Proceedings - Teaching and Learning Centre - Simon Fraser ...

Fraser River Action Plan 3rd Research Workshop
Development of a Biomonitoring Programme
for the Fraser River Catchment Basin using Reference Condition
T.B. Reynoldson 1 , K.E. Day 1 and D.M. Rosenberg 2
1 National Water Research Institute
2 Freshwater Institute
Presentation Slides by S. Kirby
The assessment of the ecological risk (ERA) of various impacts to watersheds from anthropogenic activities
often involves the comparison of biological communities at sites with suspected disturbance to sites in so-called
pristine reference areas. In riverine environments, this usually includes a comparison of communities located
upstream from point-source pollutants to communities located downstream from the source(s) of disturbance.
Many of these comparisons use methods which are traditional to freshwater biological studies (i.e., biotic indices
and univariate statistics with relatively few control sites) which may be located either within the same body of
water or, more rarely, in differing bodies of water.
There are a number of problems with these traditional approaches which have received discussion in recent
years, including:
• difficulties in finding unimpacted sites and in matching habitats of ‘clean’ sites with contaminated sites;
• problems in the interpretation of the inherent natural variability in species composition;
• abundances at sites with differing environmental characteristics; and,
• interpretation of the ‘ecological relevance’ of the results.
The definition of a ‘reference site’ has changed in the past few years (Davis and Simon, 1995) and it is now
accepted that there are no ‘pristine’ sites in most areas near anthropogenic activities. However, candidate
reference sites should represent ‘least disturbed’ conditions, as well as cover the range of ‘best attainable
conditions’ given the current use patterns for any stressors in any given region.
In recent years, there have been a number of studies which have expanded the concept of a few reference sites to
‘sets of reference sites’ located either regionally or grouped by similarities in characteristics such as the structure
of the floral and faunal communities or by chemical and physiographic variables. This grouping of reference
sites has been termed the ‘reference condition’ (Wright et al., 1988; Johnson and Wiederholm, 1989; Corkum,
1989; Norris and George, 1993; Reynoldson et al., 1995; Hughes, 1995; Rosenberg et al., 1995). The reference
condition approach tried to find common patterns in the structure of biological communities at ‘least impacted
sites’ using multivariate classification techniques and then determine the environmental variables which
constitute these community structures. The result of the multivariate analysis is the formation of a number of
groups of community types which form the ‘reference’ condition. The environmental variables which drive these
groupings are then used in a predictive model to determine the structure of the biological community at test or
impacted sites (i.e., the model predicts what communities should be present at a site if the site was undisturbed).
The actual community at a test site can then be compared to the reference community group for similarities in
structure. This provides a method to separate ecological variability from true stress-related changes.
We are currently using this multivariate statistical approach at a large number of ‘reference’ sites in the Fraser
River watershed and are in the process of developing a predictive model for erosional zones in first to ninth order
streams. This approach involves an extensive sampling regime over a three-year period for such ‘least impacted’
sites and has the following objectives:
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