Why Intact Prairies Are Critical for Sharp-tailed Grouse Conservation
By L.B. McNew, Professor of Wildlife Habitat Ecology, Montana State University
We approached Oz from behind as he stood quivering is a sea of grass – with 10 generations of breeding instructing him to pounce and be still all at once. As I slowly passed him, I felt my own experience giving way to tense expectation and felt my heart thump in my ears as the sharpie erupted from the grass.
Hunters of sharp-tailed grouse everywhere know the heart-pounding moment when the year’s preparation culminates perfectly into one time-stopping moment in September. But unfortunately, this moment is becoming rarer – not because of declining hunter interest but because of decreasing habitat for our northernmost prairie grouse. Across the Northern Great Plains and Intermountain West, sharp-tailed grouse are losing the large, intact grasslands and shrublands they need to thrive – to the tune of hundreds of thousands of acres every year. Recent conservation efforts have leaned heavily on prescriptive habitat treatments including rotational management of livestock grazing, prescribed fire, and mechanical and chemical interventions. While these tools have their place, the best available science tells us they’re no substitute for unbroken, native prairie.
The Ecological Value of Intact Prairie
Large intact prairies (aka grasslands, shrublands, rangelands) support a rich mosaic of plant communities, habitats, and ecological processes that are difficult to replicate through restoration. For sharp-tailed grouse, intact prairies provide essential and diverse habitats serving multiple functions including - lekking, nesting and brood-rearing.
Because sharp-tailed grouse are non-migratory, all these habitat components need to occur within a relatively contiguous spatial extent. A single annual home range of a hen can exceed several thousand acres, so large connected habitats are a prerequisite for viable populations (Milligan et al. 2020c).
Scientific Evidence Supporting Intact Habitat Conservation
Sharp-tailed grouse historically occurred in native grassland and shrubland habitats from Kansas to Alaska, from California to Quebec. While initial small-scale plantings of grain during early Euro-American settlement likely provided winter food subsidies to sharp-tailed grouse, large-scale grassland/shrubland conversion to other land types, especially cultivation, resulted in extirpation of grouse from the southern and eastern extents of their historical range during the last century (Connelly et al. 1998, Schroeder et al. 2004).
Recent research underscores the importance of landscape-scale habitat integrity. Key insights include:
Lek Persistence: The leks of sharp-tailed grouse, like all prairie grouse, are more likely to persist in areas with high proportions of intact native grassland (Niemuth 2011, Burda et al. 2022). Fragmentation of native prairie reduces lek attendance and increases lek abandonment.
Nesting Success: Nest success (aka nest survival) contributes more to population size and stability than any other vital rate. Studies show that nest success is significantly higher in large, contiguous grasslands compared to smaller and fragmented grasslands (Manzer and Hannon 2005). Habitat edges associated with fragmented grasslands are often exploited by common nest predators of grouse (Crooks et al. 1999, Dijak et al. 2000).
Population Viability: Long-term population analyses indicate that sharp-tailed grouse are more resilient in intact landscapes, where they can move freely and access a range of seasonal habitats (Milligan et al. 2018, Runia et al. 2021).
Conservation Recommendations
The relative effects of habitat treatments like fire and grazing on the reproductive success and survival of sharp-tailed grouse depend on habitat conditions considered at broad spatial scales.
That means that the ‘best’ grazing management system for sharp-tailed grouse will vary across space and, importantly, a single grazing system should not be broadly prescribed. What is consistent across time and space is the species’ need for large contiguous prairie habitats.
Priority should be given to conserving large grassland/shrubland landscapes. A grazing prescription that provides perfect nesting cover on remnant grassland habitat will do little to improve population viability in areas where most of the landscape has been converted to cultivation or other types of human development. Rangeland management matters, but secondarily to native grassland conservation.
To ensure the long-term survival of sharp-tailed grouse and other grassland species, conservation organizations should:
1. Prioritize Protection of Intact Grasslands and Shrublands. Limited budgets should be prioritized to A) secure conservation easements and support landowners who maintain native prairie over incentivize prescriptive livestock grazing, and B) advocate for policies that conserve remaining native prairies.
2. Use Prescriptive Treatments Strategically. Apply prescriptive tools only where they complement existing intact habitat. In large areas (> 20 mi2) of contiguous prairie, prescriptive grazing management may be used to improve life-stage specific conditions, like nesting cover, for sharp-tailed grouse, but the appropriate prescription will depend on existing site conditions. For example, deferment of grazing may benefit nesting hens at sites during or after dry years, whereas short-term high-intensity grazing may reduce residual cover that exceeds recommendations for nest cover on productive sites under good precipitation. Although the science is pretty consistent on the optimal habitat conditions for nesting hens, for example, treatments needed to achieve them is highly variable across the range of sharp-tailed grouse (McNew et al. 2023). Regardless, land managers should always monitor outcomes to ensure treatments align with species-specific needs.
3. Promote Landscape-scale Planning. Collaborate with partners to maintain habitat connectivity across jurisdictions. Incorporate sharp-tailed grouse habitat models into land-use planning.