On the trail of the tailed frog

🕔Apr 07, 2011

The coastal (or Pacific) tailed frog, Ascaphus truei, is a small frog that breeds in clear, cold, fast-flowing streams and creeks. Some biologists and professional foresters see this little frog as a biological indicator of overall habitat health, meaning its presence indicates a healthy forest and a healthy stream.

The coastal tailed frog is unique to the west coast of North America and its presence in our cold waterways represents the most northern reaches of the species. The Kalum Forest District, centred around Terrace, is the epicentre for coastal tailed frog distribution. The frog is not found North of the Nass River and rarely on the North Coast because of greater torrents. The Kalum District, specifically the Skeena West side, has an abundance of fast moving streams and cold-water creeks feeding the Skeena River. “The streams in the Skeena Region are more protected than on the North Coast, so are ideal habitat for the coastal tailed frog,” states Anne Hetherington, Regional Endangered Species Specialist with the Ministry of Natural Resource Operations.

Little Frog
A Prince Rupert Forest Region report states, “in taxonomic terms the tailed frog is widely separate from other amphibian species, occupying a unique and ancient evolutionary branch.” Hetherington agrees, and further explains that the coastal tailed frog is the oldest frog, evolutionarily speaking, dating back to Pangea before the continents broke apart.

The frog’s uniqueness is reflected in unusual physical characteristics. Unlike other frog species, a male tailed frog deposits sperm directly into an adult female frog via his ‘tail,’ actually an appendage adapted to ensure the sperm doesn’t wash away. The female stores the sperm inside her body until the following summer, then lays the fertilized eggs in a stream. These frogs also have a very long maturation stage: it can take up to six years for them to develop through the tadpole stage. Adults burrow under logs in cold, wet or damp areas of the forest and can live up to 20 years. They are found in or near their home streams year-round but are seldom seen, coming out to hunt insects at night or during wet weather. They are quick to hide under debris in response to any disturbance in their environment.

“These amphibians are cold-water specialists. They have survived by using parts of streams that other animals don’t use and where they have few predators and competitors,” says Hetherington. The water they need is cold and clear; it has to be fast-moving and with no silt. Interestingly, they have no ears, an adaptation to life in streams that are extremely noisy.

These small frogs, measuring anywhere from two to five centimetres at maturity, depend upon the cool, damp conditions that the Skeena tributaries provide; the frequent cold creeks, the steep slopes that make them fast-moving, the tall thick trees of the Coastal Western Hemlock and interior Cedar Hemlock forests, the boulders and shady undergrowth.

A 1996 study published by the Prince Rupert Forest Region concluded that, “logging disturbance can greatly influence creek characteristics and abundance of tailed frog tadpoles.” The three researchers found that road-building across streams and creeks and logging in a watershed or an upper section of a stream increases the water temperature and deposits fine organic matter into the waterway. The tadpoles’ chances of survival decrease as their stream is muddied, as the temperature increases and the water flow is reduced. Those streams and creeks that did not have road crossings and were not logged up to the edges, that instead had a “buffer” (an area of intact forest running along beside the stream), remained cold and clear.

“When you change from a natural to a managed landscape,” says Hetherington, “you need to keep enough best-quality habitat, in the most strategic places, over the long term so populations are large and connected enough to survive and continue to be a part of the unique ecosystem of our region.”

A little law
It’s difficult to wade through all the current provincial legislation in search of references to a small frog in northern BC’s mountains. But, within the documents and plans that govern forests and lands, there appears to be a degree of protection offered to the coastal tailed frogs in our north.

The Forest Planning and Practices Regulation (FPPR), section 7 (1) states, “the objective set by government for wildlife is, without unduly reducing the supply of timber from British Columbia’s forests, to conserve sufficient wildlife habitat in terms of amount of area, distribution of areas and attributes of those areas…”

The province of BC has identified the coastal tailed frog as a species of special concern, a blue-listed species. Recognizing that the frog is susceptible to human activities or natural events, the Kalum Land and Resource Management Plan and the Kalum SRMP have identified special areas for the frog. According to a BC government website, these areas are currently referred to as Wildlife Habitat Areas (WHA) and are meant to “...ensure that there are legacy areas where stream stability, maintenance of water temperature, riparian habitat and microclimate, and coarse woody debris for adult frog dispersion are the focus.” The boundaries of WHAs came after two years of research where biologists, herpetologists and geomorphologists researched forest watersheds and inventoried frog populations.

The little frog has ten WHAs spread out across the approximately 3.8 million hectares in the Kalum District. This designated habitat area for the frog totals 675 hectares of the Kalum’s 81,000-hectare timber-harvest land base.

“These creatures have natural challenges with their dispersal,” explains Hetherington, meaning that, unlike birds, they can’t fly across clearcuts. They have to hop. “We must try to ensure that they can link up with other areas so they have a chance.”

The Deputy Minister of Environment’s actual legal Order shows that logging may still occur within a WHA and road-building can still take place, although stream crossings require a Minister’s exemption. These WHAs are the legal minimum amount of land that is protected for the frog. It is hoped that logging companies will follow “best management practices” in their cutblocks and minimize their activity in a WHA and minimize disturbance in other areas that are suitable tailed-frog habitat.

Tailed frogs today
In recent years the coastal tailed frog has been found further inland than previously thought. Also, BC Timber Sales has recently identified areas that are likely to contain coastal tailed frogs. They have initiated studies and altered their cutblocks to preserve potential frog habitat. Biologists are currently interested in what the adult frogs do; where they live and how wide their range is during their unusually long lifespan. The WHAs will be visited this summer and frog numbers recorded.

This summer the frogs will be hopping around in damp areas of the forest, breeding in the cold streams, their tadpoles clinging to rocks in the swift, clear water with their mouth suckers. The Wildlife Habitat Areas offer a step in the right direction, towards the long-term survival of the species. But, recognizing that the little frog is blue-listed, seen as susceptible to human activities such as logging and natural events such as landslides, shouldn’t more WHAs be established, shouldn’t less activity be allowed in a WHA? Are these WHAs just a tailed-frog-hop worth of protection?

If these frogs have been here since before the mountains, we have a responsibility do everything we can to keep them here.