We’re proud to release a new collaboration with Western National Parks Association, ‘Funding Research in our National Parks’. Shooting for this project took us to Saguaro National Park in Arizona, Chaco Canyon in New Mexico, Pinnacles National Park in Central California, University of Arizona and University of California Santa Cruz.
Since 1938, WNPA has funded scientific research to help advance the management, preservation, and interpretation of our national parks. They are committed to supporting meaningful inquiry in parks, helping shape the national park experience for every visitor. One of the key goals of their research program is interpretation—turning research findings into relevant narratives that engage, inform, and entertain.
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More on research from WNPA
The remains of an ancient culture, including ruins of the Great Houses of Chaco Canyon, lie silently in a remote canyon on the Colorado Plateau in northwestern New Mexico. Now part of Chaco Culture National Historical Park, these massive and mysterious communal structures, made primarily of stone interlaced with mud mortar, speak of a long-ago Southwest culture. The great houses, once covered by timbered roofs and ceilings made from thousands of large pine beams, took nearly three centuries to build.
Scientists have explored Chaco Canyon for more than 100 years, making it one of the best-known archaeological sites in the world. According to research scholar Stephen H. Lekson, “Its ruins represent a decisive time and place in the history of ‘Anasazi,’ or Ancestral Pueblo peoples.”* Who these ancestral peoples were and what they accomplished has been the subject of much study, including research sponsored by Western National Parks Association.
One of the pressing questions archaeologists face is how to place an ancient structure on a historical timeline. The rate of decay of radioactive substances is one way to determine the age of an object, but attempts using this method to date Chaco Canyon’s Great Houses produced vague results. Where ancient buildings incorporated wooden beams, like Chaco Canyon’s Great Houses, dendrochronology—the science of tree ring dating—can help us accurately place these structures in history.
What Tree Rings Can Tell Us
Dendrochronology (from dendron, meaning “tree limb,” and khronos, meaning “time”) can be used to date wooden objects based upon an analysis of tree rings. A tree’s annual rings can be seen in a horizontally-cross-sectioned trunk; each ring is a layer of wood produced by a single year’s growth. By comparing tree ring patterns in a timber core sample to the patterns in known samples, researchers can calculate exactly what year the tree was cut down.
Dendrochronolgy was established as a science in the early 20th century by A.E. Douglass, an astronomer who founded the University of Arizona Laboratory of Tree-Ring Research. In 2014, University of Arizona scientists Thomas Swetnam, Jeffrey Dean, and Christopher Guiterman were awarded a grant from Western National Parks Association to study the source of timbers from the Great Houses of Chaco Canyon. By comparing the age of timbers in the Great Houses to the age of trees from the upland areas and mountain ranges around Chaco Canyon, the scientists hope to determine the source of the Great House timbers.
The knowledge gained from this study will contribute to our understanding of ancient Pueblo culture and enhance the experience of visitors to Chaco Culture National Historical Park.
The California condor (Gymnogyps californianus) is an endangered New World vulture and the largest bird in North America. In the 1980s, the entire population of California condors was reduced to 22 birds. With the assistance of captive breeding programs, the condor was brought back from the brink of extinction. Captive-bred birds have been reintroduced to California, Arizona, Utah, and Baja California. There were more than 230 condors in the wild in 2013, but the bird’s recovery has been sluggish.
The extremely slow reproductive rate, usually one egg per clutch, and the fact that females don’t nest every year, prevents condor numbers from booming. Young condors are dependent upon their parents for as much as a year and can take 6 to 8 years to mature.
The Impact of Lead on Condor Reproduction
In addition to a slow reproductive rate, the condor’s susceptibility to lead poisoning caused by ingesting lead ammunition fragments, is a major impediment to establishing a viable wild population. Lead impairs the stress response, and elevated stress is known to interfere with avian reproduction.
In 2010, the Peregrine Fund reported that 72 percent of condors captured in Arizona had lead in their blood. Of this number, 34 birds were treated by chelation, a technique for removing heavy metals from the blood. To mitigate lead poisoning in reintroduced condors, each bird is recaptured two times a year and tested for blood lead levels. If a condor tests high for lead, a chelation treatment is warranted.
In 2014, Western National Parks Association awarded a grant to scientists from the University of California Santa Cruz to help fund a study of the stress response in chronically lead-exposed condors and the associated effects on reproductive success. This study is being conducted under the auspices of the condor program at Pinnacles National Park in central California where park officials are currently managing about 25 free-flying condors.
Graduate student Zeka Kuspa, working under the supervision of UC Santa Cruz Professor Donald Smith, along with toxicologist and Adjunct Professor Myra Finkelstein, is examining condor fecal samples for elevated stress hormones in captive condors over a 24-hour period following a routine capture and handling event. After establishing a baseline for stress hormones in the fecal samples of the recaptured birds, the scientists will compare their findings to stress hormone data from condors with high-lead blood levels.
The data collected by these scientists will increase our understanding of the effect of ingested lead on the stress response and reproductive success of this magnificent, endangered bird.
In September 2014, Kuspa presented her preliminary findings at a joint meeting of the American Ornithologists Union, the Cooper Ornithological Society, and the Society of Canadian Ornithologists. We look forward to the final report on this project.