Educational Media Reviews Online

This is an episode of David Suzuki's Canadian Broadcasting Corporation program The Nature of Things. It focuses on the North American grasslands, which two hundred years ago occupied most of the central part of North America and sustained a vast and complicated ecosystem. The basis of that ecosystem was native grasses, adapted to survive in a harsh environment of cold winters, hot summers and variable and scanty rainfall. Such grasses concentrated nutrients which many herbivores like prairie dogs, pronghorn antelope and most visibly bison depended upon. The existence of these grasseaters supported an array of predators such as wolves, bears, coyotes, foxes and burrowing owls. There also existed a complicated network of insects that sustained themselves on a limited assortment of plants; here, the plants got a return for their providing food by getting their seeds dispersed over wide areas.

This ecosystem was disrupted by the advent of European settlers in the eighteenth through twentieth centuries. The complex network of grasses was largely replaced by agricultural monoculture. When the abnormally wet period of the late 1800s was followed by drought in the 1930s, much of the land, unprotected by its original dryland grass cover, blew away and resulted in the Dustbowl. The Native American and Native Canadian cultures that depended on buffalo for food during the long, harsh winters of interior North America had their food supply and economies irreparably destroyed.

There is awareness in both Canada and the U.S. among many scientists and ranchers of the value of preserving what little grassland (estimated at about one-tenth of one percent of the original) remains. However, even that small fragment is endangered now by uncontrolled suburban real estate development, which hikes land prices beyond the ability of ranching agriculture to realize a profit. Many plant and animal species have become extinct because of habitat degradation, and imported European grasses have successfully pushed out many of the aboriginal forbs. Government and citizen attention to preserving what remains of a once magnificent and vibrant ecosystem is essential.

This film is visually arresting, and its scientific footing is supported by interviews with several American and Canadian ecologists throughout. Highly recommended for undergraduate university students with an interest in the life sciences.