Effects of Fire Suppression and Exclusion on Boreal Toad (Bufo boreas) Populations

Principal Investigators:
Blake Hossack, USGS-NRMSC and Aldo Leopold Wilderness Research Institute
P.S. Corn, PhD, USGS-NRMSC and Aldo Leopold Wilderness Research Institute

Collaborators: Greg Guscio and Dr. Lisa Eby, University of Montana; Eric Simandle and Dr. Richard Tracy, University of Nevada-Reno; Dr. Stephen Diamond, EPA

Research Objective: Evaluate the hypothesis that fire suppression and exclusion could cause decline of the boreal toad in the northern Rocky Mountains.

Update:
Breeding pond surveys were continued in 2003. Most of the new toad breeding sites established in 2002 were vacant this year, but some new populations were established in 2003. Genetic work is underway at the University of Nevada-Reno. Sampling to compare environments (UV-B penetration, water temperature) in burned and unburned wetlands was initiated in 2003. Studies of habitat use by adults will begin during spring 2004.

Background:
Amphibian declines have occurred in the western US at a disproportionate rate. Coincident with many of these declines have been thickening forests from nearly 100 years of forest policy that supported fire suppression and exclusion. Studies in the eastern US show that forest succession and closure of canopy over breeding ponds can lead to the decline of some species. The relationship between forest structure and lentic amphibians has not been investigated in the western US.

Recent evidence from Glacier NP has linked B. boreas with wildfire. We documented increases in the number of breeding sites after wildfires in 1999 and 2001. Following the 2001 Moose Fire, 10 of 43 wetlands that had been surveyed or were dry prior to the fire were colonized. Toads had not previously been found breeding in the area during 1999-2001, and no wetlands outside of the burned area were colonized in 2002. Similar to our observations in Glacier NP, multiple new B. boreas breeding sites were found 2 years after a large wildfire in central Idaho where they had been rare during the previous 11 years (C. Peterson, personal communication). B. boreas is often associated with disturbed habitats, and wildfire is a landscape-scale disturbance that creates habitat conditions that are seemingly preferred. In conjunction with our ARMI monitoring work, we are currently conducting a study of the distribution of amphibian populations across a chronosequence of fires on the west side of Glacier NP. However, monitoring alone will not provide explanations as to why adult toads seem to quickly colonize burned habitats, where the colonists came from, or what characteristics of burned wetlands make them preferable to unburned wetlands. We plan to use a combination of adult habitat use and its implications for thermo- and hydroregulation, microsatellite allele data, and characteristics of burned wetlands together with continued broad-scale surveys to evaluate the hypothesis that fire suppression could cause decline of B. boreas.


ARMI > Additional Projects Effects of Fire Suppression and Exclusion on Boreal Toad (Bufo boreas) Populations Principal Investigators: Blake Hossack, USGS-NRMSC and Aldo Leopold Wilderness Research Institute P.S. Corn, PhD, USGS-NRMSC and Aldo Leopold Wilderness Research Institute Funding Source: Amphibian Research and Monitoring Initiative (ARMI) Collaborators: Greg Guscio and Dr. Lisa Eby, University of Montana; Eric Simandle and Dr. Richard Tracy, University of Nevada-Reno; Dr. Stephen Diamond, EPA Research Objective: Evaluate the hypothesis that fire suppression and exclusion could cause decline of the boreal toad in the northern Rocky Mountains. Update: Breeding pond surveys were continued in 2003. Most of the new toad breeding sites established in 2002 were vacant this year, but some new populations were established in 2003. Genetic work is underway at the University of Nevada-Reno. Sampling to compare environments (UV-B penetration, water temperature) in burned and unburned wetlands was initiated in 2003. Studies of habitat use by adults will begin during spring 2004. Background: Amphibian declines have occurred in the western US at a disproportionate rate. Coincident with many of these declines have been thickening forests from nearly 100 years of forest policy that supported fire suppression and exclusion. Studies in the eastern US show that forest succession and closure of canopy over breeding ponds can lead to the decline of some species. The relationship between forest structure and lentic amphibians has not been investigated in the western US. Recent evidence from Glacier NP has linked B. boreas with wildfire. We documented increases in the number of breeding sites after wildfires in 1999 and 2001. Following the 2001 Moose Fire, 10 of 43 wetlands that had been surveyed or were dry prior to the fire were colonized. Toads had not previously been found breeding in the area during 1999-2001, and no wetlands outside of the burned area were colonized in 2002. Similar to our observations in Glacier NP, multiple new B. boreas breeding sites were found 2 years after a large wildfire in central Idaho where they had been rare during the previous 11 years (C. Peterson, personal communication). B. boreas is often associated with disturbed habitats, and wildfire is a landscape-scale disturbance that creates habitat conditions that are seemingly preferred. In conjunction with our ARMI monitoring work, we are currently conducting a study of the distribution of amphibian populations across a chronosequence of fires on the west side of Glacier NP. However, monitoring alone will not provide explanations as to why adult toads seem to quickly colonize burned habitats, where the colonists came from, or what characteristics of burned wetlands make them preferable to unburned wetlands. We plan to use a combination of adult habitat use and its implications for thermo- and hydroregulation, microsatellite allele data, and characteristics of burned wetlands together with continued broad-scale surveys to evaluate the hypothesis that fire suppression could cause decline of B. boreas. Back To Top
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Effects of Fire Suppression and Exclusion on Boreal Toad (Bufo boreas) Populations

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