News article

New report on effects of sediments on birds

A report on the effects of sediments on coastal birds was commissioned by the Department of Conservation and has just been published. In it the known effects of marine sediment on New Zealand’s 87 seabird species and 47 shorebird species were discussed in this report. Knowledge gaps were also highlighted.

Known effects of sediment

Sedimentation events are both cumulative, where sediment accumulates slowly over time, or catastrophic, where sediment is rapidly deposited, often following severe rainfall. Both types affect seabirds and shorebirds.

The report notes that there is relatively little published literature about the effects of sediment on birds. Some information is available about how:

  • turbidity caused by sedimentation can affect seabirds that hunt visually, including terns, shags and penguins
  • sedimentation can indirectly affect seabirds and shorebirds by affecting the marine food web (especially macroinvertebrates)
  • sedimentation reduces light penetration, smothers the seafloor and changes the composition of marine ecosystems.

Use of the Resource Management Act to address sedimentation

The effects of sediment have been addressed with the Resource Management Act in several different situations. Examples included in the report are:

  • Okura Estuary urban development
  • forestry in the Marlborough Sounds and its impact on king shags/kawau
  • sedimentation in the southern Firth of Thames and its impact on shorebirds
  • regional and district plans in Otago and yellow-eyed penguin/hoiho foraging
  • New Zealand fairy terns/tara iti and mangrove removal
  • coastal birds in the Motiti Natural Environment Management Area
  • sand mining at the South Taranaki Bight
  • dredging of Port Otago and its impact on coastal birds.

To read more and/or to download the report go here, from where these words were taken.