EcoLincNZ

Category: ecosystem services

  • Creeks spread invasive herbs in New Zealand

    Invasive plants can have a devastating impact on our natural environment.

    What are invasive plants? Put simply, they are non-native plants that spread rapidly within New Zealand and pose a significant threat to ecosystems, agricultural production, or human health. It sounds awful.It is even worse than it sounds.

    Lodgepole pine (Pinus contorta) CC BY by Chris Schnepf, University of Idaho, Bugwood.org

    Invasive plants pose a threat to natural ecosystems as they are often highly competitive compared to native plants. Invasive species also spread rapidly to take over the living space of native plants, alter ecosystem structures, and reduce biodiversity.

    Many exotic plants are invasive, such as lodgepole pine (Pinus contorta) and Scotch thistle (Cirsium vulgare). Invasive plants change the composition of plant communities and affect food webs and ecosystem balance. For example, the introduction of eucalyptus alters soil chemistry and moisture content, affecting the survival of other plants and animals (Mengistu, 2022).

    Invasive plants also impact agriculture and grazing and can cause massive economic damage. Scotch thistle (Cirsium vulgare) can quickly spread and take over farmland, reducing crop yields. Unpalatable invasive plants can compete with pasture grasses, reducing the area of grassland available for grazing and affecting livestock husbandry (Massey Universy).

    Scotch thistle (Cirsium vulgare) CC BY by John Barkla,  

    Some exotic plants are harmful to human healthy, like Giant Hogweed (Heracleum mantegazzianum),  which can cause third-degree burns and even blindness by simply touching it!

    Knowing how invasive plants spread can help us to control them effectively. A study conducted at Lincoln University in 2013 focused on whether creek habitats are a source of spread for these invasive plants.

    Researchers from Lincoln University (Alice Miller and colleagues) studied Hieracium lepidulum (Asteraceae), an invasive herbaceous plant that has proliferated in the South Island in recent decades. It now occurs in a wide range of upland habitats, from improved short tussock grasslands, to intact beech forests, to alpine herbaceous fields. Hieracium is a more shade-tolerant relative of the widespread pasture hawkeed.

    Historical data suggests that Hieracium is common in naturally disturbed habitats, such as stream edges and forest canopy gaps. Alice selected creek catchments in the area with the longest known history of  H. lepidulum invasion in New Zealand:  Craigieburn Forest Park on the eastern side of the Southern Alps, Canterbury, New Zealand. She surveyed 1,144 spots along 17 creek catchments.

    Giant Hogweed (Heracleum mantegazzianum). CBS News

    Alice and colleagues found that creek habitats (e.g., stream edges and disturbed areas) play an important source role in the dispersal of H. lepidulum. These areas tend to be subject to more natural and human-caused disturbances, which provide a suitable growing environment for  H. lepidulum, and contribute to its rapid reproduction and accumulation in these areas.

    The high resource availability and frequency of disturbance at stream edges allow H. lepidulum to colonise and spread rapidly. Disturbed areas, such as forest clearings and trail edges, provide similarly favourable conditions. Stream habitats provide connected linear dispersal paths that allow H. lepidulum to spread rapidly along streams and from there into neighbouring areas.

    The dispersal patterns of H. lepidulum in forests and subalpine areas were found to differ. In forests, the dense canopy and ground vegetation form a natural barrier to the spread of this plant. As a result, the density of H. lepidulum in forests decreases rapidly with increasing distance from creeks, except in areas with higher light availability, such as tree-fall gaps.

    Forested areas near creek edges remain vulnerable to invasion. In contrast, in subalpine habitats, H. lepidulum density declined more gently with increasing distance from creeks. This suggests that these areas are less restricted to seed dispersal corridors and more susceptible to invasion.

    Location of study area with the 17 surveyed creeks in bold and indicated by an asterisk. From Google Map

    The study also found that multiple environmental variables had an effect on H. lepidulum abundance, with dense canopy cover reducing light and inhibiting its growth. Areas closer to stream mouths were usually more frequently disturbed and H. lepidulum abundance was relatively higher. Higher elevation areas pose a challenge to H. lepidulum growth due to harsher climatic conditions, but the invasion is still significant in subalpine areas. Disturbances, such as human activities, increase the chances of reproduction and dispersal of H. lepidulum.

    Alice provided several recommendations for managing and conserving areas affected by H. lepidulum. First, she suggested prioritising efforts to limit the spread of this invasive plant by reducing disturbances in the environment and using biological control methods. Second, she recommended setting up monitoring systems in vulnerable subalpine habitats to detect and control H. lepidulum early and prevent it from forming large populations. Finally, while disturbances are natural in these ecosystems, it is important for managers to consider the additional impact of human activities, such as building roads and trails, which can exacerbate the invasion, especially in subalpine areas where the barriers to invasion are lower.

    Hieracium lepidulum Stenstr. (Asteraceae).CC BY by John Barkla

    Through this study, we have gained valuable insights into the dispersal patterns and environmental impacts of the invasive plant H. lepidulum. This hardy invader tends to thrive along creek margins and in disturbed areas, making these locations hotspots for its spread. It is our responsibility to protect these pristine landscapes from invasive species.

    If you’re hiking in New Zealand’s stunning mountains, keep an eye out for those little H. lepidulum spreading on the sly. Let’s be the guardians of nature and protect this pristine land from these “little invaders” that are taking over our ecosystem.We can help preserve the natural beauty and biodiversity of New Zealand’s ecosystems, ensuring that these “little invaders” do not take over and disrupt the delicate balance of our environment.

    This article was prepared by Master of Pest Management postgraduate student Hao Zhang as part of the ECOL608 Research Methods in Ecology course.

    References:

    Mengistu, B., Amayu, F., Bekele, W., & Dibaba, Z. (2022). Effects of Eucalyptus species plantations and crop land on selected soil properties. Geology, Ecology, and Landscapes, 6(4), 277-285. https://www.tandfonline.com/doi/full/10.1080/24749508.2020.1833627

    Miller, A. L., Wiser, S. K., Sullivan, J. J., & Duncan, R. P. (2015). Creek habitats as sources for the spread of an invasive herb in a New Zealand mountain landscape. New Zealand Journal of Ecology, 39(1), 71-78. https://www.jstor.org/stable/26198696

    massey.ac.nz/about/colleges-schools-and-institutes/college-of-sciences/our-research/themes-and-research-strengths/plant-science-research/new-zealand-weeds-database/scotch-thistle/

    https://www.cbsnews.com/news/giant-hogweed-plant-causes-blindness-third-degree-burns-discovered-in-virginia-other-states/

  • Fire-resisting superpowers in plants

    I don’t know what you like to eat at barbecues, but I like some nice roasted veggies! What I don’t fancy are burned broccoli or charred cauliflower. Who would want to eat that, right? Do you have an idea what causes huge amounts of burnt veggies each year? It’s wildfires!

    Seasoned vegetables,
    by polaristest (Flickr)

    With 8-11% of wildfires globally occurring on agricultural land you can imagine that these cause a lot of unenjoyable vegetables. Agricultural wildfires mostly derive from accidental ignition from machinery use or through the escape of fires initially deliberately lit for management purposes. Because 38% of land worldwide is used for grazing and cropping, there is a lot of potential for fire, which highlights the importance of reducing the fire risk to secure our major food sources.

    We don’t have to go far to realise the significance of this topic, as Canterbury accounts for around 20% of New Zealand’s total farmland, roughly 2,600,000 hectares of land. That is about the size of 3,700,000 rugby fields! Canterbury has a climate characterised by low precipitation and dry winds, good ingredients for an easily flammable outdoor barbecue.

    Local wildfires take away many people’s chance to roast their veggies themselves as well as causing a huge amount of economic and ecological loss. But what if we could use farmland for fire prevention? What if some crops actually had the superpower to fight against wildfires, or at least survive them?

    Canterbury NZ, by Simon (Flickr)

    There is a lot of information on how to plant mindfully, using low-flammability plants to create buffer zones that allow us to keep wildfires under control and stop them from spreading. Those ‘green fire breaks’ were tactically planted after the Port Hill fires in 2017 to prevent history from repeating itself. As green fire breaks can only help reduce the impact of wildfires to some extent, planting smart on farmland might add to the best practice, especially in fire-prone areas like Canterbury.

    That is exactly what was tested in a study by Lincoln University in 2023. Masters student Tanmayi Pagadala, with colleagues Azhar Alam, Tom Maxwell, and Tim Curran, tested 47 different agricultural plants for their flammability superpowers, following a simple recipe.

    Ingredients:
    – 47 different shoots and plants of the following groups: cereal crops, forage crops, fruit trees, grazing forbs, pasture grasses, weeds, pasture legumes, vegetables, and wine grapes.

    Utensils:
    – Infrared laser thermometer
    – Lighter
    – Plant barbecue (“a 44 gallon drum cut in half with a grill on top”) 

    Plant barbecue
    (Image by Hanna Hoeffner)

    Instructions:
    – Heat the grill by turning on the burner (125-199 °C)
    – Place your sample on the grill in a horizontal position and leave for 2 minutes
    – Turn on the blowtorch for 10 seconds to ignite the sample
    – Wait until the plant stops burning

    Following this recipe, one can evaluate the ignition time, the maximum temperature reached, the burning time, and how much of the sample was burned.

    After many days of barbecues, Tanmayi’s team was able to tell which plants have the superpower to resist fires better than others. Fruits and cereal crops had significantly higher flammability compared to vegetables, weeds, winegrapes, forage crops, grazing herbs, pasture grasses and legumes. Or, to make it more understandable, easily flammable crops dry faster, are generally dryer, and retain more dead material. Veggie superheroes were bell peppers, spring onions, and potatoes.

    Tanmayi’s team created “A fire-wise mixed cropping farm system” as a guideline for purposeful planting on farmland. The idea of fire-wise cropping is similar to green fire breaks. Using low-flammability native tree, grass and legume species as boundaries around higher flammable crops. 

    Broccoloid, by CaptainEdawardTeague (deviantart)

    Higher flammability species are then protected from wildfires that start outside of the farmland and also prevent fires started on the farm from spreading to neighbouring properties. While you must consider other factors, like local environmental conditions, economics, and goals like enhancing biodiversity, this approach can add to existing green fire breaks. By redesigning farms, we can utilise the fire-resistant superpowers of some species to safely plant non-super-powered plants and minimise increasing the wildfire risk.

    Even though this research was conducted in New Zealand, many of the species tested are common crops worldwide. Therefore, their superpowers could come in handy in many places with continuously increasing fire risks, putting veggies at the forefront of the fight against wildfires!

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

    Pagadala, T., Alam, M. A., Maxwell, T. M., & Curran, T. J. (2024). Measuring flammability of crops, pastures, fruit trees, and weeds: A novel tool to fight wildfires in agricultural landscapes. Science of the Total Environment, 906, 167489. https://doi.org/10.1016/j.scitotenv.2023.167489

  • Fighting fire with farming: flammability of pastures and crops

    The Port Hills are a highly valued geographical feature of Chirstchurch. Located southeast of the city, they are home to a wide range of activities, including rock climbing and mountain biking, as well as being popular among walkers and joggers. Vegetation throughout the Port Hills is varied, containing a range of tussockland, pine forestry blocks, native scrub, farmed grassland, gorse and broom scrub and small pockets of remnant forest.

    On the 14th of February 2024, over 700 hectares of land was ravaged by wildfire in the Port Hills of Christchurch, New Zealand. Over 80 residents were evacuated, and around 130 firefighters with 12 helicopters were involved. Drought conditions and vegetation structure contributed to this event, but could the damage caused by the blaze have been reduced? Could grazing these hills with livestock have reduced the amount of tall dry grass present which fuelled the fire, or could different pasture or shrub species have helped to reduce the flammability of the Port Hills.

    A recent paper from Lincoln University’s own Tanmayi Pagadala, Azharul Alam, Tim Curran and Tom Maxwell has highlighted the differences in flammability between different pasture, crop, weed and shrub species found commonly on farms throughout Canterbury.

    Marley’s Hill on fire. February 15 2024. (Image CC BY-NC by Jon Sullivan)

    A good range of scientific work is available which has investigated the flammability of various plant species in New Zealand, but this has been mainly focused on species in natural areas (both native and exotic), rather than in agricultural environments. Gorse, eucalypts, pines and long grass are well known to be extremely flammable, so why is it that certain areas of the port hills were allowed to return to their same fuel rich state following the 2017 blaze which destroyed over 1600 hectares? It must be acknowledged that efforts were made to replant some of the previously burnt areas in green firebreaks and others in less flammable native species, which were shown to survive the previous blaze in well-established areas.

    Species that regrow following a fire are often also very flammable (eg. gorse and pine). Unfortunately, a significant proportion of the burned land was in pines for forestry, which has since been replanted and will likely create another significant fire risk for the foreseeable future. Continuing the efforts of plant firebreaks of less flammable tree species throughout the Port Hills, as well as within pine forestry blocks, should not be underestimated.

    Individually these breaks may not appear significant, but a thorough network of them throughout the Port Hills could be exactly what is needed to slow the spread of the next blaze and allow firefighters to gain control sooner. Minimising the presence of long, rank grass could also help to slow the spread of the burn.

    Could additional efforts be made in to reducing the presence of long rank grass through the addition of cattle to grazed areas which would trample and eat this dry plant material? Or perhaps planting more drought tolerant, water-efficient forages which can be grazed down during dry periods to minimise the fuel loading of grasslands could be beneficial.

    Dry, rank grass fuelling the blaze on Christchurch’s Port Hills. (Image CC BY Francis Vallance)

    There is a huge range of flammability in different crop and pasture species common to Canterbury farming systems. Assessments carried out on Lincoln University’s trusty ‘plant BBQ’ tested 47 different plant species and varieties common throughout Canterbury farms (see table below), including cereals, forage crops, fruit crops, forage herbs, forage grasses, forage legumes, vegetable crops, weeds and a range of wine grape varieties.

    Unsurprisingly, the majority of forage and pasture species showed very low flammability, as did some vegetable crops and wine grapes. Cereal crops behaved as expected, showing high flammability as they matured and dried off. Surprisingly, apple trees, pears and raspberries showed a high degree of flammability.

    Table of plant species and their relative flammability assessed by Pagadala and colleagues

    The slope of the Port Hills, and an average annual rainfall of 700 mm, means that using low flammability crops like potatoes or peas is not practical. There are, however, a range of pastoral species that show the potential to be beneficial in reducing the flammability of farmland. Forage crops, herbs, legumes and grasses all showed very low flammability scores, which is due to their high moisture content and quality traits meaning they carry very little dead material (the ideal fuel for fires).

    Knowing these flammability scores in addition to the the drought tolerant traits of species, such as lucerne, cocksfoot, red clover, plantain and chicory, raises the question: why are these species currently not implemented throughout the fire prone Port Hills as a method of reducing fire risk? Yes, these forages will become flammable if they are allowed to turn to a reproductive state. However, their drought tolerance and palatability will allow them to be well grazed during dry periods and not contribute to the fuel loading of hills anywhere near the amount that browntop and other native grasses will.

    Chicory next to native pasture in Taranaki. (© Blake Gunn – used with permission)

    The photos above paint a picture of a potential solution to the Port Hills fire woes. At the very least, an effort should be made to ensure that flammable biomass throughout the Port Hills is minimal. Minimising the presence of flammable species, such as gorse and pines, through manual removal or switching to planting less-flammable alternatives, such as native shrubs, are some potential solutions.

    Preventing the planting of pine plantations near the city and other populated areas seems like another fairly logical solution to reducing the fire risk in populated areas, as does surrounding these potential high-risk areas with low flammability and native shrub species. Another area of focus could be to focus more on the management of cattle and/or sheep to intensively graze the hillsides and ensure that a bank of highly flammable fuel does not build up over time. Intensive grazing will not only prevent grass banks from building up, but the ‘hoof and tooth’ activity from grazing may also prevent other flammable species, such as gorse and broom, from re-establishing.

    Lucerne transforming a Central Otago farm system (© Allister Moorhead – used with permission)

    Functional firebreaks could also be of huge benefit to these hillsides. In areas where tractor access is possible, consideration should be given to the establishment of drought-tolerant, low-flammability species, such as red clover, chicory, or lucerne. These will create ‘green zones’ throughout the hillsides that could slow the spread of the next inevitable fire, especially compared to the current vegetation which is prone to turning to a dry, reproductive state over summer.

    To wrap up, logic suggests that previous fires in 2017 and 2024 on the Port Hills, in combination with the presence of flammable vegetation, make another blaze in the future almost inevitable. The findings from recent research on the flammability of pasture and crop species commonly found on Canterbury farms, combined with modern grazing regimes present a real opportunity to significantly reduce the fire risk on the Port Hills. The use of firebreaks planted with native, low flammability species around high risk areas such as pine forestry blocks, along with the protection of existing pockets of native scrub/forest should also help to reduce the fire risk on the Port Hills.

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

    Reference article:
    Pagadala, T., Alam, M. A., Maxwell, T., & Curran, T. (2023). Measuring flammability of crops, pastures, fruit trees, and weeds: A novel tool to fight wildfires in agricultural landscapes. Science of the total environment, 906(1). https://doi.org/10.1016/j.scitotenv.2023.167489

  • 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