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Trip Report – Mangarakau, North-West Nelson Summer Camp

Trip Report – 11-18 January 2017 :   Mangarakau, North-West Nelson Summer Camp


Twenty-six BotSocers attended the summer field trip based at The Outpost, Mangarakau.   Most of us were from the Wellington area, but it was great to be joined people from as far afield as Dunedin.

Myosotis aff. brockiei

Myosotis aff. brockiei (a) (CHR 497375; Lake Otuhie).
Illustration: Eleanor Burton.

We visited several very different plant habitats.   We botanised Mangarakau Swamp, coastal salt turf, Patarau River, Wharariki Beach, and picturesque Lake Otuhie.   The summit of 500-m Knuckle Hill, with its spectacular views to Farewell Spit in the north, and Whanganui Inlet to the west, was clothed in stunted vegetation not seen nearer sea level.

Although not botanically significant, the most unusual place we visited was a gigantic limestone cave that went right through the ridge above The Outpost.   We entered on one side of the ridge and popped out of the other!

It was a pleasure to host three enthusiastic botanists from DOC, namely Shannel Courtney, and the father-and-son team of Simon Walls and Rowan Hindmarsh-Walls.   They accompanied us on one of our day trips, and gave illustrated evening talks about their work.   They were thrilled to find the very rare Myosotis aff. brockiei growing on the limestone cliffs above The Outpost.   I thought that with botanists like them working for DOC, the future of our native flora is in good hands.

Organising the field trip was an interesting exercise.   During my reconnaissance of the area in December, I was initially dismayed at what I perceived to be a lack of places to visit.   There are relatively few tourists to the area, so apart from Whanganui Inlet, Mangarakau Swamp, and Wharariki Beach, there were few other places of easy access.   It was only by consulting the locals, and seeking permission to cross their land, that the full range of possibilities opened up.

I thank everyone for their support, and for contributing in so many ways to the success of the trip.   My special thanks to the land-owners, to Richard and Margaret Herbert for beavering away in the background, and sharing some of the leadership responsibilities, to Julia Stace for ensuring we were well fed at breakfast and lunch, and to Barbara Hammonds for the onerous task of collating all the many plant lists.   And lastly, many thanks are due to Greg and Rose, our hosts at The Outpost, for the excellent service and meals they provided.   Tasty desserts came from the nearby Nugget Cafe.

Chris Moore, Trip Leader.

Participants : Margaret Aitken, Robyn Bridges, Mark Calcott, Gavin Dench, Michele Dickson Raewyn Empson, Dale Every, Julia Fraser, Ken Fraser, Barbara Hammonds, Richard Herbert (deputy leader), Margaret Herbert, Jan Heine, Brenda Johnston, Allison Knight, John Knight, Rodney Lewington, Pat McLean, Pascale Michel, Chris Moore (leader), Syd Moore, Darea Sherratt, Sunita Singh, Val Smith, Owen Spearpoint, Julia Stace.

The following four field trips were to locations depicted on NZTopo50- BN23 Paturau River:

12.1.17: Mangarakau Swamp

On the first day of the summer camp we 26 were pleased to wake to a fine, if cloudy morning after persistent rain the previous day.

We crossed the road from The Outpost to Mangarakau Swamp Reserve.   This swamp comprises land purchased from private landowners in 2001 by the NZ Native Forests Restoration Trust, and land owned by DOC.   Mangarakau Swamp is the first wetland, and first South Island reserve, created by the trust.   It is managed by The Friends of Mangarakau Swamp and, covenanted with the QE11 Trust, with the aim of restoration.   It lies south of Whanganui Inlet, near the west coast of the northern South Island.

We were joined for the day by DOC Rangers, Simon Walls and his son Rowan.   They described the history of the swamp, explained something of the geology of the area, and helped us with plant identification.   A vehicle track leads through part of the wetland, with smaller tracks branching off it.   We split into 3-4 groups to botanise the wetland, and reach the lookouts to get an extensive view of the swamp.

The mature forest that once covered the wetland was kahikatea and pukatea-dominant, with a wide array of under-storey species.   Only a remnant now remains along the western edge.   This is being extended by restoration planting using local seed grown off site, sourced from the wetland.

Within the swamp area there are three dominant vegetation patterns.   The Gleichenia fern / manuka scrublands are on the drier soils, while the wetter areas are covered in rush and reed communities of Typha (raupo) and Baumea.   Within these areas there are some small lakes where the endangered Myriophyllum robustum continues to survive.   The reed-lands also have some rare plants, including the pink ladies’ tresses orchid, Spiranthes sinensis.   Simon Walls has been out on the “Big Pond” in a kayak.   He told us about the deep layer of peat under the swamp.   Anyone who stepped off the track was likely to sink to their armpits.

Trapping to control pest species is evident throughout the reserve.   In the Visitor Centre, we saw the records of all the mice, rats, possum and mustelids caught during the last twelve years.   Sighting fernbirds / matata was one of the highlights of our day.   We were alerted to them by their “U-tick” call and spotted them on the edge of the track in low manuka bush.   They didn’t seem bothered by us, and stayed close, allowing us to identify their distinctive brown- and fawn-striped heads, speckled breasts with brown wings and tails.

On another day, Robyn from The Friends of Mangarakau Swamp, took some of us to see and feed robins / toutouwai.   She had meal-worms which soon attracted a male robin with his big fluffy chick demanding to be fed.

Julia Fraser

Bibliography
Website of the Native Forest Restoration Trust, Mangarakau Wetland: http://www.nfrt.org.nz/reserves/mangarakau-wetland/
Leaflet: Mangakarau Swamp Reserve Visitor Guide, obtained at the wetland.

13.1.17: Knuckle Hill, 506m

Despite it being Friday 13th, after worshipping the full moon the previous night, we woke to a perfect day.   After 7 a.m. breakfast, and 8 a.m. briefing, we were ready to go by 8:30 a.m. to the aptly named Knuckle Hill.   We had the choice of going to the top and botanising on the way back, or botanising on the way up, and possibly not getting to the top.

We saw and heard a NZ falcon / karearea.   A red deer stag crossed the track near the summit, and we saw a nanny goat and kid on the track.   The pest animals were unfazed by our presence.

Most of us reached the top to enjoy outstanding views that included Farewell Spit, Mt Burnett, pakihi swamps and Whanganui Inlet.   We were impressed by the completely different vegetation association on the nutrient-deprived granite of the summit.

Botanical highlights of the trip included: Ascarina lucida, Gleichenia dicarpa, Lycopodium volubile, Metrosideros parkinsonii, M. umbellata, Sticherus cunninghamii, Thelymitra cyanea, three species of Dracophyllum, Weinmannia racemosa, and the new species of Kunzea that looks like Leucopogon fasciculatus.

Some people explored Kaituna Track where Alison and Mark found many lichens in regenerating rimu forest.   Also on the Kaituna Track, but beyond the Knuckle Hill turnoff, Jan, Owen, Pascale and Raewyn noted the changes in vegetation and soil fertility corresponding with changes in the basement rock.

Despite a passing shower at lunchtime many returned happy, but sunburnt.

Brenda Johnson.

14.1.17: Salt Turf

Following a morning in the bush, everyone was keen to get to the beach, and sand turf.   And what luck!   There was no wind, and only a little moisture.   We parked the cars about 500 m beyond the bridge over Sandhills Creek then followed a sheep track down a small gully spilling through the sand hills to the beach.   We rapidly spread out, heading north to the limestone outcrops just south of the mouth of Sandhills Creek, as we had been advised that the sand turf there could be good for foraging.

On the sand-hill banks behind the beach a few people searched among the sparse common plants, and admired a native plantain.   At the cluster of limestone monoliths, bluffs, tongues and small reefs, our searching intensified among the hollows, grooves and cracks supporting mostly gnarled taupata, flax, pohuehue, two spleenworts (Asplenium obtusatum and A. oblongifolium), Dysphyma australe and a small Veronica (Hebe).   One large tongue of limestone, with a gently sloping ledge top, ending in a dangerous overhang that became the main focus of our attention.   We accessed it by climbing up near the back edge on to pasture, then heading back out through the marram grass area, then a band of shin-high, dense, beautifully wind-trimmed, flowering Metrosideros perforata, on to the flatter slopes, densely covered with a carpet of mat-forming turf.   Here was an amazing variety of many species of tiny coastal plants.

Some of the special gems were the endemic and uncommon species Wahlenbergia congesta, Leptinella calcarea and Ranunculus recens var. recens, the declining Myosotis pygmaea var. pygmaea and the threatened Lepidium flexicaule.   Catching the eye too were several Thelymitra spp. with leathery leaf and capsule, only 2-3cm tall and the red fruits of a Nertera.   It seemed inappropriate that we should tread on this beautiful carpet, but considering how few others might ever venture there, the sturdy little plants might be OK.

Michele Dickson.

15.1.17: DOC reserve behind The Outpost

This sortie to the limestone bluff and cave above The Outpost was intended to be a leisurely day!   After heavy rain at dawn, by 9 a.m., the mist was clearing and a fine day was ours.

Asplenium lepidotum

Asplenium lepidotum.   Photo: (c) Alex Fergus (Creative Commons Licence CC BY 4.0, https://creativecommons.org/licenses/by/4.0/legalcode)

The “cavers” and limestone-bluff botanists left at 9:45 a.m. with DOC botanists Shannel Courtney, and Simon Walls and Rowan Hindmarsh-Walls.   Greg (our host at The Outpost) led the way immediately up onto mud slides, slithering uphill with two steps up and one or two down!   Eventually we got up through the native forest to the pine plantation, and across to the cave.

The first group, with Greg, went through the big cave festooned with stalactites and stalagmites, and bullock and moa bones.   Smaug from the Hobbit lurked there rearing up its log-head.

The next group of “deep botanists” got stuck on the bluffs where they found Myosotis aff. brockiei (a) (CHR 497375; Lake Otuhie).   (This was a new population of the plant, so the find was exciting).   Other plants of note were Veronica stenophylla var. hesperia, Asplenium lepidotum, and Brachyglottis hectorii which was in flower.

Our slither home was easier than expected using supplejack, and demolishing the odd mahoe.   We dribbed and drabbed back over two hours, arriving late afternoon with clothes and legs caked in slimy mud.

The alternative trip was to the swamp, with Robyn Jones from the Mangarakau Swamp Trust, to search for robins.   With a little treat of mealworms, two robins hopped up to say howdy.   And another treat for the group was seeing fernbirds.

The evening’s meal of succulent roast lamb, potatoes, and kumara went down a real treat.   A berry crumble followed.

Jan Heine

16.1.2017: Lake Otuhie

The day dawned cloudless but with strong winds.   We began botanising at Sandhills Creek bridge.   Chris had arranged with the farmer that we could use the main farm access road up the valley, saving us having to cross the stream to botanise the more interesting and forested north side of the lake.   We slowly botanised up the road along the base of limestone bluffs, recording as we went.   We almost immediately saw the newly described Asplenium lepidotum with its distinctive black scales.   The bluffs had eroded in such a way as to leave striated terraces on which grew Poa anceps, Coprosma robusta and Hebe stenophylla var. stenophylla, Olearia avicennifolia, Coriaria arborea var. arborea.

Lagging behind the rest, Pascale, Julia and I worked our way along the road, then across the wetland paddocks filled with Galium propinquum, Juncus edgariae, Rumex acetosella and Carex eragrostis.   Once across the valley and over the small but very deep stream, we went along the base of the limestone bluffs on the north side of the valley.   At the start we encountered Coprosma areolata, C. propinqua, C. rotundifolia, C. rhamnoides, and Ileostylus micranthus growing out of the top of the compact bushes.   South across the valley towards the stream was a swamp forest of Laurelia novaezelandiae, Rhapalostylis sapida, with occasional Dacrycarpus dacrydoides and Cordyline australis.   Crossing the boundary fence into Kahurangi National Park, there was an immediate increase in the density of regenerating native species, with the whole suite of species you would expect to find, including some more local endemics e.g., Hebe townsonii.

The botanising groups had lunch at various sites, some in the bush, some on the grassy slopes above the lake, and some higher up among the bluffs.   Simon Walls from DOC had given us a talk about the area, providing hints on where to find uncommon species.   After lunch, the groups headed up towards the bluffs and taller forests.   Barbara H had the finds of the day with an endemic Myosotis sp., Melicytus “Burnett” and Lepidium flexicaule, all either on, or just under, the bluffs.   The Lepidium was growing along a narrow strip at the base of the bluffs where there was just enough light and water.   Gavin found Manoao colensoi, Rodney and Darea found Hymenophyllum scrabrum, and Pascale and I enjoyed the forest at the bend in the lake amongst large Lauralia novaezelandiae, Metrosideros robusta, Pittosporum cornifolium, Dacrycarpus dacrydioides and saw much pig rooting.

At 3 p.m., people returned to the cars, then drove to Big River for a short potter.   We had had another very different and memorable day.

Owen Spearpoint


 

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