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The gully system

The Mangakotukutuku is one of four major Hamilton City gully systems that are currently the focus of efforts to re-establish significant areas of native biodiversity in the urban environment (Clarkson & McQueen 2004). Collectively, Hamilton's gullies make up 8% of the city area and they have been described as the "best kept  ecological secret of Hamilton City".

Animal life

A range of native birds, bats, lizards and invertebrates have been seen in the Mangakotukutuku gully system.

Invertebrates include puriri moth, glow worms, the giant bush dragonfly, and tree weta.

During our 2007 bird survey in Sandford Park we found the following native species: fantail, harrier hawk, silver eye,   grey warbler and kingfisher (kotare). Other native birds seen in the area include  white-faced heron and ruru (morepork). Click here to find out more about these and hear their calls).

Vegetation 

From the name of the stream alone we can be reasonably confident tree fuchsia grew along the Mangakotukutuku Stream (Manga – stream, kotukutuku – tree fuchsia). We know of at least one kotukutuku that remains and encourage you to plant at least one more. Of course, with the area's moist climate, mild winters (relatively) and young free-draining soil, a great diversity of other native plants await the chance to grow in your gully.
Puriri moth

Prior to people arriving in Hamilton (and in between eruptions, glaciation and sea level rise), Hamilton and its gullies were cloaked in forest - tall, lush forest unlike any known to the continents and islands of our ancestors. Kahikatea, matai, rimu and mahoe to name a few of the trees, with ferns, astelias and coprosmas closer to eye level (see Botany of the Waikato for more detail). Take a walk around Claudelands Bush (Jubilee Park) and Hammond Bush (Malcolm St) to get a feel for what covered the city and its gullies.

Not surprisingly, these growing conditions are also ideal for pasture and cropping. That is why almost every spare inch of Hamilton was cleared by settlers. The gullies did not escape fire and axe, and presumably were grazed long enough to destroy much of the seed bank of native plants. Eventually the sheep, cows and goats made way for people, our houses and our gardens. 
Key ecological sites
There are three sites with vegetation of
ecological significance within the Mangakotukutuku gully system according to Downs et al. (2000). Each of these sites is less than 0.5 ha in area. They comprise two where the tree canopy is mainly introduced species with an understory of native species, and a third site with a small stand of kanuka. These sites are:
    • privet/tree-fern forest with a solitary large pine and kahikatea on the gully bordering Te Anau Park
    • grey willow/tree-fern forest on the Peacockes branch 
    • kanuka patch on the Peacockes branch 

The Mangakotukutuku Gully and its favourable growing conditions were ripe for newcomers, and pretty garden ornamentals found themselves in seventh heaven, having being tossed over the fence. Trandescatia (wandering jew/willie), pretty morning glory, privets, nightshades and lilies spread throughout the Mangakotukutuku Gully, meeting limited resistance from a few pasture weeds (blackberry, willow, gorse).

It can be argued that native plants would eventually re-establish, in the absence of further disturbance (for example, periodic clearing tends to favour many introduced weeds). Already pockets of tree ferns (mamaku, wheki) can be seen re-establishing in the Mangakotukutuku Gully. However, it is difficult to imagine the more shade tolerant exotics, such as privet and Trandescantia, stepping aside if not pushed. Restoring the Mangakotukutuku Gully’s unique and lush forest will require a careful and staged attack on the pests and weeds - bit at a time, focusing on the worst offenders first. It will also require planting initiatives to replace the weeds with our missing native plants. It is crucial to select the right native plants. There are books, people and events available to us with exactly this type of information. Read your gully guide (see link below), speak to your nurseryman, and find out what you need to know.

Managing gullies

Information on the restoration of gully vegetation is available from the Hamilton City Council website.  Some flowering trees provide food for native birds - check your gully guide or with your local nursery to see which species are appropriate for gully planting.

In terms of stream health, planting trees that provide shade, stabilise eroding banks, and create habitat diversity (e.g., stable streambank overhangs) are the most important considerations. Plants differ in their abilities to stabilise streambanks or provide cover for native fish. Secretive species such as the banded kokopu are often found under bank overhangs created by tree ferns.

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