Genetic exchange, or gene flow, between disparate populations is a critical component of imperiled species conservation. Gene flow can be improved by management actions that facilitate species’ ability to travel between population strongholds, but only if those movement pathways are known and intentionally targeted for management actions.
For more than a decade, sage grouse conservation has largely focused on conserving and maintaining Priority Areas for Conservation, or PACs, that serve as population, habitat, and genetic strongholds for sage grouse. While this approach works to conserve populations that fall within those PACs, it has yet to incorporate natural genetic exchange between populations.
New research, led by Todd Cross, has added this critical missing piece to sage grouse conservation by spatially mapping connectivity pathways between existing sage grouse PACs. These maps provide managers and practitioners with valuable insight into where to invest conservation resources that best conserve genetic exchange among sage grouse populations within PACs.
Primary goals of this research were to ingrain connectivity into existing strategies by delineating landscapes vital to maintaining connectivity within and among PACs, and by developing spatial action maps to alleviate impedances to connectivity. According to co-author and Working Lands for Wildlife science advisor David Naugle, the significant reservoirs of genetic diversity already conserved within PACs makes adding in connectivity “more like giving the strategy an oil change instead of a new transmission.” David adds that “With these actions maps, the opportunities to intentionally conserve the ties that bind the sagebrush ecosystem are unprecedented.”
When combined with PAC-based conservation design and threat-based management, this approach can form the foundation for comprehensive conservation planning to complement more traditional reserve designs. Action maps developed with this approach can highlight areas where management efforts such as removing encroaching conifer trees or limiting land use conversion through targeted conservation easements can conserve pathways for genetic exchange between PACs.
The USDA-NRCS’s Framework for Conservation Action in the Sagebrush Biome provides an avenue for managing woodland expansion and for reducing cultivation and subdivision risks on western grazing lands.
Cross T.B., J.D. Tack, D.E. Naugle, M.K. Schwartz, K.E. Doherty, S.J. Oyler-McCance, R.D. Pritchert, and B.C. Fedy. 2023. The ties that bind the sagebrush biome: integrating genetic connectivity into range-wide conservation of greater sage-grouse. Royal Society Open Science 10:220437.
Conserving genetic connectivity is fundamental to species persistence, yet rarely is made actionable into spatial planning for imperiled species. Climate change and habitat degradation have added urgency to embrace connectivity into networks of protected areas.
Our two-step process integrates a network model with a functional connectivity model, to identify population centers important to maintaining genetic connectivity then to delineate those pathways most likely to facilitate connectivity thereamong for the greater sage-grouse (Centrocercus urophasianus), a species of conservation concern ranging across eleven western US states and into two Canadian provinces.
This replicable process yielded spatial action maps, able to be prioritized by importance to maintaining range-wide genetic connectivity. We used these maps to investigate the efficacy of 3.2 million ha designated as priority areas for conservation (PACs) to encompass functional connectivity.
We discovered that PACs encompassed 41.1% of cumulative functional connectivity—twice the amount of connectivity as random—and disproportionately encompassed the highest-connectivity landscapes. Comparing spatial action maps to impedances to connectivity such as cultivation and woodland expansion allows both planning for future management and tracking outcomes from past efforts.