Availability of lesser prairie-chicken nesting habitat impairs restoration success

Regional populations of lesser prairie-chickens (Tympanuchus pallidicinctus) have been declining irregularly since the early 1900s (Jensen et al. 2000). Populations in the Sand Sagebrush Prairie Ecoregion of Kansas and Colorado, USA, have been experiencing declines during the last 2 decades. Ecoregion-wide declines included the Cimarron and Comanche National Grasslands in southwestern Kansas and southeastern Colorado, respectively, from which lesser prairie-chickens were nearly extirpated by 2016. In 2014, the United States Department of Agriculture (USDA)-Forest Service created a vegetation management plan to restore lesser prairie-chicken nesting habitat on the National Grasslands. We used management plan recommendations to evaluate available nesting habitat on National Grasslands and surrounding areas for 394 transmitter-marked lesser prairie-chickens translocated to the Sand Sagebrush Prairie Ecoregion during 2016-2019. We found that a small proportion of vegetation measurements met the USDA-Forest Service's 100% visual obstruction guidelines of 25.4 to 38.1 cm (Cimarron: 5.3-21.8% of observations among cover types; Comanche: 1.5-3.0%), and grass species with a high value for nesting were rare (Cimarron: 0.5-20.1% of observations within each cover type; Comanche: 1.5-3.0%). Lesser prairie-chickens selected for 2 of the 10 National Grasslands' cover types (shrubland state and warm season shortgrass state) during breeding season movements, but only shrubland state was selected for during nesting. Our results indicate that nesting habitat for lesser prairie-chickens is limited on Cimarron and Comanche National Grasslands. As private grassland was also avoided during nesting, lesser prairie-chickens in Baca and Morton counties are currently primarily relying on Conservation Reserve Program (CRP) grasslands to meet nesting habitat thresholds (Morton, KS: 17.7% CRP; Baca, CO: 16.6% CRP), which may be insufficient to sustain a viable population. Due to the impermanence of CRP, efforts to sustain local populations are likely to depend on increased improved lesser prairie-chicken nesting habitat on National Grasslands. Grazing strategies such as rest-rotation and year-long deferments may provide opportunities to restore lesser prairie-chicken habitat on sand sagebrush prairie.