Category: biodiversity

The odd-shaped claw… is alone no more

I think most of us at some point in our lives experience loneliness. Even we as a species are alone, having separated from our closest relatives, chimps, several million years ago. We are also alone in our genus with the last of our Homo siblings species having gone extinct roughly 10 – 40 thousand years ago. Now, there is only us, Homo sapiens.

For the Gradungulidae family of New Zealand’s spiders shared the same story until recently.

Gradungulidae, the large clawed or odd-clawed spiders, is a family of spiders endemic to New Zealand and Australia. Gradungulids are identified by their asymmetrically large claws on the 1st and 2nd legs that they use to capture prey(giving rise to their ‘odd-clawed’ name).

Until recently there were only three species of Gradungulidae found in New Zealand; Gradungula sorenseni, Pianoa isolata, and Spelungula cavernicola.

Granungula sorenseni, Forster, 1955. Photo: Sebastian Doak.
Photo taken 18 August 2021, sourced from Wikimedia Commons. Cc-by-4.0 license.
https://commons.wikimedia.org/wiki/File:Gradungula_sorenseni_-_Sebastian_Doak_-_151718791.jpeg

Gradungula sorenseni has the widest distribution across NZ, in forests stretching from Nelson and Marlborough in the north, to western Southland and across the Foveaux Strait into Stewart Island in the south.

Pianoa isolata is found only within the native beech (Nothofagaceae) forest of Waikaia Forest in central north Southland, where it gets its common name Piano Flat spider, named for a series of flats along the Waikaia River.

Piano Flat spider, Pianoa isolata, Forster, 1987. Photo: Steve Kerr.
Photo taken 11 February 2014, sourced from Wikimedia Commons. Cc-by-4.0 license.
https://commons.wikimedia.org/wiki/File:Piano-flat-spider-steve-kerr-cc-by-01.jpg

Spelungula cavernicola, has a more limited distribution, and is one of only two legally protected spiders, the other being the Katipo spider (Latrodectus katipo). Spelungula cavernicola is found, as its name implies, primarily in caverns or cave systems. It is present in the Oparara cave system north of Karamea on the upper west coast of the South Island, caves along the Heaphy River, and in the Motupipi cave region of Golden Bay.

One of New Zealand’s two legally protected spiders, the Nelson Cave Spider, Spelungula cavernicola, Forster, 1987. Photo: Mark Anderson.
Photo taken 15 July 2017, sourced from Wikimedia Commons. Cc-by-4.0 license.
https://commons.wikimedia.org/wiki/File:P1150023-001.jpg

All of these species of New Zealand’s Gradungulids were described by New Zealand’s most accomplished arachnologist, Dr Ray Forster. While describing these species Dr Forster suspected that the actual diversity of the Gradungulids was much greater but he could not gather sufficient samples to captures this within his lifetime.

This extra diversity has continued amongst New Zealand’s subsequent arachnologists. Over the last 20 years Gradungulids specimens have been diligently collected across their distributions to fill this gap within Grandungulid taxonomy (including The following people collected specimens over 20 years: Peter Michalik , Cor Vink , Martin Ramírez , Danilo Harms and Stephen Pawson).

In 2015 a photo was uploaded by Andy MacDonald to iNaturalist of an unidentified species of Pianoa found in Mount Richmond Forest Park, Marlborough. This site is 600 km away from the known population of Pianoa isolata in Waikaia Forest! This find led to the discovery of another population of a different Pianoa species near Rarangi, Marlborough by Patrick Miller. Both of these discoveries were made by amateur naturalists, making this an amazing win for citizen science!

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Unidentified Pianoa sp. (sp. means an unidentified species in the Pianoa genus) in Mount Richmond Forest Park. Photo: Andy MacDonald.
Photo taken 17 October 2015, sourced from INaturalist. Creative Commons copyright. https://www.inaturalist.org/observations/2148126

All of this research and specimen collection over the last 20 years has resulted in the discovery of two new species of Gradungulidae, with there likely being more!

Specimens from Spelungula, Pianoa, and Gradungula were analysed using both DNA and traditional taxonomic methods and confirmed that there was enough difference in populations of Pianoa, and Gradungula to constitute different species!

These two new species have been named Gradungula kahurangi sp. nov. (sp. nov. means new species) and Pianoa civis sp. nov. There are also likely to be another species of Pianoa and another two species of Gradungula, but these were unable to be confirmed due to a lack of adult specimens (where species differences are most obvious).

The populations of Spelungula cavernicola found in the Oparara and Takaka cave systems were not found to be different enough to be two separate species, despite these two cave systems not being connected and roughly 70 km apart!

Piano civis, sp. nov. male raised from a subadult by Cor Vink for taxonomic description.
Photo: John Marris. Obtained with permission from John Marris and Cor Vink for use in this blog.

This suggests that historically, and even currently, there may be travel of Spelungula cavernicola between cave systems, likely using the isolated caves of the Heaphy Valley. This is a rather impressive feat for a cave spider!

This lines up with present research on Spelungula cavernicola being troglophiles (species that can live both in cave, but also on the surface) rather than troglobites (species that live exclusively in the permanent darkness of underground habitats, such as caves).

Pianoa isolata, and Gradungula sorenseni now have new siblings, likely with more on the way! However, Spelungula cavernicola is still alone, an impressive testament to their ability to travel outside their cave systems which they depend on!

Diversity of New Zealand Gradungulids appears to be concentrated in the northern part of the South Island. Research is ongoing, with potentially three more species to be described. Citizen science has played a crucial part in the discovery of these new species! So, get out there and get involved.

Who knows there may be a new species out there waiting for you to find it!

This blog was created by BSc (honours) student Max Singers as part of an assignment for ECOL608 and was based on the 2025 paper “Alone no more—Integrative taxonomy of New Zealand odd‐clawed spiders challenges the monotypy of Pianoa and Gradungula ( Araneae: Gradungulidae )” published in Systematic Ecology.

September 24, 2026
Could spiders be our crop protectors?

We are currently living in the sixth mass extinction event. Human activities are driving a global reduction of species and a rapid loss of natural biodiversity. One of the significant contributors to this crisis is the intensification of agriculture, as farmers have resorted to chemical inputs to increase their yields. This approach is not environmentally or economically sustainable, with one million species facing extinction in the coming decade.

But hope is far from lost. In order to combat this decline, there is a growing transition to Integrated Pest Management (IPM). IPM applies a strategic approach to pest control, integrating knowledge of plant-pest interactions and a combination of biological, cultural, and chemical methods.

IPM enables natural ecosystems to function alongside, or within, productive food systems. Recent research suggests that spiders could play a key role in IPM, acting as a natural defence against pests in horticulture systems, reducing the need to rely on harmful chemicals.

Spider feasting on its prey (ABCDee David, CC BY-NC 2.0, 2023)

Since the end of World War II, the area of land used for agriculture has plateaued, yet the global population has continued to increase. In order to support the growing demand for food, agricultural systems have utilised chemical inputs, such as fertilisers, pesticides, and herbicides, to increase yields. But this efficiency has come at a cost.

“Crop Spraying – Harvington” (by Mike Finn CC BY 2.0)

Pesticides are different types of poison applied in agriculture and horticulture to treat pests, diseases, and weeds. Their application is not, typically, exclusive to a target, resulting in unintended harm to other species. The use of pesticides to increase efficiency has come at the expense of declining species and biodiversity, as well as our own health as humans.

Despite the associated negative impacts, maintaining a productive agriculture and horticulture industry is critical for national food security, ensuring a reliable food supply to sustain the health and wellbeing of the population. In Aotearoa New Zealand, we are reliant on domestic production, for approximately 99% of our fresh vegetable supply, due to the perishable nature of vegetables and our distance from export markets.

Horticulture also supports our economic well-being through significant export earnings, contributing $6.85 billion for the 2025 export season.

The use of pesticides in food production has the potential to poison our food (by DES Daughter, CC BY-NC-SA 2.0)

How, then, do we ensure the success of our horticulture industry without jeopardising natural ecosystems and biodiversity?

The answer to this question may be hidden in our childhood favourites. From the treacherous Shelob residing in the mountains near Mordor (Lord of the Rings), to Aragog and his kin haunting Hogwarts from the Forbidden Forest (Harry Potter), or the talented weaver Arachne embedded in Greek mythology. What all these characters have in common is: (1) they are spiders, and (2) they are infamous villains. Spiders have a reputation for being an enemy. This perception may actually be their greatest advantage.

A team from Lincoln University and Plant and Food Research recently published a paper in the New Zealand Journal of Ecology (June 2025), reviewing the current literature available, on the use of spiders in pest management in Aotearoa New Zealand. The lead author, Nicola Sullivan, told Radio New Zealand (RNZ) that “Spiders are the most diverse and most abundant generalist predators in horticultural systems that have been seen overseas.”

“Aragog” from Harry Potter (by Dellboyy Art, CC BY-NC-SA 2.0)

International research shows that spiders, as per their reputation, are great natural predators against pests in horticulture systems. Spiders are generalist predators, preying on a range of species at different levels of the food chain and across all stages of life. Spiders are versatile, and able to live in a range of different environments. In order to capture prey spiders, deploy diverse hunting strategies, often killing prey in excess, capturing non-target species, or wounding prey.

These traits increase the effectiveness of spiders in pest management by reducing the number of pests in the ecosystem that eat and damage crops.

The world’s population of spiders, weighs 25 million tonnes, and are collectively responsible for hunting and eating between 400–800 million tonnes of insects annually. To put this into perspective, that is the equivalent of spiders eating the weight of 80–160 million elephants annually.

The spiders’large appetite shows the potential benefits that they could provide if harnessed for pest management. In addition to being great predators, they are also an important food source to other predators, helping to support a thriving ecosystem.

So, is the ancient proverb correct, is the enemy of my enemy my friend? Sadly, this question remains largely unanswered in New Zealand, with only eight studies focused on spiders in agroecosystems. None of these eight focus on the opportunities that spiders can provide for ecosystem functioning. This highlights a significant gap in our knowledge and the need for research in this critical subject area.

“Spider” (by sama093, CC BY-NC 2.0)

A few of the many benefits that spiders can provide in agroecosystems are demonstrated by the research of Hooks et al. (2003), who reported an 89% reduction in plant damage, and Zhang (1992), who successfully used spiders to control aphid populations.

We must move fast to protect the endangered species, ecosystems, and the health of consumers. Future research should first look at understanding which species are present in New Zealand horticultural systems and in what quantities.

This foundation would enable further research into how effective spiders are as a biological control agent, what factors influence their control effectiveness, whether they reduce the need for chemical inputs, and how their presence impacts other species in the ecosystem?

Today, I leave you to ponder if maybe spiders are not the villains we perceive them to be. Is it possible that the perseverance shown by the Incy Wincy Spider is exactly what the horticulture industry needs to protect our declining biodiversity?

This blog was prepared by Brehana Venimore, a Master of Bioprotection student at Lincoln University, as part of an assignment for ECOL608 Research Methods in Ecology.

Paper Reference: Sullivan, N. J., Stringer, L. D., Black, A., & Vink, C. (2025). Harnessing spider biodiversity for sustainable horticulture: A call for research and conservation in Aotearoa New Zealand. New Zealand Journal of Ecology, 49(1), 3600. https://doi.org/10.20417/nzjecol.49.3600

September 16, 2026
A fiery topic: shining light on the acacia understorey

The story of the understorey

New Zealand is home to thousands of native plant species, of which a whopping 80% of these trees, flowering plants and, ferns are endemic – found only in Aotearoa and nowhere else!

A thousand years ago the forests of NZ were comprised of only natives. Since then exotic plants have made their way here – crossing the great seas on waka and sailing ships and riding the air in jets to beautify the human gardens of tomorrow. Sometimes these exotics do more than beautifying modern gardens, they expand and conquer, alongside the human colonists.

Plant invasions pose one of the most large-scale threats to the conservation of biodiversity worldwide. This issue is only getting worse with climate issues allowing for more habitats and niches to be exploited by plant invaders that were previously unavailable.

Acacia is a plant genus that is notorious for enacting the invade and conquer regime, often considered a problematic and invasive weed, with wanted posters in multiple regions of the world. Acacia are also well known by their street name: wattles.

Figure 1. Photo of Acacia dealbata. Image from Donald Holbern (CC-BY-SA-2.0)

But why is acacia considered an invasive weed?

Wattle is a grade-A problem maker, changing ecosystem structures and soiling the soil. It achieves these feats by changing the composition of the forest, altering the variety of species present in the forest and changing the microbiome of the soil (all the little bacteria and microscopic life we can’t see with the human eye). It also likes to participate in, and encourage, arson for its own benefit.

You can read more about how acacia messes with ecosystems and soils soil here:

Ecosystems -> https://repositorio.uchile.cl/bitstream/handle/2250/154809/art04.pdf?sequence=3
(Disclaimer – Requires translation from Spanish unable to provide pre-translated copy)

Soiled soils -> https://doi.org/10.1371/journal.pone.0086560

Acacia and fire

So, why does acacia love fire so much?

As Acacia benefits from fire. Wattles are light loving, early successional plants. They survive after fires through regeneration from seed. This means that after a fire, when there is lots of available light, the Acacia species is one of the first woody plants to start growing and can dominate the scene.

The Acacia genus is also a major fire hazard due to its leaf litter and twig structure increasing the flammability of the fuel giving the genus a moderate/high flammability. This means they catch fire relatively quickly and are able to sustain it as well.

This flammability creates a lovely little loop of increasing fire risk – fire burns acacia, acacia seedlings profit from the fire that opens up the canopy and grows like crazy, Acacia then dominate, increasing risk of fire once more.

Wildfires are an increasing risk as climate issues intensify, making wildfire management a more pressing topic. So, if we think of wildfire management in forests in New Zealand, we could expect that forests with high proportions of acacia to be at a high risk for wildfire.

Figure 2. Illustration of Acacia melanoxylon by Rosa Fiveash

The burning question

So, will Acacia remain present once it’s entered a forest scene, especially if its dominant there? Will it keep coming back, continuing to invade and conquer the forest?

Well…

Some scientists from Lincoln University (Tim Curran, Jon Sullivan and Azhar Alam) wanted to know exactly that. Heading off to investigate the story of the understorey of an wattle dominated forest.

The hot and heavy science:

The study was done in sunny Picton, Marlborough, in a forest found in Picton Bay. The forest was a mixture of native and exotic woody plants where the Acacia species were the most common.

Tim, Jon and Azhar devised 24 random 10×10 m plots that were about 3 km apart. These plots had two main acacia species invaders: Acacia dealbata and Acacia melanoxylon, with A. dealbata being the main invader and common canopy species in these plots. The plots were sampled by measuring the abundance of each species present in different height categories:

<0.3m, 0.3-2m, 2-5m, 5-12m, 12-25m.

To measure flammability, 70 cm offcuts were abducted from 8 mature and healthy acacia trees between the two species in the plots and sealed in black plastic bags and chilled.

Offcuts were then subjected to burning where their flammability was measured in four categories:

Ignitability: How many of the samples ignited per species,
Combustibility: The max temperature reached during burning,
Sustainability: How long the offcut burnt for after the source of the fire was removed,
Consumability: How much burnt after the flame stopped.

Figure 3. Demonstration of the plant BBQ being used to measure flammability (Video by Fire Emergency NZ | YouTube)

You can read more detailed versions of the methods and stats-> https://doi.org/10.1016/j.foreco.2023.121671

Methods for flammability -> https://doi.org/10.1071/WF15047

What was hot:

So, what did they find? How does a forest respond when it’s dominated by acacia? Do Acacia species continue to invade and conquer or…
Enter the underdogs of the acacia forest: the NATIVES!

The study found that in an Acacia dominated forest where disturbances, like landslides and fires, were not common that the Acacia seedlings did not survive beneath their own canopy. Instead the understorey was populated and dominated by native forest species! But why?

Well, the Acacia species is a light loving genus of plant, sunbathing is a favorite hobby. When there is a forest with a dense canopy you get shade. Shade is something that the Acacia species do not cope with.

But what does cope with shade you ask?

Well, none other than NZ natives of courses.

That doesn’t mean that Acacia species were absent in the understorey. The Acacia species dominated the height category of <0.3 m, making up most of the seedlings present. Native plant species dominated every other height category.

If the forest environment was to remain undisturbed then the next generation of forest species would be dominated by NZ native plants. The abundance of Acacia would also slowly decline over time.

This is great as we regain native forest. Another win is that a majority of Aotearoa’s native plants, such as broadleaf (Griselinia littoralis), have low flammability, meaning that they don’t catch fire very easily. Overall, this would likely lower the forest’s wildfire risk – YAY.

However, that is the future. For now, the forest still has an increased fire risk. Acacia dealbata was the 5th most flammable plant species in the plot and the most dominant.

A single fire could still change the entire game, causing a great forest reset due to this high flammability from the presence of the Acacia species. This is also a long-term risk as once A. dealbata is present in an ecosystem they tend to persist, even under native canopies.

_{“This is fine” meme, edited in imgflip by the author}

All it would take is a fire, or another large-scale disturbance, for the Acacia species to dominate once more, due to the existing canopy being cleared and the light-loving Acacia seedlings skyrocketing up to form the new canopy. Like a good villain, they can always come back.

The author, Kayley Wiffen, is a postgraduate student in the Postgraduate Diploma of Applied Science at Te Whare Wānaka o Aoraki Lincoln University. This article was written as an assessment for ECOL 608 Research Methods in Ecology.

Paper Reference: Alam, M. A., Curran, T. J., & Sullivan, J. J. (2024). Variation in understorey floristic composition regeneration and fire hazard under Acacia invaded forest canopy in New Zealand. Forest Ecology and Management, 554, Article 121671. https://doi.org/10.1016/j.foreco.2023.121671

September 15, 2026
The pines are invading! Planting non-native species increases re-invasion

Soil is life

I’m not sure if you’re aware, as I was not aware of this before coming to Lincoln University, but soil is very much alive. There are millions of organisms in a single handful of soil. These critters perform the majority of the ecosystem services provided by soils.

In New Zealand, these organisms range from burrowing animals, to soil-dwelling invertebrates, to fungi, to microscopic bacteria and much more. So next time you walk on soil, think about how much life is beneath your feet.

For plants, a major component of successful growth and survivability is the soil microbiota, such as bacteria, fungi, viruses, nematodes (tiny worms), and many more. I have much love for fungi in the soil microbiota, especially mycorrhizal fungi that are essential for plant growth.

Mycorrhizal fungi form mutualistic relationships (beneficial for both organisms) with plant roots. The fungi extend their network to increase the nutrient intake in exchange for carbohydrates that the fungi cannot produce itself.

There are two major types of mycorrhizal fungi, ectomycorrhizal fungi, which infect the outside of plant roots, and arbuscular mycorrhizal fungi (AMF or endomycorrhizal), which infect the inside of plant roots.

I did a project on ectomycorrhizal fungi abundance on red beech tree roots for SCIE393 where I took this photo of an ectomycorrhizal fungal fruiting body (mushroom) under the microscope (which I thought was very cool). This is really where my love for mycorrhizal fungi started to blossom.

Ectomycorrhizal fruiting body under the microscope – Photo by Lucas Watkin (CC-BY-NC)

Exotic plants are strong invaders

That’s enough about me for now, time to talk about invasions from non-native plants. As I’m sure everyone who lives in New Zealand is aware, we live in an invaded country, full of exotic predators, pests, and weeds.

While everyone tends to think of the worst invaders are pests like possums and mustelids, the worst invaders are actually the weeds. Approximately half of all the vascular plants in the wild in New Zealand are non-native. There are around 25,000 exotic plant species that have been introduced to New Zealand, with around 2,700 of these becoming wild. Compared to around 2,500 native plants, this is an insane numbers of exotic plants and so to conserve our native species, we must do something about all of these exotic species.

From grassland to pineland: The rapid invasion of black pine into well grazed high country pasture – Photo by Jon Sullivan (CC BY-NC 2.0)

One of the worst exotic plant species are wilding pines, such as lodgepole pine and radiata pine. Lodgepole pine was introduced into New Zealand in 1880 to combat erosion. Burning of forests, overgrazing, and introduced browsers, such as deer, goats and rabbits, were clearing the hillsides of our native plants, leading to more slips. The New Zealand government decided to plant exotic plants, specifically Douglas-fir and lodgepole pine to cover the hillsides and reduce erosion.

These pines did stop the erosion, however, what was not anticipated was the enormous dispersal ability of these wilding pines. Seeds of wilding pines can survive for a decade in their cones, grow roughly anywhere, and can travel kilometers from their parent. There is now roughly 800,000 hectares of wilding exotics in the South Island alone, two thirds of which is lodgepole pine!

Wilding pines of Flock Hill Station: The very many wilding pines coming out from the experimental forestry plots in adjacent Craigieburn Forest Park – Photo by Jon Sullivan (CC BY-NC 2.0)

Be careful what you plant!

This paper headed by Joanna Green has contributions from my lovely thesis supervisor Lauren Waller. In it they describe the effects of planting non-native plants on the soil microbiota, and how that can impact what grows there afterwards. They were specifically looking at how well lodgepole pines grow in soils that have been used and conditioned by exotic plant species.

Joanna and Lauren started by using soils that had already been conditioned by 19 native and 20 exotic plant species from another two experiments by Warwick Allen and Lauren Waller. The soil microbiota, the nutrients in the soil, and other factors, like the pH of the soil, had been changed to best suit the plant that had been grown in that soil.

An example of part of the soil microbiota that was conditioned were the ectomycorrhizal fungi. These fungi are required for successful growth by some of our native species, such as our beech, mānuka, and kānuka species. However, exotic species use different species of ectomycorrhizal fungi than our native species. Therefore, when exotic species are grown in soil they will grow well with their species of ectomycorrhiza.

Basically, think of it like this. If you owned a garden and really liked roses, you would grow a lot of roses. You might grow some other plants but the focus of the garden would be on roses. Now, if someone else came in and took over the garden for themselves, they might not like roses as much but might really like petunias. They will then plant petunias in place of where the roses used to be, altering the state of that garden.

In terms of ectomycorrhiza, they require associations to survive, so the native ectomycorrhiza species that were in the soil will die after their native plant partners are gone. Exotic ectomycorrhiza species associated with exotic plant species will then survive. Due to this, it will become a lot more difficult for our native species to grow back in that soil due to a lack of ectomycorrhiza that they can grow with. Conversely, it will be a lot easier for exotic plant species to grow in partnership with a large number of exotic ectomycorrhiza.

Anyway, back to the paper. The researchers found that lodgepole pine grew better in soils that had been conditioned by exotic species, such as black alder, cocks-foot, spear thistle, gorse, and many more. And this was regardless of whether pines had been planted there or not! Lodgepole pine will have a much easier time establishing and invading into areas that have previously had exotic species growing there.

Lodgepole pine tree near Lake Benmore – Photo by abcdefgewing (CC-BY-NC)

So why does this matter?

To conserve our native plants, sometimes we must plant them in areas that have previously grown exotic species. Joanna and Lauren’s research shows that the soil will be conditioned to favour growth of exotic species, and so growing native plants will be more difficult. It will also be a lot easier for exotic species, such as lodgepole pine, to re-invade and take over the conservation site. Therefore, conservation managers must be aware of this soil legacy and decisions must be made in order to manage this re-invasion potential.

So, next time you want to plant an exotic plant, think about the soil, and whether you would rather plant a native instead.

This article was prepared by postgraduate student Lucas Watkin, Master of Science in Conservation and Ecology, for an assignment in ECOL608 Research Methods in Ecology.

Green, J. L., Waller, L. P., Allen, W. J., Orwin, K. H., Pelser, P. B., Smaill, S., & Dickie, I. A. (2025). Plant-soil feedback from non-native communities increases pine invasion and re-invasion potential. Plant Soil, 514(2), 2461-2474. https://doi.org/10.1007/s11104-025-07528-x

Featured image: Did somebody order pines? The rapid invasion of black pine into well grazed high country pasture – Photo by Jon Sullivan (CC BY-NC 2.0)

August 31, 2026
If friend-shaped, why not friend?

It’s a fair question.

If an animal looks soft, furry, and, let’s be honest, kind of adorable… why wouldn’t we treat it like a friend? Picture a common brush-tailed possum, fluffy and wide-eyed, or a spiky little hedgehog snuffling through the undergrowth, both undeniably friend-shaped. They don’t exactly look like villains. In fact, they look like animals we might want to protect.

But here’s the uncomfortable truth: in Aotearoa/New Zealand, these “friend-shaped” animals are responsible for some of the most devastating environmental damage across the country.

A curious little hedgehog (Erinaceus europaeus). It doesn’t look dangerous, but they are surprisingly harmful predators.
Copyright CC BY-SA 3.0, by Tony Willis, from Wikimedia Commons

Early in my veterinary career, I realised just how complicated it can be to care about the environment. I’d signed up to help animals, not to think about how their populations should be controlled. But here in Aotearoa, even the cutest animals can be a big environmental problem.

The scale of the problem means pest management is essential. Conservationists must find a balance between the effectiveness of pest control techniques and animal welfare. This article explores how emerging technologies may help meet this challenge.

Cute… but catastrophic

Aotearoa’s wildlife is unique because it evolved for millions of years without land mammals. The only land mammals native to Aotearoa are, in fact, two species of bats. This isolation means many native birds nest on the ground, can’t fly well, and have limited natural defences against mammalian predators.

When humans arrived, they brought mammals, like hedgehogs, rats, stoats, and possums, with them. This is when everything changed. A stoat might seem sweet and harmless, but it will kill more than it needs. Possums, while wide-eyed and cuddly, can change the types of trees in native forests.

The stoat (Mustela erminea) is an adorable but efficient killer.
Copyright CC BY-SA, 2.0 by Soumyajit Nandy, from Wikimedia Commons

Introduced mammals have had a significant impact, contributing to widespread loss of biodiversity (variety of animals and plants) across Aotearoa. They have had a hand to play in the extinction of many native bird species and continue to threaten many more.

So, while these mammals might look adorable and harmless, their impact is anything but. It’s not that these animals are bad, they’re just in the wrong place.

Why we can’t just leave them alone

It’s tempting to think, “can’t we just let nature take its course?” The problem is, this isn’t how nature originally worked here. These species were suddenly introduced by humans, and native birds didn’t have time to adjust. So the decline in bird species isn’t natural, it’s our fault, and without intervention, many more native species will be lost.

The huia (Heteralocha acutirostris). A bird now extinct, lost in part to predation by introduced mammal predators.
Copyright public domain (CC0-style, no known copyright restrictions in place), by Johannes Keulemans, from Wikimedia Commons

This is why pest control is necessary. It’s not because we don’t like these animals, but rather we are trying to protect something even more vulnerable and important to Aotearoa’s history.

The challenges of traditional methods

Traditionally, pest control has relied on traps and toxins. While these methods are effective, they are not without their downsides. They can be costly, need regular checking and resetting, and pests often return quickly once control efforts stop.

These methods have been under scrutiny for several reasons. One concern is how humane these methods are. Animal welfare remains an important consideration even when trying to reduce or eliminate pest populations. There are also concerns about their environmental impact, including whether the toxins are retained in the soil and waterways. In addition, is the risk of harm to non-target animals, including native birds and other wildlife not intended to be affected.

Traditional DOC 200 trap. Using traditional traps requires substantial staff time, meaning that ongoing funding is needed to maintain them.
Copyright CC BY-SA 4.0, by Kimberley Collins, from Wikimedia Commons

Looking for better solutions

The good news is that things are changing in some really exciting ways! A 2014 study by Dr Helen Blackie and her team reviewed a range of emerging technologies and research for long-term mammalian pest management, several of which are discussed below. The team brought together scientists, university researchers, commercial pest management organisations and iwi (indigenous Māori tribal groups) who worked collaboratively to design new tools that are more humane, better targeted to specific pest species, and more effective over long timeframes.

Helen and her team develop new toxins to minimise animal distress. Some are even based on natural toxins derived from native plants, blending science with mātauranga Māori (traditional knowledge).

Highly poisonous Tutu plant (Coriaria arborea) has been investigated as a potential source of new toxins.
Copyright CC BY-SA 3.0 by Rudolph89, from Wikimedia Commons

Another innovation presented in the study is “set and forget” traps. While these devices have existed for some time. Newer versions use artificial intelligence (AI) to ensure only target pest species activate them. Once installed, these traps can remain in place for long periods without the need for frequent checks or bait replacement, a big advantage over traditional traps.

Smart trap that uses AI to target pest species while avoiding non-target species.
Photograph by Dr Helen Blackie, used with permission.

In the study, the group also helped develop traps that utilise new toxins in a clever way. When the specific pest interacts with the trap, a small dose of toxin is placed onto its coat. The animal then ingests it through grooming, reducing the risk of environmental contamination.

In addition, the group is learning more about pest behaviour, specifically how animals move, feed, and interact at different population numbers. This helps determine the best places for traps, increasing the likelihood that pests will interact with them.

People power in action

As this study has shown, pest control isn’t just about technology. It’s about how people work together to protect the environment. In Aotearoa, pest control programmes rely on collaboration between iwi, conservation groups, and scientists. Each group brings different expertise to the work, from scientific knowledge to local and cultural understanding.

When I discussed the new innovations with Dr Helen Blackie, she highlighted that some of the most successful pest control initiatives come from community-led groups. She emphasised that even though these groups may have fewer resources than larger programmes, they are still often highly effective. They work closely together with a strong commitment, enabling them to share ideas and adapt their approaches as needed. At the end of the day, pest control only works if people are willing to take part!

So…why not friend?

It’s okay to think these introduced mammals are cute, and the instinct to care about all animals is a good one. But, in Aotearoa, protecting native birds and plants requires managing introduced mammals. Not because they’re bad, not because they don’t deserve compassion, but because the balance has already been tipped, and without action, the consequences could be irreversible.

With better tools, smarter strategies, and more collaboration, we’re moving toward a future where pest control is more effective, more humane, and more sustainable.

And maybe that’s the real answer to the question, “if friend-shaped, why not friend?” Because sometimes, protecting one part of nature means making hard choices about another.

Tough decisions need to be made in order to protect tiny native birds like the titipounamu (Acanthisitta chloris).
Copyright CC BY-SA 4.0 by Melissa Boardman, from Wikimedia Commons

How can you help?

Looking after our environment is a shared effort, the more each of us does, the bigger the impact we can make. If you’re keen to take it further, organisations like Predator Free 2050, Department of Conservation, and Forest & Bird offer opportunities to get involved right across the country. Tools like Trap.NZ can also help you protect your own backyard and track your impact. Karawhiua!

Written by veterinarian and animal lover, Kim Telford, a student at Te Whare Wānaka o Aoraki/Lincoln University. Inspired by a curiosity for how humans and animals intersect, as part of the ECOL 608 Research Methods in Ecology course.

Explore the science: Blackie H, M., MacKay J.W., Allen W.J., Smith D.H., Barrett B., Whyte B.I., Murphy E.C., Ross J., Shapiro L., Ogilvie S., Sam S., MacMorran D., Inder S., Eason C.T. (2014) Innovative developments for long-term mammalian pest control. Pest Management Science, 70(3), 345-51. doi: 10.1002/ps.3627.

August 25, 2026
Polka dots, patches and pinstripes? Productive pasture patterns

Do I need to apologise for the overly alliterative title? The excessive use of P’s aside, this title is still ridiculous, who has seen a polka dot pasture? Or a pinstripey paddock? They sound like a figment of Dr. Seuss’ imagination!

But they’re not, it’s science – an ingenious recipe, mixing landscape design, with a pinch of ecology, and a tablespoon of agriculture. Let’s get cooking!

When did we (and by we I mean the human race/ Homo sapiens/ mankind/ womankind/ humanity/ Earthlings), when did we decide that livestock grazing pastures were to be squares of fenced grass? It was probably somewhere around 12,000 years ago when we stopped being nomadic and started agricultural farming.

Fenced grass pastures work, they have been working for thousands of years. But times they are a’changing (insert a “back in my day…” quote here). The human population (no more we’s, it’s getting serious now) has swelled into the billions (8,286,120,266 at the time of writing), requiring massive agricultural landscape expansion to sustain us.

There is no better example of this than where I live; the Canterbury Plains of Aotearoa New Zealand. Less than 0.5% of Canterbury Plains’ native bushland has survived the ever-expanding agricultural and residential landscapes. This is where we run into our big pinch of ecology – if we were to put the native plants and animals back, where would they go?

The answer – into polka dots, patches and pinstripes.

I’ll explain what the patterns are about, as I know you’ve been waiting patiently. They are landscape design patterns of native woody plants within an agricultural livestock pastural setting. They are the answer – cohabitation of native habitats and productive farming, all within one landscape.

Lincoln University‘s multi-disciplinary researchers, James Eggers, Shannon Davis, Crile Doscher and Pablo Gregorini, are the large brains behind this pioneering conceptual design. In their study, they list ideal native woody plant species that can be used to both enhance livestock welfare and restore bush habitats for native birds.

Now we’re cooking with renewable energy, and we’re baking three cakes in one pan – through increasing foraging opportunities for livestock, providing shade and shelter for these livestock, and establishing native bird sanctuaries. Wow!

Picture this – you’re a farmer and this is your Canterbury Plains farm. Nice, right! You have multiple grass paddocks where you graze sheep and cattle. In reality, this is Lincoln University’s Ashley Dene Farm which was used as a case study for this research, but in this virtual Blog, it’s yours.

Figure 1: Aerial view of Ashley Dene Farm Image © 2023 by J. Eggers et. al. Licensee MDPI, Basel, Switzerland. CC-BY 4.0

Let’s say you want to increase foraging opportunities for your livestock. You know that foraging woody vegetation has long been recognised as beneficial. Woody vegetation tolerates poor soils and weather conditions. It provides a range of nutrients and medicinal properties for optimal livestock health. Also, a diversity of forage enhances livestock consumption and can lengthen the grazing season. Finally, foraging allows livestock to exhibit natural browsing behaviour, thereby boosting welfare.

Lucky for you, thanks to this research, we have a list of optimal foraging native shrubs and small trees (shorter plants for livestock access) selected for palatability, tolerance for browsing and growth rate. Now for the fun part – how to arrange these plants. We have three patterns…

Polka dots (or patches): vary in size and are placed within pastures. The central area is fenced to prevent overgrazing and to accommodate natural seedling regeneration.

Figure 2: Polkadots. Image © 2023 by J. Eggers et. al. Licensee MDPI, Basel, Switzerland. CC-BY 4.0

Spreading: balances access to forage, preventing over browsing through the use of a central fenced off strip. It preserves maximal grazing pasture by running along pre-existing fence lines. Livestock can be moved between paddocks/sides of the spreading forage to allow for regeneration on one side whilst the other is browsed.

Figure 3: Spreading. Image © 2023 by J. Eggers et. al. Licensee MDPI, Basel, Switzerland. CC-BY 4.0

Pinstripes (or just stripes): maximises foraging opportunities and is compatible with farming that uses large machinery. The stripes are within a single paddock, placed 40 m apart for optimal browsing, and temporary fencing is used to designate/restrict feeding areas.

Figure 4: Stripes. Image © 2023 by J. Eggers et. al. Licensee MDPI, Basel, Switzerland. CC-BY 4.0

Back to your hypothetical farm, you now have an amazing amount of native forage for your livestock. However, with your farm being on the Canterbury Plains, it is constantly hounded by northeasterly, hot northwesterly, and cold southwesterly winds. Your animals need shelter. Shade and shelter for livestock reduces heat/cold stress, excess moisture loss, improves animal wellbeing, increases feed intake and lamb survival rate.

Here is a native solution with multiple benefits, no more English hedgerows that provide little to no food for wildlife. Native trees and dense shrubs are selected for their height, shade, canopy, and provision of shelter. Unlike the foraging designs, these shelter patterns are fully fenced off to allow for optimal plant growth without the pressure of grazing.

Straight shelter: a pretty straight-forward design (see what I did there) providing shelter in areas of limited space.

Figure 5: Straight shelter. Image © 2023 by J. Eggers et. al. Licensee MDPI, Basel, Switzerland. CC-BY 4.0

Meandering shelter: similar to the straight design, however, with a greater width to act as a wildlife corridor and habitat.

Figure 6: Meandering shelter. Image © 2023 by J. Eggers et. al. Licensee MDPI, Basel, Switzerland. CC-BY 4.0

In-paddock shade trees: taller trees are placed through paddocks, in groups or individually, to provide shade. There is no underplanting to allow for a cooling breeze.

Figure 7: In-paddock shade trees. Image © 2023 by J. Eggers et. al. Licensee MDPI, Basel, Switzerland. CC-BY 4.0

Ah, that’s nice. Now your sheep and cattle are well fed and comfortable. The productive capacity of your farm is in order. But, you also care deeply about native wildlife and want to do everything you can to protect them (but not with a loss of productivity for your farm). Is this possible? Well, let’s see…

James and his team designed native bird bush habitats around a wetland corridor, an area of pre-existing mature trees, and a densely planted area. Densely planting native bushland are better at dealing with edge effects, reducing the distance that light and sound pollution can travel into the patch, and increasing bushland’s suitability for sensitive birds (like kererū). The mature trees act as nurse species for the native seedlings and the wetlands will breed waterborne insects – an additional snack for many bird species.

Whilst the forage and shelter plantings were determined by the needs and landscape of the farm, placement of bush habitats required consideration of the wider landscape. Preference was given to the native bird habitat locations as they had specific requirements. Native bird habitats must connect to a wider established ecological network for birds to be able to travel to the site (within 5-25km distance dependent on the bird species). Amazingly, native bird abundance can almost quadruple with the addition of restored bushland to agricultural landscapes. This research identified ultimate native plants that provide bird food sources and nesting sites.

Figure 8: A comparison of your farm with and without native woody vegetation additions in a combination of design patterns for livestock forage, shade and shelter and native bird bush habitats. Image © 2023 by J. Eggers et. al. Licensee MDPI, Basel, Switzerland. CC-BY 4.0

So now you have an ideal farm! It balances livestock productivity and native bird habitats through adding an abundance and variety of native plants (an increase of 30% woody vegetation in the case study farm). And yes, there may be a reduction in the grazing land area, but, this is offset by increased forage vegetation, combined with fallen organic matter improving soil health and productivity. The addition of native bird habitats will likely have little impact on farming operations.

Forage patterns can be integrated into shelter patterns to maximise land use for grazing. Likewise, forage plantings can be placed next to bush habitats to create multifunctional areas. Shelter and forage plantings can complement the bush habitats, by acting as wildlife corridors, edge habitats, and increase plant species diversity. Your imagination is the limit when it comes to combining and implementing the design patterns, however, site specifications, soil types, climate conditions, livestock density, paddock use, and wildlife reserve proximity need to be considered… so maybe your imagination isn’t the limit, as every farming landscape has different specifications.

We are achieving an agricultural ecological landscape in one location, with broader ecosystem benefits. Restoring and integrating native habitats into farming practice can encourage others to follow, and together we can support the revival of native birds to our currently fragmented landscape. This research kneads together two strong cultural identities of Aotearoa New Zealand – its rich farming history and outstanding natural biodiversity – fortifying and concentrating both.

As these Patches, Polka dots, and Pinstripes do sound like a Dr. Seuss story, it is only appropriate to end with,

“Unless someone like you cares a whole awful lot,

nothing is going to get better.

It’s not.” – Dr. Seuss’ The Lorax

So thanks to all of you reading this, farmers or not, I know that you care a whole awful lot.

This article was prepared by Klara Royster, Master of International Nature Conservation student, for an assignment in ECOL608 Research Methods in Ecology.

Reference Research Journal Article: Eggers, J., Davis, S., Doscher, C., Gregorini, P. (2023). Enhancing Multifunctionality in Agricultural Landscapes with Native Woody Vegetation. Sustainability Journal, 15, 11295.

August 11, 2026
The shrubland invasion: What’s driving it?

Plant communities dominated by mānuka/kāhikatoa (Leptospermum species)or kānuka (Kunzea species) are an extremely common feature of New Zealand’s native biodiversity. They are found in all manner of shapes, sizes, and habitats – dry and wet, high and low, warm and cold. We’ll call these communities ‘shrublands‘ throughout this text. Reality is much more complex with other types of native shrublands made up of different plant species as well as kānuka and mānuka also forming forests or scrub. There’s a great piece here if you want some more details.

If you’ve ever bashed through young, dense, mānuka/kānuka shrublands whilst out tramping you might have noticed they aren’t very diverse. That’s because during this young phase they form such a thick canopy and dense shade that other plants find it difficult to establish. Once these stands age the canopy opens up and lets light in allowing other species to take off.

The weed Spanish heath (Erica lusitanica), the lighter yellow-brown plants near the ground, invading gaps in mānuka (Leptospermum scoparium var. scoparium) shrubland on Bealey Spur. Photo Will Todhunter

These shrublands are important for our native biodiversity. Some are remnants from before humans arrived. Others have expanded following human induced forest clearance and subsequent regeneration. These regenerating shrublands are what we call seral, an intermediate stage in ecological succession.

Succession occurs when an intact ecosystem is disturbed and doesn’t immediately go back to its final climax vegetation. Instead subsequent vegetation communities gradually replace one another until a climax, or stable, state is reached. Under the right set of conditions kānuka and mānuka can shade out introduced grass species and support a transition of landscapes back to native forest.

Banks Peninsula has many classic examples of this phenomenon, and if you go for a walk up Bowenvale Valley, in Christchurch, you should be able to spot large areas of planted kānuka where Christchurch City Council is trying to jumpstart this process.

Including these shrubland species, Aotearoa has a grand total of 2,522 native vascular plant species. This total is far outnumbered by the staggering amount of introduced plant species, with at least 24,744.

In many cases introduced plants can establish in the wild and invade natural ecosystems, including native shrublands. We will call these invasive introduced species weeds. These exotic weeds can negatively impact our biodiversity, displacing native plants and changing the ways our ecosystems function. Weed invasion has been well studied in forest and grassland ecosystems in New Zealand, but less so in shrublands. It is important to understand what drives weeds to invade shrublands, as this can help guide us when considering actions to protect these habitats.

Laureline Rossignaud and Philip Hulme are researchers from Lincoln University who focus their research efforts on biological invasions, including weeds. They looked at information from 247 monitoring plots placed within shrublands across the country to better understand weed invasion into these habitats. Many studies have already investigated whether the number of native plant species in an ecosystem is related to weed invasions, but few studies have also considered the influence of climate, landscape features and the structure of the plant community in question. So, when this pair dived deeper into this topic, what did they find?

Both the number of different species (species richness) and the size of the area covered by a species (its cover) play a role, but they don’t always align. Some shrublands had high numbers of species with low cover, whilst others had low numbers of exotic species but these were high in cover. This second example can be seen when a few aggressive weeds dominate.

Shrubland on Banks Peninsula. Photo by Will Todhunter CC BY

Low species richness, high species cover. The above image captures this, showing vegetation in a mature kānuka stand on Banks Peninsula. An open canopy of kānuka sits above a lower tier of native saplings of māhoe (Melicytus ramiflorus subsp. ramiflorus), poroporo (Solanum laciniatum) and kawakawa (Piper excelsum subsp. excelsum), and a dense ground cover of the highly invasive exotic veldt grass (Ehrharta erecta). The veldt grass forms such dense mats that it limits the establishment of most other plants and was once voted NZ’s worst weed!

A clear takeaway from the study was that the physical structure of shrublands plays a big role in determining how susceptible they are to exotic plants. Shrublands with dense canopies and multiple layers of vegetation act like a shield, limiting open ground and leaving less space for weeds. Shrublands with open areas let in more sunlight and have more available options for weeds to gain a foothold.

The surrounding land cover and land use heavily influenced weed invasions. Where shrublands were close to human modified landscapes ,weed invasion increased, and the same when shrublands were close to rivers. Modified landscapes typically had a higher number of weed species, providing a seed source that can then move into more natural areas.

Size and shape of shrublands matters. Shrublands with long edges experienced higher levels of weed invasion, with edges often having more disturbance and being more accessible to invaders. This is known as an “edge effect“. Topography is another contributor, with lower and flatter areas more invaded than those that are steep and/or at higher elevation

Unsurprisingly, climate also played a major role. Warmer temperatures were shown to increase weed invasion, and many introduced plants thrived in mild conditions. The expansion of suitable habitat ranges of weeds through a warming climate is yet another reason to be concerned about climate change!

Scrubland on Onawe Peninsula, Banks Peninsula. Photo by Adrian Paterson

Lastly, these researchers found that no single factor could fully explain weed invasion, it’s all about a combination of various factors. Something that readers might have expected.

Through my work in conservation I’ve been lucky enough to spend time in a range of shrublands. Some of the most special are the fragmented remains of the once extensive kanuka drylands of the Canterbury Plains, such as Motukānuka Scientific Reserve. Research has found that intensive land use change adjacent to these remnants has strongly contributed to increased weed invasion on the edges. Irrigation changing water availability and increased nitrogen availability from surrounding farms were attributed as two of the main drivers here.

There’s a couple things we can learn from these studies when thinking about protecting shrublands. To reduce the impacts of exotic plant invasion, the larger the area of shrubland the better. Dense, structurally rich vegetation is going to be more resilient to invasion. However, often small fragments of biodiversity are all that are left to work with, so factoring in a buffer from surrounding land use then becomes important.

In many situations active management of weeds, such as physical control using herbicide, is essential to protect native species and ecosystem function’s from their impacts.

So now that you know a bit more about shrublands, keep an eye out for some of the features discussed here. Keep learning about the native and introduced plants of New Zealand, and get out there with the right people and deal to some weeds!

This article was prepared by Will Todhunter, Postgraduate Diploma in Applied Science student, for an assignment in ECOL608 Research Methods in Ecology.

Rossignaud, L., & Hulme, P. E. (2023). Native vegetation structure, landscape features and climate shape non-native plant richness and cover in New Zealand native shrublands. Diversity and Distributions, 29(8), 1009–1020. https://doi.org/10.1111/ddi.13713

July 29, 2026
The three bird-iteers: all for monitoring and monitoring for all!

My time at Lincoln University has taught me that when it comes to bird monitoring, the most common practice is the 5 minute bird count (5MBC). This method is a simple and effective way of counting birds within a specific area by recording sightings and calls. Much of the time, using 5BMC, it is likely that you will not see the bird you are hearing, which is why being able to identify New Zealand birds just by sound is a very good skill.

Lincoln University legend Jon Sullivan did a study on different bird data collection methods that could also mahi together to build a more accurate picture of birds in an area. The study focused on wider Christchurch, beginning in 2003, and recorded patterns in bird species within the area.

One method that was used was the stationary method , which is pretty much the same as the 5MBC but is extended to 20 minutes. The other method used was the ‘mobile method’, also known as the ‘line-transect method’, where you collect data while moving at a fast pace, perhaps by bike, car, or running.

Now to the fun stuff – birds!!

In Jon’s study there was a focus on three bird species, which I call the three bird-iteers (with apologies to Alexandre Dumas). These are the grey warbler, fantail and the bellbird. These endemic birds are very adaptable to recent changes for forest bird species.

Grey Warbler

The grey warbler (Gerygone igata, riroriro) are found throughout New Zealand. They are small, grey/brown with a more pale shade of grey for the face to throat. They weigh approximately 6.5 g (lighter than a mouse) and their diet consists of insects and spiders.

Grey Warbler. Photo CC BY Mikullashbee, Flickr

Fantail/pīwakawaka

Fantails are one of my many favourite bird species, as they love to follow humans around when you are on bush walks. Fantails are able to adapt to environments that have been changed by humans, which is not very common for New Zealand native birds. Fantails (Rhipidura fuliginosa, piwakawaka) are often found in open native bush, exotic plantation forests, orchards and gardens. Their diet consists of insects, especially small species. Fantails are a small bird about the size of a house sparrow, but what makes them so distinctive? Well the answer is in their name…. Yes their tails, like their name suggests they have a long tail that fans out like a well a fan.

Fantail. Photo CC By Chris S, Flickr

Bellbird/ Korimako

Bellbirds(Anthornis melanura, koromiko)are commonly found in the South Island. These birds have a short, curved beak and are green with a slightly forked tail. Bellbirds, similar to Tūī’, have a distinctive song, it is like a high ringing that’s also kind of smooth, and the repeat the same tune. Bellbirds reside throughout native and exotic forest, scrubs and shelter belts of New Zealand. Their diet is nectar from native and exotic plants, although they do consume fruit in late summer and autumn. Also their diet consists of honeydew that’s found on beech trees.

Bellbird. Photo CC By Glenda Rees, Flickr

Back to the study

Jon Sullivan wanted to understand how nature responds to a forever changing world. He collected distribution and abundance information for many species with these three species being the focus. This is where the methods came into play as a standardised method and a repeatable one is needed to accurately tell us if a species is present or not. The methods talked about above were to work alongside each other.

Around 100,000 bird counts were collected. The approach used helped to summarise data that was from one location, a certain time each week, and one daily route. The results showed that this approach was effective and just as effective as the 5 minute bird count. Counting birds while riding your bike along a road was just as effective at estimating and following trends as more traditional methods.

Fantails, grey warblers, and bellbirds (but not to the same extent as the other 2) are majorly restricted to their forest biotopes and native plantings, particularly in spring.

Like any good study, more data are needed to get a better and clearer understanding. This could create a good opportunity at Lincoln University to teach students doing ecology to learn how to use different techniques besides just the 5MBC methods. Then we too can collect decades long information on our favourite birds.

This article was prepared by postgraduate student Caitlan Christmas, Masters of Science in Ecology and Conservation, for an assignment in ECOL608 Research Methods in Ecology.

Sullivan，JJ（2012). Recording birds in real time: a convenient method for frequent bird recording https://researcharchive.lincoln.ac.nz/server/api/core/bitstreams/04dc8df3-2e34-4fe9-96a6-ea8a505ad0cc/content

November 11, 2025
Amaizing distribution: nematode infestations of NZ corn

Are your maize plants growing well in the field? If not,we can often blame plant parasitic nematodes.

There are around 4100 known species of nematodes and they cause a considerable loss of agricultural produce, with estimated global crop damage of $US 358 billion every year.

The life cycle of these plant parasitic nematodes have four stages, and the second-stage juvenile (J2) is the destructive phase. Most nematodes are sedentary inside the host and others survive in the soil.

Written by Sambath in behavior, conservation, front page profile, invasive species, student blog, Uncategorized, zoology, pest management

In the 2021/22 NZ growing season, about 196,000 tonnes of grain and 1,200,00 tonnes of silage were harvested, making maize one of the most cultivable crops in New Zealand. Around 58% of the harvest was grown for livestock feed demand, and the remaining 42% was for food and industrial processors.

Plant parasitic nematodes are common in New Zealand and many horticulture industries have experienced a substantial loss of profits from these destructive plant pests. While maize is one of the most crucial crops in this country reported to be damaged by various species of nematodes, few studies have been conducted here compared to other countries.

So, Nagarathanam Thiruchchelvan, a PhD student at Lincoln University, and his team conducted research to identify and quantify plant parasitic nematode infestations of maize production across New Zealand. Their purpose was to investigate the prevalence and diversity of several genera of plant parasitic nematodes.

Plant parasitic nematode feeding types. Image from Paulo Vieira & Cynthia Gleason

The researchers collected a total of 384 composite soil samples from 25 maize fields located in the North and South Islands, focusing on: Canterbury, Waikato, and Manawatu-Whanganui. Data collection was carried out at various maize growing stages and seasons during 2022.

It was not good news!

The researchers found that at least one genus of plant parasitic nematode was detected in 378 (98%) of the maize samples. Pratylenchus was the most prevalent and widespread genus (91%) followed by Helicotylenchus (38%).

Plant parasitic nematode. Image from Scot Nelson

The plant parasitic nematode population and diversity were higher in Canterbury than in Waikato and Manawatu-Whanganui. Thiru and his team believed that the inconsistent distribution was caused by different climate and geography conditions between the two regions. For example, the South Island is more diverse in soil physiochemical proportions than the North Island.

Thiru also observed that soil orders, a soil classification system, affected the proliferation of plant parasitic nematode populations, with brown and pallic soil types promoting nematode reproduction, especially for Pratylenchus. Pallic soils refer to a soil type having pale, fragile topsoil and compacted subsurface. For the brown soil, its topsoil is dark grey-brown, and the subsoil is tan or yellowish-brown.

The lowest number of plant parasitic nematodes was detected in organic soil. Organic-rich soils favor a wide range of beneficial fungi, bacteria, and nematode survival. These microorganisms can suppress the proliferation of plant parasitic nematodes by either feeding on eggs or predating invasive nematodes.

The study further indicated that the population and diversity of plant parasitic nematodes increased alongside distinguishing developmental stages of maize. Most nematodes were reported from the harvesting stage, while the least were from the seedling stage.

Root-knot nematode (Meloidogyne enterolobii). Image from Jeffrey W

Thiru and his team noticed that rotating maize with other crops played a significant role in reducing the incidence and prevalence of plant parasitic nematodes in the field. These other crops included ryegrass, pasture, wheat, white clover, potato, peas, and winter crops. One maize field located in Canterbury was detected with a high significant intensity of 3000 nematode root lesions per kg of roots as a result of non-rotation practice.

Thiru concluded that there was a requirement for a deeper understanding of dispersal, feeding characters, and life cycle of plant parasitic nematodes, in particular, root-lesion nematode (Pratylenchus) in maize fields across New Zealand. Specific pest management approaches are needed to control the prevalence and abundance of targeted nematodes impairing maize production in both islands.

These article was prepared by Sambath Seng, a Master of Science student in the Department of Pest Management and Conservation at Lincoln University.

Thiruchchelvan, N., Kularathna, M., Moukarzel, R., Casonato, S., & Condron, L. M. (2024). Prevalence and abundance of plant-parasitic nematodes in New Zealand maize fields: effects of territory, soil orders, crop stage, and sampling time. New Zealand Journal of Zoology, 1-22. https://doi.org/10.1080/03014223.2024.2424900

November 6, 2025
Silent hunters on the wetland edge: urban cats and nature conservation

The dark side of the cat

Cats doing what cats do.
Photo by Robert | Visual Diary | Berlin on Unsplash

In the autumn evening, a cat lies on the fence, with focused eyes and slightly wagging tail, this patient hunter is quietly locking onto a target and preparing to attack.

Cats are the standard feature in almost neighbourhoods in New Zealand. They are elegant, lazy, affectionate, and sometimes unpredictable. Some of them are pretty welcomed , moving freely around neighbourhoods everyday, accepting feeding and petting.

Behind these soft furs and friendlypurring, there is an ancient, untamed instinct hidden – hunting. Hunting is not just about hunger. Most cats were are well-fed—some are even fed multiple times a day. Yet, the urge to stalk, chase, and kill remains.

Travis Wetland: A natural island in the city

Wetlands, green spaces, and bushes are the last shelter for local plants and animals. These “ecological islands” are often located right next to the communities where we live.

Travis Wetland is a freshwater ecological oasis, located on the edge of Christchurch. Surrounded by residential areas, roads, and commercial development, it remains a vital refuge for more than 53 species of birds and many native invertebrates.

Living around this wetland, there are hundreds of free-moving domestic cats living. They can walk through the grass without permission, quietly enter the ecological core area, and become hunters of these small lives.

A Patient Hunter
Photo by Kristin O Karlsen on Unsplash

Silent pressure & hidden trail

It is easy for people to imagine a cat lazily lying in the sun by a windowsill, but what about the other side of their life when they step out the door?

Over the course of a year, 21 pet cats living near Travis Wetland were installed with GPS collars as part of a study by Lincoln University and the Christchurch City Council. The research, led in part by Shelley Morgan and Adrian Paterson, revealed some surprising results.

Researchers did not capture many cats with prey in their mouths (although more than a few did bring their prey back to their home). But there were other situations: cats were often visiting the edge of the ecological core of the wetland, where native birds, lizards and insects breed.

Fantail(Rhipidura fuliginosa)
Photo by Callum Hill on Unsplash

The cat threat does not necessarily come from killing, sometimes, just “attending” is enough. Birds may abandon their nests if they sense a nearby predator. Lizards may interrupt their mating if they feel targeted. In nature, energy is precious, and fear itself is also consumes energy.

More than half of the monitored cats entered Travis wetland at least once. Some of them went more than 200 metres into the wetland while their owners sleeping, crossing habitats and breeding areas for rare native lizards, insects and ground-nesting birds.

More than half of the monitored cats entered Travis Wetland at least once. Some of them went more than 200 metres into the wetland while their owners sleeping, crossing habitats and breeding areas for rare native lizards, insects and ground-nesting birds.

But not every cat causes the same amount of harm.The study found that younger cats—those under six years old—were more active and risky. They travelled further, spent longer inside the wetland, and brought home more prey. Some even swam across water to reach nesting islands. In contrast, older cats tended to stay near home and moved less.

A small number of energetic cats were doing most of the damage. Researchers called them “super-predators”. This suggests that cat behaviour and age both matter. While most cats seem harmless, a few individuals can quietly cause serious impacts to local wildlife.

This means the cat you see curled up by the fireplace in the afternoon may be walking the narrow line between urban life and ecological harm at night. It’s not the cat’s fault, and it’s not your fault, but it’s keep happening.

Cat by the Window
Photo by Aleksandar Popovski on Unsplash

Night walkers & tiny bells

Cats are typical “crepuscular” animals, that is, they are most active in the dawn and dusk. This explains why you see cats running around the living room at 10 pm or staring at the wall at 5 am. They don’t listen to a clock, they listen to the call of instinct.

Sunset and just after is also the time when many cats go out for their “night patrols”. According to the data from the study’s cat GPS tracking, cats move more frequently and walk farther at night. Some cats hardly go out during the day, only sneaking through the garden and visiting the fields after dark.

So, what can we do to reduce the impact of out furry friends? Some owners hang small bells on their cats’ collars, hoping that the sound will alert potential prey and give them time to escape. This method seems simple and effective, but the effect actually varies from species to species.

There is a study by University of Otago have shown that bells have a certain deterrent effect on birds and the study by Geiger shown that have little effect on lizards or insects because they are not sensitive to sound. Also some smart cats can even learn to “walk silently” – so that the bell doesn’t ring at all.

Nightwalker Cat
Photo by amir esfahanian on Unsplash

So, while bells may help a little, they are not a panacea. As with everything in this story, the answers are never simple.

Draw a ceasefire zone

Some solutions are simple, and others need some creativity.

In some parts of New Zealand, there is talk of creating a cat-isolation buffer zones — areas around nature reserves where cats are either required to be kept indoors full-time, or where cats are banned or a curfew(Wellington City Council. 2024) is imposed on cats near reserves (although curfews seem not work for protecting birds or lizards)

This idea is not to punish cat owners but to protect the most vulnerable parts of the ecosystem. Because may be the problem is that house cats may be found curled up in warm blankets, purring softly, eyes half-closed, and when just hours earlier, those paws may have landed a fatal blow on a small bird, or pinned a native skink to the ground.

Free-roaming cats in New Zealand are subject to different local management depending on their relationship with humans (such as companion cats, stray cats, and wild cats), but there is currently a lack of unified national laws(Sumner, C. L. 2022).

Threatened-Nationally Critical Skink: Alborn Skinks(Oligosoma albornense)
Photo by James Reardon

Some newly built areas even state in the purchase agreement that cats are not allowed to roam freely, and sometimes even completely prohibit cats(Preston, N. 2023).

To some people, such regulations may sounds really extreme. But to naturalists, it is a way of respecting boundaries, a quiet commitment to leave even a small area and keep distance for the creatures that have lived here long before we came here.

We would much rather have this scenario: ‘In the autumn evening, a cat looks out of a window at a fence, with focused eyes and slightly wagging tail, this patient hunter is quietly locking onto a target that it would love to attack. Frustrated, it curls up and goes back to sleep.’

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

Research paper: Morgan, S. A., Hansen, C. M., Ross, J. G., Hickling, G. J., Ogilvie, S. C., & Paterson, A. M. (2009). Urban cat (Felis catus) movement and predation activity associated with a wetland reserve in New Zealand. Wildlife Research, 36(7), 574–580. https://doi.org/10.1071/WR09023

References

Geiger, M., Kistler, C., Mattmann, P., Jenni, L., Hegglin, D., & Bontadina, F. (2022). Colorful Collar-Covers and Bells Reduce Wildlife Predation by Domestic Cats in a Continental European Setting. Frontiers in Ecology and Evolution, 10. https://doi.org/10.3389/fevo.2022.850442

Housing development near Auckland imposes cat ban to protect wildlife. (n.d.). 1News. Retrieved 5 May 2025, from https://www.1news.co.nz/2021/08/11/housing-development-near-auckland-imposes-cat-ban-to-protect-wildlife/

Preston, N. (2023, July 1). No cats allowed: Growing number of new neighbourhoods banning pets. Oneroof. https://www.oneroof.co.nz/news/no-cats-allowed-growing-number-of-new-neighbourhoods-banning-pets-43855

Responsible cat ownership. (2024, October 17). Wellington City Council. https://wellington.govt.nz/dogs-and-other-animals/cats/responsible-cat-ownership

Sumner, C. L., Walker, J. K., & Dale, A. R. (2022). The Implications of Policies on the Welfare of Free-Roaming Cats in New Zealand. Animals, 12(3), Article 3. https://doi.org/10.3390/ani12030237

October 22, 2025