Hawkesbury-Nepean River Environmental Monitoring Program

Figure 6.10: Multidimensional scaling ordination of macroinvertebrate samples,
illustrating the difference between edge and riffle habitats for sites upstream and
downstream of dams and at reference sites
• pair-wise differences among sites were also often significant (ANOSIM P < 0.05;
Figures 6.11 and 6.12). In edge habitats, the Erskine Creek sites (N626 and
N6265) were not found to be significantly different from each other. Similar results
occurred for riffle habitats, although in these habitats other sites were also found
to be similar (e.g. sites N886, N932 and N97) 15 .
• there are few water quality data available for some sites upstream or downstream
of dams or at reference sites; depending largely on whether or not the
macroinvertebrate sampling site coincided with a routine water quality monitoring
site. This means that there was limited scope for investigating the relationship
between macroinvertebrate communities and water quality at these sites.
• in the above comparisons, differences over time are potentially confounded with
sampling organisation, flow changes and periods of drought.
15 Because of a lack of riffle samples at N93, pair-wise comparisons among sites involving
N93 were often unable to reach the 0.05 probability level owing to low numbers of
possible permutations.
Hawkesbury Nepean River Environmental Monitoring Program: Final Technical Report 35