On a recent Saturday, teams of professional and citizen scientists gathered on each side of the U.S.-Mexico border. In a 24-hour period, the teams were tasked with photographing and identifying as many insects, animals and plants as they could find within a mile of the border.

The "Border BioBlitz" — a term coined by the National Parks Service — resulted in thousands of points of data, but it had a goal beyond collecting ecological observations.

"It's also about collaboration and putting forward an image that is more reflective of the beauty of the borderlands," said Benjamin Wilder, director of the University of Arizona's Desert Laboratory on Tumamoc Hill and of the Next Generation of Sonoran Desert Researchers, or N-Gen, the organization that spearheaded the BioBlitz. "A lot of discussion about the border carries this idea that the border is something that is inherently bad. But is it really this vile desolate area? Not at all."

Although some stretches run through harsh, sandy desert, the borderlands encompass many North American biomes, from urban coasts to scrubby chaparral to lush, spring-fed marshy areas. Across the diverse biomes are diverse ecosystems that are home to thousands of different species. 

"We're really interested in spreading awareness about the biodiversity of the borderlands," said Aaron Flesch, staff scientist for the UA School of Natural Resources and the Environment.

To spread awareness and foster a spirit of international collaboration between scientists and the public, Wilder and others in N-Gen developed the idea of the Border BioBlitz. They recruited scientists and conservationists, including Flesch, to lead teams of volunteers.

"We were a little apprehensive going into it," Wilder said.

But after the one-day event, the teams reported good news. From Tijuana and San Diego to McAllen near the coast of Texas, more than 150 people on 11 teams reported more than 2,500 observations. The overhead costs of the event were "unbelievably low," according to Wilder, because volunteers used a free platform to record their observations during the Blitz.

More importantly, the event was fun.

"Part of it was like a treasure hunt, chasing bird calls over brush and boulders," said Seyer Walla, a volunteer on Flesch's BioBlitz team. "Finding the vocalist and getting a positive identification at the end of the hunt was really satisfying."

BioBlitzers recorded their identifications using the iNaturalist app in the U.S. and Naturalista in Mexico. If internet capabilities were limited in the field, participants uploaded their observations to iNaturalist or Naturalista later. The platforms share a database of sounds, pictures and names of wildlife, insects and plants, and each observation includes the GPS coordinates where it was made. Registered naturalists ensure the accuracy of observations and can correct any misidentifications.

"If you're trying to develop a checklist of what species may occur in a region, the iNaturalist platform is absolutely fantastic," Wilder said.

Surprising Discovery at Organ Pipe

By the end of the day, close to 900 species of plants, bugs and animals of the borderlands had been identified. Many finds were predictable. Organ pipe cactus were found in Organ Pipe Cactus National Monument, and velvet mesquite — a Sonoran Desert native — heavily dotted the landscape of the San Luis Mountains.

But there also were surprises. Swimming with the indigenous fish and mud turtles of Organ Pipe was a red-eared slider turtle.

"That's non-native and that could be bad news for that pond," Wilder said. Although even one non-native animal can pose serious threats to indigenous species in an ecosystem, rapid identification and relocation of the offending animal can preserve the native flora and fauna. Knowing that the invasive slider turtle was in Organ Pipe was the first step in returning it to its native habitat in the Southeastern U.S.

A happier surprise was reported from the team that explored the rugged San Luis Mountains. Flesch found several green shrubs sprouting from the mountainside. Even with 20 years of research experience, he was not confident he recognized the plant. 

"It looks like a Buddleia," Flesch said. "This is a rare plant that has never been documented in this location."

After the BioBlitz, Flesch sent pictures and samples of the plants to other scientists. The species was confirmed: Buddleia sessiliflora, commonly called Rio Grande butterfly-bush or Tepozán. The plants Flesch found during the BioBlitz represent one of only seven populations of the butterfly-bush in Arizona.

Once all the observations are uploaded and validated, Wilder and N-Gen plan to use Geographic Information Systems to comprehensively map the data. These maps will then be uploaded to the N-Gen website, where anyone can view them or use them for further research and exploration.

Wilder hopes to make the Border BioBlitz an annual event. Monitoring the borderlands over a number of years could yield valuable information on how populations of plants, animals and insects are changing over time. The events will continue to emphasize collaboration.

"The BioBlitz is a way to bring people together, using science as a medium to transcend arbitrary divisions," said Michelle Capistrán, N-Gen associate director and leader of the team in Tijuana.

"Now is the time to proactively, piece by piece, continue building bridges where others aim to put walls," Wilder said.

To explore the biodiversity of the borderlands and view the observations of the Border BioBlitz, visit https://www.inaturalist.org/projects/border-bioblitz.