Look at our streams with new eyes 

click to enlarge Crabapple creek
  • Crabapple creek

By Carol Coffey

for the Whistler Naturalists

Whistler has beautiful lakes and creeks that we enjoy everyday; pretty vistas, the soothing sounds of the water, located right in our backyard. We are fortunate to live in this environment that supports our health but let’s ask ourselves how healthy is the local environment for the creatures with which we share our spaces.

Our local watershed is home to a diverse array of plants and animals. The streams are a good indicator of the health of our watersheds. Residential, commercial, industrial and recreational development has brought pressure on our streams. It is interesting to take a closer look at your local stream to see what habitat it provides for fish and wildlife.

Natural streams form meandering pool-riffle sequences that are important for fish. Pools are deeper areas with slower moving water and soft sediment at the bottom. Pools provide places for fish to rest and hide. Riffles are shallow areas of a stream where fast-moving water bubbles over rocks and gravel. Riffles help to oxygenate the water and provide spawning habitat. Local fish species such as rainbow trout, kokanee salmon and bull trout require cool water flowing over clean gravel for spawning. Where humans have straightened streams, the diverse habitat features that fish and other aquatic species require are often lost.

Look at your local stream to see what kind of cover is available for fish. Fish love logs, boulders, and aquatic plants because they provide shelter and good places to find food such as aquatic insects.

Streams are always changing; vegetation grows and dies, trees and branches fall into the water, sediment moves, spawning beds shift, new channels form, and banks erode. These are natural processes that create habitat diversity in a stream such as pools, woody debris and undercut banks.

Too much erosion can become a problem though because it introduces sediment into the stream. Fine sediments fill in the spaces between pieces of gravel and reduce the quality of the habitat for fish eggs. Invertebrates (insect larvae, worms, snails etc.) also live in these intergravel spaces and increased amounts of sediments reduce the amount of habitat available to them. Less invertebrates means that there is less food for the fish and so affects the entire food chain.

The riparian area is the zone on either side of the stream. Stream bank vegetation is essential to the health of the stream. It binds the soil to prevent erosion, shades the water to keep it cool for fish and aquatic organisms, helps absorb runoff, and provides a source of nutrients and food. Riparian areas play an important role in reducing the velocity of floodwater and surface runoff.

Riparian areas also provide habitat for birds, and amphibians. Frogs and toads are sensitive to changes in the environment and are also a good indicator of the health of an ecosystem. Grass, leaf litter, small twigs, logs, and rocks provide places for amphibians to live.

If you would like to get to know a section of your local stream you can become a Stream Habitat Steward for the Whistler Fisheries Stewardship Group. Simply visit a section of your local stream three times a year (in spring, summer, and fall) and make observations on the stream using an easy checklist. Volunteers will be provided with a manual and checklists to take with on their walks.

For more information contact the Whistler Fisheries Stewardship Group at 604-935-8323 or e-mail ccoffey@whistler.ca


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