Insects as Indicators
Insects as Indicators

Insects as Indicators

As we see the seasons changing from the long hot days of summer to the cool crisp mornings of fall the Lake Windermere Ambassadors are also shifting our gears as we enter the final Deep Dive of 2021, Our Shared Home. Over the next few months, we will be taking a closer look at all critters whom we share Lake Windermere with. This month, the spotlight is on insects, benthic macroinvertebrates to be precise.

If you break down the name, benthic macroinvertebrates, you get the definition of just exactly who these creatures are – bottom-dwelling, small – but visible with the human eye, animals and larvae that lack a backbone. Many of the benthic macroinvertebrates we see in the water around here are the larvae stage of common insects we see throughout the summer, such as the dragonflies and mosquitos. While you are likely more familiar with their flying form, these insects usually spend most of their life under water, like many years submerged and just a few hours to days above water as a fly.

So, what the big fuss over these little organisms? Well, since they spend most (if not all) of their time in the water they do a pretty good job at telling us about the quality of the water. In addition to the time spent in water they are also good indicators because they don’t travel far, are easy to collect, and respond in predictable ways to human influence. We use information about the abundance and variety of invertebrates to determine water quality.

In general, a healthy aquatic system will support a large variety of invertebrates in high populations. If we see samples that have only pollutant-tolerant species (ie. midge larvae or aquatic worms) that becomes a pretty clear indicator that there is a cause for concern about the quality of the water. In addition to alerting us of sudden changes, their inability to travel has made them good indicators of long-term changes. This, based on the fact that they need to adapt when a short-term threat becomes a long-term change of habitat.

Since September of 2013 the Lake Windermere Ambassadors have been collecting information about the macroinvertebrates in Windermere Creek through the Canadian Aquatic Biomonitoring Network. In 2019 we added the collection of environmental DNA to this monitoring thanks to support from the STREAM project. This added value to our monitoring as it provides a more complete profile of the biodiversity content from a small sample.

The Lake Windermere Ambassadors would like to thank the Columbia Basin Trust, Columbia Valley Community Foundation, Columbia Valley Local Conservation Fund, Real Estate Foundation, BC Gaming Grants, District of Invermere, Regional District of East Kootenay, BC Hydro, and community donors for supporting our 2021 programming.

Shannon McGinty, Program Coordinator for the Lake Windermere Ambassadors. Email her at shannon@lakeambassadors.ca or call the office (250) 341-6898.

 

Lifecycle of Stonefly (Left) and Mosquito (Right) demonstrating difference between larvae and adult stage.

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