The SeaDoc Society and YMCA Camp Orkila present “This was a good idea? Unintended consequences of well meaning actions,” a lecture by Peter Arcese of the University of British Columbia. It will be on Tuesday, Oct. 9, 7 p.m. at the Emmanuel Episcopal Parish Hall. The presentation is free as part of the Marine Science Lecture series.

Humans have created major ecosystem changes the San Juan Islands by introducing non-native species and by removing native species. For example, native black-tailed deer, now free of natural predators and rarely hunted, occur at densities over 10 times what would be
expected on islands with native predators. Consequently, deer shape the diversity of shrub, meadow plant and bird species in the region. They’ve even been responsible for the local extinction of iconic native plants that were once abundant.

These and other examples of rapid ecosystem change indicate that active stewardship and land management are needed to insure the persistence of many native and rare species.