PROVINCETOWN — The coordinates came with a warning: “The information I just shared … is protected and confidential.” The sender, Alexander Richards, a Ph.D. student at UMass Boston, had gotten approval from at least two other scientists to show a reporter and photographer the location, but he didn’t want it leaked.
When we arrived, Richards was there and, first thing, sprayed our boots down with a disinfectant to prevent us from contaminating the environment. As we walked, Richards pointed out details about the habitat, then asked us to strike those from the record to prevent the information leading someone to this spot.
The reason for all the secrecy that late September night was that we were on the trail of the eastern spadefoot toad, a once-widespread species that is now rare and listed as threatened under the Mass. Endangered Species Act. Richards and other spadefoot biologists have heard stories of other reptile and amphibian biologists who’ve had their study species poached. The rarer an animal is, the more collectors want to find it, he said.
Spadefoots were once widespread across eastern Massachusetts, Richards said, but pesticides and development destroyed many of the vernal pools where they lay their eggs, leaving their populations fragmented. And the populations that remain now face a threat from another source: chytrid fungus.
The fungus burrows into the skin of amphibians, which prevents them from breathing through their skin, causing them to suffocate, Richards said. A 2019 review in the journal Science found that the disease was involved in the extinctions of 90 amphibians and caused declines in over 500 other species; the journal called it the cause of “the greatest loss of biodiversity attributable to a pathogen.”
Spadefoots are definitely vulnerable to the fungus; about a fifth of the toads that get infected with it die within three weeks. In some Massachusetts spadefoot populations, such as those in Rehoboth and Plum Island, up to 50 percent of sampled toads appear to be infected.
But in Provincetown, which Richards said holds the largest population of spadefoots in the state, only 8 percent of the toads show the presence of the fungus. More remarkable still, Richards found that not a single Provincetown toad had the hallmarks of severe infection. It seems the spadefoots are getting infected less frequently here and appear to be fighting the infection better than toads on the mainland.
Richards is out to figure out why. He hopes his research will reveal a new aspect of spadefoot biology and help scientists protect other spadefoot populations. “I think the populations that are healthy can have a lot of hints,” he said.
Wearing high-powered headlamps, Richards walked into the dunes, hoping to catch the toads’ eyeshine. After a few minutes of walking, Richards spotted a toad sitting under a bush. It’s a sandy-colored, smooth-skinned animal. “Such cute little eyes,” Richards said, as he and the toad looked at each other.
Richards put on medical gloves, which he always wears when handling toads to avoid contaminating their sensitive skin, and picked it up. He measured it — Provincetown spadefoots are notably large, he said, likely due to the abundance of insects for them to eat here — and weighed it in a plastic bag. Then he added a mixture of water and salts that he called “artificial pond water” to the bag and closed it. He tucked the bagged toad in the bushes, and the search continued.
Thirty minutes and a few more bagged toads later, we returned to begin the next step in Richards’s data collection work. He removed the toad from the bag, then poured the water from it into a vial. The water, he said, had by then stimulated any chytrid fungus present to release its spores, so testing this “frog juice,” as he called it, would reveal whether the toad was infected.
The water also contains bits of the toad’s DNA. Richards wants to sequence it and compare it to the DNA of other toad populations. It might be he’ll find some important difference in this population’s genetics.
But Richards’s main theory doesn’t have to do with the toads themselves. Instead, he hypothesizes that our local spadefoots’ resistance to the fungus may be thanks to microbes living on their skin. To test this, he takes a swab and rubs it on the underside of each toad he bags, being careful to get each of its digits and foot pads. Back at his lab in Boston, he will compare the microbes on the Outer Cape samples to those from other populations.
Richards is also testing other theories, including whether the salinity or pH of the soil here might have some effect on the toads’ fungus resistance.
In only a couple of hours Richards found eight spadefoot toads not far from one another. Since these toads are social burrowers, they sometimes burrow right next to each other. And often, they’ll burrow right next to a road, he pointed out.
The Outer Cape’s spadefoots may be faring better than other populations, but they aren’t invincible. Richards said that cars pose the biggest threat to their survival. Indeed, he said, one of the reasons people first knew there was a large population of spadefoots in Provincetown was because a large number were found crushed by cars during the toads’ spring migration to their breeding sites.
The Cape Cod National Seashore for a time closed the roads in the Province Lands for the first few rainy nights of spring when spadefoots and Fowler’s toads were migrating. The days were chosen based on when rain was forecast and whether water levels in the area’s nearby wetlands were optimal for spadefoot breeding, according to Susan Reece, chief of interpretation, education, and cultural resources for the Seashore.
That program was discontinued in 2016, not because it wasn’t effective but because of a lack of resources, said Reece.
Richards said he is hoping to establish a road closure program run by volunteers next spring to protect his beloved spadefoots. “They would only have to close it two or three times per spring,” he said, adding that he has spoken to a few National Seashore scientists about the idea but has not officially pitched it yet.
This reporter and photographer Emily Schiffer went home from our toad assignment at about 11 p.m. But Richards said he stayed out looking until 2 or 3 in the morning. With every toad he samples, the chances are better that he’ll find a way to protect one of the state’s rarest amphibians.
