EcoLincNZ

Category: Species distributions

  • A Knobbly Future?

    A Knobbly Future?

    The Story of the Canterbury Knobbled Weevil

    In 2011, scientists found a mere 26 individuals of Hadramphus tuberculatus, an endemic weevil species, nestled within a small reserve in the tawny high country of Canterbury, New Zealand. This was down from 49 individuals found in 2009. Why was the Canterbury knobbled weevil on the brink of extinction, and where does the population stand now – 14 years down the track?

    Burkes Pass is like a portal – a steep hill that suddenly transforms from the Canterbury Plains of green pastures, forestry blocks and hedgerows into the vast glacial basins, dry riverbeds, tussocks and jewel-like lakes of the Mackenzie Country. The Mackenzie of South Canterbury is beautiful, but also brutal – the sweltering heat of summer paired with the freezing frosts of winter means few people live here.

    On the saddle of Burkes Pass, it was discovered that a long-lost species of weevil did indeed live in this brutal landscape. Called the Canterbury knobbled weevil or Hadramphus tuberculatus, it was scientifically named in 1887, and was found in reasonable numbers, on the then-uncultivated Canterbury Plains. Since then, it has been seldom encountered, particularly after the clearing of its favourite host plant, the Aciphylla – commonly known as the Speargrass plant.

    The weevil was considered extinct, until 2004, when a University of Canterbury student – Laura Young – stumbled across one of these knobbly weevils in a Burkes Pass reserve, rediscovering the species. However, a following study conducted in 2013 found that the species was in decline in Burkes Pass. So, how did they monitor it? How does this weevil survive and what is its future?

    Illustration of Hadramphus tuberculatus, by Des Helmore.
    Illustration of Hadramphus tuberculatus, by Desmond W. Helmore (CC BY 4.0).

    Like the birds of New Zealand, the insects here have evolved without most mammalian predators – with the New Zealand bats being an exception. Many species exhibit traits, such as flightlessness, gigantism, and an inability to self-defend from mammalian predators. The weevil genus Hadramphus is endemic to New Zealand and is a good example of these traits.

    Hadramphus contains four species: H. spinipennis, H. stilbocarpae, H. pittospori and of course the Canterbury knobbled weevil, H. tuberculatus. A common feature amongst all Hadramphus species is their larger size relative to other New Zealand weevils, their flightlessness, and their unfortunate vulnerability to recently introduced mammalian predators.

    The relatives of H. tuberculatus survive in far-flung parts of New Zealand, such as offshore islands and the remotest parts of Fiordland. H. tuberculatus lives in the tussock grasslands of Canterbury, where introduced mammalian predators are much more common. This probably explains the scarcity of the species. The Canterbury knobbled weevil also relies on speargrasses – which are terribly spiky plants but grows impressive flower bunches called inflorescences. Speargrasses were once more common on the lowlands of Canterbury, but have disappeared, due to changes in land use.

    Interestingly, the Canterbury knobbled weevil is one of the few invertebrate species in New Zealand with a legally protected status – under the Wildlife Act. Most invertebrates in New Zealand are considered unprotected.

    A Canterbury Knobbled Weevil adult in hand by Warren Chinn via iNaturalist (CC BY-NC 4.0).

    Because of the apparent threats, entomologists (insect scientists) decided to conduct a survey-based study on the Canterbury knobbled weevil population at Burkes Pass. Through the summers of 2009-2011, pitfall traps were placed out in order to catch these weevils in a small section of a Department of Conservation reserve near Burkes Pass and in adjacent private farmland. This area has large amounts of the golden speargrass (Aciphylla aurea).

    Empty pitfall traps are a type of non-deadly trap to catch insects. They are usually cups placed discreetly in the ground, that unsuspecting terrestrial critters fall into to. The researchers checked these pitfall traps weekly, and a little piece of speargrass was kept in the pitfall trap to feed trapped weevils. Weevils found in a pitfall trap were recorded, measured, and even marked with a unique identification number – in case it was recaptured.

    Unfortunately, the study showed a worrying trend. In 2009, 49 weevils were captured in the pitfall traps, then 41 weevils in 2010 – and then in a drastic drop, 26 weevils were captured in 2011.

    In the 2009 season, a small number of the weevils caught were in the farmland pitfall traps – meaning that they existed beyond the confines of the reserve. But, by 2011, this number of weevils caught in farmland became zero. This might have meant that the reserve was a better place for the weevils, but ultimately they were declining all the same. Many weevils in the reserve were recaptured again and could be re-identified with unique numbers written on their wings! Although the weevils can’t fly, some had been recaptured up to 190 metres away within the reserve – that’s a lot of walking for a flightless insect!

    So, why were the weevils declining? The researchers make no specific discussion on this point, however introduced predators may be the main culprit – particularly rodents. A more recent 2024 study on large-bodied alpine invertebrates in southern New Zealand found that sites with mice had less wētā (a group of cricket-like insects) and these wētā were slightly larger on average when compared with sites without mice. Although wētā have a different ecology to weevils, there could be a similar story going on in the Canterbury high country.

    Since this study, the outlook for the Canterbury knobbled weevil has been grim. Although a ton of work has gone into the Burkes Pass site – including pest-resistant fencing, weed control, and continued searching, there hasn’t been any recent re-discoveries of the weevil here, although bugs have a special talent of hiding in plain sight. Most people are not looking out for funny-looking weevils that live on one of the most hostile plants in New Zealand.

    In a similar circumstance to the 2004 re-discovery, John Evans happened to come across a large weevil on a speargrass near Lake Heron – in the high country of Ashburton Lakes – in 2024. Uploading the observation to iNaturalist, it was quickly confirmed as a Canterbury knobbled weevil by entomologists – revealing a new population of the species. Later searches discovered even more weevils, creating new hope that the species could live on. Despite this amazing discovery, the same conservation issues remain – how can this species be effectively protected for long-term conservation? Perhaps new initiatives for pest control need to be developed – particularly for mice – but this has yet to be established.

    Lake Heron, in the Ashburton high country basin. A new population of Hadramphus tuberculatus was recently discovered nearby. Photo by the author.

    Unlike other species of Hadramphus, the Canterbury knobbled weevil cannot rely on remote offshore islands for survival – as the Canterbury speargrass ecosystems are important for its survival. Mammalian predator control and the protection of the weevil’s host plant should be the priorities.

    Translocation of the species is another option that could be considered, especially given that the weevil did survive in captivity. The Canterbury knobbled weevil could be considered a flagship species for these unique dryland ecosystems in eastern New Zealand, which are often overlooked as important part of New Zealand biodiversity.

    The critical status of this species is a reminder of the enormous loss of biodiversity that has occurred in the Canterbury region. Imagine if knobbled weevils were commonplace on speargrass plants again, living alongside various other native flora and fauna that is facing a similar fate? Losing this species to extinction would be a further loss of what makes this region unique.

    This article was prepared by Master of Science student Noah Fenwick as part of the ECOL608 Research Methods in Ecology course in the Department of Pest-Management and Conservation.

    Links/References

    Bertoia A., Murray T. J., Robertson B. C., Monks J. M. (2024). Introduced mice influence the large-bodied alpine invertebrate community. Biological Invasions 26:3281-3297. https://doi.org/10.1007/s10530-024-03370-x

    Fountain E. D., Wiseman B. H., Cruickshank R. H., & Paterson A. M. (2013). The ecology and conservation of Hadramphus tuberculatus (Pascoe 1877) (Coleoptera: Curculionidae: Molytinae). Journal of Insect Conservation 17:737-745. https://doi.org/10.1007/s10841-013-9557-9

    Department of Conservation (New Zealand) Website (20 December 2024). “New population of critically endangered beetle found”. https://www.doc.govt.nz/news/media-releases/2024-media-releases/new-population-of-critically-endangered-beetle-found/

    New Zealand Legislation. Wildlife Act 1953 (6 May 2022). “Schedule 7: Terrestrial and freshwater invertebrates declared to be animals.” https://www.legislation.govt.nz/act/public/1953/0031/latest/whole.html#DLM278595

    Pawson S. M. (2005). Weevil Upheaval. New Zealand Geographic, Issue 72. https://www.nzgeo.com/stories/weevil-upheaval/

    Young L. M., Marris J. W. M., & Pawson S. M. (2008). Back from extinction: rediscovery of the Canterbury knobbled weevil Hadramphus tuberculatus (Pascoe 1877) (Coleoptera: Curculionidae), with a review of its historical distribution. New Zealand Journal of Zoology 35:323-330.

  • A bounty hunter in the Subantarctic

    A bounty hunter in the Subantarctic

    I’ve been a fan of Star Wars since I was a nine year old being driven to Dunedin to see this new SF film that was supposed to be quite good. There in the Octagon Theatre my young mind was blown by what I saw. We’d never seen anything quite like it. I still can vividly recall the final attack run down the canyon on the Death Star. It was like you were in the cockpit of Luke’s X-Wing.

    Over the last 47 years I have seen most of the Star Wars movies and series. I even didn’t mind the prequel movies. One of my favourite characters was Boba Fett, the bounty hunter. He seemed cool and I liked that he didn’t take off his helmet (I was also about to become a 2000AD Judge Dredd fan, probably for similar reasons). The Mandalorian, featuring more on the galaxy bounty hunters, is one of my favourite Star Wars series.

    Who doesn’t love Grogu? Image by Adrian Paterson

    I’m not sure why I enjoy the SW IP, the stories are reasonably predictable, the names are awkward and clunky, but I guess it is fun, looks good and has some interesting diversity (it’s definitely not all filmed in an abandoned British quarry like most other SF at the time). I particularly liked the islands on Ahch-To where the elderly Luke Skywalker was living as a recluse. Their ruggedness, isolation and ‘bird’ fauna seemed like our NZ Subantarctic islands.

    In the Subantarctic we have our own bounty hunter with the strangely Star Wars-like name of Pacificana cockayni. This spider species, like a Jedi hermit, is only found on the Bounty Islands (a wind-swept collection of small islets) that are very seldom visited by humans. It spends its time hunting among a sparse five other species of spiders and 22 insect species. There are a bunch of seabird species that use the islands for breeding. It’s a harsh place to live and has a precarious food web.

    Pacificana cockayni was first collected by the great botanist, Leonard Cockayne, in 1903. There were a handful of future visits where female adults and juveniles were collected and finally a male was found. When describing a species it is useful to have adults of both sexes (and in spiders differences are exaggerated and easier to find in males). In more recent times molecular approaches, sequencing DNA, allows for a more precise understanding of who your species might be related to.

    Pacificana cockayni. Image by Thomas Mattern.

    Cockayne sent the original samples to a leading British arachnologist of the time with a decidedly non-Star Wars name, but suitably impressive nonetheless, Henry Roughton Hogg (OK maybe a little Star Warsy… I can see an Imperial Star destroyer being commanded by Admiral Roughton Hogg). Hogg decided that Pacificana cockayni was different enough from other spiders to be in its own genus. He then guessed at the family. (“These aren’t the spiders you are looking for.”)

    Over the years other travellers collected a handful of specimens when their journeys brought them to the Bountys. These include the great spider specialist Ray Forster. (“May the Forster be with you‘), one of my first PhD students, Frances Schmechel, and recent masters student, Robin Long.

    Time moves on and we are not in that galaxy far far away now. Many of the spider species lumped together as a big group by Hogg have been moved to more accurate placements by spider specialists over the last century. Cor Vink (Lincoln University), Phil Sirvid (Museum of NZ) and Nadine Duperre (Liebniz Institute) decided to sort out the status of Pacificana cockayni. They could see that things were a mess (“Hogg, you have failed me for the last time“).

    They looked carefully at the various structures of Pacificana cockayni and compared these to the various options for relatives (“Hmmm aren’t you kinda short to be a Miturgidae?”). For example, they found that the stridulatory field on prolateral face of male coxa of leg 1 was different to other closely related species (which to most sounds about as meaningful to the uninitiated as midiclorians).

    Bounty Islands – birds, rocks and a few spiders…. Image by Tui de Roy.

    Vink and colleagues were also able to get DNA from these species as well (or use DNA data that had already been collected). In a recent NZ Journal of Zoology paper they were not able to definitively sort out who the closest relatives of Pacificana cockayni were, but they could show that they had been evolutionary distinct for a long time. Given this distinctiveness and the limited range of this species to the small Bounty Islands archipelago, Pacificana cockayni faces some big problems. “I have a bad feeling about this.“

    The maximum height of the Bountys is 73 m, creating a problem with sea level rise taking away land. Climate change is altering prey patterns for the seabird species that bring guano and carrion back to the islands, and which drives the simple invertebrate food webs. Bird populations are also declining through climate influences and from fisheries. Fewer birds means less food for everyone else that’s stuck on these islands (“It’s a trap!“). And, despite the isolation, there is always the risk of a rodent invasion from a visiting boat. Rodents love munching on large invertebrates.

    Like a rare Jedi knight on the fringes of the galaxy, Pacificana cockayni have faced and triumphed over tough times. Vink and colleagues have allowed us to know just how special this species is and why we should work hard to protect it to give it a fair chance to survive into the future.

    This is the way.

    This article was written by Adrian Paterson (Pest-management and Conservation at Lincoln University). With writing EcoLincNZ articles, do or do not, there is no try.

  • Wild hunters: Unveiling the hidden leopards of northern Pakistan’s borderlands 

    Our adventure begins in the breathtaking north of Pakistan, where the majestic peaks of the Himalayas, and their foothills, stand as one of the last sanctuaries, a place where the sky meets the earth. Here, clouds drift over rough mountains and lush valleys, into dense forests. Glistening lakes and spectacular waterfalls shape this natural paradise.

    In this wilderness, the air echoes to the calls of rhesus monkeys, while wild boars wander through the underbrush. The Himalayan red fox prowls the mountains, on the hunt for colourful pheasants, a tale as old as time. 

    But the fox is not the only hungry predator in these forests. A top predator, larger and stronger, with a powerful bite and covered in unique dots, reigns in the mountainous range. The majestic leopard (Panthera pardus), a mysterious and shy creature, expert at camouflage, is prowling these forests.

    Leopards are amongst the most iconic big cats. Just like other big cats, leopards are endangered. Human activity and landscape alteration pose significant threats to their survival. When leopards and humans cross paths, conflicts arise, turning this top predator from hunter to hunted. 

    Panthera pardus fusca is described as larger subspecies, with brighter
    coloration and smaller rosettes (Bellani, 2019).

    Photo Credit: CC BY 2.0 DEED, taken by Rupal Vaidya in October 2016

    Leopards are generally cryptic and shy, much remains unknown about these ferocious hunters. 

    Muhammad Asad, a PhD student at Lincoln University, started his dangerous journey to this wild region in the north of Pakistan. The dangers of the landscape were not limited to wildlife; humans also posed a significant risk in this troubled region. Undeterred, Asad was ready for the challenge that lay ahead. 

    Leopards are amongst the world’s most widespread carnivores, ranging from Africa to Asia. Prowling over such a vast distribution has led to the recognition of several subspecies, most of which are endangered. The forests in the north of Pakistan are known to be home to leopards, but their subspecies status has not been assessed.  

    Contrary to the legend of water-shy cats, leopards are excellent swimmers. Still, the mighty Indus River was believed to act as a barrier between populations, maybe even keeping subspecies apart.

    To unravel this mystery, Asad and his team collected and analysed tissue samples from leopards. Modern techniques have created a genetic tool as powerful as its name: mitochondrial DNA (mtDNA). Mitochondria, the powerhouses of our cells, have long been known for their role in providing power for our cells. These powerhouses also carry their own DNA, passed down maternally, making mtDNA incredible useful for studying population dynamics and subspecies differentiation.

    A key protein encoded on the mtDNA, NADH 5, is essential for energy production and is highly variable among big cats, making it an excellent candidate gene for subspecies identification.

    Through their research, Asad and his team found two distinct subspecies of leopard in the north of Pakistan, P. p. saxicolor and P. p. fusca, both belonging to the Asian group of leopards.   

    Panthera pardus saxicolor is commonly a bigger subspecies and is often
    more pale coloration, with bigger rosettes (Kiabi et al., 2002).

    Photo Credit: CC BY 2.0 DEED, taken by Guido Konrad in July 2021

    These findings mark the first subspecies identification in this region and hold significant implications for conservation efforts. The coexistence of both subspecies in the same region suggests an interesting natural corridor that connects leopard habitats, offering hope for their conservation in the face of habitat fragmentation.

    At the same time, discovering two subspecies living in the same area opens up the possibility of them interbreeding. This can create some challenges for conservation. We might wonder: could one or both of these subspecies disappear over time? Or will they blend together and create a new subspecies? Hybridisation is very unpredictable, which is why it’s important to work on conserving both subspecies. They each have unique evolutionary histories, which are the product of thousands of years of adaptation and survival, and could potentially be lost due to this phenomenon called hybridisation.

    These findings not only help leopard conservation in the paradise of the Himalayan belt in the north of Pakistan, but also contribute to global conservation efforts to protect this amazing species. By identifying subspecies and unveiling their genetic patterns, we can better protect them. It is important to protect both subspecies, which helps protect the overall species Panthera pardus.

    This article was prepared by Master of International Nature Conservation student Eric Tscherbatko as part of the ECOL608 Research Methods in Ecology course.

    Thank you to all scientist who contributed to these amazing results, namely Muhammad Asad, Francesco Martoni, James G. Ross, Muhammad Waseem, Fakhar I- Abbas and Adrian M. Paterson for your important work!

    Asad M, Martoni F, Ross JG, Waseem M, Abbas F, Paterson AM. 2019. Assessing subspecies status of leopards (Panthera pardus) of northern Pakistan using mitochondrial DNA. PeerJ 7:e7243 https://doi.org/10.7717/peerj.7243

  • Creeks spread invasive herbs in New Zealand

    Invasive plants can have a devastating impact on our natural environment.

    What are invasive plants? Put simply, they are non-native plants that spread rapidly within New Zealand and pose a significant threat to ecosystems, agricultural production, or human health. It sounds awful.It is even worse than it sounds.

    Lodgepole pine (Pinus contorta) CC BY by Chris Schnepf, University of Idaho, Bugwood.org

    Invasive plants pose a threat to natural ecosystems as they are often highly competitive compared to native plants. Invasive species also spread rapidly to take over the living space of native plants, alter ecosystem structures, and reduce biodiversity.

    Many exotic plants are invasive, such as lodgepole pine (Pinus contorta) and Scotch thistle (Cirsium vulgare). Invasive plants change the composition of plant communities and affect food webs and ecosystem balance. For example, the introduction of eucalyptus alters soil chemistry and moisture content, affecting the survival of other plants and animals (Mengistu, 2022).

    Invasive plants also impact agriculture and grazing and can cause massive economic damage. Scotch thistle (Cirsium vulgare) can quickly spread and take over farmland, reducing crop yields. Unpalatable invasive plants can compete with pasture grasses, reducing the area of grassland available for grazing and affecting livestock husbandry (Massey Universy).

    Scotch thistle (Cirsium vulgare) CC BY by John Barkla,  

    Some exotic plants are harmful to human healthy, like Giant Hogweed (Heracleum mantegazzianum),  which can cause third-degree burns and even blindness by simply touching it!

    Knowing how invasive plants spread can help us to control them effectively. A study conducted at Lincoln University in 2013 focused on whether creek habitats are a source of spread for these invasive plants.

    Researchers from Lincoln University (Alice Miller and colleagues) studied Hieracium lepidulum (Asteraceae), an invasive herbaceous plant that has proliferated in the South Island in recent decades. It now occurs in a wide range of upland habitats, from improved short tussock grasslands, to intact beech forests, to alpine herbaceous fields. Hieracium is a more shade-tolerant relative of the widespread pasture hawkeed.

    Historical data suggests that Hieracium is common in naturally disturbed habitats, such as stream edges and forest canopy gaps. Alice selected creek catchments in the area with the longest known history of  H. lepidulum invasion in New Zealand:  Craigieburn Forest Park on the eastern side of the Southern Alps, Canterbury, New Zealand. She surveyed 1,144 spots along 17 creek catchments.

    Giant Hogweed (Heracleum mantegazzianum). CBS News

    Alice and colleagues found that creek habitats (e.g., stream edges and disturbed areas) play an important source role in the dispersal of H. lepidulum. These areas tend to be subject to more natural and human-caused disturbances, which provide a suitable growing environment for  H. lepidulum, and contribute to its rapid reproduction and accumulation in these areas.

    The high resource availability and frequency of disturbance at stream edges allow H. lepidulum to colonise and spread rapidly. Disturbed areas, such as forest clearings and trail edges, provide similarly favourable conditions. Stream habitats provide connected linear dispersal paths that allow H. lepidulum to spread rapidly along streams and from there into neighbouring areas.

    The dispersal patterns of H. lepidulum in forests and subalpine areas were found to differ. In forests, the dense canopy and ground vegetation form a natural barrier to the spread of this plant. As a result, the density of H. lepidulum in forests decreases rapidly with increasing distance from creeks, except in areas with higher light availability, such as tree-fall gaps.

    Forested areas near creek edges remain vulnerable to invasion. In contrast, in subalpine habitats, H. lepidulum density declined more gently with increasing distance from creeks. This suggests that these areas are less restricted to seed dispersal corridors and more susceptible to invasion.

    Location of study area with the 17 surveyed creeks in bold and indicated by an asterisk. From Google Map

    The study also found that multiple environmental variables had an effect on H. lepidulum abundance, with dense canopy cover reducing light and inhibiting its growth. Areas closer to stream mouths were usually more frequently disturbed and H. lepidulum abundance was relatively higher. Higher elevation areas pose a challenge to H. lepidulum growth due to harsher climatic conditions, but the invasion is still significant in subalpine areas. Disturbances, such as human activities, increase the chances of reproduction and dispersal of H. lepidulum.

    Alice provided several recommendations for managing and conserving areas affected by H. lepidulum. First, she suggested prioritising efforts to limit the spread of this invasive plant by reducing disturbances in the environment and using biological control methods. Second, she recommended setting up monitoring systems in vulnerable subalpine habitats to detect and control H. lepidulum early and prevent it from forming large populations. Finally, while disturbances are natural in these ecosystems, it is important for managers to consider the additional impact of human activities, such as building roads and trails, which can exacerbate the invasion, especially in subalpine areas where the barriers to invasion are lower.

    Hieracium lepidulum Stenstr. (Asteraceae).CC BY by John Barkla

    Through this study, we have gained valuable insights into the dispersal patterns and environmental impacts of the invasive plant H. lepidulum. This hardy invader tends to thrive along creek margins and in disturbed areas, making these locations hotspots for its spread. It is our responsibility to protect these pristine landscapes from invasive species.

    If you’re hiking in New Zealand’s stunning mountains, keep an eye out for those little H. lepidulum spreading on the sly. Let’s be the guardians of nature and protect this pristine land from these “little invaders” that are taking over our ecosystem.We can help preserve the natural beauty and biodiversity of New Zealand’s ecosystems, ensuring that these “little invaders” do not take over and disrupt the delicate balance of our environment.

    This article was prepared by Master of Pest Management postgraduate student Hao Zhang as part of the ECOL608 Research Methods in Ecology course.

    References:

    Mengistu, B., Amayu, F., Bekele, W., & Dibaba, Z. (2022). Effects of Eucalyptus species plantations and crop land on selected soil properties. Geology, Ecology, and Landscapes, 6(4), 277-285. https://www.tandfonline.com/doi/full/10.1080/24749508.2020.1833627

    Miller, A. L., Wiser, S. K., Sullivan, J. J., & Duncan, R. P. (2015). Creek habitats as sources for the spread of an invasive herb in a New Zealand mountain landscape. New Zealand Journal of Ecology, 39(1), 71-78. https://www.jstor.org/stable/26198696

    massey.ac.nz/about/colleges-schools-and-institutes/college-of-sciences/our-research/themes-and-research-strengths/plant-science-research/new-zealand-weeds-database/scotch-thistle/

    https://www.cbsnews.com/news/giant-hogweed-plant-causes-blindness-third-degree-burns-discovered-in-virginia-other-states/

  • Jumping to the top of the world: new salticid spider species in the Southern Alps

    Spiders.

    Your reaction to that word might determine whether or not you finish reading this post, but try to bear with me — at least for a little while. While I can accept that most people aren’t nearly as fond of spiders as I am, I think all but the truly arachnophobic (it’s okay; I understand that you can’t help it) can agree that the jumping spiders are among the “cutest” and most acceptable spider groups. These active little hunters can often be found in or around the house, and their big binocular eyes and expressive “face” make them a lot more relatable than your average creepy-crawly. Well, most of them!

    A newly-described female Ourea petroides from the Ōtira River valley, Arthur’s Pass. © own work, 2022. CC-BY-NC.

    Jumping spiders, in the family Salticidae, are among the most well-researched spiders in the world, with over 6,500 species described. Meanwhile, the jumping spiders found in Aotearoa New Zealand – apart from the most commonly-encountered species – are very poorly known to science. There are thought to be around 200 species in NZ, with about 50 known well enough to be named. However, we can only reliably identify fewer than a dozen of them. Compare this with Australia, where hundreds of species are known already, and work to describe the rest is well under way.

    Not to be outdone by the Aussies, Lincoln University’s Robin Long, along with her supervisor Dr Cor Vink, decided to do something about that. For her Master’s project, Robin set out to catalogue and describe the jumping spiders found in some of NZ’s most remote and extreme environments: the rocky heights of the South Island’s alpine zone.

    Robin visited 21 different sites all over the Southern Alps, from Paparoa to Fiordland, collecting 170 jumping spider specimens (all by hand!) from up to 1,800 m above sea level — and logging some impressive hiking mileage in the process!

    Looking across the Ōtira River at a scree slope where Ourea petroides can be found, Arthur’s Pass. © own work, 2022. CC-BY-NC.

    Through DNA analysis and careful examination of microscopic features on each spider, Robin separated those 170 specimens into 12 new species, and determined that the group was so unlike others known to science that it represented a brand new genus (a group of closely-related species with a common ancestor). She named this genus Ourea because, like the ancient Greek mountain gods, many of the species were found to be associated with a specific mountain range.

    Many of NZ’s indigenous species are only found across quite small areas, often because of the (relatively) recent and rapid growth of our mountains — which even today continue to grow taller by around 7 mm per year. Formerly widespread species were split into separate populations by the tectonic uplift, and over the last few million years these now-isolated populations have diverged into new species. Robin’s jumping spiders, much like many other NZ alpine species, took advantage of the ample prey and new habitats created by the growth of these mountain ranges. Over time these spiders even developed cryptic colours and patterns that help to camouflage them against the particular rock types they live amongst.

    Magnificent moustache: a female(!) Ourea saffroclypeus from the Remarkables Range. © Robin Long, 2022. CC-BY-NC.

    Not content with merely describing a whole genus and a dozen new species, Robin also set about studying and describing the spiders’ behaviours when interacting with other members of the same species. Jumping spiders have exceptional eyesight, and are known for communicating with each other through visual displays that range from the bronze hopper’s simple leg-waving, all the way to the flamboyant, colourful dances (which often incorporate vibration as well) performed by the aptly-named peacock spiders.

    The four Ourea species that Robin observed in the lab each exhibited a unique set of behaviours when they met another spider, and these behaviours differed depending upon whether they met a member of the same or the opposite sex. Males postured fiercely at each other, squaring up in a face-to-face grappling contest with legs and fangs outstretched.

    When attempting to impress a female, males gestured with their legs and “zigzag-danced” their way closer, before attempting to reach out and gently stroke the female’s head. Perhaps unsurprisingly, this final move had quite mixed success! Females meeting each other were a bit more sensible, and usually made a few simple (though probably quite impolite) leg gestures at each other, before one or both turned away and went in the opposite direction.

    Despite the enormous amount of work that went into researching these spiders, Robin acknowledges that her almost 150-page thesis has only scratched the surface of the topic. Little is known of the spiders’ life histories or the individual species’ spatial distributions, and it’s “very likely” that there are additional species in the genus waiting to be discovered on other mountain ranges.

    Exquisite camouflage: Ourea petroides, Ōtira River valley, Arthur’s Pass. © own work, 2022. CC-BY-NC.

    Robin also suggests a similar study would likely uncover another distantly-related group of undescribed jumping spiders living quietly in the Southern Alps. This is a common problem with New Zealand’s invertebrate fauna: while we have a good general understanding of what’s around us, there are still huge gaps in our knowledge — and usually the studies that attempt to address this just end up revealing more unanswered questions!

    We have a rich history of brilliant people, like Robin, studying, documenting, and describing New Zealand’s unique invertebrate biodiversity, and there are still many new discoveries to be made in every corner of our little country. But, despite huge technological advances, research has dwindled in recent decades due to funding redirections and the restructuring of government services.

    Under the looming threats of climate change and habitat loss, we need to pay closer attention to the smallest and most enigmatic (if not always particularly cute) creatures that live alongside us, lest they disappear before we even have a chance to study them. Australia is well ahead of NZ in this regard, with funding and support for taxonomic studies provided through their world-leading ABRS scheme. I’m not much of a sports enjoyer, but beating the Aussies at this game is one trans-Tasman rivalry I could definitely get behind.

    This article was prepared by Bachelor of Science (Honours) student Dustin la Mont as part of the ECOL608 Research Methods in Ecology course.

  • Under the southern moss

    In popular media New Zealand is often portrayed as a ‘Lost World’. From Middle-earth to Narnia, from Skull Island to Mythic Greece, New Zealand has often stood in for a director’s idea of a mysterious place that time forgot. This started in the 1960s with In search of the Castaways, a cheesy Disney live action film. I’ve even done this myself in an article on New Zealand’s biological history and how the Lost World might be a useful theme with which to explore why we see such a special biodiversity here.

    A lost world?

    One way to make a place look ancient in a movie is to drape everything in moss. Moss-covered ruins and trees just look old and mysterious. Walking through the New Zealand bush we usually see a lot of moss, especially in the wetter parts of New Zealand. Moss wrapped around branches and in mounds on the ground gives the vibe that the forest has been unchanging and quiet for a long time.

    How accurate is this?

    Wendy Kentjens (with David Glenny from Landcare Research, and Tim Curran and Jon Sullivan from Lincoln University) wanted to find out what determines where moss (or bryophytes as they are technically called) grows. She has published a paper about it in NZ Journal of Botany.

    Her study site was at the Boyle River near Lewis Pass. At the site there are stretches of beech forest as well as manuka/kanuka areas. And there is a lot of moss, on the branches, on the ground, growing high in trees, even around the streams.

    Wendy collected moss samples to identify which species were present. She also looked at lots of environmental factors to see if they created patterns for mosses. She measured things like tree-trunk diameter, canopy cover, ground cover, species of plants, and habitat pH.

    Wendy busily trekked around 98 plots where she found 30 species of moss. There were a lot of differences between habitat types, with the stream areas having very different moss species to everywhere else. Beech forest communities were reasonably different to manuka communities, even though they were in close proximity. More moss was found on the damper and darker south sides of trees.

    And moss can be comfortable for a nap! Image from Adrian Paterson

    There are a lot of mosses growing in our forests. Are they ancient? Many of the areas at the Boyle, particularly the manuka/kanuka forest, are only a few decades old as they are recovering from being made into pasture. So, mosses are able to colonise and grow in these areas very quickly.

    When we look at a moss clad tree or boulder we shouldn’t automatically assume that it has taken centuries to accumulate. These forests are highly changeable systems and moss are just as opportunistic and quick to grow as the surrounding plants.

    Mosses may give off the old lost world vibe but they are as young and vibrant as the next plant or lichen. However, if production companies want to come here to spend lots of money on their next historical/fantastical/science-fictiony epic then I guess we can put up with it.

    Adrian Paterson is a lecturer in Pest-Management and Conservation at Lincoln University. He generally likes moss, and it does make him think of the Lost World!

  • Farming and biodiversity: what’s on 0.5% of Canterbury Plains?

    Imagine the Canterbury Plains blanketed in tall trees interwoven with small hardwoods. This beautiful, unique landscape is then singed into dry grassland with the arrival of Māori. Continue to imagine European settlers introduce weedy exotics that infest the landscapes, once again modifying the region. Now, picture the current landscape – a monotonous cover of dairy farms. Which of these images would you think is best for our native and endemic species?

    Prior to humans or today? (Think from an insect’s perspective)

    The plains have been a dynamic landscape ever since humans stepped foot in our vulnerable country. They will continue to experience dramatic changes in the future with the ever growing population leading to climate change, urban expansion and agriculture intensification.

    The 1940s saw the commencement of irrigation on the plains so that farmers could have a reliable water source to enhance the production of pasture and crops. Water facilitated the development of dairying from sheep farming, into the landscape we see today. Between 2002 and 2012, the Canterbury herd increased by 115%, accounting for 13.5% of the Aotearoa dairy herd.

    These drastic landscape changes have been detrimental to many of our precious native species by creating unfavourable conditions and habitats, species such as the bellbird (Anthornis melanura) have suffered. Some species, such as paradise shelducks (Tadorna variegata), have exploded in population numbers due to the favorable wet conditions caused from irrigating.

    Within the Canterbury Plains, less than 0.5% of this area is still the original remnant forest. Canterbury has been described as the most biological deprived and most modified environment in Aotearoa due to the intensification of agriculture. However, agriculture is a big portion of the country’s economy, bringing in approximately $10.6 billion (5%) of the country’s Gross Domestic Product (GDP).

    The food and fiber sector are major employer, providing jobs to over 359,000 people. Not only does it feed New Zealanders, it is also a big player in the global food market. in order to come to terms with this environmental dilemma, farms need to incorporate more sustainable agricultural practices, to feed the world and to support biodiversity. Currently through education and awareness this is already becoming a point of discussion.

    There has been a push to introduce native vegetation into farming systems. Several studies have examined the impacts of intensive dairy farming on soil health, vegetation, and life below ground. Farmers are now starting to see the benefits of even simple things, such as planting native vegetation. Such plantings not only positively impact farms, but also our are good for our native species, from small bugs to cryptic skinks and chatty birds.

    Mike Bowie from Lincoln University, like me, grew up on a family farm, and went on to tertiary education in ecology. This brings a helpful perspective to topics around the interaction of agriculture and ecology. It led Bowie to check out the biodiversity in the Bankside dryland remnant that is surrounded by an intensive dairy farming landscape. The Bankside Scientific Reserve in a 2.6-hectare area established in 1969. Mike wanted to know how adjacent agricultural land impacts the soil composition and fauna in this reserve area.

    Aerial photograph of the Bankside Scientific Reserve with kānuka and matagouri dotted throughout. (From Bowie et al., 2015)

    In 1970, an initial vegetation survey was conducted by Molloy within the new reserve. Bowie’s survey in 2015 found that only 31% of plants that Molloy surveyed still remained and that 27 new exotic species were present. The fauna found in the remnant were different to that of the neighbouring agricultural land. Bowie discovered the presence of four native earthworm species along with six exotic species. The number of the exotic worm species decreased with distance into the reserve.

    Bowie and his fellow researchers found 112 specimens of invertebrates, including many beetles as well as a significant native species, the ground weta! Soil pH, nitrate, and phosphate levels were all lower in the reserve compared to the surrounding paddocks.

    These observations highlight the need to retain existing dryland remnants and to establish other reserves throughout the plains. A diverse landscape will support a diverse range of species. I think farmers and the community are now starting to see the value of incorporating native vegetation and agroecological principles into their system, such as mixed species pasture systems.

    We don’t all need to put three hectares away into a reserve. Even small steps, such as planting a row of diverse natives along a fence line or waterway, will make a huge difference, if many farms join in.

    One thing that is highlighted in this study is the need for continued maintenance of restoration and remnant projects. It is not a plant and leave situation (no pun was intended…). Weed and pest control should be continually applied in these areas to prevent exotic weeds and animals from becoming established and smothering and displacing the natives.

    An example of this is in practice Te Ara Kakariki group that is establishing green dots (tiny native areas) from the Southern Alps to Lake Ellesmere/Te Waihora on private properties. This increases the connectivity of native planting, further increasing the power that these small areas can make overall. Animals and invertebrates will be able to spread throughout these dots and over the region.

    Farming has transformed the landscape of the Canterbury Plains. Image from Adrian Paterson.

    Farmers are becoming more aware of sustainable principles through education from organisations such as Te Ara Kakariki, DairyNZ, Landcare trust, and councils. Through education, ecology is becoming more interwoven into their practices. It will be a trick balancing the need for feeding the world and protecting the environment. Ecology is an excellent way to find this balance in agriculture, it can be adapted to any farming system to suit their needs and desires.

    Mike wants to help bridge this gap, not only in this study, but also others that he has conducted throughout his time at Lincoln University. Mike has examined how native plantings encourage native and beneficial invertebrates on Canterbury dairy farms, plus many more. I too believe that ecology and agriculture can work together to create a more sustainable agriculture sector that can efficiently produce food and improve food security, whilst supporting the health of the soil, water and biodiversity.

    This article was prepared by Master of Science postgraduate student Sam Fitzgerald as part of her ECOL608 Research Methods in Ecology course.

    Further reading

    Practical guide for landowner and farmers for landcare

    Improving biodiversity – Beef + lamb

  • Detecting eDNA: everything, everywhere all at once

    Let’s say you want to know what animal species are present in a forest. You could walk along line transects and record the species visually observed. You could set up trail cameras to take pictures of passing animals for as long as there is enough space in the memory card and battery life in the cameras. You can use the acoustic survey method to study bats, birds, frogs, and even some monkey species, as they can be distinguished based on their sounds and calls.

    Depending on the size of your study area, making a list of the animal species present might take a several hours to several months because you will need to carry out various methods to identify them, which may also require species experts.

    These are well-established conventional methods for biodiversity monitoring, but is there no single method to find all the species in a given area at once? A one-size-fits-all t-shirt?

    There is a rapidly developing method that can identify a good portion of species in a given study area, including those living on the ground, in the ground, in the water, and even those flying in the air.

    Every organism contains genetic material called deoxyribonucleic acid (DNA), passed down from parents to children. All organisms from the same species have very similar DNA.

    An illustration of the double-helix of the DNA molecule. Original public domain image from Wikimedia Commons

    This technology takes advantage of the traces that organisms leave of their DNA in their environment, whether feathers, skin, scales, urine, or faeces. These traces, known as environmental DNA (eDNA), can be found in soil, water, and air.

    This shiny new method is called DNA metabarcoding. Simply put, it identifies organisms by matching their DNA with reference DNA from the gene database or library. It is like matching the barcode of products when you check out at the supermarket.

    The process begins with collecting water or soil, or even air, samples from the study area. These samples typically contain genetic material from diverse organisms, including bacteria, plants, and animals.

    Once samples are collected from the field, they are brought to the laboratory. DNA is separated from the samples, amplified, and sequenced to generate vast amounts of genetic data that can be compared with existing DNA databases and reference libraries such as GenBank for species identification.

    Environmental DNA – An emerging tool in conservation for monitoring past and present biodiversity – Scientific Figure on ResearchGate. Available from: https://www.researchgate.net/figure/The-overall-workflow-for-environmental-DNA-eDNA-studies-with-examples-of-organisms-that_fig1_269724781 License: CC BY-NC-ND 4.0

    DNA metabarcoding can detect a broad range of organisms at once, providing a snapshot of the species diversity within the study area. That way, you can avoid performing various sampling methods. How convenient is that!

    Of course, no method is perfect, even DNA metabarcoding. Since it is still developing, there are limitations. The public gene library has the DNA references of many species but this is still a small fraction of all the species on earth, so far. There can be contamination in the samples, which could disrupt the results. Errors can occur not only during sample collection in the field but also in the laboratory.

    Compared to DNA metabarcoding, conventional methods have stronger standardised techniques for sampling and for interpreting the datasets. Besides, in the context of biodiversity monitoring, conventional methods can provide detailed information, such as abundance, age, sex ratios, and individual animals’ special characteristics, such as colours and conditions, which DNA metabarcoding cannot tell us.

    Conventional methods are like pictures with tiny pixels portraying good resolution, but their taxonomic scope is limited, whereas those of DNA metabarcoding cover a broad range of species, but the resolution is coarse.

    Is there the best of both worlds?

    Yes! Robert Holdaway and colleagues, including Ian Dickie working at Lincoln University, suggested that combining DNA metabarcoding with conventional monitoring methods will benefit scientists in many ways.

    Using them together will enable scientists to test and improve the reliability and accuracy of our still-developing DNA metabarcoding method. Moreover, combining them will result in a higher chance of detecting species from the same lineage.

    Robert and colleagues provided three case studies in New Zealand that can benefit from the dynamic duo.

    First, the duo can be of advantage to the nationwide measurements of New Zealand’s biodiversity. They can provide greater taxonomic coverage and more thorough information on the relations among biodiversity, ecosystem functions, and services.

    Second, integrating DNA metabarcoding with Māori biodiversity monitoring approaches will bring more understanding to the Māori worldview of interconnections among living and non-living beings. Metabarcoding can enhance biodiversity inventories, identifying species important and relevant to Māori which are rare or hard to find using conventional methods.

    Third, combining DNA metabarcoding with traditional surveillance in detecting pest species at the early stage will secure native species and landscapes from harmful biosecurity threats, such as harmful pests and diseases.

    In addition, DNA results shared from various surveys using the dynamic duo will be added to the reference libraries making them more resourceful and convenient for future research. Having more reference DNA sequences of species in the reference libraries, like GenBank, will make biodiversity monitoring much easier by identifying species with just a few clicks.

    DNA metabarcoding is a rapidly developing and powerful tool for monitoring biodiversity. Integrating it into conventional methods will lead to a stronger method to get plausible results. Overall, as Robert and colleagues indicated, not only will they add value to New Zealand’s biodiversity and Māori culture, but they will also protect the native natural environment and species through early detection of pests.

    This article was prepared by Master of Science postgraduate student Zin Mar Hein as part of the ECOL608 Research Methods in Ecology course.

    Together, they will indeed make the best of both worlds for conservation.

  • Small animals show us the value of old natural forests

    Hambach. You are in Germany right now, halfway between Cologne and the Belgian border. I’d like to warmly welcome you to the Hambach forest – an ancient forest that is dominated by oak and hornbeam, representing a rare forest type in modern Germany. The Hambach forest is the last remnant of a forest that ranged over wide flat plains since the end of the last ice age around 12,000 years ago. Regrettably, it has become famous for being gradually absorbed by a vast hole!

    Tree house in the Hambach forest.
    CC BY-NC 2.0 by Tim Wagner, Flickr

    The Hambach forest used to range over an area of around 5 500 ha. During the past four decades, around 90 percent has already vanished. What remains today is not a normal forest anymore – idyllic, undisturbed, and peaceful. The forest is not only threatened by further sliding into the hole. In 2018, the Hambach forest also became the stage for one of the largest major police operations, owing to another curiosity about the Hambach forest: it is inhabited by people, living in tree houses. Occupying the forest, they want to protect what is left of it and demonstrate against the further expansion of the hole. However, since the forest is privately owned by the company that sacrifices it for the hole, activists were forced out of the forest with the help of police power – before occupying it again.

    So what is the gigantic hole? It is the result of four decades of open-cast coal mining in the Hambach region. However, its further growth will eventually take an end. For the year 2038, Germany has committed itself to complete the coal phase-out, a critical step for Germany’s energy transition. Until then, coal power stations in Germany can be fuelled by coal – extracted from German coal mines (“holes”), with a spectacularly bad impact on the climate. Still, based on the coal-phase out, the remaining part of the Hambach forest can be saved.

    Hambach open-cast coal mining hole.
    CC BY-SA 2.0 by Traveling Tourist, Flickr

    Growing up close to the Hambach forest, that received international attention in the environmental and climate movement, I’ve been concerned about one question for a very long time: How can we replace an ancient forest that is destroyed for mining purposes?

    “If we are moving several villages, people, and a motorway for the open-cast coal mining, why don’t we also move the forest?” That is how people in my region would have addressed this question in the past. Believe me or not, that’s exactly what has been done. At one end of the gigantic hole, the largest artifical hill worldwide was created and recultivated with trees. It serves the region now as a recreation area, comprising an about 70km network of hiking trails. “Forest is forest. There is no difference”, people say in my region. So why be concerned?

    But is it really that easy? Are humans really able to shape a new forest within a few years as a replacement for a destroyed ancient forest, that has the same value for biodiversity and people? And will the planted trees provide an appropriate habitat for all mammals, birds, insects, spiders, herbs, lichens and other important life forms that used to inhabit the lost forest?

    In many countries around the world, there are nowadays regulations regarding compensation and restoration measures that mining and other companies have to fulfil when their activities destroy land. However, in reality, is it always possible to restore an ecosystem that has undergone complete degradation from a natural forest to a mining site, back to its original state and biodiversity value? Otherwise, it is possible to shape a new ecosystem with the same values at another site – like it was aimed with the planted artifical hill as a compensation for the destruction of the Hambach forest? Fortunately, there are ecologists who have learned the answers to these questions. Closely monitoring the process of ecosystem restoration they can tell how successful undertaken restoration efforts are for biodiversity.

    So, now that we’ve already practiced thinking in great dimensions, let’s undertake a great jump to another mined forest – we’re jumping off Germany, over Italy and the Mediterranean Sea, crossing the Arabian Peninsula and the Indian Ocean, passing Australia and are finally landing in… Auckland! Well done! We’re standing here at the Hunua Quarry site, near Papakura in South Auckland. It is part of the Hunua ranges that consist of over 20 000 ha of native forest, comprising tawa, podocarp, kauri–hard beech, and taraire forest as main vegetation types.

    The Hunua Ranges.
    CC BY-NC 2.0 by Neil Hunt, Flickr

    The Hunua Quarry is managed by Winston Aggregates, New Zealand’s largest aggregates provider. As a restoration measure, in six years over 140 000 plants have been planted in this highly modified habitat after quarrying. The aim is to provide a new forest as a replacement of the forest area destroyed. Next to the restoration area, you can still recognize unrestored areas of exotic grassland that have established after quarrying, as well as undisturbed mature native forest.

    Researchers from Lincoln University (Mike Bowie and colleagues) studied the invertebrate communities at Hunua Quarry, including wetas, beetles, cockroaches, crickets, spiders, centipedes, earthworms, ants, flies, mites, moths, slugs and snails, amongst many others. Although rather small animals, invertebrates are essential for the functioning and health of ecosystems, thereby making an important contribution to biodiversity. The objective of their study was to develop a better technique for the assessment of restoration success after mining, using invertebrates as bioindicators. Bioindicators are species that react sensitively to changes in their environment so that they can be used to assess the quality of an ecosystem.

    The researchers collected invertebrates in the undisturbed mature forest, in restored areas, as well as in the unrestored exotic grassland. They compared how many and which invertebrates were living in the respective areas. Interestingly, the undisturbed mature forest, the restored areas, and the unrestored exotic grassland were characterized by very different invertebrate communities. The invertebrates found in the six-year-old restored areas were mostly still very unlike those found in the undisturbed mature forest. For instance, the researchers were able to collect eight times more cave weta in their pitfall traps in the undisturbed mature forest than in the restored areas. In addition to cave wetas, the mature forest also harboured many spiders and beetles. Hence, if the forest restoration process is successful, it is expected that more cave weta, spiders and beetles typical for mature forest will inhabit the restored sites in the next years. At the same time, fewer exotic snails, slugs and earthworms that were found to be characteristic for the unrestored exotic grasslands are expected.

    This beetle,
    Holcaspis mucronata,
    was found most abundant in the mature forest.
    CC BY 4.0 by Birgit E. Rhode, Wikimedia Commons

    The study identified several invertebrate species as bioindicators. These can be used in future studies to assess the success of forest restoration at mine or quarrying sites. The study findings have been recognized in several other invertebrate studies of different parts of the world, for example, in a global synthesis on how good forestry plantations are at providing habitats to native beetles in comparison to natural forests. In that study, restoration sites were considered as forestry plantations, being planted by humans for conservation purposes and therefore different from natural forests. Another study dealt with the effect of removing an invasive plant as a restoration measure on an Mediterranean island. It referred to the study at Hunua Quarry for the use of beetles as bioindicators to observe the effects of restoration.

    All in all, the study showed that invertebrates might tell us more about the quality of a forest than you would easily see yourself. Hence, studying invertebrates as bioindicators has great potential for making better decisions in ecosystem management and for restoration projects. I hope that research about restoration will also raise public awareness for the complexity of biodiversity and the needs for appropriate habitats. Perhaps, I will hear many people around the Hambach forest region in Germany say: “Forest is not like forest. We need to consider old natural forests as valuable habitats and save them from vanishing, not only for the sake of spiders and beetles.”

    This article was prepared by Master of International Nature Conservation student Vivien Michel as part of the ECOL608 Research Methods in Ecology course.

    Link to the research article:

    Bowie M, Stokvis E, Barber K, Marris J, Hodge S. 2018. Identification of potential invertebrate bioindicators of restoration trajectory at a quarry site in Hunua, Auckland, New Zealand. New Zealand Journal of Ecology 43.

    Read more:

    Donahue, Michelle Z. 2018. Is Germany’s Hambach Forest Doomed by Coal? National Geographic, April 13. https://web.archive.org/web/20190914181247/https:/www.nationalgeographic.com/news/2018/04/hambach-forest-germany-logging-coal-conservation-science/

    Coal exit will save Hambach Forest: activists. Deutsche Welle, January 27, 2019. https://www.dw.com/en/german-coal-exit-plan-will-save-hambach-forest-activists-say/a-47251256

  • Defend the buffer!

    “Hold the line! The invasives are coming!”

    “Captain, we’re losing ground! The phosphate is encroaching.”

    “Retreat to higher ground! It’s safer up there.”

    “Send in the spiders and beetles! Earthworms, you stay here.”

    “Defend the Buffer!!!” [insert battle cry]

    If the plants and insects at Bankside Scientific Reserve could talk, they would probably sound something like that. While this 2.6 ha protected area is home to important communities of native species, it is under threat of phosphate intrusion and the breaking-up of the local habitat. Humans have greatly altered the lowland Canterbury Plains of Aotearoa/New Zealand. With the recent switch to irrigated dairy farming, very few patches of undisturbed native dryland vegetation are left in the region. This change in land-use has led to a higher reliance on fertilizers as well as water for irrigation, which has come with its own set of challenges.

    Aggressive introduced weeds, pasture grasses and forbs, have also begun to dramatically alter the functioning of native plant communities. Remnant areas are both vulnerable and essential to maintaining native ecosystems (hence the need to defend the buffer). Mike Bowie and his team investigated one of these remnant areas, looking at soil chemistry, plant distribution, and soil invertebrates along transects at the Bankside Scientific Reserve. Their study identified the current conservation value of the reserve, assessed how persistence of native biodiversity changed along the pasture-reserve gradient, and evaluated the effects of the likely infringement of irrigation water and nutrients from adjacent farmland.

    The vegetation of Bankside Scientific Reserve had been studied previously by Malloy (1970), who provided a detailed catalogue of the flora, listing 66 native vascular plant species. Jenson & Shanks (2005 – unpublished DOC Report) also completed a one-day reassessment of the site, but recorded only 14 native species. Today, the vegetation at the reserve can be described as a patchwork of native woody shrubs, made up mainly of makahikatoa, matagouri, and dry grassland. As Mike and his team point out, the modified soil conditions seem to have made the reserve not as well suited for native species, and better for the invasion by exotic plants. Compared with detailed surveys prior to the dairy conversion, only 31% of the original 65 native vascular plant species were found in the current study, and 27 new exotic species had arrived since the original survey.

    As for the underground conditions, soil nutrient concentrations and pH were lower in the reserve than in the surrounding farmland, with peaks of nitrate and ammonium being recorded at the boundary. Meanwhile, soil phosphate was higher in lower-lying areas within the reserve. Four species of endemic (Megasolecidae) earthworms were found in the reserve, but not in the neighbouring pasture.

    Other cool finds included ground wētā (Hemiandrus sp.) and trap door spider (Cantuaria dendyi). A 2011 survey by Emberson et al. (2011) also found the large rare rove beetle, Hadrotes wakefieldi, and several species of long-horn beetles. As opposed to the earthworms, the diversity and abundance of beetles and spiders in the reserve was similar to that recorded at least 10 m into surrounding farmland.

    Another interesting take-away from this research, is the importance of areas of higher elevation. Although elevational differences between highest and lowest contours were <5 m in the study, the higher areas were very important in avoiding environmental change from agricultural drainage and effluents. They helped to maintain environmental conditions that were closest to the original habitat, providing the best-suited habitat for native plants and animals.

    Image created by Catherine Priemer

    The work of Mike Bowie and his team, along with previous studies, points out the significance of small remnant reserves for the conservation of indigenous invertebrates found in these rare dryland ecosystems. Their findings also suggest that lime and phosphate fertilisers may represent the main threats to dryland nature reserves in irrigated dairy landscapes. Above all, their research underlines the importance of the soil environment in sustaining the variety of plant, animal, and insect life in this unique environment.

    Taking the team’s findings into consideration, the maintenance of a buffer zone – a protected zone established around sensitive or critical areas – could be beneficial in lessening the impacts of human activity and land disturbance around remnants, such as Bankside Scientific Reserve. To do this, native species can be planted between agricultural and conservation areas, to help protect sensitive habitat. The key take-away: Defend the Buffer!

    This article was prepared by Master of International Nature Conservation student Catherine Priemer as part of the ECOL608 Research Methods in Ecology course.