Status of 2021 Oregon Greater Sage-Grouse Adaptive Management Triggers

United States Department of the Interior
BUREAU OF LAND MANAGEMENT
Oregon State Office
P.O. Box 2965
Portland, Oregon 97208

MAR 9, 2022

IN REPLY REFER TO:
6502 (OR-931) P

EMS TRANSMISSION 03/10/22
Information Bulletin No. OR-2022-020

To: Oregon District Managers (Burns, Lakeview, Prineville, Vale)
From: Deputy State Director, Oregon/Washington
Subject: Status of 2021 Oregon Greater Sage-Grouse Adaptive Management Triggers

Purpose

This information bulletin (IB) transmits the results of the Oregon Greater Sage-grouse (sage-grouse) adaptive management thresholds and triggers evaluation for calendar year 2021. This IB summarizes the thresholds and where they were exceeded, which adaptive management triggers were activated or reversed, the required responses where a hard trigger was activated, and a summary of the causal factor analysis process and outcomes.

Background

The Oregon Department of Fish and Wildlife (ODFW) organized and named its sage-grouse core areas into 20 priority areas for conservation (PAC). The Oregon PACs encompass all Bureau of Land Management (BLM) priority habitat management areas (PHMA) and contain the most productive habitat for approximately 90 percent of the state’s breeding populations of sage-grouse within 38 percent of the species’ current range statewide. These areas have the highest conservation value to maintaining sustainable sage-grouse populations in Oregon. The Adaptive Management Strategy in Appendix J of the BLM’s Oregon Greater Sage-Grouse Approved Resource Management Plan Amendment (ARMPA) identifies hard and soft thresholds (triggers) for habitat and populations within the PACs. Exceeding (tripping) a hard threshold triggers the BLM to implement immediate and more restrictive plan-level actions to address sage-grouse conservation objectives. Soft triggers indicate that the BLM may need to implement management changes at the project level to reduce the likelihood of further declines tripping a hard trigger.

The Adaptive Management Strategy outlines the process, revised in 2020, the BLM Oregon/Washington (OR/WA) used in cooperation with the ODFW and the U.S. Fish and Wildlife Service (FWS) to determine the annual status of sage-grouse adaptive management triggers. The BLM met with ODFW and FWS to finalize the 2021 population trigger calculations on December 2, 2021. The BLM OR/WA State Office notified Vale, Burns, Lakeview, and Prineville Districts on December 21, 2021, that nine PACs had tripped a population and/or habitat trigger, including six hard trigger PACs and three soft trigger PACs (Attachment 1). Upon further analysis, the Lakeview District was informed on February 16, 2022, that the Tucker Hill PAC had tripped a hard habitat trigger due to a fire during September 2021. With this IB, the required hard trigger responses listed on page J-8 of the ARMPA go into effect in seven PACs and will remain until either a plan amendment makes a change or the BLM’s annual review of the relevant conditions listed in the Adaptive Management Strategy indicate the trigger has reversed.

Habitat Trigger

Habitat triggers are calculated from the proportion of all capable habitat acres within a PAC that are in existing (current) habitat. Capable habitat includes areas that either currently support vegetation cover appropriate for sage-grouse use (i.e., ≥5 percent cover of sagebrush species and <5 percent tree cover) or are predicted to support these vegetation conditions with treatments and/or natural plant succession. The BLM used two datasets from the Integrated Landscape Assessment Project developed by the Institute for Natural Resources to identify capable habitat and current habitat. Oregon PACs are mostly (89 to 99 percent) capable habitat. Current habitat that has burned with moderate to high soil burn severity classes, based on Burned Area Reflectance Classification (BARC) maps, is considered habitat loss. Unburned to low fire severity classes are used to represent unburned islands of sagebrush within the fire perimeter. 

Current habitat was below the soft trigger threshold (i.e., <65 percent current habitat) in the Cow Lakes and Trout Creek PACs in 2021 (Table 1). Both PACs were below the habitat threshold prior to the 2015 ARMPA. The historic Vale Seeding Project and multiple wildfires removed sagebrush from large sections of the Cow Lakes PAC. Seventy-two percent of the Trout Creeks PAC has burned at least once since 1975, with many acres burned multiple times. Four additional PACs with 65 to 70 percent current habitat are identified in Table 1. While these PACs have not tripped a habitat trigger, they are at risk of doing so with one large wildfire event. 

Fires burned approximately 13,101 acres within three PACs during 2021. The largest was the Cougar Peak fire that burned 11,848 habitat acres within the Tucker Hill PAC. Field-verified BARC maps indicate 6,259 acres of sage-grouse habitat was lost in areas with moderate to high fire severity. While this represents a 23 percent loss of habitat in a single year, the proportion of capable habitat that is current habitat (68.9 percent) remains above the soft habitat trigger threshold. Nonetheless, the hard habitat trigger was tripped in 2021 because more than 5 percent of current habitat was lost in one year. This trigger will un-trip (reverse) in 2022 if the habitat remains above 65 percent and if any new fires burn less than 5 percent of current habitat inside the PAC.

Table 1. Oregon PACs that have tripped or are close to tripping (65 to 70 percent current habitat) a habitat trigger in 2021.

PAC Name	Total PAC Acres	Capable Habitat Acres	Acres of Habitat Loss 2013-20211	Current Habitat Acres	Treatment Acres2 2012-2021	Percent Current Habitat	2021 Trigger Status
Bully Creek	279,855	264,572	14,587	178,808	80,445	67.6	none
Burns	35,769	32,364	0	22,125	2,075	68.4	none
Cow Lakes	249,733	240,158	430	148,663	17,720	61.9	soft
Folly Farm- Saddle Butte	251,558	232,381	1,109	158,134	24,809	68.0	none
Steens	185,730	166,065	387	107,987	45,812	65.0	none
Trout Creeks	393,473	378,221	9	222,220	69,268	58.8	soft
Tucker Hill	31,531	30,401	6,259	20,955	12,193	68.9	hard3

¹Habitat burned with moderate or high severity fire.
²Acres are project footprints that in most cases include multiple treatments.
³Greater than 5 percent current habitat lost in one year (2021).

Since 2012, the BLM has implemented vegetation treatments on approximately 252,323 acres of BLM-administered lands within the seven PACs identified in Table 1. These acres are project footprints that, in most cases, include multiple treatments of the same site (e.g., cut, pile, and burn juniper). Additional treatments have occurred on private lands. Treatments have included juniper removal, seeding, sagebrush planting, and chemical spraying of invasive annual grasses. In 2021, the BLM implemented habitat treatments on approximately 21,368 acres within the Bully Creek, Steens, and Trout Creeks PACs. Most treatments (18,619 acres) were chemical spraying. In the Tucker Hill PAC, approximately 10,000 acres treated since 2012 (mostly chemical spraying) were unburned in the 2021 Cougar Fire. Treatment acres can be added to current habitat acres once a BLM field office has verified the treated area currently supports ≥5 percent cover of sagebrush species and <5 percent tree cover. For example, juniper removal within the Steens PAC restored over 45,000 acres of sagebrush habitat, thereby preventing current habitat from falling below the soft habitat trigger threshold.

Population Trigger

The BLM sage-grouse population triggers are based on a combination of actual and estimated maximum counts of males attending complexes of closely allied leks within 1 mile of each other, between which male birds may move. Annually, the ODFW provides lek count data and works with the BLM to estimate the number of males in the 16 PACs containing an adequate number of leks to provide a reliable population estimate. The BLM established PAC population thresholds in the 2015 ARMPA based on year-to-year variation of the mean population estimate for the previous 16 to 20 years. The BLM reset population trigger thresholds in 2020 in accordance with direction contained in the Oregon BLM Adaptive Management Strategy to update the thresholds five years after issuing the ARMPA.

Sage-grouse population estimates based on actual and projected counts of males attending leks contain multiple assumptions regarding lek formation and extinction rates. Lek counts are an index of population size, and the actual number of sage-grouse in each PAC remains unknown. However, the BLM and ODFW have confidence in the accuracy of the population estimates due to the high proportion of known leks surveyed each year (68.8 percent in 2021) and consistency in monitoring methods applied over the previous 23 years.

The ODFW statewide sage-grouse population estimate increased 12.2 percent between 2020 and 2021. While 2021 marked the second consecutive year of statewide increase since the year with the lowest recorded population in Oregon’s history (2019), the increases were relatively small. Population triggers were tripped in eight PACs in 2021 (Table 2), including seven that had tripped a population trigger in 2020. The Paulina/12-Mile/Misery PAC population re-tripped a soft trigger that it had reversed (un-tripped) in 2017. Additionally, two PACs (Cow Lakes and Warners) moved from soft to hard population trigger.

Finally, the Solider Creek PAC population reversed the soft population trigger first tripped in 2020. Helicopter surveys by the ODFW discovered six new leks in the PAC and four new leks in adjacent habitat. Results from these lek searches may indicate that the large population decline observed in the Soldier Creek PAC since 2018 is partially due to lek movement, rather than a decline in the sage-grouse population in this area. With the observed increase in 2021 and the addition of at least six new leks, the sage-grouse population in the Soldier Creek PAC appears to be stable.

Table 2. Status of population triggers in Oregon PACs with an adequate number of leks to estimate male population size.

PAC Name	2021 Estimate (males)	2020- 2021 Percent Change	5-year Average (males)	Soft Threshold (males)	Hard Threshold (males)	2021 Trigger Status
Baker	116	-5.7	112	245	150	hard
Beatys	684	+11.0	768	887	464	soft
Brothers/N. Wagontire	113	-27.8	115	146	124	hard
Bully Creek	247	+5.4	281	178	129	none
Cow Lakes	156	+23.8	178	286	180	hard
Crowley	236	-11.9	263	184	120	none
Drewsey	183	+35.6	200	171	142	none
Dry Valley/Jack Mountain	72	+1.4	66	226	145	hard
Folly Farm-Saddle Butte	118	+53.2	118	57	24	none
Paulina/12- Mile/Misery Flat	296	-11.9	365	374	324	soft
Picture Rock	4	+100.0	4	23	17	hard
Pueblos/S. Steens	127	-17.3	151	99	18	none
Soldier Creek	274	+101.1	289	235	159	none
Steens	117	+4.7	136	114	76	none
Tucker Hill	49	+8.9	50	44	36	none
Warners	292	-10.6	346	496	375	hard

Population trends in the eight PACs that tripped a population trigger in 2021 are described below. Oregon PACs are located within mid-scale areas (shown in parentheses for each PAC) that were identified and mapped by the BLM and ODFW for use in the sage-grouse Habitat Assessment Framework. These mid-scale areas are also used for allocating annual funding to habitat conservation and restoration projects in high priority areas of the state.

Baker PAC (Baker) population has declined 87.6 percent since a population peak in 2003. The ODFW believes the population has stabilized since 2016. This small population is particularly vulnerable due to its geographic isolation from all other sage-grouse populations.

Beatys PAC (Warner-Meinzer) population has weathered two population cycles since 2003 and apparently hit the bottom of a third cycle in 2019 when it declined 50 percent. During 2020 and 2021, the population estimate increased by 34.9 and 11.0 percent, respectively. However, population growth since 2016 has not been sufficient to prevent the population estimate from dropping below the soft trigger threshold.

Brothers-North Wagontire PAC (Central Oregon) population first tripped the soft population trigger in 2016 and tripped the hard population trigger in 2018. Following a 60.8 percent increase in 2020, the population declined 27.8 percent in 2021.

Cow Lakes PAC (Owyhee River) population has been in decline since the 2015 Soda Fire burned leks and important seasonal habitat in Oregon and Idaho. While two new leks were found inside the PAC and the population estimate increased 23.8 percent during 2021, population declines during the previous five years lowered the estimate below the hard population trigger threshold for the first time since 2016.

Dry Valley/Jack Mountain PAC (Warner-Meinzer) population estimate has declined 87.6 percent since the Miller Homestead Fire burned over one-third of the sagebrush habitat and four lek complexes in 2012. The population declined below the soft trigger threshold in 2016 and tripped the hard trigger in 2017. During 2020, ODFW recorded the first population increase in four years. The population estimate was essentially unchanged in 2021.

Paulina-12 Mile/Misery Flat PAC (Central Oregon) population, often referred to simply as the Paulina PAC, first tripped the soft population trigger in 2016. In 2017, the 5-year average population estimate increased above the soft trigger threshold despite the annual estimate dropping by 6.9 percent. Since 2017, the annual estimate has declined 30.9 percent. In 2021, the estimate declined 11.9 percent, reflecting an overall decline across the Prineville District.

Picture Rock PAC (Warner-Meinzer) population has declined approximately 67 percent since 2015 and tripped the hard population trigger every year since 2017. The estimated number of males in the PAC increased from two in 2020 to four in 2021. Surveys for new leks have found more birds outside than inside this PAC.

Warners PAC (Warner-Meinzer) population estimate has decreased 31.5 percent since 2015. The population peaked in 2016, followed by three years of substantial annual declines (>10 percent) and two years of minor annual increases. Once the 5-year moving average estimate passed the 2016 peak, the population tripped the hard trigger. The 10.6 percent decline in 2021 was due, in part, to missing a survey of the largest lek in the PAC (Mule Lake East #1). However, including the estimated 69.62 males in the equation would not prevent the PAC from tripping the hard trigger.

Hard Trigger Responses

Responses to triggers that involve management changes or more restrictive plan level actions to address declines in habitat or population are outlined in the Adaptive Management Strategy in Appendix J of the ARMPA. All required hard trigger responses remain in place until the habitat or population trigger, whichever was tripped, rises above the trigger threshold. Exceptions to the hard trigger response can be allowed when the cause for a hard trigger is wildfire or insect outbreak, the disturbance cap has not been reached, and the BLM authorized project would have no direct or indirect impact on the sage-grouse population or habitat.

Causal Factor Analysis and Annual Review

When an adaptive management trigger is tripped, the BLM conducts an analysis of existing conditions and trends in the affected PAC to identify and address the apparent cause(s) for decline. Attachment 2 provides a brief overview of the Causal Factor Analysis (CFA) procedures and results. Causal factor reports have been completed for all Oregon PACs that tripped a trigger in 2021 except causal factors for the Paulina PAC, which will be analyzed in 2022. The Beatys PAC report prepared in 2019 is being revised to reflect population trends observed during 20202021. A CFA report will not be prepared for the Solider Creek PAC that tripped a soft annual population trigger in 2020 since the one-year trigger was reversed in 2021.

BLM field offices review their CFA report(s) annually to update them with current information on population trend, fire occurrence, habitat changes, vegetation treatments, and any other relevant information, management activities, and BLM authorizations implemented within the PAC. This information should be recorded on the CFA Annual Review Form, signed by the District Manager or Field Manager, and uploaded to the ORWA GRSG SharePoint in the Adaptive Management folder. If a BLM district determines the threats it analyzed in the CFA have not substantially changed, regardless of change in trigger status, then the CFA does not need to be revised. Annual reviews are due by the end of each calendar year.

Administrative or Mission Related: Mission

Districts with unions are reminded to notify their unions of this IB and satisfy any bargaining obligations before implementation. Your servicing Human Resources Office or Labor Relations Specialist can provide you with assistance in this matter.

Signed by
Todd M. Curtis
Acting Deputy State Director

Authenticated by
Diana Fisher
Data Services Section Chief

Attachments:

1. Map of PACs that tripped triggers in 2021 (1 p)
2. Causal Factor Analysis Process and Results (2 pp)

Distribution:
Lee Folliard
Kevin Ford
Kelli Van Norman
Glenn Frederick
Matt Obradovich
Jamie McCormack
Stephanie McKinney
Larry Ashton
Jami Ludwig
Paul Whitman
Megan McGuire
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