Habitat Assessment for Re-establishing Extirpated Cascades Frog in Lassen Volcanic National Park
Project ID: P17AC01723
Federal Agency: National Park Service
Partner Institution: Washington State University
Fiscal Year: 2017
Initial Funding: $29,375
Total Funding: $29,375
Project Type: Research
Project Disciplines: Biological
National Park: Lassen Volcanic National Park
Principal Investigator: Piovia-Scott, Jonah
Agreement Technical Representative: Magnuson, Michael
Abstract: A. Background
The Cascades frog (Rana cascadae) is one of two frog species known to historically occur in Lassen Volcanic National Park (LAVO). The Cascades frog is a highly visible and charismatic species that historically occupied lakes and wetlands throughout the Cascade Range, with LAVO and the surrounding region representing the southernmost extent of the species. This frog was once so abundant in LAVO that “one frog for nearly every meter” of lakeshore was reported during surveys conducted in 1925. Over the past several decades, the Cascades frog has experienced severe population declines in the southern extent of its range, particularly in LAVO. During comprehensive 2004 surveys of lentic waters in the park, only a few Cascades frogs were found and only in the vicinity of Juniper Lake. Resurveys in 2005 and 2006 revealed only one adult female frog remaining. All resurveys of this area since 2007 have been unsuccessful at finding frogs and currently no known Cascades frogs remain in LAVO.
Many factors, individually and likely in combination, have contributed to the species’ decline within the Lassen Region (Lassen National Forest (LNF), LAVO, and private timber lands). Nonnative fishes and pathogens (especially Batrachochytrium dendrobatidis [Bd]) have been found to have widespread impacts, and several other factors, particularly climate change, have been identified as potentially contributing factors affecting this species and its habitats.
Recent studies have found the fungal pathogen Bd, which causes the amphibian disease chytridiomycosis, to be widespread across the range in California and a principle cause for the dramatic decline of Cascades frogs in the southern Cascades Range. Bd arrived in the southern Cascades in the 1970s; just before Cascades frog declines were observed. Recent studies indicate that Bd is present in all remaining populations of Cascades frogs in the Lassen Region, but that some of these populations seem to be coexisting with the pathogen, with the availability of warm microhabitats at certain life stages being the critical factor to surviving with Bd.
Cascades frog populations near LAVO are coexisting with Bd, but populations continue to decline. This trend may be related to a change from snowmelt-dominated to a rain-dominated hydrology and an increased frequency of drought is compromising lower-elevation aquatic habitats. Remaining Cascades frog populations near LAVO occupy lower elevation meadows where the effects of the recent drought have been dramatic and caused recruitment failures due to habitat drying. LAVO, with most of the remaining intact, high elevation lake and wetland habitats in the region, can provide important climate refuges for Cascades frog and are now considered fishless. Historically, Cascades frogs were abundant in LAVO’s high elevation lakes. With climate change predictions, habitat within the LNF and surrounding area could become unsuitable, and LAVO may contain one of the few sites where this species can survive. The Cascade Frog conservation assessment recommends reintroduction into LAVO as a principle method for preserving the species within the region. However, before the park and its partners can begin this effort, surveys are needed to prioritize the lakes with the highest probability of success within LAVO. Ideal lakes are high elevation, open or with adjacent meadow areas, lack nonnative fish predators, and either have no BD or a strain that can be inoculated.
This project focuses on surveying suitable habitat within LAVO for future reintroduction, as the first step in re-establishing Cascades frog. Expected products include: 1) a final report, 2) site suitability recommendations, 3) next steps for implementing reintroduction, and 4) media for outreach and education. Media for outreach and education will be developed by NPS staff in conjunction with project experts. Media could include project briefs, social media postings, webpages, and project posters designed to meet NPS graphic identity standards and to fulfill LAVO’s directives for engaging public and stakeholders.
B. Objectives
Investigators from WSU and NPS staff will collaborate to accomplish the following specific objectives.
The long-term goal to successfully re-establish Cascades Frog within LAVO requires the completion of four phases: (1) Habitat/Site assessment; (2) Collect and rear animals from source populations; (3) Implement species restoration; and (4) Assessment of restoration success. This project focuses on completing phase 1, Habitat/Site assessment.
The specific objectives of this project include:
1. Evaluate the suitability of Cascades frog re-introduction sites in LAVO
2. Assess source populations in Lassen National Forest
3. Identify suitable habitat within LAVO for future reintroduction
C. Public Purpose
This project will benefit the public by providing new information to better understand habitat suitability for re-introduction and recovery of a rare amphibian. The general public will be provided with opportunities to actively participate by signing up with the Volunteer-In-Parks (VIP) program and assisting with capturing amphibians and habitat assessment. Geoscientists-in-the-Parks participants will also assist and learn capture techniques and habitat requirements as well as general biology of the Cascades frog. Project information and products will be publicly available through written resource briefs, the LAVO website and newspaper, and park ranger led programs. WSU students will gain from the real-world, research experiences in the project through field work and lab analysis of samples taken from LAVO amphibians.