Supporting pollinators brings many benefits
For the sake of pollinator species, Susan Carpenter changed her view during her 12 years of managing the four-acre native plants garden at the University of Wisconsin Arboretum in Madison, a facility that covers 1,100 acres.
Carpenter, who is the senior outreach specialist for the Arboretum, was a presenter at the 20th annual 'Toward Harmony with Nature' conference sponsored by the Fox Valley area chapter of Wild Ones. The Arboretum garden she oversees was developed from 1997 to 2002 by landscape designer Darrel Morrison, who was the keynote speaker at the conference.
During a one-hour trek in the Arboretum's restored native plant garden, Carpenter was able to identify eight native bumblebee species, six butterfly species, two moth species, flies, beetles and honeybees. The Arboretum also has expanses of savanna, woodland, wetland and prairie.
Being bee friendly
Carpenter devoted most of her presentation to how to be friendly to bees — both the remaining portion of the more than 400 bumblebee species that were native to Wisconsin and the imported European honeybees, which are essential to the pollination of such Wisconsin crops as apples, cranberries, cherries, peas, cucumbers, pumpkins and squash.
Other pollinators include birds, wasps, flies, moths and beetles, Carpenter said. Their efforts are beneficial to about 85 percent of the plant species, particularly for full fruit and seed development.
Of the approximately 25 bumblebee species surviving in Wisconsin, most are solitary bees, which means that they do not gather in colonies or hives, Carpenter explained. Unlike honeybees, they are also only annual species who have a mated queen survive somewhere on the landscape during the winter in most cases.
Carpenter is pleased that possibly 12 of those bumblebee species have been seen at Arboretum and that the identity of 10 of them has been confirmed. She pointed out that three of them are on the threatened species list.
Rusty patched bumblebee
A particular concern exists with the rusty patched bumblebee, which is rarely seen at the Arboretum, has lost 87 percent of its previous habitat, and is surviving in small numbers in Wisconsin, northern Illinois and eastern Minnesota, Carpenter reposaidrted. This species has a mated queen that nests at a depth of more than one foot in the ground and emerges in synch with the first flowering plants in the spring.
Although dandelions and creeping Charlie do not enjoy a good reputation, they, along with Dutchman's breeches, serviceberries, cherries and lawn clovers, are among the flowering plants that the rusty patched bumblebee depends on the spring, Carpenter said. For later in the season, it likes the long tubed flower of the phlox plant for collecting pollen or nectar,.
Depending on the species, bees have their own natural cycle, Carpenter noted. One of them relies on willow tree blossoms and completes its cycle in only three weeks, while the cuckoo bumblebee is a parasite, which similar to the cowbird, lays eggs in the nests of other species.
To prepare for the winter, bees need to have a succession of flowers that are available well into the autumn, Carpenter said. She has asters, coneflowers and goldenrod on that list.
When in doubt, check which plants bees are visiting, Carpenter advised. Take pictures, keep records, don't buy any pretreated nursery plants, don't apply any pesticides or herbicides (even systemic ones), refer to the 'Pollinators of Native Plants' book by Heather Holm and be an advocate for such practices, she suggested.
Leave some mess
Another good way to support bee populations is to 'leave a little mess' on the landscape so the solitary native bees can find habitat for the winter, Carpenter said. Candidates for that include leaf litter, garden plant debris, dried hollow plant stems, rocks, decaying or hollow logs and the bare soil in which some bee species find a hole for winter habitat, she said.
Not much is known about the winter nesting habits, Carpenter observed. She said they could be in grass, in ditches or in holes made by squirrels or other animals.
Even with care by their owners, honeybees are suffering 30 to 60 percent losses during the winter, Carpenter noted. She cited loss of habitat, pests, diseases, weather, climate change, the interaction of those challenges and the presence of large tracts of monoculture crops on the landscape as being responsible for that trend.
Carpenter, who has searched for bees at 60 sites in southern Wisconsin, also recommends such references as www.bumblewatch.org, the Xerces Society, and www.bugguide.net.