When Peter, Sue and I visited Puangiangi to look at it before buying, we could see the expected forested areas and pasture from the boat, but the landing area was inauspicious. A few big pines, brush wattle, tree lucerne, kikuyu grass and a pohutukawa, weeds or out of their natural range, were near the track from the landing bay. On reaching the edge of the first forest remnant I saw it was eaten out underneath by sheep and contained, groan, what I thought were some olive trees.
Once I’d had a chance to think and observe properly, however, I realised they were adult fierce lancewood, Pseudopanax ferox, something I’d only seen as the distinct juvenile form in gardens. This rare plant was everywhere and the project started to look like not just a restoration but also one where special plants occurred and could be protected. Things continued to improve when we found the forest sheltering the house to be reasonably sound coastal broadleaf forest, with a canopy of kohekohe, hinau, titoki, kaikomako, nikau, P. ferox and another rarity, large-leaved milk tree, Streblus banksii.
That day we also had a quick look at the farmed area, where rank grass was being slowly invaded by tauhinu, with not a broadleaved seedling in sight, and at a manuka remnant on one of the high points. A circuit in the boat before heading back to French Pass revealed several forest areas, regenerating scrub, shrublands, swathes of wharariki/flax (Phormium cookianum), cliffs and screes.
One of our earliest priorities after taking over was to do a proper ecological and botanical survey. Geoff Walls, Barbara Mitcalfe and Chris Horne came out in October 2012 for a two-day survey which turned into five when we were caught by a storm. Geoff and his family own land on D’Urville and he is a very experienced ecologist, also having visited Puangiangi as early as 1981. Marlborough District Council part-funded his visit so he could do a Significant Natural Area assessment for them. Sue and I have been privileged to spend time on field trips with Wellington Botanical Society éminences grises Chris and Barbara. The three did the most comprehensive botanical survey yet on the island, putting up with the general topography, rain, having to crawl along ridgelines as the storm hit, and still having the energy to be witty and intelligent company back at the house. Barbara was undeterred despite being high up the waiting list for a knee replacement and Chris’ supply of filthy limericks was inexhaustible.
The team compiled a list of some 138 indigenous vascular plants and made a vegetation map. The island’s ecosystems comprise:
- Coastal broadleafed forest, 15%;
- Regenerating coastal broadleafed forest, 10%;
- Mixed coastal shrublands with wharariki, 20%;
- Pasture with tauhinu, 27%;
- Kanuka and Manuka shrublands, 2%;
- Salt turfs, 1%;
- Cliffs and scarps with scattered vegetation, 25%.
(This is my slight simplification of the information in Geoff’s report and I have also tweaked the area percentages to make them add up to 100 once again.)
The Broadleafed Forest
This forest is typical of many in the Cook Strait Ecological District and Wellington residents familiar with Otari/Wilton’s Bush would feel at home with the mix of common trees given above for the forest around the house (Telecom Bush). The predominant tree is kohekohe. Soon after possum and rat control began at Otari, Sue and I began finding strange black fruits on the ground. I had never seen a fallen kohekohe fruit, as possums ate nearly all the flowers and rats got any fruits that did develop. The kohekohe are a real feature of Otari now pest numbers are way down. Puangiangi has never had possums and no longer has rats, and it is such a pleasure to see the kohekohe trunks in early winter, covered with white flowers, to be followed by copious fruits in summer. The multi-stemmed trees have great character, hanging on on the steep and sometimes mobile slopes, their canopy shorn off by salty gales.
L-R: Kohekohe flowers, June; carpeting the ground; fruit, December
In the northeastern forest, which has stabilised screes, boulders and vertical slabs and must be near the slope limit to have vegetation cover, many of the kohekohe have stopped piles of rolling rocks on the uphill sides of their trunks. They have marched up to gain the ridge in a couple of places and hang on in the 150 km/h gales, making little oases of relative calm. They share the northeastern forest canopy mainly with akiraho (Olearia paniculata), a particularly indestructible giant tree daisy, and fivefinger (Pseudopanax arboreus), the only other Pseudopanax apart from P. ferox on the island, which is a little surprising given the species diversity elsewhere in the district. There are also some karaka, ngaio, Streblus, mahoe, tree broom (Carmichaelia odorata), wharangi, puka (Griselinia lucida) and kohuhu in the canopy. The puka are very large and terrestrial, and their grooved trunks/roots snaking up and down the rocks are a highlight. The kohuhu (Pittosporum tenuifolium) is another Cook Strait special, with its salt-resistant leaves being much more leathery than in the mainland form.
Under the canopy and in open spots, kiekie forms swathes which slow progress for those intrepid enough to explore the forest. The rockier areas have gardens of rengarenga lily, which of course also extend to the open cliffs. Lara Shepherd at Te Papa has been doing a DNA analysis of rengarenga from around the country, and a specimen from Puangiangi has the same provenance as others from the northern South Island area, likely deriving from early Maori plantings of material brought from the North. There are a few lianes, with Metrosideros perforata adding some colour to proceedings. The forest floor is populated with a typical array of ferns- Asplenium, Blechnum, Microsorum, Polystichum, Adiantum,and one of Sue’s favourites, Lastreopsis velutina. Also on some of the slabs is the little Peperomia urvilleana.
The other main areas of mature forest are Telecom Bush and a large area at the south of the island. Both are on slightly gentler ground, and Telecom Bush in particular was more affected by sheep. Now the sheep have gone, there is slow but gratifying regeneration of the understory. These forests have all of the canopy trees of the northeastern forest and add hinau, nikau, tree ferns and a few tawa. Peter and I have had a fair amount of time letting gravity take us round the southern forest, looking for sooty burrows, and we were pleased to find the tiny group of adult tawa that eluded the botanists. A brief survey in 1996 by Nelson Botanical Society had however recorded a seedling tawa, so we had been hopeful of finding its parents. Summer 2016 brings several tawa seedlings to the forest with regular though light rain helping them hang on. One has even popped up in Telecom Bush and we think the kereru may also be bringing the seeds from Tinui where there is an extensive grove.
Apart from the areas of mature forest, there is substantial regeneration afoot, especially between the southern forest and the central pasture lands, and on the southwestern slopes of the island high point down to Boatshed Bay (part of the area covenanted with QEII National Trust by Ross Webber in 1999 and retired from grazing then). These areas are dominated by fivefinger, akiraho, ngaio, mahoe, kawakawa, kohuhu. P. ferox, Coprosma propinqua, C. robusta and the hybrid between the two coprosmas. C. propinqua, tree broom, mahoe, mingimingi and tauhinu play host to the mistletoe Ileostylus micranthus, which is quite uncommon on the mainland because of selective possum browsing among other insults. It has also colonised tree lucerne, introduced around the house and slowly spreading elsewhere. On the non-native, leguminous host the Ileostylus can reach 3 m across in a lush, dark green as opposed to the often more “natural” pale yellow-green on the native hosts. Most of the forest trees are beginning to make an appearance, with the first kohekohe having just shown up in the covenanted area. The regenerating forest is extraordinary in its diversity and productivity, the abundant fruiting of the fivefinger being of special note to us and I expect the birds. It has come back quite quickly as the accompanying photos from 1981 and 2012 show.
Barbara and Chris are strongly of the view that this regeneration neither needs nor wants human assistance. Their philosophy is perhaps derived from the project at Hinewai, where nature is left to take its course no matter how long or short that might be, and they certainly don’t recommend the more extreme replanting interventions which Chris recently likened in a Letter To The Editor to little more than “gardening”. I share their view for the Puangiangi project, where unassisted regeneration is doing very nicely thank you. We might however temper this with a little bit of moving of kohekohe seedlings around the edges of Telecom Bush, which have been planted with shelter trees native and exotic and gardened in the past, and which might benefit from a bit of evening up of the species present.
The Stable Shrublands and Salt Turfs
The northern end of Puangiangi and some of the other ridgelines are a delight. Here the winds are too extreme for the broadleaved forest to take over any time soon, and the land is covered with a waist-high biodiversity treasure trove.
The Cook Strait endemics shine, with three little mahoe relatives to the fore, Melicytus aff. obovatus “Cook Strait”, M. aff. novaezelandiae “Maritime” and a hybrid between them (identifications courtesy of Peter de Lange from specimens provided by Barbara). Here we also find P. ferox, Coprosma propinqua, taupata, ngaio, prickly mingimingi, wharariki, and clumps of dark green which we were excited to find was Cook Strait kowhai. It not only grows in the tangle of the more mature shrublands, but dominates some of the cliffs of harder rock down to within 20 m of the sea. Last winter I took the kayak out in the late afternoon and I could look up and see the kowhai flowers glowing yellow on the cliffs. If I had to pick one botanical standout on the island it would be these shrublands with their thriving populations of rare Strait endemics.
At and around spot height 120 m in the middle of the island is an area of manuka. Outliers have colonised the surrounding pasture on the western side down to near sea level. This part of the island is of gentler contour, being merely steep rather than precipitous. It would once have held the broadleaved forest we see elsewhere today, perhaps supplemented by a few missing trees such as matai and miro which occur on some other islands in the area. The forest cover might have helped the relatively large catchment there to have held water nearly permanently instead of ephemerally as today. The number of young manuka popping up and the relative absence of competing broadleaf seedlings (which were eaten by the sheep) might mean that the area of manuka shrubland expands and dominates the central third of the island for many decades. We need only look across the channel to Tinui to see how effectively manuka can come back on retired pasture.
An area of kanuka dominates the 128 m summit of Mt Mistaken above the southern broadleaf forest and is spreading down the western slopes. Some of the kanuka at the very edge of the forest are large and old, and their copious litter makes great robin territory. The lower plants on the very exposed areas are festooned with the rare mistletoe Korthalsella salicornioides, its stems blending very well with the kanuka foliage. I was aware that it might be around, but still managed to walk past the main colony about eight times before Chris and Barbara spotted it on their first outing. It’s likely that kanuka will be the dominant species here for a very long time.
Another rare plant found in the shrublands and open spots is wind grass, Anamanthele lessoniana. It was also obviously a favourite of Ross’, as he planted it around the house for low shelter and ornament, with its lovely showing of the wind through its blades and its seed-bearing tillers up to 2 m long. It’s fair to say that Puangiangi is also a national stronghold for Anamanthele.
At the southwestern corner of the island is an area of salt turf relatively unmodified by sheep. If Ross Webber or earlier farmers had ever had cattle it might have been lost. Here in the spray zone is a big area of silver tussock, native iceplant, glasswort, Samolus repens, Selliera radicans, Senecio lautus, and the two native daphnes Pimelea prostrata and P. urvilleana. These plants also occur sporadically around the shore and on open ridges. A monocultural salt turf of the little buttercup Ranunculus acaulis is at Woolshed Bay, by an archaeological site containing argillite, human-transported stones, charcoal and small bones. This area is more degraded by heavier grazing.
Cliffs and Scarps
Most of Puangiangi slopes very steeply away into the sea. Although Ross told me he used to muster one of the very steep eastern faces on foot, we confine our interaction to views through binoculars or at the end of a rope drilling and poisoning some of the more easily accessible coniferous weeds.
The mobile scarps of scree and softer rock may once have held a forest of sorts, but at the moment they are limited to a few patches of grey scrub. From below, the largest scree looks devastated, the shoreline littered with boulders which appear recently arrived and a more or less constant stain of sand and mud in the sea. On a gentler bit, an island of forest hangs on- or has colonised, I don’t know which.
Where slope, soil or aspect allow, the steeplands in the spray zone have extensive fields of low vegetation, dominated by wharariki (Phormium cookianum), silver tussock and with patches of rengarenga lily and linen flax (Linum monogynum). The latter two add a splash of white during flowering in spring. The shrubland species described earlier also make inroads. There are a few areas of hard rock cliffs, sometimes hosting rengarenga and Cook Strait kowhai.
Pasture
The central third of the island has gentler slopes and more shelter and it’s logical to see the influences of past farming lingering there the longest. When we took over we were nonplussed to find a flock of some 20 sheep, left to their own devices for some years. It was obvious from a restoration point of view that they had to go, but having established that they weren’t suffering through disease burdens, lack of water or sweltering in their enormous fleeces (which they were shedding), we decided to shoot them at the rate we could eat them. Sue’s family and our friend Jan from Toronto would be among the few to say they have had a Christmas dinner of the now-extinct Puangiangi sheep. Some of the older rams took a bit of cooking but I think it showed respect not to waste them. I also sent up a choicer lamb cut to Ross in Auckland.
By 2012 the pasture had become rank even with the sheep that were there. Tauhinu was all but the only coloniser, the sheep leaving it alone in favour of any broadleaf seedlings that came up. I bought from Television New Zealand some archival footage of a visit one of their journalists paid Ross as he was preparing to leave in 2004. Even at that stage he had the journalist out grubbing tauhinu.
By the time we arrived, the tauhinu was extensive but we could still walk anywhere in near enough a straight line. Now it is all but impenetrable in many places, manuka is spreading from the high point and broadleaf saplings are showing in the shelter of the tauhinu. We recently cleared some grass and tree lucerne at the edge of Telecom Bush and were surprised to find healthy kohekohe seedlings under the rank grass.
Weeds
At the start of this article I implied an initial negative impression of the island’s botany, formed by a weedy landing but since fixed by exploration and experts. Really though, we are pretty lucky having only the weeds we do. There is no gorse, Darwin’s barberry, hakea, climbing asparagus, old man’s beard, and so on. The ones we do have are isolated and controllable, and this influenced our decision to totally eradicate them apart from tree lucerne, pasture weeds (which will eventually die out as the forest grows) and probably kikuyu grass which is stabilising land at the two beaches for the time being.
A shelter belt of macrocarpa protected the country’s smallest woolshed (3 x 2 m) and its yards, dating we think from the King-Turners’ 1929-1957 tenure. The shelter belt itself was benign but seed was blowing on to the adjacent rock pavements and cliffs, and some sizeable trees had taken hold. Lest the island end up like coastal northern California, we engaged Marlborough Sounds Restoration Trust to spray the macrocarpas from the air with metsulfuron methyl, as they have been doing successfully with pines in the Sounds for some time now. We drilled and poisoned the accessible trees, one of which got its own back by blowing over and flattening the woolshed. Some of the trees are not dead yet after two visits from the helicopter and there are plenty of seedlings coming up, but we will persist. The house area held several large pines, presumably for shelter and firewood, and they have also been poisoned. Many have blown over now and some took out the access track when they did so. We have cut a hundred or so saplings from the covenant area, where the seeds appear to blow and take hold, and we are seeing only a very few now.
A single pohutukawa, presumably an ornamental planting, and an isolated pocket of European broom have also been dealt with, apparently without any ongoing seedling germination. An infestation of brush wattle around the house was cut down. The main area of wattle has now been taken over by regenerating shrubs and it is too shady there for any wattle seedlings. Further down-slope, the long-lived seeds mean regular attention is required to pull out seedlings, a thousand at a time if this month is anything to go by.
Outlook
All said and done, this is a botanical restoration that is proceeding very quickly with minimal effort from people, and it is reasonable to think that Puangiangi will be weed-free, and have at least developing forest over the former pasture lands, in my lifetime. The broadleaf forest will have a resilient structure with a diverse understory, and the island will become more widely known as a national stronghold for its astonishing range of rare endemics.
Fauna Recovery New Zealand 