Fallen tree used to improve native fish habitat at Belfast Reserve

Last Updated : 10 May 2021
Fallen tree used to improve native fish habitat at Belfast Reserve

Parts of a large fallen pine tree that needs to be removed at the local Belfast Reserve will be used to enhance in-stream native fish habitat.

Belfast Reserve has very high ecological value is home to a raft of native flora and fauna.

During the removal of the pine tree, parts of the trunk and some branches will be placed in the park's stream to provide daytime cover for native fish species. 

The well-used track will remain closed until the work is complete.

Belfast Reserve 1

 “This is a tricky job," says Jason Davis, Senior Arborist. "The tree needs to be removed carefully, minimising any damage to the surrounding vegetation and making sure that any tree parts left on site won’t cause future flooding when introduced to the stream,”

“The stream occupies a deep gully which, along with its steep streambanks, make anchoring wood in the stream tricky.  While this will restrict us to placing wood at a few key locations, it is a worthwhile endeavor. This is because wood is an excellent material when it comes to creating daytime cover for native fish species."

This is especially important given how tiny Tāmaki Makaurau’s streams are relative to the large size of the fish that use them.  

Fallen tree used to improve native fish habitat at Belfast Reserve (1)

A ‘tidy’, uncluttered stream does not translate into a flourishing native fish community, says Auckland Council’s freshwater ecologist Matt Bloxham. Large-bodied whitebait species (kōkopu) and eels (tuna) struggle to conceal themselves as they grow in Auckland’s high modified, and often channelised urban streams.

Auckland Council is working with community ‘stream teams’ across Auckland to add wood to streams to improve fish habitat and enhance ecosystem functionality. Logs, tree roots and branches also influence 'instream structure' and create localised areas of stream deepening and hiding places which help our mainly pool-dwelling fish fauna.  

“Depth variation is something that is so often absent in urban and pastoral streams for the simple reason; our stream margins are so often bereft of woody tree species,” says Auckland Council’s freshwater ecologist Matt Bloxham.

Local Friends of Belfast Reserve have welcomed this work as it protects the local stream and marine life. The group works to protect the park’s ecology and has also observed kereru which were absent in October-November 2020 return to the reserve over the summer. While they’ve started to move on for winter, two pairs of magpies have decided to stay put.

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