On Sunday, April 20th, 50 people gathered at the Beaver Meadows Visitor Center auditorium for the final talk in the bi-weekly Winter Speaker Series event. Jonathan Lewis, the conservation biology program manager for Rocky Mountain National Park, presented “Efforts to Restore Boreal Toad Populations in RMNP,” to share monitoring updates and current restoration strategies with the public.
Being one of four native amphibian species currently in the park, boreal toads live in wetland ecosystems between 8,000-12,000 ft in elevation. They can be identified by their brown and black skin and distinct yellow line running down their back. Females can be twice as large as their male counterparts since they carry and lay around 3,000-8,000 eggs.
The boreal toad has been listed as an endangered species in Colorado since 1993 and is absent from most of its historic range. Rocky’s Conservation Biology Program currently monitors five active breeding sites in the park, compared to the 20 breeding sites documented in 1915 when the park was founded. The boreal toad population has declined dramatically over the past 30 years in Rocky Mountain National Park due to a disease called chytrid fungus.
Chytrid fungus is a fungal pathogen that causes a fatal skin disease with a high mortality rate when boreal toads are infected. This fungus negatively affects amphibious populations by destroying the keratin in their skin, which reduces its ability to regulate the skin’s functions to breathe and stay hydrated (NPS.gov).
Since the fungus was first detected in Rocky in the late 1990s, park staff and other agencies have worked hard to develop possible solutions to combat the fungus and restore Rocky’s boreal toad population.
A large component of fighting this infection is collaboration with other agencies and research groups. “In wildlife conservation, one team can’t do it all,” said Lewis. “It takes strong partnerships between agencies and a lot of field work to get this done.” Rocky Mountain National Park currently collaborates with Colorado Parks and Wildlife, the Denver Zoo, Rocky Mountain Conservancy, US Geological Survey, and Colorado State University to share information and new ideas on how to preserve the species.
Monitoring boreal toads in the park is a huge component of the conservation effort. Seasonal field staff visit breeding ponds to keep track of individual toads and the spread of chytrid fungus. At each breeding site, a group of dedicated amphibian technicians and volunteers will methodically search the area for boreal toads by conducting a visual encounter survey. For every toad caught, the technicians will measure their length and weight, conduct disease testing, take an identifying belly photo (similar to a thumbprint signature), and in some cases, insert a small passive implant transmitter (PIT tag) into the toad to be part of a mark-recapture study; a method to estimate the population size and survival rates.
Another important strategy in place to reestablish boreal toad populations is reintroduction. The process begins with collecting a small percentage of boreal toad eggs from the park and raising them in Colorado Parks and Wildlife hatcheries. “What we find is when we raise them in a hatchery setting, it exponentially increases their survival to reaching their terrestrial life stage,” said Lewis. Hatcheries protect their development when they are most vulnerable by removing predators like aquatic insects. This allows almost all of the eggs to develop into tadpoles before being released back into the wild.
Reintroduction days are a huge effort, requiring a large team of park employees, interns, collaborators from universities, and volunteers. The tadpoles are transported from the hatchery in large plastic bags, which are secured inside backpacks of those hiking to the reintroduction site. The team records data as they release the tadpoles into their new home followed by weeks of monitoring until they morph into their terrestrial stage and leave the pond. The hope is that a portion will survive and mature to adults that return to the pond ready to reproduce.
There are steps you can take to facilitate the success of reintroduction efforts. If you are lucky enough to see a boreal toad in Rocky Mountain National Park, do not pick it up. Take a photo of the toad and send it to romo_information@nps.gov with information on the sighting location. To prevent the potential spread of chytrid fungus and other aquatic diseases, follow park disinfect guidelines for waders and fishing equipment with a bleach-water solution before fishing or exploring wetlands in the park to prevent the potential spread of chytrid fungus and other aquatic diseases. For aquatic disinfection protocol please visit Fishing in RMNP (U.S. National Park Service)
We would like to thank Jonathan Lewis for sharing his time and expertise. To learn more about boreal toad research in Rocky Mountain National Park, visit NPS.gov for additional information and resources: https://www.nps.gov/articles/000/boreal-toad-research-in-rocky-mountain-national-park.htm.