Cropland with Eastern Kingbird, Praying Mantis, Western Meadowlark, Northern Leopard Frog, Plains Spadefoot.
Last year, I applied for an internship at Science Friday. This was one of the clips I sent with my resume.
It’s been quietly happening, here, the change. Even if you live next to it, you won’t even know it’s happening.
What is this mysterious phenomenon? It’s the Western Corn Belt, and it’s creeping westward. Once defined as the row-crop concentrated area that stretched from Minnesota to Missouri, now it’s overtaking the Prairie Pothole Region in the eastern Dakotas.
Why is this region important? First, we have to understand the Prairie Pothole Region’s natural history. Formed by glaciers in the Pleistocene, these divots of natural wetlands have been a repository for great productivity in plant life and as natural aquifers.
Now those oases of life have come under a threat. In the mid-2000s, soy and corn prices doubled as interest in biofuels, like ethanol, surged, as did farmers’ interest in converting their remaining prairies and wetlands to row-crop. Decades of enrollment in federal programs like the Conservation Reserve Program severely dipped, according to a 2013 paper by Christopher Wright and Michael Wimberly of South Dakota State University. Now, 10 years later, an area the size of Kansas has been converted from grassland to row crop in the Northern Plains, according to World Wildlife Fund’s annual plowprint report in 2016.
This is not the only Northern Plains biome affected by this wave of alternative fuel production. Wetlands adjacent to the newly converted grasslands in the Prairie Pothole Region have been affected by the soil erosion that spills over from the neighboring row crop lands. Often, points out Wright and Wimberly, these lands were marginally arid to begin with, and thus are subject to any change in the soil composition surrounding them.
Loss of grasslands has a host of associated issues, many of which undermine the very productivity of the new row croplands, including declining soil quality and increasing flood risk. This, according to Wright and Wimberly, is all exacerbated by changing climate trends for the region which include an increase in temperatures and changing precipitation.
What does this mean for wildlife? Migrating birds have used this vast network of wetlands and prairie for millennia as stopover points in their quest to travel north in the spring and south in the fall.
The change in the wetlands and grasslands might be a quiet revolution. However, the millions of migrating waterfowl, songbirds, cranes, and shorebirds are anything but quiet.
Imagine, at the height of spring migration, 20,000 snow geese passing overhead every few minutes. Unless you have been awoken by this every day for a month like the locals have, you’ll never know the sheer force of nature that relies on these oases. Many of these species stay to breed for the summer. Many more rely on the wetlands and grasslands for refueling on their great trek.
Some of these migrations draw a crowd. On a chilly morning in March, a small horde gathers at sunrise to see tens of thousands of Sandhill Cranes lift off from Nebraska’s Platte River. It happens fast, and if you miss it, you’ll have to wait until sunset for them to come back. It’s a rare sight, and many of the folks trudging back to their cars in the dim foggy sunrise wouldn’t call themselves bird watchers. For many people, it’s a chance to see something akin to the great wildebeest migration on the Serengeti Plain. For the state of Nebraska, it’s a boon to the tourism industry.
It’s not just for the birds. Participation is growing for Frog Watch, a citizen science initiative that counts amphibians in the vein of the Breeding Bird Survey or the Christmas Bird Count. An attention to these species means a growing interest in the Prairie Pothole Region’s aquatic ecosystem during this time of change. Arthropods that are affected by agricultural intensification and its associated pesticide spraying remain an important part of the aquatic ecosystem, and fish, amphibians and other invertebrates are feeling the downstream effects. This is intensified by the use of tile drainage in agricultural fields in which runoff is sloughed off and accumulated in neighboring wetlands. How this affects the ecotoxicology and the assemblage of animals in the aquatic food web is currently being investigated by several regional researchers.
What can we do for the dwindling prairies and wetlands? Biofuel production was high for many years, and now more recently there is an annual surplus of corn and soy produced. Crop prices have declined in the past few years as a result, and it’s an opportunity for The Nature Conservancy, the National Wildlife Refuge system, and a host of other state and local agencies to buy acquire from farmers under the easement process. Farmers are looking to unload some of their less productive land around wetlands, and there is now a waitlist, points out National Wildlife Refuge managers. Fortunately, U.S. Fish and Wildlife, which manages the National Wildlife Refuges, recognized the opportunity and focused Duck Stamp funds toward easement acquisition in the Prairie Pothole Region. However, with a new presidential administration in 2017, it’s unknown whether this buyback directive will continue.
Even as some of the land returns to grassland and wetland, it’s a lesson for future crop price booms. As land managers in South Dakota and Minnesota point out in a 2016 episode of Pioneer Public Television, prairie restoration isn’t easy. Less than two percent of grasslands remain nationwide, and once a prairie is converted to row crop, you can never fully restore it. Invasive species will always attempt entry back into the system. Fire, grazing, hay harvest, brush control and re-seeding are all required to maintain a restored prairie. Invasive plants include red cedar and elm, plants that are remnants of the shelter belts planted in the Great Depression to mitigate the soil-eroding Dust Bowl winds. Moreover, land managers have to tread lightly. Pesticides take out not only mosquitoes, but pollinator species, such as the beloved Monarch Butterfly, and as pointed out in a 2014 issue of Nature, neonicotinoid pesticides are associated with the decline of beneficial aerial insectivores, like bats, swallows, swifts and nighthawks.
Added to the decline in natural habitat is the threat of rising temperatures. Animals that live in open areas like prairies are especially vulnerable to climate change. A 2016 paper by Jessica Gorzo in The Condor explains this trend. With rising temperatures and drier conditions comes a loss of production in tall plants that support nesting sites for birds like the threatened Grasshopper and Baird’s Sparrows. Sudden wild fluctuations in temperatures or rainfall can slow vegetation growth. It’s like a one-two punch.
There is some good news on the horizon. University of Nebraska Ph.D. student Maggie Sliwinski spent some time talking to ranchers in Nebraska, as reported by Dana Kobilinsky for The Wildlife Society. Cattle ranchers are increasingly open to making their land hospitable for wildlife by adopting fire management regimes, leaving the lands as a heterogeneous quilt of ungrazed and grazed patches, and mixing it up year-to-year. In return, the grass productivity increases in the long term. Sliwisnki doesn’t know whether ranchers in other areas feel the same way, but she plans to expand her survey to an additional 3,000 ranchers in the Northern Plains.
It’s not all gloom and doom. Some wildlife have adapted to shorter grasses found in grazed areas, as The Nature Conservancy’s Marissa Ahlering and Chris Merkord reported in a 2016 issue of The Journal of Wildlife Management. The long history of bison clearing the way for ground-nesting birds has left some thirsting for the voracious grass-guzzling appetite of cattle. Some grassland birds thrive under the right conditions if land managers instead choose to hold onto their prairies and graze.
Understanding how to make a living with the land while maximizing its ecological potential might be the key to the future. In 2016, the National Science Foundation awarded a $2 million grant to the University of South Dakota’s Sustainability Program to study the bioenergy industry and its potential contribution to carbon sequestration and habitat loss in the Missouri River Basin, interactions with hydraulic fracking, and effects on water quality. The goal is to then convene a group of citizens, scientists and governmental agencies to share ideas and evaluate the region’s future in sustainable energy development. So, the push for bioenergy development in the Prairie Pothole Region might not be a quiet revolution for much longer, and what this region decides to do with its remaining two percent of grasslands is up in the air.
To see a video of the Sandhill Crane migration, go here.
To see a video of the Snow Geese migration, go here.
Ahlering, M. A. & C. L. Merkord 2016. Cattle grazing and grassland birds in the northern tallgrass prairie. The Journal of Wildlife Management 80: 643-654.
Ewald, M. 2016. USD Part of NSF Environmental Research Project. Accessed at: http://www.usd.edu/news/2016/usd-part-of-nsf-environmental-research-project#.V9G4lzeGCRA.facebook
Gage, A.M., Olimb, S.K., Nelson, J. 2016. Plowprint: tracking cumulative cropland expansion to target grassland conservation. Great Plains Research 26: 107-116.
Gorzo, J. M., Pidgeon, A. M., Thogmartin, W. E., Allstadt, A. J., Radeloff, V. C., Heglund, P. J., & Vavrus, S. J. 2016. Using the North American Breeding Bird Survey to assess broad-scale response of the continent’s most imperiled avian community, grassland birds, to weather variability. The Condor, 118: 502-512.
Hallmann, C. A., Foppen, R.P.B, van Turnhout, C.A.M., de Kroon, H., & Jongejans E. 2014. Declines in insectivorous birds are associated with high neonicotinoid concentrations. Nature: July 9.
Kobilinksy. D. 2016. Student poster project: wildlife biologists working with ranchers. The Wildlife Society. Accessed at: http://wildlife.org/student-poster-project-wildlife-biologists-working-with-ranchers/
Prairie Management. 2016. Pioneer Public Television. Accessed at: http://video.pioneer.org/video/2365915066/
Wright, C. K. & M. C Wimberly. 2013. Recent land use change in the Western Corn Belt threatens grasslands and wetlands. Proceedings of the National Academy of Sciences 110: 4134-4139.
(Various interviews with University of South Dakota Biology Department and South Dakota State University researchers and National Wildlife Refuge managers.)