concentrations) and physical nature of receiving streams, which in turn
affects the stream ecosystem. Benthic macroinvertebrates are used to illustrate
these impacts, and to investigate natural recovery in affected streams. In
Charming Creek, a severely impacted stream in the Buller District, the
macroinvertebrate community recovers diversity and the proportion of sensitive
species (EPT) in the community is more significant with increasing downstream
distance from the source of AMD. This is most likely due to dilution of AMD
contaminated water by tributaries to the Charming Creek mainstream. Other
impacted systems with less dilution from tributaries did not display similar
levels of recovery. The effectiveness of remediation products Bauxsol and
Zeolite was investigated using laboratory trials. Both products mitigated the
toxicity of AMD and enhanced the survival of mayflies exposed to AMD
contaminated water. Such products may be of use in the New Zealand environment
but are likely to be most effective in conjunction with other systems (eg
wetlands). Mitigating the impacts of AMD on stream ecosystems needs to include
systems to directly address water chemistry issues (low pH, high metal
concentrations) as a component of a holistic approach to restoring environmental
conditions.