Speyeria idalia populations have declined as much as 95 percent over the last three decades. Here we critically evaluate prairie habitat components along the Platte River in central Nebraska that S. idalia populations require in an effort to better inform conservation efforts. We utilized S. idalia count data from biological monitoring transects where vegetation, soils, land management, and flooding frequency data were also collected to describe the habitat constituents associated with S. idalia presence. We utilize comparative statistics, Pearson’s correlation analysis, and random forest analysis to model S. idalia habitat on land owned and managed by a small conservation NGO. Our findings suggest that S. idalia occupies specific habitat niches with a preference for well-drained soils (Inavale series) dominated by facultative upland plants, most prominently Andropogon gerardii. S. idalia is positively associated with large connected tracts of relict prairie containing Viola sororia and very moderate management regimes that remove shrubby cover (negatively associated) and promote forb cover (positively associated), while providing ample recovery time on burned and grazed patches for litter development (positively associated). Random forest analysis describes the presence of V. sororia, percent forb cover, and habitat isolation as the top three habitat variables of importance in predicting the presence/absence of S. idalia. Our finding that habitat isolation is a major predictor of S. idalia absence suggests many populations may be both spatially and genetically isolated. S. idalia’s future demands the preservation of tallgrass prairie fragments under management regimes that promote healthy populations and habitat connectivity.

Brinley Buckley, E. M., C. R. Allen, M. Forsberg, M. Farrell, and A. J. Caven. 2017. Capturing change: the duality of time-lapse imagery to acquire data and depict ecological dynamics. Ecology and Society 22(3):30. https://doi.org/10.5751/ES-09268-220330

Baasch, D. M., P. D. Farrell, A. T. Pearse, D. A. Brandt, A. J. Caven, M. J. Harner, G. D. Wright, and K. L. Metzger. 2019. Diurnal habitat selection of migrating Whooping Crane in the Great Plains. Avian Conservation and Ecology 14(1):6. https://doi.org/10.5751/ACE-01317-140106

Over 80% of the Mid-Continent Sandhill Crane (Antigone canadensis) Population (MCP), estimated at over 660,000 individuals, stops in the Central Platte River Valley (CPRV) during spring migration from mid-February through mid-April. Research suggests that the MCP may be shifting its distribution spatially and temporally within the CPRV. From 2002 to 2017, we conducted weekly aerial surveys of Sandhill Cranes staging in the CPRV to examine temporal and spatial trends in their abundance and distribution. Then, we used winter temperature and drought severity measures from key wintering and early migratory stopover locations to assess the impacts of weather patterns on annual migration chronology in the CPRV. We also evaluated channel width and land cover characteristics using aerial imagery from 1938, 1998, and 2016 to assess the relationship between habitat change and the spatial distribution of the MCP in the CPRV. We used generalized linear models, cumulative link models, and Akaike's information criterion corrected for small sample sizes (AICc) to compare temporal and spatial models. Temperatures and drought conditions at wintering and migration locations that are heavily used by Greater Sandhill Cranes (A. c. tabida) best predicted migration chronology of the MCP to the CPRV. The spatial distribution of roosting Sandhill Cranes from 2015 to 2017 was best predicted by the proportion of width reduction in the main channel since 1938 (rather than its width in 2016) and the proportion of land cover as prairie-meadow habitat within 800 m of the Platte River. Our data suggest that Sandhill Cranes advanced their migration by an average of just over 1 day per year from 2002 to 2017, and that they continued to shift eastward, concentrating at eastern reaches of the CPRV. Climate change, land use change, and habitat loss have all likely contributed to Sandhill Cranes coming earlier and staying longer in fewer reaches of the CPRV, increasing their site use intensity. These historically unprecedented densities may present a disease risk to Sandhill Cranes and other waterbirds, including Whooping Cranes (Grus americana). Our models suggest that conservation actions may be maintaining Sandhill Crane densities in areas that would otherwise be declining in use. We suggest that management actions intended to mitigate trends in the distribution of Sandhill Cranes, including wet meadow restoration, may similarly benefit prairie- and braided river–endemic species of concern.

There are an estimated half-a-million Plains Bison (Bison bison) present in North America in commercial and conservation herds. Most bison are rounded up and “worked” annually for parasite control, veterinarian attention, and processing, making it important to understand the impacts of these operations. Research indicates bison generally experience higher levels of stress than cattle during similar handling processes. However, most methods for assessing stress-level during working are invasive, increase handling time, and paradoxically increase stress levels. We designed a behavioral index to assess bison stress level during handling and used it to evaluate various predictors of stress response in a semi-wild bison herd. We examined how sex, age, herd of origin, previous experience, calf rearing, and body condition influenced bison stress response during working operations from 2015 to 2017. Our results indicate that stress level decreased with age and previous experience being worked through a particular facility. Additionally, herd of origin influenced stress level, indicating that stress response may have a genetic or epigenetic component. Our study provides an easily applicable tool for monitoring bison stress levels.