Halkett Boat to Halkett Collection

For the last several years I have been studying the pollination ecology in Birds Hill Provincial Park focusing specifically on the rare Western Silvery Aster (Symphyotrichum sericeum) plant. I discovered that this species is self-incompatible (meaning it can’t fertilize its own eggs), and visited by a wide range of insect pollinators, including both flies and bees.

I also discovered that although this rare plant competes for pollinators with the much more common Showy Goldenrod (Solidago nemoralis) plant, a negative effect on seed production only occurs when their blooming periods overlap.

My first thought was that reducing the number of Showy Goldenrod plants in the community would result in more insect visitations for the rare plant but then I reconsidered as this did not intuitively seem like the right course of action. I wondered if removing plants would actually end up reducing the local insect population by reducing the quantity of nectar available. Perhaps the plants aren’t really competing at all but rather working together to support their mutual pollinators throughout the year. I also considered that any plant species that completes its flowering before Western Silvery Aster begins blooming would not be competing with it for pollinators at all. In fact, you could argue that the common plants facilitate insect visitation to the rare plant by providing nectar to their shared pollinators. Purple Prairie Clover provides nectar to Western Silvery Aster’s pollinators in July.

I decided to test this hypothesis by recording the insect visitors to other plant species before Western Silvery Aster even begins to flower. So far I have obtained some interesting results. One of the most important insect visitor species, a bumblebee (Bombus bifarius), was observed visiting five species of plants in June and July in addition to Western Silvery Aster. A second species, a bee fly (Anastoechus barbatus), was observed as early as July 12, pollinating three other plant species. It appears that when plants share pollinators, staggered flowering helps to (a) decrease competition, and (b) sustain pollinating insects throughout their active season.

I think that there is a tendency for western scientists to place too much emphasize on competition when interpreting the results of their research. We need to remember that co-operation, if it results in both species increasing their offspring, is also a beneficial strategy for survival.

For the last two years I have been searching for four species of rare Bugseed (Corispermum spp.) plants. Historically these plants were found in sand dunes and along the beaches of Lakes Winnipeg and Manitoba. Unfortunately there were very few recently collected specimens; most had been collected over 40 years ago. Attempts to determine the rarity status of these plants were hampered due to this lack of information.

During my field work I relocated fewer than half of the historical populations of Bugseeds indicating a substantial loss of habitat. In some cases, dune stabilization appears to have resulted in the loss of habitat for these species, which grow in bare sand. Flooding along the Red River and on Lakes Manitoba and Winnipeg in 2010 and 2011 may have also caused the loss of habitat as several historical populations had been previously found on the beaches, dunes and sandbars along the south shore of these lakes. Balancing out the losses a bit was the discovery of seven new localities in the province including a very large population of Hairy Bugseed (C. villosum) in the sand dunes in Grand Beach Provincial Park.

Unfortunately, I could not locate any Pallas Bugseed (C. pallasii) at the three sites where it was historically found although I did find some American Bugseed (C. americanum) at two of the sites. Pallas Bugseed is still present in other Canadian provinces so it is not extirpated in the country. It is possible that this species spread into Manitoba from other provinces where it is native along railways and then subsequently disappeared as more hardy weeds took over the habitat. As the seeds of these species are quite long lived and tolerant of burial, Pallas Bugseed may still be here in the province, hiding in the soil and waiting for the right conditions to germinate.

Today I got to study a plant specimen that had been collected 100 years before I was born in 1872 by one of the most famous Canadian botanists, Dr. John Macoun. Dr. Macoun accompanied the engineer Sanford Fleming to look for a railroad route through the Canadian west and determine the area’s agricultural potential. Macoun collected thousands of plant and animal specimens on his journeys, which involved travelling either by horse or canoe. He collected over 100,000 plants in his lifetime including over 1,000 that were new to science. In total 48 new species were named after him, including Macoun’s buttercup (Ranunuculus macounii).

Touching Macoun’s handwritten label made me wonder what western Canada looked like back then. Just acres and acres of grasses and fragrant wildflowers, and thousands of birds, antelope and deer I imagine. Or maybe it just felt big and empty and utterly overwhelming.

I also mused about the end result of his journeys. Macoun’s report on the fertility of the prairies convinced Canada to send immigrant farmers to this land. How would he have felt knowing that his report paved the way for the almost complete destruction of the grassland that he had wandered on? That plants and animals that had once numbered in the billions would be reduced to mere handfuls less than a century after his arrival? Perhaps it would have made him happy, knowing that the land was settled with European farmers and ranchers. But I suspect that that happiness would be mingled with at least some regret that no one would ever again experience the wild west as he had.