Water Stewardship Information Sources
| ID | 989 |
|---|---|
| Citation | Jensen, EV. 2007. The Biological Integrity of Okanagan Streams: Using Benthic Invertebrates to Monitor Stream Health. BC Ministry of Environment. |
| Organization | Ministry of Environment |
| URL | http://www.env.gov.bc.ca/epd/regions/okanagan/waterqual/pdf/benthic_invert_2007.pdf |
| Abstract/Description or Keywords | The Okanagan's ecosystems are coming under increasing pressure with the population growth and associated development currently experienced in the region. We sought a method of assessing the health of the Okanagan's lowland streams, many of which are in or near urban areas. We chose to use benthic invertebrates as indicators of stream health. In streams, benthic invertebrates are often the larvae of aquatic insects. Because they typically spend most of their life cycle in the stream, these invertebrates respond to conditions in and near the stream and integrate these effects over time. After examining the benthic invertebrate community in several Okanagan streams, we selected five measures, or metrics, that describe the community: ﾕ Total number of taxa ﾕ Number of stonefly taxa ﾕ Number of mayfly taxa ﾕ Number of intolerant taxa ﾕ Number of clinger taxa These metrics were selected for their predictable and measurable response along a gradient of land use. The metrics were combined into a benthic index of biological integrity (B-IBI) following a method widely used in the Pacific Northwest. We developed a version of the B-IBI specifically to assess Okanagan streams at low elevations in the valley bottom, and we then ranked the health of 31 stream sites using the index. The Okanagan B-IBI scored 21 of the 31 stream sites (68%) as having fair, poor, or very poor condition. Only 5 scored as good and 5 as excellent. The lowest scores were recorded for urban streams such as BX Creek in Vernon, Mill Creek in Kelowna, and Eneas Creek in Summerland. This information is useful for reporting the present ecological integrity of Okanagan streams and for tracking changes over time. In this report, we describe the reasons for using a biological index, how the B-IBI was developed, how the B-IBI compares with other monitoring methods, and the current B-IBI results for Okanagan streams. |
| Information Type | report |
| Regional Watershed | Okanagan |
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| Project status | complete |
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