Mountain Lake Monitoring
Research Summary
The first step scientists took to determine the health of North
Cascades high country lakes was to separate them into four categories.
Lakes were categorized according to these features:
- elevation
- total area
- depth
- whether the lake had a surface outlet flowing downslope
- whether it was surrounded by trees or talus (rocks)
Scientists then counted many of the benthic macroinvertebrates
(insect larvae, snails, clams, etc.) that lived in 'healthy' reference
lakes in each of the four lake categories. They now believe they
have a baseline list of which taxa (species of plants and animals)
should be living in each of the four lake types.
The lake features listed above and the data on the macroinvertebrates
were used to create a predictive model. The predictive model allows
researchers to collect data on an untested lake, plug the data into
the model and receive a prediction about which taxa of macroinvertebrates
are expected to be found there.
To use the predictive model to check the health of a lake, scientists
take the following three steps:
- Measure a lake's features and find out what category it belongs
to.
- Survey the lake for macroinvertebrates.
- Compare macroinvertebrates found in the lake with the taxa they
expect to be there.
If few of the expected taxa are found to live in the lake, the
lake is considered "below reference," and possibly unhealthy.
While some lakes do not contain expected taxa, others are dubbed
"richer than reference." These lakes have more of the
healthy insect life than the researchers expected to find. Such
lakes could be considered in very good condition.
Use the three steps above and test your ability to Monitor
a Mountain Lake.
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