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What is Biomonitoring?

Biological monitoring (or biomonitoring) is the use of a biological community to provide information on the quality or "health" of an ecosystem. Biomonitoring can be used to assess the water quality in streams, lakes, ponds, reservoirs, estuaries and oceans; macroinvertebrates, fish, and algae are all widely used in biomonitoring.

Biomonitoring in New York State

Since 1972, the Stream Biomonitoring Unit of the New York State Department of Environmental Conservation has used aquatic macroinvertebrates to monitor the water quality of the State's rivers and streams.

Although DEC collects information on different aquatic communities, biomonitoring surveys are primarily assessed by collecting benthic (bottom dwelling) macroinvertebrate samples from riffle habitats in streams and rivers. DEC's Stream Biomonitoring Unit also uses fish and algae communities for intensive surveys to assess the magnitude and type of environmental stress or impact in waterbodies.

Macroinvertebrate samples are collected from the appropriate habitat, preserved, then examined in the laboratory under a microscope to count and identify the different types of macroinvertebrates present in the sample. These data are used to assess the health of the stream or river using a variety of measurements. These measures are known as "biotic indices" or "metrics", which are features of the insect community that can be related to the health of the waterbody. Assessments also evaluate field-collected physical and chemical data, land use, and, if available, historical information.

Aquatic macroinvertebrate sampling methods and metrics are being developed for lakes and ponds. DEC has conducted a pilot study of 50 lakes throughout the state. Macroinvertebrates were collected from dominant habitat areas within the littoral zone (nearshore areas) at eight locations evenly distributed in the lake. Additional information about the habitat, temperature, dissolved oxygen, pH, and other water quality measures was collected at each sampling location.

Analysis of benthic communities is a reliable and cost-effective approach to water quality monitoring. Aquatic macroinvertebrates are often used because:

  • they are abundant,
  • they are relatively easy and inexpensive to sample,
  • they are sensitive to environmental impacts (stress, pollution, changes to habitat)
  • they have differing tolerances to pollution
  • they are less mobile than fish and cannot avoid discharges,
  • they are indicators of overall, integrated water quality, including synergistic effects and sensitivity to substances lower than detectable limits, and
  • changes in their community composition show the effects of non-chemical impacts to their habitat, such as siltation or changes in temperature

How are biomonitoring data collected?

DEC adheres to the procedures outlined in the Standard Operating Procedure: Biological Monitoring of Surface Waters in New York State, 2012 (PDF) (1.6 MB) to collect, process, and analyze biomonitoring data. This ensures uniformity of methods and accuracy of data when performing biological monitoring of surface waters in New York State. It documents the standard operating procedures (SOP) and quality control methods of the Stream Biomonitoring Unit of the New York State Department of Environmental Conservation. This document replaces all previous quality assurance work plans and/or SOPs issued by the Stream Biomonitoring Unit.

The SOP was prepared to meet Quality Assurance/Quality Control requirements for environmental monitoring audits, reviews of findings, and corrective procedures are conducted on a scheduled basis.

What are Aquatic Macroinvertebrates?

Aquatic macroinvertebrates are insects and other animals without a back bone (invertebrates) that can be seen with the naked-eye (without a microscope) that live in and on the bottoms of streams, lakes, ponds, reservoirs, estuaries and oceans. Freshwater macroinvertebrates include aquatic insects, worms, clams, snails, and crustaceans; view descriptions and see pictures of common freshwater macroinvertebrates that are found in riffle habitats in streams and rivers.

Some of these animals spend their whole lives in the water, but many mature into terrestrial insects that are seen flying around. They are important parts of freshwater environments because they:

  • provide food for other animals such as fish, amphibians, and birds
  • help to cycle nutrients
  • can be used by scientists to evaluate water quality

What do the bugs tell us?

The types and numbers of macroinvertebrates collected from polluted water differ from those collected in clean water. Macroinvertebrate community assessments help to determine "how clean" (level of water quality) the water is and to detect changes in water quality over time.

Different kinds of macroinvertebrates have varying tolerances (or sensitivities) to pollution and/or to changes in habitat and water chemistry conditions. The different features of a macroinvertebrate community (pollution sensitivity, abundance, diversity) or community metrics tell us about the quality or health of the waterbody. The DEC Standard Operating Procedure Biological Monitoring of Surface Waters in New York State contains detailed procedures for assessing water quality using the characteristics of macroinvertebrate communities.

Examples of Macroinvertebrate Community Metrics
Community Characteristic Description of Characteristic What it means
Biological Assessment Profile (BAP)* Integrates several community characteristic indices to calculate a single water quality score. Higher BAP scores indicate better water quality.
Biotic Index* A measure of the overall pollution tolerance of the macroinvertebrate community. The presence of pollution sensitive macroinvertebrates usually indicates better water quality conditions.
Ephemeroptera (mayflies), Plecoptera (stoneflies), Trichoptera (caddisflies)(EPT) Richness* The number of different kinds of mayfly, stonefly and caddisfly. Greater numbers of different kinds of mayflies, stoneflies and caddisflies is usually an indication of good water quality conditions.
Percent Model Affinity* A measure of similarity to a non-impacted community. The more similar a sample is to the non-impacted community indicates good water quality conditions.
Taxa Richness* Total number of different kinds of macroinvertebrates collected in a sample. Higher taxa richness usually indicates good water quality conditions.
Nutrient Biotic Index (NBI)* Measures nutrient enrichment of the stream based on the tolerance of different kinds of macroinvertebrates to nutrient pollution (phosphorus and nitrate). Lower NBI scores indicate lower nutrient enrichment.
Impact Source Determination (ISD)* Assess the types of impacts that may be affecting the stream or river based on the number and kinds of macroinvertebrates in a sample. Macroinvertebrate communities that resemble natural communities or are less than 50% similar to impacted communities indicate good water quality conditions.
Functional feeding group (FFG) Measures the proportion of each of the different types of macroinvertebrate functional feeding groups in a sample. FFGs are based on how food is collected by macroinvertebrates not what they eat: shredders, collectors, scrapers, predators, and piercers. There is an expected proportion of each FFG; it is related to the abundance of particular food resources. Depending on the habitat and FFGs present, may indicate a disturbed or undisturbed macroinvertebrate community.

How does DEC use this information?

Biomonitoring information is used to help determine current water quality and identify trends and possible future problems; assess water quality conditions before and after an activity or disturbance to a stream or river; assess regional reference sites, long-term monitoring locations, waters that have never been assessed and sites that are of interest to the public or DEC; to help track down water quality problems; or to collect baseline information. The information may also be used to determine whether or not a waterbody meets its designated use, Assessment Methodology, 2009 (PDF) (510 KB).

Information about the DEC programs that use biomonitoring data:

Watershed management and planning

Biomonitoring data are an important part of the development and implementation of watershed plans. Watershed plans involve stakeholders within the entire watershed, not just downstream of a problem and provides solutions for a number of pollution sources. Biomonitoring data help to determine baseline conditions and may be used to show improvement in water quality over time as the watershed plan is implemented.

Water quality standards

Biomonitoring data contribute to the basis for determining if waterbodies are meeting their best use classifications and if more or different protection or restoration efforts are needed. Standards for dissolved oxygen (DO), pH, dissolved solids, odor, color and turbidity were established to maintain biological integrity.

Nutrient criteria

Biomonitoring data and macroinvertebrate community indices are contributing to DEC's work to develop numeric criteria that better define the levels of nutrients that result in impairment of water uses. DEC has developed a NYS Nutrient Standards Plan (PDF, 127 KB) for the development of numeric criteria. The current plan focuses on phosphorus in fresh waters.

Publications by the Stream Biomonitoring Unit

Baldigo, B. P., Lawrence, G. B., Bode, R. W., Simonin, H. A., Roy, K. M., & Smith, A. J. (2009). Impacts of acidification on macroinvertebrate communities in streams of the western Adirondack Mountains, New York, USA. Ecological Indicators, 9(2), 226-239.

Bode, R. W., & Novak, M. A. (1995). Development and Application of Biological Impairment Criteria for Rivers and Streams in New York State. In W. S. Davis, & T. P. Simon (Eds.), Biological Assessment and Criteria Tools for Water Resource Planning and Decision Making (pp. 97-107). Boca Raton: CRC Press.

Bode, R. W., Novak, M. A., Abele, L. E., Heitzman, D. L., & Smith, A. J. (2004). 30 Year Trends in Water Quality of Rivers and Streams in New York State Based on Macroinvertebrate Data. (pp. 384).

Burian, S. K., Novak, M. A., Bode, R. W., & Abele, L. (1997). New record of Brachycercus maculatus Berner (Ephemeroptera: Caenidae) from New York and a key to larvae of northeastern species. Great Lakes Entomologist, 30(3), 85.

Burns, D. A., Riva-Murray, K., Bode, R. W., & Passy, S. (2008). Changes in stream chemistry and biology in response to reduced levels of acid deposition during 1987-2003 in the Neversink River Basin, Catskill Mountains. Ecological Indicators, 8(3), 191-203.

Bush, B., Simpson, K., Shane, L., & Koblintz, R. R. (1985). PCB congener analysis of water and caddisfly larvae (Insecta: Trichoptera) in the upper Hudson River by glass capillary chromatography. Bulletin of environmental contamination and toxicology, 34(1), 96-105.

Novak, M., Reilly, A., Bush, B., & Shane, L. (1990). In situ determination of PCB congener-specific first order absorption/desorption rate constants using Chironomus tentans larvae (Insecta: Diptera: Chironomidae). Water Research, 24(3), 321-327.

Novak, M., Reilly, A., & Jackling, S. (1988). Long-term monitoring of polychlorinated biphenyls in the Hudson River (New York) using caddisfly larvae and other macroinvertebrates. Archives of environmental contamination and toxicology, 17(6), 699-710.

Novak, M. A., & Bode, R. W. (1992). Percent model affinity: A new measure of macroinvertebrate community composition. Journal of the North American Benthological Society, 11(1), 80-85.

Passy, S. I., & Bode, R. W. (2004). Diatom Model Affinity (DMA), a New Index for Water Quality Assessment. Hydrobiologia, 524(1), 241-252.

Passy, S. I., Bode, R. W., Carlson, D. M., & Novak, M. A. (2004). Comparative Environmental Assessment in the Studies of Benthic Diatom, Macroinvertebrate, and Fish Communities. International Review of Hydrobiology, 89(2), 121-138.

Phillips, P. J., & Bode, R. W. (2004). Pesticides in surface water runoff in south‐eastern New York State, USA: seasonal and stormflow effects on concentrations. Pest Management Science, 60(6), 531-543.

Riva-Murray, K., Bode, R. W., Phillips, P. J., & Wall, G. L. (2002). Impact Source Determination with Biomonitoring Data in New York State: Concordance with Environmental Data. Northeastern Naturalist, 9(2), 127-162.

Simpson, K. (1975). Biology and immature stages of three species of Nearctic Ochthera (Diptera: Ephydridae). Proc. Entomol. Soc. Wash, 77, 129-155.

Simpson, K. (1976). The mature larvae and puparia of Ephydra (Halephydra) cinerea Jones and Ephydra (Hydropyrus) hians Say (Diptera: Ephydridae)[Insects]. Proceedings Entomological Society of Washington, 78.

Simpson, K. W. (1980). Abnormalities in the tracheal gills of aquatic insects collected from streams receiving chlorinated or crude oil wastes. Freshwater Biology, 10(6), 581-583.

Simpson, K. W. (1983). Communities of Chironomidae (Diptera) from an acid-stressed headwater stream in the Adirondack Mountains, New York. Memoirs of the American Entomological Society, 34, 315-327.

Simpson, K. W., & Abele, L. E. (1984). Ripistes parasita (Schmidt)(Oligochaeta: Naididae), a distinctive oligochaete new to North America. Freshwater Invertebrate Biology, 36-41.

Simpson, K. W., Fagnani, J. P., Bode, R. W., DeNicola, M., & Abele, L. E. (1986). Organism-substrate relationships in the main channel of the lower Hudson River. Journal of the North American Benthological Society, 41-57.

Simpson, K. W., Fagnani, J. P., DeNicola, D. M., & Bode, R. W. (1985). Widespread distribution of some estuarine crustaceans (Cyathura polita, Chiridotea almyra, Almyracuma proximoculi) in the limnetic zone of the lower Hudson River, New York. Estuaries and Coasts, 8(4), 373-380.

Smith, A. J., & Bode, R. W. (2004). Analysis of Variability in New York State Benthic Macroinvertebrate Samples. New York State Department of Environmental Conservation, Stream Biomonitoring Unit (pp. 43).

Smith, A. J., Bode, R. W., & Kleppel, G. S. (2007). A nutrient biotic index (NBI) for use with benthic macroinvertebrate communities. Ecological Indicators, 7(2), 371-386.

Smith, A. J., Thomas, R. L., Nolan, J. K., Velinsky, D. J., Klein, S., & Duffy, B. T. (2012). Regional nutrient thresholds in wadeable streams of New York State protective of aquatic life. in press.

Smith, A. J., & Tran, C. P. (2010). A weight-of-evidence approach to define nutrient criteria protective of aquatic life in large rivers. Journal of the North American Benthological Society, 29(3), 875-891.

Tran, C. P., Bode, R. W., Smith, A. J., & Kleppel, G. S. (2010). Land-use proximity as a basis for assessing stream water quality in New York State (USA). Ecological Indicators, 10(3), 727-733.