Proposed Delisting of GYE Grizzly Bears

On March 3, 2016 the US Fish and Wildlife Service proposed delisting the grizzly bear population in the Greater Yellowstone Ecosystem.

Question:  How do you KNOW when a grizzly bear population should be considered for delisting, anyway?

Answer:  You look in the Grizzly Bear Recovery Plan: it provides a “roadmap to recovery” using science-based Recovery Criteria.

For the grizzly bear population in the Greater Yellowstone Ecosystem, there are 3 Demographic Recovery Criteria that must be met before this population can be considered for delisting.

Have these 3 Demographic Recovery Criteria been met?  Let’s find out!

Demographic Recovery Criteria #1:  “Because 48 adult females with cubs of the year is equivalent to a population of approximately 500 total individuals (IGBC, p. 43), we are establishing a target number of 48 adult females of the year. This target number shall not go below 48 for any two consecutive years. For genetic reasons (Miller and Waits 2003, p. 4338) it is desirable that the total population of grizzly bears in the GYA be maintained above 400 bears. To assure that this goal is met and in order to adopt a conservative approach, the total population will be maintained at or above 500 grizzly bears. The estimate of 48 adult females with cubs of the year will be calculated by the IGBST based on model averaging described in the Supplement to the Reassessing Methods Document (IGBST 2006, pp.2-10).”

Bear Trust International has evaluated Demographic Recovery Criterion #1 using data from the Interagency Grizzly Bear Study Team. As of April 12, 2016, we had access to data through year 2014.  Data for year 2015 are still being processed and organized.  Check out the graph below and remember that Demographic Recovery Criterion #1 states that the grizzly bear population in the GYE cannot fall below 500 individuals for 2 consecutive years.  This graph shows that Demographic Recovery Criterion #1 was met in year 2007.

delisting-criterion-1_part-2

Also check out the graph showing data for the number of females with cubs of the year, which cannot go below 48 for 2 consecutive years.  This graph also demonstrates that Demographic Recovery Criterion #1 was met in year 2007.

Demographic Recovery Criteria #2: “Sixteen of 18 bear management units within the Recovery Zone must be occupied by females with young, with no two adjacent bear management units unoccupied, during a 6-year sum of observations. This criterion is important as it ensures that reproductive females occupy the majority of the Recovery Zone and are not concentrated in one portion of the ecosystem.”

There are two Rules that the Interagency Grizzly Bear Study Team use to evaluate Demographic  Recovery Criterion #2:

Rule 1: For 16 of the 18 Bear Management Units (BMU), there must be occupancy by females with young in at least 4 of the 6 years.

Rule 2: Two adjacent BMUs can be unoccupied during ONLY 1 of the 6 years.

Bear Trust International has evaluated Demographic Recovery Criterion #2 using data from the Interagency Grizzly Bear Study Team. Based on the data we evaluated, Rule 1 and Rule 2 of Demographic Recovery Criterion #2 have been met.  How do we know?  Read Rule 1 above and see if the data in the graph below meet Rule 1:

Occupancy

To evaluate Rule 2, check out the graph showing the results for Rule 2 of Demographic Recovery Criterion #2.  You will find that both graphs demonstrate that Demographic Recovery Criterion #2 has been met.

Demographic Recovery Criterion #3:  “For independent females (at least 2 years old), the current annual mortality limit, not to be exceeded in 2 consecutive years and including all sources of mortality, is 9 percent of the total number of independent females. For independent males (at least 2 years old), the current annual mortality limit not to be exceeded in 3 consecutive years and including all sources of mortality, is 15 percent of the total number of independent males. For dependent young (less than 2 years old), the current annual mortality limit, not to be exceeded in 3 consecutive years and including only known and probable human caused mortalities, is 9 percent of the total   number of dependent young.”

Bear Trust International has evaluated Demographic Recovery Criterion #3 using data from the Interagency Grizzly Bear Study Team and based on the data we evaluated, it is clear that all three components of Demographic Recovery Criterion #3 were met prior to year 2007.  Here’s the graph for Independent females.  Remember, the Demographic Recovery Criterion #3 states that the Estimated Total Mortality cannot be ABOVE the Annual Mortality Limit for 2 consecutive years for Independent Female grizzly bears:Independent Females

Check out the graphs for Independent Males and for Dependent Young grizzly bears in the Greater Yellowstone Ecosystem.  All 3 graphs demonstrate that Demographic Recovery Criterion #3 has been met.

It’s your turn.  Based on the scientific data, have all 3 Demographic Recovery Criteria for the grizzly bear population in the Greater Yellowstone Ecosystem been met?

Background Information about grizzly bears in the Lower 48 States: Prior to the 1800’s, grizzly bears ranged from Alaska to Mexico and as far east as the western shores of Hudson Bay. In the Lower 48 states alone, there was an estimated 50,000 grizzly bears. By 1975, less than 1,000 grizzly bears remained in the lower 48 states, occupying less than 2% of their former range. In 1975, the US Fish and Wildlife Service listed the grizzly bear in the lower 48 states as Threatened under the Endangered Species Act (ESA). At that point, grizzly bears in the lower 48 states were placed under federal protection.

In 1982, the first grizzly bear Recovery Plan was completed, which identified 6 Grizzly Bear Recovery Zones in the lower 48 states:
Recovery Zones1

In 1983, the Interagency Grizzly Bear Committee was formed to ensure the recovery of viable populations in the 6 Grizzly Bear Recovery Zones.  Thanks to ESA protection and a lot of work by the Interagency Grizzly Bear Committee and other, the grizzly bear population in the Greater Yellowstone Ecosystem was DELISTED in 2007.  In 2009, a federal court overturned the 2007 DELISTING and grizzly bears in the Greater Yellowstone Ecosystem were relisted as Threatened under the ESA.

On March 3, 2016 the US Fish and Wildlife Service proposed that the grizzly bear population in the Greater Yellowstone Ecosystem is DELISTED because this population has met all delisting criteria.  Grizzly bear populations in the other 5 Recovery Zones have not been proposed for delisting.

 Photo of grizzly bear:  J. Cummins/Bear Trust International

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