It’s Halloween today. Although ‘trick or treating’ has started to catch on over the last couple of decades, Halloween has never been that big a deal here in NZ. Perhaps it’s because it happens in spring when everything is greening up, new life abounds around us, and we are starting to appreciate the lengthening days and warmth. In the northern hemisphere it is the opposite and perhaps lends itself to the sinister, the thinning of the veil between worlds, the slide into the difficult time of the year.
Halloween – a time for ghouls and ghosts.
Most obviously, Halloween is a time for horror movies and themes. Scary images show up on our screens and theatres and aim to frighten us. I’ve often thought that horror does not capture Halloween that well. Halloween is more about fey magics, creatures of legend appearing to drive uncanny bargains, the sense of the other, and perhaps a sense of dread. Horror seems like a small part of this.
To be fair, I am not a horror fan. I am certainly not a gore and blood person. I enjoyed the old Hammer Horror films, was scared by “The exorcist”, and scarred by “The fly” (the old black and white version – “Help me…”). But I have stayed clear of slasher films and probably haven’t seen a full-on horror for, well, for a long time.
What are people horrified by at Halloween? Mostly it is ghouls, witches, zombies, vampires, English rugby referees, and ghosts. But it seems to me that there are plenty of other things to be horrified about.
What’s down that path….? Opportunity or threat?
Cate Macinnis-Ng and a host of authors, including Will Godsoe from Lincoln, have published a paper in the Journal of the Royal Society of New Zealand. In this they look at the potential threats and opportunities with the ongoing change in climate. The neat angle here is that they take perspectives from many different people and apply an ecological method, a horizon-scanning approach, to come up with ten for each.
Most of the benefits revolve around the application of new technologies and the chance for major positive societal changes. The negatives are much more specific, more disease outbreaks, dealing with heat waves, increasing black swan events and so on. It is not difficult to read this and feel a real sense of alarm for the future.
So, if you want some real dread this Halloween day, then this is an article to read. Perhaps under your bed covers with the torch. There are no bumps in the night, no jump cuts, no creepy faces in mirrors (although I guess NZ is a bit like a cabin in the woods).
But there is plenty of dread and horror.
Adrian Paterson is a lecturer at the Department of Pest-management and Conservation, Lincoln University.
In my home country, Germany, we have cut down every bit of primeval forest. We hunted aurochs, brown bears, wolves, lynx and even beavers to extinction between the 17th and 19th centuries. After messing it all up like that, we now dare to tell other countries, that still hold on to their forests and wildlife, what to do with their nature.
“Don’t hunt those animals you used to hunt sustainably for centuries; we think they are so charismatic”. Currently, wolves are slowly coming back to Germany, and immediately people (successfully) changed laws to permit their shooting if they prey on sheep because it is “not bearable” to live in close coexistence with wild animals like that. Apparently, wolves don’t belong to Germany anymore because…yeah, because what? Because humans live here?
Now close your eyes and imagine you are a subsistence farmer. Oops, don’t close them, rather, continue reading! You can still imagine, though! Every day you’re working hard taking care of all the veggies and crops you planted to feed your family. One day you look up, and what you see is a massive giant, almost as tall as your house. That giant has destroyed everything you ever planted.
This perception of wild Africa has influenced our approach to mitigating HEI. A common attempt is to build physical barriers, such as fences, to separate humans and elephants, believing they could protect both parties. However, elephants are unbelievably strong and intelligent creatures, and they easily overcome these obstacles, leaving farmers caught in a perpetual battle to safeguard their livelihoods.
I have personally witnessed elephants knocking over trees onto “elephant-proof” electric fences to get to the other side. No fence can hold back a herd of determined elephants. Fences, therefore, cannot be the only solution when both humans and elephants need to get their food from the same land. It doesn’t stop with crop and infrastructure damage, though; Humans and elephants die through HEI. Elephants are killing around 500 humans per year and humans return the favour.
After bothering you with way too much bad news, at least I can tell you that science offers a glimmer of hope! Picture a team of brilliant minds huddled around computer screens, armed with data and determination. With powerful tools with mystical names like Agent-based modelling (ABM) and Geographic Information Systems (GIS), ecologists are unravelling the complexities of HEI to help us understand human-elephant interactions better. With these tools, the researchers can simulate scenarios and explore the factors determining conflict incidents, to develop effective measures to reduce the conflicts and to mitigate poaching. The models are needed because, due to plenty of ethical problems, these kinds of experiments could not be conducted in real life.
In their study from 2021, Abel Mamboleo, Crile Doscher, and Adrian Paterson, from Lincoln University, simulated 18 scenarios, considering things like human population, elephant population, rivers, conservation corridors, and protected areas. They evaluated their impact on different HEI incidents, such as crop damage, human deaths, elephant deaths, and hidden impacts. The term “hidden impacts” refers to indirect consequences of HEI and includes fear restricting movements, missing school, or resulting health issues. For example, their “elephant-effects scenario (ES)” evaluated the effects of varying elephant populations on HEI, the “human-effects scenario (HES)” evaluated the effects of varying human populations on HEI, and the “environment-effects scenario” evaluated the effect of varying environmental parameters (distances to rivers, protected areas and corridors) on HEI.
Using their models, the scientists identified hidden impacts of HEI (e.g. fear and resulting health issues or restricted movements depending on elephants) as the most challenging incidents to mitigate. Interestingly, maintaining a greater distance from rivers seemed to effectively reduce those hidden impacts. Now who would have thought that?
Their model also indicated that most incidents of elephant crop damage occur within 1 km from rivers. Therefore, according to the model, it is possible to lower the risk of your crops being eaten and trampled by a grey giant by planting them further away from rivers (Yeah, good news!). Among the incidents studied, human deaths were found to be the easiest to reduce (more good news!). Fifteen out of the 18 scenarios lead to significantly fewer human deaths.
Distancing human activities from rivers, and creating conservation corridors and protected areas, seem to be an effective mitigation strategy. However, challenges remain. Reducing the deaths of elephants seems to be one of the most difficult tasks, with only six out of the 18 scenarios showing significantly fewer dead elephants. The number of elephant deaths was reduced in some scenarios, such as a so-called “ENS-River-Protect-Corridor”, in which the scientists modelled farms to be 7000 m away from rivers, protected areas and wildlife corridors.
While no single scenario that the scientists played through was able to completely eliminate all incidents, their modelling provided valuable insights and recommendations for potential strategies to reduce HEI. With their models, the researchers showed that HEI is influenced by many different factors beyond the pure numbers of humans and elephants. Geographical and environmental features, such as rivers, protected areas, and corridors, and socioeconomic activities, also play crucial roles. With the approach of creating safe distances between human activities and critical areas, the researchers found practical strategies to minimize the deaths of both humans and elephants.
The study’s findings, therefore, highlight the need to address the spatial relationship between humans and elephants and promote responsible settlement planning. Successful strategies for mitigating HEI require a holistic approach that balances the needs of both humans and elephants and prioritizes a healthy elephant population as well as the well-being of affected human communities.
It is important to emphasize that models are just a tool, implementing solutions still needs to be done by our big, juicy human brains. For example, in all scenarios, the model suggested to just lower the population size of humans and/or elephants to mitigate HEI. Fewer humans, fewer elephants: fewer human-elephant interactions. Of course, both options are far away from an ethical or recommendable solution. If the elephant density is extremely high, relocating them to other areas could be a (very complicated and expensive) option.
Wait a minute! Hey, German politicians, how come you haven’t thought about reducing the population size of humans in areas where the wolves are coming back? I heard many of us would love to live in New Zealand anyway. What about providing a free one-way ticket to New Zealand for every revengeful German sheep farmer who wants to kill wolves as a compensation measure?
Mamboleo, A. A., Doscher, C., & Paterson, A. (2021). A computational modelling approach to human-elephant interactions in the Bunda District, Tanzania. Ecological Modelling, 443, 109449. (https://doi.org/10.1016/j.ecolmodel.2021.109449)
As a Kiwi, when I hear the word ‘pest’ my mind instantly goes to possums, stoats, rats and cats. These are some of the invasive mammals which are killing so many of our native species, most of which cannot be found anywhere else in the world. These lethal pests have turned us into killers as well; we promote and stand by numerous lethal methods for pest management, without batting an eyelid. Whilst some are made uneasy by the thought of trapping, poisoning or hunting these creatures, we still employ these measures as second nature.
When talking about pest management in the past, I never quite understood the shock or disapproval from visitors from overseas. They get a certain look on their faces when they hear what we do to these mammals, many of which they are trying to protect at home. It seems to them that we have become somewhat apathetic to the lives of these creatures and accustomed to having blood on our hands in the name of pest management.
The way that I look at it, along with many other New Zealanders, is that I feel a strong sense of responsibility for protecting our native birds, lizards and plants. I do accept that these pests are simply trying to survive, on an island archipelago that they didn’t choose to live on.
Some parts of the world, have a much larger agricultural pest issue: elephants. Hearing this, helped me to understand what others feel when we talk about pests in New Zealand. How can an elephant, such a majestic creature, be considered a pest?
Of course, an agricultural pest differs in definition to the introduced conservation pests that we have in New Zealand, although reactions to these pests seem to be the same. In retaliation to the damage caused to local livelihoods or personal safety, some people have been reported to purposefully remove native elephant habitats or even employ lethal methods to control the “problem elephants”. I am now the one in shock, although in the grand scheme of things it’s not so dissimilar to our pest control strategies.
Abel Mamboleo, as part of his PhD research at Lincoln University, asked the question, published in the Journal of Biodiversity & Endangered Species, of whether elephants were really the most disastrous agricultural pest animals or are they actually the agents of ecological restoration. He reviewed multiple studies and publications to obtain crucial information about elephants, agricultural pests and ecological restoration. All of this helped guide him towards the answer to this big question: are elephants a pest or an ecological blessing? He also wanted to summarise the existing knowledge to help both conservationists and local people create appropriate plans for sustainable management.
Human-elephant conflicts arise through any interactions between our two species that have negative impacts on social, economic or cultural life, on elephants, or on the environment. The most common feature of these interactions is crop-raiding. As human populations increase, our demand for land, water and food also increases. Consequently, historical elephant habitat is being infiltrated by human activities through agricultural development, limiting elephant habitats to small “ecological islands”. This means their usual dispersal routes are restricted and the competition for resources with humans increases.
So, what happens when the natural habitat and resources of elephants are taken away? They search for food elsewhere, with the most abundant source being crops on surrounding farms. Elephants actually prefer agricultural crops to wild plants because they are more palatable, nutritious and readily available. For this reason, local people have labelled elephants as the most disastrous agricultural pests, because of the damage from elephants that they sustain. But is this a fair statement?
Elephants were compared to the criteria an animal must fit to be considered a pest. These criteria include any animal that feeds on crops, damages buildings or stored food, injures people and kills livestock. When looking at it this way, yes, elephants by definition are pests. They damage stored and field crops, which ultimately affects human food security during drought seasons. However, to be labelled the most disastrous agricultural pest seems a bit extreme. In fact, for this to be the reality they must be causing massive economic damage to crops and property; more than other pests.
While they do cause some local damage, Mamboleo found that they only cause moderate damage when compared to other pests. The damage inflicted by wild pigs actually far outweighs that of elephants and puts them in first place for the most disastrous agricultural pests. Elephants even sit behind rodents, European starlings, red billed quelea and desert locusts when looking at the line-up for the worst pest offenders in these areas. While it is true that elephants can inflict extensive damage, it is still significantly less than other pests. For local people, it is hard to see it this way as they have entire fields of crops decimated by these giants.
People are seeing persistent crop damage and associating this with pest behaviour. Because their farms often closely border protected elephant habitats, it means people are seeing more severe crop-raiding and they’re seeing it more frequently. While on the other hand, the elephants just see more food. Naturally, the elephants are getting the blame and inheriting this new title; from a local perspective it is an obvious response.
On the other hand, elephants are considered as agents of ecological restoration. Much like secret agents, they work inconspicuously to repair and re-establish ecosystem services that may have been damaged by human activities. A successful act of ecological restoration must be effective, efficient and engaging. This is otherwise known as the “triple E” principle, which serves as the guidelines for evaluating environmental restoration processes.
Elephants are effective because their natural and physical abilities provide all sorts of environmental benefits to humans and other wildlife. They also have the ability to restructure their environments, sometimes opening up thick vegetation and helping their herbivore neighbours in the process.
Elephants are also efficient because of their high level of intelligence and behaviours; they are able to perform productive ecosystem rehabilitation activities in a consistent and timely manner. Usually this is without the support of human intervention. Elephants have been branded “ecosystem engineers” or “mega-gardeners” because of their role in dispersing seeds, helping both wildlife and humans. Through ecological restoration, these elephants are replenishing cultural resources and socioeconomic conditions for humans and allowing re-connection with nature. Some would call that engaging. This ecosystem restoration allows humans and other wildlife to reuse otherwise damaged ecosystems.
So what is the answer to whether elephants are the most disastrous agricultural pests or actually the agents of ecological restoration? This needs to be looked at from two separate viewpoints. Yes, they are pests, but they are not the most disastrous. And, yes, they are agents of ecological restoration. But they are both occurring simultaneously, depending on the perspective you view it. Can’t they be both?
Although I was vaguely aware of dung beetles and their role in the ecosystem, I finally became interested in them while participating in giraffe research in South Africa. I’ll never forget the time when I was finishing up my giraffe work for the day and I stopped to watch a couple of dung beetles who were squabbling over a single ball of dung (poop). What I had perceived to be a relatively gentle disagreement escalated quickly when I watched one demolish the other with a long-time favourite move from the World Wrestling Foundation, the Brainbuster. You know the one.
Dung beetles play an essential role in the environment. However, they fly a bit under the radar, which is why they are often called nature’s “unsung heroes.” There are over 100 species of dung beetle, each choosing one of three strategies: rolling, tunneling, or dwelling in dung. Not only do they eat and live in animal dung, but they increase the freak by reproducing in it and burying it. This ensures their offspring have plenty of food for when they hatch.
As gross as it is, this burying behavior strongly limits the growth of vertebrate parasites, which is tremendously helpful to the rest of the ecosystem. They help remove animal dung from the surface environment with incredible efficiency and speed. In some places, the beetles can eliminate a pile of dung in less than 10 minutes, where the ground would otherwise be carpeted with it.
Dung beetles are very widespread, found in many different habitats across all continents except Antarctica. Like many species, dung beetles appear to be harmed by the break-up of natural environments. This fragmentation reduces the size of undisturbed, or core, habitat in the centre and creates isolated habitat patches. The environment along the edge of a habitat is usually quite different from the core. In forests, for example, it’s typically windier and sunnier at the edge of the forest than in the centre.
Edges are not only susceptible to environmental challenges, but also to human impacts. They are more vulnerable to fire, as well as illegal harvesting or collecting of plants or animals by humans, simply because they are more easily accessible. Some of these impacts along the edges don’t stay localized, but can radiate into the core habitat as well.
Edges are in fact an important habitat, because they support species that like transitions between different habitats. However, as humans continue to break up large habitats, with roads or communities for example, the amount of edge habitat increases, while core habitat shrinks. This challenges the animals that rely on core habitat. Additionally, the edges of habitats typically support fewer species than the core. We don’t want to consistently change habitats around the world to ones that support similar and fewer species.
Buffer zones are areas around a sensitive, often legally protected, environment that are typically managed to reduce edge impacts on the borders of a sensitive area. Sometimes buffer zones have methods to exclude humans or livestock, such as fences. Sometimes they are simply designated areas without active protection measures. Relatively little is understood about how effective buffer zones actually are for some species.
Back to dung beetles, we typically see fewer individuals and a less diverse group of dung beetles along habitat edges than in the core, because they are a group that tends to be quite affected by human activities. For example, because they are in constant contact with dung, they are exposed to pesticides that livestock ingest, which has been causing population declines. But how do buffer zones impact dung beetle diversity and density along the edge of protected habitats?
Andrew Barnes and his colleagues, including the late Rowan Emberson from Lincoln University, decided to find out. The montane rainforests in Sub-Saharan Africa are shrinking rapidly, largely due to deforestation for agriculture and grazing. There is also nearby habitat decline that often comes with agriculture. The Ngel Nyaki forest reserve in Nigeria is a heavily fragmented area. To test how dung beetles would respond to increasing edge effects, the researchers applied experimental habitat restoration treatments to certain areas along the edges. For the restoration, researchers excluded livestock with fencing, created and maintained firebreaks to help block fire, and allowed passive natural regrowth of the floral community. This combined restoration occurred in 200 metre buffer zones over the course of three years.
The impact of these buffer zones was remarkable. In the forest next to the restoration area, the dung beetle population size increased by over 50% compared to the unrestored areas. Perhaps more important was the difference between dung beetle populations in the edge and habitats. Before the restoration, there were many more species of dung beetles in the habitat core and relatively few in the edge. After the restoration, that difference disappeared, meaning that the buffer zones successfully mitigated the challenges that are typical of edges for dung beetles. The restoration also led to the return of certain species that had previously locally disappeared in the degraded habitat.
These changes are incredibly pronounced and occurred after only three years and with small levels of restoration. While firebreaks do require active maintenance, it is encouraging that even relatively minor land-use changes around protected areas can make a world of difference for many species. Relatively few studies have been completed about the effectiveness of buffer zones, so this is a single, but vital, drop in a much larger pot of conservation decisions.
After all, we want all dung beetle species to survive, no matter how gross or freaky, to tidy up after vertebrates and perhaps to get more inspiration for wrestling moves.
Mickey Mouse and Scabbers the Rat, are causing biodiversity loss in Aotearoa, New Zealand. They are committing crimes against some of our most endangered wildlife and arriving uninvited to the party. Protecting our taonga falls into the hands of conservationists and wildlife managers. New research plays a vital role in protecting our precious taonga.
Menacing mouse – a little creature creating a big problem. Photo by Nils Fleischeuer (CC BY-NC)
Would you be surprised to read that mice (Mus musculus) have been recorded eating live albatross (300 times their size)? I sure was! How could a little mouse possibly kill a bird known for having the largest wingspan in the world? Sadly, lots of albatross die from mouse predation every year. When mice aren’t eating albatross, they dine on many species of insects, chicks, eggs and lizards.
If mice are so terrible, what about rats? There are three species of rat in Aotearoa, the Norway rat Rattus norvegicus, Black rat Rattus rattus and the Polynesian rat Rattus exulans. They are all bad news – they kill adult birds, chicks, snails and insects. They also compete for food that should be there for our native fauna.
Due to the negative impacts of these rodents, and other introduced predators, many of New Zealand’s most critically endangered fauna are whisked away to predator-free off-shore islands. Some are protected behind expensive predator-resistant fences. PHEW, job completed, right? Not so fast!
Despite eviction notices, Micky and Scabbers can wriggle their way back into our protected areas. Maybe it’s a quick hop along a fallen tree that bridges the now not so “predator-resistant” fence or a long swim to an off-shore island. When they do appear, we need to have proven tools in the toolbox to deal with them. One of the tools to control them is cereal poison bait.
These baits are like your breakfast cereal in that they are made from similar ingredients – apart from the poison! Picture this: you reach for your new box of breakfast cereal in the morning and notice an open, very much neglected, box of cereal sitting at the back of your pantry. It’s been there for so long you can’t remember opening it (or you’ve just been ignoring it for many months). It smells stale and has gone slightly soggy, so you bin it, knowing full well that it will taste nasty.
A good rat is a dead rat! Photo by Jacqui Geux, iNaturalist NZ, (CC-BY)
Bait stations are used to protect the bait from the rain. However, just like you with your open box of stale cereal, mice and rats also have preferences when it comes to eating their cereal. The longer that bait is stored inside bait stations, the less palatable it is to rodents, the less they eat and the longer it continues to sit and weather.
To make things worse, the bait stations are often irregularly serviced, so wildlife managers need a bait that stays palatable to mice and rats for as long as possible. This is an issue on remote predator-free islands and fenced predator-resistant sanctuaries that have difficult access and limited funds. Stale or mouldy bait in particular will not control rodents if they aren’t even going to eat it.
If only there was a way to prevent baits from absorbing moisture and going mouldy – keeping the bait fresh for longer so that mice and rats were more likely to eat it when they come across it …
This is where researchers at Lincoln University (NZ), James Ross and colleagues, had an idea to coat the baits in a material that will do just these things. Also the material will not reduce the palatability of the baits to mice and rats. To test this idea, they created an experiment using two coatings, Polyvinyl butyral (PVB) and Shellac. Shellac is already used as a food glaze and as a coating to mask the bitter taste of Paracetamol/Acetaminophen. Shellac is also fully biodegradable, which makes it environmentally friendly.
The coatings were tested using four combinations of the aforementioned substances. First, they had to ensure the new coatings didn’t reduce the palatability compared to uncoated baits. If mice and rats do not eat the new bait coatings, it would be a waste of time to test them further. If Whitakers coated your favourite chocolate bar in something strange, you might take one bite and decide that the new “sardines & whipped cream” coated chocolate bar was not your vibe.
An easy pill to swallow – A Panadol tablet, commonly coated in Shellac. (CC BY-NC-SA 2.0) Photo by venana, Flickr.
The researchers also had to measure whether coated pellets remained palatable after extended environmental exposure because this is highly likely how mice and rats will find the baits in the real world. In the experiment the coatings were placed on the food the captive rats and mice were fed on. Mice, and more so rats, are neophobic (afraid of new things). So placing new food in their cages might affect the results in such a way that the researchers are measuring the wrong thing. Putting the coatings on their food means their wary responses will be minimised, since they eat rodent pellets every day. After the mice and rats had munched their way through their favourite snacks, the bowls were weighed, and the results were in – Shellac for the win.
There were differences between the bait coating combinations; Shellac was the most palatable, it performed the best for both mice and rats. Shellac out preformed the PVB coating and the mix of PVB/Shellac. This experiment demonstrated that mice and rats are picky eaters and highlights the importance of testing the different coating types. Coatings, although no thicker than 500 micrometers (really thin), will affect how much mice and rats will eat. Ironic given that mice and rats will eat out of a trash can – now we know they are fussily searching for the “best rubbish”.
This research is a step in the right direction for conservation in Aotearoa. I call it a small win for the native fauna. With Shellac showing promising signs, researchers and wildlife managers can test the new bait coatings in the field. Wild Mickey and Scabbers can try out some of the mould free, ‘fresh as can be’ Shellac bait. So next time Mickey and Scabbers arrive uninvited to the party, it may be the last thing they do.
This article was prepared by Master of Pest Management student Nils Fleischeuer as part of the ECOL608 Research Methods in Ecology course.
My armour is like tenfold shields, my teeth are swords, my claws spears, the shock of my tail is a thunderbolt, my wings a hurricane, and my breath death!” Smaug from The Hobbit, by JRR Tolkien.
Wyrms or worms? It’s probably not the introduction you’d expect from your typical friendly neighbourhood earthworm, but as it turns out, they’re not as harmless as they may seem. Could it be that introduced specimens are actually taking over the home-soils of worms native to Aotearoa New Zealand?
An invasion as ruthless as that of Smaug (you know, the “specially greedy, strong and wicked worm” described in JRR Tolkiens “The Hobbit”), when he drives the dwarves from their tunnels beneath the Lonely Mountain? Well, maybe.
New Zealand is actually one of the countries with the highest number of endemic earthworms (“endemic” meaning they exist nowhere else in the world). It has over 200 different species, all of them in the Megascolescidae family.
They thrive in soils of native vegetation but rarely survive in land used for agricultural purposes. For this reason, it’s fair to assume that the land-use-change, caused first by the Māori, then the Europeans, was not appreciated by the worms living in that ground. With the introduction of agriculture and pastures, it didn’t take long for native earthworms to disappear, only hanging on in areas that were still covered with the original vegetation.
Twenty-three species of European earthworms (from the Lumbricidae family) were introduced. They quickly took over the changed habitats and ecological functions from their New Zealand worm-cousins, which themselves continued to live in exile, deep within the realms of untouched soils (this, and further information can be found here).
As described here, European species have been moving from agricultural land into adjacent native vegetation. We know from other parts of the world, like the US, that the presence of invading exotic earthworms causes changes in the soil, such as nutrient levels. This has effects on the entire ecosystem as well as on the native worms living there.
One of the first studies to look at the co-existence of the exotic and native earthworm species in New Zealand was done by researchers from Lincoln University in 2016. The study was called “Response of endemic and exotic earthworm communities to ecological restoration“. The goal of the project was to find out if endemic earthworm species would come back to recolonise areas where native vegetation has been restored. The study looked at two sites, located on the east and on the west coasts of New Zealand’s South Island. On one of them, plant restoration had been happening for over 30 years, on the other for 8 years.
The team of researchers excavated soil from each site and hand-sorted out all worms present. In the lab, they were carefully identified as either endemic or exotic. After the slimy work was done, the following conclusion was reached: the populations of endemic worms increases alongside the length of the restoration period. In the meantime, the population of exotics remained more or less stable.
In restored sites exotic and endemic earthworms can co-exist in native soil. However, exotics may make life more difficult for New Zealand’s endemic worms, perhaps by making the soil less favourable for them, or just eating up the yummy leaf-debris. Further studies are urgently needed! However, despite these negative implications, are exotic earthworms just another invasive species in New Zealand, something we should get rid of to save the natives?
The endemic worms are definitely not as feisty as JRR Tolkiens dwarves (I imagine them perhaps with more of a sedate and gentle character, more hobbit-like really, lots of second breakfasts and idling around the Shire). They most likely aren’t planning a revolt to reconquer their homeland that has been turned into pastures and cropland.
Today, agriculture plays an immense role in New Zealand, and the European worms have become indispensable to the farmland areas, as as they provide many benefits in terms of waste recycling, soil fertility and crop productivity. This has encouraged efforts to continue increasing the dispersion of exotic earthworms in New Zealand’s agricultural land in recent years. It seems the exotic worms, like Smaug, are already hoarding the “gold” of the New Zealand’s fertile lowland agricultural soils and have begun expanding their sovereignty into the depths of the native land.
Our native worms may need their own King Under the Mountain to come and save the day!
This article was prepared by international exchange postgraduate student Nicola Wegmayr as part of the ECOL608 Research Methods in Ecology course.
The study this blog is based on can be read here. It is the source of most of the factual knowledge that has been included.
Boyer, S., Kim, Y.-N., Bowie, M., Lefort, M.-C., and Dickinson, N. (2016). Response of endemic and exotic earthworm communities to ecological restoration. Restoration Ecology, 24(6):717-721. https://dx.doi.org/10.1111/rec.12416
Would you steal a loaf of bread to feed your hungry family? Fair enough. What about a couple of grapes to save yourself the misery of wasting nine dollars on sour fruit?
“Try ‘em before I buy ‘em,” is my dad’s usual response to that question, as he pops grapes from three different bags one-by-one into his mouth. A red one here, a green one there, maybe even a dark purple if the season is right. In spite of earnest pleadings from embarrassed children and grocery store placards, there would be no purchase of grapes unless a thorough investigation of both quality and taste had been completed.
As weird as it may sound, it turns out my dad is not alone in his grocery store grape grabbing. A quick google search yields numerous articles, blogs, polls and debates on the topic. A more recent article used an extensively rigorous survey of 40 people on Facebook to tackle the question, with results showing that half of respondents advocated for, and actively participated in, grape sampling while shopping. As for the other half? Some seemed to side with this NZ Herald article which refers to grape samplers as both thieves and stealers, while others suggested that this type of behaviour is a “hanging offense”. As a conservation biologist, I am not typically one for philosophical debates, so I’ll leave the ethics of grape sampling and capital punishment up for you to decide.
Unfortunately, a jump back into the conservation sphere does not make me immune to grape stealing dramatics. As it turns out, nature, just like the produce aisle of my parent’s local grocery store, is home to its own collection of fruity felons. Among those felons is the European starling. You may know starlings for their incredible vocal range, beautiful coloration, or the massive flocks (or mumurations) they sometimes form (check them out if you haven’t). But to winemakers in New Zealand, starlings may be more well-known for being “vicious” and “wasters of fruit.” Unfortunately the problem that starlings cause in vineyards is nothing new, and in fact, it was this very problem that was the inspiration for research at Lincoln University over 20 years ago.
Flashback to 1999 – Napster is in its heyday, Brittney Spears’ “Baby One More Time” is on the radio, and, besides a little bit of Y2K hysteria, life is good. Amidst the excitement of a new millennia, researchers Yuki Fukuda, Graham Hickling, and Chris Frampton from Lincoln University were hard at work trying to solve the problem of the grape stealing starlings. To do so, they tested out two devices designed specifically for scaring birds away from agriculture areas – the Peaceful Pyramid and eye-spot balloons. The Peaceful Pyramid, as the name suggests, was meant to be a “peaceful” alternative to other more aggressive bird deterrents like “noisy gas guns”. It featured a rotating pyramid with mirrored sides, which would reflect rays of sunlight towards incoming birds. The goal was to overload the birds vision to the point that they would no longer have the desire to land and feed. The eyespot balloon was a large balloon with yellow and black patterning designed to mimic the eyes of a large predator.
Both devices were tested at a vineyard in Dunsandel, and at the University vineyard here in Lincoln. Although both were found to scare starlings away from the grapes initially, within a few days almost all the birds had become habituated to both scarers, and they quickly became ineffective. Ultimately, it was determined that both the eyespot balloon and the Peaceful Pyramid were not practical methods for protecting vineyards. Although these researchers did not find a solution to counteract the stealing starlings, they at least helped re-affirm the idea that anti-bird measures need to be thoroughly tested before they are trusted for protection.
In the 24 years since the research at Lincoln was done, there has been no shortage of innovation and testing of bird scaring devices. There has also been some work (here and here) on what birds are doing in the vine-yards. Among the myriad of devices tested, we have seen air cannons, chemical repellents, introduced falcons, large-scale netting, and a few of my favourites, the sci-fi sounding laser scarecrow (unfortunately, this doesn’t look as cool as it sounds), and the RobotFalcon (fortunately, this does look as cool as it sounds).
All of these projects have had the same goal: deter birds from pillaging in agricultural settings. Unfortunately, despite each of these ideas producing some level of protection, they all come with limitations. One is too expensive, another is too time and labour intensive, and some only work in good weather. For many, it seems as if finding a fix-all solution to the crop stealing problem is a fruitless endeavour. If it’s not the Peaceful Pyramid, and it’s not the laser scarecrow, then really what more can we do?
Well, researchers from the University of Sydney think that they have finally found the answer. (If you have been surprised by any of the bird scaring techniques already described, you may want to sit down for what comes next). Like something out of a Stanley Kubrick film, these researchers have employed techniques that they can only describe as “psychological warfare.”
The weapons of war used in this study consist of a stuffed bird attached to a drone (UAV), which is flown through the vineyard whilst playing recorded distress calls of pest birds from a loudspeaker (see image below). The idea is that visual and auditory stimuli on their own are not effective long-term. By tapping into the birds psychology through visual (dead bird) and audio (distress call) cues, they might be able to trigger the birds anti-predator behaviour, and keep them away for good.
Early results show that crop damage in areas patrolled by this flying fearmongerer are up to four times less than areas which used visual scarers alone. It also appears that this system is just as effective as large-scale netting (currently the most effective way to protect grapes), but is much more cost effective. While these results are preliminary, and further testing is still needed, it seems that hope may be flying (and screaming) in on the horizon.
So there you have it. Starting with a couple of grapes at the grocery store, we end with a weapon of war designed to create fear and confusion. While we may not be any closer to answering the debate about grocery store grape sampling, we at least seem closer to solving the grape stealing starling situation. Will psychological warfare finally be the fix-all solution? Perhaps, but only time (and research) will tell.
As for me, I still don’t quite understand what it is about grapes that causes both the starlings and my dad to lose all sense of self-control. Maybe with 24 more years of research, innovation and whatever military tactic comes after psychological warfare, we will finally find that out. I am sure it will be a wild ride.
Citation: Y. Fukuda , C. M. Frampton & G. J. Hickling (2008) Evaluation of two visual birdscarers, the Peaceful Pyramid® and an eye‐spot balloon, in two vineyards, New Zealand Journal of Zoology, 35:3, 217-224, DOI: 10.1080/03014220809510117
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.
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 art and joy of bombing off a bridge. Photo: Gen Toop. Dec, 2022
“Do a manu” “Do a bomb”. On a hot summers day these are the chants that ring out across Aotearoa as packs of kids and adults line up on bridges or climb atop rocks and get ready to jump into a lake or a river. A ‘bomb’ or a ‘manu’ is a very precise manoeuvre that involves jumping from somewhere high, curling into a ball and making the biggest splash you can when you hit the water. Some would argue that a manu involves more technical aerial acrobatics than a simple bomb. Either way, the bomb or the manu is a rite of passage for many New Zealand kids.
But increasingly this treasured national pastime is under threat. The Ministry for the Environment painted a grim picture of waterway health in its recent Our Freshwater report. Nearly half of New Zealand’s lakes are in poor or very poor health. Only two in every hundred lakes are in good or very good health. Many rivers have become so polluted that they are now unsafe for swimming at times. And it is not only humans who can no longer safely swim in some of the country’s rivers. Native freshwater fish are struggling to survive. More than three-quarters of them are threatened with extinction.
The native freshwater birds that depend on rivers, lakes and estuaries, are also in peril. More than two thirds of them are threatened with extinction or at risk of becoming threatened. Introduced predators, like trout and stoats, are one of the main culprits behind the decline in native freshwater fish and bird populations. The degradation of freshwater habitat by pollution is another driver that is pushing these precious species closer to extinction. Cleaning up waterways is important not only for protecting the long-held tradition of doing a ‘manu’, it’s also critical to the protection ngā manu (the birds) of Aotearoa.
Algal Bloom in the Waikirikiri, Selwyn River. Photo Credit: Gen Toop. Jan 2021
Nitrogen pollution is one of the leading causes of the degradation of New Zealand’s freshwater ecosystems. When excess nitrogen on the land seeps down through the soil past the rootzone of plants it can get into the groundwater. From there it can move into the aquifers that many communities and cities get their drinking water from, or it can re-emerge in springs and get into lakes and rivers. Once in those lakes and rivers nitrogen can cause algal blooms, which can suck oxygen out of the water making it difficult for freshwater fish to survive. These algal blooms also make rivers a lot less appealing for jumping into on a hot summers day. Some algae are even toxic and can cause human health issues as well as kill sensitive animals like dogs.
There are lots of different forms of nitrogen, but one of the main forms that leaches in this way is nitrate. The vast bulk of nitrate pollution getting into New Zealand’s freshwater comes from agriculture. That’s mainly because New Zealand’s pastures are loaded up with synthetic nitrogen fertiliser and the urine of the livestock feeding on these pastures has huge amounts of nitrogen in it. When livestock, particularly dairy cows, urinate the plants can’t always use all the nitrogen for their growth and so the excess nitrate can leach into waterways.
Mānuka (Leptospernum scoparium) flowers. Photo Credit: Vil Sandi, Flickr, licensed under CC-BY-ND 2.0
A promising new solution to this nitrate leaching problem has been explored by researchers from Lincoln University, Canterbury University and Plant and Food Research. In 2017, the scientists simulated a dairy cow urinating (not something many of us do in our day jobs) and compared the nitrate leaching rates under three tree species that could be planted into dairy pastures; radiata pine (an exotic species), mānuka (native) and kānuka (native). They found that mānuka and kānuka leached far lower amounts of nitrogen (2 kg/ha) than pine (53 kg/ha).
Speaking about the project Dr Juergen Esperschuetz, the lead researcher from Lincoln university said, “These results show mānuka and kānuka could be even more effective at protecting water systems than anyone expected.”
Intentionally planting trees into pasture where animals continue to graze is a farming system called silvopasture. Silvo is derived from the latin word for forest and pasture, well we all know what that is. Silvopasture is not just about shelterbelts, windbreaks, and riparian buffers, systems which relegate trees to the margins of a farm. Instead, silvopasture systems often plant trees into the paddock itself. It has been said that silvopasture, and other agroforestry systems like it, represent a shift away from monocultural production and towards an agricultural system that more closely mimics natural forest ecosystems. Mānuka and kānuka are native trees to Aotearoa so incorporating them into dairy pastures also provides a way to bring more native biodiversity back into farming landscapes.
The researchers also found that soils under the mānuka and kānuka emit far less nitrous oxide, with the mānuka soils emitting the least of the three. Nitrous oxide is an extremely potent greenhouse gas, it is long lived and in Aotearoa, the vast bulk of nitrous oxide emissions come from livestock farming. So planting mānuka and kānuka into dairy pastures could also help in the fight against climate change. On top of that, both trees produce high-value products in the form of oils and honey and that could be used to supplement farm income.
Cows grazing in a silvopasture. Photo Credit: Gayle Weaver,pixabay.com, licensed under CCO
Since the publication of this study, other researchers have gone on to use parts of its methodology and draw on its findings in their research. In the Wairarapa, a study done in the field found much lower nitrate levels under manuka than under pasture, corroborating the findings from this glasshouse study done by Dr Esperchuetz and his team. In Spain, researchers also drew on the study when they investigated nitrate leaching risk under walnut silvopasture.
This study has added to the toolkit of options available to help reduce the environmental impact of pastoral farming in Aotearoa. Incorporating mānuka and kānuka trees into pastures will not only bring biodiversity into farming landscapes. Thanks to this research, we now know it will likely help clean up our lakes and rivers too, protecting both ngā manu and the manu now and into the future.
This article was prepared by Master of Science postgraduate student Genevieve Toop as part of the ECOL608 Research Methods in Ecology course.
You can read the full article here: Esperschuetz, J., Balaine, N., Clough, T., Bulman, S., Dickinson, N. M., Horswell, J., & Robinson, B. H. (2017). The potential of L. scoparium, K. robusta and P. radiata to mitigate N-losses in silvopastural systems. Environmental pollution, 225, 12-19.
New Zealand has a huge agricultural industry. It also has a pest problem. I myself have been out to a friends’ farm and was told to “squash a mouse if you see one”! Which I think we can all empathise with to an extent. When the little b*stards are eating your food, they might as well be infesting your wallet.
Image CC-BY-SA Diego Delso on Wikimedia Commons: Elephants and humans live in close contact in Africa
Now, think about scaling that up a couple of levels. You no longer have nuisance, albeit damaging, mice scurrying around your farm shed. Instead you have elephants, in herds of 11+, munching through entire fields and even ripping doors off your grain sheds. Stomping won’t quite suffice here (and may go the other way).
This is an issue that Abel Mamboleo and his PhD supervisors, Chile Doscher and Adrian Paterson, at Lincoln University investigated in their JOJ wildlife and Biology paper in 2020. Instead of the standard numbers, quantities and figures you may expect in a science paper, here they take a slightly alternative approach to the topic. What do people think is happening in their backyards? After all, fear and perceptions are powerful things.
To start with a bit of context – who are we talking about when referring to people? This study interacted with people in the region of Bunda, a very densely populated region in Tanzania. Much of its land is a part of the idyllic Serengeti ecosystem, and boasts an internationally renowned tourism hotspot.
Bunda location within Tanzania – right next to the Serengeti: Image CC-BY-SA Macabe 5387 on Wikimedia commons
These people rely heavily on farming. In fact, 80% of annual income in Bunda comes from this industry. You can imagine how devastating it is to have these creatures, as amazing and majestic as elephants may be, decimate their fields of crops.
Elephants eating crops is not a new story. In fact, there are even somewhat humorous accounts of elephants eating rotten fruit in orchards and getting themselves rather drunk in the process. Thieving behaviour may even be tolerated – these giants are big money for tourism. However, in this particular context, such interactions are becoming more and more problematic. In this area, as the human population grows, human-elephant interactions also increase.
Mamboleo went to this area to ask local people their thoughts about these interactions. Using interviews and questionnaires in local languages to ensure clear messages, they found that 88% of those asked thought these human-elephant interactions were on the increase. Furthermore, 79% of respondents reported these events were most common on farms.
This in and of itself is not necessarily an issue. Local people had described the elephants as generally ‘docile’ and can even be safely approached to within 50 m. In the past, farmers have sometimes been able to simply scare elephants away themselves using traditional techniques, such as patrolling and fencing. Elephant ‘friendliness’ has even been suggested in other parts of Africa, with some suggesting elephants are going as far as to domesticate themselves. However, now, elephants are beginning to ignore these scaring techniques, some becoming bolder and potentially more dangerous.
How is this affecting people?
You can begin to see how conflicts between elephants and humans are likely to grow, with 32% of people thinking that elephants will react to seeing a person by killing them, and guarding crops being a main way for these people to protect their livelihoods. And for another large minority, 42% of those asked, they experienced elephants simply continuing to eat their crops in the presence of humans. Evidently, these people don’t have effective tools to deter elephants and protect their farms.
Extreme measures: what to do next?
We can see how people would be having a hard time with their elephant neighbours here. But what about the elephants?
Elephants are protected in Tanzania. The people of Bunda know this. However, desperate times sometimes call for desperate measures. Therefore, occasionally, when an elephant is raiding crops, people may turn to lethal measures. Whilst few people who were interviewed list this as a response to seeing elephants raiding crops, Mamboleo raises the valid point that this number could be higher. Local people know that there could be consequences of authorities finding that illegal elephant kills had taken place in the Bunda region.
Elephants & mice – really that different? Image by GlobalP from iStock
This may seem like a drastic response. However, killing pests such as rats, rabbits and mice that eat crops in NZ doesn’t seem so drastic, does it? Of course, this is a very different situation – elephants are native to this area, and are endangered and protected. But this comparison does make you realise that wanting to kill the problem can be a fairly universal response.
Mamboleo notes that cheap responses can be turned to in the absence of timely support from conservation authorities…so what can be done about that?
Well, there are some cool things being done across Africa to help with these conflicts. For example, do you know that elephants are scared of bees? Who’d have thought. Some projects actually exist to build bee hives around fences to keep elephants away, and this seems to work pretty well. It also turns out that elephants don’t like spicy food – so chilli can be used in a similar way.
More ideas, such as this would, be very useful to help in these situations. Answering questions such as when are elephants most likely to visit the farms may also be helpful for targeted responses, Mamboleo says.
Knowing how people feel, how they’re responding to the situation, and what they need to do to help them resolve the situation for the best outcomes for people and wildlife is a great first step here. That’s the valuable context needed to now take the next steps and make solutions that will work. Especially when we can’t just stomp on the problem!
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