SCIENCE BRIEF: Study of sagebrush bird communities yields valuable tools for setting habitat restoration objectives and measuring restoration effectiveness

Camas National Wildlife Refuge (c) U.S. Fish and Wildlife Service

Camas National Wildlife Refuge protects over 4300 hectares of land in the high desert of eastern Idaho. Throughout the year, migratory and resident birds and other wildlife use the Refuge’s grasslands, wetlands, wet meadows, and sagebrush-steppe habitats. People visit the Refuge to watch wildlife, hunt, hike, and ski. In parts of the Refuge, native sagebrush plant communities are being overtaken by non-native Crested Wheatgrass, an invasive species that is degrading the imperiled sagebrush-steppe ecosystems that span the North American Great Basin. More than 350 wildlife species of conservation concern, including species identified by the U.S. Fish and Wildlife Service (USFWS) as Birds of Conservation Concern (BCC), are associated with this ecosystem. Therefore, restoring and protecting sagebrush habitats has become a national priority and is a priority for the Camas National Wildlife Refuge and other refuges in the Great Basin. Determining how to invest limited resources to best achieve this and other refuge goals, which include conserving species of concern, can be a challenge for Refuge staffs as well as and other interested conservation partners.

To help overcome this challenge, USFWS and Klamath Bird Observatory (KBO) collaborated to use bird monitoring data collected on the Refuge, which are stored in the centralized Avian Knowledge Network (AKN) database, and an associated decision support tool (DST) for a collaborative research project designed to inform sagebrush habitat management planning. This study was recently published in the Journal of Fish and Wildlife Management. In the paper, the research team set quantifiable, numerical restoration targets for sagebrush habitats and predicted future bird community response to restoration treatments. The study illustrates how datasets stored and accessible in AKN as well as DSTs allow scientists to help land management agencies maximize conservation investments through monitoring, data sharing, and management-relevant research that informs their conservation planning and implementation.

In this study, researchers first used bird abundance data collected at the Refuge from 2012 to 2016 to characterize bird communities in three sagebrush-steppe habitat types that are being degraded by Crested Wheatgrass invasion. The research results identified specific birds as indicator species for the habitats studied at the Refuge. For example, two species of concern, Sage Thrasher and Sagebrush Sparrow, are indicators of sagebrush with native grass understory. In contrast, Mourning Dove preferred sagebrush with non-native understory and Grasshopper Sparrow abundance was associated with Crested Wheatgrass-dominated habitats.

Results from this study identified bird species that serve as indicators of both native and non-native sagebrush-steppe habitat characteristics. For example, Sage Thrasher and Sagebrush Sparrow, both identified as bird species of conservation concern by the U.S. Fish and Wildlife Service, show a strong preference for sagebrush habitats with native grass dominating the understory (Habitat Type ‘S’) as compared to sagebrush with a non-native grass understory (‘SC’) or Crested Wheatgrass dominated habitats (‘CR’). Therefore, these species can serve as ecological indicators of this important and threatened native sagebrush-steppe habitat characteristic that the Camas National Wildlife Refuge is working to protect and restore. (Photos (c) James Livaudais)

Next, the researchers used an interactive DST called Habitats and Populations Scenarios (HABPOPS) to explore potential population responses based on various restoration and management scenarios. According to Jaime Stephens, KBO Science Director and co-author on the paper, integrating monitoring results with the HABPOPS tool allowed the research team to set specific, measurable restoration targets using bird densities. Ms. Stephens said, “this information will help the Camas National Wildlife Refuge to guide their restoration design and evaluate their management outcomes.” The paper demonstrates how managers and conservationists can use bird-habitat associations and DSTs like the HABPOPS tool to design and evaluate ecosystem conservation actions at sites and across landscapes. Dr. John Alexander, KBO Executive Director and co-author on the paper, further suggests that this multi-species approach adds a novel and robust alternative to single-species management approaches traditionally used for conservation design and monitoring.

In the recently published paper, the research team demonstrates how Refuge data that identifies suites of indicators and the HABPOPS tool are used to meet conservation design objectives that have been prioritized for large-scale, multi-partner efforts to restore and protect sagebrush-steppe habitats in the United States. Land managers can use this approach to consider cost-benefit tradeoffs associated with their conservation efforts. Results suggested that restoration of Crested Wheatgrass near-monocultures back to sagebrush will improve habitat value for much of the bird community whether or not the understory can be converted to primarily native grasses, or a mix of natives and non-natives. But, select species will likely benefit most from full restoration of a native herbaceous understory. That being said, grassland-obligate birds like Horned Lark and Grasshopper Sparrow were most abundant at crested wheatgrass-dominated sites and may not benefit from full-scale restoration back to shrubland; So, managers should understand potential trade-offs.

“This study of Service data by Klamath Bird Observatory helps everyone better understand pressing conservation issues at National Wildlife Refuges and other sagebrush-steppe ecosystems,” said Brian Wehausen, refuge manager at Camas NWR. “This study can help guide restoration actions and maximize the benefits from conservation efforts, including the eradication of invasive grasses while also achieving increased benefits for birds of conservation concern. The information aids the development of priorities through science-informed conservation design, restoration implementation, and ecological monitoring.”

To request a PDF of the journal article, contact:
Sarah Rockwell, Research Biologist, Klamath Bird Observatory, 541‐201-0866 ext.6#, smr@KlamathBird.org

Recommended Citation (Online Early):
Rockwell SM, Wehausen B, Johnson PR, Kristof A, Stephens JL, Alexander JD, Barnett JK. 2020. Sagebrush bird communities differ with varying levels of Crested Wheatgrass invasion. Journal of Fish and Wildlife Management X(X):xx-xx; e1944-687X. https://doi.org/10.3996/JFWM-20-035

The work in the referenced article was supported by the U.S. Fish and Wildlife Service, but the findings and conclusions are those of the author(s) and do not necessarily represent the views of the U.S. Fish and Wildlife Service.

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