The Royal Canadian Institute holds free public science lectures at the University of Toronto every Sunday afternoon in fall and winter. The lectures cover many different topics in science, and are aimed at a general audience. Today’s lecture was “The embarrassment of Riches: The Ecological Consequences of Increasing Numbers of Arctic Geese”, by Robert L. Jefferies. It was about the broad effects of geese migration.
He talked about geese migration patterns, and how agriculture can affect geese population half a continent away: Snow geese breed in the Hudson Bay lowlands and migrate south in winter. A shift in agricultural activities has over time led to an increase of farmland along the geese’s migration routes. The geese eat farmland crops to get much-needed nitrogen into their system. This used to be difficult for them, but the abundance of farmland has now made it easy for them to get their nutrients. On top of this, there are many protected wildlife areas along their route, which means that geese are being hunted less. As a result, more and more geese have been flying back north in the spring. This has in turn caused the Arctic lowlands to be completely overgrazed: all the vegetation is gone in several areas. This of course also affects other species that breed in these regions, and the complicated pattern of cause and effect makes it very difficult to manage conservation. Controlled hunting has brought the snow geese numbers back down a little bit in recent years, but replanting the vegetation has proved to be very difficult.
Here is a relevant publication (in pdf) on the goose story.
Last week’s Science on Sundays lecture was a talk about Avian Flu, by Donald Low, Toronto’s most famous microbiologist, who you have all seen on TV a few years ago during the SARS breakout. Dr. Low’s talk should be available on the Royal Canadian Institute website some time this week. Meanwhile, you can have a look at multimedia presentations of this past fall’s lectures on the site, as well as the schedule for the upcoming weeks. They’re all on there!