Collecting plants from an important forest remnant in Hawke’s Bay

In March, Te Papa’s Leon Perrie, Bridget Hatton, Julia Wilson-Davey, and Lara Shepherd travelled to inland Hawke’s Bay to collect plant specimens from Puahanui Bush, a rare lowland forest remnant.

Puahanui Bush, off State Highway 50, is an important ‘island’ of indigenous forest in the otherwise largely cleared ‘sea’ of inland Hawke’s Bay. After the Canterbury Plains, the Hawke’s Bay region has the least remaining native vegetation in Aotearoa. Plants from inland Hawke’s Bay are not well-represented in Te Papa’s botany collection, so collecting from Puahanui Bush bolstered our collections, creating a clearer record of the biodiversity remaining in this region. With the support of landowners Phyllida and Stuart Gibson, we spent three days exploring Puahanui Bush at Gwavas and collecting an example of each of the plant species we found – both native and exotic, big and small.

A history of Puahanui Bush and surrounds

Phyllida’s family has farmed the property for over a century. We were lucky to be able to stay onsite at Gwavas Homestead, which was built in 1890 by Phyllida’s great-grandfather Arthur Spry Gwavas Carlyon and has been restored by Phyllida and Stuart after being empty for 45 years. It is available for functions, such as weddings, and accommodation.

Surrounding the homestead is Gwavas Garden, a planted garden of woodland exotics, with the oldest trees planted by Phyllida’s great-great-grandfather, Major George Gwavas Carlyon who had emigrated from Cornwall in the 1860’s. Gwavas Garden is recognised as a Garden of National Significance by the New Zealand Garden Trust.

A short walk from the homestead is Puahanui Bush, where we focused our collecting. Puahanui Bush is the largest, most intact and diverse lowland forest left in Hawke’s Bay. It is a 132 hectare lowland podocarp forest that has never been logged and contains large stands of tōtara, mataī and kahikatea trees, some of which are over 600 years old. The forest is also an important habitat for native animals and we were impressed by the large numbers of birds including pīwakawaka, kerurū and tuī. Long-tailed bats, which have the highest possible threat ranking of Nationally Critical, have also been found to roost in the large trees in the forest.

Conservation of Puahanui Bush

Over the last century weeds became established in and around Puahanui Bush, with English ivy the biggest problem. When control efforts began in 1999, ivy was well established in a quarter of Puahanui Bush, with occasional plants throughout the remainder. Ivy creeps along the ground preventing regeneration of native species but also climbs up trees hindering their growth.

More recently Puahanui Bush has been fully fenced to exclude rabbits, pigs and deer. This is already making a huge difference to the health of the forest with seedlings now evident and leaf litter now building up and providing habitat for invertebrates.

Summary of our botanical finds

Over three days we collected about 280 specimens from Puahanui Bush and the surrounding area. These plant specimens increase Te Papa’s collections from the area over four-fold. We also tried to record how common each species was so future botanists can see whether species are declining or increasing over time. It will be especially interesting to examine the impact of the recently-constructed pest-exclusion fence on the vegetation.

One challenge we faced was obtaining specimens of the larger trees, such as mataī and kahikatea. For some species we managed to reach low hanging branches. However, rimu proved problematic, even eluding very long-handled loppers. Landowner Stu came to our rescue by shooting down a branch with his grandfather’s shotgun, just like was done in the old days.

Interesting finds include two exotic barberry saplings, the first specimens of these species to be added to the Te Papa collection. We also collected the second record of the large moss Braithwaitea sulcata from the southern Hawke’s Bay.

The work continues

Once we brought the plants back to Te Papa there was still more to do. The specimens needed to be dried in our drying oven, mounted on card (done by our marvellous herbarium volunteers), imaged, and added to our database.

This work is ongoing, but many of the specimens are already available online.

We are grateful to Phyllida and Stuart for warmly hosting us, Marie Taylor for the initial connection, and Kay Griffiths, who has led much of the restoration work, and local naturalist Mike Lusk for their help during our visit.