Leave mining waste (tailings) in place following cessation of disposal operations

How is the evidence assessed?
  • Effectiveness
    15%
  • Certainty
    25%
  • Harms
    5%

Study locations

Key messages

  • One study examined the effects of leaving mining waste (tailings) in place following cessation of disposal operations on subtidal benthic invertebrate populations. The study was in Auke Bay (USA).

 

COMMUNITY RESPONSE (1 STUDY)

  • Overall community composition (1 study): One replicated, paired, controlled study in Auke Bay found that plots where mine tailings were left in place had similar invertebrate community composition as plots where tailings had been removed, but both had different communities to plots of natural sediment.
  • Overall richness/diversity (1 study): One replicated, paired, controlled study in Auke Bay found that plots where mine tailings were left in place had similar invertebrate species richness as plots where tailings had been removed, but both had lower richness compared to plots of natural sediment.

POPULATION RESPONSE (1 STUDY)

  • Overall abundance (1 study): One replicated, paired, controlled study in Auke Bay found that plots where mine tailings were left in place had similar invertebrate overall abundance and biomass as plots where tailings had been removed. While plots with and without tailings had similar abundances to plots of natural sediment, their biomasses were higher.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

  1. A replicated, paired, controlled, pilot study in 1994–1996 of 90 plots of soft seabed in Auke Bay, Alaska, USA (Kline & Stekoll 2001) found that leaving mine tailings on the seabed after ceasing disposal operations, or removing them, led to similar changes in invertebrate community composition, abundance, biomass and species richness, but either way remained different to nearby natural communities, after 22 months. After 22 months, invertebrate community compositions were similar in plots with and without tailings but remained different to plots of natural sediment (data presented as graphical analyses). Plots with and without tailings had similar invertebrate abundance (with: 900 vs without: 1,050 individuals/tray), biomass (370 vs 380 mg/tray), and species richness (50 vs 48 species/tray). Plots with and without tailings had similar abundances to the natural plot (natural plot abundance: 920 individuals/tray), but their biomasses were higher (natural plot biomass: 150 mg/tray,) and richness were lower (natural plot species richness: 40 species/tray). In 1994, 48 plastic trays (as experimental plots, 8 cm deep, 15 cm diameter) were filled with either tailings or sediments without invertebrates (to mimic removal of tailings) and deployed in pairs by divers at 21 m depth in a circular arrangement (30 m diameter). After 9, 17, and 22 months, 10 trays/treatment were recovered (in total: 30 of the 48 trays), and 10 plots of nearby natural sediment were sampled using a tray as a corer. Invertebrates (>500 µm) were identified, counted, and dry-weighed.

    Study and other actions tested
Please cite as:

Lemasson, A.J., Pettit, L.R., Smith, R.K. & Sutherland, W.J. (2020) Subtidal Benthic Invertebrate Conservation. Pages 635-732 in: W.J. Sutherland, L.V. Dicks, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2020. Open Book Publishers, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

Subtidal Benthic Invertebrate Conservation

This Action forms part of the Action Synopsis:

Subtidal Benthic Invertebrate Conservation
Subtidal Benthic Invertebrate Conservation

Subtidal Benthic Invertebrate Conservation - Published 2020

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