land snail species found in Ontario. Most of the snails found in the Escarpment are known as "minute" snails because they are less than a tenth of an inch across. They live inside soil and many graze on the algae that grows on the cliffs.
Nekola and his colleagues compared the diversity and abundance of snails in climbed and unclimbed cliffs along a two-mile section of the Niagara Escarpment near Milton, Ontario. They studied snail shells in soil collected from three parts of the cliffs: the top edge, the cliff face and the base. Altogether, the researchers found 40 species of snails and more than 14,000 intact shells.
The results showed that climbed cliffs had less snail diversity and abundance. Climbed cliffs had only half as many snail species (about 5 vs. 10 per cup of soil, respectively) and only about a fifth as many snails (roughly 15 vs. 78 per cup of soil, respectively) as u
Contact: Jeffery Nekola
Society for Conservation Biology