Sage Grouse Translocation Reverses Population Decline

Published at Harvesting Nature, November 26th, 2021.

Think you’ve heard it all when it comes to greater sage grouse conservation? Think again. When an icon of the sagebrush ecosystem becomes imperiled, conservation dollars flow to the far corners of habitat and population research to find solutions to species sustainability and persistence.

Mary Meyerpeter and colleagues with the US Geological Survey and Idaho State University are currently studying translocation to stabilize or even grow two declining sage grouse populations on opposite fringes of their North American distribution. The “Bi-State” population on the California-Nevada border was selected as a small, isolated group facing low hatch success and overall decline. A North Dakota population was selected after a suffering a severe West Nile Virus outbreak, reduced the population.  

Wildlife translocation has been a tool in the scientific toolbox longer than the words “science” and “research” have been in existence, and with this tool comes many benefits to imperiled populations. Declining genetic diversity and abundance of reproductive individuals are two challenges recipient populations typically face that may be overcome by translocation. Precisely what Meyerpeter et al. had in mind, coupled with estimating the population-level effects of introducing new individuals to the imperiled populations, and removing individuals from the donor populations.    

From 2017 through 2019, the Bi-State population received 68 adults and 125 chicks from a nearby source population, while the North Dakota population received 137 adults and 66 chicks from an interior Wyoming population. The populations were monitored across the translocation period and continue to be monitored.

Photo by the US Fish and Wildlife Service

Preliminary study results suggest that translocation efforts have been successful for the recipient populations. The Bi-State population increased 160 percent with egg hatch success increasing from 31 percent to 86 percent. Similarly, the North Dakota population increased 188 percent compared to pre-translocation estimates.

The Bi-State donor population declined 31 percent following translocations, which may have been attributed to that population also being relatively small, among other potential factors. The Wyoming donor population showed no change.

Translocation results are considered preliminary until a monitoring period of up to five years has documented population responses, but the results appear promising. Additionally, successful translocation coupled with habitat restoration can perpetuate the species and play a role in range expansion into historic habitats.