Amphibian Research and Monitoring Initiative: Rocky Mountain Region

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The Rocky Mountain Region of Amphibian Research and Monitoring Initiative (ARMI) encompasses Montana, Wyoming, Colorado, and New Mexico. Two USGS Science Centers initiate and develop ARMI projects in this region. Investigations at NOROCK are headed by Dr. Blake Hossack. Investigations at the Fort Collins Science Center (FORT), Colorado, are headed by Dr. Erin Muths. The ARMI program is based on a 3-tier, pyramid approach; extensive broad scale sampling, mid-level sampling and intensive sampling and research at apex sites. We use a variety of methods. Information from surveys in the Rocky Mountains is used to determine the occupancy of species of amphibian in a target area. These data are compiled at the national level where the information will be used in designing new surveys and framing hypotheses to be tested about amphibian presence, amphibian decline, and other related issues such as deformity and disease. The Rocky Mountains are not rich in species diversity, but information from this region is critical because much of the land in the Rocky Mountains is relatively pristine and protected, yet the decline of amphibians in such areas is still largely unexplained.

Boreal toad (Bufo boreas) mating ball, Bridger-Teton National Forest, Wyoming.

Boreal toad (Bufo boreas) mating ball, Bridger-Teton National Forest, Wyoming.Public domain

The Department of the Interior's Amphibian Research and Monitoring Initiative (ARMI) is designed to determine where populations of amphibians are present; to monitor specific populations and to investigate potential causes of decline and deformity. 

RARMI scientists conduct research into factors that may affect the distribution and abundance of amphibian populations. Current
projects address the effects of disease, fire, and climate change.

Disease:

The pathogenic amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) is a leading cause of global amphibian declines. Recent findings by scientists and collaborators include:

  • Bd is commonly found on pond-breeding amphibians and in their habitats throughout the Rocky Mountains, but the sudden and severe die‐offs of amphibians seen elsewhere have not been detected.
  • A seven state, nation-wide survey of stream-dwelling amphibians found Bd largely absent from these species and habitats.
    Populations of boreal toads in Montana and Wyoming with Bd had lower annual survival of adult males than a population in Colorado that was Bd free.
  • A Bd strain from Wyoming is as pathogenic to juvenile boreal toads as a strain from Colorado, but toads from Wyoming selected drier sites within experimental enclosures and survived longer than toads from Colorado.

Fire:

The northern Rocky Mountains have experienced large wildfires during the past decade, including Glacier National Park (GNP) where considerable data on amphibian occurrence had been recently collected. This allowed scientists to compare populations before and after the fires. Key findings include:

  • Abundance of young Rocky Mountain tailed frog (Ascaphus montanus) tadpoles was reduced in burned streams.
  • Occupancy of breeding sites by long-toed salamanders (Ambystoma macrodactylum) and Columbia spotted frogs (Rana luteiventris) did not differ before and after fire (Fig. 5).
  • Breeding sites of boreal toads increased in burned areas, and adult toads preferred to use severely burned areas in the year after fire.

A current study in GNP and the adjacent Flathead National Forest is examining the sub‐lethal effects of fire on Rocky Mountain tailed frogs and long-toed salamanders by comparing population size, body condition, and disease state of amphibians in unburned habitats to burned sites and sites that have been salvage logged, the practice of logging trees in forest areas that have been damaged by wildfire.

Climate Change:

Climate change and its implications for amphibians has long been an emphasis of RARMI scientists. Research topics have included the effects of ultraviolet (UV) radiation, long-term trends in breeding phenology (when breeding occurs each year), and responses of populations to weather conditions. Some of the results include:

  • There was little relationship between UV and occurrence of amphibians at GNP or other western parks. Damaging amounts of UV do not penetrate deeply into most water used for breeding by amphibians.
  • Montane amphibians breed earlier in years with low winter snow packs, exposing their eggs to lower doses of UV. Despite thinning stratospheric ozone and increasing UV radiation, annual variation in phenology results in no increase in UV for amphibian embryos.
  • A long-term population study by University of Montana graduate students found that annual survival of Columbia spotted frogs was higher after winters with less snowfall, suggesting some benefits of climate change for montane amphibians.

Current research is investigating the consequences of climate change on the Rocky Mountain tailed frog, the dominant vertebrate in small streams in the northern Rocky Mountains. Effects of climate change predictions pose direct and indirect threats to species dependent on cold streams through increased summer temperatures, reduced summer flow and decreased length of permanent stream channels, and increased risk of wildfires. NOROCK scientists are expanding their observations of amphibian breeding phenology at several new sites in Montana and Wyoming using automated recording units (Fig. 6), which make digital recordings of the soundscape at specified intervals, allowing detection of amphibian species that produce breeding calls.

 

Apex Sites:

Apex sites are specific sites or groups of sites where research is being conducted. Research is aimed at answering particular questions about amphibian decline or gathering more detailed information about the dynamics of a particular amphibian population. More detailed information describing RARMI's Apex sites can be found under Related Content.

Fort Collins Science Center

In the southern Rocky Mountains researchers focus on 3 sentinel sites in Colorado, and have worked at 4 mid-level sites in Colorado and Wyoming. As work progresses at these sites we are collaborating with the National Park Service Inventory and Monitoring Program. To meet goals of this NPS program we included reptiles in our surveys at National Parks and Monuments.

Mid-level sites -- Colorado

  • Rocky Mountain National Park - ongoing
  • Great Sand Dunes National Monument and Preserve - completed
  • Florissant Fossil Beds National Monument - completed
  • Bent's Old Fort National Historic Site (inventory) - completed

Mid-level site - Wyoming

  • Seedskadee National Wildlife Refuge (SNWR)

 

Northern Rocky Mountain Science Center:

Researchers have established 4 apex sites in Montana and Wyoming and 11 mid-level inventory and monitoring areas located in Montana, Idaho, Wyoming and North Dakota.

Mid-level study areas -- Montana

  • Glacier National Park - ongoing
  • National Bison Range - terminated
  • Lost Trail National Wildlife Refuge - ongoing
  • Swan River National Wildlife Refuge - terminated
  • Red Rocks NWR - terminated
  • Medicine Lake National Wildlife Refuge - terminated

Mid-level study areas -- Idaho

  • Grays Lake NWR - terminated

Mid-level study areas -- Wyoming

  • Yellowstone NP - ongoing
  • Grand Teton NP - ongoing
  • National Elk Refuge - ongoing

Mid-level study area - North Dakota

  • Theodore Roosevelt NP - suspended

Grant-Kohrs Ranch National Historic Site is also surveyed in cooperation with the National Park Service Inventory and Monitoring Program. Here researchers collaborate with Bryce Maxell, University of Montana doctoral student, on his inventory of amphibian populations on US Forest Service lands in western Montana and surveys of historic boreal toad (Bufo boreas) sites.