Tree frog, Calgary Zoo
The term “endangered wildlife” conjures images of grizzly bears, swift foxes and even the Alberta Liberal Party. Amphibians, being somewhat less glamorous creatures, don’t immediately jump to mind.
Habitat loss, pollution, climate change and a deadly fungus are all contributing factors in the rapid decline of the world’s amphibian population, which some conservation groups have likened to the disappearance of the dinosaurs.
While other animals facing extinction — often fuzzier and more photogenic — tend to grab the spotlight, the plight of amphibians should be sounding alarm bells, says Calgary Zoo conservation researcher Anna Hargreaves. “It’s naive to think that it’s just amphibians that are threatened,” says Hargreaves. “Amphibians are affected by a lot of things that affect other wildlife and will eventually affect humans.”
The Global Amphibian Assessment, a study conducted by the International Union for Conservation of Nature (IUCN), found that up to one-half of the world’s 6,000 known amphibian species are facing extinction within our lifetime. In order to mitigate the situation, the IUCN and the World Association of Zoos and Aquariums (WAZA), have named 2008 the Year of the Frog in order to raise public awareness and funds to address the issue.
In 2006, the IUCN, WAZA and the Conservation Breeding Specialist Group initiated a program called the Amphibian Ark with a mandate to develop rapid rescue and captivity programs at zoos, aquariums and botanical gardens around the world for amphibians threatened with extinction.
“There’s literally hundreds of zoos and aquariums around the world that are participating in this initiative to help do what we can to save these little guys from going extinct,” said Laurie Herron, communications manager for the Calgary Zoo. “Although this is the Year of the Frog, the efforts to save these frogs don’t end in December.”
According to Herron, captivity and breeding programs tend to be limited because of the relatively small amphibian population in northern climates. For its part, the Calgary Zoo will be hosting an amphibian husbandry course in late May for other zoos and aquariums to increase their knowledge of how to care for and breed endangered species in order to help them recover. “To improve our ability to respond and rescue specific species and breed them in captivity as an insurance population, you have to have the husbandry skills to do that,” says Herron.
Amphibians not only play a vital role in an ecosystem as both predator and prey, many have antimicrobial peptides in their skin to fight off invading bacteria, fungi and viruses, says Hargreaves. These peptides are now being studied for possible cures for a variety of human diseases. In 2005, researchers at the Vanderbilt University Medical Center in Nashville, Tennessee reported that compounds found in the secretions of the Australian red-eyed tree frog are potent blockers of HIV and may lead to a topical treatment to prevent the spread of the disease.
Despite the defensive mechanisms nature has bestowed on amphibians, the additional stresses of habitat loss, pollutants and climate change may be making amphibians vulnerable to a fungus that is laying waste to many populations around the world.
Chytrid is believed to have originated with the African clawed frog, which for years was used around the world in lab studies and human pregnancy tests. For decades, pregnancy tests were conducted by injecting a urine sample into a female frog, and if positive, would trigger the frog to lay eggs within eight to 12 hours. When more effective tests were developed in the early 1960s, the frogs were released into the wild, which may have led to the spread of the fungus. Untreatable in the wild, chytrid kills up to 80 per cent of amphibians it infects within months.
“A huge percentage of the leopard frog decline (in B.C.) has been attributed to the chytrid fungus and competition with [non-native] bullfrogs,” says Calgary Zoo veterinarian Dr. Doug Whiteside. In 2007, the Alberta Northern Leopard Frog Recovery Team tested 38 sites in areas mostly south of Edmonton and found chytrid present in six of the sites. “Based on the preliminary results, we’re hoping it’s not as prevalent as we’d initially thought it would be,” says Whiteside. According to Whiteside, chytrid requires water temperatures in the low 20s in order to survive and flourish. “With B.C. having a warmer climate than Alberta has, it’s definitely more amenable to chytrid growth in the summertime.”
A TOUGH TOWN FOR FROGS
One the most widespread frog species in North America, the northern leopard frog experienced a dramatic die-off in the late 1970s in Alberta. While some researchers believe the suddenness and magnitude of the decline indicates the presence of a disease, the exact cause remains unknown. In 1999, the Alberta Conservation Association and Alberta Fish and Wildlife initiated a reintroduction program, which saw over 13,000 juvenile leopard frogs released in the province, but ultimately failed to re-establish the leopard frog population.
Currently, the Alberta Northern Leopard Frog Recovery Team is looking at the translocation of egg masses to repopulate areas of Alberta. “The reason egg mass are chosen as opposed to tadpoles or little froglets is because the egg masses have the lowest chance of disease transmission between ponds,” says Whiteside. “We’re not looking at using captive breeding and release programs yet, but that may be something in the future.”
“While we see disease as the main thing that’s wiping them out, in most cases, frogs have lived with these pathogens for a long time, but they’re susceptible now because of the additional stresses,” says Hargreaves, who sees habitat loss as a much larger problem for amphibians around the world.
According to the Calgary Wetland Conservation Plan, Calgary had lost an estimated 78 per cent of its pre-settlement wetlands by 1981. Today, that estimation stands at 90 per cent.
In 2004, Calgary became one of the country’s first municipalities to adopt a no-net-loss wetland protection policy. If a wetland area can’t be protected in place, developers are required to compensate by re-establishing the wetland in a better-connected and more sustainable system.
According to Chris Manderson, natural area planning co-ordinator for the City of Calgary, wetland restoration can be done successfully if planned properly and done in the right location. However, the process isn’t fast or cheap. Lake Hawk Park, Calgary’s first wetland restoration project set to begin this winter, may cost a couple of million dollars and take at least three to five years to establish five to 10 hectares of land. “In my view, [wetland restoration] should always be your last option,” says Manderson. “You’re better off to protect something in the first place rather than try to rebuild it.”
“Frogs are affected by every single environmental problem people come up with,” says Hargreaves. “[Yet] people really have the ability to make small changes in their lifestyle that are actually significant for amphibians.”
According to Hargreaves, forgoing the use of pesticides and using non-toxic soaps are ways people can reduce their environmental impact in a way beneficial to frogs.
The Calgary Zoo will celebrate Earth Day (April 22) early with its Party for the Planet event. Activities will include frog games and lectures in the conservatory to raise awareness about Year of the Frog. The event takes place Saturday, April 19 from 10 a.m. to 4 p.m. Regular admission applies.
