EcoLincNZ

Category: Uncategorized

  • 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 

  • Tricks of the underground trade: networking below the vines

    Life in the soil can be a tricky business for plants and microbes. Nutrients are a limited commodity for some, and competitors may swindle and cheat to gain the upper hand. Strategic partnerships are highly sought after enabling exchange of one commodity for another within elaborate networks.

    In a tough economy, well-connected networks promote resilience, sharing of ideas and opportunity to those participating in mutual exchange. However, an efficient network should be an intentional one. Making simple connections is one thing, but choosing the right friends and trade partners is another.

    Although it may not appear that obvious on the surface, most land plants are proficient networkers. Below ground, plants form selective partnerships with microorganisms in the soil to access nutrients, water, and protection from pathogens. Those with strong networks are favoured in times of scarcity and change.

    Fungal mycelium consisting of thread-like hyphae. Photo by Lex vB at Dutch Wikipedia, (CC0 1.0)

    Within soil communities, fungi known as mycorrhizae play a major role in the growth and survival of plants. It is estimated that more than 80% of vascular plants form partnerships with mycorrhizae, an ancient evolutionary network approximately 450 million years old.

    Mycorrhizae are of particular importance in the viticultural industry as grapevines are highly reliant on these partnerships for growth and nutrient uptake influencing grape composition, vine health and occurrence of disease. In fact, grapevines form associations with entire communities of mycorrhizae known as arbuscular mycorrhizal fungi (AMF).

    AMF form close associations within the root tissue of plant hosts through specialized tree-like structures called arbuscules. These allow exchange of mineral nutrients from the soil for carbon fixed by the plant host which is transferred through the extensive hyphal network in the soil. These hyphae form interconnected “superhighways” within the soil, linking neighbouring vines and nearby crops transferring nutrients, such as nitrogen, from one host to another.

    Arbuscule of Rhizophagus irregularis colonising a plant root. Photo by Hector Montero, Flickr (CC BY-SA 2.0)

    AMF are highly diverse and have different effects on nutrient uptake and growth on grapevines. Depending on the situation, AMF can have positive, neutral, or negative effects on plant growth and stress resistance. However, under field conditions, plants are selective in the networks they build. These communities perform a diverse range of functions which collectively contribute to plant health and characteristics. Therefore, investing in the right trade partners is crucial.

    Until recently, the effects of whole AMF communities on grapevines had been largely unexplored. A research project at Lincoln University lead by Dr. Romy Moukarzel sought to understand how AMF different communities influence nutrient uptake and growth of different grapevine rootstocks. 

    In other words, who are the trade partners behind the vines and what is the return from these communities?

    To answer these questions, AMF communities were recovered from the roots of three different grapevine rootstocks across three different vineyards. Each rootstock was inoculated with its own (“home”) community or communities from other rootstocks (“away”) within three different vineyards. Vine growth, nutrient uptake, and chlorophyll levels were measured to find out if different communities had positive or negative effects on the different rootstocks.

    Consistent with previous work, different vineyards and rootstocks had their own unique communities. Growth and nutrient uptake differed depending on the composition of the community and rootstocks responded differently to the same communities. While some species in these communities improved nutrient uptake, others improved growth. In particular, a diverse community with a large representation of AMF of the Glomeraceae family resulted in the greatest increase in grapevine growth.

    In one vineyard, home advantage was also evident with “home” communities having greater increase in vine growth compared to “away” communities. Interestingly, when the amount of each AMF inoculum was equalised, home advantage was no longer observed.

    By changing the community composition, the positive effects on plant growth were reduced.

    New Zealand vineyard. Photo by Jorge Royan (CC BY-SA 3.0)

    Moukarzel and colleagues suggested that altering the composition may have resulted in competition between AMF leading to reduced positive effects on the host. AMF are known to compete for host resources, soil nutrients and colonisation sites. As a result, cooperation, and rivalry between AMF within different communities may have major implications for vine productivity.

    So, what can grapevines teach us about networking?

    Basically, choose your trade partners wisely. Identify friends and adversaries within the network and invest in those relationships with the greatest return.

    As proposed by marketing expert, Porter Gale: the so-called ‘new model’ of networking should focus less on ‘handing out as many business cards as possible’ and more on making connections based on how you want to grow. In other words, efficient networking should focus on investing in specific needs and interests. A well connected network with diverse partners offers wide opportunity and stability if components are co-operative.

    Overall, the findings generated from the study will be an invaluable insight towards leveraging AMF communities to target specific growth and nutrient requirements of grapevines. This is of particular importance to the viticultural industry as the composition of these communities play an important role in determining vine health, yield, nutrition, grape composition, and wine characteristics.

    Featured image: vineyard inter-row by rawpixel.com (CC0 1.0)

    While this study has provided a step towards understanding the communities below the vines, soil is a complex system with a wide range of players and there is much to learn about the orchestration of these networks. There are likely many more tricks of the underground trade to uncover.

    Moukarzel, R., Ridgway, H. J., Waller, L., Guerin-Laguette, A., Cripps-Guazzone, N., & Jones, E. E. (2022). Soil Arbuscular Mycorrhizal Fungal Communities Differentially Affect Growth and Nutrient Uptake by Grapevine Rootstocks. Microbial Ecology. https://doi.org/10.1007/s00248-022-02160-z

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

  • Buried treasure: the hidden gems of alpine peatland

    Growing up, I had a fascination with pirates.

    I’m not sure if it was the fact that they stole buried treasure, sailed the seven seas, and broke all the rules or if I liked that they used the term “swashbuckling” to describe themselves. All I know is that I wanted to be exactly like Captain Jack Sparrow. Granted, Johnny Depp does quite well at making Jack Sparrow seem like the best and worst pirate at the same time, which definitely influences the likeability and comedy factor of the character.

    Peat Area in Perigi village, Pangkalan Lampam District, Ogan Komering Ilir Regency.
    Photo by Rifky/CIFOR cifor.org, CC BY-NC-ND 2.0 (Flickr)

    For the majority of the first Pirates of the Caribbean: The Curse of the Black Pearl, Sparrow, with the help of his slightly awkward, bumbling, and unlikely traveling companion, Will Turner (played by Orlando Bloom), attempts to chase down his precious pirate ship and crew of the Black Pearl.

    To steal back his ship and find treasure along the way, Sparrow and Turner must make their way through various tunnels and streams until they finally reach the be-all-and-end-all of all treasure rooms, full of the loot that the pirates have collected over the years.

    Oftentimes, to get to these places of “great treasure”, the pirates would use maps to find the hidden jewels they so desired, and if they were underground, well, they would dig for them!

    But what if hidden gems are not always jewels?

    Even Sparrow, the death-defying pirate who escapes prison, steals ships, drinks copious amounts of rum and loves treasure, says:

    “Not all treasure is silver and gold, mate.”

    Treasure is “wealth stored up or hoarded, something of great worth or value” and “a collection of precious things,” according to Merriam-Webster Dictionary. In terms of natural resources, water is a treasure.

    Water is crucial for humans. Water is also a critical worldwide currency and supports life as we know it. Beyond using water for cooking, cleaning, or washing, water is critical for supporting agricultural crops, farms and, therefore, our food sources. In many communities, water also has a spiritual value, more than a monetary or physical value. In New Zealand, the Whanganui River even has personhood status, highlighting just how important water is.

    Considered a natural treasure, water is extremely precious in dry, arid regions with little rainfall or annual precipitation, meaning plants and animals must adapt to limited water sources. The same applies to agriculture; farmers must adapt in dry regions, using water sparingly and wisely. In these regions, it is essential to understand where water comes from and goes to and how it is potentially stored underground upstream from agricultural land.

    Buried treasure, some might say.

    In the arid Chilean Andes, this treasure is buried in mountain peatland.

    Peatlands are wetlands with layers of compact and partially decomposed plants and organic material (i.e., dead and decaying plants) in water-logged soil. If you’ve heard of the “Tollund Man” (a well-preserved body from the Iron Age), then you’ve heard of peatland. Peatland may have standing water or vast swaths of very soggy ground, as pictured below. This makes it difficult to immediately understand their capacities to hold water.

    Great Kemeri Bog, Latvia. Photo by: Runa S. Lindebjerg, CC BY 2.0 (Flickr)

    Shelly MacDonell (Lincoln University) and a team led by Remi Valois and Nicole Schaffer investigated the ability of Chilean peatland in the Elqui Valley to store water and estimated its role in delivering water to agricultural areas via streams.

    The researchers chose a peatland (bofedal) in Spanish, called “Piuquenes” for their study because of its central location compared to surrounding peatlands and its elevation (approximately 3000 meters above sea level), making it a great representation of other Chilean alpine peatlands. This peatland was also chosen based on a proposal to place a dam at the edge of Piuquenes for agricultural water control downstream.

    To study the inner workings of Piuquenes, the researchers had to look below the surface. Picture someone on the beach using a metal detector to find potentially valuable items under the surface (like a modern-day pirate), and that is a very simplified view of the tools used to visualize the geology and structure of the peatland below the surface. However, using Ground Penetrating Radar (GPR) and Electrical Resistivity Tomography (ERT), the researchers were able to create a 3D image of what might be under the surface. Through this 3D image, they could calculate the potential storage capacity (volume) of the studied peatland and estimate the role of high-alpine peatland in the area’s water cycle.

    According to estimates by researchers, the peatland itself could hold between 164,000 and 243,000m3 of water. That’s between 66 and 97 Olympic-sized swimming pools worth of water!

    The study found that the Piuquenes peatland can actually contribute water to lower agricultural regions downstream. However, the peatland is also vulnerable to water loss through evapotranspiration, which is a fancy word for water that evaporates and is lost from the vegetation and soil.

    Despite this water loss, researchers determined that Piuquenes was still important for supporting the surrounding ecosystems and could still act as a significant reservoir (i.e., source of water) for downstream agriculture and livestock grazing. They also discovered that the peatland could shield the area from drought impacts because of its water capacity. This means Piuquenes peatland could deliver water to grazing and low land agricultural areas via streams and limit the most severe effects of drought even in low-rain seasons.

    In addition to storing water, the Piuquenes peatland can also help produce soil from the slow build-up of decaying plants, store carbon, help plants grow and provide watered grazing areas for livestock.

    Understanding the inner workings of Piuquenes advances our knowledge of high-alpine peatland and its natural benefits to lowland agriculture. This study also adds valuable information to the discussion of if and how a dam should be built at the edge of this high-alpine peatland.

    Piuquenes, although located in the Chilean Andes, is an excellent example of how critical preserving and conserving peatlands worldwide.

    Studies have further investigated the secrets and treasures of peatlands, such as the carbon storage capacity, internal chemistry and nutrient cycling effects on methane emissions, proving that peatland continues to be a valuable ecosystem and that there is indeed treasure hidden beneath the surface.

    Peatland in Torronsuo National Park, Tammela, Finland. Photo by: Tero Laakso, CC BY 2.0 (Flickr)

    Current efforts have also focused on how to conserve these valuable landscapes and how local management initiatives could be applied worldwide. For example, Global Peatlands Initiative is a group dedicated to informing people about the importance of peatlands and keeping you updated on peatlands around the world.

    I’m pretty sure Jack Sparrow wasn’t referring to peatland as the treasure in his quote about silver and gold, but he was on the right track. If only he had known about the inconspicuous treasure hidden in the high reaches of the Andes!

    So, next time you’re on a swashbuckling adventure, keep your eyes open for what might be lurking under the surface and could be even more precious than silver or gold.

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

    P.S. Here is a really cool (and short) video about Peatland Protection from the UN!

  • Small animals show us the value of old natural forests

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

    Link to the research article:

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

    Read more:

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

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