Where have the frogs gone?
Unfortunately, it’s not surprising to hear about yet another species on the brink of extinction. Frog populations around the world are known to be declining at alarming rates, as are other amphibian species. More than half of the world’s amphibians are threatened with extinction, and nearly 200 species have disappeared since the 80’s. This is not normal: amphibians naturally go extinct at a rate of about one species every 250 years.
Losing frogs is of concern because they serve a variety of purposes in maintaining healthy ecosystems. Frogs help control insect populations, tadpoles keep algae growth in check, and both are important food sources for a variety of species in the food chain.
The Northern Leopard Frog was once the most common amphibian in North America. However, due to many contributing factors, their numbers have dropped dramatically, with the BC population being impacted more heavily than anywhere else. Although the decline began in the 60’s, it was not until the 1990’s that biologists realized just one population remained. The very hospitable habitat in the Creston Valley wetlands in BC is the last home for the Northern Leopard Frog.
Biologists do not cite any one cause for the huge loss of the Northern Leopard Frog: habitat loss, disease and road mortality were and still are the greatest challenges this frog is facing. As if this were not enough, the Northern Leopard Frog also suffers from increased predation by introduced non-native species, such as largemouth bass and yellow perch, to name a few. It shouldn’t be surprising that currently the Northern Leopard Frog is listed as endangered.
Recovery efforts for this frog began in 2001 at the Creston Valley Wildlife Management Area. The focus of these efforts was a captive breeding and reintroduction program in conjunction with extensive inventory and monitoring of this lone population. Over the next four years, thousands of Northern Leopard Frogs were raised and released into the wetlands. Unfortunately, very few seemed to be surviving: biologists were finding at most nine egg masses each year, which suggests just nine breeding pairs…not enough to support a viable population.
The situation seems brighter these past two years for the Northern Leopard Frog, with record high numbers of egg masses being found. There have been so many in fact, that eggs and tadpoles have been moved from the Creston population to one of the frogs’ other historical ranges in the East Kootenays. This is very good news, however, there is still a long way to go.
One issue of concern that may continue to threaten the Northern Leopard Frog is the presence of a fungal disease . This fungus has already been responsible for the decline or extinction of at least 200 frog species around the world in the last 30 years. The spread of the fungus is primarily from human movement between water bodies. Boots and equipment accidently pick up fungus from one place and deposit it into another. Preventing the spread can be accomplished by spraying down all equipment with a solution of 10% bleach before setting foot in another body of water. This will help get rid of those unwanted microscopic killers.
Hopefully the results of the past two years will become a continuing trend for the lone provincial population of Northern Leopard Frogs. Everyone benefits when ecosystems are healthy, and insects are kept under control.
You can make a difference by becoming a citizen scientist with the BCFrogWatch program (http://www.env.gov.bc.ca/wld/frogwatch/).
Sarah Meunier and Khaylish Fraser are second-year Recreation, Fish and Wildlife students at Castlegar’s Selkirk College.