PHOENIX — An annual survey of the Mount Graham red squirrel recently revealed a slight decline in the number of the endangered squirrels in the Pinaleño Mountains in southeastern Arizona.
The survey conducted jointly by the Arizona Game and Fish Department, Coronado National Forest, U.S. Fish and Wildlife Service and the University of Arizona estimated 252 squirrels. The survey is a decrease of 11 squirrels from the 2015 estimate of 263.
“While we’d prefer to see squirrel populations continually grow, it’s not uncommon for them to fluctuate considerably from year to year,” said Tim Snow, AZGFD terrestrial wildlife specialist. “At this point, we aren’t immediately concerned with the lower squirrel numbers. We remain optimistic that our efforts are working to ensure the population has the best opportunity to flourish in the future.”
Helena, MT – Governor Steve Bullock issued an executive order today declaring a statewide natural resource emergency for Montana water bodies due to the detection of the larvae of invasive aquatic mussels at Tiber Reservoir and suspected detections at Canyon Ferry Reservoir and the Milk and Missouri rivers. The signing of the Executive Order triggers the deployment of an interagency rapid response team to respond to the emerging situation.
“Aquatic invasive species are a serious threat to Montana’s critical infrastructure and economy. The deployment of the multi-agency rapid response team will work quickly to identify and contain existing mussel populations, and prevent future introduction to other water ways,” Bullock said. “The potential economic, ecological and recreational impacts for Montana and our region must be addressed quickly and every effort must be taken to prevent the additional spread of this threat.”
Changes in human uses of the land have had a large impact on fire activity in California’s Sierra Nevada since 1600, according to new research
Forest fire activity in California's Sierra Nevada since 1600 has been influenced more by how humans used the land than by climate, according to new research led by University of Arizona and Penn State scientists.
For the years 1600 to 2015, the team found four periods, each lasting at least 55 years, where the frequency and extent of forest fires clearly differed from the time period before or after.
However, the shifts from one fire regime to another did not correspond to changes in temperature or moisture or other climate patterns until temperatures started rising in the 1980s.
"We were expecting to find climatic drivers," said lead co-author Valerie Trouet, a UA associate professor of dendrochronology. "We didn’t find them."
Instead, the team found the fire regimes corresponded to different types of human occupation and use of the land: the pre-settlement period to the Spanish colonial period; the colonial period to the California Gold Rush; the Gold Rush to the Smokey Bear/fire suppression period; and the Smokey Bear/fire suppression era to present.
"The fire regime shifts we see are linked to the land-use changes that took place at the same time," Trouet said.
"We knew about the Smokey Bear effect — there had been a dramatic shift in the fire regime all over the Western U.S. with fire suppression. We didn't know about these other earlier regimes," she said. "It turns out humans — through land-use change — have been influencing and modulating fire for much longer than we anticipated."
Finding that fire activity and human land use are closely linked means people can affect the severity and frequency of future forest fires through managing the fuel buildup and other land management practices — even in the face of rising temperatures from climate change, she said.
Trouet's co-authors are Alan H. Taylor of Penn State, Carl N. Skinner of the U.S. Forest Service in Redding, California, and Scott L. Stephens of the University of California, Berkeley.
Initially, the researchers set out to find which climate cycles, such as the El Niño/La Niña cycle or the longer Pacific Decadal Oscillation, governed the fire regime in California's Sierra Nevada.
The team combined the fire history recorded in tree rings from 29 sites all along the Sierra Nevada with a 20th-century record of annual area burned. The history spanned the years 1600 to 2015. However, when large shifts in the fire history were compared to past environmental records of temperature and moisture, the patterns didn't match.
Other researchers already had shown that in the Sierra, there was a relationship between forest fire activity and the amount of fuel buildup. Team members wondered whether human activity over the 415-year period had changed the amount of fuel available for fires.
By using a technique called regime shift analysis, the team found four distinct time periods that differed in forest fire activity. The first was 1600 to 1775. After 1775, fire activity doubled. Fire activity dropped to pre-1775 levels starting in 1866. Starting in 1905, fire activity was less frequent than any previous time period. In 1987, fire activity started increasing again.
However, the frequency of forest fires did not closely track climatic conditions, particularly after 1860.
The researchers reviewed historical documents and other evidence and found the shifting patterns of fire activity most closely followed big changes in human activity in the region.
Before the Spanish colonization of California, Native Americans regularly set small forest fires. The result was a mosaic of burned and unburned patches, which reduced the amount of fuel available to fires and limited the spread of any particular fire.
However, once the Spanish arrived in 1769, Native American populations rapidly declined because of disease and other causes. In addition, the Spanish government banned the use of fire. Without regular fires, fuels built up, leading to more and larger fires.
The influx of people to California during the Gold Rush that began in 1848 reduced fire activity. The large numbers of livestock brought by the immigrants grazed on the grasses and other plants that would otherwise have been fuel for forest fires.
In 1904, the U.S. government established a fire suppression policy on federal lands. After that, fire activity dropped to its lowest level since 1600.
Starting in the 1980s, as the climate warms, fire frequency and severity has increased again.
Fires now can be "bad" fires because of a century or more of fire suppression, according to lead co-author Taylor, a professor of geography at Penn State.
"It is important for people to understand that fires in the past were not necessarily the same as they are today," Taylor said. "They were mostly surface fires. Today we see more canopy-killing fires."
The study was supported by the Department of InteriorSouthwest Climate Science Center, which is managed by the USGS National Climate Change and Wildlife Science Center. The center is one of eight that provides scientific information to help natural resource managers and communities respond effectively to climate change.
This article was written by Mari N. Jensen, UA College of Science, and originally published on the University of Arizona website here.
U.S. Fish and Wildlife Service Issues Final Policy on Mitigating Impacts of Development to Further Conservation of Nation’s Wildlife and their Habitats
Policy provides a framework for more efficient and effective mitigation measures while facilitating review and approval of development projects
The U.S. Fish and Wildlife Service today announced a final revised Mitigation Policy that will guide its review of potential impacts of land and water development projects on America’s wildlife and their habitats. Through this policy, the Service will help others mitigate (avoid, minimize and compensate) for a project’s impacts to species and their habitats. This update of the Service’s longstanding Mitigation Policy, which has guided agency recommendations since 1981, will provide a broad and flexible framework to facilitate conservation that addresses the potential negative effects of development, while allowing economic activity to continue.
VALLEJO, Calif., Nov. 18, 2016 – The U.S. Department of Agriculture (USDA) announced today that the U.S. Forest Service has identified an additional 36 million dead trees across California since its last aerial survey in May 2016. This brings the total number of dead trees since 2010 to over 102 million on 7.7 million acres of California's drought stricken forests. In 2016 alone, 62 million trees have died, representing more than a 100 percent increase in dead trees across the state from 2015. Millions of additional trees are weakened and expected to die in the coming months and years.