Category: community ecology

  • Bats at the crossroads (with tears in my eyes)

    Bats at the crossroads (with tears in my eyes)

    Being a born and bred southern man from South Otago, crying is not something that I do much (or was encouraged to do).

    There are some things that make the eyes prickle, though. Movies can certainly do it. Aragorn telling the hobbits “My friends, you bow to no one” in The Return of the King is certainly is up there. The last “That’ll do pig” from Farmer Hoggett in Babe has always gotten me. The final soaring ending of The Last of the Mohicans as Hawkeye and Cora gaze out over the forest clad hills brings the shiny eyes. The speech from young Paikea about her grandfather in Whale Rider was emotional enough in 2002, now that I am a koro myself with a granddaughter, I can only imagine it would be even more devastating.

    In reading books I am a lot more immune to tears. There are, however, a few passages in The Lord of the Rings that will make the eyes water. One of them is in my most favourite section in the trilogy.

    Tucked in towards the end of The Two Towers is the chapter Journey to the Crossroads. The last section, just over a page long, tells how Frodo, Sam and Gollum finally arrive at the crossroads. They have been sneaking through the gloom of Ithilien for the whole day, in an absolute unnatural quiet, broken occasionally by distant thunder or drums. They are scared and dejected. They arrive at the crossroads where, once they pass them, they will be committed to walking past Minas Morgul and into Mordor.

    An old statue and surrounding walls have been vandalised by orcs at some point and all is in disrepair. Everything is sombre and Frodo is filled with dread.

    The King at the cross-roads (Darrell Sweet)

    At that moment the sun drops below the ash-cloud cover and shines a light on the scene, picking out the fallen head of the statue and the pretty flowers encircling it like a crown.

    “They cannot conquer for ever!” said Frodo. And then suddenly the brief glimpse was gone. The Sun dipped and vanished, and as if at the shuttering of a lamp, black night fell.”

    Cue the lump in the throat. It’s the hope that gets you.

    There is another reason why I like this chapter so much. The hobbits are travelling through Ithilien, a beautifully lightly wooded region next to the Mountains of Shadow. Mostly the malign influence of Sauron has been kept to a minimum. There are always signs that Orcs have been up to mischief and that the local environment is beginning to suffer from Orc impacts. As the trio move closer to Minas Morgul, a source of orcs, pollution of the local rivers, and general environmental callousness, we start to see greater impacts on nature.

    In my humble opinion, one of the best and most moving passages in the Lord of the Rings.

    And then the sun shines for that brief moment and the Hobbits see that there are still beautiful plants growing and flowering, even in these areas of high impacts. Nature can persist in the face of ongoing Orcanisation.

    Over the last few years, much of my research has involved looking at the impacts of anthropogenic (human) impacts. These impacts are often through urbanisation – building suburbs everywhere -and on local species in the environment. Research has ranged from how blackbird behaviour changes from the town to the country, to how kea and black-fronted terns respond to farming-use changes in the environment.

    While we have a focus on impacts on birds in New Zealand, bats are a group that are often looked at in other parts of the world. Bats move around the landscape and will almost always come into contact with anthropogenic impacts in their travels. Bats are often a good indicator species for any local problems caused by humans.

    Much of the work on bats has been done in Europe and often around major cities, typically in low altitude flat areas. Lincoln University Master of International Nature Conservation student Quinn O’Halloran had the opportunity of collecting data on bats in the South Tyrol landscape of the northern Italian Alps. Quinn joined a long term data collection project in the EURAC Institute for Alpine Research.

    After a summer spent surveying for bats (using bat detectors that can record their calls) Quinn was given access to six years of data from 320 sites, focussing on 32 urban settlement sites and spent her thesis time analysing this information. Quinn wanted to find out how bats responded to urbanisation of these alpine valleys where the human population has grown over a large area in the last few decades.

    Image from Valentin Heimer (EURAC Research)

    Quinn was interested in how variables impacted the activity and diversity of bats in these areas. She looked at the influence of factors like the amount of hard surfaces and woodlands, distance to woody patches and rivers, access to old buildings and so on.

    In a paper published in Global Ecology and Conservation with her Lincoln supervisors Adrian Paterson and Jon Sullivan and European advisors Chiara Paniccia and Tanja Straka, Quinn showed that the alpine landscape seemed to change things.

    Typically, urbanisation has a big impact on bat diversity and numbers. There are a few bats that do well with human changes but most don’t and so there is a clear signal that cities are not great for bats.

    Image from Andrea De Giovanni (EURAC Research)

    In the South Tyrol this was not the case. Quinn found that bat diversity and activity was much higher than expected, even with bats that typically don’t do as well in urbanised environments in other parts of Europe. It seemed that there was enough access to woody patches, water and green areas in these alpine environments for the bats to be less impacted than in other places.

    It is likely because of the three dimensional landscape of the alpine environment. The South Tyrol has a landscape of deep glacial-cut valleys (flatfish bottoms and steep sides). People live and build in the valley bottoms but they don’t make it far up the sides (even to farm) as they are very steep.

    For a flying bat this is not such a problem and so they have access to somewhat wild areas not too far way up the valley walls. This access is enough to counter some of the urban impacts that are problems for bats living in cities on open plains where there are few wild areas. Quinn was able to show that bats and human changes in the environment respond in different ways depending on the landscape.

    Image from Harriet Taylor.

    So, much like Frodo and Sam at the crossroads, there is always hope. Urbanisation can seem like an overwhelming problem for our native diversity, and it often is. But we also need to remember that not everywhere is the same and that species are often more resilient than we think (or at least better at finding and using resources in the local environment than we expect).

    Nature is robust, and, sure, it will accept help where we give it. But nature is not just a victim, it can also help itself as well. And that’s a hopeful message.

    Now, if that doesn’t bring a tear to your eye then I don’t know what will.

    When Adrian isn’t choking back the tears he is a lecturer at Lincoln University.

  • Could spiders be our crop protectors?

    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, 2023)
    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.

    DES Daughter, CC BY-NC-SA 2.0
    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

  • A fiery topic: shining light on the  acacia understorey

    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

  • The war beneath your feet: soil decides the fate of plants

    The war beneath your feet: soil decides the fate of plants

    You stride through lush grasslands. The scenery seems perfect. But lurking just below your feet is a battlefield.

    It’s not an obvious one, of course. There are no bombs going off or explosions or yelling; but there are millions of tiny creatures locked in battle for resources and life. And whoever wins determines whether the plant life above it survives.

    This blog post has been inspired by research published in 2015 by scientists of Lincoln University, AgResearch, and their international colleagues. They examined whether soils from different pastures in New Zealand naturally inhibit soil-borne plant pathogens.

    Figure 1. Grass roots penetrating the soil. The majority of activities that affect plants occur below ground level. Source: iStock/Getty Images

    The Invisible Threat

    Many important plant diseases originate underground rather than from the aerial parts of plants, such as leaves. They attack plant roots and stems before visible symptoms appear above ground. By the time one notices any symptoms of disease, the damage may already have been done.

    And here is the scary part: these silent killers can reduce pasture productivity by 40–50%. Can you imagine how devastating it is to lose nearly half of your production to something unseen? Such is the case in pastures where crop rotation and chemical controls cannot always solve the problem.

    Instead of asking the conventional question, scientists started to wonder:

    What if the soil could defend itself?

    Soil Is Not Just Dirt

    It is easy to think of the soil as lifeless material, but this is far from the truth. Soil is one of the most biologically diverse ecosystems on Earth. A complete microbiota lives within it: bacteria, fungi, and other microorganisms interact continuously. While some assist plants in absorbing nutrients, others … kill them.

    Some soils inhibit diseases. Such soils are referred to as disease-suppressive soils, and their action falls into two categories:

    General suppression: the microbiota competes with the pathogen,
    Specific suppression: some microbiota attack the pathogen itself.

    Soils with high plant diversity likely contain more diverse microbiotas, which suggests a high disease-suppression capacity.

    But how can one measure such a phenomenon?

    A Clever Way to Test Soil

    The researchers developed an interesting experiment to test the soil under examination. Rather than using conventional grass or legumes that can be found on pastures, they opted for something completely out of the ordinary: kale.

    And why kale? This plant is not usually used on pastures. If disease does not occur, then it shows that the soil is pathogen-resistant in general.

    Furthermore, they exposed the plants to a well-known pathogenic fungus named Rhizoctonia solani. And this one leads to a specific disease called damping-off. Plants affected by the disease exhibit dark lesions near the base of the stem which cause plants to fall, like broken wires.

    So, basically, the process works as follows:
    Introduce the same plant into different soils;
    Infect the plant with the same pathogen;
    Observe the results.

    Figure 2. Seedling damping off showing dark spots on stem bases. Seedling damping off may result in death of the seedling before establishment. Image credit: AA Seif and AM Varela, icipe. Source: CABI PlantwisePlus Knowledge Bank.

    All Soils Are Not Equal

    The experiment was conducted using four New Zealand pasture soils, including Lincoln, Eyrewell, Rotorua, and Kurow soils.

    Same plant. Same pathogen. Entirely different results.

    Some soils promoted rapid spread of pathogens; others reduced their effect considerably. There were significant differences between disease levels in the various soils.

    • Final disease levels were highest in Rotorua soil.
    • Disease progression rate was highest in Kurow soil.
    • Lincoln soil displayed maximum resistance, with minimal disease levels in the control.

    Same experiment. Different soil. Entirely different results.

    And here comes the moment when it all becomes evident:

    Soil is not just a neutral element. It actively influences the experiment.

    If a soil keeps plants healthy, it’s suppressive. If plants collapse… not so much.

    Figure 3. Sampling the soil is essential for research purposes on the properties and disease suppression abilities of soils. Image credit: William, Adobe Stock. Source: Farmers Weekly.

    The Twist: Some Soils Had Been Infected Already

    Without even having introduced the pathogen, some soils exhibited symptoms of infection. For instance, in Kurow soils, damping-off disease symptoms appeared in the control group as well. This indicated that the pathogen was already present but dormant until the required environmental conditions prevailed.

    It could be termed an underlying threat embedded in the soil. Furthermore, pathogens, such as Rhizoctonia solani, can survive between successive cropping seasons, affecting both pastures and future agricultural crop growth.

    It’s Not Only “How Many” but Also “How Quickly”

    Besides assessing how many of the plants became diseased, the authors also took into account the dynamics of disease development. Why does this matter?

    This is important because a slowly developing disease will allow the plants to develop properly before being affected. The faster moving disease will kill them much earlier.

    Two metrics were used to assess this:
    Disease Incidence (DI) – number of infected plants at the end;
    Area Under Disease Progress Curve (AUDPC) – a measure of disease development over time.
    Imagine that:
    DI is the final result
    AUDPC is the whole game
    And often, their narratives may be very different.

    Why It All Matters

    It isn’t just scientific research for research’s sake. With knowledge of how soils resist disease, we could:

    • Improve our soil management techniques,
    • Cut down on chemical use,
    • Increase productivity from our crops and pastures,
    • Create a more sustainable agricultural process.

    Rather than battling pathogens directly, we could fortify our soil against disease.

    That’s where it gets revolutionary.

    The Bigger Picture

    Agriculture of the future may rely less on adding things to soil…
    And more on what is already thriving beneath its surface.

    When you look at a flourishing farm, remember this:
    It is not only the plants that prosper. There is an entire ecosystem underground, sustaining all life. And in this unseen world, each microbe counts in the battle beneath our feet.

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

    References:

    Dignam, B. E. A., O’Callaghan, M., Condron, L. M., Raaijmakers, J. M., Kowalchuk, G. A., & Wakelin, S. A. (2015). A bioassay to compare the disease suppressive capacity of pasture soils. New Zealand Plant Protection, 68, 151–159.

    http://www.nzpps.org/nzpp_abstract.php?paper=681510



  • If friend-shaped, why not friend?

    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.

  • More than teeth: mouth microbiomes of stoats and possums

    More than teeth: mouth microbiomes of stoats and possums

    Like most people, I hate going to the dentist. Every time I have a check-up, they poke and prod around my mouth, trying to find something wrong. Most of the time, they end up telling me the same thing: I don’t floss enough.

    Despite all those check-ups and the money that went into braces, I rarely find myself thinking about what actually goes on inside our mouths. They are the first point of contact for everything, from breaths of fresh air to the good (and bad) choices about what we eat. But our mouths have a lot more going on than we credit them with.

    Our mouths are home to over 700 different species of microbes – tiny microscopic organisms that can be anything from bacteria to fungi to viruses. While that might sound like a bad thing, these microbial communities contain both helpful and harmful organisms. Many beneficial microbes assist with digestion and help regulate harmful microbes, even in food!

    Our mouths are home to hundreds of different microorganisms. Image from Tjandrawinata et al., (2025) licensed under CC BY 4.0

    These diverse oral communities exist in almost all animals, and their roles go far beyond digestion. They can also influence immune responses and even host behaviour. In turn, oral microbiomes themselves are shaped by a host’s genetics, physiology, environment, and diet. As microbiomes co-evolve with their hosts, we can potentially understand genetic variation and evolutionary processes in host species by looking at these small passengers.

    Common Brushtail Possum (Trichosurus vulpecula) – JJ Harrison (CC-BY-SA-2.5)

    These interesting, yet poorly understood, communities were studied by a group of nine scientists, including researchers from Lincoln University. They wanted to understand the oral microbiomes of two invasive to New Zealand mammals: the stoat and the common brushtail possum. Stoats and possums are both notorious pests in Aotearoa. They disrupt our vulnerable ecosystems, killing native plants and animals. While extensive research has examined the species themselves, little attention has been given to their microbiomes, let alone their oral microbiomes.

    Stoat (Mustela erminea) – James Lindsey (CC BY-SA 3.0)

    Led by Arsalan Emami-Khoyi, the researchers aimed to characterise the diversity, content, and variation of oral microbiota in the animals. With ethics approval from the Lincoln University Animal Ethics Committee, they live-captured five stoats and five possums from Banks Peninsula. Unlike a typical trip to the dentist, the animals were sedated before researchers swabbed their mouths. The researchers then used a DNA technique called 16S rRNA metabarcoding to discover and record microbial communities. This complex technique identifies the abundance of different groups of microbes.

    All of the animals captured were healthy apart from gum inflammation – my dentist would be horrified by how little they brush their teeth. As published in the journal Diversity, the researchers identified 19 different major microbial groups (phyla), and 51 known species in the animals’ mouths. Despite this high diversity, a small number of microbes dominated each mouth fauna in both animals. These same groups are abundant across other mammal species, representing a ‘core’ set of microbes across mammals. Some of these core groups are Proteobacteria and Firmicutes.

    The researchers also found clear differences in microbial composition between stoats and possums. This suggested a link between diet and microbes, with omnivorous possums having plant-metabolising bacteria, such as Treponema sp., which were completely absent in the carnivorous stoat. At the same time, the high diversity in both species suggests that other factors, such as genetics, environment and physiology, also play an important role in shaping oral microbiomes.

    The variation of the five core oral bacteria in stoats and possums found in the study (CC BY 4.0).

    This high variation in the oral microbiome could help us understand evolutionary responses of introduced species to new environments. Because of their short lifespan and fast reproduction, microbial communities can change more rapidly than their host genetics. So focusing on them could teach us about how much these invasive species have adapted to New Zealand’s environment.

    Understanding the oral microbiomes of these invasive mammals could also have practical applications in pest control. Microbes can influence how animals process toxins and other chemicals, which may influence how well poisons work. In New Zealand, we often rely on poisons, such as 1080 and brodifacoum, to control our mammalian populations. Future research on this could help us improve the effectiveness of control tools.

    Work has already been done beyond this study. The lead author and colleagues have developed a device that collects DNA from possums in the field, allowing us to sample DNA without capturing the animal directly. Alongside collecting host DNA, this approach can also provide insights into possum health by analysing oral microbial DNA.

    The device developed by Arsalan Emami-Khoyi and colleagues for capturing DNA in the field (Arsalan Emami-Khoyi et al., 2021)(CC BY 4.0).

    Personally, I think this study could help us understand population connectivity. Comparing microbial samples from different locations could provide a new way to understand population connectivity and how invasive species spread.

    There is a wide range of potential applications from this research, and microbiomes will likely play an increasingly important role in future pest management.

    It turns out we can learn a lot from what’s happening inside an animal’s mouth. So maybe my dentist is right to look so closely after all.

    This article was prepared by Master of Bioprotection student  Sam Bonney as part of the ECOL608 Research Methods in Ecology course

    Emami-Khoyi, A., Benmazouz, I., Paterson, A. M., Ross, J. G., Murphy, E. C., Bothwell, J., Alizadeh, H., van Vuuren, B. J., & Teske, P. R. (2020). Oral Microbiome Metabarcoding in Two Invasive Small Mammals from New Zealand. Diversity, 12(7), 278. https://doi.org/10.3390/d12070278

  • Polka dots, patches and pinstripes? Productive pasture patterns

    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.

  • The shrubland invasion: What’s driving it?

    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.

    A natural landscape featuring a mixture of shrubs and grassy terrain, with a mountainous background under a cloudy sky.
    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.

    Dense forest scene with bare trees and lush green undergrowth.
    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

  • Our plants are not being poisoned by 1080 possum baits

    Our plants are not being poisoned by 1080 possum baits

    I’ll admit, before taking the 16 hour flight from Arizona to Christchurch, I didn’t know much about New Zealand besides ‘What We Do in the Shadows’, Karl Urban, and affordable yarn. I was especially excited to get my hands on possum yarn.  

    Possum yarn is coveted by the knitting community for its lightweightedness and warmth, only surpassed by the fur of arctic foxes and polar bears. And let me say that I absolutely think that the possum yarn was worth every dollar. With just 400 meters (one skein/ball) I was able to knit up a cabled hat, mittens, and still have some left over for some ankle length socks!  

    The feeling of possum yarn is incredibly soft and the natural brown color of the possum fur mixed with merino sheep wool makes for a more muted (in a good way) color palette. However, I recognise that the brushtail possum is a prevalent pest in New Zealand; so much so that drastic measures like Compound 1080 poison baits have been used since the mid-1950’s to control this introduced species. 

    Common Brushtail Possum by Catching The Eye, 2014 (CC BY-NC) 

    Compound 1080 for pest control in New Zealand 

    To put it simply, sodium fluoroacetate (AKA Compound 1080) is a vertebrate pesticide used to control introduced mammal species, such as rats, mice, feral cats, and possums. Without Compound 1080, these species decimate the population of endemic plants and animals only found in New Zealand. The compound is dispersed by aircraft(i.e. helicopters or fixed-wing planes) in either a carrot or cereal bait.  

    According to my professors, everyone has an opinion on the use of 1080. While Compound 1080 is great when it works, there are concerns from both the general public and Māori communities. From a public perspective, 1080 does have the real danger of killing people’s cats and dogs if accidentally ingested. As a pet owner myself, this is especially scary because my cat and dog would likely eat the bait before I’d have a chance to recognise what it was. Additionally, the Māori community has concerns about Compound 1080 leaching into the soil and then poisoning plants used for food or medicinal purposes.  

    Back in September 2003, a cooperative effort was made in New Zealand by the Ecology Department at Lincoln University, Landscape Research, Lake Waikaremoana Hapu Restoration Trust, and the Tūhoe Tuawhenua Trust to determine if Compound 1080 negatively impacts plant species used by the Ngāi Tūhoe Māori and if not, how to get this information spread among the iwi. To achieve this, a study was conducted on wild-growing pikopiko (AKA hen and chicken fern) and Karamuramu plants in State Forest Block 100, just south of Lake Waikaremoana. 

    Hen and Chickens Fern – Asplenium bulbiferum by John B, 2016 (CC BY-NC) 

    Ten individuals of each plant species were chosen and placed underneath wire mesh as protection against herbivory. Of the twenty plants, 3 of each species were exposed to a single Whanganui No. 7 cereal 1080 bait. Samples were taken from the plants throughout the study (days 0, 3, 7, 14, 28, and 56) as well as bait samples at the very beginning and end, to test for potential shift in potency over time.  

    More than 99% of the 1080 had disappeared from the baits by day 56 and all but one plant sample had no remaining amounts of 1080 within their systems. Of the twenty plants sampled, only one Karamuramu plant retained the toxin; and that was at most 5 parts per billion (ppb) and was completely gone by day 28.  

    Foodweb database 

    Karamuramu plant – Coprosma robusta by eyemac23, 2025 (CC BY-NC) 

    I don’t know about you, but I’ve never been a huge fan of reading scientific articles. They’re always confusing, too long, and to be honest, a bit dry. Sometimes I wish I could, instead, just scroll through a presentation with all the information presented short and sweetly.  

    Oh wait, this article did just that and made up not only a comprehensive food web on the interactions of the forest environment with 1080, but also added hyperlinks to it that opens a PowerPoint!(Note: the article did not include the link to the original PowerPoint, only an image of one of the slides.) Each PowerPoint slide focuses on a single plant or animal species impacted by 1080, the intensity of 1080 impact, and additional reference sources. It’s easy to digest and leaves room for more research if one wanted to do so.  

    Concerns from the Māori community 

    In conclusion, I get why using Compound 1080 is necessary against invasive species, like the brushtail possum and it will likely never impact me on a personal level unless it somehow leaches into a batch of yarn or something. However, I also can understand why the Ngāi Tūhoe Māori tribe are still hesitant as 1080 is still a toxin and we may not know the full impacts. While the decision to use Compound 1080 in the Te Urewera area is complicated, in 2016 those from the Ngāi Tūhoe tribe largely oppose aerial drops since it cannot be controlled.  

    Final thoughts 

    I think it’s important to note that for a 70 kg person to actually die from consuming 1080 that has remained in a Karamuramu plant, (and even in this example the probability of death is only 50%), they would have to eat 28 tons (28,000 kg) of the stuff. And that’s also if the plant is eaten raw, normally it’s boiled in water as a tea and diluted even more. Personally, after reading this I wouldn’t be too worried about Compound 1080 in my plants but I will still leave the risk assessment up to those in the Māori community on an individual level. 

    For now, I will continue to enjoy knitting with the luxurious possum yarn until the pests are eradicated from New Zealand once and for all.  

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

    OGILVIE, S.C., ATARIA, J.M., WAIWAI, J., DOHERTY, J., MILLER, A., ROSS, J.G. and EASON, C.T. (2010), Vertebrate pesticide risk assessment by indigenous communities in New Zealand. Integrative Zoology, 5: 37-43. https://doi.org/10.1111/j.1749-4877.2010.00190.x  

  • The three bird-iteers: all for monitoring and monitoring for all!

    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 (Gerygone igata)

    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

    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

    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