50 the riparian zone is dense with black tree fern (Cyathea medullaris) the dominant species, with some remnant mature pine trees present. Further detail of the habitat characteristics of the Ruahorehore Stream sample sites is provided in Appendix 4. 10.2.1.3 Benthic Macroinvertebrates Characteristics The macroinvertebrate assemblages within the Ruahorehore Stream varied along its length with varied taxa number and macroinvertebrate abundance. Macroinvertebrate communities were generally similar, but the uppermost forested site was notable for a greater dominance of EPT taxa, with the stonefly Acroperla (33 individuals) and the mayflies Arachnocolus (27 individuals) and Coloburiscus (26 individuals). The presence of the two mayflies in such abundance is an indicator of high habitat and water quality. In contrast, the lower reaches were dominated by other species such as Oxyethira and the snail Potamopyrgus antipodarum. MCI-sb scores in the Ruahorehore Stream varied between 74 (RUA_lower) and 115 (RUA_forest). Water and habitat quality as assessed using macroinvertebrate indices thus varied between good in the upper reaches to poor in the lower reaches10. As detailed above, Appendix 2B of the NOF provides for the preparation of attributes requiring action plans and include attribute bands for the MCI and QMCI. We acknowledge that our results represent a single survey, but the results show that the upper Ruahorehore Stream falls within Attribute band B, while the lower Ruahorehore Stream is below the national bottom line in band D for the (Table 18). Further detail on the macroinvertebrate communities of the Ruahorehore Stream is provided in Appendix 5. Table 18:. Summary of macroinvertebrate metrics from the Ruahorehore Stream catchment along with comparison with NOF. Site RUA_Lower RUA_Upper RUA_Forest RUA_Trig Road RUA_Revegetated Taxonomic richness No. of EPT taxa 4 8 7 7 10 Percent EPT MCI 74.1 110 115 80 83 SQMCI SEV 0.435 0.532 0.85 0.403 0.575 MCI NOF Action Plan Attribute Band# Band D (Below NBL^) Band B Band B Band D (Below NBL^) Band D (Below NBL^) SQMCI NOF Action Plan Attribute Band# #Attributes requiring action plans are provided for by the NOF (NPSFM, Chapter 2B). ^NBL = National Bottom Line. 10 Interpretation of the classification of MCI and QMCI scores is provided in Table 3-3 of Appendix 3 of this report.
RkJQdWJsaXNoZXIy MjE2NDg3