Aquatic Invertebrates

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Outline for a report

Aquatic Invertebrates
Used to Classify Stream Health

Ecosystem
All things contained in an environment
Water (input and output)
Climate
Daylight
Plant life
Clear Cutting
Clear Cutting seriously effects all aspects of an ecosystem
Maine is, per capita, the most heavily logged state in the continental U.S.
Why Clear Cutting is Used
Simple
Creates a uniform forest to harvest in 40 years or so
Easy to replant
Cheap to Maintain (pesticides)
Clear Cutting Impacts on Streams
Clear Cutting seriously effects stream ecosystems
The effects of clear cutting can be felt on stream ecosystems for up to 60 years
The First Five Years After a Clear Cut
This time period is actually beneficial in most aspects of stream animal (vertebrate and invertebrate) health
The increase in CWD creates resources for life
Nutrients good for aquatic species increase
Nitrogen levels increase 40 times
Potassium levels increase 11 times
After Five Years
The negative effects of clear cutting begin to be felt
Increase in fast growing vegetation catches nutrients
Increased solar radiation leads to increased water temperatures
With no protection, water temperatures drop drastically at night
After Five Years (continued)
Packed soil and new vegetation lead to increased water input
Leading to higher peak flows and washing out CWD and boulders (habitats)
The stream widens and becomes shallower
Overall homogenization of the stream occurs
Second Growth
After 30-40 years, second growth forests develop
The stream ecosystem stabilizes
Stream Invertebrates
Stream invertebrates have adapted to the harsh stream environment
Mayflies are flattened from top to bottom, allowing them to swim fast in low current areas
Blackflies produce a substance to attach themselves to rocks when the current is strong
Many aquatic insects have tarsal claws used to attach themselves to rocks to avoid the current
Identifying Stream Quality with Stream Invertebrates
These adaptations have led to species that easily survive in polluted streams and those that don’t
Streams can be classified by the types of insects in them
There are 3 different categories of aquatic invertebrates when referring to stream health
Invertebrate Body Parts
Healthy Stream Invertebrates
Invertebrates that live in a healthy stream are classified as Group One Taxa
Healthy streams contain high biodiversity
Some examples are...
Stonefly
1/2 to 1.5 inches long
2 tails
6 legs with hooked tips
Caddisfly
Up to 1 inch
“Shell” made of mud sticks or small rocks
6 hooked legs
Different Caddisfly “Shells”
Riffle Beetle
1/4 inch long
6 legs
Oval body covered with tiny hairs
Mayfly
1/4 to 1 inch long
2 or 3 tails
6 large hooked legs
Often confused with the Stonefly
Moderately Healthy Stream Invertebrate
Invertebrates that live in moderately healthy streams are classified as Group Two Taxa
Moderately healthy streams support a lower number and diversity of species
Some examples are...
Crayfish
Up to 6 inches long
8 legs, 2 claws
Dragonfly

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