THAT TIME FORGOT
Graduate student uncovers Montana amphibians
By HOLLY FOX
What class of organisms plays a critical role in transferring energy up the food chain, shapes terrestrial and aquatic communities, and serves as an important bioindicator of environmental quality? The answer is amphibians — cold-blooded vertebrates such as frogs, toads, newts and salamanders that begin life submerged as tadpoles and grow up to live not only in the water, but on land as well.
Sure, amphibians sound important, and the ability to be at home in a pond or on a grassy knoll is impressive, but as one famous amphibian Muppet said, "It's not easy being green" — or any other color, it seems.
In fact, some amphibian populations around the world and in Montana are in decline or have disappeared all together. Because of their amphibious lifestyle, they often slip through the cracks when it comes to wildlife management — are they the responsibility of terrestrial or aquatic wildlife managers? But these multifaceted animals are getting some serious attention from a UM student who has devoted his time at the University to inventorying the amphibious populations of the Big Sky state and to documenting the life story of the Columbia spotted frog, the state's most common frog species.
Bryce Maxell, who is earning a doctorate degree in fish and wildlife biology at UM, says he decided to study amphibians when he realized how little is known about them, specifically in Montana. "I guess I was looking for a niche that needed to be filled where my efforts might be most meaningful," he says.
"Within the last decade a number of people who study amphibians and reptiles have noticed declines all over the world," Maxell says. "In some cases it's pretty straightforward what the causes are, but there are a lot of cases in which they haven't been able to identify what is causing the declines — they just don't know what's going on."
identify the causes, Maxell says, many researchers are conducting
short-term experiments to determine the effects of certain
environmental changes on
"They might expose eggs to ultraviolet radiation or larvae to some sort of chemical," he says. "But their results aren't very meaningful because they don't really understand the demography of the species."
Part of Maxell's research is dedicated to studying the life histories of Columbia spotted frogs to obtain basic information about their life cycles and habitats. "Researchers don't know what the typical survival rates are for these frogs at each life history stage," he says. "So part of my research is directed toward documenting the background demography of the survival rates on the eggs, the larvae, the newly metamorphosed frogs and the adults, both male and female.
"I want to provide agencies in Montana with the first scientifically defensible overview of the status of amphibians across the state and add as much to the body of knowledge about the demography and general biology of these species as I can," he says.
Research runs in the Maxell family — Bryce's father studied small mammals in Wyoming for his Ph.D. research. "From an early age I was surrounded by a wide variety of domesticated and wild animals," Maxell says. "We spent a lot of time camping in the summer and dogsledding in the winter when I was growing up, and my dad knew the names of almost every plant and animal, which made me interested in wildlife since I was very young."
Maxell studies the frogs in three study basins — two in the Bitterroot Mountains and one in the Cabinet Mountains.
The three basins have varying numbers of water bodies, which have varying numbers of fish.
"The basins in the Bitterroot have multiple lakes, ponds and water systems, on the order of 15 to 20 ponds or lakes," Maxell said. "One basin has a lot of fish in the lakes and the other is basically fishless. The third basin in the Cabinets is just a single pond with no fish. I wanted to look at interactions between local amphibious populations in ponds with and without fish in a couple of basins, and then study the populations in a single control pond.
top of that, not all the ponds provide the habitats they
need year-round — some are only good for overwintering,
some are only good for breeding — so we are studying
the survival rates in conjunction with the use of seasonal
Maxell and his researchers count the number of eggs at each pond, cage the eggs, then come back later to count the number of hatchlings that resulted from those eggs. They return to get an estimate of the metamorphosed animals, and again to estimate the number of adult frogs. This process has been going on for four years.
"So far we have marked around 12,000 animals in all three basins combined," Maxell says. "We combine the survival rate information with habitat information to see if there are differences in survival rates based on fish, solar exposure, elevation, vegetation, things like that. For example, last spring was very cold and there was simply not enough growing season for the tadpoles to metamorphose and about 85 percent of the tadpoles at my sites froze."
As ectotherms, amphibians control their body temperature behaviorally — by sitting on a hot rock to keep warm or getting in the wind to cool off. This also means they need a certain thermal environment, warm weather, to grow and develop.
Maxell devotes the rest of his research to a broad-scale inventory of amphibians in Montana. "Right now we are inventorying in western Montana, but it is in the process of be-coming statewide," he says.
Maxell and his inventory crew divided the western part of the state into nine sampling areas from which they randomly selected several watersheds. The crew then visits every single body of standing water in that watershed they can find on maps, photos or by word of mouth and inventories what amphibians and aquatic reptiles are present.
Why? "Even for the most common amphibian in western Montana we don't have very good information about where they live and how long," Maxell says. "If we don't have good basic information now about what species live where, how will we know if their status has changed in 20 years? It's the same issue for the landscape — if you don't know the status of the landscape now, how will you be able to assess it later?"
The process is long and physically draining, says Maxell, but the results are rewarding.
"The most challenging part of my research is the long hours dealing with massive amounts of data that is sometimes not that exciting to deal with," he says. "But the data is essential, and it is really rewarding to find species where they have never been reported before and to provide state and federal agencies with information that will be used to ensure that these species are more properly managed and protected."
The inventory information Maxell is compiling will be useful for years to come as a key to understanding changes in Montana's landscapes and species. For example, future researchers or wildlife managers will be able to use this infor-mation to determine into which habitats or elevations they should reintroduce a species.
Maxell plans to finish his Ph.D. work at UM next spring. What's next?
An outdoor enthusiast who swam competitively in high school and as an undergraduate at the University of Puget Sound in Tacoma, Wash., he looks forward to a little time off from his strenuous research work. "Canoe and backpacking trips are my favorite activities, and I love swimming and bicycling to stay physically fit," he says. "On the professional side, my career goal is either to work as a zoologist/ecologist for a non-government conservation-oriented organization or government agency where my research efforts would be applied to species management, or to teach biology and ecology and conduct research at a smaller four-year university."