Managing Fragile Habitats for Avian Communities
An Ecosystem in Peril
Imagine a vast, silver-green sea of sagebrush stretching to the horizon, where the haunting calls of sage grouse echo at dawn and busy songbirds flit among the aromatic shrubs. This is the sagebrush ecosystem of the American West—one of the most extensive and least modified ecosystems in North America, on par with global treasures like the Amazon or Serengeti 6 .
Yet this seemingly endless landscape is in quiet crisis. Population declines among sagebrush-reliant birds mirror the larger deterioration of this vital biome 2 . These birds represent more than just species in trouble; they are vital components of an ecosystem that provides crucial services from seed dispersal to insect control 4 . The fate of these avian communities now depends on our ability to understand and manage the sagebrush sea they call home.
Hectares of sagebrush ecosystems in the western United States 1
Sagebrush ecosystems are not mere empty spaces between forests; they are complex habitats teeming with specialized life. The sagebrush itself—primarily plants of the genus Artemisia—provides food, shelter, and nesting sites for species found nowhere else 1 4 .
Beyond birds, this ecosystem supports a diverse cast of wildlife including pronghorn, sagebrush lizard, sagebrush vole, and pygmy rabbit 4 . This biological richness underscores the sagebrush ecosystem's value beyond its scenic beauty—it represents a vital piece of North America's natural heritage.
The bird communities of sagebrush habitats include both sagebrush obligates that depend entirely on these landscapes and grassland associates that utilize them as part of broader habitat needs 1 . Among the most vulnerable are the sagebrush obligates that cannot survive without healthy sagebrush ecosystems.
Partners in Flight has identified several of these species for their continental Watch List, placing them among the highest priority species for conservation action in North America 1 .
| Species | Dependence on Sagebrush | Conservation Status | Population Trend |
|---|---|---|---|
| Greater Sage-Grouse | Obligate | High priority | Declining, especially in degraded areas 1 6 |
| Gunnison Sage-Grouse | Obligate | High priority | Declining 1 |
| Sage Thrasher | Obligate | Conservation concern | 10x more abundant in core areas 2 6 |
| Brewer's Sparrow | Obligate | Watch List | 6x more abundant in core areas 1 2 6 |
| Sagebrush Sparrow | Obligate | Conservation concern | 3x more abundant in core areas 2 6 |
| Short-eared Owl | Grassland associate | Watch List | Declining 1 |
The deterioration of sagebrush ecosystems has been driven by multiple interconnected threats. Agricultural conversion has eliminated vast areas of native habitat, while overgrazing by domestic livestock has altered vegetation structure 1 . The invasion of exotic plants like cheatgrass has transformed fire regimes, leading to larger and more frequent wildfires that sagebrush cannot survive 1 5 . Meanwhile, expansion of pinyon and juniper woodlands into sagebrush habitats has fragmented the landscape and provided perches for predatory birds 1 2 .
Acres of intact sagebrush core areas lost each year 5
Of shrubland-dependent bird species declining in the U.S. 4
Of grassland bird species declining in the U.S. 4
These threats have collectively reduced and fragmented the sagebrush ecosystem to a shadow of its historical extent. The consequences for bird populations have been dire, with many species showing consistent population declines over the past 30 years 4 .
In response to these challenges, western partners have unified around a common vision for sagebrush conservation by developing the Sagebrush Conservation Design 2 5 . This innovative approach uses new remote sensing technologies to map the entire sagebrush biome and categorize it into three distinct categories:
The design identified that 87% of degradation across the biome is caused by invasive annual grasses and conifer encroachment, with land-use modification representing a severe, though more localized, threat 5 .
An underlying assumption of the Sagebrush Conservation Design has been that sagebrush-associated wildlife would benefit from actions targeting threats to the sagebrush biome. Researcher Alexander Kumar of the U.S. Fish and Wildlife Service led a team to explicitly test whether sagebrush ecological integrity (SEI), the metric used to quantify CSAs, is associated with sagebrush songbird abundance and population trends 2 .
The research team modeled the abundance of three species of sagebrush songbirds in core sagebrush areas compared to surrounding areas 2 6 . They found substantial increases in population counts associated with increased values of SEI across all three species examined 2 .
While there were some species-specific differences, generally sagebrush cover and tree cover were more important than grass cover in influencing bird populations 2 . This finding provides crucial guidance for conservationists, suggesting that management actions focused on maintaining sagebrush cover and preventing conifer encroachment will deliver the greatest benefits for sagebrush-obligate birds.
The Greater Sage-Grouse has long been considered a potential umbrella species for shrubsteppe avifauna—the idea being that by conserving habitat for these charismatic, area-sensitive birds, many other species would benefit 1 .
Research examined this question by looking at the extent to which sage grouse may serve as classic umbrella species 1 . Scientists found that sagebrush-associated bird species tended to occur together—with 83 pairwise correlations of relative abundance being significant, far more than the 8.55 that would be expected by chance 1 .
These findings suggest that conservation of sage-grouse populations in reasonable numbers well distributed across their historical ranges would indeed provide substantial benefits for many other bird species that co-occur with these grouse 1 .
Recent research led by Brian Prochazka of the USGS analyzed greater sage-grouse population trends on leks (mating grounds) across the biome from 1996–2021 6 . The team compared populations within the three different categories of landscapes defined by the Sagebrush Conservation Design, with striking results.
These dramatic differences demonstrate that conserving core sagebrush areas is of vital importance for maintaining the West's emblematic upland bird into the future 6 .
| Landscape Category | Population Trend | Conservation Implication |
|---|---|---|
| Core Sagebrush Areas | Stable | Vital strongholds for maintaining populations 6 |
| Growth Opportunity Areas | Declined by 22% | Need intervention to prevent further degradation 6 |
| Degraded Rangelands | Declined by 64% | Limited potential for cost-effective conservation 6 |
While the challenges facing sagebrush ecosystems can seem daunting, a success story along the California/Nevada border offers reason for hope. The Bi-State Distinct Population Segment of greater sage-grouse represents an isolated population at the southern extent of the species' range 6 .
For years, this population faced an uncertain future—until a collaborative conservation effort began in 2012. Researchers, led by Peter Coates of the USGS, analyzed data from 57 sage grouse leks before and after 85 different conservation actions, including treating weeds, restoring wet meadows, and removing conifers 6 .
The findings were striking: these cooperative conservation actions boosted the abundance of Bi-State sage grouse by an average of 4.4% annually 6 . This consistent growth resulted in a predicted population abundance increase of 37.4% since 2012, compared to what would have occurred if no conservation actions had taken place 6 .
This case study demonstrates that strategic, collaborative conservation based on sound science can reverse declines even for vulnerable populations. It provides a blueprint for how to implement the Sagebrush Conservation Design in practice.
Understanding and conserving sagebrush birds requires specialized approaches and technologies.
Tools like the Rangelands Analysis Platform enable researchers to map the entire sagebrush biome, categorize landscapes, and monitor changes over time 5 .
Scientists annually count male sage grouse at their traditional breeding grounds (leks) to track population trends 6 .
Standardized surveys where trained observers record all birds seen and heard at specific locations 3 .
A standardized way to quantify habitat quality based on five components: sagebrush cover, tree cover, perennial grass cover, annual grass cover, and human modification 2 .
Researchers use sophisticated models to analyze relationships between habitat conditions and bird populations 2 .
Multi-agency and stakeholder collaborations enable comprehensive conservation efforts across jurisdictional boundaries.
The story of birds in the sagebrush sea is at a critical juncture. On one hand, the challenges are significant—habitat loss and degradation continue at an alarming rate, and many bird populations are declining. On the other hand, science has given us both the understanding of what needs to be done and the tools to do it.
Of sagebrush habitat in public ownership 1
Strategic conservation can reverse declines for vulnerable populations
As one publication poignantly noted, "if we cannot successfully conserve sage-grouse and the sagebrush ecosystem in the U.S. given our theory, our knowledge, and our large blocks of public land, then one wonders how we can succeed for other species elsewhere" 1 .
The fate of the sagebrush sea—and the unique community of birds that depends on it—rests on our ability to translate science into conservation action. By defending core areas, restoring degraded lands, and working collaboratively across boundaries, we can ensure that future generations will still hear the dawn chorus of sagebrush birds in the vast, silver-green landscapes of the American West.