Sagebrush control has historically involved mechanical and chemical (2,4-D) treatments designed for total control and which detrimentally affect nontarget plant species, resulting in decreases in native wildlife abundance and diversity. Tebuthiuron, a potentially selective herbicide with thinning capabilities, was applied at various rates to big sagebrush plots near Ten Sleep, WY in 1979 and Hyatteville, WY in 1983. Plant and small mammal communities were evaluated in 1992 and 1993. Big sagebrush cover in untreated areas was 31 ± 1% in 1992 and 34 ± 1% in 1993 at Ten Sleep, and 44 ± 4% at Hyatteville (α = 0.10). Big sagebrush control increased as application rate increased. Productivity of herbaceous species (graminoids, forbs, or both) tended to be greatest at about 11 to 17% big sagebrush cover. In general, plant community diversity tended to be greatest where sagebrush was thinned to this level. Small mammal community diversity was least at both sites where big sagebrush cover was less than 5%, and was strongly correlated with plant community diversity at Ten Sleep (R2W = 0.99; 4 degrees of freedom). In addition, greater abundance of or better habitat quality for endemic, stenotypic (habitat specialist) species was associated with about 15% big sagebrush cover. This suggests (albeit retroductively) that biodiversity at both local (alpha) and global (epsilon) scales might be conserved by thinning big sagebrush with tebuthiuron.

Migratory pathways in North American prairies are critical for sustaining endemic biodiversity. Fragmentation and loss of habitat by an encroaching human footprint has extirpated and severely truncated formerly large movements by prairie wildlife populations. Greater sage-grouse Centrocercus urophasianus, a Near Threatened landscape species requiring vast tracts of intact sagebrush Artemisia spp., exhibit varied migratory strategies across their range in response to the spatial composition of available habitats. We unexpectedly documented the longest migratory event ever observed in sage-grouse (> 120 km one way) in 2007–2009 while studying demography of a population at the north-east edge of their range. Movements that encompassed 6,687 km2 included individuals using distinct spring and summer ranges and then freely intermixing on the winter range in what is probably an obligate, annual event. The fate of greater sage-grouse in Canada is in part dependent on habitat conservation in the USA because this population spans an international border. Expanding agricultural tillage and development of oil and gas fields threaten to sever connectivity for this imperilled population. Science can help delineate high priority conservation areas but the fate of landscapes ultimately depends on international partnerships implementing conservation at scales relevant to prairie wildlife.