Sustainable RIVER
First year of the Sustainable RIVER Project
Summer 2017
The participants chose to document their experience through a blog, displayed below.
Welcome to the Sustainable RIVER Blog!
The Missouri River is a dynamic environment with complicated issues affecting different communities throughout the upper Missouri River basin. The Upper Missouri Basin extends from the river's source in Montana to Sioux City, Iowa. In this blog, we aim to discuss many of the most pressing challenges facing the Missouri River, as investigated by our research projects.
Our research includes social science, geophysical, and biological/ecological based projects, and guest bloggers may come from the Missouri River Institute, the University of South Dakota, the National Parks Service, the Army Corps of Engineers, and the Fish and Wildlife Service.
Utilizing ArcGIS to Map Land Use Change in Missouri River Watersheds
By: Ethan Jennings
My project in the Sustainable RIVER program this year was to develop an efficient method to digitally determine land use change along streams in a watershed. Previously, this work required labor-intensive field surveys or looking through historical satellite photos to get a rough idea of the changes. I was tasked with finding an more trackable and accurate digital method that monitored changes in infrastructure while still retaining an accessible database.
We used ESRI’s ArcGIS mapping software, as it is the industry standard, and searched for digital maps that could be used to determine watershed boundaries as well as land use change. Using U.S. Geological Survey (USGS) digital elevation models and ArcGIS Hydrology tools, we determined the extent of a small watershed; it’s a small watershed on the split rock creek drainage system. Using these tools, we saw how the watershed has changed over the years. We used this watershed at a set scale to calibrate our method to capture and record future changes. To determine land use change, we used images from the National Agriculture Imagery Program (NAIP); photos were taken from the air during the height of the growing season. This ensures that vegetation will likely be captured in the photos, and that the photos can be compared to one another because they will be captured around the same time each year. We analyzed and compared the imagery from 2005—2015; we tracked areas that experienced a change and merged them by using lines that made up the streams. This resulted in a massive body of data that detailed every stream that has experienced a land use change!
After a few tweaks, we increased the scale of the watershed and chose a larger river: The Little Vermillion. We made the work relevant to the present day by comparing 2006 to 2016 NAIP images. After a lot of hard work, processing time, edits, and corrections, we documented the many changes along streams within the small watershed on the split rock creek drainage system.
Ethan is a student at the University of South Dakota. He worked with Dr. Brennan Jordan (http://brennanjordan.org/) on his project for the 2017 Sustainable RIVER REU program.
A scaled image of the Little Vermillion Watershed that was on the split rock creek drainage system. Map made by E. Jennings and created using ArcGIS.
Little Vermillion Watershed map. Map made by E. Jennings and created using ArcGIS.
The Missouri River. Photo by Selena Olvera.
Above is a picture of a medicine wheel with the four sacred colors commonly used in Native culture. It also represents the four directions.
Colonizing the Mníšoše (Missouri River): Devastating Effects of the Pick-Sloan Plan
By: Selena Olvera, Sisseton-Wahpeton Dakota Oyate
Since time immemorial, American Indian tribes have inhabited the Upper Missouri River Basin. They have utilized the resources provided by the Missouri River, such as using native plants for medicinal and spiritual purposes. These tribal nations have fought for centuries to keep their relationship with the Missouri River. However, this relationship and usage was profoundly disturbed by the construction of dams following the enactment of the Pick-Sloan Flood Control Act of 1944. This act was created by Congress to have jurisdiction over the waters of the Missouri. As written in the act, Congress has jurisdiction over the river through navigation, flood control, and construction of dams (1). Indigenous people who originally resided in the floodplains of the Missouri were flooded as a result of dam construction, and were not given any type of compensation. Forty miles from the Gavins Point Dam in South Dakota, the community of Niobrara is affected with flooding when there is a major release. Historically, there are villages who lived on the floodplains of the Mnišoše. Because of the construction, these villages were flooded and are currently underwater (2). Throughout the summer I conducted interviews with members of two affected tribes. Specifically, one interview was conducted with a member of the Northern Ponca Tribe of Nebraska. The goal of my research was to highlight the impacts of dam construction along the Missouri.
Built in 1945, the Garrison Dam in North Dakota caused 185,000 acres of land to be taken away from the Arikara, Mandan, and Hidatsa tribes, now known as the Three Affiliated (3). This was a result of the Pick-Sloan Flood Control Act. Thousands of American Indians along the river were affected by the dams from the Fort Peck Dam in Montana to the Gavins Point Dam near Yankton, South Dakota which flooded out the Isanti (Santee) and Ponca tribes. Flooding areas for construction of the dams forced the tribal nations to leave their homes and be placed in reservation borders. Since reservation land was commonly infertile, growing crops was difficult. At least 95% of the best agricultural land was taken. To find jobs for better lifestyles, many left the reservations to more urban areas. After only being considered American citizens for two decades, racial tension was high which also made finding jobs difficult. The Assiniboine, Arikara, Mandan, Hidatsa, Húŋkpapȟa Lakȟota (Standing Rock), Mniconjou Lakȟota (Cheyenne River), Khulwičhaša (Lower Brule), Kȟaŋǧí Wakpá (Crow Creek), Ihaŋktuŋwaŋ (Yankton), Istáŋti (Santee), Omaha, and Ponca were all affected by the construction of dams.
Although the dams provide profit from hydroelectric power and tourist recreation, the indigenous along the Missouri River are still fighting for the rights taken away from us throughout the centuries. “The river is the source of life that connects us all to the Mother Earth and together as relatives. The people of the Očéthi Šakówiŋ (Seven Council Fires) are the caretakers of the Mníšoše (Missouri River) which in turn takes care of its inhabitants.
“Haŋ, mitakuyapi. Selena emáčiyapi nahaŋ Sisíthuŋwaŋ-Waȟpéthuŋwaŋ Dakhóta Oyaté.” Hello, relatives. My name is Selena and I am Sisseton-Wahpeton Dakota.” Selena is a junior at the University of South Dakota in Vermillion, South Dakota and double majoring in American Indian Studies and History. Previously, Selena has done an internship with the Indian Museum of North America at Crazy Horse and the Sustainable RIVER REU program at USD. Both have been ethnohistorical analyses of American Indian tribes in the Plains. She is currently pursuing a career in museum research to improve more appropriate research methods towards cultural intelligence.
Literature Cited
1. Flood Control Act of 1944, 58 Stat. 887 1940-1945
2. Interview with Ponca Tribal representative, June 2017.
3. Lecture given by Arikara Cultural Center, July 2017
We're Published in Research Features!
We're happy to announce that our article about the Sustainable RIVER project has recently been published in Research Features! It's titled, "A sustainable approach to environmental management". It discusses the complex Missouri River, the fantastic research that was conducted this summer, a Q&A with Dr. Meghann Jarchow (the program coordinator), and a few thoughts from program participants. Check out the attached file below to read the article!
If you have any questions, please contact Dr. Meghann Jarchow (Meghann.jarchow@usd.edu).
Bethany taking a sample along a Missouri River tributary.
Bethany holding up gear that is needed to survey the tributaries - waders!
Impact of Drought on Suspended Load in South Dakota Tributaries
By: Bethany Vazquez
The installation of Gavins Point Dam on the Missouri River has drastically influenced sediment loads. Dams can restrict the flow of the river, greatly reducing sediment loads downstream while also trapping sediment upstream. While too much sediment can be detrimental, too little sediment can also diminish ecosystem quality (Jacobson et al., 2009). I measured the suspended load of three major tributaries (Vermillion, Big Sioux, and James) below the Gavins Point Dam and looked at their overall contribution to the Missouri River sediment load. The state of South Dakota was enduring a severe drought during sampling from March to August 2017. As drought persists, the suspended load of sediment may continue to decrease until a heavy rain event takes place, which would subsequently mobilize the sediment, and alter the ecosystem.
Our three study tributaries vary in length and basin size, with the Vermillion being the smallest. The Vermillion also had the lowest discharge, while the Big Sioux had the highest. Using a depth integrated sampler, we collected suspended sediment from the water column at two locations in each river every other week. We observed a positive correlation between suspended load and variables such as total dissolved solids, salt, conductivity, and loss on ignition. Loss on ignition measures the amount of organic carbon in the suspended sediment, and can serve as a proxy for nutrient loads, which are essential resources for organisms living in the river environment (Grove and Bilotta, 2014).
The Vermillion was significantly different compared to the other tributaries in terms of nutrient load, containing two times the amount of organic carbon compared to the James and Big Sioux. In the Vermillion, the suspended load decreased as the discharge decreased. This might be due to settling of sediment in the water column while higher flows in the other tributaries would not allow this trend. In the Big Sioux and James rivers, suspended load remained relatively constant as discharge declined over the summer. The Big Sioux and James have a high enough flow to cause turbulence that mixes and dilutes the suspended sediment. Lack of correlation between suspended load and discharge in the other tributaries might be due to the bigger size of their basins and potential dilution taking place because of their larger discharges (Xu, 2014). The Vermillion River had the lowest discharge overall, yet had the highest suspended load and total dissolved solids values, which might indicate that more sediment erosion is occurring in this basin compared to the others. These tributaries are probably the primary nutrient source for the Missouri River (Wetzel et al., 2014), which saw a >90% reduction in suspended sediment loads after the Gavins Point Dam was constructed (Jacobson et al., 2009) Land use may also play a role in sediment load of these tributaries. Future research efforts will provide additional suspended load data as well as an analysis of land use for each tributary basin.
Literature Cited
Grove, MK, Bilotta, G.S., 2014, On the use of loss-on-ignition techniques to quantify fluvial particulate organic carbon. Earth Surface Processes and Landforms, v. 39, p. 1146-1152.
Jacobson, RB, Belvins, D.W., Bitner, C.J., 2009, Sediment regime constraints on river restoration – An example from the Lower Missouri River. In James, LA, Rathburn, S.L., and Whittecar, GR, eds., Management and Restoration of Fluvial Systems with Broad Historical Changes and Human Impacts. Geological Society of America Special Paper 451, p. 1-22.
Wetzel, R., Sweeney, M.R., and Cowman, T., 2013, Contributions of suspended load to the Missouri River downstream of Gavins Point Dam, Yankton, South Dakota, Geological Society of America Abstracts with Programs, v. 45, no. 7.
Xu, J, 2014, The influence of dilution on downstream channel sedimentation in large rivers: the Yellow River, China. Earth Surface Processes and Landforms , v. 39, p. 450-462.
Effects of Fish on Aquatic Insects
By: Tyler Seidel
Aquatic insects are an important source of energy for freshwater fishes and an important source of energy in linked aquatic-terrestrial food webs. However, the consumption of aquatic insects by fishes may reduce the energy available to aquatic and terrestrial food webs. Our research predicted that fishes would alter local food webs and affect ecosystem productivity. Emergence traps and fish exclusion cages were used to collect emerged aquatic insects from treatments with and without fish to determine the reduction of insect emergence by fishes to terrestrial ecosystems. Furthermore, fish and benthic communities were sampled and recorded, fish diets were sampled, and terrestrial insectivorous spider abundances were recorded. Research took place above and below an abandoned beaver dammed stream on the Missouri National Recreation River at Bow Creek Recreation Area in Cedar County, Nebraska, which contains both native fish and introduced fish.
Data suggests that the fish sampled at Bow Creek Recreation Area were primarily water column feeding fish and that the stage of aquatic insects consumed varied across species. Moreover, fish exclusion cages yielded higher emergent insect biomass above the former beaver dam, and that the terrestrial spider densities were higher above cages without fish than with fish. Results from our research will help to determine the direct and indirect effects of fishes on ecosystems, allow for the testing of new theory in ecology about the role of size-structured prey, introduce the potential role of fish species loss or introduction in linked aquatic-terrestrial food webs, and help to guide the conservation and management of the Missouri River.
Our results demonstrate that freshwater fishes can reduce aquatic insect emergence by 80%. The reduction of aquatic insect emergence biomass has direct effects on adjacent terrestrial ecosystems. Since aquatic insects support a variety of terrestrial consumers, one notable effect is the reduced abundance of aquatic prey consumers such as insectivorous terrestrial spiders. This trend may be translatable to higher order terrestrial consumers such as amphibians, reptiles, birds, and small mammals. Therefore, it is important to understand how fish communities are influencing the quantity of a resource that is utilized across ecosystems. For example, the consumption of aquatic insects by fish varied according to species. The variation in consumption patterns may promote disproportionate reductions in aquatic insect biomass in aquatic and terrestrial ecosystems.
Competitive pressures among freshwater fishes influences the respective predatory behaviors of fishes in order to reduce competition. The partition of foraging habitat among fishes prompts species-specific consumption rates that are dependent on the fish community present. Therefore, the abundance of aquatic insects consumed, including the life history stage of the aquatic insect, is dependent on which fish species are present. Our results may be of particular importance to consider for recreational or sports fishing. Conservation and management decisions should consider what fish species are present, what they are eating, and how supporting artificial populations of fish species influences the other covariates. In addition, the species-specific consumption rates of aquatic insects may influence riparian zone organisms through differential habitat use patterns. This trend is supported by the colonization and persistence rates of insectivorous terrestrial spiders. However, it is unclear how fish community composition indirectly influences other terrestrial species that are dependent on aquatic insects.
For more information, check out the following links:
Supplemental Readings
Baxter, C. V., K. D. Fausch, and W. Carl Saunders. (2005). Freshwater Biology, 201-220.
Polis, G.A., Anderson, W.B. & Holt, R.D. (1997). Annual Review in Ecology, Evolution, and Systematics, 289-316.
Nakano, S., and M. Murakami. (2001). PNAS, 166-170.
Wesner, J. S. (2016) Oecologica, 1205-1211.
Tyler checking an emergence trap at Bow Creek Recreation Area
An image reflecting the effect of fish on emerging insects. Mesocosoms with fish reduced aquatic insect emergence.
Example vegetation plot with necessary materials for harvesting and identification
Aleisa in action harvesting grasses and forbs from the vegetation from the test plot
Pictures by Eva Soluk Allison Bowers and Shelly Kosola
When C3 plants were paired with C4 plants, early-flowering forbs, and late-flowering forbs, the C3 plants overyielded. However, when later-flowering forbs were paired with the other groups, they underyielded.
Time of Plant Establishment Affects Prairie Composition
By: Aleisa LaBelle
Sustainability, a cross-disciplinary field, focuses on maintaining the earth’s ecosystems for future generations while improving human well-being. For years, humans have been using the land in a way that satisfies economic stakeholders, and aren’t always focused on allowing ecosystems to flourish into the future. In the United States, native prairies are decreasing, which is primarily due to past and current conversion to agricultural land. Several scientific studies have been performed or are in progress to evaluate potential benefits of managed prairie systems, including haying grasses for animal feed or biofuels, or to increase pollinator levels near agricultural fields (Jarchow & Liebman 2011). The results of these studies aim to encourage land managers to restore and maintain diverse prairie systems. By incorporating sustainability practices into prairie research and agricultural practices, we can hope to preserve today’s beauty and biodiversity for future generations.
I helped conduct research on prairie systems in the 2017 Sustainable RIVER REU program. For my research, I assisted with the Comparing Managed Prairie Systems (CoMPS) experiment near Vermillion, SD. I used data from the treatments that contained different prairie functional groups, including warm-season grasses, cool-season grasses, early-flowering forbs, and late-flowering forbs, grown alone and grown in pairs (for a total of 10 treatments). The research hoped to quantify whether each functional group overyielded or underyielded when grown with the other functional groups. A functional group overyielded when the amount of aboveground biomass that the group produced when paired with another functional group was higher than the yield it produced when grown alone (Hector & Loreau 2001). Conversely, a functional group underyielded when the amount of aboveground biomass that the group produced when paired with another functional group was lower than the yield it produced when grown alone (Hector & Loreau 2001). Measuring overyielding and underyielding helps to evaluate the relationship between increasing diversity and productivity.
To gather data for my research project, I conducted fieldwork, which included harvesting plants and identifying plant species. To further inform my research question, I also incorporated data previously collected in July of 2015 and 2016 by a graduate student. My main finding was the cool-season grasses tended to dominate all other functional groups (i.e. overyield), but the abundance of the warm-season grasses was increasing over time (Figure 1). The forbs were not well established in the experiment yet. Because the cool-season grasses started growing earlier (in the experiment and in the year), they were able to get established and exclude other functional groups.
Overall, this project helped enhance my research skills and provided me the opportunity to learn more about the complexities of prairie ecology.
Click on the following links to learn more about prairie ecosystems and the research that is ongoing!
Aleisa is from Sioux City, IA and is currently studying general sciences at the Nebraska Indian Community College. She was part of the 11-week 2017 Sustainable RIVER REU, and researched prairie conservation with a sustainability focus with her research mentor Dr. Meghann Jarchow.
Literature Cited
Jarchow, M. E., & M. Liebman. 2011. Incorporating prairies into multifunctional landscapes. Extension and Outreach Publications. 48 <http://lib.dr.iastate.edu/extension_pubs/48>.
Loreau, M., & A. Hector. 2001. Partitioning selection and complementarity in biodiversity experiments. Nature, 412(6842): 72-76.
Importance of Maintaining the Diverse Tallgrass Prairie
By Shelley Kosola
Prairie lands once inhabited approximately 170 million acres across North America (Figure 1; NPS 2015). Yet today, only 1% of the original tallgrass prairie remains (Sampson and Knopf 1994). The loss in tallgrass prairie was caused primarily by conversion of the land for agriculture, especially row-crop agriculture. There are currently large losses of grasslands, including prairie, in the Western Corn Belt due to continued expansion by row-crop agriculture (Wright and Wimberly 2013). Continued destruction and increased isolation of tallgrass prairies threatens this important, and once dominant, ecosystem.
Prairie systems are remarkably complex and diverse. On average, 80% of the prairie is composed of grasses (40-60 species) and the other 20% consists of forbs (~300 species), lichen, and liverworts (~100 species) (NPS 2015). Each of those species plays an intricate role in sustaining a thriving environmental community or niche. Diversity is a key element in creating balance within those ecosystems. An analysis by Dr. Forest Isbell and colleagues (2011) of grassland systems found:
Different species promoted ecosystem functioning during different years, at different places, for different functions, and under different environmental change scenarios. Furthermore, the species needed to provide one function during multiple years were not the same as those needed to provide multiple functions within one year… although species may appear functionally redundant when one function is considered under one set of environmental conditions, many species are needed to maintain multiple functions at multiple times and places in a changing world.
Literature Cited
Isbell F., Calcagno V., Hector A., Connolly J., Harpole W.S., Reich P.B., et al. (2011) High plant diversity is needed to maintain ecosystem services. Nature 477: 199-203.
NPS (2015) A complex prairie ecosystem. National Park Service. Retrieved from https://www.nps.gov/tapr/learn/nature/a-complex-prairie-ecosystem.htm.
Sampson F. and F. Knopf (1994) Prairie conservation in North America. BioScience 44(6): 418-421.
Wright C.K. and M.C. Wimberly (2013) Recent land use change in the Western Corn Belt threatens grasslands and wetlands. Proceedings of the National Academy of Science 110(10): 4134-4139.
Figure created by U.S. Fish and Wildlife Service
Photo by Meghann Jarchow
Mapping the Missouri
By: Becca Krasky
Today’s Missouri River looks incredibly different from the Missouri River explored by Lewis and Clark from 1804 to 1806 on their historic “Voyage of Discovery”. They traversed a wild river, called the “Big Muddy”, so named because of its massive sediment load, winding through a floodplain up to twenty miles wide (Schneiders, 1999). The banks and floodplain were forested with a successional variety of trees, including towering cottonwoods. Bison and elk roamed the prairie, and the river was inundated with native fish.
Today, much of the cottonwood forest is gone because of conversion to agriculture. The river is controlled by six mainstem dams north of Sioux City, Iowa, and channelized from Sioux City to its confluence with the Mississippi in Missouri. It flows in a straight, deep channel, with much of its sediment trapped by the dams. Native fish are maladapted to the fast flowing and dammed river, and struggle to compete with invasive species, such as silver carp. Two endangered shorebirds, the Piping Plover and Least Tern, and one native fish, the Pallid Sturgeon, are several species affected by the damming of the river, and are protected under the Endangered Species Act (Lawson, 2009).
So, why has the river changed so much? The present-day Missouri River reflects South Dakota’s past of colonialism, and the state’s entrenched reliance on the global economy for trade of the state’s natural and human resources (Dhillon, 2017). This can be seen in the loss of almost all the state’s native prairie, its shrinking wetlands, and the dammed Missouri River. South Dakota’s prairie was willingly sacrificed to grow commodity crops, such as corn and soybeans. The state’s original Indigenous inhabitants, the Arikara/Sahnish, Dakota, Lakota, and Nakota Sioux, were robbed of much of their land and were forced to move to reservations. Through the Pick-Sloan Plan, the Missouri River was dammed in the 1950s and 1960s to protect downstream cities from flooding (Lambrecht, 2005); however, this Plan allowed the flooding of entire reservation communities, inundating their most fertile land, sacred sites along the river, and ancestral homes (Lawson, 2009). South Dakota’s white government and white settlers have always had priority in dictating the uses of the state’s landscapes.
So, what’s the future of the Missouri River in South Dakota? Will it always be restrained by dams, dikes, and bank stabilizers? Or will it be allowed to be wild, meandering throughout the floodplain, and maintaining natural flooding regimes? I wonder whether valuation and quantification of essential ecosystem services, tangible benefits to people provided by the environment, could help residents of the Upper Missouri basin recognize how valuable a restored Missouri River might be. River management is a complicated issue, with numerous stakeholders, and as history has shown, decisions about land use have profound implications for the future. Our actions today will dictate how future South Dakotans interact with the Missouri, and as caretakers of this land, it is our responsibility to carefully evaluate options for river management.
Would you like to learn more about these issues?
My top book recommendations from this summer are, in no particular order:
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Dammed Indians Revisited: The Continuing History of the Pick-Sloan Plan and the Missouri River Sioux by Michael Lawson
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Big Muddy Blues: True Tales and Twisted Politics Along Lewis and Clark’s Missouri River by Bill Lambrecht
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Strangers in Their Own Land: Anger and Mourning on the American Right by Arlie Russell Hochschild
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Prairie Rising: Indigenous Youth, Decolonization, and the Politics of Intervention by Jaskiran Dhillon
Becca is a junior at Macalester College in St. Paul, Minnesota and is majoring in Environmental Studies and Geography. She spent this summer researching how South Dakota’s landscape has changed over the past three hundred years, and created maps to reflect these changes. Her research included reading over ten books about the state’s rural geography and history.
Literature Cited
Dhillon, J. (2017). Prairie Rising: Indigenous Youth, Decolonization, and the Politics of Intervention. Toronto: University of Toronto Press.
Lambrecht, B. (2005). Big Muddy Blues: True Tales and Twisted Politics Along Lewis and Clark’s Missouri River. New York: Thomas Dunne Books.
Lawson, M. L. (2009). Dammed Indians Revisited: The Continuing History of the Pick-Sloan Plan and the Missouri River Sioux. Pierre, SD: South Dakota State Historical Society Press.
Schneiders, R. K. (1999). Unruly River. Lawrence, Kansas: University Press of Kansas.
Searching for the False Map Turtle
By: Shay Austin
As part of my Sustainable RIVER experience with the Kerby Lab, I helped survey along the 800 miles of shoreline of Lake Oahe, a large reservoir on the Missouri River, to search for false map turtles (Graptemys pseudogeographica). Before coming to Vermillion, South Dakota, I had never heard of the false map turtle! I soon realized the importance of this research because no one knew if this state-threatened species still existed in Lake Oahe. I figured I would learn a lot about these charming creatures during the three weeks I spent scanning Lake Oahe with binoculars and setting turtle traps in every nook and cranny of the reservoir. Although I learned a lot, I did not see a SINGLE false map turtle in Lake Oahe. We slept in tents along the Oahe shoreline and weathered five-foot swells in a little johnboat, but by the end of the trip we couldn’t report a single false map turtle sighting from Pierre to North Dakota.
The lack of false map turtles was particularly shocking because a study from the early 60s revealed that the area used to contain the highest abundance of false map turtles in the state1. The natural question is, what happened?
Before dams were constructed on the Missouri River, the river was large, allowed to naturally meander, and was uncontrolled. Now, each of the six main stem dams controls the flow of the river, creating large flooded areas upstream from the dams called reservoir lakes. Lake Oahe is the largest of these areas on the Missouri. In fact, it is so large, that it can be seen from space!
Dams and reservoirs are known to drastically change the ecology, geology, and hydrology of the river. It seems that the false map turtle can’t thrive in this reservoir habitat. This isn’t a surprise; false map turtles are reported at higher densities in moving waters1.
We can’t say for certain that there are absolutely no false map turtles in Lake Oahe, but it seems unlikely – especially considering how easy they are to spot in the flowing Missouri river by Vermillion. We could find dozens of false map turtles in a just a couple of hours in the flowing water habitat. They clearly prefer the natural current that exists there. A major aspect of the habitat is the snags, or sunken logs that protrude from the water, which are abundant in the shallow, moving stream. The turtles need places to bask to maintain an optimal body temperature, and snags are perfect beach chairs.
So, it’s more than likely that the Oahe reservoir destroyed the false map turtle habitat. The next question I investigated was if there were any threats to the turtle in the free-flowing stretch of the river. The turtles appear to be very abundant in this area, but is there anything creeping in the water that could endanger the health of the population?
One thing that is impossible to miss while driving in eastern South Dakota is the seemingly never-ending agricultural fields of corn and soybeans, nearly all of which use herbicides and pesticides to maintain their yields. Unfortunately, these chemicals can pollute nearby streams and tributaries and eventually find their way to the Missouri.
The most commonly used herbicide worldwide is Roundup®. The active agent, glyphosate, is present in nearly all Midwestern streams, and it is known to kill bacteria2. I wanted to find out if glyphosate had any major impact on the microbiome of false map turtles, seeing as changes to the microbiome is known to affect disease susceptibility and individual fitness3. I collected ten turtles from the main stem of the Missouri River and brought them back to the lab to run an experiment. I kept the turtles in individual tubs and randomly dosed five of them with Roundup®. Cloacal swabs taken before and after the treatment will soon be analyzed for bacteria species and diversity to see if glyphosate had an impact on the bacterial composition of the dosed turtles.
Additionally, when turtles were captured, we took a blood sample to later test for ranavirus; detection of ranavirus in turtles would be the first for the state. There may also be a correlation between presence of ranavirus and the types of bacteria found in the turtles.
The work on Lake Oahe will continue for at least another year, and the lab is continuing to venture into the little explored ecological communities of microbiomes. The Kerby Lab is a prolific hub made up of hardworking people that I was happy to be a part of. I’m certain that there are more exciting studies and discoveries to come.
Check out the following links to learn more about the Kerby Lab and the amphibian and reptile research that is ongoing!
Shay is a senior pursuing her Program in the Environment major at the University of Michigan. She participated in the 11-week Sustainable RIVER REU in 2017, and researched the effects of contaminants on the false map turtle microbiome with her research mentor Dr. Kerby. Shay hoped to pursue a career in sustainability or in a wildlife program.
Literature Cited
1. Timken, R.L. (1968). The Distribution and Ecology of Turtles in South Dakota (Doctoral dissertation).
2. Scribner et al. (2002). Reconnaissance Data for Glyphosate, Other Selected Herbicides, Their Degradation Products, and Antibiotics in 51 Streams in Nine Midwestern States, 2002. USGS Open-File Report 03-217, 101 pp.
3. Knutie et al. (2017). Early-life disruption of amphibian microbiota decreases later-life resistance to parasites Nature Communications. 8: 86.
Young false map turtle.
Boat used to survey Lake Oahe
Example of how turtle traps were set in Lake Oahe
Experimental tank were false map turtles were exposed to roundup and their microbiome was sampled.