We begin this episode 40 miles above the fertile fields of Alberta. From up here the rectilinear hashmarks of crop boundaries are pocked and dented by darker, irregular patterns, like raindrops pooling on a patio table. Those are pothole wetlands left behind by the scraping and gouging of the receding Wisconsin glaciation thousands of years ago. These days you’ll find these watery basins, often as many as 40 per square kilometre, all over the prairies in Canada and the U.S. But, when the glaciers receded their were many, many more of them, millions of them. They became an essential habitat for hundreds of plant, animal and insect species - especially at their margins. But in the last century humans have managed destroy a lot of those formerly abundant wetlands. In some places 70 per cent are already gone. Those that remain are often sometimes precariously surrounded by vast fields of canola, wheat or barley.
In previous podcasts we’ve talked about the importance of those wetlands to waterfowl, for flood and drought protection, as natural water filters and as environments that increase our general health and sense of well-being.
But, in this episode we’re going to explore another advantage of prairie potholes. To do that, we need to get a lot closer to the ground.
Down there, a few feet about the heart of a wetland we’re in insect territory. Thousands of species of bees, flies, spiders and beetles make their homes in hollows, holes and native grasses. And many of those insects are pollinators. Others are predators that could make a light lunch out of other insects that attack the crops that surround the wetland.
So, could the insects this wetland husbands be of service to the surrounding crops? In other words, could pollination and pest control be another advantage of keeping wetlands around?
To find out I talked with Paul Galpern, a Landscape ecologist at the University of Calgary.