ATV damage on E. Amity Creek
Filamentous algae
Filamentous algae


Filamentous algae in
ATV damaged section


Riffle embeddedness 0 – 35%
Lots of crayfish
Hydropsychid & Glossosomatid caddisflies in areas with less filamentous algae

Filamentous algae

Close-up images taken along a section of the east branch of Amity Creek where ATVs run up and down the streambed itself. In this area we observed large amounts of nuisance filamentous algae. This excessive algal growth indicates extra nutrients in the stream; it is likely that ATVs are helping release extra nutrients from the stream and bank sediments as the drive over the area and churn up the stream bed, gravel bars, and damage stream banks. When this filamentous algae decays, it can lower dissolved oxygen concentrations in the water, which can be hard on fish and aquatic insects.

The stream in this area is more embedded with sand and silt – in other words, the rocks and gravel are starting to get buried by excess sediment stirred up by ATV use of the creek and by erosion from damaged stream banks. This burial means less habitat for stream insects (“fish food”), and less spawning habitat for trout and other gravel-spawning fish.

We also observed many crayfish in this section of the stream. Crayfish are a hardy stream dweller that can withstand conditions that more sensitive insects and invertebrates could not tolerate. The caddisflies we found in this area were also indicative of poorer water and habitat quality and seemed to be responding to the abundant algae.

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