Return to the Wild - Evolving perspectives on Canadian wildlife
Bees work busily on a hive.

You’re not from around here, are you?

Throughout the history of life on Earth, species have moved around as environmental opportunities beckoned or survival dictated. This process continues today, often disrupting the ecological balance of places we have come to value. Moreover, we often bring on such invasions, introducing a desired species that will combat some problem with another species on our home soil. Conversely, organisms can simply move into some neighbouring area when their home habitat becomes less attractive. Either way, stories involving the arrival of foreign species rarely end well for the locals.

Effects of foreign species on local species

The sea lamprey — literally a blood-sucking parasite — represents one of the most notorious scourges to hit the Great Lakes. Introduced by the building of the earliest canals in the 19th century, this invader can kill 10 to 20 kilograms of fish in its lifetime. As it spread throughout the lakes, the lamprey devastated fisheries that relied on local species. The problem continues to this day, with both sides of the border pumping millions of dollars a year into methods of sea lamprey control.

The sea lamprey heads a long list of environmental interlopers among Canadian wildlife. Others include the honeybee, the zebra mussel, and the mountain pine beetle. The first two have been imported: the honeybee by European settlers for honey farms, and the zebra mussel as an unintended hitchhiker on Great Lakes ships. The mountain pine beetle is actually native to British Columbia, but its deadly spread throughout forests in that province and beyond has led scientists to dub it the worst infestation in North American history.

The honeybee, for its part, has a better reputation. With a huge role in food production, its mysterious population drop over the past few decades has more than a few scientists and growers worried. Meanwhile, the zebra mussel is being tolerated, as various methods for controlling it — including ships clearing bilge water in mid-ocean — have not yielded impressive results. And as the mountain pine beetle works its way through western lodgepole pine stands, scientists are trying to learn from the remnants left in the tiny insect’s wake.

Species from our exhibit that are greatly affected by foreign species (keeping in mind that most organisms will feel some effects from an invader) include the eastern bluebird and the Pacific salmon. The bluebird was in big trouble by the 1950s, losing habitat to the aggressive house sparrows English settlers brought over as pets, until dedicated naturalists brought it back from the brink. The Pacific salmon’s habitat remains under pressure from many factors, including the logging industry, human encroachment, and escaped farm fish that compete for food or carry disease. In each case, when a local species is barely hanging on in the face of habitat loss, climate change, or urbanization, throwing a foreign species into the mix often sounds a death knell.

Canadian Geographic retrospective

Learning to live with zebra mussels

Geo-Watch section of the magazine
May/June 1992

The advancing spread of the zebra mussel through the Great Lakes was examined in “Learning to live with zebra mussels,” in the “Geo-watch” section of the May/June 1992 issue. At the time, some areas were recording the highest concentrations of the opportunistic mussels in the world.

Described in the article as opportunistic bivalves originally from the Black Sea, they were introduced to Lake Ontario and Lake Erie in the 1980s from the bilges of foreign freighters. They found conditions for growth ideal in Canada and their most recent moves have taken them into Lake Superior, the St. Lawrence River as far east as Québec, and to Lake Muskoka in the cottage country of southern Ontario.

The western end of Lake Erie is described in this article as a “carpet of zebra mussels” with up to 350,000 per square metre. The typical concentration in Europe is 5,000 per square metre. However, this population in Lake Erie is expected to thin out as the food supply reduced.

A federally funded study by University of Toronto scientists in 1991 evaluated the current preventive measures being used — mid-ocean exchanges of freshwater for saltwater in bilges to remove or kill organisms in ships bound for the seaway. The study found that even after ships complied with the voluntary rinse, 33 percent still carried organisms that could live in the Great Lakes.

The few ways to destroy the mussels include ultraviolet rays, chemicals and pathogens. However, none of these are safe and/or efficient thus the author concludes that we will just have to learn to live with them.

Terms of endangerment

Don Gayton
May/June 1997

With impressive photographs — both colour and sepia-toned — and maps galore, author Don Gayton main argument is that saving species begins with saving space for them.

Starting off with the sad legacy of the now-extinct passenger pigeon, Gayton intones ominously that it wasn’t the first extinction experience on Earth, nor would it be the last. However, he notes more hopefully, the descendents of those responsible for the bird’s extinction went to great lengths to save the obscure, economically useless and slightly comical-looking burrowing owl.

From these two opposite cases, Gayton identifies that our instinctive attitude toward other species seems to range from indifference to antipathy. He notes that economists tell us that the marketplace can assign a correct utilitarian value to every species. However, he says that fortunately we are beginning to assign non-market, social values to species that may not score high economically speaking.

Dissecting the endangered species movement, he points out obvious flaws such as the reliance on fund-raising. Such a reality often depends on the cute and cuddly factor possessed by the species at risk. A huge blind spot he puts his finger on is the lack of awareness on our part when it comes to the threat posed by introduced species. Citing zebra mussels as a notorious example, he stresses that virtually every region of the country has an introduced plant, insect, marine invertebrate, fish, bird or small mammal actively displacing a rare or endangered species.

In the end he concludes that best of the endangered species movement includes the following: individual citizen involvement, the collection of basic biological data, support from diverse sectors of society, and emphasis on habitat rather than species.

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