Saguaro National Park BioBlitz

Saguaro National Park BioBlitz

National Geographic partners with the National Park Service to inventory species in America's national parks, with the help of students, scientists, and the public. In 2011, the team took to Tucson, Arizona to count organisms large and small in Saguaro National Park.


4 - 12+


Biology, Ecology

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The National Park Service is cataloguing plants and animals for its birthday.

An agency of the United States Department of the Interior, the National Park Service (NPS) oversees numerous national monuments, various conservation and historical properties, and a whopping 58 national parks.

In 2016, NPS will celebrate its 100th anniversary. For the decade leading up to that, NPS and the National Geographic Society are co-hosting a special bioblitz—a 24-hour species inventory—in a different national park each year. The first BioBlitz was held in 2007 at Rock Creek Park in Washington, D.C. That event was followed by species inventories in Santa Monica Mountains National Recreation Area in California, Indiana Dunes National Lakeshore, and Biscayne National Park near Miami, Florida. Saguaro National Park in Tucson, Arizona, was chosen as the site for 2011.

“The hosts strive to choose parks that represent the diversity of ecosystems found across the United States and that are close to urban areas, so that scientists, school children, educators, and the public can all participate in the event,” says Sean O’Connor of National Geographic Education.

Created in 1994, Saguaro National Park is one of NPS’s newer parks. It covers 370 square kilometers (more than 91,000 acres) in two districts that are separated by the city of Tucson. The Tucson Mountain District (Saguaro West) ranges in elevation from 664 to 1,429 meters (2,180 to 4,687 feet) and contains two distinct ecosystems. Rincon Mountain District (Saguaro East) ranges in elevation from 814 to 2,641 meters (2,670 to 8,666 feet) and contains six distinct ecosystems.

Base camp for the BioBlitz was Saguaro West’s Red Hills Visitor Center, but BioBlitz activities took place in both districts.

Inventory Teams

While the park is home to an estimated 1.6 million saguaro plants—a type of cactus—many other species are represented. For BioBlitz, teams of volunteer scientists, students, educators, and community members worked together to find as many amphibians, reptiles, birds, mammals, invertebrates, fungi, and non-vascular and vascular plants as possible.

As many as 5,000 people attended the event, which was held from October 21 to 22. Among them were 2,000 school-age youth and their teachers, including about 75 who took multi-day hikes deep into the park.

“It was great to see so many school children here,” said Constance Negley, a Tucson resident who volunteered because her home is on the border of Saguaro West. "The kids had fun and an informative desert experience."

Besides the special activities for students, there were dozens of group activities focusing on everything from microbes to mule deer. The events were led by scientists, some of whom work for NPS in other parks and jumped at the chance to visit Saguaro, in the Sonoran Desert.

“I saw this as a once-in-a-lifetime opportunity to study the Sonoran tortoise,” said Claire Crow, a wildlife biologist at Zion National Park in Utah. Located in the Mojave Desert with an elevation of more than 2,143 meters (7,000 feet), Zion is the highest place desert tortoises are found.

Crow wanted to know if there were differences between the Sonoran and Mojave species. She learned there are.

“In addition to some physical differences, the Sonoran tortoises do not burrow as deeply or have as many burrow chambers as the ones in Mojave,” she reported.

Just as the focus of the inventory groups varied, so did the sampling methods. Some teams used nets and cups to capture insects.

Some teams used sound. In Saguaro East, Tim Helentjaris led a nocturnal bird survey using a protocol developed for the Tucson Audubon Society.

“We listen passively for about five minutes. If we haven't heard anything by then, we play short stretches of selected owl calls to see if we can get them to respond,” he said. “If they come in closer, I have a spotlight we can use to try to get a better look.”

Other teams conducted visual encounter surveys. Taylor Edwards, a biologist from the University of Arizona, led a group looking for “herps” (amphibians and reptiles). “We are looking for different types and just want a count,” Edwards said.

Once an animal was spotted, Edwards made note of the species, as well as location and even air temperature, on the field datasheets provided to all team leaders. “In a more detailed study, we would not only look for species that are present, but also those that are absent even though we expect to see them,” he said.

Taking note of non-native species is also important in BioBlitz surveys. Highly flammable buffelgrass and fountain grass, native to Africa and Asia, are threats to the Sonoran Desert.

“Fire is not part of the ecology here,” said Tom Van Devender of the Sky Island Alliance during a general plant survey. “If the bases of the saguaros or any other native plants are burned, they will die.”

The potential damage caused by the invasive grasses is so great that a community group called the Sonoran Desert Weedwackers removes the grasses on a regular basis.

Biodiversity at Base Camp

While the numerous inventory teams were hard at work, the Biodiversity Festival was taking place at base camp. It featured music, dance, poetry, talks by leading scientists, live animal demonstrations, and examples of cultures indigenous to the Sonoran Desert.

One highlight was ceremonial dances by members of the Yaqui tribe. Officially recognized by the U.S. government in 1978, the Yaqui are native to northern Mexico and southern Arizona. They are the only tribe to have special indigenous peoples’ identification cards that allow them to freely cross the U.S./Mexico border.

The science tent at base camp was not only a hub for data collection and processing, but also featured a variety of exhibits, such as a decomposing saguaro. In addition, there were 40 interactive exhibitor booths that featured wildlife and environmental groups, such as Reptile and Amphibian Ecology International and the Sierra Club. Kids of all ages had the opportunity to participate in activities at the booths and earn course credit toward a degree in Biodiversity Science.

“I loved all of the booths,” said Julia Shaw, a student at Arizona State University in Tempe and member of the Central Arizona Chapter of the Society for Conservation Biology. “There was a great variety and everyone was so nice.”

Marena Sampson, also a member of the society, added, “It was really interesting to learn about different types of work being done by scientists. It helps us think about possible career paths.”

It will take awhile to complete the entire inventory from BioBlitz 2011. Not only is there a lot of data to analyze, but some of it is not even ready yet.

“It takes three days to a month to grow a fungus,” said Brett Baxter, a student at the University of Arizona and member of the Arnold Lab. Led by Dr. A. Elizabeth Arnold, the lab studies ecological and evolutionary aspects of fungi, and is at work cultivating and analyzing fungi from plant tissues collected at BioBlitz.

“We expect to submit our official inventory in January,” said Baxter.

NPS will use the final data for its records and ongoing monitoring efforts. While that is certainly beneficial, perhaps BioBlitz participants and the environment as a whole experienced the bigger benefit.

BioBlitzes are a fantastic way to get people out to their local parks and participating in ecological science and monitoring,” said National Geographic’s O’Connor. “It's important to engage the public and especially students and educators in this type of activity to build in them an interest and understanding of the parks, habitats, and ecosystems around them.”

Fast Fact

Get Involved
Dont limit your interest in biodiversity to BioBlitz.
Help document Earths biodiversity and share wildlife encounters through Project NOAH, a technology tool supported by the National Geographic Society.
Participate in a Junior Rangers program at a national park.
Connect with local conservation organizations to learn about local wildlife. For example, the Tucson Audubon Society offers beginner bird walks on a regular basis.
Volunteer with a local organization to help preserve and protect biological diversity.

Media Credits

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Kimberly Dumke
Jeannie Evers, Emdash Editing, Emdash Editing
Kara West
National Geographic Society
Last Updated

May 20, 2022

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