Category: student blog

Keeping up with the Kiwis: Translocations and their forever holiday homes
New Zealanders, also known as the ‘kiwis’, are known for tramping up great mountains, and travelling around the globe. For the actual kiwi bird, their adventures are limited to islands and protected environments. Even our New Zealand mascot, Goldie the kiwi, manages to ‘fly’ all around the world, which I’m sure would make the national birds jealous.

That’s not to say that actual kiwi don’t get around. Our national icon is the most translocated bird in New Zealand. We have been translocating kiwi since not long after the Treaty of Waitangi (1840) due to predation and habitat loss, often with limited success. When we try our hardest to save populations through transfers, most or all birds die. So, we created protected (fenced) sanctuaries that allow a safe environment for kiwi and other native species to thrive. But after decades of conservation work and relocating kiwis out of their homes to a safer habitat, are they truly happy in their new homes?

Fenced Sanctuary – Zealandia. Image by Russellstreet

Methods for successful translocations have been developed. Methods, including the introduction of Operation Nest Egg (ONE), allows the hatching chicks to become mature before releasing into the wild. These methods has required the involvement of community groups, iwi and hapū. However… there are no resources that include information from past kiwi translocations, so we don’t know the past outcomes, whether they were effective, or how to improve them — which is wild!

Researchers at Lincoln University, Peter Jahn and James Ross, and other colleagues reviewed 102 kiwi translocation projects (mainly from the last four decades — older information having been lost or ‘poorly documented’), and they examined the mitigation translocations and rehabilitation releases. But how do you define a ‘successful’ translocation?

We can’t assume that if we release birds into a new environment that everything will magically lead to success. We must investigate if the kiwi population can settle in, grow in numbers and maintain a healthy balance on their own for it to succeed long-term. The primary goal of translocations is to “establish or restore a population with a high probability of persistence”. Unfortunately, kiwi behaviours have made it hard to grow a population, as they are irregular breeders and take several years to reach sexual maturity.

To address this, objectives were set for releases:
- To grow all kiwi populations by at least 2% per year.
- To sustain genetic diversity, each translocation will have at least 40 unrelated individuals released (a ‘founder population’).
- A minimum timeframe of 15 years is required for the population to grow (and adapt to its new environment).
By collecting data and analysing the translocation trends over the decades, we can better understand how different projects affect the survival of kiwi taxa.

Stewart Island Brown Kiwi (Tokoeka). Image by Jake Osborne

Since 1863, there have been 102 translocations, with an impressive 76 kiwi translocations just in the last 20 years. Translocated kiwi species included: Rowi, Great Spotted Kiwi, Little Spotted Kiwi, Tokoeka, and Brown Kiwi. Most of the release sites (63% since the 1860s) were in the North Island or on offshore islands (sorry Lincoln — too much farmland). However, 20 of these projects’ reports do not exist or are unavailable. But here’s what is fascinating… just over half of the translocations (58%) introduced kiwi taxa where they were not seen before (a giant leap of ‘kiwi-kind’)!

In the past, effects to reduce harm for the kiwi were deemed as an ‘emergency’ to secure populations. Recent translocations cited ecological restoration and supporting kiwi taxa across different areas as a priority (which supports natural differences, and resilience – perfect for long-term conservation outcomes)!

Unfortunately, not all kiwi species have received the same level of attention. Those with more attention are spoilt with support (more management) and obtain an improvement in their conservation status. Other kiwi species are not as lucky, such as the Great Spotted Kiwi, Fiordland Tokoeka and Rakiura Tokoeka, as their conservation status has worsened. So even though translocation effort aims for an improvement in kiwi populations, other factors, such as population sizes and lack of predator control, make this already difficult job… even more challenging.

If you look at past scientific literature on initial survival of released birds, these translocations will be reported as ‘successful’, which seems good, right? But are they ‘self-sustaining populations’? Only one project (Zealandia) has been considered as ‘successful’ due to having an increased population. Even worse…. there is little information on the genetic make-up of the new population (which defeats the purpose of becoming a long-term project).

Little Spotted kiwi at Zealandia. Image by Kimberley Collins

For future translocations, the number of releases should be adjusted (by changing the total number kiwi released in a specific area) depending on the situation — for example, when there is a low founder population, or a high mortality rate. If a population is not looked after, this can result in reduced fitness and genetic variability. Having a database that holds the records of all the kiwi translocations would make it easier to analyse the factors that could influence kiwi populations.

So, what does the future hold for kiwi translocations? The main recovery goal, which was “restoring former distributions of all kiwi taxa”, has shown an increase in populations through translocations. Translocations have created new populations on islands, which can “fill in the gaps” in nature, which is a huge win! Guidelines suggest releasing 40 kiwi into a new population and that they are not related to the ‘founder population’ (this number can vary depending on specific factors to maintain high diversity).

As translocations start from newly established populations, it’s only through time that we will see if kiwi populations can further grow and maintain sufficient genetic diversity.

This article was prepared by Master of Science student Jessica Przychodzko as part of the ECOL608 Research Methods in Ecology course.

Jahn, P., Fernando Cagua E., Molles, L. E., Ross, J. G., & Germano, J .M. (2022). Kiwi translocation review: are we releasing enough birds and to the right places? New Zealand Journal of Ecology, 46(1): 3454. https://dx.doi.org/10.20417/nzjecol.46.1
September 4, 2025
Forests from grass: natural regeneration of woody vegetation on hill farms

If you’ve spent any amount of time travelling around Aotearoa New Zealand, you will have noticed the abysmal amount of forest trees in much of our country. Pre-human New Zealand was almost entirely covered in indigenous forest. You may have heard that statement before, but let’s just appreciate it for a second. 96% of the North Island and 72% of the South used to be lush with native podocarps, hardwoods, broadleaves, and beech trees.

Over the course of our relatively short history, we eventually destroyed a massive 14 million hectares of indigenous forest to make way for housing, industry, and farms. We were particularly keen on clearing drier and more arable regions like Canterbury and Central Otago, which have lost nearly 90% of their original vegetation.

By 2002, only a quarter of that indigenous vegetation remained. Don’t get me wrong, I like living here, that people can make money here, and I like eating fresh food. But, damn, I also like breathing oxygen…

Looking around Akaroa Harbour, the hills have mostly been cleared of indigenous vegetation at one point or another since human arrival to the area (own photos).

In all seriousness, native trees play much more important roles than that. Native forests can protect us from wildfires, help us avoid droughts, increase soil, water, and air quality, reduce erosion, and provide habitat for unique native species that do their part in making all of these ecosystem services available to us. As well as that, the land itself, the rugged forests, and activities like hiking through native trees forms part of our cultural identity, not to mention a reasonable chunk of our tourism industry.

What’s more, our native forests store an incredible amount of carbon – an estimated 1.7 billion tonnes.

In order for New Zealand to transition to a low-emissions economy and reach its climate change targets by 2050, we need to plant a lot more trees …up to 2.8 million hectares’ worth. The Productivity Commission suggested that most of this land could come from marginal farmland. As it turns out, there is an estimated 2.8 million hectares’ worth of suitable hill country that could be converted to forest. Hill country is essentially steep slopes at higher altitudes. It’s referred to as ‘marginal’ farmland because the economic gains are quite low compared to other landscapes. Steeper gradients are prone to erosion, and high-altitude climates don’t always lend themselves to agricultural productivity.

Steep slopes at high altitudes are key characteristics of New Zealand’s hill country (own photo).

So, how do we go about converting hill country farmland into a thriving native forest? Pedley, McWilliam, and Doscher discuss the factors that we must take into account.

Hill country revegetation projects are tough for the same reasons as hill country farming is tough, there are costs associated with buying nursery-raised seedlings and then planting on difficult terrain. As Pedley and colleagues suggest, the cheaper alternative is to simply let nature do its thing. Allowing forests to regenerate naturally is a form of passive or minimal interference management (MIM). Landowners, especially farmers, are among the most well-placed in the country to protect and expand our country’s native forest cover, and MIM is an attractive solution to the costs.

When it comes to revegetating farmland, Pedley and colleagues point out two major considerations.

One difficulty is that pasture grasses often suppress native seeds from establishing, so it’s important to help the seeds get a head start. The easiest way to do this is with nurse crops, which shade out the grass, shelter the natives, and protect them from browsers (particularly possums and ungulates, like deer and goats). Nurse crops can be exotic or indigenous shrubs and trees, and even existing weeds, like gorse, can be made useful. This is because NZ natives generally prefer to start out in the shade, eventually growing tall enough to overgrow the nurse crops.

Next is the issue of livestock that can be detrimental to natural regeneration. It does depend on which livestock species you have and which tree species are regenerating. Cattle can be extremely destructive to new plants, paddocks, and pre-existing vegetation. Sheep, on the other hand, don’t really seem to make a difference, though they tend to snack on broadleaved species that are a necessity for a healthy forest ecosystem.

Cattle should be reduced or excluded entirely from a revegetating area. Sheep can be reduced or excluded until there are a good amount of established seedlings, which usually aren’t as palatable to them. Just don’t forget to also keep out those pesky possums and unwelcome ungulates.

Cattle can be destructive to pastures and newly planted vegetation (“Cow Path to the Forest” by Tristan Schmurr, CC BY 2.0)

The most important part of natural regeneration is that the seeds have to come from somewhere. This means that the existing native vegetation on your property is one of your most important assets. This is the ‘passive’ part of the process and the money-saver, because you won’t need to buy seeds or establish nurse crops – the trees have got it covered. The native trees will shade out the grass in the space directly adjacent, enabling the seeds to gain a foothold and gradually expand the forest. Fencing off this area, or the paddock the trees are in, is enough to start the process.

A fair warning though: promoting natural regeneration with MIM can be slow, particularly through grazed pasture. Pedley and colleagues detected an annual regeneration rate of 0.2% from 2003 to 2019 at a southern Banks Peninsula station. At a time when New Zealand desperately needs to plant more trees, MIM is one of the ways landowners with limited resources can contribute, though more active management strategies will speed up the process. For example, consider pest management to exclude browsers (e.g. trapping, hunting, or fencing) and supplementary planting, especially if your remnant vegetation is limited to a few individual trees or species.

Policy and the barriers to getting involved

Finally, especially for those of us in the political and conservation sectors, I think it is our responsibility to encourage native tree planting among landowners, while understanding their barriers to doing so.

The most obvious barrier in converting farmland to forestry is the loss of income, however minor it is. Landowners meeting certain land and forest requirements may be eligible to participate in the New Zealand Emissions Trading Scheme (NZ ETS). With one hectare of ten-year-old forest, you might earn anything from 8-24 NZU per year, depending on the tree species. If sold at $58 per NZU, that’s an annual income of $464-$1392 per year – for essentially leaving the land alone. These figures grow as the forest matures, and with better policy, these figures could grow even more.

Our policies currently favour exotics over natives, and plantations over constantly-regenerating forest. Not all models consider the amount of carbon stored in the forest understory, which is much denser and richer in a native forest compared to a pine forest. New evidence shows that native ecosystems store much more carbon than previously thought, and over a much greater period of time than pine species.

Mature beech forest understory (own photo)

Mature pine forest understory (“Mount Thomas pines” by Jon Sullivan, CC BY-NC 2.0)

Another barrier to entry is our individualistic culture around climate change action. Many sheep and beef farmers report that pro-biodiversity action is not necessarily about a lack of resources, but the belief that their actions don’t benefit their own farms, or that they aren’t helpful in the bigger picture. It’s important that we change this mindset, because 89% of New Zealand’s emissions are created by our primary industries.

MIM cuts costs, but adding more trees to your property and protecting them not only benefits the landowner and the immediate environment, but also the rest of the country. It benefits the natural resources on which we all rely, stabilises the landscape, and protects us from fires and droughts. Natural regeneration of natives results in improved biodiversity outcomes, with higher richness and abundance of plants, birds and invertebrates, which not only make all of this possible, but also make the system sustainable. This means that landowners can cut costs in the long run by working with nature, using its natural characteristics and processes to their advantage.

In any case, growing a forest on a farm is not an overnight process

It requires a lot of patience, but those who are able to encourage native regrowth are safeguarding the country’s biodiversity and resources for all of us, and contributing to our sustainability. Native forests hold a much more strategic long-term position in the bid to plant more trees, and hill country farmers are the most well-placed to allow their regeneration.

Perhaps one day we will have the privilege of living and working alongside the lush and bustling forests that once supported us, as we learn to support them.

Mature beech forest (own photo).

This article was prepared by Master of Science student Sarah Gabites as part of the ECOL608 Research Methods in Ecology course.

Based on the article by Pedley, D., McWilliam, W. and Doscher, C. (2023). Forests from the grass: natural regeneration of woody vegetation in temperate marginal hill farmland under minimum interference management. Restoration Ecology 31:3. https://doi.org/10.1111/rec.13852

September 1, 2025
What went wrong with Himalayan tahrs in New Zealand?

How would you feel if an animal deeply respected and protected in your homeland was treated as a trophy animal and hunted in another country for being invasive? I was heartbroken to discover the fate of Himalayan tahrs when I first arrived here in New Zealand.

A proud Sherpa with Chhomolungma (Mt. Everest) in the background (Hey! He looks exactly like the author of this blog!!!) Photo: ©Author

Being from a native Sherpa community in the Khumbu region (popularly known to the world as The Everest region), I grew up roaming around the high alpine environment of the Himalayas. The region lies in the Sagarmatha National Park and Buffer Zone (SNPBZ) and is home to majestic mountains including the highest peak in the world, Khangri Chhomolungma (Mt. Everest in English), as well as stunning rugged terrains, glaciers, lakes and diverse flora and fauna.

A photo of male Himalayan Tahr taken on the way to Everest base camp trail Photo: ©Author

The Khumbu region is habitat to many endangered wild animals including snow leopards, musk deer and red pandas. Due to its rugged environment and mountain slopes, the region is also a suitable native habitat of the Himalayan tahr (Hamitragus jemlahicus). We call them “Ri Rau” in Sherpa language meaning “Wild Goat”.

A herd of Himalayan Tahr seen on the way to Everest Base Camp Trail Photo: ©Author

I was around 6-7 years old when I first saw a herd of the Himalayan tahrs grazing on the hills near my hometown Lukla while walking with my father. I remember watching and admiring them for hours hiding behind a rock. I was immediately mesmerized by their presence. The male stood out with their glossy thick brown coat of straight hair as if they came straight out of a salon, with strong dark horns surrounded by the females and their young ones. I was especially stunned by their ability to move confidently and swiftly across the rocky slopes. That moment still relives fresh in my memory. Since then, whenever I saw them, I always paused for a moment to admire their elegance and capturing the moments for memories.

The Himalayan tahr is currently listed as Near threatened on the IUCN Red list. In their native habitat they are mostly predated by common leopards and snow leopards. Due to anthropogenic activities such as habitat loss and illegal poaching, their population have been declining, and they are now protected in their native Himalayan environments.

When I first arrived in New Zealand, I discovered that the Himalayan tahrs are considered as invasive species, and they are hunted for recreational purpose in the country. I was really surprised by this as they are protected in the region that I come from. After doing some digging, I found out that the Himalayan tahrs were introduced in New Zealand in the early days of European settlements for sport, gifted by Duke of Bedford to help with recreational hunting option for emigrating Englishmen and released near the Hermitage at Mt Cook in 1909. As New Zealand doesn’t have any natural predators of Himalayan Tahrs, their population escalated rapidly reaching a population size of tens of thousands over the Southern Alps.

A Trophy Hunted Tahr
Photo: Image generated by ChatGPT (DALL-e) by OpenAI

The Department of Conservation of New Zealand (DOC) has been working on Himalayan Tahr population control since 1993 under the Himalayan Tahr Control Plan (DOC, 1993: HTCP) which allows limited population of around 10,000 tahrs within the seven defined management units. However, the tahr population has grown beyond the limitation of management plan in recent years, making it difficult to control them. The HTCP also includes a defined feral range to contain their population and permits farming or holding in game estates for commercial hunting only within the designated range.

A report from Lincoln University, conducted in 2020 by Geoff Kerr, Garry Ottmann and Fraser Cunningham studied the potential for containing tahrs in game estates outside their feral range to reduce demand on the wild tahr resource as recommended by the Game Animal Council (GAC, 2014). Three GPS tracked male tahrs were released in the High Peak Game Estate on 19th December 2018 to monitor their behavior and movement pattern inside the enclosure over a twelve-month period. While one tahr died of unknown causes, the remaining two were kept there until 24th December 2019. The study was done on the hypothesis that tahr containment within a game estate outside of their feral range would be successful.

The trial was successful showing that Himalayan thar can be effectively contained in game estates outside their feral range. GPS data showed minimal fence interaction, and the tahrs quickly adapted to their new territory. Most boundary activity occurred during the breeding season. The study also suggested potential for larger scale commercial operations due to their herding behaviour.

Despite extensive research and ongoing control efforts, Himalayan tahr continues to threaten New Zealand’s native biodiversity by heavily grazing on tussocks, alpine herbs, and shrubs, plants that have no evolutionary history of mammalian herbivory, thereby disrupting the natural ecological balance.

This problem also raises a serious question of human intervention with nature. More than wondering how to manage tahr populations, I find myself asking: What are they even doing here in the first place? Himalayan tahr has become invasive in New Zealand because people introduced them here without realizing its future consequences and it has backfired us, leaving us to manage the aftermath of our own decisions.

Witnessing the realities of a Himalayan tahr changing from a revered mountain dweller in my homeland to trophy hunted invasive species in New Zealand, has been an emotional and eye-opening experience for me. Looking at the conservation dilemma of tahrs between two different countries has challenged my perception and shown how the value of wildlife depends on the context. The Himalayan tahr’s journey, much like my own, has crossed oceans and adapted well into the new environment but the only difference is that the tahrs didn’t choose to come here. The Himalayan tahr’s story is a very powerful reminder of how human actions can disrupt the natural ecosystem. As someone who grew up admiring their beauty in the Himalayas, I hope their fate improves in the future.

The author, Ngima Chhiri Sherpa, is a postgraduate student in the Master of Applied Science (Environmental Management) at Te Whare Wānaka o Aoraki Lincoln University. This article was written as an assessment for ECOL 608 Research Methods in Ecology.

Paper Reference: Kerr, G. N. ., Ottmann, Garry., & Cunningham, Fraser. (2020). Himalayan tahr on game estates outside the tahr feral range. Centre for Land, Environment & People, Lincoln University. https://digitalnz.org/records/44715317

August 27, 2025
Kiwi Hedgehogs : A Journey of Curiosity and Connection

Curiosity often starts with a sense of wonder and a desire to understand the world around us. If you are a parent, I hope you have noticed and observed this in your children. Their endless questions and fascination with the world are a beautiful reminder of the joy and excitement that comes with learning and discovery.

I have four lovely daughters, among them four-year-old Arshifa Gul is a bundle of curiosity and always gives me a tough time replying to all her unexpected questions. She also loves watching animated movies, stories and travelling. Back in 2023, I took her to the Pakistan Museum of Natural History for the first time. She was shocked by seeing the animal models and skeleton structures, especially the huge dinosaurs and their roaring, Asiatic lions and their growling, and the realistic models of sharks and dolphins. At first, she was quiet, observing closely, making sure they couldn’t attack. Then, her surprising questions began. “Why is the dolphin here? Who made the dinosaur roar? How did they get so big? When did they live?”

As a wildlife biologist, I’ve worked with animals for years, but her questions confused me! It was the first time that I struggled to explain my own field. Her curiosity pushed me to think deeper and find ways to explain complex concepts in simple terms. Our trip ended but Arshifa Gul’s questions did not. Her curiosity shifted to linking the roars and growls to the human voice of the animals she heard in the animated movies

AI-generated image (Grok) of Arshifa Gul standing in awe before a towering dinosaur skeleton in a museum, her eyes wide with wonder, surrounded by animal models like lions and dolphins.

The next morning at breakfast, Arshifa Gul excitedly shared her thoughts about the characters from her favourite animated movie, “Allahyar and the Legend of Markhor”, set in Pakistan. She talked about the boy Allahyar and his animal friends, then asked where these animals lived, how big they were in real life, what their calls sounded like, and if we could visit them. I said yes we could, but explained that Khunjerab National Park, home to the markhor and snow leopard, was seven hours away.

Landscape of Khunjrab National Park, Pakistan © Nisar Ahmed

Her curiosity turned our breakfast into an adventure planning session. I gathered information on the park’s history, species like snow leopards, ibex, and Marco Polo sheep, and conservation efforts, including a trophy hunting program initiated by IUCN and WWF. 80% of the total benefits from this hunting initiative goes to the local communities while the remaining 20% is invested in habitat protection and improvement.

We visited the site, and she enjoyed the trip thoroughly and I answered most of her questions and her confusion cleared regarding voices and the original habitat of different species. Answering her is always tough, but it makes me see the world through her bright, wondering eyes, full of love for animals. She makes me realise how important it is to nurture this curiosity, not just in her, but in all children.

Curiosity is a powerful force that drives us to explore, learn, and grow. Arshifa Gul’s curiosity inspired me to write about the introduction of European hedgehogs into New Zealand. The European hedgehog, also known as the West European hedgehog, is a charming little creature native to Europe.

Hedgehogs can live in a variety of terrestrial habitats and are mostly active at night. They have a slow, hesitant way of walking and often stop to sniff the air. Unlike other hedgehog species that

Hedgehogs have fascinated people for centuries. Their spiky charm has made them popular in history, from ancient amulets to modern pop culture icons, like Sonic the Hedgehog. Did you know that New Zealand is the only country outside Europe where European hedgehogs have successfully been established in the wild? This fascinating story of how these spiky little creatures made their way to both the North and South Islands of New Zealand is filled with twists and turns.

Back in the 1869, acclimatisation societies in New Zealand introduced European hedgehogs to control pests. For a long time, it was believed that hedgehogs were first introduced to the South Island and later spread to the North Island. However, a molecular study in 2013 challenged this view and suggested that hedgehogs were independently introduced to both the islands directly from Europe. This means that the North Island had its own separate introduction of hedgehogs, rather than receiving them from the South Island.

To uncover the truth, researchers from various universities, including Lincoln University, turned to historical records, especially old newspaper articles. They discovered that there were at least four independent shipments of hedgehogs into the North Island before 1900 (which were not documented in the first publication back in 1975). These findings confirmed that the North Island’s hedgehog population did not originate from the South Island. This study highlights the importance of combining observational data, molecular studies, and historical records to understand the introduction pathways of species.

Hedgehog searching for food © Author

The European hedgehog population thrived well in NZ, too well, as it has now become problematic for native wildlife. For example, they prey on ground-nesting birds and compete with native species for food. Leading conservationists have classified them as a pest, and the Department of Conservation New Zealand has launched a campaign to protect native species from hedgehogs.

Arshifa Gul’s questions and the hedgehog share a common thread. Curiosity drives us to explore and learn. Whether it’s a child marvelling at a museum exhibit or scientists unravelling ecological puzzles, curiosity bridges wonder and action. It reminds us that conservation isn’t just about saving species—it’s about nurturing the spark that makes us care. As parents, educators, or stewards of the planet, or a teacher we can foster curiosity by encouraging, sharing stories, and exploring nature together by using interactive technologies.

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

Reference: Pipek, P., Pysek, P., Bacher, S., Cerna Bolfikova, B., & Hulme, P. E. (2020). Independent introductions of hedgehogs to the North and South Island of New Zealand. New Zealand Journal of Ecology, 44(1), 3396. https://doi.org/10.20417/nzjecol.44.7

August 22, 2025
Never ask a lizard its age (Calculate it using science!)

Where were you during the 1969 moon landing? What about at the turn of the century when the world was bracing for the Y2K Apocalypse? Or during the 2020 Covid-19 pandemic?

What if I told you that there are world record-breaking geckos in Canterbury that were here through it all? That two geckos in particular, ‘Antoinette’ and ‘Brucie-Baby’, recently celebrated their 60th and 64th birthdays? That might seem unimpressive compared to a human lifespan, but most geckos are lucky to live 10-15 years elsewhere in the world.

So, what’s their secret? And how do we know this? It’s not like you can just ask a gecko its age (that would be rude! as well as difficult…). If you’ve worked with geckos or other lizards like I have, you’d also know that they’re elusive at the best of times and all look the same to an untrained eye. Well, like all great scientific breakthroughs, this story involves good record keeping, a bit of fancy maths, and, of course, Lincoln ecologists!

Antoinette and Brucie-Baby, the world’s oldest Waitaha geckos (Woodworthia brunnea). Image: Allanah Purdie | Department of Conservation 2025 (CC BY 4.0)

The Beginning

Let me take you back to the summer of ‘67. Staff from the Department of Scientific and Industrial Research (DSIR) are tramping across Motunau Island, which lies 64 km north of Ōtautahi Christchurch and 1 km off the Canterbury coast. Weeds, fire, and rabbits had drastically changed the island’s vegetation since the 1850s, but rabbits were eradicated in 1962 and Motunau had otherwise never seen an introduced mammal. That absence makes the island a decent refuge for native lizards and seabirds.

Under the leadership of ecologist, Tony Whitaker, a team of DSIR staff surveyed lizards there every summer until 1975. As part of this, they caught Waitaha Geckos (Woodworthia brunnea) along a 20 x 20 m grid using pitfall traps, which are essentially baited holes in the ground that lizards fall into trying to get a sweet treat (don’t worry , this doesn’t harm them!).

Motunau Island in Canterbury, New Zealand. Image: Wikimedia Maps n.d. (CC BY-SA 4.0)

Back then, Whitaker’s surveys had two main goals. The first was to test what kind of bait the lizards liked the most and the second was to figure out how to find nocturnal geckos in the dark. In case you were wondering, they found that lizards LOVE canned pear and that you can find geckos at night by spotlighting because their eyes reflect light like cats. For this story, though, the basic measurements taken from individual geckos over the years turned out to be far more interesting…

An Exciting Realisation

Fast forward several decades to the late 1990s and enter our Lincoln ecologists: Masters student Carol Bannock and Senior Lecturer Graham Hickling! Together with Tony Whitaker himself, they were going through Whitaker’s notes and realised that because geckos caught in the 1967-75 DSIR surveys were permanently marked by a unique combination of toes being clipped, they may be able to identify some of the same individuals 30 years later*. They also realised that because each individual had its snout-vent length (SVL) recorded, they could use growth rates to figure out how old each gecko was when first captured.

* Side note: I know toe clipping sounds brutal. We’ll unpack that later… For now, understand that although this method of identifying individuals is not used anymore, it was the best method for ecologists at the time because lizards shed their skin and therefore can’t be permanently marked by things like paint or dye.

Measuring the SVL of a Waitaha Gecko (Woodworthia brunnea) in Akaroa, Canterbury. Image: Alice McCormick 2024 (used with permission)

With no time to lose, the trio raced back to Motunau! With some searching, they found the original lizard grid from old survey pegs (who needs modern GPS?) and diligently caught and measured geckos between December 1996 and February 1997. Overall, they found 61 new geckos and recaptured 16 of the 133 toe-clipped between 1967-1975 (~12%).

To determine the growth rates of Motunau’s Waitaha Geckos, Bannock, Whitaker, and Hickling used the average SVL of one-year-old geckos caught in 1996-97 (identified by their small size) and the differences in SVL length for geckos caught 12 months apart in 1967-75 to create a growth curve. They then used that curve to estimate how old each gecko was when first caught in 1967-1975 (large geckos were categorised as 6+ years because Waitaha Geckos tend to stop growing after this). Next, they calculated the age of the 16 geckos recaptured in 1996-97 by adding their estimated ages to the number of years since first capture. The modelling for this is a little tricky, but it’s thoroughly explained in this paper by Ebert (1980), if you are interested. What you really need to know is that 10 of those 16 geckos turned out to be at least 36 years old!! The remaining 6 were between 29 and 34.

2025 and Beyond

In 1999 when Bannock, Whitaker, and Hickling published their paper, finding 30+ year-old geckos was huge news. It proved that Waitaha Geckos on predator-free Motunau could live equally as long in the wild as they do in captivity and added at least 15 years to the previously estimated maximum age for the species (or any gecko species in the world for that matter!).

The discovery was so exciting that it also prompted the Department of Conservation to immediately take charge of regular surveys on Motunau. In fact, it was in their most recent 2024-25 survey that ‘Antoinette’ and ‘Brucie-Baby’ were rediscovered (named in honour of Tony Whitaker and his co-worker, Bruce Thomas, in 1967 and 1969).

Iris pattern of a Waitaha Gecko (Woodworthia brunnea), annotated in I_³S Pattern. The three reference points (blue) and outlined identification area (green) were manually selected to allow I₃S to generate and compare key points (red) with other annotated photos. Image: © Samantha Dryden 2025.

That is not the end of Lincoln’s gecko searching though! Since 2021, our very own Dr Jennifer Gillette has been testing photography as a technique to identify individuals and to, hopefully, replace toe clipping in long-term studies. Together with her summer students, she has taken 1000s of photos of Waitaha Gecko iris and dorsal patterns around Akaroa Harbour and tested the ability of a pattern-recognition software called I³S to correctly match new photos with existing individuals in her database.

Dorsal pattern of a Waitaha Gecko (Woodworthia brunnea), annotated in I_³S Pattern. The three reference points (blue) and outlined identification area (green) were manually selected to allow I₃S to generate and compare key points (red) with other annotated photos. Image: © Samantha Dryden 2025.

According to Jennifer, the research on Motunau’s geckos has significantly impacted the way we understand and manage gecko populations in Aotearoa today. Because they live so long, Waitaha Geckos have evolved to be K-selected species, which means they mature slowly and have very few offspring. This strategy worked well before humans arrived, but today, most gecko populations in Aotearoa don’t have the luxury of living on predator-free islands like Motunau. This means that many geckos may be eaten before they are old enough to have babies, and their populations may take decades to recover from predation.

That is why being able to identify individuals like Antoinette and Brucie-Baby is so important! It’s also why no pest species can be overlooked in conservation and environmental management efforts!!

Lincoln University senior tutor, Jennifer Gillette (second from the right) and her students monitoring Waitaha Geckos (Woodworthia brunnea) around Akaroa Harbour, Canterbury. Image: © Samantha Dryden 2024.

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

Article reference: Bannock, C. A., Whitaker, A. H., & Hickling, G. J. (1999). Extreme longevity of the common gecko (Hoplodactylus maculatus) on Motunau Island, Canterbury, New Zealand. New Zealand Journal of Ecology, 23(1), 101-103.

August 18, 2025
A Knobbly Future?

The Story of the Canterbury Knobbled Weevil

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Links/References

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

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

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

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

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

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

August 12, 2025
Tips for wildlife paparazzi
How camera angles reveal the secret lives of elusive predators

On my first visit to New Zealand, I was amused to see fellow backpackers flipping through glossy magazines filled with paparazzi shots of A-listers. I remember thinking, what a strange profession, hiding in the bushes to snap a shot of someone and follow their day-to-day routes.

Fast forward a couple of decades and here I am, fascinated by research articles on the optimal camera angle to capture elusive creatures. Turns out, the world of conservation has its own paparazzi. Moreover, I feel everyone should know their tricks!

When it comes to elusive predators, capturing them in their tracks is more than a curiosity, it’s a conservation tool. Camera traps are effective in estimating animal densities, before and after control even in the most adverse habitats, like wetlands.

CC BY-NC-SA 2.0 Image by Gábor

The A-listers in this article are elusive foreign predators, feral cats and mustelids (stoats, ferrets and weasels), always on the move and few and far between, like true celebrities. The red carpet is the New Zealand bush – an exclusive venue lined with a crowd of endemic icons watching in fear as the foreign stars steal the spotlight. The photographers? Not screaming paparazzi, but silent, motion-triggered camera traps, stationed like field agents waiting for a predator in sight.

But here’s the million-dollar question: Does the camera angle make or break the shot?

Just like in Hollywood, where a low angle shot can flatter or fail, the positioning of a trail camera can dramatically influence what gets captured in the frame. Nichols et al. (2016) asked exactly that: Should camera traps aimed at cryptic predators, like feral cats and mustelids, be set up horizontally or vertically for the best results?

The red carpet

Conducted in the pastoral Toronui Station, Hawke’s Bay, the researchers placed 20 pairs of camera traps—each pair with one camera horizontally and the other vertically. A horizontal camera faces forward at animal eye level. A vertical camera looks downward, much like a security camera.

To increase the chances of a sighting, the cameras were positioned at the ecotones or edges of forest fragments where possible.

To lure the stars, they used bait: not truffles, caviar or fur coats but rabbit meat and ferret-scented bedding. The cameras were left running for two months, waiting for their moment to shine.

Setup of horizontal and vertical cameras, Toronui Station, New Zealand, in 2014. Photo Nichols et al. 2016

The Scoop: Horizontal lands the money shot

When the footage was reviewed, the results were clear:
- Horizontal cameras recorded about 1.5 times more images of the target predators than vertical ones.
- They also captured significantly more independent encounters—meaning more unique visits, not just a burst of shots from one animal loving the spotlight.
- Total photos (including non-target species) were also higher with horizontal setups.
- False triggers (empty shots) were similar between both orientations.
In short, if you’re trying to catch a predator in the act, horizontal cameras are your go-to paparazzi.

But vertical isn’t out of the picture

Interestingly, vertical cameras had an unexpected benefit: image clarity. Because they face straight down, they often captured finer detail—like coat patterns on cats. This could be important when trying to identify individual animals, for tracking their movements or population size estimates based on mark–recapture.

CC BY-NC 2.0 Image by Kari Nousiainen

However, there’s a catch. Cats are big. The narrow vertical field of view meant that 63% of cat photos taken from above only caught part of the animal.

Tips for conservation’s paparazzi

This study is more than a technological tweak. It is a lesson in field strategy. For conservationists using camera traps to monitor invasive species, the setup matters:
- Horizontal orientation is best for maximizing detection rates.
- Vertical orientation may still be helpful for species or individual identification, if the field of view can be adjusted.
And crucially, the orientation didn’t affect the rate of false triggers, so there’s no trade-off there.

Final frame

Whether you’re tailing Taylor Swift in LA or tracking a mustelid in the New Zealand bush, one thing is clear:

It’s all about the angle.

For conservation science, that angle could mean the difference between missing a species or getting the data needed to protect native wildlife. For our most wanted A-listers the red carpet might be made of forest floor, but the flash of a camera still tells a powerful story.

This article was prepared by Postgraduate Diploma in Applied Science student Ine Schils as part of the ECOL608 Research Methods in Ecology course in the Department of Pest-Management and Conservation.

Reference

Nichols, M., Glen, A. S., Garvey, P., & Ross, J. (2017). A comparison of horizontal versus vertical camera placement to detect feral cats and mustelids. New Zealand Journal of Ecology, 41(1), 145–150.
August 7, 2025
New Zealand’s most stubborn weed

Cirsium arvense is commonly known as the Canada thistle in USA and Californian thistle in Canada. No one wants to take responsibility for these prickly things. They actually come from Europe where they are called creeping thistles.

This thistle is a small weedy plant that can be a potential nightmare for New Zealand farmers. According to the NZ Ministry for Primary Industries, (2021), it cost the country $722 million in lost revenue in the year 2020 alone, up from $31 million in 2009.

^{Photo by Make It Old (Flickr User)}

Given the disruptive nature of this weed, Wendy Kentjens, a budding weed ecologist with the passion for gardening, along with her supervisors, Seona Casonato and Clive Kaiser, decided to learn more about controlling the Californian thistle population on New Zealand pastures.

To understand why Californian thistles are so weedy, Wendy decided to study the interesting microscopic world of the endophytes living inside, and how they may help or hinder the plant.

Sounds straight forward! Well, it was far from that.

Here is a summary of the challenges Wendy faced while carrying out research on Californian thistles.

‘Ah the prickly little devils…’ – Working with the thistles meant cuts and scratches all through the research.

‘Miss Unpopular, conducting pot trials at the nursery.’ – Turns out, planting weeds that no one likes is a fast way to make some frenemies.

‘The sheep ate my data!’ – Wendy found that the sheep initially didn’t eat thistles on pastures, but when they got infected with a rust fungus (Puccinia punctiformis), it made it very tasty for the sheep. She talks more about using rust fungas as a biocontrol agent in her paper “Californian thistle (Cirsium arvense):endophytes and Puccinia punctiformis” (Kentjens et al., 2024).

‘Hard to photograph the entire plant.’ – It can be really hard to see all the features of a plant from a single photo; Wendy’s mum made her a pencil drawing of the weed for her thesis.

^{Figure drawn by Marion van Cruchten}

How do you find the microscopic endophytes within the thistle?

To find all the endophytes present in these thistles, the bottom, the middle, and the top leaf of the plant were all cut into small 5 mm² pieces and placed in a petri dish over a growing medium. Then, spore by spore, each different looking fungus was isolated into new growing dishes and incubated.

Voila! Now Wendy had pure cultures of all the fungi she had found and was all ready for the next step.

DNA from these pure fungal cultures was collected and identified.

What did they find inside?

A total of 88 genera of fungi were cultured from the plant tissue, of which 65 were not previously associated with Californian Thistles.

The diversity found was a significant increase in our understanding of this infamous weed and what lives within its structure that makes it supposedly invincible.

Fungal biocontrol can be an effective tool against these weeds. However, Endophytes can alter outcomes of a host–pathogen interaction. A recent study published by Manaaki Whenua (Landcare Research), found that 60% of all rust fungus released as biocontrol had a medium effect on the weed host or a variable effect. Around 15% of all rusts released as biocontrols have failed to become established at all.

There could be a number of reasons for the variable or unsucessful results. In the case of the invasive Japanese knotweed (Fallopia japonica), two of the endophytes accociated with the weed (Alternaria sp. and Phoma sp.) hindered the establishment of fungal biocontrol by suppressing the production of rust pustules (raised masses of coloured spores that rupture epidermal leaf tissue). (Den Breeyen et al., 2022).

Understanding these organisms living within the thistle will help future studies on the effective use of fungal biocontrol in fighting these “lovely” weeds. Looking at the endophytes and how they are helping these weed propogate so sucessfully will help us get one step ahead of it and hopefully find biocontrol agents that can circumnavigate these endophyte-host relationships.

_{Note that the figure drawn by Marion van Cruchten is currently under review by the European Journal of Plant Pathology titled ENDOPHYTIC DIVERSITY AND COMMUNITY COMPOSITION OF CIRSIUM ARVENSE TISSUES OVER A GROWING SEASON. Authors Wendy Kentjens, Seona Casonato, and Clive Kaiser}

This article was prepared by Master of Science student Dee Patel as part of the ECOL608 Research Methods in Ecology course.

References:

Den Breeyen, A., Lange, C., & Fowler, S. V. (2022). Plant pathogens as introduced weed biological control agents: Could antagonistic fungi be important factors determining agent success or failure? In Frontiers in Fungal Biology (Vol. 3). Frontiers Media S.A. https://doi.org/10.3389/ffunb.2022.959753

Kentjens, W., Casonato, S., & Kaiser, C. (2024). Californian thistle (Cirsium arvense): endophytes and Puccinia punctiformis. In Pest Management Science (Vol. 80, Issue 1, pp. 115–121). John Wiley and Sons Ltd. https://doi.org/10.1002/ps.7387

Kentjens, W., Casonato, S., & Kaiser, C. (2024). Endophytic genera in californian thistle (Cirsium arvense (L.) Scop.). Australasian Plant Pathology, 53(2), 199–210. https://doi.org/10.1007/s13313-024-00972-w

Ministry for Primary Industries. (2021). Economic costs of pests to New Zealand (Nimmo-Bell & Associates, Ed.; Paper No: 2021/29). Ministry for Primary Industries. https://www.mpi.govt.nz/dmsdocument/48496-Economic-costs-of-pests-to-New-Zealand-Technical-report

_{– figure drawn by Marion van Cruchten is currently under review by the European Journal of Plant Pathology titled ENDOPHYTIC DIVERSITY AND COMMUNITY COMPOSITION OF CIRSIUM ARVENSE TISSUES OVER A GROWING SEASON. Authors Wendy Kentjens, Seona Casonato, and Clive Kaiser}

August 5, 2025
Under Cover of Darkness: Moon Brightness and Mammalian Predator Activity

Written by Kate McDowell

Last June, I found myself several hours into what would end up being a sixteen-hour run, in the middle of the night, on the coldest weekend of the year. As the ground visibly started to freeze in front of me, I realised that my head torch was struggling in the negative temperatures. Its battery couldn’t cope with the cold exposure. But you know what, I had a trick up my sleeve; it was a full moon.

I was guided by the incredible illumination of the moon on a clear winter night, and by how few animals I saw apart from the sheep and cattle of Lake Taylor station. As I left the station and entered Lake Sumner Forest Park, my headtorch flickered in the biting sub-zero temps of mid-winter New Zealand near the Southern Alps. I had barely heard a sound since nightfall, apart from my own crunching footfalls on freshly frozen tussock.

There were no pest animals dancing in the moonlight that chilly midwinter run, and I found myself wondering if our mammalian pests changed their activity based on how bright that big ball of cheese in the sky was. In 2016, Shannon Gilmore did a neat study on the effects of moon phase and illumination on activity of five introduced NZ mammals (cats, rats, mustelids, possums, hedgehogs) for her thesis at Lincoln University.

A trail runner foolishly runs 16 hours over an alpine pass, whilst being watched by introduced predators who may or may not be contemplating consuming the body of said runner. [Source: Chat GPT AI, Kate McDowell]

I seemed to be one of the few introduced mammals blatantly puffing my way up the North Branch Hurunui riverbed. I have this strong memory of looking down and watching myself be followed by my own moon shadow. It made me question – how many eyes were following me in the dark canopy of the nearby beech forest?

Gilmore found that increased vegetation cover and rain were contributing factors to pest detection. Sites with dense canopies had higher detection rates, potentially because they provide better shelter and reduced exposure from threats like light. While rainfall was not a statistically significant factor, pest activity generally decreased with rainfall. Gilmore suggested this may be because it is cold or the rain might be disrupting the animal’s sense of smell.

So maybe my paranoia about forest animals staring me down wasn’t so crazy after all. It was certainly interesting to think back on the run and how many introduced predators there could have been in the nearby beech forests. The conservation implications for understanding where predators are and why they might change their activities also gave me some things to mull over the next day.

Detecting these introduced predators is essential for informing control efforts; we need to know where predators are and how many of them are in a given area. Environmental conditions may be obscuring the predator’s true activity levels. Gilmore added to previous studies of moon phase effects on mammals by accounting for interaction effects of weather and vegetation. Whether these effects were caused by the lower light levels or by something else not explored in this study is yet to be answered.

Many studies have looked at the role of moon phase and animal activity, but in 2016 few studies had investigated the additional factor of the moon’s brightness. Gilmore was the first to measure hourly light levels through the night and looked at how it affected the activity level of the nocturnal pest species. A highly sensitive light meter (Sky Quality Meter, or SQM) to measure illumination levels between moon phases in the Blue Mountains (Otago), Banks Peninsula (Canterbury) and Hawkes Bay.

Gilmore found that while moon phase could not explain pest activity, moon illumination did. As the dark side of the moon grew larger, pests seemed to thrive under cover of darkness and became far more active. When the moon hits a mammal’s eyes, Gilmore theorised that they may be spurred to hide. Most introduced mammals in NZ are prey in their native countries and it is hard to say whether a single century of living without their native predators has changed their behaviour.

SQM successfully managed to detect differences in illumination between moon phases and under different canopy cover levels. Canopy cover was found to have a larger impact on illumination than moon phase. SQM findings on Banks Peninsula suggested that on darker nights a pest is more likely to be active.

Building on earlier research, Farnworth, Innes and Waas (2016) released a paper looking at the effect of light on mouse foraging behaviour. This study agreed with Gilmore’s results, finding that mice displayed strong preferences for foraging in unlit areas. Farnworth et al. further built on Gilmore’s conclusions by contemplating that artificial light could provide protection from predators in ecologically sensitive areas – for instance, in areas where predator proof fences have been breached by a tree limb dropping on it.

Predator proof fence study by ZIP scientists showing a rat trying to escape. [Source: ZIP (Zero Invasive Predators Ltd), used with permission]

The innovative organisation Zero Invasive Predators (ZIP) completed an interesting follow up study in 2018, focusing on whether or not light could deter rats from entering an area. They found that although light did not limit rats passing through, they were less likely to linger in lit zones. Their conclusion: illumination could be used in a layered deterrent system, where light is used to slow down pests.

Conservation in NZ is generally hamstrung by lack of funding. Efficiency is key to making the most of the meagre dollars on offer, so studies like Gilmore’s can help optimise monitoring and control operations. So when that bad moon comes a-rising, you can bet that pest control and monitoring will be less effective, and it would be more useful to focus efforts during darker nights.

I definitely felt exposed running through a riverbed under a full moon, so I can appreciate how light can serve as a useful predator deterrent. It’s another tool we should add to the belt as we work toward a predator-free country.

We’ve reached the end of our illuminating lunar article, but the real question now is how many song references did you pick up on? 😉

This article was prepared by Master of Science student Kate Morrison as part of the ECOL608 Research Methods in Ecology course.

Paper: Gilmore, S. (2016). The influence of illumination and moon phase on activity levels of nocturnal mammalian pests in New Zealand (Master’s thesis, Lincoln University).

July 21, 2025
The Magical World of Grass and Clover

*Disclaimer: This article contains Harry Potter references

After four years of living and studying together, you would think you know someone pretty well. Alas, last week it turned out one of my flat mates had never seen (or read) Harry Potter… shocked, heartbroken, and outraged – the only way to solve this flat feud was to start from the beginning and watch Harry Potter and the Philosopher’s Stone.

The next day, it was back to study. However, I couldn’t get the wizarding world out of my mind, especially knowing that the second movie, the Chamber of Secrets, was scheduled for that night. It got me thinking. Every hero has a sidekick. Batman and Robin, Frodo and Sam, Harry and Ron. But what if these iconic heroes don’t only exist in the worlds of Gotham City, Middle-earth, or Hogwarts. What if the heroes on this earth have sidekicks too?

Legumes (like clovers) are heroes. Destined for greatness and capable of incredible things, they can capture nitrogen (N) from the atmosphere and convert it into ammonia, a biological form of nitrogen that fuels the ecosystem. Farmers often incorporate clovers into their pastures to provide nitrogen into the system. Because of their magic-like nitrogen capturing abilities, clovers boost the growth of neighbouring grasses and create an increase in food quality and quantity for grazing animals.

White Clover (Trifolium repens). CC BY 2.0. Harry Rose

It is generally understood that this is a one-way relationship, meaning clovers are humble heroes that provide N to the grasses and plants surrounding them. However, through my muggle research, I came across a recent study titled “Grasses procure key soil nutrients for clovers” by PhD student Zhang Wei.

Could it be? A sidekick to our green three-leaf (sometimes four if you’re lucky) hero?

Wei and his team questioned whether we properly understand the relationship between clovers and grasses. For the purpose of this article, let’s think of clovers and grasses as characters to understand better their relationship and how they work together.

Perennial Ryegrass (Lolium perenne). CC BY-SA 4.0. Michel Langeveld

Different plant species have various magic-like abilities to acquire nutrients. Grasses, for example, are potion makers and can release chemical substances into the soil to make elements such as iron (Fe), zinc (Zn), copper (Cu), and manganese(Mn) more available in the soil. Other plants call on the Room of Requirement and collaborate with fungi to increase access to nutrients through the fungal networks. Like how the Room of Requirement appears for those who need it most, fungi create symbiotic relationships with plants, enabling more nutrients to ‘appear’ and become more accessible in the soil. And clovers, as you now know, use their spellwork to fix atmospheric nitrogen (N).

However, just like the spell “Wing-gar-dium Levi-o-sa” requires a certain pronunciation, N fixation requires a certain nutrient – phosphorus. Phosphorus is a nutrient constantly in high demand for clovers due to N fixation being such a taxing process.

Zhang Wei and his research team carried out experiments to better understand how grasses influence the nutrient availability for clovers. Clovers and grasses were grown separately in individual pots, much like Harry living alone in the cupboard under the stairs. They were also grown together in shared pots, similar to Harry and Ron bunking together at Hogwarts. Measurements were then taken from the soil and leaves in all the pots to understand how the clovers and grasses influence each other’s growth.

The researchers found that grasses promoted the growth of clovers when grown together. This was evident when higher amounts of nutrients such as nitrogen (N), phosphorus (P), potassium (K), and sulphur (S) were found in clover leaves growing with grasses compared to clovers that grew alone. Grasses give clovers a boost in accessing essential nutrients, much like how Ron supports Harry, offering the strength and loyalty he needs to face He-Who-Must-Not-Be-Named.

Mixed sward of White Clover (Trifolium repens) and pasture grasses growing together. Nicole Parnell. 2025.

Additionally, more biomass was achieved when both clovers and grasses were grown together compared to when they were grown apart. How would Harry have gotten through his years at Hogwarts without his friends by his side? They achieve more when they work together. By sharing their resources, the plants could increase their biomass, which boosts livestock feed while lowering fertiliser demand.

The muggle authors acknowledge that more research is needed to fully understand the complexities of how nutrients move through the soil in plant communities like this, especially under field conditions. In 2023, Zhang Wei and his supervisors took the study into the field and, once again, saw enhanced legume growth when grown alongside a diverse range of pasture grass species. Think of Harry’s resilience and leadership, Ron’s loyalty and humour, and Hermione’s intelligence and discipline, all of which work together to create a strong, unbeatable partnership. Similarly, there is an enhancement of nutrient uptake in diverse pastures with legumes (including native legumes) and grasses. This suggests a possible reduction in fertiliser requirements in pastures with increased plant diversity.

A study that referenced Zhang Wei’s work similarly found that plant mixtures with various legume and grass species reduced intraspecific competition, a term that explains competition between individuals of the same species (think Gryffindor vs Slytherin). This means that the growth and productivity of both legumes and grasses were further enhanced when grown together.

Zhang Wei’s PhD study provided further insights into the flow of nutrients within plant communities, demonstrating that grasses also play a vital role in nutrient availability and enhancement. This study builds on the argument that pasture diversity can reduce reliance on artificial fertilisers and promote sustainable farming methods. These methods can increase the ecosystem’s stability, making it more resilient to disturbances such as droughts and/or floods. Like any partnership, growing together makes them stronger.

That’s where the magic happens.

This article was prepared by Master of Science student Nicole Parnell as part of the ECOL608 Research Methods in Ecology course.

July 10, 2025