Stream Plethodontid Assemblage Response (SPAR) Index: Development, Application, and Verification in the MAHA

EPA Grant Number: R827640
Title: Stream Plethodontid Assemblage Response (SPAR) Index: Development, Application, and Verification in the MAHA
Investigators: Brooks, Robert P. , Rocco, Brian L.
Current Investigators: Brooks, Robert P. , Rocco, Brian L. , Hite, Jeremy T.
Institution: Pennsylvania State University
EPA Project Officer: Packard, Benjamin H
Project Period: July 1, 1999 through June 30, 2002
Project Amount: $397,304
RFA: Ecological Indicators (1999) RFA Text |  Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , Aquatic Ecosystems


Forested headwater streams comprise 60 75% of the total stream length and watershed area in the Mid-Atlantic states and are impacted by a variety of environmental stressors. Amphibians, in general, are considered to be valuable response indicators. In the Appalachian Region, a diverse assemblage of Plethodontid (lungless) salamanders thrive and reproduce in seeps, brooks, and small streams and can exist in extremely high densities. Unlike vemal pool breeding species, populations of most stream dwelling salamanders tend to be remarkably stable over time. Life histories within this group are highly variable and consist of aquatic and terrestrial egg-laying species with variable aquatic larval periods (8 months - 4.5 years). Previous studies indicate that early amphibian life stages (eggs, embryos, and recent hatchlings) are the most sensitive to low pH and metal toxicity. Interspecific differences in tolerance also exist within similar lifestages. If stream plethodontids show similar ontogenetic changes and interspecific differences, acidified or otherwise adverse stream conditions are likely to be important elements in shaping streambank salamander assemblages either through direct toxicity or indirect ecological interactions among community members. By virtue of their diverse and complex life histories, and abundant, stable, and geographically widespread populations, stream plethodontids offer the opportunity of providing another biological tool to assess headwater impairment and degradation, especially where traditional species assemblages (macroinvertebrates, fishes) are poorly developed or absent. A pilot project conducted in 1997-98 in 14 headwaters in the Allegheny Plateau, Pennsylvania, (Rocco and Brooks in prep) shows that stream salamander assemblages do respond to stream impairment. A dramatic response was documented in three species.

The objectives of this research are: 1) To describe the range and variability of stream plethodontid assemblage responses (SPAR) across commonly encountered gradients of anthropogenic degradation (stream acidification, forest and riparian corridor fragmentation and degradation, pollution, etc.) in the Mid-Atlantic Highlands Area (MAHA). 2) To develop and adjust SPAR for use in MA~ headwaters. 3) To evaluate the reliability and resolution of SPAR by application and verification.


The development, application, and verification of SPAR within MAHA will entail a two phase process. Phase I aims to document and study plethodontid assemblage responses to as many different stream conditions as possible, across a large geographical area. This dataset will enable the development of the SPAR index for the MAHA. In Phase II, a random set of headwaters of unknown condition will be sampled and its impairment determined by the SPAR index. Once applied, an independent assessment of the stream by other methods (macroinvertebrates, water quality, surrounding landscape) will allow the verification of the reliability and consistency of the index, and if necessary, its calibration. The use of volunteers, also in the second phase, will permit evaluation of the method for non-specialists and long-term amphibian monitoring efforts. The response composition of free-ranging, naturally occurring stream salamander populations in degraded (episodic acidification, acid mine drainage, and urbanization) and non-degraded watersheds will be studied by intensive sampling. Relevant abiotic and biotic variables at the plot, stream reach, and watershed will be measured.

Expected Results:

Description of stream salamander assemblage response along disturbance and pollution gradients commonly encountered in the MAHA Region. Identification of species most responsive to the environmental degradation investigated. Provide recommendations on the use of stream salamander assemblages in the assessment of headwaters. Development and testing of stream salamander metrics (e.g. lifestage proportion, common species proportions) that could be implemented separately or in conjunction with other criteria when performing small stream assessments. Ultimately, this work would lead to the improvement of existing headwater assessment protocols by the addition of a bioindicator that is abundant, widespread, ecologically important to several trophic levels, and interfaces between aquatic and terrestrial components of riparian areas.

Publications and Presentations:

Publications have been submitted on this project: View all 7 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 1 journal articles for this project

Supplemental Keywords:

stream salamander, stream, environmental assessment, sentinel species., RFA, Scientific Discipline, Ecosystem Protection/Environmental Exposure & Risk, Hydrology, Ecology, Environmental Chemistry, Ecosystem/Assessment/Indicators, Microbiology, Ecological Effects - Environmental Exposure & Risk, Ecological Risk Assessment, Ecological Indicators, ecological exposure, forested headwater ecosystems, aquatic biota , watersheds, amphibians, MAHA, stream ecosystems, salamander population, ecosystem indicators, aquatic ecosystems

Progress and Final Reports:

  • 2000 Progress Report
  • 2001 Progress Report
  • Final Report