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Location: Habitat, Fisheries Project Summary
While current opinion holds that marine survival is the most important variable determining the abundance of most wild salmon, there is evidence that the decline of coho in the Thomson watershed for example, can be attributed at least in part to freshwater habitat alteration. There has been the suggestion that in some species, up to half of the variability might come from the freshwater life phase. Also, there is reason to expect reduced peak and summer river-flows and changes in timing of peak flows and increased stream temperatures as the climate changes - all parameters that can be expected to be related to variations in seasonal vegetation cover measurable from satellites. Borstad Associates Ltd. will produce a series of high-level ecosystem indicators of the biophysical condition of watersheds important to wild salmon, using a satellite-derived measurements of green vegetation. We will use satellite data to map and monitor changes in major salmon watersheds of the Fraser Basin during the 22-year period from 1985 to 2006. The satellite dataset is a massive 5 Terrabyte database of daily, 1km resolution weather satellite data composited to 10-day periods to reduce the data volume and the effect of clouds, but retaining the 1km resolution. A more or less continuous record of more than 500 vegetation cover measurements are therefore available for every imaged 1km pixel in the 22-year period. Each time series can be expected to provide parameters such as the rate and timing of green-up in the spring, the annual maximum plant cover, and losses due to droughts, fires, insects and logging, all of which are related to water quality and stream flow important to salmon. In cooperation with Dr. Jim Irvine (DFO) and Scott Akenhead of S4S Advisors Inc. we will examine the linkages between the satellite derived indicators with metrics of salmon production and survival in freshwater in selected watersheds of the Fraser Basin.
The deliverables will include:
The historical dataset to be assembled will provide high-level indicators of watershed health that could eventually be used in regular monitoring across very large areas. If successful indicators can be found, they could provide for inexpensive monitoring and assessment of habitat status of freshwater systems.
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