EcoLincNZ

Category: Climate

  • Burning branches — flammability and shoot architecture

    Burning branches — flammability and shoot architecture

    In mid-February 2017, at about ten at night, I walked out to the street outside my south-Christchurch home and took a photo of the hills to the south-east. A large vegetation fire was stretched across the hills, which were lit black and orange, with strips of flames and glowing smoke. The blaze was at least 4 km away, but the blackness flattened the scene, and the fire and smoke seemed above me almost, and growing. You could almost believe the hills themselves would burn down.

    The Port Hills fire approaches the city. Image by Joe Potter Butler.

    I took that photo on the fourth day of the 2017 Port Hills fire. It took more than 60 further days for the fire to be fully extinguished. A life was lost, 1600 ha of land was burned, and nine houses were destroyed. Like many people in Christchurch, I was left wondering, why did it burn so fiercely and for so long? Why did this ridge burn, but not that gully? Why did some trees recover, and send out new shoots, while others perished?

    Along with floods, earthquakes, and other things, fires like the 2017 Port Hills fire are described as “natural disasters”, but how natural was this fire really? Prior to human settlement — which began around 800 years ago — fire in Aotearoa was rare. NZ was mostly covered in relatively moist, old growth forest. Because of this history, few New Zealand plants are fire-adapted. However, in Aotearoa and globally, wildfires are becoming more damaging and more frequent, threatening life, property, and ecosystems.

    Understanding what plant species burn, how they burn, and why, is crucial to understanding and managing fire risk across the modern Aotearoa landscape. A recent paper sought to investigate these questions and was led by Azhar Alam, with Sarah V. Wyse, Hannah L. Buckley, George L. W. Perry, Xinglei Cui, Jon J. Sullivan, Dylan W. Schwilk, and Timothy J. Curran.

    Most studies have assessed flammability (how easily they burn) of plant species by looking at leaf flammability in isolation. Azhar felt that there were limitations to this approach; that on its own leaf flammability didn’t fully capture how a fire really behaves when burning a plant in the real world.

    The authors preferred to assess shoot flammability. “Shoot” here means the young branch and branchlets of a plant, and all the leaves that are attached. The authors felt that — compared to just leaves — shoot flammability would better describe how a plant ignites and burns, and, in particular, better captures canopy flammability.

    This is important. Canopy flammability strongly influences how easily a fire moves from tree to tree or shrub to shrub. If we want to understand — and even predict! — how a fire might move through a stand of pines, gorse or kānuka, compared to a stand of old growth native forest.

    Aftermath on the Port Hills. Image from Adrian Paterson.

    Rather than just burning the shoots of a bunch of plants and recording the relative flammability of the species, the authors were interested in recording the effect of shoot architecture on flammability. “Architecture” here means how many branches and how tightly branched the twigs and leaves of a shoot are. For example, Kapuka has a few, large leaves with little branching, whereas korokio has many, small leaves and lots of thin, interlacing branchlets.

    The authors collected six shoots each from 65 plant species that you commonly find in  Aotearoa forests and gardens, including 35 indigenous species. 

    For each shoot, a number of leaf and shoot architecture traits were recorded. It was these traits that the authors predicted would show a strong relationship to flammability. The leaf traits recorded were:

    size of the leaves (total area),

    thickness of the leaves,

    leaf surface for each gram of leaf mass,

    dryness of the leaves.

    The shoot architecture traits recorded were:

    “branchiness” of the shoots (measured both as how many “main” branches each shoot has, and also how many branches the shoot has when you count all the branches the main branches have, all the branches those branches have, and all the branches those branches have and so on,

    “twiggyness” of the shoots (measured by twig mass per given volume of shoot),

    proportion of flammable mass (fuel) there is in a given volume of shoot,

    The shoots were all burned on a “plant barbecue” and their flammability was recorded.

    But what exactly is flammability? And how do you measure it?  There are four key factors that determine flammability of plant shoots:

    How quickly do shoots ignite? Ignitability.

    How much heat do they release once alight? Combustibility.

    How long do they burn for? Sustainability.

    How much of each shoot is consumed by the fire? Consumability.

    The results of these burning tests were clear. All shoot architecture traits and leaf traits were strongly related to shoot flammability.

    Among the shoot architecture traits, greater “branchiness” was shown to increase a shoot’s ignitability, consumability, and maximum temperature, while a greater amount of flammable mass (fuel) for a given volume of shoot was shown to increase a shoot’s fire sustainability and consumability.

    Fire glow on the Port Hills. Image by Adrian Paterson.

    Of the leaf traits, leaf dryness was key. In fact, leaf dryness increased all aspects of flammability more than any shoot architecture or leaf trait. Leaf thickness decreased flammability across the board.

    While leaf architecture traits were not as significant as leaf dryness in affecting shoot flammability, they were still significant. Demonstrating their importance is crucial for improving the management of fires and fire risk. Plant traits are already used in fire behaviour models to predict what fires will do.

    Including shoot architecture traits in these models has the potential to improve their power and precision. Understanding what a fire is likely to do gives us the power to change what it will do by planting low-flammability tree species to create fire breaks,  or buffering properties with lawn or pavement. This knowledge will save property, ecosystems, and even lives.

    If you drove through Arthur’s Pass, in the South Island this summer gone (2024-25), you probably drove past the charred and blackened beech trees and snow tussocks near Castle Hill; evidence of a fire that burned through 1,000 hectares of scrub, grassland and forest last December. This is a scene we can expect to see more and more in Aotearoa in the coming decades. Improving our ability to anticipate and manage fires and fire behaviour will only grow in importance as we move further into our new climate future.

    This article was prepared by Master of Science student Joe Potter-Butler as part of the ECOL608 Research Methods in Ecology course.









  • 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

  • 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

  • Buried treasure: the hidden gems of alpine peatland

    Growing up, I had a fascination with pirates.

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

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

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

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

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

    But what if hidden gems are not always jewels?

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

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

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

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

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

    Buried treasure, some might say.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  • Small animals show us the value of old natural forests

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

    Link to the research article:

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

    Read more:

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

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

  • Every pyromaniacs dream… the science plant BBQ

    In recent decades, climate change has been a cause for social and environmental transformation. For example, the inclusion of words such as ‘eco-anxiety’ to the Oxford English Dictionary shows the growing apprehension we have about the future of our climate. Next time you are feeling overwhelmed as a result of the environment, you’ll have the perfect word to describe it! The reasoning behind part of this social shift is due to ecological impacts caused by events such as rising sea levels, ocean acidification and wildfire. 

    When I was growing up, we lived on the outskirts of Rangiora. I was 7 years old when I experienced uncontrolled fire for the first time; the boundary trees of a farm I could see from my bedroom window went up in flames. After a couple of hours, and a team of fire fighters, the blaze was put out. This event was minuscule compared to the damage caused by the Port Hills fire in 2017, which burnt 1,660 hectares of land, or 1,646 rugby fields, over a worryingly 66 days.

    The Sugarloaf transmission tower is threatened by multiple fires burning out-of-control in the Port Hills south of Christchurch, New Zealand (Left), Image by Ross Younger from Flicker.
    Orroral Valley Fire viewed from Tuggeranong, Australia (Right), Image by Nick D from Wikimedia Commons.

    More recently, our neighbours across the ditch experienced one of the worst fire events in history. The Australian Bushfires of 2019/20 burnt a whopping 18.626 million hectares of land; equivalent to too many rugby fields to count!

    The impacts of wildfire go beyond immediate destruction. Long term effects include challenges for biodiversity and human health. Additionally, the economic toll of wildfires can be extremely pressing. The Port Hills fire alone cost $7.9 million NZD to suppress; I would hate to think of the cost imposed by the Australian Bushfires. Throughout these events, astounding acts of courage were witnessed, whilst land, infrastructure and, regrettably, lives were lost; but could these events have been prevented or the severity of damage lessened? 

    Though recent fires in New Zealand may not be as severe as those witnessed overseas, further destructive fire events are looming. Future conditions likely to be more common in much of New Zealand are hotter temperatures, lower rainfall and windier conditions: a recipe for a fiery landscape. One of the key factors that impacts the scale and intensity of fires is vegetation and their corresponding fuel loads. For example, a plant with a low moisture content and high dead material percentage will, in theory, pose a higher risk if fire were present. However, little research in New Zealand, or worldwide, has put this to the test empirically. 

    Sarah Wyse from the University of Canterbury and her team of scientists acknowledged this knowledge gap and took it as an opportunity. “A quantitative assessment of shoot flammability for 60 tree and shrub species supports rankings based on expert opinion” was published in the Journal of Wildland Fire in 2016. The aim of this paper was to quantify the shoot-level flammability of 60 native and exotic plant species found in New Zealand and compare these results with rankings derived from previous studies. 

    Plant barbeque in action! Image by Georgina Woods

    One of the key pieces of equipment required for this study was a plant barbeque; yes you heard me right. Built out of a 44-gallon drum, the plant barbeque is every pyromaniacs dream. Rather than just burning components of a plant, this study burnt whole shoots (maximum 70 cm long) which preserved much of the plant’s structure. Each sample was left on the grill for 2 minutes to create the same environment as if an approaching wildfire. Once the sample had heated, it received direct flame from a blow torch for 10 seconds. Following this, measurements, such as ignition time, burning time and maximum temperature, were recorded. Overall, this approach creates more realistic wildfire conditions and much more ecologically significant data.

    The study found species such as gorse, manna gum and kūmarahou to be high in flammability whereas species such as whauwhaupaku, hangehange and kotukutuku were low in flammability. These findings have contributed to paving the way for the development of mitigation tools, such as green firebreaks. Green firebreaks are strips of vegetation comprised of plant species that are low in flammability. This reduces the spread of fire, making our landscapes more resilient. As well as this, they contribute to encouraging native biodiversity to flourish.  

    This is only the beginning for plant flammability, which has scope for future research. One of the co-authors of this project, Tim Curran from Lincoln University, has a goal to make this data set and future research known worldwide. Further investigation is going to continually contribute to the existing valuable pool of knowledge, tackling the challenges that continue to threaten humankind.

    As we experience the consequences of climate change, it is normal to feel that creeping sense of eco-anxiety, but this research may help you ease those nerves. Knowing more about a problem is always helpful. So, whilst Sarah, Tim and other keen researchers help expand what we know about plant flammability, I’d save your marshmallows for another day; perhaps we won’t end up as a ball of flames after all. 

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

    Citation: Wyse, S. V., Perry, G. L. W., O’Connell, D. M., Holland, P. S., Wright, M. J., Hosted, C. L., Whitelock, S. L., Geary, I. J., Maurin, K. J. L., & Curran, T. J. (2016). A quantitative assessment of shoot flammability for 60 tree and shrub species supports rankings based on expert opinion. International Journal of Wildland Fire, 25(4), 466–477. https://doi.org/10.1071/WF15047

  • The superpowers of NZ moss: Dry shrubland and its moss ground cover

    I love moss.

    I have always loved mosses. They are so cute!

    Moss is green, all kinds of green, every nuance.

    Some of them are leafy, some of them flat, and some look like cushions.

    They make the forest floor look like a fairyland.

    Moss between bricks in front of Ivy Hall, Lincoln University. (Image from Eva Saison)
    Moss surrounded by render, Lincoln University. (Image from Eva Saison)
    Moss growing on Ivy Hall facade, Lincoln University. (Image from Eva Saison)

    Even better than simply being aesthetically pleasing, mosses have superpowers.

    Like Spider-Man, they stick to vertical flat surfaces, decorating walls with adorable green spots. Moss also has another power. I remember walking through the dunes in my hometown of Calais (France), the sound of waves in the background. Suddenly, between the European beachgrass (Ammophilia arenaria) that keeps the sand and dunes in place, I spot a brown patch of dead moss. Dead? Not really. With just a few drops of water on it, the moss revives in a few seconds, turning the brownish-dead area into a bright green patch of life. Just amazing. Tiny dune zombies are coming back to life through water.

    Moss shows off its Spider-man skills on Ivy Hall, Lincoln University. (Image from Eva Saison)
    Dead looking (but not dead at all) moss on a tree. (Image from Eva Saison)

    Consequently, moss brings joy to people, or at least to me. However, what role is moss playing in nature?

    The study conducted by Rebecca Dollery, Mike Bowie, and Nicholas Dickinson in 2022 helps to answer this question. They were particularly focused on the importance of moss ground cover in a dry shrubland area of New Zealand. They found that moss could be represented as a collector that loves to hoard various things.

    First into the hoard is water. Moss absorbs rainwater or humidity from the air. Moss is almost always wet when touched. The water is then used by the moss. The soil benefits from the waterlogged moss cover: in summer, soil is wetter under the moss carpet. The moss acts as a protective layer for the soil against the summer heat, allowing retention of water in the soil. The water is later used by the surrounding plants. In a dry shrubland environment, moss can have a positive effect on other native plants populating the area.

    Second into the hoard are soil nutrients. All plants need them to grow. One of the most important nutrients is nitrogen (N). It can be found in soil and absorbed by the plants in two forms: nitrate (NO3–) and ammonium (NH4+) molecules. With the ground covered by a moss carpet, the quantity of nitrate and ammonium in the soil decreased, up to 75% for the latter. In addition, the thicker the moss, the lower the amount of nitrate. Therefore, moss not only absorbs water but also sequesters essential nutrients. The nitrogen is trapped within the moss.

    This sounds alarming: moss is taking away the necessary food source of all other plants. However, this is not a tragedy for the dry shrubland environment. Indeed, their soil is low in nutrients under normal circumstances. Consequently, the plants growing there are adapted to these conditions. On the contrary and surprisingly, they might even suffer from a large increase in soil nutrients. The moss carpet thus preserves the original composition of the soil, which is also the optimum growing condition for plants native to dry shrublands.

    Third into the hoard are the seeds that fall and are stored within the moss layer. The researchers tested the impact of moss ground cover on the ability of some native species to germinate. Generally, moss cover prevents germination: fewer seeds germinate than on bare ground. The scientists supposed that the seeds did not germinate because they were in the dark, after falling into the depth of the moss layer. This was mostly observed with tauhinu (Pomaderris amoena) and kānuka (Kunzea serotina) (the species name was revised back to Kunzea ericoides in 2023). Both suffered a 60% reduction of their germination capacity.

    The seeds of the common broom (Carmichaelia australis) can germinate in the dark. For this species, the high humidity within the moss could be the reason why seeds germinated up to 88% less often with moss ground cover. Nevertheless, some seeds germinated and became seedlings. Their next step was to have their roots access the soil to absorb nutrients. The scientists observed that more common broom seedlings survived on the bare ground than with ground moss cover. The moss layer probably acted as a barrier between the roots and the soil. Despite that, the seedlings of common broom and tauhinu that germinated with moss were up to 3 times heavier than the ones from bare soil. This indicates that the conditions provided by the moss cover have had a positive impact on their growth.

    Rebecca and the team identified the moss as a plant that loves to stockpile things: first water, then nitrogen, and finally seeds. The various impacts of the collecting moss were in some ways beneficial for the native plants of the dry shrubland ecosystem. They were, however, detrimental towards exotic and invasive weeds. These invasive species suffer from the low nutrients in the soil and the difficulties of germinating within the moss layer. Moss, therefore, participates in the conservation of native plants in the dry shrubland ecosystem.

    A very interesting name can be added to the “things collected by moss” list: carbon (C). Sphagnum moss are one of the main components of peatlands. In these ecosystems more vegetation is growing than is decomposing, thus vegetation, including moss, is gradually accumulated as layers of peat. Furthermore, when plants are growing, they absorb CO2 from the atmosphere, they keep the carbon to form sugar and release oxygen (O2). Therefore, peatlands are trapping carbon in their vegetation, in their moss. Larmola and colleagues (2014) calculated that one-third of the total amount of carbon stocked on land is trapped in peatlands!

    Zoom in on Sphagnum moss. (Kirill Ignatyev, CC BY-NC 2.0, Flickr)

    After all those discoveries, I continue to love and admire moss. I will carry on watching the moss turn green again in the dunes and taking naps on forest moss. Those tiny superheroes decorate my city pavement and walls, promote native plant species in New Zealand’s dry shrublands and trap carbon from the atmosphere, as little fighters against global warming.

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

    Dollery, R., Bowie, M. H., & Dickinson, N. M. (2022). The ecological importance of moss ground cover in dry shrubland restoration within an irrigated agricultural landscape matrix. Ecology and Evolution, 12(4). https://doi.org/10.1002/ece3.8843

    Heenan, P. B., McGlone, M. S., Mitchell, C. M., McCarthy, J. K., & Houliston, G. J. (2023). Genotypic variation, phylogeography, unified species concept, and the ‘grey zone’ of taxonomic uncertainty in kānuka: Recognition of Kunzea ericoides (A.Rich.) Joy Thomps. sens. lat. (Myrtaceae). New Zealand Journal of Botany, 0(0), 1–30. https://doi.org/10.1080/0028825X.2022.2162427

    Larmola, T., Leppänen, S. M., Tuittila, E.-S., Aarva, M., Merilä, P., Fritze, H., & Tiirola, M. (2014). Methanotrophy induces nitrogen fixation during peatland development. Proceedings of the National Academy of Sciences, 111(2), 734–739. https://doi.org/10.1073/pnas.1314284111

  • The handle on the climate change pot

    I live at a student apartment here in Lincoln on campus and the handles of all of our pots are loose. Maybe you know the feeling. It is a problem, but it feels like a problem for the future.

    Recently, I talked to one of my roommates about it: “Let’s find a screwdriver and fix the pots”. But we have no screwdriver at our apartment, so nothing happened. One of these days, while picking up a pot, my pasta will end up on the floor, as the handle came off! We know this moment will come and it will then be a problem. But it probably will not be tomorrow and there are other more pressing matters at hand, like all of the assignments I have to complete over the next two weeks.

    The infamous pots and pans from our flat. No firm handles in sight. Photo: Jess Bardey

    Climate change is our global pot with a loose handle.

    During 2019, multiple councils in Canterbury, New Zealand, issued emergency declarations for climate change, basically saying that our response to climate change has to happen now. There was a global wave of these declarations in 2019, as it felt like a way for local governments to do something against the global problem of climate change. What a climate emergency declaration entails can vary widely, from a vague “climate change is an emergency in our region” to an outline of possible solutions. Looking back over the last three years, the Corona virus response showed us that governments are able to react quickly to a crisis. A reaction that was hoped for in response to the declarations as well.

    Every time we pick the climate change pot up, we can feel its handle rattling and it feels a bit more loose than the last time. We can see the slow loosening of the handle in the ever drier and warmer summers, the high fluctuation in temperature, and the higher frequency and strength of natural catastrophes. With disasters like droughts, floods or wild fires, climate change feels very real and like an emergency. The handle feels like it is falling off right this second and we feel like we should immediately do something about it, for example set it down, grab a screwdriver, so that it does not end in disaster. But we don’t, we pick the pot back up and go on with business as usual, forgetting about the incident until the next time it occurs.

    Climate protesters demand an emergency declaration, Washington DC, 2021
    “Climate Emergency Banner – DC March” by Backbone Campaign, licensed under CC BY 2.0.

    Sylvia Nissen from Lincoln University looked into two of those declarations to understand their impact, or lack thereof, which were issued by Environment Canterbury and the Christchurch City Council. After the declarations were released they were seen as a sign of hope that might lead to some action. In fact nothing really changed even multiple months after the declaration, with one of the councils even supporting a decision that would lead to more carbon emissions. The declaration by Environment Canterbury was issued after their work was inhibited by activists chaining themselves to their building and stopping their water supply, and the Christchurch City Council felt they were under global pressure, following the release of many declarations around the world. The release of these statements was a fast and easy way to appease the public without having to put much work into it. I mean, looking at our rattling pot handles again, talking to my roommate did feel like we did something about the problem, even though we really didn’t.

    Calling climate change an emergency also led to a weird appearance in the declarations, namely that much of them were focused on defining how climate change is different from other emergencies. Canterbury is well acquainted with emergencies over the last 15 years, with earthquakes in Christchurch in 2010 and 2011, followed by fires, floods and droughts in the region. An emergency is defined as a problem that is surprising and unexpected and in need of an immediate solution. Even though the effects of climate change are getting more prevalent each day, we still feel like we can find the screwdriver to fix it tomorrow. However, none of the existing screwdrivers seem to fit, so maybe we need to find a new one, or a new toolbox. Climate change is an intricate, multilayered problem that needs work on many different fronts at the same time. Local authorities often feel as if they need the governments higher up to change something, because they do not have the authority to do so.

    The emergency declarations were used to get the government of New Zealand to release an emergency statement as well. Often in times of emergencies, the authority completely shifts to one entity to make the response efforts more efficient. This is especially concerning in New Zealand as non-emergency situations have often led to suppression and disregard of Māori rights, and a centralization of power might especially lead to excluding Māori advice from councils. In the declarations Māori advisors were often described as only “present”, not giving an indication as to whether their worries were taken into account.

    Looks like a good start to a toolbox. The yellow gives them quite the emergency color. By hehaden, licensed under CC BY-NC 2.0.

    The notion of just giving the solution over to the next higher authority can also be seen as quite concerning, as bottom-up approaches were seen to lead to more realistic and inclusive solutions. And though no local government will be able to find the whole solution, each can provide their own, unique screwdriver to help fill a toolbox that can fix all the different issues, to screw the handle of the climate change pot back on.

    And looking at all the effects climate change already has on our world, is it really still a problem for tomorrow?

    So now I am going to get up and find a screwdriver. Because the loose handles of our pots (including the climate change one) can very quickly become a problem of today.

    This article was prepared by postgraduate student Jess Bardey as part of the ECOL608 Research Methods in Ecology course.