The clock was ticking, but Gary Hevel was off to a fast start. Only moments into the Rock Creek Park BioBlitz last spring, the Smithsonian scientist had already found two—no, make that three—insect species to count toward his 24-hour total—and that’s before he left the parking lot.

An entomologist at the Smithsonian’s National Museum of Natural History, Hevel was one of about 100 specialists from the Smithsonian and other science research centers, along with members of the public keen on natural history, enlisted to count animals and plants for a species census running from noon to noon May 18 to May 19 in Rock Creek Park, the 1,700-acre green heart of Washington, D.C. The goal: to create a snapshot of biological diversity in the nation’s oldest urban national park, Rock Creek Park, which was established by act of Congress in 1890, the same year as Yosemite National Park.
At present, the count is 665 species, among them 17 kinds of amphibians and reptiles, 29 birds, 20 fishes, 12 mammals, 52 fungi and 232 terrestrial plants. But those figures are growing as a few participating scientists are still at work carefully identifying and tallying their specimens.

Hevel’s personal contribution to the haul numbered 140 species of beetles, flies, ants, butterflies and other insects. A public information officer in the Entomology Department at the Natural History Museum, Hevel helped organize one of the first bioblitzes in the United States in 1996 at a park along Washington, D.C.’s Anacostia River. Since then, there have been bioblitzes at dozens of locations inside and outside the United States. The Rock Creek BioBlitz was the first of 10 such annual events planned by the National Geographic Society and the National Park Service at urban parks across the United States.

For managers of a park such as Rock Creek, the benefit of a bioblitz is obvious. You can only protect what you know you have, and setting loose a hundred biologists to search from the bottom of the park’s streams to the top of its trees is the quickest way to discover which species were calling the park home, or at least a nice place to visit, during 24 unseasonably cool hours in spring 2007.

For scientists taking part in the census, specimens from a bioblitz provide a record that can help in analyzing the distribution of species and changes in the environment. “Some of the specimens may show the presence of invasive alien species,” says Hevel, who at the Rock Creek event collected an Asian tiger mosquito, “a fierce biter and dangerous vector of diseases” that first entered the United States in the 1980s.

Minutes past noon on day one, Hevel had already bagged two species. Number two was a pale green luna moth (one of the largest American moths) that he held between his thumb and index finger. He’d plucked it from atop a tent set up at the bioblitz base camp. “Number one was a March fly I found in the restroom,” he said, pulling a glass bottle from his pocket to show the small black insect inside.

Next, his glance fell on the nests of some tent caterpillars—bioblitz find number three—in a tree at the edge of the parking lot. Pausing at the curb between pavement and forest, Hevel said he’d be sure to collect a few of the caterpillars before the event was over.

“Keep your eyes open, everybody—on the ground,” Hevel instructed as he set off into the woods trailed by three young boys, larval entomologists carrying their own collecting nets and brought to the bioblitz by their mothers.

One of the great things about many bioblitzes is that they offer children and adults the opportunity to join scientists in the field. Back at the parking lot, signs had been posted for different taxonomic groups—from soil invertebrates to fish and fungi—and at each sign, volunteer searchers stood in queues, awaiting their scientist guides.

“You like catching bugs?” asked one of the boys following Hevel. “Yeah,” the scientist confessed with a chuckle as he stripped bark off a dead log on the forest floor. Carpenter ants and wood roaches fled from the sudden sunlight.

While Hevel identified insects and demonstrated how to wield a net, other scientists were fanning out through the park. Smithsonian Entomologist Wayne Mathis netted shore flies—finding more than 40 species—while his museum colleague, Don Davis, hunted for the tiny micromoths that are his research specialty.

Periodically, the collecting forays were interrupted for identification sessions back at base camp. Sitting at tables under tents, scientists picked through specimens, consulted field guides and tapped at laptop computers. “We’re the mosses,” someone piped up helpfully from a table where several researchers sat surrounded by mounds of soft green vegetation.

Not far away, Hevel sat at his microscope wielding tweezers to sort through the insects gleaned from his first attack on the woods of Rock Creek: “Mostly flies. There are a few parasitic wasps and a couple of leafhoppers. There’s one little ant that could be very interesting.”

After dark, Hevel was drawn to the lights on the walls outside the park’s nature center, where he nabbed a moth fly and a micromoth from the oecophorid family. By the end of the bioblitz, Hevel and other entomologists had collected some 250 species of insects. With better weather—warmer and more humid—the figure would have been far higher. “C’est la vie,” sighed Davis, who has taken part in bioblitzes in the Great Smoky Mountains in which more than 500 species of moths were collected in 24 hours.

But biodiversity begins at home, and Gary Hevel can prove it. On tables near his microscope, he had arranged 18 glass-topped drawers borrowed from the museum’s insect collection. They contained mounted specimens representing just half of the 4,000 insect species Hevel collected in his Maryland backyard between 2000 and 2004.

To identify such a broad array of different insect species, Hevel relies on his own knowledge, the expertise of staff entomologists at the Natural History Museum and the museum’s reference collection of some 30 million insect specimens. Scientists use the collection on a daily basis to help identify and turn back potential insect pests at U.S. borders that are hitch-hiking on shipments of fruit, vegetables, flowers and other imported products.

In addition to its collections, Hevel says, the Entomology Department also keeps a wealth of manuals, guides and background information on each species that has been amassed over time—such as what plant it was feeding on when it was collected, the general time of year the insect emerges, variation within species, as well as between species, and the different patterns within a species.

Hevel’s extended personal bioblitz at home may have set a world record for the number of species collected by one person in one location. His backyard project also makes a strong case for the idea that you don’t have to visit the rain forest to find remarkable creatures.

Keep your eyes open and on the ground, and you may even help save the game of baseball. Among Hevel’s backyard finds was a small wasp that at the time had been collected only once before in the United States. The wasp was an immigrant from Asia, and so is a beetle that it parasitizes—the emerald ash borer. Discovered in this country in 2002, emerald ash borers are considered a grave threat to America’s ash forests, the very forests that have long provided the wood of choice for making professional baseball bats.

Several of Hevel’s backyard wasps were rushed off to scientists in Michigan who are trying to identify insect allies that might help in battling ash borers. “It’s a big world, isn’t it,” remarks the entomologist before turning back to his microscope and the tiny world on its stage.