Opinion

Croaking: Science's New Normal?

Merging ecological emergencies and funding cuts made for one gloomy 'world summit' of herpetologists this year.

By Leslie Anthony 17 Nov 2012 | TheTyee.ca

Leslie Anthony holds a PhD in zoology from the University of Toronto and is the author of Snakebit: Confessions of a Herpetologist, published by Greystone Books in 2008.

First there was the doom: a raft of presentations documenting the impacts of clear-cutting, invasive species, toxic chemicals, parasites, disease and the time bomb of climate change. Then the gloom: a collective realization among 1,700 scientists from 48 countries that these forces, acting in concert, had produced an apocalyptic symphony, and their decades-long mission to document, understand and preserve biodiversity among the world's 14,000-ish species of amphibian and reptile had probably come to this: an act of global triage.

Such was the mood blackening the hallways at the University of British Columbia this past August during the Seventh World Congress of Herpetology (herpetology being the study of amphibians and reptiles). Having attended the first World Congress in Canterbury, U.K. in 1988 as a wide-eyed doctoral student, and similar gatherings over subsequent decades as a researcher and journalist, the week-long Vancouver affair was indeed remarkable for its melancholy -- contra the typical joie de vivre of the scientific community's oddball fraternity. Missing was the puffing, posturing camaraderie that stems from studying -- sometimes surviving -- animals that are the stuff of other people's nightmares.

As a driving force behind the molecular methodologies of modern taxonomy and population analyses, herpetologists have long claimed the forefront of conservation genetics and ecology. It's an unfortunate irony, given the theme that dominated this summer's World Congress: collectively, their study organism are now the most endangered vertebrates on earth.

Decades of cutting-edge research demonstrating how important reptiles and amphibians are in global ecosystems have done little to stanch their demise. Both play key ecological roles in energy transfer between water and land, a trait that confers vulnerability to degradation of either environment. Confined primarily to moist environments by the permeability of their skins, many amphibians also have biphasic lifestyles in which aquatic larvae become terrestrial adults. Adult amphibians voraciously consume water-bred (often disease-carrying) insects; in turn a host of snake and lizard and bird species consume both larval and adult frogs, toads and salamanders. Mammals, birds and snakes rely on lizards for food, most lizards rely on insects, and turtles are top carnivores and main scavengers in many aquatic ecosystems. The group isn't simply part of the general food-web house of cards, but a trophic Jenga of its own.

Long the villains of many a folk tale, being overlooked is nothing new for reptiles and amphibians. But historical prejudices swept aside, it's clear that an overwhelming conservation focus on charismatic megafauna (lions and tigers and panda bears, oh my!), combined with an evolving societal view of science as nothing more than a lapdog of industry, are contributing to a current crisis in herpetology. And perhaps it's not alone.

Herptiles under siege

The gloomy tone of the World Congress was set by Dr. Tyrone Hayes of the University of California at Berkeley in his opening address on the effects and impact of the herbicide atrazine -- 80 million tons of which is dumped on U.S. cornfields and golf courses each year. Dogged and revealing research on the chemical widely present in both rain and tap water has made Hayes both an enemy of industry and a genuine celebrity, with a day named in his honour in Minneapolis and a film collaboration with Erin Brockovich.

Atrazine has been shown to demasculinize, sterilize and even feminize males across all vertebrates, including compromised reproductive health in humans. Like many toxins, atrazine also hurts immune function, increasing susceptibility to disease. Hayes' thesis was that "a" cause of amphibian declines did not exist; rather, the main culprit was chemical contaminants like atrazine interacting with other factors.

"It's not like we've done just one thing here, but far too many -- and now interactions are the problem," Hayes offered the audience. "Pathogens, parasites, habitat modification and climate change all serve to increase the effects of pesticide exposure."

Ecotoxicology, a difficult field requiring foundations in ecology, physiology and chemistry, has recently been made more difficult.

"There are serious declines in support and interest," noted Dr. Donald Sparling of Southern Illinois University in his own talk on the global impacts of contaminants, "and less money means less research."

Translation: when it comes to attracting monies, feminized frogs aren't as sexy as dead ones.

Funding cuts and an anti-environment political climate -- particularly in the host country -- loomed large, but there was more. Symposia comprising over 1,000 studies were dominated not by the usual ecological and evolutionary topics, but by battles with invasive species, conservation skirmishes involving hundreds of threatened species, and all-out war on disease. This litany added up to the scary phrase "New Normal" bandied at every coffee break: in other words, that these were no longer ephemeral or stand-alone issues, but a merger of ongoing problems accelerating rapidly to an unknowable end game. Herpetologists had ceased believing they could safeguard biodiversity and were instead merely coping with the disaster upon them, hoping to learn enough to deal with an imminent ecological meltdown.

Not all of this was new. Invasive species fires had long smouldered at meetings, like the many incursions of the Cane Toad (islands, particularly Australia) and bullfrog (including British Columbia) that decimated native amphibians and altered local food chains. At the World Congress, however, these had fanned into full-blown conflagrations. Ditto the swarm of alien Burmese pythons in South Florida; more novelty than threat a decade ago, they were now some 150,000 strong, responsible for the virtual disappearance of small mammals from the Everglades and a proven predator of critically endangered birds and mammals. Other talks focused on how introduced organisms as diverse as fire ants, crayfish, fish, rats, tree frogs and lizards were spreading disease and radically changing ecologies everywhere.

On the disease ledger, Batrachochytrium dendrobatidis, or "chytrid," the microscopic fungus plowing through the world's amphibians -- primarily in remote and pristine areas -- had been a fixture of meetings since its identification in 1998. This plague has been seen as the main culprit in the disappearance or endangerment of 36 per cent of the planet's 6,000-plus amphibian species, but the New Normal turns the received view on its head. As Sparling demonstrated with analysis of studies like those of Hayes, pesticides like atrazine applied in lowlands like California's Central Valley -- which grows 50 per cent of America's food -- are aerosolized on the wind and carried aloft to be deposited into otherwise pristine mountain ponds. Such high-altitude areas in the Sierras have indeed experienced massive frog die-offs, and this "montane paradigm" also pertains to Central America, the Andes, and possibly the east coast of Australia, areas of the worst chytrid disasters. "Most amphibians currently in trouble live in an area that fits a model of oceanic effects from lowland agriculture meeting a mountainous region," Sparling concluded.

Furthermore, forensic DNA studies revealed new strains of the fungus have emerged and/or been moved around by invasive species to increase susceptibility to already immune-compromised and chemically stressed frogs. As Hayes had suggested, the unstoppable chytrid epidemic likely doesn't have a single cause -- nor so infectious diseases posing new significant threats: ranavirus outbreaks in amphibians, reptiles and fishes in the Americas, Europe, and Asia have featured death rates exceeding 90 per cent, while the once-rare "chelonian herpesvirus" is increasingly behind mass turtle die-offs globally.

Climate: off the scales

None of this should be surprising. Studies have made clear how the cavalier practices of big agriculture in general, and those around GMO crops in particular, have contributed to Colony Collapse Disorder in honeybees and declines in butterflies. The documented effects of agrichemicals on human health range from dozens of cancers, through increasing prevalence of Parkinson's Disease, infertility, miscarriage, birth defects, autism, and even obesity and diabetes. Imagining the toll on animals that bathe daily in the toxic soup of human progress isn't much of a leap (pun intended), and if there was anything truly new here it was the accelerant being poured on these fires by climate change.

In Vancouver, Dr. Barry Sinervo, evolutionary biologist at the University of California, Santa Cruz, updated his landmark 2010 study, which demonstrated that even under the most optimistic scenarios for curbing CO2 emissions, one-fifth of the globe's lizard populations -- corresponding to six per cent of all species -- will be extinct by 2050.

"We have committed ourselves to this [much loss]," he lamented. "This is the baseline."

Climate change, he added, had driven 12 per cent of Mexico's colourful Sceloporus lizards extinct since 1975, and because warming triggers tree death and vegetative die-back, such ecosystem-level changes will exacerbate the heat and water stress on lizards, particularly those dependent on vegetation. Springtime temperatures are now so high in California that lizards hide in shade when they would normally be feeding and mating. If carbon emissions continue at current levels, by 2080 39 per cent of the world's lizard populations will vanish. While the ecological implications of this can't be known, it's worth noting that lizards are primarily insect eaters; when a population goes extinct, insect populations explode.

"The New Normal is already off the scale in the tropics," warned Sinervo. "And the average summer temperature at the end of the century will be higher than the highest temps ever recorded at most tropical sites."

If Sinervo is even close to right about the added stress of a warming climate, the world will soon be a very different place. Was there a take-home?

"It is clearly the interaction of multiple threats," allows Purnima Govindarajulu, a herpetologist at the B.C. Ministry of the Environment who has worked on invasive bullfrogs on Vancouver Island (they're expanding), province-wide surveys for chytrid (it's everywhere), and a range of species recovery projects (now threatened by federal softening of the Species at Risk, Environmental Review and Navigable Waterways Acts). "That the total impact is often greater than a simple sum of parts -- and far more worrisome -- speaks to how our current techniques are pretty poor at predicting or even tracking interactions."

Part of the problem is that science funding models favour reductionist research -- where complex issues are broken into their simplest components for study. So although much might be learned about a cause of decline in a species -- such as a disease or parasite epidemic -- little is known of the conditions that led to it. Though useful, such studies are proving to be dust in the wind of a much bigger picture.

Would you live here?

For many attendees of the summit, "habitat" was the elephant in the room, the thing that no one -- and few funding bodies, tied as they are to governments -- wants to acknowledge. And yet every study of declines ultimately points back to loss and degradation of habitat. It's a simple equation: animals dwelling in non-optimal conditions are ecologically and genetically stressed; add a litany of toxic chemicals, a rapidly changing climate, and a host of competing invasive species and you have a formula for emerging diseases, collapsing food webs, population crashes, and widespread extinctions. It's Silent Spring on steroids in a figurative sense, and, given the now widespread environmental presence of such molecules, literally as well.

Such knowledge is no help without political will and regulation -- particularly with the voracious land-gobbling of Big Agriculture. The rare desert ecozone of B.C.'s south Okanagan Valley shares the highest number of species at risk (more than 60) in Canada with one of the country's fastest-developing communities. Severe pollution, invasive species, and loss of 84 per cent of wetlands bode poorly for its 15 species of amphibians and reptiles, with two already extirpated and the remainder endangered, threatened or of special concern.

University of Waterloo researcher Sara Ashpole has worked on wetland rehabilitation in the beleaguered Okanagan for a decade.

"The conclusion I came away [from the Congress] with was that we are now accepting marginal habitats when we shouldn't. Say you're studying 'occupancy' of frogs in agricultural areas. Well, we know they can exist, but if your study is only a snapshot of one or two years -- because of funding -- how do you measure population dynamics or success?"

Meaning, you don't. In spring, ditches and ponds in agricultural landscapes may contain enough water for frogs to reproduce, but are marginal in that they also contain loads of chemicals and feature high temperatures and unhealthy numbers of pathogens and parasites that lead to low hatching rates, poor survival to metamorphosis, and illness in adults. The study will conclude the animals are present -- be they diseased, dying or disappearing -- and government, agriculture and property owners will smile and say "See? It's OK. We have frogs!"

"These types of studies give permission for accepting marginal habitats, sending the message that these can replace natural habitats," says Ashpole. "That shouldn't be part of the New Normal."  [Tyee]

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