The story of Coastal Douglas-fir forests: All about amphibians
Critical habitats like small wetlands and mature forests need better protection for all the species that depend on them.
Oftentimes aquatic habitats protection exclusively emphasizes the importance of maintaining fish populations. Though protecting native fish species is inarguably important, this approach to conservation often overlooks amphibian populations. In this article, Elke Wind of E. Wind Consulting in Nanaimo, BC describes the amphibian species common to the Coastal Douglas-fir biogeoclimatic zone; identifies their preferred habitat types; and makes recommendations for strengthening amphibian protection.
What are some of the common amphibian species you might expect to encounter within the Coastal Douglas-fir biogeoclimatic zone?
The most commonly encountered species in our area is the Pacific Treefrog (Pseudacris regilla). Mainly because it is the only native amphibian species in this area that has an audible call, and it can cohabitate relatively well in and around rural and semi-urban properties. The call of the Pacific Treefrog is a sure sign that spring is on its way. It sounds a bit like a fingernail being pulled down a comb.
The other two frog species, the Red-legged Frog (Rana aurora) and Western Toad – yes, toads are technically frogs (Anaxyrus boreas), and the six salamander species we have here are relatively, or completely, quiet during the breeding season. If you’re moving wood in a wood pile, or debris from your yard, you may come across a salamander using it for cover. The two non-native frog species, the American Bullfrog (Lithobates catesbeianus) and the Green Frog (Rana clamitans), are quite common in some areas, especially in human-made ponds (e.g., dugout ponds, stormwater ponds, and golf course ponds), and their calls are quite loud in summer.
What sorts of habitats on the Gulf Islands and Southern Vancouver Island are most vital to maintaining a healthy amphibian population?
Six of the nine native amphibian species in our area breed in water, such as ponds, wetlands, lakes, and very slow-moving streams. The majority of these amphibian species can breed in seasonal or temporary ponds and wetlands, which contain fewer predators than permanent water bodies. However, these small, temporary ponds and wetlands have no legal protection and are often lost to development. Even where there is some riparian protection of these aquatic habitats, it is only effective for amphibians if significant upland forested habitat remains, as these species spend most of their time on land outside of the spring breeding season, including overwintering underground. Landscapes that contain a combination of mature forest cover and a variety of aquatic habitats of different sizes, depths, and hydroperiods offer the best habitat for meeting all of the annual life-history requirements of our native amphibian species.
Are there any amphibian species endemic to this region?
In BC, the Wandering Salamander (Aneides vagrans) only occurs on Vancouver Island. Interestingly, populations of this species also occur in Oregon, not in Washington State. There are a number of theories as to why this species has this fragmented range, but nobody really knows why.The Wandering Salamander is a fully terrestrial salamander, meaning it lays its eggs on land, not in water.
Terrestrial salamanders are very interesting and unique because they do not have lungs (they breathe through their skin), they have relatively small home ranges (some may spend their entire lives within one large, old-growth log), and their young emerge from eggs looking just like their parents (they do not have a bi-phasic life history like the aquatic-breeding amphibians).
Is population decline a significant worry in this region? If so, are there any species of particular concern? What are some of the major drivers of population decline?
Although there are anecdotal observations of some amphibian populations disappearing from Vancouver Island, we do not have any documented declines of amphibian species in the area. Nobody has been monitoring local amphibians, especially the aquatic-breeding species, in the systematic way required to document a decline. Monitoring the status of amphibian populations takes years of data collection (10+) and a lot of effort and resources (i.e., money). Aquatic-breeding amphibian populations fluctuate quite extensively from year to year in relation to climatic conditions, so many years of data collection are needed to detect any trends. Having said that, individual populations have been lost where there has been a permanent conversion of natural habitats to development (i.e., forests to concrete) because, as mentioned above, amphibians live most of their lives on land outside the aquatic breeding season.
Habitat loss and fragmentation as a result of urban and rural development, and ever-expanding road networks, are major threats for native amphibian species. As wetlands are drained and infilled, forests are replaced with urban development, and the distances between these critical habitats becomes greater and separated by roads, the more difficult it becomes for our native amphibian species to survive.
What are your recommendations for conserving amphibian numbers in this region? Is there anything individuals can do to help stabilize populations in decline?
I would like to see greater recognition regarding the value and importance of small wetland habitats, even small, seasonal, temporary ponds. We place a lot of emphasis on the protection of aquatic habitats that have or support fish. But amphibians are basically fish food. They do not want to breed in permanent aquatic habitats that contain fish. As such, amphibians need their own protected aquatic habitats, as do many invertebrates that are also on the menu of most fish species.
Another major issue for amphibians is roads. Well, actually not the roads themselves, but the vehicular traffic on the road that kills amphibians during their annual migrations—amphibians make multiple migrations each year to and from aquatic habitats into upland areas (e.g., adults in the spring, juveniles in the summer/fall). Ideally, we would slow down or halt road expansion (i.e., fragmenting more habitat), and we would be driving less (carpooling, using bikes, working from home). Thousands, if not millions, of amphibians are killed on our roads each year during their spring and fall migrations. If folks living in rural and semi-urban areas near wetlands and forests could avoid driving on mild, wet evenings in the spring and fall (i.e., around and after sunset), they might be saving hundreds to thousands of migrating amphibians.
Are there any policies you’d like to see improved that might help to better protect amphibian populations in the CDF or in BC in general?
Critical habitats like small wetlands and mature forests need better protection. I think it should be much more difficult for developers and landowners to drain or infill wetland habitats and to remove forest cover, and/or there needs to be greater incentives for protection. Although we can and do build wetlands, studies have shown that they are not the same as natural wetlands—it’s very difficult to replicate nature.
I would also like to see efforts to green new developments and roadways. That is, new developments should have to consider landscape context (i.e. cumulative effects) in their designs, including considerations of wildlife movement patterns to protect animal migration routes. Green developments would retain natural habitats and species (versus removing forest cover and sparsely replanting with horticultural varieties), maintain natural connective habitat corridors (in both upland and riparian areas), and utilize techniques such as underpasses and elevated roadways to avoid fragmenting natural habitats and interrupting movement pathways.
About Elke Wind
Elke Wind obtained her M.Sc. in Conservation Biology at UBC in 1996 and her status as a Registered Professional Biologist in 2003. She owns E. Wind Consulting and has worked as a self-employed contract biologist since 2002 and has more than 25 years of experience studying amphibian populations. She specializes in the habitat associations and requirements of amphibian populations in relation to impacts of timber harvesting, rural and urban development, linear infrastructure projects (e.g., roads, trails, pipeline right of ways), and non-native species. She co-authored the provincial Best Management Practices for amphibian salvage operations and has designed and conducted salvages for lentic and lotic amphibian species. In addition, Ms. Wind has built or restored more than 20 wetlands and written numerous amphibian related reports for government, species recovery teams, and non-profit organizations including Best Management Practices, status reports, and chapters within amphibian field guides. Ms. Wind has dedicated many volunteer hours towards community and non-profit groups such as the BC NatureKids, the Society for Northwest Vertebrate Biology, and Northwest Partners in Amphibian and Reptile Conservation.
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