Biodiversity in Nelson
Biodiversity (biological diversity) is the diversity of living things. It encompasses all life on land, in fresh water and in the sea, including the places or ecosystems where plants and animals live.
From the Waimea Inlet to Cape Soucis, the Nelson region has an instantly recognisable, diverse natural environment, which comprises coastal forests, estuaries, dune lands, streams, rivers, as well as the Dun Mountain and the Mineral Belt.
These locations support a rich diversity of plants and animals, some of which are not found anywhere else in the world. For instance, the Nelson green gecko is found nowhere else on the planet but right here in our own backyard, as is the Back Beach beetle, whose precious habitat is the Tahunanui Back Beach.
The Nelson region was once covered in lush titoki, pukatea and native beech trees, and forest giants such as the mighty kahikatea, New Zealand’s tallest tree. Our streams teamed with native fish and eels, and birds of many varieties used them as food-rich corridors between the forested mountains to the coastal flats.
Unfortunately, these ecosystems have degraded through vegetation clearance, infilling and unsustainable use of natural resources. The voracious appetites of pests like possums and the smothering ability of invasive plants like old man’s beard, add to these pressures.
Let’s work together to bring back species like the South Island kokako, the long tailed bat or the whio. If we all take action we can turn the tide on the invaders and bring the wild back into our lives.
Native animals, birds and fish that are special to the Nelson region:
- Nelson green gecko
- Whio / blue duck
- Korimako / Bellbird
- What can we do to help the return of the korimako?
- Long Tailed Bat
- The South Island kokako
- Native Fish in Nelson’s Streams
- Banded rail/moho pererū
- Variable Oyster Catcher
Native plants that are special to the Nelson region:
- Forest Giants
- Beech Forest
- Beech Mast and the threat to our birds
- Beech trees and their place in the eco-system
Nelson green geckotop
Nelson Green Gecko, photo: Rob Tucker
The Nelson green gecko is unique to the Nelson Tasman region, and is found in open scrub land, such as manuka and kanuka forests. It is hardly ever seen, but may be heard as it has an unusually loud barking noise, in fact, the loudest of all the world’s geckos.
Nelson green gecko are born live and usually as twins, with sticky feet allowing them to move almost anywhere. They are active during the day, seeking insects to feed on, but are susceptible to a range of introduced predators such as rats and stoats.
You can help the geckos and skinks by providing habitat in your garden by heaping rocks or providing divaricating shrubs such as Muehlenbeckia species to provide safe cover and to attract insects for food.
If you see a Nelson Green Gecko, take note of what you saw, or take a photo, and let us know!
Whio / blue ducktop
The whio, or blue duck, lives in clean, fast flowing streams in the forested upper catchments of rivers and can occasionally be seen (or heard) if you are fortunate, in the headwaters of the Maitai River tributaries. Because they nest along the riverbanks, they are at high risk of attack from stoats, cats and rats. Whio are rarer than some species of kiwi.
The whio can be identified by their streamlined head shape, thick beak which allows them to scrape insects off rocks, and large webbed feet. They have a distinctive high pitched whistle sound which the males make, and a rattle call made by the females.
Fossil records show that whio were once present throughout New Zealand but are now much less widespread. It is estimated that in the South Island there are under 700 pairs remaining.
Whio require healthy streams within forests with high water quality, low sediment loadings, and a diverse range of insect life to feed on. They are an indicator species for good river health as a population of whio means a healthy, life supporting river system.
If you see whio in the Nelson area, let us know.
The kākā is a large parrot that lives in forested areas and though once common, now occur naturally in only a few localised areas including around Nelson. In part, this is due to the habits of kākā which evolved prior to the introduction of predator species. kākā nesting habits in tree hollows make it extremely vulnerable to rats, stoats and possums as young chicks and mothers are unable to escape. Fortunately, their numbers in the South Island are growing, including in Nelson. kākā have been seen, for instance, in the Marsden Valley Reserve.
A unique bird, the kākā uses its strong beak to open cones and hard seeds, and to help them when climbing trees. Their brush tongue is used to extract nectar from flowers, and their feet are used to hold food and hang from branches to reach fruit.
If you see kaka in the Nelson area, let us know.
Kākā: South Island kākā song (MP3, 2,540K) (opens in new window)
2 minute 41 second recording of South Island kākā song.
Weka are making a return to Nelson and are quickly becoming a source of interest, humour, and in some cases, irritation as their curious character see them invading suburban gardens in search of foods and pilfering of small objects.
The “coo-et” call of the weka can be heard on dusk and the early evening particularly.
In the past, weka was itself a food source for Maori, and later for European settlers, who knew them as “wood hens”. Their up close and personal behaviour, and the fact they do not fly, made them an easy catch.
They are now a protected species.
Weka are at threat from stoats, but also from cats and dogs. Their presence in urban environments can also make them victims of road kills, snail and slug baits, and also of pest control operations
where their inquisitive nature can sometimes see them caught in the traps set to protect them.
Because the weka are scavengers, their interactions with humans can be problematic. They are, however, a part of our natural heritage and we can live alongside them more harmoniously by not encouraging them to take food from houses by feeding them.
They may also pull new vegetables out of freshly planted gardens as they are fond of newly dug soil, so try tilling and planting a few days apart.
Western weka song (MP3, 651K) (opens in new window)
41 second recording of adult Western weka song.
Korimako / Bellbirdtop
Imagine walking in the early Nelson morning, and the trees along our streams and in our parks are literally vibrating with the sound of the beautiful korimako / bellbird.
Once common in our native forests, this small and precious bird is under threat from introduced predators and the loss of habitat. If you visit some of our parks such as the Marsden Valley Reserve or the Grampians,
you can still hear the curious and melodious bellbird, but how wonderful would it be to see more of them right here in town.
Bellbirds are recognised for their song which was described by Captain Cook as being like “small bells exquisitely tuned”.
Their song is flashier than their appearance, with subtle shades of green meaning they are easily camouflaged in the forest environment, but can give themselves away with their rapid and characteristic flight patterns.
What can we do to help the return of the korimako?top
In native forest, korimako/bellbirds live in areas of diverse and dense vegetation, but in more modified environments they will live and feed amongst eucalyptus or willows. We can plant in our gardens and reserves some of those foods that bellbirds love such as kowhai, flax, or kaikomako – the bellbird tree.
In your own garden you can try offering sugar water for both bellbirds and tui, though the tui are likely to be the winner in that competition!
As bellbirds are under threat from introduced predators, you can trap in your own backyard, or join a trapping group. Bellbirds breed in Spring to Summer, and mate with the same partner every year in the same territory.
Long Tailed Battop
D'Urville Long-tailed Bat. Photo: Brian Lloyd
Long tailed bats were once common, but are increasingly scarce or at risk of completely disappearing. But they do live right here in Nelson, for instance in the Maitai Caves area where it is believed the same little bats travel from the Pelorous region.
The bats are tiny creatures that look like very small birds as they fly at dusk seeking insects to feed on. They can fly over a range of around 100 km!
Bat calls are at a very low frequency which can be heard using a bat detector and can only be heard by some people.
Bat numbers are in decline due to clearance of lowland forest habitats, particularly some of the older trees, and predators such as cats, rats, stoats, and possums.
Forest and Bird is undertaking a Bat Recovery Programme. Find out what is happening to help the Bats and how you can be involved.
The South Island kokakotop
The South Island kokako is sometimes referred to by its other name: the Grey Ghost.
South Island kokako once lived in beech forests and low scrublands above the tree line, from northwest Nelson to Fiordland but their numbers rapidly declined after the introduction of cats, rats and stoats and by the late 1800s were already rare.
The kokako is a member of the same family as the extinct huia and the threated saddleback. It is part of New Zealand's oldest bird family, which is thought to have evolved about 30 million years ago.
The South Island kokako was declared extinct by the Department of Conservation in 2008, but this status was moved to “data deficient” in 2013 following a credible sighting in Reefton - 46 years after the last accepted sighting!
Kokako are an elusive bird, and whether or not the South Island kokako still survives is a mystery. Kokako mimic other birds, or even the sound of animals like goats or deer. There is only one known photograph of a live kokako.
There have been purported sightings of the South Island kokako around Nelson, including in Cable Bay, so keep your eyes and ears open while out in the field, and if you think you see a kokako, note down everything you see, or better still, take a photograph!
How to identify a South Island Kokako?
The South Island kokako is a large bird, blue grey in colour, with a black mask, and two orange fleshy wattles at the base of its curved black bill. They hop from branch to branch and on the forest floor, and glide when they fly. The haunting sound of a kokako is a slow kuk-kuk sound, much like the sound of their name kokako.
To report a suspected sighting, go to: http://www.southislandkokako.org/
Native Fish in Nelson’s Streamstop
Nelson’s urban streams, even including piped culverts, are home to a variety of native fish, some of which are nationally threatened or in decline.
From time to time, the streams are surveyed for fish life, and in one such survey, a 100 metre of Poorman’s Valley Stream alone revealed 16 different species living in it!
The rarest of these species is theshortjaw kōkopu, a habitat sensitive species that is found only in New Zealand, with only one ever recorded in Nelson.
Other species identified in our urban streams are similarly in decline. The Giant kÅkopu, of which only two have been recorded in Nelson, can grow up to half a metre in length and live for 25 years or more.
Banded Kokopu. Photo: Martin Rutledge DOC
Some native fish such as inanga and banded kōkopu are among the species that make up the group of fish called galaxiids (because of the resemblance their skin has to a galaxy of stars). Most of us know them as whitebait.
With such a diversity and number of species already living in our streams, it is important that we protect this taonga and ensure that while it isn’t possible to return our waterways into the forested streams they once were, we provide them with the best urban habitat possible.
Why do the creatures living in our urban streams have such a hard time surviving? Waterways are no longer the clean and shady places they once were: water becomes heated without shade, there is less insect life to feed on, and there are fewer places to seek refuge. Then, as the fish try and make their way up the streams, they are blocked by barriers such as dams and culverts. There are things that you can do to help these unique little creatures survive.
- All outside drains lead directly to the nearest stream or the sea. Prevent anything other than rain going into stormwater drains – even seemingly harmless or “eco-friendly” products will harm aquatic life.
- Fence margins of streams to prevent stock from trampling banks and defecating into freshwater.
- Plant stream edges to enhance habitat. Native grasses and shady native trees are ideal.
- Avoid walking – either yourself or your dog – in the long grasses alongside water edges where fish are spawning as eggs remain out of water for several weeks. In popular spots, signs will indicate inanga spawning sites to remind you to avoid trampling on stream edges.
- Never dump rubbish, including green waste, into streams. This not only contaminates the stream, but is the prime source of environmental weeds invading our wider environments.
- If whitebaiting, stick to the fishing regulations and keep your catch small.
- Consider setting up or joining a community stream care group that can be involved in protecting and enhancing a stretch of your local stream.
Fernbird / Mātātā
The fernbird, or the mātātā as it is known in Maori, is small bird of wetland habitats that can still be found in parts of Nelson including at Paremata Flats.
The fernbird is difficult to see as they are secretive in their ways, and are well camouflaged amongst the dense vegetation in which they live. Fernbirds are poor fliers, but do fly short distances staying close to vegetation. They can be heard with their distinctive sound, often in a duet between pairs.
The South Island fernbird is at risk with an estimate of only 1500 pairs remaining nationally. This is due in large part to past land practices of draining wetlands so that these habitats are seriously depleted. In addition, introduced predators including cats, rats, dogs and stoats are a continuing threat, with entire populations having been wiped out by rats on some islands. Protection and enhancement of wetlands throughout the country is critical in assisting in the survival of this little known bird.
Pictured: Fernberd in Totaranui. Photo: Clint Fern
Banded rail/moho pererūtop
Banded rail / moho pererū
The banded rail / moho pererū is an uncommon native species that is at risk in New Zealand, but can be found right here in the Nelson Tasman Region, living in the salt marshes of the Waimea Inlet.
About the size of a domestic chicken, the banded rail is hard to spot as it is well camouflaged and shy in its behaviour. Their brown upper parts, and finely banded black and white under parts, allow it to blend with wetland vegetation.
The banded rail is threatened as a result of loss of habitat and introduced predators. Before the arrival of Europeans the birds were abundant but the draining of vast areas of wetlands to support settlement and farming (over 90% of this ecosystem is lost), has destroyed most of the habitat of the banded rail.
Predators such as cats, dogs, stoats and rats predate on banded rail. You can learn more about what is being done to protect the banded rail here:
Variable Oyster Catchertop
The variable oyster catcher is found only in New Zealand where it lives and breeds along our sandy shorelines feeding on coastal invertebrates, such as crabs and snails.
Variable oyster catchers are recognised by their black upper parts, and underparts that can range from black through all shades of grey, or to white and can be heard with their loud piping noises when warning of danger.
Variable oyster catchers are at risk from introduced predators and loss of habitat. You can help this characterful bird by being a responsible pet owner while at the beach, or by assisting in trapping programmes which target pest species such as stoats and rats.
The Nelson region was once covered in forests of many different types of trees, but the largest of these were what are known as “Podocarps” – trees which go back to the time when New Zealand was part of the super continent of Gondwana and include those we now call rimu, kahikatea, miro, mataÄ« and tÅtara.
These ancient trees are much depleted in their numbers due to land clearance but examples can still be seen locally, such as the giant kahikatea on track named after it in the Grampians Reserve and the many matai and miro growing in the upper Maitai Valley.
Because podocarp forests tend to grow in lowland areas with rich soils, these are the very same soils much sought after by early farmers and European settlers, who felled the giant trees for many uses, or simply burned the forests and drained the soils for farms and settlements.
Podocarps are a member of the conifer family and reproduce using cones, but cones that look more like berries. The word podocarp means “fleshy foot”.
The seed of Podocarp trees are enjoyed by many of our native birds, who spread the seeds which sustain the forest growth. Some of these trees such as Miro have very large seed, which can only be eaten by our native wood pigeon, the Kereru, which is why Kereru are so critical to the survival of our giant forest trees.
There are a number of threats to these mighty trees including possums which do extensive damage to the forest, weed species which suppress regeneration, and the demise of bird species which spread the seeds of these trees. The forest is regenerating though despite these threats, and a walk in one of Nelsons forested reserves will enable the careful observer to not only admire the larger trees, but also notice the valiant seedlings which push their way through the carpeted floor below.
Beech Forests for the largest areas of indigenous forest type in New Zealand, and can be seen in our forested reserves such as the Marsden Valley and Matai Catchment. The reason for their better rate of survival, is that Beech trees tend to grown in higher altitudes that were not sought for agricultural or settlement purposes. About 2 million hectares of land in New Zealand is still covered exclusively by Beech forest.
There are five different species of beech in New Zealand which grow at different altitudes and in different soil types:
- Hard Beech (Fuscospora truncata) and black beech (Fuscospora solandri) are found in the lowland areas of the North Island and northern South Island.
- Red beech (Fuscospora fusca) prefers the foothills and inland river valley floors particularly where soils are fertile and well drained.
- Silver beech (Lophozonia menziesii) prefers higher, wetter conditions.
- Mountain beech (Fuscospora cliffortioides) grows in the mountains and on less fertile soils than silver beech, often forming the tree line at high altitudes.
Beech Mast and the threat to our birdstop
You may have heard about what is known as the “Beech Mast” which is when there is a particularly large number of seeds produced. At these times, Beech trees can produce millions of seeds – up to 250 kg of seeds per hectare. When this happens, the numbers of rats, mice and stoats rapidly grow as there is a lot for them to eat but once the seeds are all gone, and the numbers of pests have increased, they turn to our native birds for food. This is why a mast year is considered to be such a threat to our native bird species.
Beech trees and their place in the eco-systemtop
The beeches are important for supporting the survival of our native mistletoe as three of these species grow on beech trees. The Crimson Mistletoe grows almost exclusively on Silver Beech, the Red Mistletoe grows on black, mountain and silver beech, and yellow mistletoe grows on mountain and black beech. All these species are threatened due to possum browsing.
Beech trees also have a mutually beneficial relationship with a group of fungi, known as mycorrhizae. The fungi lives in the tree roots and take sugars from the tree and in return, the tree absorbs minerals which the fungi provide from the surrounding soil.
Native beech scale insects that play an important part in the chain of life in our forests as food for other insects and birds. The scale insect lives in beech bark and excretes honeydew. This honey dew is important as an energy source to bellbirds, tui, kaka, lizards and honeybees, though unfortunately is also a great attractor to wasps which can make beech forests an uncomfortable place to be in the Autumn months!
Did you know that there are 8 different types of kowhai that have originated in New Zealand and no-where else in the world? Like most of our native plants, kowhai have adapted to our environment and have been both loved and used by all people who have settled here.
Kowhai is valued by Maori for its medicinal properties as well as its hard wood durability, and is valued by everyone for its beauty. Native birds including tui, bellbird, kaka and kereru all feed off the nectar, leaves or flowers.
Some types of kowhai are what are known as “divaricating” plants which is a unique feature of some of our native shrubs and low growing trees. This means that the branches are dense and interlaced making a “tangled” effect. One theory for why some of our plants grow this way, is that it protected them from browsing by Moa, a less evocative reason is that it is an adaptation to a dry, windy or frosty climate.
Kowhai will germinate easily from seeds if you wish to try to grow your own trees, but the hard seed coat needs to be scratched to reveal the yellow colour within to allow germination to happen. Try careful scratching with sandpaper and the seed will quickly grow into a small seedling, and eventually a beautiful tree!