A Monarch Caterpillar having lunch. This was taken in a roadside ditch in Minnehaha County, South Dakota, but it’s not nearly as common a sight as it could (should) be. Ditches here are mowed, sprayed, and otherwise managed, resulting in ditches (even on rarely used gravel roads) often looking like golf courses or urban lawns.
Yesterday I birded several locations to the northwest of Sioux Falls. I traveled through not only Minnehaha County (where Sioux Falls is), but also nearby McCook, Lake, Kingsbury, and Brookings counties. When I go birding around here, I typically travel on gravel roads, to minimize interaction with other cars and reach places where I can actually stop and watch for a while. While traveling gravel roads through these counties yesterday, I was struck by the incredibly variable management of roadside ditches.
What’s that? You don’t pay much attention to the ditches when you’re driving? I can’t say I normally do either, but I was recently at the North American Congress for Conservation Biology Conference (NACCB), where there were a number of presentations on the plight of the Monarch Butterfly. They’re a species dependent upon milkweed. One of the problems is that SO much of the United States landscape is now being used for agriculture, urban development, energy development, and other uses, and milkweed is crowded out. Even in areas adjacent or near to agricultural land, herbicides are often used for weed control, further reducing milkweed abundance.
This spring, I was contacted by researchers who were studying landscape change, and how it potentially impacted Monarch Butterflies. Specifically, they were interested in using our landscape modeling to look at future landscapes, and the resultant impacts on both milkweed and Monarch butterflies. In the model they used, they were assuming that roadside ditches in most areas were places where milkweed was likely to be found.
As I quickly learned on my drive yesterday, that characterization is clearly NOT true in many areas, and seems to be strongly driven by local politics, in terms of local land management. When driving in Minnehaha County, I often come across sprayer trucks, actively spraying herbicide in all the ditches to keep herbaceous weeds in check. I also often come across tractors with mowers attached, mowing the ditches close to the ground. Yes…even for the GRAVEL roads that rarely get traffic, the ditches are treated in this manner. The result? The ditches around here often look like a well-manicured lawn (see photos below). Hell, they often look BETTER than my yard does!! They often consists of nearly 100% brome grass (an exotic, BTW), while milkweed stems are few and far between, and are typically relegated to small spaces where a sprayer didn’t reach.
When driving through parts of Kingsbury and Brookings counties, I was struck by the incredible difference in the ditches. Many ditches clearly hadn’t been mowed in some time, if they were ever mowed. Grasses were mixed with wildflowers, other herbaceous plants, and yes…MILKWEED (see more photos below). Milkweed was often present in very high abundance. The issue clearly isn’t adjacency with actively growing agricultural crops. As the photos below show, the Brookings and Kingsbury County ditches often had an abundance of herbaceous plantlife in areas directly next to corn and soybean fields.
It is possible that I just happened to drive on some gravel roads yesterday in Kingsbury and Brookings counties where no action was taken, but spraying was occurring elsewhere. On the Brookings County website, for example, I was disappointed to find this page, that notes the county DOES spray right-of-ways with “products such as 2,4-D, Tordon 22K, and possibly mixtures of them“. They do note on their web page that they spray in May, so clearly they don’t spray all ditches, as the photo below (with the milkweed) is on a gravel road on the very western edge of Brookings County.
During the NACCB conference, one talk I heard focused on recovery efforts for the Monarch, and plans in place to improve Milkweed abundance and improvement. Even a dead-red, conservative state like Oklahoma is taking action, with the Oklahoma highway department specifically managing ditches for Monarch and pollinator habitat. They are specifically planting wildflowers and milkweed along highways in an effort to help not only Mmnarchs, but other species that depend on these plants. The discussion at the conference was a similar “Monarch Highway” stretching from Texas up northward through southern Canada, an area with highway ditches specifically devoted to herbaceous plants, including Milkweed.
Could such a thing happen up here in South Dakota? I’ll see it when I believe it. We have such an focus on agricultural production, that I find it hard to believe they’d accept any land management action that could possibly harm that production in any way. Not that I BELIEVE an aggressive, pro-Milkweed, pro-Monarch Butterfly agenda would harm agricultural production, but in this VERY red state, environmentalists are usually portrayed as the enemy. For a large portion of the populous here, I have no doubt they’d view a program like Oklahoma’s as an attempt by environmentalists to meddle in local affairs.
It’s hard to imagine now, but when we moved to South Dakota 25 years ago, our Congressional delegation was completely Democratic. Hell, we had Tom Daschle as a Democratic Senate Majority Leader. How times have changed. Serendipity may have led to the 3 Democratic Congressional delegates 25 years ago, but in today’s anti-environmentalist concerns for issues like the Monarch Butterfly as far removed from most South Dakotan’s minds.
I wish my yard looked this green, lush, and free of weeds. Driving home yesterday through northern Minnehaha County, THIS is what roadsides looked like. Even for lightly traveled gravel roads such as this one. Frequent spraying and mowing ensure a monoculture of brome grass, with nary a milkweed stem in sight.
In contrast to the Minnehaha County ditch, this is what I saw in many parts of Kingsbury and Brookings Counties. This ditch clearly hadn’t been mowed or sprayed this summer, and was full of herbaceous plants other than brome grass, including many milkweed stems.