Aridlands
Public Lands Support More than Half of the Distribution of Aridland Birds
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Noteworthy • Public lands are very important for the conservation of aridland bird species; more than half of U.S. aridlands are publicly owned. • Public lands are especially important for Gunnison Sage-Grouse, a candidate for listing under the Endangered Species Act, with 79% of its U.S. distribution on public lands. • Nearly 90% of the public lands on which aridland birds occur are protected against conversion to agriculture and urban development to some degree. • However, the majority of these lands permit activities known to degrade habitats for birds, including energy development, grazing, mining, and logging, so active management is needed to protect vulnerable species. |
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| Image: Sagebrush habitat in Wyoming by Gerrit Vyn |
Aridland Birds on Public Lands
Aridlands include some of our country’s most unique habitats: all of
our deserts, sagebrush, chaparral, and other habitats characterized by
a lack of precipitation and a highly variable climate. Thirty-nine
percent of aridland bird species are of conservation concern and more
than 75% of aridland species are declining. About 18% of the U.S. is
aridlands, 56% of which is publicly owned. An average of 51% percent of
the U.S. distribution of 36 obligate aridland species is on publicly
owned lands during the breeding season and 54% during winter.
Gunnison Sage-Grouse, a candidate for listing under the Endangered Species Act, is more dependent on public lands than any other aridland species, with 79% of its distribution on public lands. Sage Sparrow and Le Conte’s Thrasher also have more than 75% of their distribution on public lands during the breeding season. In contrast, the endangered Black-capped Vireo has just over 7% of its distribution on public lands.
Four land managers (BLM, USFS, states, and NPS) are responsible for
more than 90% of the aridland bird species found on public lands during
the breeding season, highlighting the vital role these agencies play in
bird conservation. BLM lands are particularly important for sagebrush
birds, supporting more than two-thirds of the U.S. distributions of
Sage Thrasher, Sage Sparrow, and Brewer’s Sparrow during the breeding
season. USFS lands are important for many species, especially Wrentit
in coastal chaparral, with 63% of the breeding distribution on public
lands. State lands are important for Rufous-winged Sparrow, with more
than 50% of the species’ distribution on public lands. NPS lands are
important for some desert species, such as Lucifer Hummingbird,
California Condor, and Bendire’s Thrasher. DoD lands generally do not
support a large proportion of the distribution of aridland species but
are extremely important for California Gnatcatcher, with almost 46% of
the species’ distribution on public lands.
Nearly 90% of public lands on which aridland birds occur are protected
to some degree from major threats such as conversion to agriculture and
urban development. For lands managed under multiple-use mandates,
energy development, mineral exploration and production, livestock
grazing, and other uses are permitted but need to be analyzed for their
ability to support wildlife conservation. Most management plans that
focus on natural ecosystems in public aridlands allow for fire and
other natural processes that are essential for the long-term survival
of many bird species.
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| Percentage of the U.S. distribution of 36 aridland-breeding bird species on public vs. nonpublic lands (left). Breakdown of bird distribution on public lands shown for each public agency (right). |
Conservation Successes
Almost 46% of the distribution of the California Gnatcatcher
on public lands is found on DoD lands such as Camp Pendleton. In the
past two decades, DoD has spent more than $9 million on conservation
for this threatened species. Although the USFWS has designated nearly
200,000 acres of for military lands already address gnatcatcher
conservation priorities and are excluded from critical habitat
designation. Therefore, military training lands provide a refuge for
the California Gnatcatcher without sacrificing training
activities.
BLM’s Carrizo Plain National Monument in California and nearby saltbush
scrublands provide the last strongholds in this region for Le Conte’s
Thrasher whose habitat has been largely converted to agriculture and
oil fields. In the Mojave Desert, the BLM has secured the two largest
habitat blocks as the Bendire’s Thrasher Area of Critical Environmental
Concern and is developing a management plan.
Captive-bred California Condors were released back into the wild in
California in 1992 and in Arizona in 2006. Six birds were transferred
from captive breeding facilities to an acclimation pen on top of the
Vermilion Cliffs and were released to the wild. Since then, program
personnel have released approximately six to ten birds per year. There
are now more than 70 condors in Arizona and Utah, mostly in Grand
Canyon National Park, Zion National Park, and Glen Canyon National
Recreation Area.
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| Greater Sage-Grouse by Gerrit Vyn |
Given the high proportion of aridland birds on public lands, management actions will be extremely important in maintaining these species nationally. However, only about 20% of these lands are protected to maintain natural habitats, suggesting that many of these publicly owned aridlands and their birds remain vulnerable to a variety of threats. Land uses that potentially degrade habitat for aridland birds are permitted on the great majority of public-use lands. These include energy development and associated infrastructure, off-road vehicular traffic, grazing, mining, and logging. Although many land uses can be compatible with aridland bird conservation, management plans for these vulnerable landscapes need to incorporate measures to ensure long-term healthy populations of aridland birds.
Key challenges that will require active attention and management by public land managers include control of invasive plant species; keeping fire and other forms of disturbance within normal limits; promoting natural patterns of plant succession; and helping birds and other biodiversity adapt in the face of climate and land-use change.

