The Estuary Restoration Project is a long term project, and we are focusing initially on the
northern section of the estuary near the DCC landfill.
Background and Issues
The Dunedin Environment Centre Trust (DECT) began restoring native bush to the land
around the Green Island Landfill in 2009.
Of the original 120 hectares of saltmarsh that was the Kaikorai Estuary, around half has been
covered in landfill, starting in the early 20th century and continuing to this day where the
privately owned landfill on the southwestern side of the estuary carries on building up and
extending it’s footprint onto low-lying territory.
A significant portion of land in the estuary is now City Council land allocated ‘special
purpose reserve’ status intended to allow the Council to dump rubbish on it, or to be kept as a
buffer between the dump and urban areas.
Much of this land is in exotic pasture grass and was being grazed up until our involvement.
Some of the land has been invaded by willow trees, including patches planted in natives in
2000 by NZTA as mitigation for the damage caused by building the Fairfield bypass.
Willows are a major threat to the conservation values present as they smother smaller stature
native saltmarsh and riparian trees and shrubs and consequently remove habitat for many
native estuarine edge birds and invertebrates.
The mudflats have been frequently tested for contaminants , eg lead, and these are often
present, although not terrifically high loadings are found.
Values
23 bird species have been identified here and 5 fish species, including both native eels,
longlined and short finned. These are both considered threatened species and so habitat
containing them has biodiversity significance. It is no longer a suitable mahinga kai source
unfortunately.
There are several hectares of saline plant communities, and of makaka (marsh ribbon wood).
As part of mitigation for building the bypass, several ponds and small islets were constructed
for their potential public amenity values. These mainly retain their scenic qualities.
Planting
DECT started planting in the northern section of the DCC Special Purpose reserve in 2009,
with the support of the Dunedin Central Rotary Club. Several groups including the Rotary
Club and DOC Conservation Corps assisted in removing or controlling willows in the
northern area.
Mature willows were cut down next to the landfill access road in 2009 and that area replanted
that year.
Plantings have extended 400m to the south along riparian areas over the past ten years
and so far thousands have been established. Flooding and digging by pukeko have caused
damage to plantings at times, sometimes hundreds have died in single events.
Thousands of native plants are scheduled for enhancing the reserve over the next two years.
We look forward to your help in this great project!