National Park Service

Eastern Rivers and Mountains Network (ERMN)

Wadeable Stream Monitoring

A mayfly (Epeorus sp.) commonly found in ERMN wadeable streams
A mayfly (Epeorus sp.) commonly found in ERMN wadeable streams

Protocol Documents

Summary Reports

Vital Signs

Benthic Macroinvertebrates, Water Quality


There are approximately 211 miles of rivers and more than 425 miles of streams throughout the ERMN. The importance of water resources is reflected by the network’s ranking of benthic macroinvertebrates (BMI), river and stream hydrology, and water quality as 3 of the top 4 vital signs.

Benthic macroinvertebrates are aquatic invertebrates that are larger than microscopic size and live on or within the stream bottom (benthos). In addition to being instrumental to nutrient and carbon dynamics in streams, BMI are an important link between basal resources (e.g., algae and detritus) and higher trophic levels (e.g., fish and birds) in stream food webs. Because BMI are a vital component of all functioning stream ecosystems, they are the most commonly used assemblage for biological monitoring of aquatic ecosystems. Furthermore, many BMI metrics have been evaluated with respect to natural variation and responses to various sources of human-induced degradation. Given the proven ability to derive ecosystem integrity based on measures of BMI assemblage structure and composition, combined with the relatively low cost to sample, BMI are widely regarded as the single best biological group to assess and monitor the ecological integrity of wadeable streams.

Physical and chemical characteristics of water have strong effects on aquatic biota; consequently, direct and indirect human alteration of stream water quality is associated with altered biotic communities and ecosystem processes. Because of the direct relationship between water chemistry and biota, the ERMN monitors core water quality parameters” (temperature, conductivity, pH, and dissolved oxygen) that are critical to understanding baseline conditions in aquatic habitats. 

Monitoring Effort

all ERMN parks except Upper Delaware SRR

Monitoring Objectives

  • Determine the status and trends of BMI assemblages in ERMN wadeable streams by way of diversity, abundance, and community metrics,
  • Determine the status and trends of habitat condition (both instream and streamside) and water quality by way of reach-wide rapid habitat assessments and point-in-time measurement of core water quality parameters (i.e., dissolved oxygen, temperature, pH, conductivity),
  • Relate condition of BMI communities in ERMN streams to water quality and habitat condition with regionally developed multi-metric indices, and
  • Assess effects of key stressors on BMI.

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Last Updated: December 30, 2016 Contact Webmaster