Rhythm of the wetland

Forest and Bird, Issue 306, 1 November 2002, Page 36

Rhythm of the wetland

SARAH GIBBS

— SARAH GIBBS

visits Forest and Bird’s Matuku Reserve, now part

of a restoration programme in the ranges west of Auckland.

Partially protected by the forested hills of Matuku Reserve, the Te Henga wetland is the largest relatively unmodified freshwater wetland in the Auckland region. In summer, it is awash with brilliant green raupo with silver rippling across open blue-green ponds. In autumn the green becomes progressively tinged with a rich russet red as

the raupo succumbs to winter frosts. Around 20 hectares of this wetland lies within the Matuku Reserve and can be accessed by a boardwalk. In spring, the metallic duet of fernbird pairs can be heard, while the resounding boom of matuku, the bittern, punctuates the constant whisper of rustling raupo. The vegetated areas are also interesting for, although they look like solid islands and peninsulas, many are in fact floating pontoons of vegetation more than a metre and a half thick. When Forest and Bird first acquired Matuku, the wetland was covered in an almost continuous mat of this floating vegetation and there were no large areas of open water. This all changed on July 1, 1979, when heavy rain coincided with a spring tide at Bethells Beach, downstream, and a full Waitakere reservoir, upstream. With the water table already high and drainage impeded by the high tide, the valley flooded dramatically. For about a day, only the tops of the cabbage trees could be seen above the water and Matuku’s volunteer ranger, John Staniland, says it was the one and only time he has ever seen fernbird in the forest area. The flood rolled up huge carpets of floating vegetation and swept them into the sea, creating large open ponds within the wetland. Within 24 hours the floodwaters had receded, but the ponds have remained, resulting in a mosaic of habitats that attracts

a wide range of water birds. Rising above the wetland, nearly to the ridgeline of Jonkers Road, Matuku Reserve protects round 80 hectares of northern coastal forest as well. Embracing the steep slope of the widest valley in the Waitakere Ranges, Matuku is the Society’s secondlargest reserve. More than 300 species of plants have been recorded, along with 45 bird species (five of them threatened), six species of native fish, one native lizard and numerous insect species. A platform near the top of the reserve offers expansive views over the forest, wetland and out to coastal headlands. There is also a spectacular cliff view down a waterfall valley to lush lowland forest, including a grove of around 200 nikau. A

track system offers a choice of walks from one to three hours. These include a 60metre boardwalk through the wetland and the experience of walking behind a waterfall. Those visiting the reserve on a branch field trip are also able to climb many metres up a ladder to a tree platform high in a puriri tree, where the Entomological Society and Landcare Research carried out a sampling programme for arboreal insects. The acquisition of Matuku by Forest and Bird is unique in that it was acquired in four sections, and each section was acquired at different times and in a different way. The first block of the Matuku Reserve was purchased in 1979, after an area of forest adjacent to the regionally significant Te Henga Wetland was put on the market and a number of prospective buyers were considering using the area for grazing. Forest and Bird’s National Executive and Council gave half the money required for

the purchase of the initial block, on the proviso that Auckland branches raise the balance. A three-year fund-raising programme was initiated, but the money was raised within three months. When an adjacent 20-hectare block became available in 1985, Waitakere branch fundraised for half the purchase price — with renowned Auckland botanist Lucy Moore being one of those who made a donation. The QEII National Trust provided the other half on the condition that the entire block be covenanted. The 16-hectare third block was acquired through a land swap in 1990. Forest and Bird exchanged a two-hectare block on the other side of the road for 16 hectares of forest that was adjacent to the existing reserve and ran down to the wetland. The next 20-hectare block was purchased by the Society in 1994, with the Nature Heritage Fund providing half the purchase price. With the current acquisition of 20 hectares (see box, over), Matuku Reserve now protects 120 hectares. When Forest and Bird purchased Matuku, damage from a herd of around 50 goats had resulted in a thin understorey of unpalatable species. Possums were taking a toll of the canopy. Larger insects were scarce and

birdsong, as in other parts of the Waitakere Ranges, was faint. An adjacent farmer was approached about

Waitakere Forest and Bird is extending the Matuku Reserve with the purchase of nearly 20 hectares upstream of the present blocks. It comprises forested hillside falling to the Waitakere River. Purchase has been assisted by the Government's Nature Heritage Fund which granted $140,000 but Waitakere Forest and Bird has to raise a further $25,000.

the goats. He offered to assist by fencing the herd out of the reserve and onto his farmland. Within around seven years parts of the understorey that could be seen through easily became so dense that it was not possible to push through much of it, and for many years it seemed that it would remain like this. Over the last five years, however, the understorey has been opening up again — but this time for the right reasons. These species have now matured sufficiently that it is possible to see through the forest again. Improved forest health is also reflected in a much wider range of understorey species. Restoration at Matuku also includes control of possums and rats. Bait stations have been placed at 100-metre intervals along lines 150 metres apart. Branch

volunteers keep these stocked with talon provided by Auckland Regional Council, which has resulted in very low rat and possum numbers. Possum numbers are kept low also due to low reinvasion thanks to ‘Operation Forest Save’ — a successful possum control programme the Auckland Regional Council runs throughout the entire Waitakere Ranges. Recently pest control has been expanded to include stoats

and other mustelids, which are trapped in kill traps. The result has been an increase in life within the forest. Invertebrate numbers have bounced back particularly quickly, and bird species are now following suit.

is the northern field officer for

Forest and Bird. Matuku Reserve may only be accessed from Snow’s Lane off Jonkers Road.