Ecosystem explorations

Photo credit: Gay Munro

Active sand dunes

When the sun is shining, it is a great time to go to the beach and discover active sand dunes. It's best to choose a calm day to explore active sand dunes because, as their name implies, they are very mobile and on windy days loose sand is picked up and moved around. This means the shape of the dunes is always changing. The constant movement makes it very hard for plants to establish so only specially adapted plants like pingao (Ficinia spiralis) can survive on active dunes.

Pingao has long, thick stems that help give it stability in the shifting sand and help it tolerate being buried by sand. Its long golden leaves are often used for weaving. Unfortunately sand dunes that blow around and change every few months are hard to farm and manage, so over the years Southland's sand dunes have been stabilised and tamed, by planting exotic marram grass. Active dunes are now nationally rare and threatened.

Southland is lucky to still have active sandy dunes, which have an important role to play. The active dunes can act as barriers from storms and coastal flooding because they are able to move and 'catch' the force of the storm. Due to the introduction of exotic weeds, active dunes can be hard work to maintain but it's not just humans that benefit. Stewart Island Rakiura and the Fiordland coast have some of the most intact sand dune systems in New Zealand making Southland the national stronghold for some threatened plants including pingao, sand tussock, the buttercup Ranunculus recens and mat daisy Raoulia sp. aff. hookerii.

On Stewart Island Rakiura, the active sand dunes are a feeding ground for kiwi that probe the loose sands for sandhoppers and other insects, whilst over at Martins Bay in Fiordland the active dunes are the breeding grounds for many shore birds such as oystercatchers and banded dotterel. Geckos and skinks also inhabit the dunes.

Southland active sand dunes to explore

• Martin's Bay, Fiordland
• Masons Bay Stewart Island

Photo credit: Kelvin Meade

Diagrams courtesy of the Coastal Restoration Trust of New Zealand.

Kahikatea swamp forest

Kahikatea or white pine forests are great places to cool off over the summer months. As New Zealand's tallest tree, kahikatea provide ample shade and their love of wet ground means they are often associated with water, either on river edges or in swamps. The cool moist understory is often draped in lichens and mosses, giving the forest a mystical feel.

In late summer and autumn, the mottled green of the forest gets sprinkled with a red-orange shine as the kahikatea seed cones mature from green to red. These seed cones were an important food source for Maori who harvested them. They also feed kereru and other native birds.

The tall straight nature of kahikatea made early European settlers think the trees would make perfect ship masts, but the wood rotted too quickly for ship building. The wood was found to be free of odour and taste, making it ideal for storing and transporting food. Kahikatea forest all over the country were felled to became 'butter boxes'.

These days the moisture loving nature of kahikatea makes it a useful tree for erosion control, and its frost hardy nature makes it a prime candidate for riparian planting projects. Its tall stature and relatively quick growth contributes to carbon sequestration.

Large areas of Southland would once have been covered in this type of forest swamp and birds and insects would have filled the air, attracted by the small but plentiful fruit. The large scale swamp forest would have slowed the flow of the floods reducing their effects.

Only small pockets of this once rich ecosystem are left but you can take a step back in time and walk through kahikatea forest at Kew Bush or Thomsons Bush.

Photo credit: Chris Stowe

Marine mammal haulouts and sea bird burrowed soil

It's not easy swimming all day and sometimes marine mammals just need a rest. Species such as New Zealand sea lions and fur seals rest by hauling themselves up on to the shore. Their favourite resting and breeding areas are called haulouts and generations of use by marine mammals have given them a distinctive ecology and smell!

Haulouts are one of the only natural ecosystems in New Zealand that require the presence of large mammals to exist. Year-on-year use by the heavy animals compacts the soil and excrement from hundreds of animals builds up nutrient levels. Only specially adapted plants can live in these conditions and several threatened plants are associated with haulouts including several species of scurvy grass (Lepidiumspp). These grasses were an important resource for early sailors who used them prevent scurvy on long sea voyages.

Sea birds need to come to land to breed. Species such as titi (sooty shearwater) form large breeding colonies and their burrows, trails and tracks can transform the landscape. These areas are now rare on the mainland, but intensive pest control projects are providing safe areas where small numbers of birds are beginning to return. Southland's offshore islands still hold vast numbers of titi where mana whenua have cultural harvesting rights.

Like the haulouts, sea bird burrow ecosystems have high levels of excrement and these colonies play a significant role in cycling nutrients from the rich sea environments on to the land. The loss of birds and mammals from the mainland means our coastal forests no longer receive nutrients from the sea. The long term impact of this loss is unknown but in the same way our garden roses and tomatoes die without regular fertiliser we can expect to see the nutrient hungry species disappearing from our forests.

Haulouts and burrows are hard to view without disturbing their inhabitants, so the best way to explore them is to join a guided trip.

Or you can help protect them by volunteering at a project such as Forest and Bird's Te Rere Reserve, The South Catlins Charitable Trust, Bluff Hill Motupōhue Environment Trust or the Stewart Island Rakiura Community and Environment Trust.

Photo credit: Yvonne Pickford

Frost flats and hollows

During winter, Southlanders get used to waking up to frosty mornings, but some areas of the region get more frequent and harder frosts than elsewhere (especially in hollows where cold air sits and can not readily drain away). When hard frosts become so regular that only the hardiest plants can grow, a frost flat or frost hollow ecosystem is formed. Trees struggle to grow in these environments so smaller shrubs and tussocks take over, creating an inverted tree line. Frost flats can be identified by looking for breaks in the forest along valley floors or on river terraces. In cold weather frost and fog will hang around in these areas longer than in the surrounding forest.

New Zealand is famous for its weird and wonderful birds like the kiwi. But some of our plants are also weird and we have a large number of divaricating shrubs. From a distance these shrubs look like a mass of tangled and interwoven stems, it's often only close up that it is possible to see the leaves and flowers tucked between the stems. No one is really sure why the plants have evolved this way but one theory is that it is an adaptation to harsh environments like frost flats. Cold conditions are a risk to plants because the water contained in cells can freeze creating ice crystals that may burst and killing cells. Growing a lattice of stems around small leaves may provide protection from freezing conditions. A competing theory is that the plants evolved the lattice to reduce browsing by moa. Whatever the reason, divaricating shrubs like weeping matipo (Myrsine divaricata) and bloodwood Coprosma wallii, can often be found in frost flats and hollows.

If you want to see a frost flat up close the walk in to Green Lake hut from the Borland Road or head in to the Takitimus.

Photo credit: Chris Stowe

Red tussock grasslands

The waving red leaves of red tussock are an iconic image in Southland. They are found throughout the region from the coast to the mountains and you can't go on a road trip without seeing a patch on the roadside or snuggled in a gully. But this wasn't always the case. Step back 1000 years and you'd see a region dominated by forest. The red tussock grasslands were probably restricted to wetland margins, frost flats and sub alpine zones. It was only the extensive human induced fires 600 - 800 years ago that created the wide open environments red tussocks need to flourish.

The red tussock grasslands now provide us with important services such as clean water and soil protection. They have been shown to yield more clean water than any other land type. They also provide shelter for lambing and habitat for natural biocontrol agents for pest species such as grass grubs.

The takahe is often held up as one of success stories of New Zealand conservation, once thought extinct a small population was re-found in the Fiordland Murchison Mountains. Numbers are still low but the birds have been brought back from the point of extinction. Red tussock is a key food source for takahe so the takahe breeding enclosures were set up in red tussock grasslands at Burwood. Protection and conservation of this habitat is essential for the continued survival of takahe.

Red tussock grasslands are becoming less common, more fragmented and modified as land development on Southland hill country continues. Our iconic Southland tussockland landscapes are changing.

Where to see: Red tussock scenic reserve Te Anau.

Photo credit: Chris Stowe

Snowbanks

A dusting of snow in the back paddock or a weekend in the ski fields may be the only time most Southlanders get to experience snow, but snowbank communities can be under snow for seven months of the year. Plants living in these chilly ecosystems are right on the edge of the limits for plant growth, they have to cope with cold temperatures and very short growing seasons. Higher up the mountains where snow lies on the ground for even longer are unable to grow at all and plants give way to mosses and lichens.

Despite the harsh growing conditions, in summer snowbanks can look like miniature meadows. These plants have to be highly adapted to this very harsh environment and some are only found in this habitat. The plants make the most of the short summer and produce a profusion of tiny flowers. The flowers attract day flying moths including tiger and ghost moths. Mountain daisies (celmisia) and buttercups (Raunculus) attract pretty picture-winged flies. The aptly named snow grass is one of the most common features of snowbanks, their short stature and hardy nature make them well adapted to the environment. Other plants such as Kelleria form dense cushions that protect them from the winter snows, regular frosts, fierce mountain winds and harsh summer sun.

Hike above the tree line in the Takitimus and Fiordland and you'll find snowbanks. Looks out for shady gully's and southern slopes.

Coastal turf

There is nothing like a brisk walk along the coast to blow away the cobwebs on a fine winter day. But next time you're watching the crashing waves and enjoying the wide open spaces of the coast remember to look down at the ground beneath your feet. On the most exposed rocky cliffs and headlands buffered by salt-laden winds you'll see a miniature jungle. The jungle is created by tiny herbs, grasses and sedges that are so small they look like a well maintained lawn or turf. If you think a lawn that doesn't need mowing sounds like a great idea, you'd be right. Coastal turf plants like Shore cotula (Leptinella dioica and L. monitototo) have been adopted in New Zealand for lawn bowls turf, croquet greens and golf course putting greens.

Despite their size, the turf plants are a diverse and pretty community covered in miniature flowers in spring and summer. It's a special treat is to see the mass flowering of the native gentian in summer.

Historically these turfs were probably grazed by native birds but these birds are now extinct or in such small numbers that the turfs are beginning to be out-competed by taller exotic plants including pasture grasses. The small stature also puts them a risk of damage from hooved animals such as cattle, but in some cases light sheep can be used to replace the grazing birds and keep down exotic weeds.

Coastal turf is worth visiting at any time of the year. They are one of the rarest ecosystems in the country but in Southland they can still be found on the Tihaka Beach Track to Riverton, at Slope Point and Waipapa Point.

If you want to try out a low maintenance lawn you can get turf seeds from specialist suppliers.

Kelp forest

The ocean hides a huge amount of diversity including submarine forests, where seaweed replaces the trees, and fish, jellyfish and crustaceans replace the birds and mammals. The largest and most dominant forest seaweed is giant kelp Macrocystis pyrifera which forms towering pillars from the ocean floor to the surface. The crabs hang on to the kelp like branches of trees, living their lives suspended in the water column. The forests are hunting grounds for New Zealand sea lions that are attracted by the plentiful fish and crabs.

Paterson Inlet has the highest seaweed diversity in New Zealand with 270 species of seaweed and the area has been protected as a marine reserve.

Kelp forests help support our fishing industry by providing a nursery for fish and crayfish. They are also a key food source for kina. In other parts of New Zealand a reduction in predatory fish numbers due to fishing has caused kina numbers to increase above sustainable levels. The large numbers of kina eat the kelp faster than it can grow creating large dead areas called 'kina barrens'.

Kelp forests can protect the land by slowing or dampening storm surges and reducing coastal erosion. They can also capture and store nutrients thereby improving water quality.

Where to see: Ulva Island - Te Wharawhara Marine Reserve

Photo credit: Kelvin Meade

Manuka scrub

Manuka has one of the longest and most prolific flowering seasons. Its white flowers, often tinged with pink, are most obvious during spring but manuka can flower all through winter.

Manuka is found throughout New Zealand and it's one of our most common trees. But not all manuka is the same and experts believe that detailed taxonomic research of Manuka will find that there are several different species including some local and potentially rare endemics.

Manuka is at risk from devastation by myrtle rust a fungal disease that has recently established in New Zealand. The disease attacks plants in the myrtle family which includes manuka. The fungus infects young leaves, shoots, flowers and fruit causing them to deform and die which can prevent the tree from reproducing. Severe infection may also result in tree death. As the disease is new to New Zealand we don't know how well manuka will survive.

Manuka scrub is a 'pioneering' ecosystem because it is one of the first systems to develop after a site has been disturbed through slips, fires or clearance. Its tough pioneering nature and ability to colonise farmland has given it a bad reputation. In the 60's and 70's there were even grants to clear up the manuka to create new farmland. This has left a legacy of thinking that manuka isn't as important as other forest types. But the combination of clearance, myrtle rust and the potential discovery of new species mean that manuka can no longer be considered a secure, common and slight pesky plant. And it's time to reinstate manuka as a national treasure.

Five reasons to love our manuka scrub

1. Honey made from manuka has antibacterial properties making it a highly sought after resource
2. It helps stabilise slips and prevent erosion of hill sides.
3. Manuka is a great nursery crop, it grows quickly and can be used to protect less hardy plants
4. It's ability to flower all year makes it an important food source for birds and insects during the coldest months on the year.
5. Manuka is palatial accommodation for geckos providing safe hiding places and lots of food for some of our most threatened species

Photo credit: Erin Garrick

Flaxlands

When flax is in flower nectar loving birds like tui and bellbirds flock to swamps and wetlands producing a cacophony of singing and the fluttering of wings. The dense tangled vegetation can make them hard to access but getting into their depths can be a rewarding adventure.

Once common across the Southland landscape there are now very few flaxlands left. These densely vegetated wetlands occur on wet but fertile land and as a result have been extensively modified for land development.

They provide a wide range of ecosystem services including water purification, flood protection and carbon sequestration. Flaxlands are traditional mahinga kai areas used by Maori for food collection and for the collection of flax for weaving. Flaxlands also support species of native fish and insects, along with rare birds like the bittern.

Flaxlands to visit

• Castledowns (Dipton) Wetlands (this is a private wetland that is being restored by the Rural Women and Dipton Landcare Group, there is a short track from the road you can use or join the group on a working bee)
• Kakapo Swamp
• Lake Brunton

Braided rivers

Picnicking by the river is a popular activity and the wide, open nature of braided rivers makes them perfect for recreation. The upper reaches provide perfect breeding grounds for trout, and fishing during the summer months can provide a welcome addition to the BBQ.

The 'braided' name comes from the multiple channels the river forms as it winds through a large gravel bed. From above, these rivers look like a woven thread across the landscape. Every year the route of the river will change as the currents move gravel around. During large floods the change can be significant as islands and gravel bars are destroyed or created. The frequent floods restrict the vegetation cover and ability of native plants to survive so the rivers remain stony and open.

The ever changing and mobile nature of these rivers means that they form a mosaic of ecosystems with pockets of vegetation on the most stable areas and open gravels on the newest or most mobile areas. All of these ecosystems are linked and between them they support a diverse range of plants, insects, fish and birds. One of the most conspicuous are the black-billed gulls that nest in large colonies on river islands and forage in surrounding farmland. Unfortunately this visibility belies the health of the population and these gulls are now the most threatened gull species in the world. They are just as threatened as kakapo and are even more threatened than Kiwi!

Look beyond the birds and you'll find a large range of insects and reptiles including the Boulder Copper butterfly and common skinks.

When visiting a braided river, keep clear of breeding birds and watch out for camouflaged chicks and eggs. Make sure you keep dogs on a lead.

Braided rivers to visit:

• Waiau
• Oreti