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Ecosystems are communities of plants and animals that interact with one
another as well as with the physical environment.** They provide a wide
range of services to humans, including lessening weather extremes,
purifying the air and water, and renewing soil fertility.** Streams are
very important for riparian habitats. They provide habitat for
freshwater organisms and food and drink for terrestrial organisms. They
are helpful in moderating the climate and maintaining general
biodiversity.
Humans can have both direct and
indirect effects on stream health. Removing elements such as rocks and
fallen trees from streams can remove important habitat and hiding
places, as well as change the current flow. If we remove water from the
stream, it is likely to have low dissolved oxygen levels and could even
dry up in the summer. We also are known to add elements to the streams,
such as toxins, sediment, and chemicals, that destroy the quality of the
water and the health of the organisms.
A
useful way to study the health of local streams in your area is to use
macroinvertebrates (i.e. little insects living in the streams) as
bioindicators. Some of these insects can only live in high-quality
streams. Therefore, their presence would indicate a healthy environment.
Likewise, some insects can live anywhere, so their presence may indicate
a less-healthy stream.
Biology 112 (Diversity of Life) assessed the quality of three local
streams: Hylebos Creek, Swan Creek, and Mason Creek.
-Hylebos
Creek in northern Pierce County is an urban stream that has recently
gotten restoration attention by the Friends of Hylebos Creek in an
attempt to improve the salmon run.
-Swan
Creek in east Tacoma is the largest stream being assessed. It is under
restoration by NOAA's Damage, Assessment, Remediation and Restoration
Program (DARRP). Click
here for
information on this project.
-Mason Creek is under restoration by the Puget Creek Restoration Society
and feeds into the Puyallup River. It is located right next to a North
End Sewage Treatment Plant.
*Modified from
Biol112 lab "Assessing Environmental Health Using
Macroinvertebrates: Sampling aquatic insects in local streams" by
Dr. Jennifer Burnaford
**ESA. 2000. "Ecosystem
Services: A Primer." from
www.actionbioscience.org.
Hylebos Creek
Swan Creek
Mason Creek
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