Literature Review: Carefully Assessing Hazards

by Carl Strang

The Internet is a tremendous resource, providing ready access to all kinds of information. It also has become the foundation for significant social networking. Those two benefits have their dark side, however, as rumors and half-baked ideas spread readily and take on a semblance of fact. These might be amusing, except that they can take a nasty political turn, as in the attack on the American president’s legitimate citizenship, or unsupported fears regarding vaccines or genetically modified crop plants. Concerns about the measured declines in pollinator insects have drawn a lot of attention, and a wide range of hypotheses. This is good, as science works from hypotheses. The next step is to test these, but as is the case for the speculations listed above, lots of people want to jump directly from possibility to voting decisions or legislation without waiting for the results to come in. This week’s selected study from the 2013 scientific literature is an example of how possibilities need to be tested and sorted out. The results are not simple and straightforward the way Internet fear- and rumor-mongers would have it. The study focused on certain insecticides, white clover and our most common species of bumble bee.

Bombus impatiens worker. This is practically the only species of bumble bee we see in the Chicago area from August on.

Bombus impatiens worker. This is practically the only species of bumble bee we see in the Chicago area from August on.

White clover flower. This introduced legume has flowers strongly attractive to bees.

White clover flower. This introduced legume has flowers strongly attractive to bees.

Larson JL, Redmond CT, Potter DA (2013) Assessing Insecticide Hazard to Bumble Bees Foraging on Flowering Weeds in Treated Lawns. PLoS ONE 8(6): e66375. doi:10.1371/journal.pone.0066375

They looked at Bombus impatiens colony responses to lawns with white clover that were treated with two different lawn insecticides. Neither insecticide affected the bees if flowers present at spraying time were mowed from the plants. One of the insecticides (chlorantraniliprole) did not affect the bees, the other (chlothianidin, a neonicotinoid) affected bees that visited flowers that had been sprayed. New flowers opening after spray application did not affect bees.

Ecological interactions are complex. Biochemistry is complex. We humans have developed tools that help us deal with such complexity. Reason and intuition are two such tools, but when addressing real world problems involving physical entities or processes the formalized use of reason (i.e., science) is needed if we are to have clear and unambiguous answers. The fear-mongers manipulate peoples’ intuition to shape statements that sound right, but without the tedious sorting out of hypotheses through scientific studies such fearsome forecasts have to be regarded as nothing more than possibilities.

Beautiful Weeds

by Carl Strang

I have fallen way behind in reporting on new wildflowers at Mayslake, which I am tracking to begin phenology  records for that preserve. Today I want to feature weeds. This is a term I use with care, as it has several distinctly different meanings. In everyday use a weed is simply an undesirable plant. To a restoration specialist they are not native to the local landscape. If they are good competitors, a special effort is needed to remove them. If not, they simply will be pushed aside by native plants as the latter get established. To an ecologist, “weedy” organisms can be plants or animals, and are defined by their life history strategy. In comparison to other organisms they have short lives, grow quickly in disturbed habitats where there is little competition (weeds are poor competitors), and produce large numbers of small seeds or young that can disperse widely. One or more of these definitions apply to the plants I am sharing today, and I am trying to use photos that reveal their beauty . So, let’s begin with dame’s rocket.

Dame's rocket b

I have found it in only one corner of the preserve, near the friary, but as you can see it is abundant in that spot. In the cracked pavement around the friary I found this field bindweed.

Field bindweed 2b

Its flowers place it in the morning glory family. One of the friary’s abandoned gardens has some horse radish growing, and that patch may be the source of a few plants growing more than 100 yards away, near the parking lot for the off-leash dog area.

Horse radish 1b

Other weedy plants can be found in lawns around the main parking lots and mansion. They include white clover,

White clover 2b

black medick,

Black medick b

and mouse-ear chickweed.

Mouse-ear chickweed 2b

Amur honeysuckle is a bane of our woodlands, but it has a beautiful floral display this time of year.

Amur honeysuckle b

I admit to confusion in the white flowering members of the genera Silene and Lychnis, but believe I have the identification correct for this white campion, or evening lychnis, L. alba.

White campion b

Common wood sorrel is regarded as native, but it certainly has a weedy life history strategy.

Common wood sorrel 1b

Finally there is the Indian strawberry, named for its origin in south Asia and the small red fruits that resemble strawberries but are inedible.

Indian strawberry b

The leaves also bear a resemblance to our native wild strawberry, but the yellow flowers are a giveaway.

A final note is to thank Scott N. again for his assistance, this time with the field cress. Once that former mystery plant started elongating its fruiting stalk it became, to my eye, less beautiful and mysterious, but much more recognizable.

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