Bi-State sage grouse success, thanks to science
In April of this year, U.S. Department of the Interior Secretary Sally Jewell announced that the Bi-State sage grouse, a Distinct Population Segment of the Greater sage grouse, would not be listed for protection under the Endangered Species Act. U.S. Geological Survey (USGS) Wildlife Biologist Michael Casazza explained at Tuesday’s third SNARL Spring Lecture that the lack of listing actually represents a victory for conservation efforts.
Casazza explained that Bi-State sage grouse populations have remained stable in their native ranges throughout the Mono Basin and parts of Nevada because of management efforts crafted using years of scientific research. Research and management are the product of a collaboration between federal, state, and local agencies, non-profits, tribes, and ranchers, to keep the species off the endangered species list.
That’s not to say the Bi-State sage grouse hasn’t seen a dramatic reduction in its habitat and population over the last century and a half. Bi-State sage grouse range has diminished by 75 percent because of an expansion of pinyon-juniper woodland. Pinyon and juniper trees have taken over former sage brush habitat primarily because of fire suppression, which allows the trees to flourish.
Increased fragmentation caused by power lines, renewable energy development, urbanization, grazing, hunting, and recreation in the West, have also helped push the species close to the brink of extinction.
Casazza said he and other scientists have been collecting data on Bi-State sage grouse for the past 10 years.
“There are 14 study sites, and 58 people in the field right now,” Casazza said.
Scientists gather detailed habitat information, including nest and brood site selection, individual survival and mortality rates, and even install motion-sensor cameras to monitor nests for predators, and solar-powered GPS tracking devices on individual birds.
The overall goal of the USGS research has been to develop models for adaptive sage grouse management using biological data. Casazza said that goal has been achieved.
For instance, GPS data gathered on the birds’ migration tells researchers which habitats Bi-State sage grouse prefer, and how they react to pinyon-juniper woodlands, or even to fire events. Meanwhile video footage has helped scientist close in on the sage grouse’s biggest predator: the Common raven.
Casazza noted that sage grouse evolved with mammalian predators, and therefore fly directly from their nests to avoid leaving a scent trail. However, ravens spot this movement and follow it directly to the sage grouse eggs.
“Behavior learned over thousands of years doesn’t work so well for ravens,” Casazza said.
Given the knowledge scientists have about these threats to Bi-State sage grouse populations, they can create specific management strategies, such as removing certain areas of pinyon-juniper, controling raven populations through nest removal or authorized take, or creating maps of buffer distances around sage grouse leks (breeding grounds) for future energy development to avoid.
Casazza said these management strategies are superior to any he knows of for other threatened or endangered species in California. These strategies also represent a change in thinking since Casazza began field research in the 1990’s.
“In the 1990’s, some [research] would be used in management and some of it wouldn’t be,” he said. “Over the last 13 years, I’m really pleased; management and science have really come together to rely on one another.”
In 2012, the collaborative group that began conservation efforts to avoid the Bi-State sage grouse listing released a $45 million action plan for the next decade that includes nearly 80 habitat restoration projects. That plan “is based on science,” Casazza said. “I’m really confident that we’ve come up with a lot of good ideas to manage this population … A lot of other endangered species, [management] is not nearly this good … and not nearly this hopeful.”
