EFFECT OF HABITAT TYPES ON THE BIOLOGICAL MONITORING OF ACID-MINE DRAINAGE IN RIVERS

The difference in productivity and diversity between habitats at indiv idual sites were examined to establish the most effective sampling met hodology to assess the impact of acid mine drainage (AMD). Collection of five replicate pond-net kick samples (20 seconds duration) is consi dered adequate for monitoring the impact of AMD. The use of taxa numbe rs in riffle areas was found to have the greatest discriminatory power . Forty-two taxa were identified. The percentage representation of Chi ronomidae showed an increase in response to AMD rising to almost 100% in the mixing zone and then decreased. In general, there was no taxa u nique to sites impacted by AMD. The response of the faunal community t o AMD is a significant drop in the number of taxa accompanied by a sha rp drop in the abundance of tart remaining.