EcoLincNZ

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

    Spiders.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  • Dirty little secrets or tiny heroes of the soil world?

    Dirt was one of my first friends. My earliest days were spent collecting worms from the backyard and trying to convince my parents I hadn’t done any dirt taste testing that day (I probably had, but for purely scientific reasons). I was fascinated by what seemed like an entirely different world in the soil of my parent’s garden. I could find all kinds of goodies from insects to plant roots.

    At university I was introduced to the truly magical world in soil: microbes. Although not visible to the naked eye, the tiny worlds inhabited by fungi, bacteria, viruses, and other unbelievably small things, should not be overlooked. These tiny worlds are called the microbial community and they have important roles in New Zealand forests.

    Photo of soil microbes under a microscope. Photo by Pacific Northwest National Laboratory (CC-BY-NC-SA 2.0)

    A good place to start thinking about microbial communities is our own bodies. Most people have heard of their gut microbiome. The microbes in our digestive system are important for our health from immune function to digestion (especially for dirt tasters). However, some microbes, such as the COVID-19 virus, can make us sick. Soil microbes in forests are not so different.

    Forests are dependent on microbes that cycle nutrients, decompose waster, and aid plants in nutrient uptake. Like humans and the common cold, some soil microbes hurt their associated plants. An example of this is kauri dieback disease, a disease spread by a spore in the soil that attacks tree roots and trunks. This disease hinders the tree’s ability to uptake and transport nutrients, essentially starving and killing the tree. Kauri dieback is incurable and fatal for kauri.

    Tāne Mahuta, the largest surviving kauri. Photo by Jodie Wiltse (Author)

    Kauri dieback is named after the tree it infects, New Zealand’s mighty kauri tree. The Department of Conservation explains that kauri can grow up to 16 m in circumference and live over 2000 years. The legendary status of kauri is clear in the language used to describe them. The largest surviving kauri is called Tāne Mahuta, which means ‘lord of the forest’. If you were to visit Tāne Mahuta today, you would find boot cleaning stations, warning signs, and only be able to view the great tree from a platform. Moreso, entire trails have been shutdown to stop people from spreading soil around kauri. Why?

    A soil microbe, Phytophthora agathidicida, travels under the name of kauri dieback. This microbe cannot be seen with the naked eye but has the power to kill tremendously large kauri trees. In humans, the heroic microbes of our immune system save us when nasty microbes make us sick. Are there unseen heroes hiding in the soil that can help kauri?

    During a PhD project at Lincoln University, Dr. Alexa Byers studied soil microbial communities under kauri to find out. The goal was to identify microbes that suppress kauri dieback and can aid in kauri conservation.

    The first step was to understand how microbial communities under kauri react to kauri dieback disease. Alexa infected kauri seedlings with kauri dieback and looked for changes in the soil microbial community. When humans are attacked by illness causing microbes, our immune system amps up to protect us. When soils were infected, Alexa found bacteria that were involved in disease suppression. This was a promising result suggesting that heroic soil microbes could build up their numbers to fight off kauri dieback.

    Kauri tree bleeding resin, a common symptom of kauri dieback disease. Photo by Onco p53 (CC BY-SA 4.0).

    Next, Alexa looked into how specific strains of bacteria from kauri soil impacted the development of kauri dieback. She identified Paraburkholderia and Penicillium microbes that inhibited the growth of kauri dieback in soils. Paraburkholderia are known to enhance plant growth and fix nitrogen. Penicillium are fungi that can kill or stop growth of other bacteria. We officially have some heroic contenders!

    The battles between heroic microbes and kauri dieback in the soil could determine the fate of the kauri above them. Hopefully, researchers can find a way to rig microbial battles in favour of these unseen heroes. More research is needed to determine their true potential, but these soil microbes could be called to action in the near future.

    The world under kauri is just one example of fascinating soil microbes. Soil microbes have been found to be key for carbon storage, impact the taste of tea, and reduce nitrogen runoff from agriculture, among many other amazing things. This is your reminder to appreciate the little things, even the things so little you cannot see them. Next time you play in a garden or walk through a forest, I hope you take a moment to think about all the tiny microbes working away in the soil to help (or hinder) plants and make the natural world work.

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

    Research Paper: Byers, A.K. (2021). The soil microbiota associated with New Zealand’s kauri (Agathis australis) forests under threat from dieback disease: A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University. Lincoln University. https://hdl.handle.net/10182/13887

  • Wilderness and the New Zealand mind

    “Wilderness was the basic ingredient of American culture. From the raw materials of the physical wilderness, Americans built a civilization. With the idea of wilderness they sought to give their civilization identity and meaning.” – Roderick Nash, Wilderness and the American Mind

    Since the advent of the wilderness preservation movement in nineteenth-century America, protecting wild places has meant more than simply protecting pristine ecosystems. Despite the priceless value our world’s rapidly diminishing untouched landscapes hold for biodiversity conservation, wilderness preservation has first and foremost been a cultural mission.

    Doubtful Sound, Fiordland National Park – Rod Waddington, licensed under CC BY-SA 2.0

    Roderick Nash described wilderness not as a type of ecosystem but as a “state of mind.” Investigating this mindset reveals much about our reasons for protecting nature and what nature means to our society. The people of New Zealand decided very early on that its natural landscapes were worth protecting, especially its most wild and remote places. Wilderness areas are now considered a “defining characteristic” of New Zealand, with many citizens feeling a sense of “pride” and “identity” with these wild areas.

    Wild nature, as opposed to pastoral or modified landscapes, provides many people a source of connection to the natural world that transcends typical nature amenity values. People who visit wilderness areas report experiences of the sublime, of incredible beauty, of solitude and personal growth, of the unrivalled rewards of physical challenge and overcoming risk, and of a connection with nature that is no less than spiritual. But while wild places are by definition areas with as little human modification as possible, their preservation and meaning in society are entirely human.

    University of Lincoln researcher Kerry Wray wrote their doctoral thesis on the meaning behind New Zealander’s relationship with wilderness. Kerry identified how differences in wilderness valuation say much about the country’s human-nature relationship and its internal conflicts. Wray’s thesis covers how reasons for conserving nature can come from our desire for a life of meaning and connection and how this desire can direct the course of an entire nation.

    Nations, as well as individuals, look to their landscapes for identity. Where we come from often says much about who we are. New Zealand became one of the first countries in the world to establish national parks, starting in 1892. The government enacted legislation that officially recognised national parks as “areas of New Zealand that contain scenery of such distinctive quality, ecological systems or natural features so beautiful, unique, or scientifically important that their preservation is in the national interest.” They saw them as so valuable and essential to the essence of the country’s identity that they should also be preserved in “perpetuity.”

    Statue of Sir Edmund Hillary in Mount Cook/Aoraki National Park – Geof Wilson, licensed under CC BY-NC-ND 2.0

    As the country set out to preserve its landscapes it did so in a way that reflected the collective personality of the nation’s citizens. The colonial inhabitants of this land saw themselves as pioneers and explorers. As the country transitioned from colony to statehood, it looked for ways to distinguish itself. It looked towards its unpeopled valleys, deep fjords, and soaring peaks.

    Vast swathes of wild New Zealand were and remain unlike any environment in Europe and the people that explored them saw themselves as likewise distinct. The country aimed to preserve areas for backcountry tramping and hunting, celebrating their cultural love of adventure, self-sufficiency, and exploration. And so, with a provision in the 1952 National Parks Act for remote places, the country became one of the earliest adopters of the wilderness preservation movement in the world, setting aside immense areas with policies more strict than any other country.

    There are now 6 designated wilderness areas in the country, with many more remote areas that are effectively managed as wilderness. Wilderness in New Zealand is now, mainly under the 1985 Wilderness Policy, legally considered a place undisturbed by humanity, free from infrastructure including the most basic of modifications, such as huts, bridges, signs, and even tracks.

    Wilderness preservation polices have now spread around the world, with leading international conservation organizations emphasising their immense ecological and cultural value, such as the European Commission’s issue of wilderness management guidelines, definitions, and calls for further preservation. The International Union for Conservation of Nature has created a global classification and management guidelines system for wilderness areas. There are also non-profits with storied conservation legacies, such as the Wild Foundation and Wilderness International. It was largely due to the inspired efforts of the Federated Mountain Clubs‘ love of remote back-country experiences that New Zealand wilderness now ranks among the most wild and protected in the world.

    The wilderness area of Fiordland National Park, now a World Heritage Area, is the largest and most representative of the country’s wild nature. It was here in 1773 that Captain Cook moored when plotting New Zealand on the world map. It was here in Fiordland that advancements in species conservation were made as early as the nineteenth century with the protection of entire off-shore islands and the conservation efforts of some of the world’s rarest birds, such as the kākāpō and takahē.

    In Fiordland, the ethos of wilderness preservation has led to the protection of the largest expanse of native forest in the country. For trampers, it is the most remote one can get on the mainland. However, it is also home to three of the nation’s Great Walks and a national park attracting nearly 1 million visitors a year.

    The Darran Mountains, Fiordland National Park – Dan Nelson, licensed under CC BY-NC-ND 2.0

    “Fiordland National Park represents a legacy of every New Zealander, for every park visitor; a cherished corner of the world where mountains and valleys compete with each other for room, where scale is almost beyond comprehension, rainfall is measured in metres, and scenery encompasses the broadest width of emotions. It is a place of solitude, of retreat, of quiet rejuvenation… Welcome to Fiordland, land of the last retreat” – Department of Lands & Survey 1986

    The increasing demand for access to wilderness areas and their peripheries is not only putting pressure on these fragile ecosystems but on users’ values as well. For one person, the Fiordland wilderness means the Milford Highway and they may bemoan the lack of tracks that enter into deeper sections of the park. While for others, wilderness is not reached until hiking several days away from the Park into untracked valleys and may picket propositions to improve trails and build huts. How the Crown decides to manage these conflicting user expectations can direct the course of nature conservation in New Zealand as a whole, a country with more ecotourists and backcountry users every year.

    Which values will be prioritised? What interpretation of wilderness will be used in future? And, is the idea of wilderness always appropriate? Can it be harmful?

    Sign in Kauri National Park – Eli Duke, licensed under CC BY-SA 2.0

    With over a third of the country set aside for conservation and with one of the most extensive and strictly defined wilderness preservation systems in the world, New Zealand is a model case study in the phenomenon of wilderness preservation. But it is a phenomenon that is only beginning to come to terms with its colonial heritage.

    That word, wilderness, as well as its connotation, do not translate well out its Germanic language roots. Many people and cultures around the world have differing conceptions and values of wild places. And the Europeans who pioneered the idea paid little attention to human-nature relationships already present in these allegedly pristine or “Edenic” places.

    Indigenous peoples were the first to suffer from modern conservation strategies. Not only were they displaced from their lands but their heritage and legacy were ignored or erased. For example, nearly all wilderness areas in the United States were inhabited by native peoples before being designated. The European-American cultural idea of civilization vs wild nature imposed itself atop hundreds of years of indigenous peoples’ heritage with these ‘wild’ places. Wilderness preservation has led to the degradation of global indigenous heritage and even overt oppression.

    Countries around the world are now reassessing their relationship with nature conservation, including New Zealand. The future of Fiordland National Park, with its 800-900 year history of Māori inhabitation, has complex and competing human-nature relationships to be considered. Certain conservation lands throughout the country are now being reclaimed by iwi. Concessions are being made to allow customary use of natural resources across Crown Land. Wilderness areas are now being criticised for concealing indigenous heritage and restricting rights.

    The wilderness landscape of New Zealand played a large role in the creation of a national identity and a conservation agenda post-independence. Now again the idea of wilderness will play a role in how the country decides to manage its conservation lands and for whom.

    Nature conservation in New Zealand means more than saving the endangered birds. It has to do with culture, the quest for identity and beauty, and now, also, justice. There are many definitions of wilderness but all of them speak of a place somehow both lacking in humanity and a place to be sought, a wasteland and a wellspring of emotion, somewhere unmarked by human hands yet telling of our passions.

    The road into Aoraki Mount Cook National Park – /\ltus, licensed under CC BY-NC-ND 2.0

    Kerry’s work is a landmark piece in the academic discussion of New Zealand wilderness management. The many intangible values of wilderness and its environmental justice issues make it a complex idea to study or even casually talk about. Yet, Kerry’s endeavor describes why wilderness values are so important and demonstrates that it is possible to study them and produce substantive ideas for addressing its many complex problems.

    William Cronon’s famous critique of wilderness preservation called wilderness a “monument to the nation’s past.” The mounting challenges to conservation lands press our eyes forward. How we decide to value our world’s diminishing wilderness speaks to how we will value nature all together and what the future landscape of this country will look like.

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

  • Repelling New Zealand’s deer: keeping the target on predators

    Imagine walking through the lush forests of New Zealand, where native birds sing and the ecosystem thrives. For many, the thrill of hunting deer adds to the adventure, as these animals are both prized game and an integral part of the environment. However, lurking within this paradise are predators, like possums and rats, which threaten the very fabric of this delicate ecosystem.

    To combat these problem predators, New Zealand has employed a controversial yet effective method: aerial 1080 poison drops. These toxins are effective against pests but can inadvertently harm other wildlife, including the beloved white-tailed deer (Odocoileus virginianus).

    White Tailed Buck.
    Brad Smith. July 3rd 2006

    White-tailed deer are not native to New Zealand; they were introduced for hunting in the early 20th century. Despite being an introduced species, they have established a stable population and have become an important part of New Zealand’s hunting culture, especially the population on Stewart Island. Protecting them is crucial not only for maintaining biodiversity but also for supporting the recreational and economic benefits associated with deer hunting.

    Recent studies have shed light on how we can minimise this collateral damage by using deer repellents. Let’s dive into the findings and their implications for both wildlife management and conservation.

    New Zealand’s unique biodiversity is under constant threat from invasive species. Possums, rats, and stoats prey on native birds, insects, and plants, disrupting natural ecosystems. To protect these vulnerable species, aerial drops of sodium fluoroacetate, commonly known as 1080, are used. This toxin is highly effective at reducing predator populations, but it’s not without its drawbacks. One significant concern is the unintended by-kill of non-target species, such as the white-tailed deer.

    Intensive ground-based searches for white-tailed deer carcasses were conducted in the Dart Valley/Routeburn catchments following the aerial application of 1080 cereal pellets as part of the ‘Battle for the Birds’/Tiakina Ngā Manu predator control program in August 2014. Lincoln University PhD student Kaylyn Pinney, with her supervisors James Ross and Adrian Paterson, organised this search. Four areas, each 100 hectares in size, were searched over four days. The results were published in NZ Journal of Zoology.

    To estimate the effectiveness of their search, simulated deer carcasses were used. The success rate for finding these simulated carcasses was 78%. All actual white-tailed deer carcasses found contained traces of 1080 in their muscle tissue (ranging from 0.41 to 1.06 mg/kg). Based on these findings, researchers estimated that approximately 3.85 deer per 400 hectares died from 1080 poisoning. This translates to a potential mortality of about 146 white-tailed deer across the entire 15,215-hectare predator control area. These results suggest that recurrent predator control operations could impact the sustainability of white-tailed deer hunting. (For more on this see ‘Is it fair, for orcs and deer?’)

    Repellents are substances designed to deter animals from consuming certain items without causing them harm. In the context of predator control, deer repellents can be coated on 1080 baits to reduce the likelihood of deer ingesting the poison.

    Kaylyn Pinney then tested a deer repellent-coated 1080 bait to see if it could reduce the mortality of white-tailed deer during predator control operations. She tested two types of repellents: Epro Deer Repellent (EDR) and Pestex-DR. The study was divided into two parts: trials in a captive herd on the West Coast and monitoring of wild deer fitted with GPS collars in the Dart/Routeburn Valley in Otago, New Zealand.

    Routeburn Valley.
    yiwenjiang26, Routeburn vally closer up. March 10 2007.

    In the captive trials, five deer were presented with three types of cereal baits: non-repellent (NR), EDR-coated, and Pestex-DR-coated. The baits were placed in a controlled environment where deer could freely choose among them. The results were promising. The deer showed a clear aversion to the repellent-coated baits, with significantly less consumption compared to the non-repellent baits. The repellents appeared to be effective, though not infallible. One older buck did consume a single EDR-coated bait initially but avoided it afterward.

    The second part of the study involved monitoring ten wild deer equipped with GPS collars during a 1080 drop. To fit the deer with GPS collars, Kaylyn and crew captured the animals by tranquilising them and then attached the devices. Kaylyn could now track their movements and monitor their survival. The results were mixed. One deer, the youngest in the study, died from 1080 poisoning, suggesting that body size may play a role in susceptibility to the poison. Importantly, the study confirmed, however, that using EDR significantly reduced deer mortality compared to previous operations without repellents.

    While the study shows that repellents can reduce by-kill, there are challenges. Ensuring that every bait is adequately coated with repellent is crucial. Additionally, different deer may react differently to repellents, as observed with the older buck in the captive trial. Kaylyn suggests that using a lower concentration of 1080, such as 0.08%, could further reduce deer mortality, especially for smaller deer.

    The study also highlights the importance of understanding deer habitat use. The GPS collars allowed researchers to identify how much time the deer spent in different types of habitats. The varied exposure of the collared deer to the 1080 baits was influenced by their movement patterns and habitat preferences. Future studies should consider these factors to optimise bait distribution and minimize non-target impacts.

    1080 Warning Sign.
    Shaddon Waldie, 1080. July 30th 2009.

    These findings have significant implications for wildlife management and conservation in New Zealand. By using deer repellents like EDR and Pestex-DR, we can make predator control operations more targeted and reduce the unintended consequences for non-target species. This approach not only helps protect the native ecosystem but also addresses public concerns about the humane treatment of wildlife.

    The study underscores the need for continuous innovation and adaptation in conservation strategies. As we gain more insights into the behaviour and ecology of both target and non-target species, we can develop more effective and sustainable methods to preserve New Zealand’s unique biodiversity.

    The journey to protect New Zealand’s native species is complex and challenging. This study offers a glimmer of hope by demonstrating that deer repellents can significantly reduce the by-kill of white-tailed deer during aerial 1080 operations. While not perfect, these findings pave the way for more refined and humane conservation practices. As we continue to balance the needs of predator control with the protection of non-target wildlife, studies like this guide us toward a more sustainable and harmonious coexistence with nature.

    Imagine once again walking through those lush forests, now knowing that both the native birds and the majestic deer can thrive in a balanced ecosystem.

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

    Link to the main article

    Pinney, K. A., Ross, J. G., & Paterson, A. M. (2022). Assessing EDR and a novel deer repellent for reducing by-kill of white-tailed deer (Odocoileus virginianus), during aerial 1080 operations. New Zealand Journal of Zoology, 49(3), 199–214. https://doi.org/10.1080/03014223.2021.1978510

    Additional Links and Further Reading

    New Zealand Department of Conservation

    The New Zealand Department of Conservation (DOC) website provides comprehensive information about New Zealand’s natural heritage, conservation efforts, and recreational opportunities. Key sections include:

    Parks & Recreation: Information on places to visit, activities, camping, and hiking.
    Nature: Details on native plants and animals, pest management, and habitats.
    Get Involved: Volunteering, funding opportunities, and educational resources.
    Our Work: Conservation projects, research, and monitoring programs.

    Manaaki Whenua – Landcare Research

    The Manaaki Whenua – Landcare Research website provides a wide range of information on New Zealand’s land environment and biodiversity. It covers research areas such as soil health, water management, biodiversity conservation, and climate change. Additionally, it offers resources for educators, data and mapping tools, and information on various conservation projects. The site also features sections for news, events, and opportunities for public involvement in environmental efforts.

    1080: An Overview

    The “1080: An Overview” page on the Predator Free NZ Trust website provides comprehensive information about the use of 1080 (sodium fluoroacetate) in New Zealand for predator control. It details what 1080 is, why it is used, its application methods, and its effectiveness. The page also covers the benefits and risks associated with 1080, including its impact on native species, non-target species, and the environment. Additionally, it includes examples of successful 1080 applications and addresses common concerns such as its impact on drinking water.

    Nugent, G., & Yockney, I. (2004). “Feral deer in New Zealand: current status and potential management.” New Zealand Journal of Zoology.
    This article discusses the status and management of feral deer populations in New Zealand.

    Morriss, G. (2007). “Epro Deer Repellent reduces by-kill of deer during aerial 1080 operations.” Landcare Research Report.
    This report provides detailed findings on the effectiveness of EDR in reducing non-target by-kill.

    Frampton, C. M., et al. (1999). “Efficacy of 1080 carrot baits in controlling possums.” New Zealand Journal of Ecology.
    This study examines the effectiveness of 1080 in controlling possum populations.

    Spalinger, D. E., et al. (1997). “Influence of learning and experience on foraging behavior of white-tailed deer.” Journal of Wildlife Management.
    This research explores how learning and experience affect deer foraging behavior.

    Bowen, L. H., et al. (1995). “Leaching rates of 1080 from RS5 cereal baits under simulated rainfall.” New Zealand Journal of Ecology.
    This paper discusses how environmental conditions affect the concentration of 1080 in baits.

    Pinney, M., et al. (2020). “Effectiveness of deer repellents in reducing non-target by-kill during predator control operations.” Journal of Wildlife Management.
    This study delves into the specific effects of deer repellents on non-target species during 1080 operations.

  • Lonely nature: the fear of suburbia

    Blandly pleasant houses flank wide roads. Inoffensive strip gardens line dull driveways and plain, wooden slat fences. Every street is perfectly plain and welcoming. The normal neighbourhood stretches on, unchanging for blocks.

    If you have looked for a house, flat, or rental in the past fifteen years, you have visited this suburb. Welcome home.

    Does anyone else listen to the Magnus Archives? It’s a fictional horror podcast where an archivist records first hand accounts of people pursued by manifestations of their own fear, including the fear of always being watched, hunted by dark beasts, or being horribly, completely alone. The endless suburbia described above is from one of these accounts: an episode named Cul-de-sac.

    Horror employs the unknown, unnatural, and surreal to frighten its audience. I find it disconcerting that modern suburbia is considered uncomfortable enough to feature. Scarily, it works. In this particular account, the writer finds themselves alone in a desolate suburban neighbourhood, absent of life and vigour. Nothing defines one home from the next. Gardens are non-existent, and no other living thing is present. Why is this dull repetitiveness so horrifying?

    Our homes define us as much as we define them. When an area is so lacking in character, in life, it ceases to be a place at all. Global trends of urban design (especially in western countries) have spent decades prioritising vehicles over personal well-being, land-use diversity, and ecosystem health. Poor planning has resulted in biologically desolate, emotionally draining landscapes that we spend our entire lives in. Some land uses, such as industrial, are considered incompatible with nature. As a result, suburban design has an imperative theatre to reintroduce biodiversity into our every-day lives.

    “The normal just seemed to go on forever.” The Archivist, The Magnus Archives. Episode 150 “Cul-de-sac”.
    Image: Author. All rights reserved.

    In 2008, Maria Ignatieva, Glenn Stewart, and Colin Meurk published an article in the New Zealand Landscape Review titled: “Low Impact Urban Design and Development (LIUDD): Matching Urban Design and Urban Ecology.” They recognised New Zealand’s poor history in applying ecological principles to landscape design, which has led to the depreciation of native biodiversity, landscape legibility, and the tidal wave of invasive exotic organisms. Global trends, such as rewilding in the UK, nurture communities that respect, conserve, and enhance natural processes. This is not easy, as ingrained cultural perceptions of our relationship with ecology are complex. As put by Joan Nassauer in her article Messy Ecosystems, Tidy Frames:

    “People may care about improving ecological quality, but not at the expense of the proper perception of their own landscape”

    Socio-cultural norms borne from the picturesque design movement still drive perceptions of how landscapes should appear, more than 200 years after they were conceived. To see an iconic picturesque landscape, take a glance at this article on Stourhead Gardens in England. These preconceived values, lack of diversity, and cost-driven urban development result in homogenised, unlively neighbourhoods; perfect habitats for Cthulhu-esque, eldritch beings to consume lonely creatures’ fears in, but less perfect for our native flora and fauna.

    Two key methods of Low Impact Urban Design and Development were identified to address these issues: designing for sense of place (to improve public perceptions), and for native biodiversity. As an example, Ignatieva and colleagues suggest the use of ‘plant signatures’ in suburban design. These signatures are assortments of plants that provide context clues of the landscape; species are chosen deliberately to represent the ecological needs and habitat functions of that environment. This contrasts with most plant selections which are often driven by cost, function, or amenity driven calculations. Character and identity are inherent in an ecologically aware plant palette, and designers worth their salt should demonstrate this in thoughtful design choices.

    A stormwater system in Te Whāriki subdivision, Lincoln. Image: Author. All rights reserved.

    These ideas have been present for decades: plant signatures were coined by Nick Robinson in 1993, and Ignatieva and colleagues’ article was published 16 years ago. So, what effect have Low Impact Urban Design and Development and plant signatures had on increasing urban biodiversity? I met with Colin Meurk, one of the authors, to hear his thoughts. “Low Impact Urban Design and Development is pretty much history, apart from the legacy effect,” he said. “We use different jargon now.” Oh. Right.

    The thing is, just because ideas are innovative does not mean they are embraced and applied. In places, Low Impact Urban Design and Development has successfully evolved– Meurk points to stormwater design and ‘sponge cities’ as evidence that ecological concepts can assimilate successfully into current landscape practice.

    Te Whāriki in Lincoln is a great example of this: as a result of high clay soil and ground-fed springs, this subdivision needs to detain high levels of stormwater. The standard method to do so is with large grass-mown basins, such as those seen down the road in Wigram. Instead, Te Whāriki is designed with extensive wetland systems that support a wide range of native plants, bird species, and invertebrates. The wetlands also provide excellent public spaces, with walking tracks, seating, and street-inter-connectivity. My own parents chose Te Whāriki as their new home in 2022 specifically for the wetlands!

    A path through a stormwater system in Te Whāriki subdivision, Lincoln. Image: Adrian Paterson.

    Yet, ecological principles within suburban design are the exception rather than the rule. Is this because ecological action is still viewed in opposition of cultural values, as Nassauer would suggest? Is it that policy makers do not sufficiently emphasise ecological principles, or because developers dislike the financial ‘deadweight’ of ecological oriented design?

    I would suggest all three, although there is greater nuance and complexity than I have room to explore here. Notably, Te Whāriki was developed by Ngāi Tahu in conjunction with Lincoln University, both parties whom have a vested interest in increasing biodiversity in the region.

    It is disquieting that a common expression of modern living is easily utilised as a metaphor for horror and loneliness. What does it say about modern design that it can easily parallel horror and fear? When we met, Colin Meurk labelled modern subdivisions as an ‘extinction of experience’.

    Younger generations are often criticised for spending too much time on technology, but when they live in lonely neighbourhoods, can we blame them? In failing to design for biodiversity, we rob ourselves of opportunities to experience the natural world. Low Impact Urban Design and Development may have been subsumed into other concepts, but designing in a manner conducive to the natural world and people is more relevant than ever. Plant signatures are an excellent method to incorporate biodiversity and character in our suburbs. Birds, invertebrates, reptiles – they would love to take part in our neighbourhoods, and I, for one, would prefer a lively neighbourhood over a horrifying, lonely suburbia.

    Life provides. Image: Author. All rights reserved.

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

    Reference Article: Ignatieva, M., Meurk, C. D., & Stewart, G. H. (2008). Low impact urban design and development (LIUDD) : matching urban design and urban ecology. Landscape Review 12(2):61-73.

  • Induced resistance, Sting, and the blades of Westernesse

    It’s a big, bad world out there and it is nice to find something that adds to our protection.This can range from vaccines against viruses, to seatbelts in cars, to laws against causing physical harm. As a naked ape we are not especially intimidating on our own and we often seek out tools to make us safer.

    “With both hands he held the elven-blade point upwards …; and so Shelob, with the driving force of her own cruel will, with strength greater than any warrior’s hand, thrust herself upon a bitter spike. Deep, deep it pricked, as Sam was crushed slowly to the ground.
    No such anguish had Shelob ever known, or dreamed of knowing, in all her long world of wickedness. Not the doughtiest soldier of old Gondor, nor the most savage Orc entrapped, had ever thus endured her, or set blade to her beloved flesh.” Lord of the Rings, JRR Tolkien (Image by Tony Galuidi; main image by Alan Lee)

    One of the key points of “The Lord of the Rings” (and all of Tolkien’s writing) is that small, seemingly ineffectual, individuals can make a real difference in the world. It’s not by chance that hobbits are smaller than humans, weaker than dwarves, less knowledgeable than elves. Tolkien emphasised their ‘normality’.

    Hobbits do have their strengths though, especially in resilience. They are able to withstand the corruption of the ring far longer than other races. Boromir, a doughty man, only has to see the ring once before plotting to ‘borrow it’ for helping with his people. Both Bilbo and Sam, ordinary hobbits, are both able to wear the ring and give it up freely, which no others have done.

    Still, even Tolkien realised that the hobbits needed a little bit of an assist, something that would help to bring out their resilient traits. Tolkien chose to give each hobbit a long dagger with an ancient pedigree. Sting was found by Bilbo. It was a blade that shone with a faint light when evil was near. Sting was made long ago in the first age by elves of Gondolin. Tom Bombadil rescues the hobbits from a barrow wight and gives them each a dagger of Westernesse. These were made a couple of thousand years before in the early Third Age by men of the Dunedain Northern kingdom.

    Each of these blades become crucial to the hobbits achieving beyond their expectations. Pippin stabs a troll chief, who are largely immune to most weapons, and makes a difference at the Battle of the Moranon. Merry cuts the Witch King’s sinews allowing Eowyn to destroy the head Nazgûl in the Battle of the Pelennor Fields, when no one else can touch him. Sam uses Sting to wound Shelob and scare her off, when nothing else would work.

    Importantly, the blades were built with different foes in mind. The blades of Westernesse were built to fight the Witch King and his minions but are useless against giant spiders. Sting was built at a time when Ungoliant’s spider brood were numerous and roaming the world, and so it is effective against Shelob and her webs.

    Merry stabs the Witch King and breaks the spell allowing Eowyn to destroy him.
    “No other blade, not though mightier hands had wielded it, would have dealt that foe a wound so bitter, cleaving the undead flesh, breaking the spell that knit his unseen sinews to his will.” – Lord of the Rings, JRR Tolkien

    So, the hobbits left the Shire with their natural hardiness and common sense, but were primed with blades to make themselves more resilient to the difficult situations that they were to face.

    There is a similar concept when it comes to immune systems. Most plants and animals have evolved sophisticated immune systems that respond to pathogens in the surrounding environment. Having a complex immune response is especially important in dense populations where disease and parasites can quickly spread. One such situation is with crop species.

    Crops, where individuals from one species are packed tightly together, are targets for various pest species that can infect an individual and easily move to the next. For the last 100 years or so we have had the luxury of applying chemicals to help keep the plants healthy by reducing pathogens. This is no longer an an attractive option as it once was as pathogens have become resistant and people have become less tolerant of nasty chemicals in their landscapes and food sources.

    One solution is to create induced resistance through biological and chemical inducers. These inducers can artificially trigger immune defences and enhance their responses. For example, grape crops can suffer from downy mildew. Chitosan, a sugar obtained from the shell of crabs, can be sprayed on vines, triggering immune responses that can reduce downy mildew by 90%, compared to what would happen if grapes responded ‘normally’!

    “His little sword was something new in the way of stings for them. How it darted to and fro! It shone with delight as he stabbed at them.” The Hobbit, JRR Tolkien (Image by J. Catlin)

    Just like the blades of Westernesse helped the hobbits, these inducers allow the individuals to respond faster, more intensely, and achieve more than they would otherwise be able to do. Some inducers are useful for a variety of pathogens in many crops, such as Acibenzolar-S-methyl (ASM), and some are very specific, such as Saccharomyces yeast extract.

    Helen Rees, Lincoln University, and colleagues from Plant and Food, University of Auckland, and Scotland’s Rural College have put together a review in the journal Phytopathology about where the field of induced resistance in crop species stands. They look at what has worked on particular crops and the future roles and opportunities for inducers. They conclude that it is an exciting time for this field and that future crop protection may revolve around the next generation of inducers, playing a pivotal role in moving to a reduced pesticide future.

    While inducers may not have the glamour of a Bilbo using Sting to free dwarves from giant spider webs in Mirkwood, they have world-wide contributions to make to feeding a hungry planet by countering the ravening hordes of crop pathogens. Cutting edge indeed!

    Adrian Paterson is a lecturer in Pest-Management and Conservation at Lincoln University. He likes Sting (both in the Lord of the Rings and in The Police).

  • Under the southern moss

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

    A lost world?

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

    How accurate is this?

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

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

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

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

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

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

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

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

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

  • Darwin and the Sandwalk: bike

    Darwin took the best part of 20 years to publish his ideas on natural selection. There has been a lot of speculation as to why he took so long. We here at the Sandwalk have some ideas….

    Although bicycles, as we know them, were still a decade or two off, in the early 1850s there were various forms of velocipedes with experimental modes for generating movement. Darwin may have come across some. Presumably, if bikes had been around at this time he would have been a mountain-biker, going off the beaten tracks to investigate bits of natural history. The Sandwalk, where Darwin liked to amble and ponder over his ideas, would have made for a nice place to warm up. Add in some jumps and stream crossings and it would be ideal.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

    Further reading

    Practical guide for landowner and farmers for landcare

    Improving biodiversity – Beef + lamb

  • Remove one NZ invasive mammal predator and another steps into its place

    Invasive species are a major concern for ecosystems worldwide, causing significant disruptions to native flora and fauna. Some mammals can have particularly devastating effects on local ecosystems due to their predatory nature. In the Hawke’s Bay, New Zealand, a recent study titled “Niche Partitioning in a Guild of Invasive Mammalian Predators” sheds light on the dynamics of invasive mammalian predators and their impact on the region’s native biodiversity.

    I’ll walk you through the key discoveries and explain why they hold immense importance in our understanding of niche partitioning and its implications for ecosystem management.

    Niche partitioning refers to the process by which species with similar ecological requirements coexist within an ecosystem by utilizing different resources or occupying different ecological niches. Niche partitioning reduces direct competition, promoting the coexistence of species that would otherwise struggle to survive in the same habitat.

    In Hawke’s Bay, a guild of invasive mammalian predators has established, comprising three key species: stoats(Mustela erminea), ferrets (Mustela furo), and feral cats (Felis catus). 

    These predators were introduced to New Zealand and have since wreaked havoc on many native bird populations. Recent studies have revealed an intriguing pattern of niche partitioning among these invaders, suggesting a potential balance within the guild.

    Camera traps were deployed in three seasons. Credit by Albert Salemgareyev/ACBK

    Researchers have observed distinct differences in the dietary preferences and hunting strategies among these invasive predators in Hawke’s Bay. These variations have allowed the species to exploit food, reducing direct competition and encouraging the peaceful coexistence of individuals.

    Stoats, being the smallest and most agile of the three predators, specialize in hunting rats, mice, and birds. Their slender bodies and keen sense of hearing enable them to pursue their prey with stealth and precision. Ferrets, on the other hand, are larger and more versatile, adapting to different types of prey or using various hunting techniques. Ferrets tend to target larger prey, such as rabbits and small hares, which they capture using their strength and speed. Feral cats, similar to stoats and ferrets, are solitary hunters, exhibiting a broader dietary range, preying on both small and medium-sized mammals, birds, and reptiles.

    While the predators may occasionally target overlapping prey species, they generally exhibit distinct foraging preferences and occupy different microhabitats. Stoats predominantly inhabit forested areas, where their excellent climbing abilities give them an advantage in pursuing prey in trees.  Ferrets, with their larger size and ground-based hunting strategies, are often found in open grasslands and shrublands. Feral cats, being highly adaptable, can exploit a range of habitats, from dense forests to human settlements.

    The phenomenon of niche partitioning among invasive predators in Hawke’s Bay has important implications for native species conservation. By occupying different ecological niches, these predators help reduce the burden on specific native animals in an indirect manner, allowing them to persist despite the presence of invaders.

    Bird species, in particular, have been heavily impacted by the invasion of mammalian predators. Native birds, such as kiwi, weka, and tui, have experienced population declines due to predation. However, the niche partitioning observed among invasive predators offers a glimmer of hope for the survival of some native bird species. For example, stoats target ground-dwelling birds, while ferrets focus on larger prey, like rabbits. This division of labour reduces the overall predation pressure on specific bird species and allows them to maintain a foothold in their respective habitats.

    Stoats are tricky to study. They are hard to find in the field and difficult to keep in captivity. Image from Adrian Paterson.

    Understanding the dynamics of niche partitioning among invasive mammalian predators can inform targeted conservation strategies. By recognizing the specific resources and habitats favored by each predator species, conservationists can create plans for managing natural areas that utilize the division of habitats to safeguard endangered native animals.
    Implementing effective trapping and removal programs, focused on the specific predators posing the greatest threat to certain bird species, can help alleviate their population declines.

    Habitat restoration initiatives aimed at enhancing native bird habitats, while creating barriers for invasive predators, can further support the survival and recovery of endangered species. For instance, Wellington, Zealandia is a 225-hectare fenced sanctuary dedicated to protecting and restoring native wildlife. The sanctuary is predator-free and provides a safe haven for endangered bird species like the tīeke (saddleback), kākā, and hihi (stitchbird). Zealandia also conducts active predator control outside the sanctuary to create a buffer zone for native birds.

    The study on niche partitioning among invasive mammalian predators in Hawke’s Bay offers valuable insights into the complex interactions within ecosystems and the potential consequences of invasive species on native biodiversity. These findings provide a foundation for conservation efforts and ecosystem management strategies aimed at mitigating the negative impacts of invasive predators on native flora and fauna. By understanding the dynamics of invasive species, we can work towards restoring and preserving the delicate balance of ecosystems, ultimately fostering a more sustainable future for our planet.

    Removing cats and ferrets from an ecosystem often has unforeseen consequences, as evidenced by the subsequent increase in site use by stoats. Stoats, cunning predators known for their ability to adapt to changing circumstances, have exploited the absence of cats and ferrets to their advantage. In the absence of these competitors, stoats have become more active during the day, closely following diurnal bird activity. This behavioral shift has raised concerns among conservationists, as it highlights the need for predator control measures to account for the specific hunting patterns and preferences of different predators.

    Failing to address this issue adequately could lead to a worse outcome for daylight birds, whose vulnerability to stoat predation may increase if their activities are not considered in predator control strategies. Therefore, it is crucial for ongoing conservation efforts to not only focus on removing invasive predators but also to consider the complex interactions among species and the potential cascading effects that may arise.

    This article was prepared by Master of International Nature Conservation student Albert Salemgareyev as part of the ECOL608 Research Methods in Ecology course. Albert won a prestigious Whitley Award for Conservation in 2023.

    Garvey, Patrick M., Alistair S. Glen, Mick N. Clout, Margaret Nichols, and Roger P. Pech. 2022. “Niche Partitioning in a Guild of Invasive Mammalian Predators.” Ecological Applications 32(4): e2566. https://doi.org/10.1002/eap.2566