Amphibians today are experiencing a population crisis of unprecedented scale. Frogs are going extinct, according to the most conservative estimates, at two hundred and eleven times the background extinction rate, and in the past three decades many dozens of species have simply disappeared, wiped wholesale from existence by a complicated net of global factors. A clear threat to the biodiversity that lays at the base of ecological stability, the die-off of the amphibians also represents a potential elimination of a key link in the chain of global biomass distribution. Amphibians eat insects, and are in their turn eaten by a number of species. Remove the amphibians, and you significantly affect access to all that baseline insect protein which ecosystems depend upon.
The question of why the amphibians are disappearing is a thorny one, involving analysis of multiple overlapping factors, but sifting through them has been made easier thanks to the work of a prescient scientist who saw the coming threat two decades before researchers began seriously documenting it and resolved to carry out experiments to determine how amphibians react to ecological change. She was Margaret Stewart (1927-2006), the author of the first guide to the amphibians of Africa in 1967, and a scientist who established the impact of heat, territory, sound, and water changes on native and invasive amphibian populations throughout the 1970s and 1980s.
Born on a hundred acre farm in North Carolina, Stewart had the benefit of immediate access to nature, and parents who were eager to explain its mysteries to her. In between the necessary chores of farm life, her mother and siblings regularly took to the surrounding forests and streams. Her mother, Mary Ellen Stewart, shared the names of the animals and plants around them, while her sister passed on her enthusiasm for learning bird songs and identifying nests and butterflies. When not tromping in nature, Margaret devoured the pages of National Geographic and reveled in the photo essays of distant places and cultures, resolving to herself that she would never settle for a hum-drum existence, that her life would be full of sights yet unseen in lands unknown.
Arriving at the University of North Carolina's Woman's College, it was more or less a given that Stewart would make biology and in particular ecology her field of choice, but the question of which species she would specialize in required some deep thought. Birds and the creatures of the sea both held intense interest for her, but ultimately she settled on amphibians as a class vastly understudied and poorly understood from an ecological perspective. Her master's and doctoral work focused on salamanders, a logical enough choice given that western North Carolina's Highland Biological Station was at the time the world's premier location for the study of salamander populations. She received her Master's from the University of North Carolina at Chapel Hill, and received her PhD from Cornell University in 1956, whereupon she joined the faculty at what is now the University of Albany.
By any outside standards, her career so far was an unqualified success. She had obtained a doctorate and a steady teaching position before her thirtieth birthday while having amassed a solid base of research at a world-renowned center in a field she loved. Impressive, but the voice of Young Meg still rang in the back of her head - what happened to exploring the world? What happened to new lands and sights unseen?
Those, it turned out, would have to wait for 1963, when she and her first husband set out for Nyasaland (now Malawi), he to make recommendations for the establishment of the country's first national park, and she to study the frogs, lizards, and snakes of the Nyika Plateau. For one remarkable year, she would scour lion-populated regions for frogs of dazzling colors, and come regularly into contact with some of the world's most dangerous snakes while amassing the field notes which remain important to any herpetologist setting out for the African continent. She enlisted the help of local populations to bring her new specimens and basked in the freedom of being truly by herself in a strange natural setting, free to set her collection schedule entirely as she saw fit, returning to civilization from time to time to cross-reference her finds with those of nearby museums and libraries.
It was a charmed existence, and she was instantly ready to return for a longer, five year, stay, when growing personal problems with her husband culminated in a divorce that scotched any plans for a return trip. Stewart combined her notes with eighty drawings and photographs she had personally drawn and taken to produce in 1967 Amphibians of Malawi, which includes her descriptions not only of the species she had collected for the first time, but an incredibly helpful guide to herpetological collecting in a foreign country which remains a useful source for the fresh field researcher. One of the species she documented, Phrynobatrachus stewartae, bears her name and is commonly known as Stewart's puddle frog.
She had produced a landmark text documenting the reptiles and amphibians of Africa, but would never herself return. She devoted herself to teaching, throwing herself into the task of introducing primarily urban students to the delights of field studies, bringing many of them out into the wilderness for the first time, showing them the interconnectedness of the landscape and living creatures first hand, and changing not a few lives in the process.
But the itch to do research beyond the Adirondacks remained, and in 1966 she took her first trip to the Caribbean to study frogs in Jamaica. Two native species of frog there were facing stiff competition from two invasive species and Stewart wanted to know how it was that newly arrived frogs could out-compete frogs that had theoretically adapted specifically to their environment over the course of millennia. Her second husband, mathematician George E. Martin, while having no desire to go to Africa, was quite amenable to regular return visits to Jamaica for research, and so Stewart began her studies in drought and heat resistance in frog populations that explained not only the dominance of the invasive frog species, but pointed to the fragility of amphibians' grasp upon their spot in nature.
In the following years, Stewart rolled out numerous studies, from her research in Jamaica, Puerto Rico, and throughout the United States, pointing to the effects of sound, access to water, slight variations in heat, and crowding on the life cycle and ultimate fate of different frog populations, all of which pointed to one overriding conclusion - the disappearance of habitat, if kept at its current pace, has the potential to hit these species hard, and consequently to disorder the vast webs of interdependence that rely upon their role as insect consumers.
Conservation was Stewart's watchword as her research uncovered more of the fragility of native species in the face of radical change. She devoted herself to the attempt to save the Pine Bush, a region of rare species tucked between Albany and Schenectady which had by her time already suffered the loss of eighty percent of its habitable land to urban sprawl. What was once twenty-five thousand acres chock full of protected species had been winnowed down to a mere four thousand, and Stewart wanted to ensure that those slim acres survived not only for their own sake, but to teach future generations important ecological lessons. For twelve years she served on the Albany Pine Bush Preserve Commission, a stretch of service for which she was recognized in 2004.
Retiring in 1997 from official teaching duties, Stewart immediately undertook the task of becoming a founding director of the University of Albany's groundbreaking Graduate Program in Biodiversity, Conservation, and Policy, providing programs that would train future generations to recognize, categorize, and act against threats to the environment that earlier generations could only grimly record while all around them nature burned. The establishing of that program set the cap on a career that had included the publishing of a landmark text, the first woman presidency of the American Society of Ichthyologists and Herpetologists (in 1979), four decades of inspiration as a teacher, and the production of a wealth of data concerning the interaction between amphibians and environment. Honored by multiple awards and professional memberships throughout her life, she died in 2006 having seen farther than most, and prepared the tools that would be picked up thankfully by those to follow, whensoever they might catch up.
FURTHER READING:
Margaret Stewart, once an important voice in conservancy and ecology, is something of a shadow now, a mere eighteen years after her death. ResearchGate has links to some of her papers from the late 70s through early nineties here. Otherwise, besides a few brief obituaries here and there, your best place to find out about her is either through obtaining a copy of her 1967 book on amphibians or flag down a copy of the book where I first came across her, Anne LaBastille's highly interesting Women and Wilderness (1980), a collection of profiles of women either researching or engaging with nature that benefits from actually having interviewed Stewart.
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