On March 3, several teams of biologists, naturalists and proactive citizens set forth to document biodiversity at 11 sites along the border between the United States and Mexico, ranging from San Diego and Tijuana on the Pacific Coast, to Santa Ana National Wildlife Refuge in the lower Rio Grande Valley. These dedicated teams worked all day to document the biodiversity in the borderlands as part of the first annual Border BioBlitz.
The Border BioBlitz project was conceived by members of the Next Generation Sonoran Desert Researchers. “N-Gen” is a network of individuals and institutions committed to the rich social and ecological landscape that spans the Sonoran Desert, Baja California Peninsula, Gulf of California, and the U.S.-Mexico borderlands. With so much negativity surrounding the U.S.-Mexico border, the BioBlitz sought to shine a positive light on this dynamic and diverse place that so many people and wildlife call home.
In total, over 2,200 observations of 800 different species were made at 11 survey sites distributed along the nearly 2,000-mile border. Six of the 11 survey sites were located in Mexico.
BioBlitzing at Coronado National Memorial
Leaving my home in Tucson an hour before sunrise, I met up with Dr. Taylor Edwards, a population geneticist from the University of Arizona. Taylor and I first met ten years earlier while working with the Turner Endangered Species Fund at the Armendaris Ranch in New Mexico to rewild North America’s largest land reptile, the Bolson tortoise (Gopherus flavomarginatus), which occupies a small region in the Bolson de Mapimi in northern Mexico where the states of Chihuahua, Durango, and Coahuila converge.
The destination for our particular Border BioBlitz site was Coronado National Memorial, located at the southern foot of the Huachuca Mountains in southeast Arizona, nestled between the San Pedro River to the east and the Santa Cruz River to the west. These two rivers are unique in that they both flow south to north and cross the international boundary. In the case of the Santa Cruz River, it crosses the border twice, beginning its life in the United States in the San Rafael Valley, flowing south into Sonora, Mexico, then making a U-turn to re-cross the line again at Nogales on its 184-mile-long northward journey through Tucson toward its confluence with the Gila River. Like the Rio Grande and the Colorado, these are truly binational rivers, vital to life, and shared by both countries.
We knew the day was off to a good start when, less than five minutes after arriving at the Memorial, Taylor and I spotted a javelina right off the road. This pig-like animal, also known as the “collared peccary” (Pecari tajacu), is a commonly seen Borderlands resident that is equally at home in the tropical rain forests as it is in the Sonoran Desert. The javelina is widely distributed across Central and South America, including the entire Amazon Basin.
Early March is still winter for much of North America, but despite the frigid winter conditions of 68 degrees in southern Arizona, a group of 12 Border BioBlitz participants met at the Coronado National Memorial Visitor Center at 8 a.m. Saturday morning. The group was composed of botanists, computer programmers, retirees, and others. Over the course of the day, we managed to record 263 observations on our 4-mile trek from Coronado Peak back to the Visitor Center.
We used the iNaturalist app to record our observations, as did the rest of the 100+ people who participated in the Border BioBlitz across the U.S. and Mexico. iNaturalist is a digital database that records and stores crowd-sourced biodiversity information collected by observers using their smartphones. The observer takes a photograph of the taxon they find and enters their identification. The app automatically uploads the photos and all associated information about the location—most importantly the GPS location, which is recorded in latitude/longitude by the smartphone’s GPS chip. After the observation is uploaded, it is made live on the iNaturalist website and to those using the app.
At that point, members of the iNaturalist community (anybody using the app) help verify the species identifications. It is citizen science in real time. When two-thirds of the reviewers agree on a species ID, it is given “research grade” status. This must be taken with a grain of salt, of course, for not all iNaturalist users are taxonomists, and one or two photographs does not usually capture the full range of traits that a species exhibits. Nevertheless, iNaturalist is a powerful tool to help document biodiversity and foster an appreciation of nature by our citizenry.
Getting to the Heart of the Region
Before we began our survey, Zachary Palma, a National Park Service ranger, gave the BioBlitzers a presentation on the natural and cultural history of Coronado National Memorial. The Memorial was established to commemorate the expedition of Francisco Vázquez de Coronado, who arrived at this location in 1540 while coming south from Mexico in search of the Seven Cities of Cíbola, or the Seven Cities of Gold.
“The U.S.-Mexico border is not the outer limits of each country, but rather the heart of the region.” -Mikayla Mace
Zach also explained the biological significance of the Huachuca Mountains, and how they lie at the convergence of four great ecosystems: the southern end of the Rocky Mountains, the northern tip of the Sierra Madre, the Chihuahuan desert to the east, and the Sonoran desert to the west. These mountains are part of what are called the “Sky Islands,” an archipelago of tall mountain ranges that rise above the desert valleys below, providing refuge and habitat for a diverse array of plant and animal species that reach the distributional limits of their ranges. The 20 or so “sky islands” that straddle the U.S. and Mexico borderlands are home to jaguar, ocelot, elegant trogon, black bear and a subspecies of deer that we later saw toward the end of our day, the Coues whitetail deer (Odocoileus virginianus couesi).
While there is a 20-foot-high impermeable fence, built in 2007, that starts at the east end of the park and stretches 30 miles east towards Douglas, Arizona, there is no border wall or significant fencing at most of Coronado National Memorial. The terrain in the park is simply too steep to build such a structure and would be impassable to any vehicle. This naturally rugged terrain is a common feature along much of the Southwestern border and serves to deter any kind of vehicle access. Any attempt to fence off and wall these sections of the border would, ironically, end up creating roads and access routes through terrain that was previously impassable, as has been seen in other parts of the border where roads and fences have been built.
So far, more than 800 species have been identified as part of the Border BioBlitz, with more species IDs sure to come over the ensuing weeks. Not a bad count considering the timing of this survey: It’s essentially still winter in the area, so very few reptiles, amphibians and insects were present due to the cold weather, and Neotropical migrant birds from Mexico and Central America have yet to arrive in this part of the region.
As the day came to a close, and we re-entered internet space (there is little to no cell coverage in many parts of the Borderlands), there was great excitement to see the results of the Border BioBlitz streaming in by the minute from the Tijuana wetlands, Organ Pipe National Monument and Santa Ana NWR as we were uploading our photos and observations from the day.
At no point throughout the day did anybody ever feel like we were on a border. There was no sense of danger or lawlessness, as the national media and politicians would lead you to believe. It didn’t feel like we were on the edge of two countries. We were simply experiencing wild nature in a remarkable space. Earlier that week, Mikayla Mace, a reporter with the Arizona Daily Star in Tucson wrote, “The U.S.-Mexico border is not the outer limits of each country, but rather the heart of the region.” Coronado National Memorial embodies this like few other places, and that’s what we felt while were there: a lot of heart.