MEDFORD — Bryan Hamlin did not expect to find much of interest when he and his wife, Anne, embarked one Sunday in April 2003 on a walk through the Middlesex Fells Reservation, the large nature preserve near their new house.
Hamlin — a plant lover who had “botanized’’ in far more glamorous landscapes — entered the Fells with modest expectations. But as they hiked deeper in, he was impressed by the richness of the flora, and started noting what he saw.
“This place isn’t so bad,’’ he recalls thinking.
So when he came across a Boston University study reporting 155 plant species had disappeared from a section of the Fells over the last century, he vowed to give the matter a second look, a “proper follow-up.’’
Now, after a nine-year quest, Hamlin and collaborators have documented finding 105 of the purportedly lost species. And he says he’s learned that citizen scientists can make important contributions to science, though he fears they’re often not heard.
The authors of the original 1996 paper, Richard Primack of Boston University and his graduate student at the time, Brian Drayton, say Hamlin’s work doesn’t undermine their basic conclusion — that the number of native species is declining as nonnative plants increase — but credit the citizen-organized effort with providing a more complete data set.
Hamlin’s team surveyed the entire reservation and spent far longer looking — 2,000 hours, versus less than 400 by the BU team — which accounts for part of the difference in their findings.
Hamlin, 72, a skilled amateur botanist who did his first plant survey as a boarding school student in England, typically dons a fisherman’s vest when he goes out into the field. He fills the pockets with a magnifying lens, a notebook, and two pens — in case one fails — and an old knife that his wife won’t miss to take samples.
Even in winter, he will halt over a pile of dried leaves, his blue eyes widening behind round wire-rimmed glasses, as he recalls the drama of spotting something quite wonderful there in another season: a very rare buttercup.
Back when he began his study of the Fells, Hamlin was winding down his peace work for a non-governmental organization, which involved traveling to conflict-prone areas of the world to help facilitate dialogue between opposing groups. Even during those trips, greenery was never far out of Hamlin’s mind. In Israel, he once pulled over to jump a fence and take a photo of a giant hollyhock while his traveling companion, an imam, looked on in confusion.
A microbiologist by training, Hamlin kept a spreadsheet and recorded where he found plants in the Fells and whether they were blooming. He brought his tripod and camera into the woods at times and used the cluttered solarium of his Medford house to do plant pressings, stacking encyclopedias atop samples to dry them out.
Amassing the list became like a personal challenge and the botany of the Fells his avocation — one that would outlast two other stints, first selling insurance door-to-door, and then substitute teaching.
Early on, at the urging of Betty Wright, one of his collaborators, he approached Primack at a meeting of the New England Botanical Club to present a list of the team’s initial discoveries. Primack, he recalled, was not dismissive but said he was then focused on conducting a far more detailed survey of the flora of Concord.
Hamlin recruited other team members, to make up for his own shortcomings. Walter Kittredge, a skilled botanist who works at the Harvard University Herbaria, joined the effort. So did Donald Lubin, knowledgeable about ferns.
The team ultimately prepared a painstakingly-researched, 79-page scientific paper that was published last year in the journal Rhodora. Parts of it agreed with the general findings of the BU report — for example, the number of nonnative species had tripled in the Fells, and the majority of native plants that were rare in 1895 were either not found or stayed rare.
But there was one major difference: Hamlin and his researchers rediscovered two-thirds of the “lost’’ species.
“We’ve always been quite cordial about this, because that’s the way science happens,’’ said Drayton, who now works at TERC, a Cambridge nonprofit organization involved in science education. “Our conclusion that there was substantial species loss, though not as substantial as I thought. . . I think that stands.’’
Science is a conversation, with competing results building off one another, and Primack said he and Drayton plan to write a letter to Rhodora presenting their response. But Hamlin has become philosophical about the relationship between amateur and professional scientists. He learned of a separate community of naturalists in Concord who, despite also having respect for Primack’s work and his conclusions, raised similar concerns about the completeness of his plant inventories.
“We and others believe, for example, that a list of ‘lost’ or ‘extinct’ species compiled by Dr. Primack and his co-workers represents more a list of what they happened not to be able to find rather than a list of what is truly gone,’’ Ray Angelo, a skilled amateur botanist and close observer of Concord’s flora, wrote in an e-mail. “This is not to say there has not been change in Concord’s flora for a variety of reasons.’’
In a way, the debate over whether a particular species still grows shines a light on how science works. Primack recognizes the importance amateurs have played in his own work, helping guide him to the right spots and productively critiquing his observations with their local knowledge. But he added that professional scientists, looking for the effects of long-term changes, sometimes have different goals than amateurs.
Primack said he and his colleagues have waded waist-deep into numerous bogs in Concord, searching for the once-abundant pitcher plant. A naturalist and longtime resident, Cherrie Corey, informed him the plant was still in Concord, in a bog called Gowing’s Swamp.
Primack said she’s probably right. But he added that the large swamp has an unstable surface, making it difficult to access.
“She will say I’m wrong because there are pitcher plants in Concord, but a species which used to be extremely common is now extremely rare,’’ Primack said. “It’s a difference in perspective.’’
Hamlin notes that even single, rare stands of plants can be ecologically meaningful: a lone rare plant could mean the plant is vulnerable and on its way out. But a rare plant could be gaining a foothold — which could also be an indicator of environmental changes. Hamlin has seen both in his data.