ARBORETUM NEWS (NATURALISTSNOTES)

Prairies in Bloom – Adapted to Drought

SUNDAY, JULY 8, 2012

Alvin, Simon, and Theodore … remember them? Cute, high pitched, Grammy Award winning singing chipmunks. For me, their musical stylings are best in small doses. That’s the same way I feel about their real life ancestors, Tamias striatus, the eastern chipmunk. Often the first notes I hear in the woods are the various chipmunk chirps, chips, chucks or churrs. Usually what sounds like a chuck or churr is more resonant, sounding like it came from deep in the throat – and lower in tone and volume than the excited, loud and high-pitched chips. Today we heard this calmer echoing, lower toned chuck, chuck, chuck from the pine woods of the Grady Tract. Earlier in the morning, I heard the very high pitched blasting alarm note or two, followed by loud repeated chirps from several chipmunks as I passed by. There are short periods of a few days to a week when I hear them chipping persistently, but for much of the year I hear them more sporadically. Like many common birds and their calls, the chipmunk is an animal that has several vocalizations very familiar to us – but the details of what it all means can be a little more elusive.

Most research I have read indicates that much of the chirping is done by the adult female aimed at scolding the kids and her mate, “get out of my territory – it’s time to set up your own place!” With two broods each year, this would account for the sporadic and intense periods of chipping. Both the adult male and female and young ones will also chip when they sense danger. Most likely the sudden, loud, high pitch chips followed by more chipping and the sound of scurrying feet and a flash of Alvin and a forest neighbor or two disappearing down into their well-known burrows was their signal and behavior to my approach. For most of their adult life, except for mating, chipmunks set up their own territory with an underground burrow (complete with a storage area for up to eight pounds of seeds). There is a small entry hole and an exit or two. I have become well acquainted with these as I am getting better at avoiding stepping into several of them in my yard to avoid twisting my feet and ankles. These burrows are set up inside a territory of about a half to three quarters of an acre. My question about this is how come on my ¾ of an acre do I seem to have an endless supply of them outside my bedroom window? Did they see me cart their mom off and move in? Hard to say. The area that they defend can be much less than the entire gathering territory – if food sources are abundant they may tolerate another chipmunk and their burrow as close as 50 yards or so.

What caught our eye next was the extensive patch of pokeweed on our way to the Grady Knoll. American Pokeweed (Phytolacca americana) is usually about six feet at maturity. It has a large taproot and thick, semi-succulent stems. Drooping from the ends of the stem or raceme are a line of small white and green flowers, which will soon become bright red with dark purple juicy berries. Although pokeweed is toxic to most mammals, including us humans – we have used it as an anti-viral and as a tonic for many other ailments and have also used the berries and the leaves as food -after a prescribed regiment of boiling. The pokeweeds in the Grady Tract had formed such a thick patch, I first suspected they may have underground rhizomes and were spreading vegetatively. But, they don’t – pokeweeds spread by seed. They have a fair amount of seeds – but nothing compared to some of our mustard species. They succeed in dominating a landscape by attracting lots of birds to eat the berries and then spread their seeds. This is followed by a very high rate of germination (80% or more from one study). The seedlings will grow large oblong leaves and shade out much of the possible competition.

In my prairie garden, Bee Balm or Wild Bergamot (Monarda fistulosa) can be fairly aggressive in its spreading abilities. Along the trails up towards and on the Grady Knolls, the Monarda dots the landscape with its rays of tubular pale purple flowers in very small patches, reminding us that it is there. We will have to watch over the years to see how well it will compete and spread on the edges of the Grady Knoll. As we walked up on the knoll there were the skirted rings of flowers of purple prairie clover (Dalea purpurea), and the small densely packed flowers of lead plant (Amorpha canescens). From a distance the lead plant flowers look like a spike of bluish gray flowers – but up close you can see that the gray is a hairy covering at the base of brilliant bluish purple tubular flowers with bright red and yellow stamens. The next flower we came upon that is more readily brilliant to our casual look was Butterfly milkweed (Aesclepias tuberosa). There were many more bees, moths, flies, and beetles than I could count or identify on the bright orange flowers. No butterflies though. We spotted some in the bushes a little farther down the trail.

Along the trail leading in to Greene Prairie, the small tubular flowers of Heal-all (Prunella vulgaris) and the Sensitive ferns (Onoclea sensibilis) seem to be doing well in the remaining patches of moisture I have seen around here. We noticed some other plant that may have found some precious moisture. Although, the deep rooted prairie plants seem to be doing okay in this drought – we did notice that the Rough Blazing-star (Liatris aspera) out in the sunny dry areas of the prairie were yet to bloom. However, by the east end of the prairie in the shade of some large oaks and smaller willows was an open patch of prairie that possibly offered enough moisture for the blazing stars there to jump ahead of the others to attract us and several butterflies to their bristly, bright pale purple blooms.

Out in the open prairie we saw Compass plants (Silphium laciniatum), Lead plant (Amorpha canescens), much more Reed canary grass than I would ever want to see, Illinois tick trefoil (Desmodium illinoense), Phlox (Phlox glaberrimia), lots of Mountain mint (Pycnanthemum virginianum), and Culver’s root (Veronicastrum virginicum) in bloom. You can also see some impressive ant mounds along the prairie trails. For blooming plants this crackling dry summer, the prairies will be your best bet.

Paul Borowsky
Naturalist

Located between Lake Wingra and the West Beltline Highway at 1207 Seminole Highway, the University of Wisconsin-Madison Arboretum features the restored prairies, forests and wetlands of pre-settlement Wisconsin. This 1,260-acre arboretum also houses flowering trees, shrubs and a world-famous lilac collection. Educational tours for groups and the general public, science and nature-based classes for all ages and abilities, and a wide variety of volunteer opportunities for groups, families and individuals are available.