One of the bigger surprises for me to come out of the State of the Birds report is the poor state of aridlands birds. This was the portion of the report that I drafted and, though I am familiar with aridland conservation issues, the fact that this habitat and its birds seem to be faring worse that any other habitat type except grasslands was not something I was expecting. This shows the real value in these types of analyses: the uncovering of the unexpected.
Aridlands — as it is used in the new U.S. State of the Birds Report released yesterday — refers to an array of dry habitats in the United States…including all our deserts (Chihuahuan, Sonoran, Mojave, Great Basin); the vast areas of sagebrush found on the Colorado Plateau and in the Great Basin; “scrub-shrub” of the Edwards Plateau; and the chaparral of coastal California.
Aridlands harbor some of the most interesting and sought-after birds in the United States, including many that have only small portions of their geographic range in our country or are only found in these areas:
- Sagebrush is particularly unique to North America and harbors numerous species found only in this habitat type, including Gunnison and Greater Sage-Grouse, Sage Thrasher, and Sage and Brewer’s Sparrow.
- Birds restricted to our deserts are also a unique group, including relatively common species such as Verdin, Cactus Wren, and Curve-billed Thrasher, and others with much more restricted ranges, such as LeConte’s Thrasher and Abert’s Towhee.
- The coastal California chaparral has its own unique suite of species, such as Wrentit and Lawrence’s Goldfinch.
- The juniper woodlands of the Edwards Plateau are yet another distinct aridland habitat type with its own birds, including the federally endangered Golden-cheeked Warbler and Black-capped Vireo.
I think it is this high number of species restricted to these habitat types (and therefore very vulnerable to changes in the habitat) that accounts for the declining state of aridlands birds.
Unfortunately, some of the same characteristics that make this habitat so “bird-friendly” are also those that make them “human-friendly.” Some of the largest and fastest growing metropolitan areas in the country are located in aridlands (Los Angeles, Phoenix, Las Vegas, San Diego).
Add to this urban mix healthy doses of energy development, conversion to agriculture, invasive species, grazing and predicted huge impacts from climate change — and you’ve got a recipe for declining birds, which is exactly what we see.
While extensive efforts are underway to conserve aridlands by The Nature Conservancy and other groups, clearly more attention must be paid to this habitat type and its unique birds by the conservation community.
Examples of things we can do?
- Establish “smart growth” measures in aridlands urban areas.
- Implement environmentally-friendly agriculture and energy development on a wider scale.
- Control new and existing invasive species before they get established.
- Ensure that existing parks and protected areas in aridlands are connected to each other.
(Image: Cactus wren in Arizona. Credit: Charlie Ott.)