Northern Clearwater Crayfish call the Grand River ... - Lake Metroparks

Ask the Animals about
By Lake County Soil & Water Conservation District staff
If you want to know what is going on in a river, all you have to do is ‘ask’ the animals that live there. Lake County is
crossed by thousands of small streams (headwater streams) that join together to make up our river systems. These streams
contribute clean, cool water or warm, polluted water depending on what is going on in the watershed. We can tell which
watersheds have water quality problems by studying the insects, amphibians and fish that live in each stream. The Lake
County Soil and Water Conservation District has been assessing small, unnamed streams in an attempt to determine which
high-quality streams need most protection, and where pollution problems may exist. We have learned new things about
species, and established more accurate ideas of range and habitat requirements for some species. Here are some of the
animals (indicator species) that help illustrate the water quality picture:
Northern Clearwater Crayfish call the Grand River home.
They can thrive in calm, still waters or in places where the current
is faster and the bottom is rocky. However, the spread of nonnative
crayfish, including the larger and more aggressive Rusty
Crayfish, threaten the population of the native crayfish. Northern
Clearwater Crayfish are a special interest species in Ohio and
are native to the Great Lakes states and provinces. They can be
affected by a rise in the acidity of river water, metal pollution and
by loss of streamside forests.
Stoneflies require running water. They live among the rocky
areas of cool, shady streams. While some stoneflies eat dead
plant material, the one pictured here is a predator. Its main prey
is midges and blackflies, making stoneflies a good thing to have
around! Stonefly populations can be harmed by stormwater runoff
that has been warmed by the surfaces it flows across, and by
sediment that buries stonefly egg masses. They are one of three
main orders of aquatic insects used for measuring water quality
because they are very intolerant of pollution.
Two-lined salamanders are important residents of our
smaller streams. The larvae live in the water for two to three
years, eating insects like mosquito larvae and midges. Adults live
near streams in wooded areas and may become prey of birds,
snakes and mammals. Female two-lined salamanders tend to
their egg clutches until the larvae hatch. While these salamanders
are somewhat tolerant of changing stream conditions, loss
of streamside forests and increases in erosion due to poor
agricultural or construction practices can damage the streams
they rely on.
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Blacknose Daces require clear streams with gravelly bottoms.
They spend much of the year in clean pools, but require riffle
areas with fast-moving water for egg-laying. While the Blacknose
Dace is not nearly as picky as the closely-related Redside Dace, it
will not tolerate sediment pollution or lack of gravel in rivers.

Water Quality
Focus on Dragonflies
Dragonfly larvae are aquatic—they breathe
with gills and must stay in a wet environment.
Sixteen different dragonfly species live in Lake
County’s headwater streams and many others
inhabit rivers, ponds and lakes. Through study
of nymphs, we have learned that some species
not previously known to live in Lake County are
present here and reproducing in our rivers and
streams. The field sheets from the research
also give us clues about where to look for
additional populations of these species. By
combining the information on stream bottom,
forest canopy cover, temperature and other
measurements with the specimens collected
and identified in each stream, we create a more
complete picture of dragonfly distribution and
the habitat requirements of each species. That
information can then be used to determine
where else we would expect to see these
dragonflies. In the field, we can then look for
new populations of a particular species or
determine if they are absent due to a water
quality problem.
By sharing our findings with other agencies,
we have also helped to record new dragonfly
populations in Ashtabula, Cuyahoga and
Geauga counties. It has been determined that
some dragonfly species are not as tolerant
of water pollution as was once thought.
Dragonflies are typically categorized as
‘somewhat tolerant’ of pollution but we have
found that our stream species are ‘intolerant’
of degraded water quality. This could change
how streams are protected by landowners and
communities.
Eastern least clubtail dragonfly
Stylogomphus albistylus
Spiketail nymph
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