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Evolution in the blink of an eye…

Prairie Deer Mouse - Peromyscus maniculatus bairdii

The cool thing about science and nature is that interesting stories are all around us. The tiny Deer Mouse, shown here, has overcome long odds, with the vast majority of its historical habitat gone. However, through some remarkable, fast-track evolutionary adaptation, they’re now able to cope with their new world. Photo by Gregory Smith.

It’s been a busy last week, without any time for birding or photography.  Or blogging, for that matter. I was down in Nebraska for a few days, mixing work and pleasure. The “pleasure” part was my fantasy baseball draft in Omaha Saturday.  Our fantasy league is likely one of the longest running leagues in the country, going back to 1985 during our freshman year in college, when fantasy baseball was still very new.  What’s great about it is that many of the original league members are still participating! It’s great fun, not only the draft itself, but catching up with old college friends.

The “work” part of my Nebraska trip was participation in the 2017 Great Plains Symposium, on the campus of the University of Nebraska-Lincoln. Much like the baseball draft, the symposium too was like stepping back in time, as I reconnected with some of my old college professors who were participating in the symposium. The focus of the symposium was “Flat Places, Deep Identities: Mapping Nebraska and the Great Plains”.  I gave a talk one some of the work I’ve been doing, mapping past, present, and potential future landscapes in the Great Plains.  It was a great symposium, a little different kind of crowd than I’m used to.  Given the work I do, most of the conferences and symposiums I attend deal with the physical sciences. This conference melded mapping, history, socioeconomics, and other social sciences that I’m not exposed to as much.  It was quite fascinating, particularly hearing about the history of Nebraska, using maps to help tell the “story” of change over time.

As part of the symposium “goodies”, participants were given a copy of The New Territory, a quarterly magazine that focuses on Missouri, Arkansas, Kansas, Nebraska, and Oklahoma.  I admit I’d never heard of the publication before. The content fits quite well with the focus of the symposium itself, with many human interest stories about the geography and people of the region. As a physical scientist, one piece caught my eye though. entitled “Evolution in the Cornbelt“, by Conor Gearin. The story focuses on the Prairie Deer Mouse (Peromyscus maniculatus bairdii), a common little fellow from the Great Plains that feeds on the tiny seeds of grasses and weeds in the prairies.

Researchers at Iowa State and Purdue University were curious how a species so adapted to life in the Great Plains has been able to thrive, given that >99% of the original tallgrass prairie in the region has been plowed under, converted to agriculture, urban land, or other man-made land uses. The grass and weed seeds the Prairie Deer Mouse had historically fed on were much more sparsely distributed than they were 200 years ago, yet the species is still quite common.  They started field work to assess the distribution of the nice, including setting up artificial nest boxes that the mice could use for habitation and food storage.  The results astounded the scientists.

Prior to beginning the work, it was assumed that deer mice populations would be the highest in “edge” habitat, areas such as grassy ditches, fencelines, or other “boundary” conditions where remnants of their traditional food sources may still be found.  However, they quickly found that the highest populations of deer mice were often right in the middle of very large corn and soybean fields, far from any traditional food source.  Clearly, Prairie Deer Mice had adapted to an agricultural setting, and were feeding on man-raised grains and pulses. The question was, how could a tiny mouse that was so well adapted to eating tiny grass and weed seeds shift gears and start feeding on corn and soybeans?

The researchers found historical deer mice in historical museums, creatures that had been preserved with taxidermy. Anatomical comparisons with Prairie Deer Mice from today found some stark differences.  The older specimens were well adapted to feeding on tiny seeds, with small mandibles and jaws that didn’t open very far.  The modern specimens had 1) significantly longer lower mandibles, 2) structural changes that allowed their mouths to open wider, and 3) larger upper mandibles. Accompanying the larger mandibles were more robust “hardware” for linking bone to muscle, with beefed up jaw muscles that enabled the tiny mice to feed on much larger food items than they had historically.

In the blink of an eye, geologically speaking, Prairie Deer Mice had shown measurable, obvious evolutionary adaptation in response to their new environment and food sources.  The researchers found high densities of deer mice in the middle of corn and soybean fields.  Some inevitably will succumb to the mechanical tools humans use to turn and manipulate the soil, but with such a rich, dense, bountiful food source, the mice had quickly evolved to fill the new ecological niche and feed on corn and soybean waste.

For a scientist like myself, I’m completely dumbfounded by the sheer ignorance of those who doubt science…who doubt climate change is real…who doubt in evolution.  The actual empirical evidence is overwhelming, conclusive, and “in-your-face”, for those who bother to open their eyes to the world around them. It’s a fascinating story, and the writer (Conor Gearin) did a great job not only summarizing the research, but telling it in a true story-teller’s fashion.  To me, this is exactly the kind of story, and writing style, that could perhaps help to turn the tide against the anti-science wave that seems to be cresting in the U.S. right now. Great story, and The New Territory really looks like a publication that’s worth subscribing to or picking up if you get a chance.

Grand River National Grasslands, Harding County, South Dakota

Expansive grasslands of the Grand River National Grasslands, in Harding County, in far northwestern South Dakota. Grassland habitat like this is greatly reduced in the Great Plains. However, that doesn’t seem to be a problem for one species, the Prairie Deer Mouse, who evidently can do quite well without an actual “prairie”.

Losing the Rainforests…and South Dakota habitat

This week the New York Times had a wonderful (as always), yet sad piece about deforestation in the Amazon rainforest. Approximately 360,000 acres in the region were deforested every year during the 1990s, a number that jumped to 660,000 acres a year during the early 2000s.  A massive push to slow deforestation rates occurred in the 2000s, temporarily slowing the rate of deforestation.  However, in the last few years the deforestation rate has skyrocketed, to over 850,000 acres every year, an area the size of Rhode Island. Every. Year.  Clearly that’s not sustainable.  Even the supposed “success” in the mid-2000s of slowing the rate of deforestation only “slowed” it, it certainly didn’t stop it or reverse the trend.  That’s the world we live in now, where SLOWING the inexorable loss of habitat is considered a major conservation success story, even if those slower rates still would have wiped out most of the rainforest during this century.

We don’t have rainforests in South Dakota.  From a birder’s perspective, we don’t have much bird habitat whatsoever in the eastern part of the state, given the preponderance of corn and soybeans that takes up the vast majority of the landscape.  Still, as a birder, I have reveled in the little reservoir pockets of remaining habitat, small micro-habitats where birds have thrived, despite the massive use of the landscape for agricultural production.  I used to bring my camera with me EVERYWHERE.  Every day when I went to work, my camera came with me.  I would stop at these little pockets of habitat, and take bird photos. Over the years, I’ve gotten some truly wonderful photographs in these small remaining pockets of habitat.

I don’t bring my camera with me to work any more. I don’t bring my camera with me when I run errands. In fact, I don’t do nearly as much birding right around Brandon and Sioux Falls as I used.  Much of the reason is that many of my former little micro-habitat “hotspots” are gone, something that’s just happened in the last several years.  There have been multiple reasons behind it.  The first is simple economics…with demand for corn and soybeans, farmers are cultivating every possible patch of land to maximize production. Fence rows, shelter belts, and other little pockets of habitat are being plowed under to expand planted acreage. There have also been active “safety” programs in the last few years to clear brush and trees from the edges of the roads.  It’s been a truly massive project, with roads all over the state undergoing this kind of “grooming”, removing habitat that is anywhere close to road edges.

We don’t have the rainforest like the Amazon, but habitat loss is having an impact right here in South Dakota.  Here are some small, and some larger, examples of what’s happening with habitat change in South Dakota, and how it’s affecting bird species. Bird photos accompanying each image are some of the actual bird photos I’ve gotten from each location over the years.

Ditch Road - Minnehaha County, South Dakota

Ditch Road, just north of Sioux Falls in Minnehaha County. There’s a stretch of road that runs over 5 miles that has a straight drainage ditch running along side it. In the last year, nearly all of the thick trees and shrubs that were found between the road and the waterway have been removed (the area encircled in red shows the vegetation that used to be there). It’s part of the aforementioned “safety” program to remove things that people could evidently crash into and get hurt.  (I always thought the point of driving was to stay ON the road). With the water and vegetation, it used to be an absolutely wonderful spot for songbirds and even some waterfowl, particularly in migration.  Warblers, Vireos, and Chickadees and Nuthatches, many woodpeckers, and other songbird species were often found here.  Not any more…

Big Sioux Recreation Area near Brandon, South Dakota

Big Sioux Recreation near Brandon, South Dakota – One that’s near and dear to my heart, given that we live on the edge of Brandon across the street from the park (house shown above). One of the best places to bird in the park used to be right amidst the campground areas themselves. The looped road shown above was lined with cedar trees, and thick brush separated many of the camping stalls from each other. The image above shows what it used to look like. The cedars in particular really attracted many birds, including one memorable winter when a hoarde of about 20 Long-eared Owls took up residence in the Campground (see photo above). In the last 2 years, all of the cedars have been removed from the campground area, as have most of the shrubs that separated camping stalls. If you want to play football? Thanks to all the vegetation clearing, it’s now MUCH more open in the campgrounds! If you really LOVE being close to other people while camping, with no pesky vegetation to get between you and the next guy, you’ll love the changes!  If you’re a bird lover? Not so much…

Minnehaha County Wetland

Minnehaha County Wetland — This one has a Google Earth image that actually catches the transformation as it happened. This is a small area in northern Minnehaha County on 253rd Street and near 481st Avenue.  Prior to 2015, the area in red was a mix of wetland, damp grasses, and weedy patches.  It was an absolutely WONDERFUL place to bird, a little patch of wet, weedy habitat that attracted species like Le Conte’s Sparrows, Swamp Sparrows, Bobolinks, Sedge Wrens, Marsh Wrens, and many other birds. In 2015, the owner installed drain tile, shown as the lines that run through the image above.  The drain tile dried out the land so it could be used for cropland, and today, this entire patch is a corn field. Drain tile installation has been RAMPANT in eastern South Dakota in the last few years. In some cases it’s been done to improve conditions on existing cropland.  In many areas though, like this, it’s being installed in areas that are naturally too poor to support crops, and need an artificial drainage system.  It’s hard to have Swamp Sparrows in an area, if you have no “swamp”.

South Dakota Shelterbelt

Shelterbelts – There aren’t a lot of woodlands and forests in eastern South Dakota, but the variety of birdlife in these little oases of trees can be truly astounding.  During migration they are definite bird “traps”, with tired songbirds stopped to rest and feed in these areas before continuing on with their migration. The photos are just examples of what you can find in these shelterbelts, as I haven’t birded this specific location before. However, it’s a great example of what’s been going on in much of South Dakota. This is north of Sioux Falls, near the intersections of Highways 121 and 122. This shelterbelt had been there the entire 23+ years we’ve lived in South Dakota, and it had some very large mature, old trees.  That changed last year, when all of the woody vegetation in the entire area circled in red was removed. This last summer it was all a big open field, planted in corn. There are many places in eastern South Dakota where this is happening, as farmers try to compensate for lowered corn and soy prices in the last few years by planting more and more acres.

Increase in Cropland Cash Rents - 2009 to 2014

What’s behind South Dakota cropland gains? — So what’s driving the agricultural change in South Dakota?  Beyond the little micro-habitat examples given above, there are some very large swaths of grassland being converted to cropland, with some much of the new cropland on land that had never been plowed before. The map above gives you some indication of the economic forces driving cropland gains in the state, and the concomitant loss of vegetated habitats.  Some of the largest recent changes in cash rent values for cropland in recent years are concentrated right in eastern South Dakota. As this article states, South Dakota had the largest increases in overall cropland value from 2004 to 2014, an increase of over 350% in just 10 years as average cropland values rose from $734 an acre to over $3,400 an acre. Prices for the major crop commodities of corn and soy have softened substantially in recent years, but that seems to have driven an intensification of land use in some parts of the state, as farmers try to maximize production by expanding the acreage that they plant.

Grassland conversion in the Great Plains

Grassland Conversion in the Great Plains – In 2013, colleagues/acquaintances published a paper the summarized the recent loss of grassland and wetland in the northern Great Plains. The map above shows the percentage of grasslands in an area that were converted to soybeans or corn between 2006 and 2011. Southern Iowa is a bit misleading, given that this shows “percentage” change, and there wasn’t nearly as much grassland there in 2006 as there was in parts of eastern South Dakota.  It really has been the eastern Dakotas where a huge chunk of cropland gains in the U.S. have occurred in recent years.  From a birder’s perspective…it hasn’t been a happy story.  Click here for the journal paper from Chris Wright and Mike Wimberly.

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