The concept of “sustainable ecological succession”; and its value in assessing the recovery of sediment seabed biodiversity from environmental impact

The problem of determining whether the biodiversity of an impacted muddy seabed is recovering can be resolved by drawing on a concept termed “sustainable ecological succession”. At a site impacted by discharge of mine tailings, a suite of 6 primary opportunist species (mostly polychaete worms) had started to sustain itself within 1–2 years after discharge ceased (1995), within the mix of 100+ other species which were not sustaining themselves. The start of a sustaining ecological succession is easily measurable by repeat surveys, and requires only the services of one taxonomic identifier to demonstrate the consistent presence and numbers of a limited range of species. At the assessed site, by 2000, some secondary opportunist species had entered the succession, and the species richness of the impacted area had come to equal that of the reference areas.