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Freshwater Macroinvertebrate Atlas

About the data in the maps

The data used to create the distribution maps is based on kick net samples collected by DEC in riffle habitats from 1984-2009. New York Natural Heritage Program produced the maps for DEC.

What the maps show

The locations where the aquatic insects have been collected by DEC in NY:

  • The relative abundance of the taxon in the sample
  • The water quality score of the stream calculated from the identification and count of all the taxa collected from the kick sample.

Find information about sample methods and metrics go to the Biomonitoring web page.

Limitations of the maps

The maps do not represent all possible locations where the aquatic insects may be found in NY, but are the locations where the taxa were collected by DEC from 1984-2009 in riffle habitats. Maps may be updated in the future as resources permit.

Maps do not include all taxa that may be found in New York. Maps for three major groups of aquatic insects are available: Ephemeroptera (mayflies), Plecoptera (stoneflies), and Trichoptera (caddisflies) . Changes or updates to the group names (taxonomic nomenclature) may not be reflected in these maps.

Why mayfly, stonefly, and caddisfly distribution maps?

Most kinds of mayflies, stoneflies, and caddisflies are sensitive to pollution and their presence is usually an indication of good water quality. Mayfly, stonefly and caddisfly larvae are part of the widely used EPT Index (Ephemeroptera-Plecoptera-Trichoptera) to measure environmental condition. The index is the number of different mayflies, stoneflies, and caddisflies taxa. The more different kinds of mayflies, stoneflies, and caddisflies may indicate good water quality.

For distribution maps of Odonata (dragonflies and damselflies) see the New York State Dragonfly and Damselfly Survey page.

More about Freshwater Macroinvertebrate Atlas: