The different versions of the MCI can be used at all levels, ranging from very specific technical impact assessments or consent compliance assessments, through to high-level SoE reporting at the catchment, regional or national scale. In addition, these indices have found widespread use in the formal scientific literature as a way to assess impacts of various kinds on stream communities, and many of these studies have served to confirm the ability of these indices to assess environmental health in robust and useful ways.
When preparing any report it is essential to consider the target audience, and use tools and language that convey information appropriately. There is no point preparing a highly technical report that only experienced macroinvertebrate ecologists will understand when the target audience comprises regional councillors or the general public. As mentioned earlier, commonly used indices such as taxa richness, MCI and SQMCI do not measure exactly the same thing, so assessments based on them are not necessarily in complete agreement and reporting them all together may present a confusing picture.
We recommend plotting maps similar to Figure 3 to present an overview of macroinvertebrate SoE monitoring on a regional or national basis. In this example, blue dots indicate where MCI values suggest that stream health exceeds expectations, green dots indicate that expectations are met, and red dots indicate sites where some improvement is desirable. We prefer the traffic light analogy, with green indicating stream health that meets expectations, orange indicating that there is some room for improvement, and red indicating that there are real problems that need to be addressed. Classification of index scores (Table 2) provides a consistent basis for colour-coding index scores. These quality classes, coupled with mapping, are an effective way to communicate results to non-scientists.
Source: Taranaki Regional Council 2003