2026 Science Symposium
Titles & Abstracts
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PRESENTERS
Presenter: Dr. Meghan Midgley, Director of Science, Morton Arboretum; Dr. Nick Barber, San Diego State University Title: Impacts of Bison Grazing and Plant Composition on Soil Functioning: Lessons from Nachusa Grasslands and The Morton Arboretum Abstract: While plant community composition and diversity are frequently used to evaluate restoration success, people also seek to restore prairie functions, such as soil carbon storage and nutrient retention. In this project, our goal was to identify plant community characteristics that would allow us to predict how real, restored prairies function belowground. We used two sites to achieve this goal: a plant biodiversity experiment at The Morton Arboretum and Nachusa Grasslands. At the Arboretum, we found that as the abundance of Asteraceae increased, the amount of carbon stored in the soil increased, and the amount of nitrogen available to plants and microbes decreased. When we turned our attention to Nachusa Grasslands, we found a similar pattern: in the bison-grazed areas, soil contained more carbon and less nitrogen than in bison-free areas. Bison prefer to eat grasses, leaving behind plants that have thick leaves and stems. As a consequence, Asteraceae are much more abundant in bison-grazed areas than in bison-free areas. While the bison may be directly altering soil chemistry through other activities, our observations collectively point to a new “rule of life”: the abundance of Asteraceae in a restored prairie is a good indicator of soil functioning and ecosystem service provision. Presenter: Michael Yonker, Jack Breiter, Dr. Gavin McNicol; Department of Earth and Environmental Sciences, University of Illinois Chicago Title: Quantification of restored prairie soil greenhouse fluxes along environmental gradients Abstract: Agricultural land-use in former Midwest prairies emits globally significant quantities of the greenhouse gases carbon dioxide, methane, and nitrous oxide. However, the greenhouse gas emission reductions associated with prairie restoration remain unquantified, preventing a full evaluation of the benefits of restoration. During 2023-2025, we directly measured soil greenhouse gas emissions monthly during the growing season and once in winter using 65 chambers spread across an elevation gradient from woodland knolls to buttonbush wetlands in Tellabs West (Stone Barn Savanna) at Nachusa Grasslands. We found upland soils to be strong carbon dioxide sources, woodland soils to be strong methane sinks, and all soils to have approx. zero nitrous oxide emissions. We used linear regression to assess whether ecosystem cover type (woodland vs. prairie), temperature, moisture, elevation, and soil properties explained variability in observed fluxes, finding strong associations with variations in temperature temporally and moisture spatially. In sum, our results suggest that high quality prairie restoration significantly reduces greenhouse gas emissions by re-stabilizing organic matter and reducing excess nutrients. Future work will explore the ecosystem greenhouse gas balance, including plant canopy fluxes, through upscaling. Presenter: Dr. Tyler Karp, University of Chicago; Eva Savard, University of Chicago; and Dr. Elizabeth Bach, The Nature Conservancy Title: The impact of bison grazing intensity on burned area in tallgrass prairies Abstract: Nachusa’s management decision to concentrate the bison in the North Unit during the 2025 growing season presents a perfect opportunity to not only test how changing grazing intensity impacts total burned area, but also to test which mechanisms (fuel load reductions, plant community changes, or landscape disturbance) are responsible for any observed reductions. To this end, we set out to quantify fuel loads, burned area, plant functional traits, grazing lawn area and wallow area before and after the bison were moved. We present preliminary data and outline lessons from the field and the last year of the project. This project will help us better understand and quantify how bison management impacts fire management at Nachusa. Both of these processes are regulated by managers and understanding more explicitly how they interact via shifts in landscape structure and grass community function will help managers to make more informed decisions about their application. Presenter: Dr. Rich King, Northern Illinois University Title: Nachusa Grasslands Blanding’s Turtle Monitoring and Management, 2014-2025 Abstract: The Blanding’s turtle is threatened by habitat loss and degradation, elevated rates of predation, and human-caused mortality. It is listed as endangered in Illinois where most remaining populations are small and isolated. A small Blanding’s turtle population at Nachusa Grasslands has been the focus of monitoring and recovery since 2014. This population consists of 19 known wild turtles recruited without human intervention, 87 hatchlings from nests that were caged to exclude predators, and 62 headstarted turtles that were reared in captivity and released. Radio telemetry has provided information on nesting patterns, centers of activity, and overwintering locations and revealed that most wild turtles move off-site for extended periods. Data from Nachusa and other release sites demonstrate that nest caging and headstarting can aid population recovery. However, few adult females remain at Nachusa, limiting the number of headstarts that might be produced. Movements by Blanding’s turtles between protected and unprotected lands further constrains conservation efforts. Potential solutions include increased coordination among state and non-governmental agencies to establish reciprocal translocations of headstarts among sites and land acquisition or the establishment of conservation partnerships with private land owners. Presenter: K C Carter, Illinois Natural History Survey and University of Illinois Urbana-Champaign Title: Using zoo-centric metabarcoding to identify bumble bee-plant interactions within Nachusa Grasslands Abstract: The rapid loss of temperate grasslands has contributed to declines in bumble bees by reducing the diversity and quality of floral resources. Research at Nachusa Grasslands in 2025 examined how habitat quality influences bumble bee-plant interactions using zoo-centric DNA metabarcoding and network analysis. During the 2025 field season, 3,665 bumble bees representing 11 species were surveyed, and 195 corbicular pollen samples from 9 species were analyzed. Metabarcoding identified pollen from 328 plant species*, far exceeding the 81 species detected through field observations alone, indicating that traditional surveys may underestimate plant use. The resulting network included 799 unique interactions among 9 bumble bee species and 328 plant species* (184 native species, 58 non-native species, 81 not recorded in the INHS Illinois Plants Database – these plants were included only at the genus level, and 5 species origin was unrecorded). Several plant genera, including Amorpha, Baptisia, Cirsium, Eryngium, and Trifolium functioned as module hubs and supported multiple bumble bee species within subsets of the network. Most plant taxa were classified as peripheral, and no connector or network hub species were detected, suggesting interactions were evenly distributed, with no structurally dominant species. Bumble bee species differed in foraging behavior, with Bombus impatiens exhibiting the highest number of interactions and B. vagans showing the most even, yet specialized use of floral resources. Ongoing analyses will integrate nutritional profiling and comparisons among degraded, restored, and remnant habitats. The overall results identified native plant species that provide high-quality forage and can serve as alternatives to commonly used non-native species. These findings aim to inform restoration strategies that enhance pollinator habitat and support bumble bee communities in Nachusa Grasslands. Presenter: Ethan Rose, Michigan State University Department of Plant Biology Title: Water shapes bison reintroduction outcomes in tallgrass prairie Abstract: Grazing is an important natural process in grasslands around the world. In the tallgrass prairie ecosystem, bison maintain biodiversity by creating patchy disturbance where new species can establish and selectively consuming grasses that may otherwise over-dominate. Reintroducing bison to their historic habitats may aid in management by increasing biodiversity and habitat quality, but existing research findings are inconsistent. The tallgrass prairie spans a broad gradient of water availability, and ecological theory predicts that native herbivores have a stronger positive effect on plant diversity in resource-rich habitats with high competition for light and space. Conversely, resource-poor habitats should see neutral or negative effects from grazing as plants struggle to regrow. To test ecological theory and the use of bison as a management tool in the tallgrass prairie, I sampled plant communities at 8 remnant and 3 reconstructed reintroduction sites spanning much of the ecosystem’s moisture gradient. I found that bison-grazed communities overall had different species composition, higher richness, higher forb cover, and lower warm-season grass cover than ungrazed communities. However, these effects were tied to moisture availability with the driest sites showing no change. Interestingly, floristic quality was relatively unchanged. These results demonstrate the context-dependance of bison reintroduction success in this imperiled ecosystem. |
POSTERS
Presenter: Kamal Ehrlich, Dr. Holly Jones, Dr. Elizabeth Bach, Northern Illinois University; The Nature Conservancy Title: Secret Invasion: the hidden soil seedbank of birdsfoot trefoil supports its longevity Abstract: Invasive species present one of the most dire threats to biodiversity worldwide, and human-driven non-native introduction has aided their longevity. The non-native pasture crop birdsfoot trefoil (Lotus corniculatus) has a centuries-long history of agricultural use, but its invasion of native Midwestern ecosystems is understudied. Despite decades of eradication efforts, birdsfoot trefoil populations endure throughout the prairies of Illinois. A primary mechanism of birdsfoot trefoil’s persistence is seedbank accumulation, or the presence of dormant seeds after the progenating plant populations have left, leading to invasive population resurgence despite ongoing treatment. This study assessed the invasibility of birdsfoot trefoil in the restored prairies of Nachusa Grasslands in three site-types: high invasion sites, low invasion sites, and non-invaded sites. To determine the seedbank density relative to the plant cover, the overall percent cover of birdsfoot trefoil was measured at each site. Soil cores were sampled through systematic random plot sampling and the percent cover of birdsfoot trefoil within an area of 1m² was quantified at each soil core. Seedling counts were generated through seedling emergence in greenhouses. Using linear regression, this study found a strong positive relationship between the plant cover and seedbank density of birdsfoot trefoil in high invasion sites, indicating that the plant cover increases with seedbank density in high invasion sites. This regression was statistically significant (R² = 0.8376, F(1, 7) = 42.26, p = 0.0003339). The study will examine this relationship within low invasion sites and analyze this relationship between sites in the same treatment type. By examining seedbank density across plant spatial distribution, this study projects current and future range expansions of invasive birdsfoot trefoil through seedbank distribution. Future research will continue to assess the seedbank density of birdsfoot trefoil and utilize pre-emergent treatment to understand how birdsfoot trefoil seedbank presence can be addressed through invasive management. Presenter: Dr. Ryan Klopf, Dr. Pheobe Judge, Virginia Tech University; Dr. Elizabeth Bach, The Nature Conservancy Title: Plant community composition and soil carbon & nitrogen in restored tallgrass prairie before and after bison reintroduction Abstract: The goal of this project is to quantify the effects of bison on plant community structure as well as total soil carbon (C) and nitrogen (N) in tallgrass prairie restorations ten years after bison reintroduction. To accomplish this, in 2025 plant species richness and percent cover was measured in restorations with (n=8) or without (n=6) bison and compared with these same measurements first taken in 2008 prior to bison reintroduction. Soil (0-10 cm) was also sampled within each of these restorations to compare total soil C and N in 2009 and 2025. One grazed remnant prairie was also sampled to use as a reference for community and soil measurements. Plant communities were quantified using 1m² quadrats placed every 5 meters along transects located within similar soil series of each restoration. Species richness and cover was assessed in May and August 2025, with the maximum cover value for each species used to calculate Shannon-Wiener Diversity (H'). Soil (0-10cm) for C and N measurements was composited from ten 2 cm diameter soil cores taken along each transect. Presenter: Dr. Jason Robinson, Illinois Natural History Survey Title: Sometimes when your experiment fails, you win Abstract: Observations of bumble bee nesting are few, relative to the number of observations of foraging workers. The colony demographics of bumble bee colonies, particularly in the spring when foundress queens are actively foraging for pollen and nectar resources, are mysterious. I set out to systematically assess the nesting preferences of bumble bees at Nachusa by confronting spring foundresses with choices about woodland, edge or prairie habitat, the types of voids or cavities, whether the chemical scent of rodent activity, and the presence of insulating dried plant materials influence the likelihood of nesting. Upon successful nest establishment, I sought to individually tag workers during repeated night-time nest censuses (measuring rates of production and mortality) and measure the minimum foraging distances of individual workers by netting surveys of foraging bumble bees, and the production of reproductives by each colony. The best laid plans of ecologists often go awry; none of my 54 nesting structures were used by bumble bees in the spring and summer of 2025. After conference with the Friends of Nachusa, I used the funds set aside for my travel to Nachusa to continue this work to instead attend a workshop on identifying the Midwestern bee genera, given by Dr. Zach Portman, at the University of Minnesota. In the future, I plan to return to Nachusa to investigate similar questions with more cooperative species of bees. Presenter: Max Scheel, Notre Dame University Title: Quantifying vegetation structural complexity in restored tallgrass prairie using airborne LiDAR Abstract: A central goal of ecological restoration is to restore community composition, ecological function, and vegetation structure. In restored tallgrass prairies, research efforts have focused on understanding the management interventions that foster the recovery of community composition (e.g., biodiversity) and ecosystem functioning (e.g., productivity). Efforts to quantify restoration of vegetation structural complexity (VSC) have been comparatively limited in grassland ecosystems, largely because it can be difficult to measure at management-relevant scales and resolutions. Although VSC has been repeatedly shown to enhance ecosystem function and support biodiversity in forests, only recently have advances in airborne light detection and ranging (LiDAR) facilitated its measurement in grassy ecosystems. In 2025, we used helicopter-borne LiDAR to quantify VSC at high resolutions (>100 points/m2) across the entirety of Nachusa Grasslands. In the coming year, we will use these data to (i) assess the interactive effects of management intervention (bison grazing) and time-since-restoration on VSC, and (ii) investigate the relationship between biodiversity and VSC in restored tallgrass prairies. Conceptually, we suggest that community composition, ecological function, and VSC can be considered as three legs supporting the stool that is successful restoration. Therefore, we hope that sharing this dataset will encourage future collaborations that leverage these large-scale, high-resolution VSC data to investigate the interactions among these three factors in tallgrass prairie restorations. Presenter: Mary Vieregg, Nachusa RiverWatch team leader, Title: Illinois RiverWatch at Nachusa Grasslands: 2014-2025 Abstract: Since 2014, a cadre of trained Nachusa volunteers have searched annually for macroinvertebrates in the preserve’s streams. Following the protocol established by Illinois RiverWatch operating under the auspices of the National Great Rivers Research and Education Center, these community scientists have doggedly and consistently collected and recorded both habitat data (canopy cover, water temperature, substrate composition, algal growth, etc.) and biological data (the presence or absence of indicator macroinvertebrate indicator organisms). The collected data reflects both short-term and long-term changes in the streams’ health. Short-term changes can be caused by temporary phenomena such as beaver activity and weather conditions (such as drought and flooding). With several years’ data, however, long-term trends in stream health resulting from management decisions, climate change, and watershed modifications both within the preserve and beyond its borders can sometimes be discerned. Teasing apart the exact causes for these long-term changes can be difficult but it’s important to know what changes are happening. This poster illustrates what short-term and long-term changes have been recorded over the past twelve years of monitoring Nachusa’s streams. Presenter: Cindy Crosby, Nachusa Odonate monitoring team leader Title: Ode to Odonates Abstract: Since 2013, citizen science volunteers have collected data on Odonata at Nachusa Grasslands, establishing a baseline inventory of the species found here. From a single monitor in 2013, we now have a team of around 15 volunteers each season. To date, we have identified approximately 30 dragonfly species and 25 damselfly species on our site. Among our more unusual species for our region at Nachusa are the River Jewelwing damselfly (Calopteryx aequabilis), Springwater Dancer damselfly (Argia funebris), River Bluet damselfly (Enallagma anna), Eastern Ringtail dragonfly (Erpetogomphus designatus), and Lance-tipped Darner dragonfly (Aeshna constricta). In 2023, a nymph sampling and identification program was added to the effort to further understand what species are reproducing in our waters. As we track species' populations each season from early March to late October at Nachusa Grasslands, we gain a greater understanding of the influence of management, climate change, and other natural and human-made disturbances on these insects. Our data is added to that of other citizen science projects in Illinois through the Illinois Odonate Survey, managed by Peggy Notebaert Nature Museum. It is also submitted to Odonata Central, dedicated to understanding dragonfly and damselfly biodiversity in the Western Hemisphere. Our data at Odonata Central is then available as part of global efforts of scientists working with these insects. As we enter our 13th season of data collection, we continue to find species new to Nachusa Grasslands. Presenter: Jaron Cook, The Nature Conservancy; Amy Brewer, Dave Brewer, Nachusa Grasslands community scientists, Tony DeValle, Forest Preserve District of DeKalb County Title: 35 Years of Birds at Nachusa Grasslands: A Dynamic Landscape and a Resilient Community Abstract: Tallgrass prairie communities are often in flux as they respond to disturbances like fire, grazing, woody encroachment, and beaver damming. In spite of prairies' ever-shifting composition and structure, many of the birds that call this region home specialize in particular grassland states—from sparse, grazed grass, to shrubby thickets, to dense, wet meadows. The landscape that makes up the Nachusa Grasslands is no exception, having undergone enormous change as agricultural fields and dense woods have been restored to prairies and savannas. To better understand how the bird community has tracked with this change through time, we aggregated point count data from 1991 – 2025 collected under a unified protocol from 12 points in 21 survey years. The resulting visualizations tell a story of stability for most species, with notable trends for certain species associated with wetlands and forests. In addition to collecting annual point counts, future work will focus on quantifying environmental and ecological change over the sampling period to analyze potential impacts on the bird community. SPECIAL PREVIEW
Life Unearthed with Ariel Waldman Episode 5 Prairies: Life in Water Filmmaker Ariel Waldman and collaborator Dr. Wes Swingley spent time at Nachusa Grasslands in 2024 filming a documentary about biodiversity on the prairie. The series Life Unearthed with Ariel Waldman will premier on PBS this April, including 3 episodes about the prairie. We’ll preview Episode 5, Prairies: Life in Water, which includes our own RiverWatch team! A time for questions with Ariel and Wes will follow. Watch the trailer for the entire series. |