EcoLincNZ

Category: ecosystem services

  • Sounds idyllic

    As a kid I explored the waters of the Marlborough Sounds. I caught my first fish there at seven years old and, one New Year’s day, my biggest snapper weighing about 25 pounds. I have been awed by watching fish and bird feeding frenzies- the food chain in practice. I learnt to dive off boats in emerald waters and spent many evenings watching the sunset and roasting s’mores at an isolated and tranquil DOC campsite. A place we call our “bach”.

    But I have never seen a Southern Right Whale, nor an Elephant Seal, or a Waitaha Penguin, in the Marlborough Sounds. Prior to my childhood it was a different Marlborough Sounds. Stephen Urlich and Sean Handley delve into the historical changes of this beautiful location, exploring how food webs have been disrupted since human settlement. The aim of the study was to address knowledge gaps by taking an integrated approach to examining how land use has impacted on coastal ecosystems.

    Stephen and Sean focused on keystone species. They traced the history of whaling in Port Underwood, within the Sounds. When John Guard’s first whaling ship entered the harbour in 1828, whales were abundant. Sadly, by 1836, there were 18 vessels sending out 70 whaling boats to chase these majestic creatures. Whaling led to a significant transformation of the Sounds’ ecosystem.

    Image by Author- Out in the Sounds

    Keystone species, like the Southern Right Whale, play a crucial role in transferring energy within the coastal food web. Their role as ecosystem engineers, essential for habitat formation, was lost by human greed. Sadly, as the authors remind us, the Southern Right Whale was not the first animal hunted by humans in the Sounds. During Maori colonisation, the Elephant Seal, New Zealand Fur Seal, New Zealand Sea Lion, and Waitaha Penguin were all harvested. Hunting led to the decline of the Fur Seal population and the local extinction of the Sea Lion, Elephant Seal, and the Waitaha Penguin.

    What is happening to our waterways? Who is responsible for the ongoing transformation of precious natural environments? Us. Once the habitats of the Marlborough Sounds flourished. The study highlights that in the past, there were various subtidal habitats formed by species such as giant kelp forests, as well as communities of hydroids and sponges. As early as 1863 there was dredging for oysters in the Tory Channel and trawling began in 1904. Both of these disturbed the habitat and permanently changed the landscape. Since the 1970s, commercial enterprises of dredging for subtidal green-lipped mussels has been destroying these habitats.

    The destruction has continued into my lifetime. For example, in the dramatic 2021 floods , my friends bach slid down a hill. A shocking destruction of a home filled with memories. But the hidden impact of mud slides is far more devastating. Mudslides cause excessive amounts of brown sediment to be displaced from the land, settling in the Sounds and leading to extensive physical disturbance to vulnerable habitats.

    Image by Author- Commercial Mussels Farms

    But why so brown? Once Europeans arrived the Sounds continued to change. By the 1970s pine plantations had become widespread and clear felling had begun. Harvested and existing forest makes up about 18% of the land surface in the Marlborough Sounds but contributes to around 65% of landslides in 2021 and 2022 (Hart, 2023). Over the last 50 years sediment accumulation rates skyrocketed and continue to remain elevated. This is seen clearly in the Havelock estuary, which increased soft mud habitat by 34 ha from 2001 to 2014. Steep indigenous forested areas also receive this rainfall but are unrepresented in the slip data.

    The idea of ecosystem-based management (EBM) is also promoted by Urlich and Handley as a way of improving the catchment management. The suggested aim for Marlborough Sounds would be to restore ecological functions so that biodiversity can be maintained. Marine protection is an important part of EBM in New Zealand. It helps to protect remaining high quality habitat and can help with the recovery of more diverse habitats. With proper management maybe one day we will be able to see the return of more mussel beds and marine mammals.

    Is New Zealand really ‘Clean and Green’? Maybe on the surface. But what is happening to habitats in places like the tranquil depths of the Marlborough Sounds? The factors impacting marine habitats are often not well understood. Urlich and Handley suggest that the Marlborough Sounds could rather be referred to ‘brown and down’. This is partially due to the fragmented nature of marine management, where various institutions operate at different scales under diverse legislation.

    Image by Author – My campsite “bach”

    Urlich and Handley highlight that the current marine protection of the Sounds is inadequate as there is only one fully protected reserve. The management of habitats outside this reserve has become an ongoing legal issue. Since the 1880s, calls for additional marine protection within the Sounds has been disregarded. Conservation effort in the Marlborough Sounds is extremely challenging. This study highlights the urgent need for transformative changes in the Marlborough Sounds. It is suggested that the EBM needs to focus on managing seabed disturbance, reducing sedimentation and including Matauranga Maori ecosystem-based management. The EBM has the opportunity to change the narrative back to clean and green from ‘brown and down’ by providing innovative management (Urlich & Handley, 2020).

    Now, when I go out in the Marlborough Sounds, where I was once catching multiple snapper, I am now spending days catching absolutely nothing. With hindsight I need to ask myself: was I part of the problem? Recreational overfishing has contributed to a decline in species.

    Additionally, where once I was surrounded by deep blue sea, now it is often a murky mix. It is time for Marlburians, and New Zealanders as a whole, to take responsibility. We don’t want a collapsing, deteriorating ecosystem. We want an ecosystem that thrives. We want to restore ecological resilience. We want generations to come and sit on remote beaches in the Sounds, benefiting from a thriving ecosystem.

    This article was prepared by Applied Science Postgraduate Diploma student Hannah Smit as part of the ECOL608 Research Methods Class. 

    Urlich. S.C., Handley. S.J. (2020). From ‘Clean and Green’ to ‘Brown and Down’: A synthesis of historical changes to biodiversity and marine ecosystems in the Marlborough Sounds New Zealand. Ocean and Coastal Management. https://www.sciencedirect.com/science/article/pii/S0964569120302593 

    Hart, M. (2023). Human activity a ‘dominant factor’ in Marlborough Sounds Slips. https://www.rnz.co.nz/news/ldr/494507/human-activity-a-dominant-factor-in-marlborough-sounds-slips 

  • Climate change and biodiversity: predicting impacts of the sixth mass extinction

    It is widely known that some 66 million years ago an asteroid hit the Earth, contributing to mass destruction and extinctions, most popularly of the dinosaurs. But did you also know that a very common animal class, birds, are direct relatives to avian dinosaurs? They are literally the only dinosaur descendants. The American Museum of Natural History sheds a light on this, and also names some non-dinosaur animals that persisted through the asteroid impact.

    While tough, thick-skinned crocodiles and alligators surviving may not come as a surprise; frogs, lizards, and some mammals living through the Chicxulub asteroid (with a diameter of 10 to 15 km) impacting with the Earth surely is impressive! If they hadn’t made it through who knows if we would be here today? Those survivors are the origin of our current biodiversity.

    Sadly, this biodiversity is now threatened by one of its own. Many species are going extinct because of us humans. We overuse finite resources, pollute and destroy natural environments to build cities, malls and farms, import invasive species that out compete native ones, … The list goes on.

    There is one really important factor to add here: climate change. By burning fossil fuels, such as coal, gas, and oil, we release gigantic amounts of CO2 into the atmosphere: 37.55 billion metric tons in 2023 alone. The CO2 and other greenhouse gases produced block the escape of heat from the Earth, and our atmosphere becomes warmer. Not only does it become warmer globally, but extreme weather events, such as floods, droughts and storms, become more common, and sea levels rise due to expanding oceans, as well as glacial and polar ice melting.

    Climate change already has a major impact on our planet’s biodiversity. It affects 1,688 threatened or near-threatened species listed in the IUCN red list, a categorisation of the threat status of species, and has been ranked the 7th most important “biodiversity killer“.

    Concepts central to climate change causes and consequences. CC BY-SA, author: typographyimages (pixabay.com)

    Steps are being taken to slow climate change on an international scale, though they haven’t been too successful so far. Governments issue restrictions on emissions produced by industries, promote the use of public transport, and invest in renewable energy production. In 2015, 196 countries signed the Paris Agreement. This created an international plan of action to limit global warming to 1.5°C above the average global temperature in pre-industrial times.

    Even though these measures are being taken, it is likely that climate change will continue to increase in importance for the biodiversity crisis. Measures to limit greenhouse gas emissions will have a delayed impact on the global climate. Thus, the effect of our current emissions will only become visible in 10-20 years‘ time, and in the coming decades, climate change will intensify as a result of past emissions.

    As this is the case, we need to think about what it means for the Earth’s biodiversity. One of the most famous examples of the impacts of climate change on species are polar bears (Ursus maritimus). They only live in the Arctic, which is warming twice as fast as any other region of the world. There, polar bears live and hunt for seals on the ice shelves. Due to higher temperatures, the ice melts and the bears quite literally lose their home and their hunting territory, easily becoming undernourished and sick. To add insult to injury, Arctic warming makes the huge oil and gas fields under the ice more accessible, so that some countries and companies have started exploiting the Arctic. As Greta Thunberg would say, “How dare you?“.

    Polar bears are just one example to illustrate how a species is affected by climate change. Of course, its impacts vary between ecosystems and species, and a polar bear has different challenges to an alpine plant or desert mammal.

    Polar Bear. Creative Commons, author: Andrea Weith.
    Polar Bear eating a seal. CC BY-SA, author: Andrea Weith.

    It has become common for biologists to make predictions on how a species will react to climate change. Historically, only the current climatic conditions of a species’ home range were used to simulate how that range could shift with climate change. Those predictions are then used to inform conservation decisions, which is why it is important that they are as accurate as possible.

    Unfortunately, those conservative models lack a lot of information. If we think back to the polar bears, losing its habitat and hunting range hugely impacts the species, but other associated factors also will influence how they fare in the future. For example, it is predicted that the higher energetic costs of hunting due to climate change will impact female reproduction, and reduce the number and size of healthy litters. Modelling a population with its current demography (its reproductive, survival, and mortality rates), can lead to unrealistic projections, because it doesn’t account for possible future changes to it.

    A study by Urban and multiple colleagues, including Lincoln University’s William Godsoe, looked at ways to improve the accuracy of biodiversity predictions in the face of climate change. They found that including just six biological factors would drastically improve the accuracy of models. Data on the demography of the species, its interaction with other species, its evolution and responses to environmental changes can strongly affect modelling results. So can information on how good it is at dispersing (spreading) as well as its physiology (bodily functions). However, though it may sound easy to include those factors, we lack this data for most species. It is always a challenge trying to make predictions more accurate but lacking data to do so.

    A few strategies can be used to make up for this lack of data. For example, one could focus on modelling the future of keystone species, those that have a more important impact on their environment than others do. Or, researchers could focus on species that are supposedly more sensitive to climate change than others, because if we protect those, others likely also would benefit.

    Unfortunately, with our current knowledge, it is mostly a guessing game to know which species will survive the burden of climate change that we put on the Earth. Though progress has been made, and more integrative predictive models suggested, we still have many questions to answer. Which will be the modern equivalent of birds to the dinosaurs? Or of the crocodiles, reptiles and few mammals that survived the Chicxulub?

    Though predictions always have uncertainty, trying to make the models better by including more information is really important to help us better protect our rich biodiversity!

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

    M. C. Urban et al. (2016) Improving the forecast for biodiversity under climate change. Science Vol. 353, Issue 6304, aad8466. DOI:10.1126/science.aad8466

  • 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.

  • 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.

  • Thistle do me: a fussy biocontrol beetle

    My mother makes a great liver and bacon. Like many cooks who have spent decades on a sheep farm she is also a dab hand with a great mutton roast, scones, and sponge cakes. She can also preserve fruit at a moments notice. The highest compliment I every received for my own infrequent cooking attempts was from my son when I made some excellent gravy – “Well, he is Nanny’s son” he explained. Family feasts around birthdays and Christmas are common at my mother’s house.

    Edith’s fish pie

    One curious dish that makes an appearance amongst the roast veggies and mint sauce is a dish of fish pie. It’s not a typical part of most peoples’ ‘event dining’ but it is a regular for us in amongst the more high flying hams and legs of lamb. Mum’s humble fish pie is tasty, with lots of eggs and white sauce, and the right amount of rice and corn. More impressively, my sons, my nieces and nephews also love it.

    When someone needs a perk up, they’ve been unwell, or they are passing through on their way to a cold, old student flat, a bowl of Nanny’s fish pie will arrive. When there are lots of different options on a laden table, there is always room on your plate for the fish pie.

    Family gathering, three brothers, empty fish pie dish in centre!

    I can understand how I like it, I’ve been eating it all of my life. I guess it is the same for the grandchildren. It’s a constant and comforting food. I’m sure that every family probably has a similar dish.

    How ingrained are food preferences? Do we build them up over a lifetime of experience or do we arrive with inherited preferences? Perhaps a bit of both? It can make a difference.

    Thistles, from the Cardueae tribe, have been introduced into New Zealand, mostly by mistake as passengers with more useful seeds. Like many other species, thistles have done well here and have established in large numbers and with wide distributions. One of the worst is the Californian thistle (Cirsium arvense), close relative of a nearly as successful invader, and a little more photogenic, Scotch thistle (Cirsium vulgare).

    There have been many attempts to control the spread of these thistles with varying, but generally unsuccessful, outcomes. Ideally, it is great to have a solution that can work without too much effort on our part. A successful biocontrol agent can fit that prescription.

    The green thistle beetle (Cassida rubiginosa) forages and lays eggs for their larvae to grow on species from the Cardueae tribe. This creates problems for health and survival of these plants. Excellent, a solution to our prickly problem!

    Cirsium

    Not so fast. Cardueae is a large group (over 2400 species with many natives in New Zealand). The last thing that we need is a beetle that chomps up lots of the species that we are trying to protect. We also don’t want a beetle that gets distracted by eating other species when it should be eating the target. We’ve been there and done that (see the mustelids brought into NZ to eat the rabbits! Oops). We need to know that this beetle is a little more fussy in its likes.

    A Lincoln-based group, including Jon Sullivan from Pest-management and Conservation, have tested the preferences of the green thistle beetle. They have published in Pest Management Science. They selected 16 different plant species from the Cardueae tribe. Beetles were given the chance to eat each species either with no choice (plonk the beetles on a plant and see what they do) or choice (allow them to select between any pair that is presented to them).

    Crucially, the evolutionary relationships were known between the different plant species. Ideally we want the beetles to only eat thistle species of interest and not just anything vaguely similar (just those that are closely related).

    Green thistle beetle samples in Lincoln University Entomology Research Museum.

    When given no choice the beetles tended to make the best of what was offered. When you are really hungry then that marmalade is edible even if you don’t like it! Give the beetle a choice, however, and they go for the species that is most closely related to the Cirsium species. In fact this was such a strong preference that the researchers were able to conclude that the green thistle beetle is very unlikely to become a problem for anything other than the thistles that we want to control.

    The green thistle beetles are born with preferences for the type of plant that they want to eat and to lay their larvae in. These preferences allow them to adapt and specialise more fully to these plant species. New Zealand does not have any native Cirsium, or other closely related species. So the beetle can go forth and munch to their hearts’ content.

    So, was I born with a hankering for mum’s fish pie? Well it is an old family recipe, so the preference for it probably has passed down through our lineage, probably as something that we re-learn every generation. Now if I get some grandchildren, I will have to make sure that they are exposed to fish pie at an early age!

    Adrian Paterson is a lecturer in Pest-Management and Conservation at Lincoln University. He has a lot of preferences that he would like to explain!

  • 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!

  • 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

  • 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!

  • Seed coating: fungi protect maize from disease

    Did you know that seeds can wear coats, just like people? Different kinds of coats can be added to seeds to protect them for improved cultivation. How do seed-coatings work and what are the benefits for seeds wearing coats? There are several distinct strengths of seed coating. You will know a lot more about seed-coating, and a recent discovery that could be applied in maize seeds, after reading throughout this page.

    Recently, Federico Rivas-Franco, with colleages at Lincoln University and researchers around the world, discovered the benefits of coating maize seed with a kind of entomopathogenic fungi (Metarhizium species). Entomopathogenic is a technical word meaning insect killing, so this is a fungus that infects and kills insects. By adding a Metarhizium coating to maize seed, Federico found that maize plants grow taller than the untreated plants, when those plants are in the presence of the plant pathogenic fungus, Fusarium graminearum. That was a useful surprise!

    What’s more, the Metarhizium hyphae (the growing threads of the fungus) were observed growing on and in root tissues in all the Metarhizium treated maize with the coating. This showed that Metarhizium can live together with maize roots and had a consistent effect on defending maize plants from underground pests and plant pathogens (like Fusarium graminearum).

    Fusarium ear rot on maize
    Fusarium ear rot on maize.
    Image CC BY-NC-SA 2.0 by Thomas Lumpkin

    Many of you may be asking, what is Fusarium graminearum? It is a causative agent of several serious plant diseases. Fusarium graminearum can cause a devastating disaster on maize and lead to huge yield losses.

    Maize seeds, roots, stems and ears can all be easily infected by this fungal pathogen, which means maize plants are susceptible to Fusarium infections throughout the cultivation period. More terribly, not only maize, but also wheat, barley and rice can be infested by Fusarium. It is quite annoying, right? It can be expensive for farmers. What if people and stock eat the contaminated crops? The answer is they will get ill, and the symptoms including vomiting, stomach ache and so on. Fusarium infected maize can not be sold as food, so farmers need a solution to protect their crop from this nasty fungus.

    Metarhizium species are a kind of fungus that is generally used to biocontrol insect pests. However, the biocontrol ability of Metarhizium not only works for insects but also against plant pathogens like Fusarium. That’s quite the superpower!

    In 1870s, Metarhizium was first extracted and identified by a Russia scientist Élie Metchnikoff (Илья Ильич Мечников in Russian). He found that there were hypha growing from dead beetles. Initially, the hypha was white, then turned green, and then a darker green. After molecular techniques were introduced at the end of 20th century, new species of Metarhizium species have continued to be identified.

    How does Metarhizium combine with seed coats? In fact, it is microsclerotia, which is a resistant structure grown by the fungus, that is added into seed coats. Over the past decade, it has been discovered that entomopathogenic fungi are able to produce high concentrations of microsclerotia when grown in liquid media.

    Microsclerotia are desiccation tolerant and have excellent storage stability. More importantly, they are capable of producing high quantities of infective conidia (asexual spores) after rehydration. All these attributes make microsclerotia an excellent agent to be used in seed coating.

    Besides preventing plant diseases and pests, different seed coatings can also make seeds grow healthier and improve cold resistance (drought & moisture resistance as well). That’s because commercial seed coatings are composite products made up of combinations of insecticides, fungicides, compound fertilizers, trace elements, plant growth regulators or more other chemical or physical components. What’s more, same size and shape of coated seeds make it much easier for mechanical sowing.

    After using seed coatings, farmers don’t need to use as many insecticides and fungicides to protect the emerging young plants. This reduces the pollution in the environment and the insecticide (or fungicide) resistance of the plant.

    This research demonstrated the excellent potential for adding Metarhizium to commercial seed coatings for maize. We have seen the good outcomes in the experimental field. Let’s wait and see the next step for figuring out how best to do this in commercial production.

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