Sue Muller carefully scraped the dry dirt from a spot along Columbia’s Lake Elkhorn walking path, using a small garden trowel and a water-filled spray bottle to soften the earth until she saw the white of turtle eggs peeking through.

The Howard County naturalist kept at it, slowly carving out the rectangular hole painstakingly dug two weeks before by a ridge-backed turtle of a species normally found along the Mississippi River. Muller stopped for a time to invite passers-by Lucas Julian, 6, and his mother, Irene, of Clary’s Forest to watch and learn, but then returned to her main task.

“It’s the first non-native species at Lake Elkhorn,” said Muller, who works for the Department of Recreation and Parks and is the county’s coordinator for a five-year statewide study of reptiles and amphibians. The false map turtle found June 17 might not seem like a threat, but “it’s out of its ecosystem,” Muller said. It could change the Maryland landscape in unintended ways if allowed to breed.

The discovery at Lake Elkhorn is timely in light of the state study, according to state and county officials, because it highlights the need to keep track of the animals living in Maryland.

For Muller, the episode reinforced two important themes — encouraging people to step up and be volunteers in monitoring the natural world, and keeping careless acts from permanently altering that environment.

“It’s a great lesson for people to know about not dumping your pets,” Muller said.

She’s assuming that’s how the false map turtle got into the Columbia lake. The turtle is distinguished by its unusual pointed shell, which is adorned with the patterns that inspired its name. The species also has yellow zigzag marks along each side of its head. Turtles can live for 60 years or more, and some who buy one for a pet tire of it or see it grow bigger than they are comfortable with and release it into the wild, Muller said.

Kathy Colston, a Columbia resident who became acquainted with Muller after volunteering for earlier bird surveys, accidentally discovered the unusual-looking turtle during a walk along the lake’s southern shore. She quickly reported it to Muller.

After digging up the eggs, Muller took them immediately to the Clarksville farm of Ray Bosmans, president of the Mid-Atlantic Turtle and Tortoise Society, who promptly put them in a homemade incubator.

Bosmans and Muller must now wait two to three months to see if the eggs were fertilized, and if so, what emerges when they hatch. Turtles don’t return to the eggs they lay, so the mother will never miss them. The big question is whether she bred with another false map turtle, with some other, native turtle species, or just laid unfertilized eggs, Muller said

Scott A. Smith, an Eastern Shore-based state ecologist, said Maryland’s reptiles and amphibians haven’t been catalogued and mapped since 1975, when 97 species of creeping, crawling critters were identified. The current study will create a new list and an atlas showing where each of the current species is found.

“We’re basically trying to take a snapshot in time of what we have in reptiles and amphibians,” he said.

“Anything invasive can potentially disrupt the ecology of some of our native turtles or introduce disease,” he said. Volunteers play a vital role in finding all the species, especially since reptiles and amphibians are much harder to spot than birds, so officials are eager to enroll as many helpers as possible.

In Howard County, Muller said, she certainly can’t do the survey all by herself.

“I have an entire county to cover with at least 50 species to look for,” Muller said about the state study. Salamanders and snakes aren’t easy to see because they are naturally reclusive. “They’re hard to find — you’ve got to roll logs over.” People can also help by submitting audio recordings of frogs and toads calling mates.

While some people find snakes, frogs and turtles repulsive, they are “often the first experience children have” with animals, Smith said.

Bosmans, a retired horticulturalist, provides temporary homes for abandoned turtles found by society members or volunteers on the private parcel of land where he lives in Clarksville. He welcomes anyone who would like to adopt one, he said.

He’s carefully keeping the eggs Muller found in a moistened, 80-degree incubator, which is actually a 10-gallon fish tank, to see if they hatch, he said. His organization, which is devoted to promoting good treatment of turtles and preservation of their habitat, can be found at http://www.matts-turtles.org. The roughly 150 members meet three times a year, he said.