EcoLincNZ

Category: student blog

  • Kiwi calling: when listening is not enough

    I don’t know about your’s, but my mum gets worried when I don’t respond to her phone calls for a few hours. Once, I can’t remember what I was doing, but I didn’t hear the phone ringing. When I finally checked my phone I saw about 17483 missed calls, oops. I can only wonder what went through her mind when I wasn’t responding: she was probably picturing me skydiving, in an ambulance, or lost in the woods during a hike.

    But what if she’d had a more statistical mindset and thought about why I hadn’t responded? Or even better: what if she’d thought about reasons why she could not detect me?

    Ecologists and conservationists consider something similar when analysing data obtained from searching an area for a certain animal species. An animal could be present at a certain site, but still go undetected. First, they have to consider what ecological reasons might have determined where the species was present or absent (for instance, where is there suitable habitat within the considered area). Second, they have to take into account what factors might have influenced the likelihood of actually observing the species (such as the distance from the observer, or the fact that the surveyor may not be skilled enough to recognise the species). These are defined, respectively, as occupancy (which is the same as saying “presence”) and detection probabilities, and can be estimated by using statistical models.

    Occupancy probability and detection probability are described by two different models and both of them will influence what will be observed during a survey. Taking into account that not all the animals will be observed is very important when attempting to accurately assess a species’ presence, which could otherwise be underestimated.

    A young roroa being released as part of the Operation Nest Egg programme. Image by Jon Sullivan on Flickr.

    Peter Jahn, James Ross, Darryl MacKenzie and Laura Molles, in a study published in 2022, wanted to know how accurate acoustic surveys of roroa-great spotted kiwi (Apteryx maxima) were between 2011-2015. During this time, 18 birds were translocated from the Hawdon Valley, in Arthur’s Pass National Park, to the Nina Valley, in Lake Sumner Forest Park, representing one of the initial efforts of the Operation Nest Egg programme. The researchers also wanted to compare kiwi presence before and after 2015, and between the two areas.

    They gathered data from a survey conducted in 2012-2013 by DOC in both the valleys and then repeated the methodology in 2017-2018. The technique they used was passive acoustic monitoring (PAM). PAM is effective when studying elusive species such as kiwi. Automatic recorders were deployed in the two study areas and left there for up to three weeks, activating just before sunset and switching off shortly after sunrise.

    The team analysed the kiwi calls recorded in each of the valleys. The goal was to find a model that would best describe the obtained data, and use it as a base to estimate occupancy and detection probability. Peter Jahn and colleagues wanted to know which factors were important in detecting the kiwi and looked at the study area (Nina and Hawdon Valleys), year, length of the survey night, breeding/non-breeding season, precipitation, wind speed, night length, varying recorder battery capacity.

    Similarly, my mum could have considered the fact that my phone may have been in silent mode, or had no service, or estimated the actual likelihood of me being in an ambulance. All of these factors could have influenced her imperfect detection of me.

    In both the study areas, the detection probability was found to be higher during the breeding season, to increase with longer survey nights and to be influenced by wind speed, rain accumulation and recorder sensitivity. Also, as expected, kiwi presence in the Nina Valley increased after the translocation, as it did in the Hawdon Valley. Moreover, it was found that the number of sites where kiwi calls were recorded increased in 2017-2018 in both the areas and that, in total, many more calls were detected in the Hawdon Valley than in the Nina Valley.

    The Hawdon Valley in Arthur’s Pass National Park. Image CC-BY-NC by Jon Sullivan on Flickr.

    Wait, the number of sites where calls were recorded and the presence of kiwi increased in the Hawdon Valley after kiwi were removed from there? How is that possible? Yeah, that was one surprising finding of the study. In fact, the researchers were expecting that occupancy would decrease after the birds’ removal, but what they found actually suggests that new pairs re-occupied the territories left inhabited by the translocated individuals.

    This is a promising result, because it means that such conservation strategy doesn’t necessarily negatively influence the population from which the individuals are taken. Also, the ongoing pest mammal control in the Hawdon Valley could have balanced the negative effect of the translocation. I guess the only thing left to do now is find out what makes kiwi desire those territories so much that they can’t stay away: maybe they have the most delicious earthworms of New Zealand?

    To conclude, these findings demonstrate that the species is reacting well to this reintroduction programme, considered that kiwi presence increased in the Nina Valley too. Furthermore, this study showed that combining occupancy estimates through statistical models with acoustic monitoring is very useful when studying the outcomes of kiwi’s translocations. However, if you, reader, can’t wait to know more about what happens to our dear kiwi when we move them around, sit back and read Peter Jahn’s PhD thesis: never stop learning.

    Finally, going back to my mum trying to “detect” me: I suggest the probability would increase a lot if she learned to call outside of my usual napping times!

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

    Jahn, P., Ross, J. G., MacKenzie, D. I., & Molles, L. E. (2022). Acoustic monitoring and occupancy analysis: Cost-effective tools in reintroduction programmes for roroa-great spotted kiwi. New Zealand Journal of Ecology, 46(1), 3466.

  • A foreign threat: New Zealand’s Invasive insects

    One of the many great fascinations of New Zealand is the absurd number of bugs found here that are found no where else on Earth. What’s a bug, you might ask? They’re the six-legged creepy crawlies you find everywhere. They are a part of your life, from the obnoxious house fly in your room to the big, bold beetle in the garden! Well, technically, I mislead you with the name bug. Bugs are a single group of piercing-sucking insects; the correct term to describe errant creepy crawlies is insects.

    Aside from being a nuisance in the home, what do New Zealand’s insects do? They provide excellent services to our ecosystem, whether churning up dirt, pollinating flowers, or controlling noxious weeds. They also serve as an essential part of the food web and are a key to the survival of many birds and lizards.

    A friendly, Robust grasshopper says hello! This photo I took in the Mackenzie district shows one of our largest grasshoppers. They’re excellent grazers of lichens and mosses. Historically they provided great nutrition for many birds and lizards.

    Despite their abundance, insects are massively understudied both globally and in New Zealand. We must understand how our insects contribute to our ecosystems and what might happen when new insect species arrive in our country. Species not previously found in New Zealand (nonindigenous creatures) have been a massive threat to New Zealand’s native biodiversity over the past 200 years.

    Of the non-indigenous species in New Zealand, much of the focus has been on mammals, like stoats, and plants, like wilding pines. This work is essential because these sorts of species have huge impacts on our environment and our economy. But what effects do the over 2000 introduced insect species have on New Zealand? A study by Brockerhoff (in 2009) featuring Lincoln University’s Dr Cor Vink, attempts to determine the threat of new insects to New Zealand’s ecosystems.

    The threat of introduced insects was recognised soon after European arrival. From what we know few of these species are capable of affecting native ecosystems aside from the well-studied Vespula wasp.

    The currently accepted view is that new insects do not generally hurt our ecosystems. However, as New Zealand’s ecosystems are often so understudied there is little way for us to measure the effects of new insects on the environment. Across most of the world, the arrival of new insects can be a catastrophe with substantial environmental and economic impacts.

    A photo by Will Frost of a typical Mackenzie Basin floodplain grassland. A habitat type threatened by new species of weevils and the expansion of dairy farming.

    So far New Zealand has avoided such a catastrophic invasion. Brockerhoff (2009) suggests that perhaps our intact native ecosystems repel insect invasions well compared to other parts of the world. While our forests have repelled invaders so far, the threat of climate change may alter the balance in the war of plants and insects.

    Brockerhoff (2009) aimed to investigate the effects of insect invaders across a range of New Zealand’s habitats. It was found that over 200 insects capable of damaging forests have been found in New Zealand but have had minimal impact on our native ecosystems. Several generalist moth species and a passion vine hopper have had minor effects without significant damage. In grasslands, several weevil species have been found all over New Zealand, even as high as 2800 metres, but their impact on the surrounding environment so far seems to be minor. These results suggest that all is well for New Zealand’s ecosystems. However, with rising temperatures creating more optimal conditions for invaders there could be an increase in foreign insect invaders.

    When species reach more significant numbers, their effects can start to worsen. Vespula wasps are well documented for their disruptive effects in beech forests. They feed on honey sap and compete with native birds for this resource. Worse still, these wasps predate on many native insects, some requiring a 90% reduction in Vespula wasps to survive.

    The Argentine ant spreading through New Zealand and is also of grave concern. In large numbers this ant has the ability to displace native ants and often eradicate many other native insects in the soil ecosystem.

    A photo by Will Frost showing a honey-dew beech forest from Craigieburn Forest Park which is threatened by Vespula wasps.

    So far many of the more harmful insect species are isolated to human-altered habitats. And insects which make it to intact ecosystems fail to make an impact. As these insect’s populations build over time and more begin to enter the country as temperatures warm the threat of invasion into native forests may increase.

    Many insects are selective of the plants they consume due to plant defences and palatability. This is true even for generalist insects that specialise on many plants. This likely explains why so far our plants have provided protection from so many would-be insect invaders.

    Honey dew being produced by scale insects. A rich food source for wasps. Photo from Adrian Paterson

    Brockerhoff (2009) suggests that for these reasons the greatest risks to our ecosystems now are from generalist insects, especially those which don’t rely upon plants. Generalist predators, like Vespula wasps, threaten the whole ecosystem’s natural processes. Due to their ability to consume the sugar produced by scale insects. These wasps prey on the majority of native fauna in beech forests to provide food for their young. When in huge abundances the composition of insects in the forest and availability of sugar sap is hugely reduced. If more generalist insect species with no natural predators were to arrive within New Zealand the impacts would be even greater.

    To reduce the threats to our ecosystems in future, introduction of more insects for biocontrol should not be taken lightly. We are fortunate that few exotic insects have been established in New Zealand’s native habitats. However, many of the subtle effects caused by invasive insects are not yet known, more study is needed to grasp how these effects are impacting the ecosystem.

    In the future, climate change and habitat disturbance could allow new insects to arrive and threaten our native ecosystems. We know enough now to say our environment is safe from hugely adverse effects; however, the future is uncertain. Developing a greater understanding of how these creepy crawlies subtly affect our ecosystems is paramount.

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

    Brockerhoff, E. G., Barratt, B. I. P., Beggs, J. R., Fagan, L. L., (Nod) Kay, M.,K., Phillips, C. B., & Vink, C. J. (2010). Impacts of exotic invertebrates on new zealand’s indigenous species and ecosystems. New Zealand Journal of Ecology, Suppl.Special Issue: Feathers to Fur, 34(1), 158-174. https://newzealandecology.org/nzje/2916

  • Fantastic mantids and where to find them 

    This past year I have been reading a lot of papers about mantids because I will be doing my Masters thesis on the New Zealand mantis. They are very interesting animals that fill the niche of a top predator in many habitats.

    New Zealand only has one native species of mantid which is called te whē/rō in te reo Māori. Te whē/rō is a name shared with the stick insect. This relates to a tradition that Māori have where, depending on which of these insect species lands on you, this will indicate which gender your child will be. Maybe New Zealanders could bring it back for some niche (and traditional) gender reveals?

    Image from Ken Vernon

    The New Zealand mantis isn’t the only mantid species in New Zealand though. Since the 1970s we have had a second species in our country. Spreading from Auckland and across the North Island, the South African mantis quickly established itself in New Zealand. This South African invader is also well established in Nelson on the South Island.

    These invasive mantids have caused the decline of our native mantis on the North Island. This impact is likely driven by the female South African mantis that eat our native mantis males. These males follow their noses to the exotic female only to find out that it is a dinner date, and they are on the menu.  

    NZ ootheca (Jon Sullivan)

    The native mantis is more of a gentle species, where the females are unlikely to try and eat their mate. They don’t live for very long, perhaps six months in the wild. Mantids need a way to survive the winter and ootheca (little mantid egg cartons) protect their eggs while they develop. Both mantid species in NZ have ootheca, though they can easily be told apart. The South African mantis has a puffy white ootheca, which looks like a small meringue, while the New Zealand mantis has a brown ootheca that is smaller and more geometric.

    Mike Bowie, and his son Matthew Bowie, looked at where the New Zealand mantis laid their ootheca. Mike recently retired after over 40 years at Lincoln University, working on many native species, including the habits of New Zealand mantids.  

    The Bowies found that the New Zealand mantis preferred kowhai, native broom, lancewood, and cabbage tree, which together had 78% of the oothecae. Over half of the ootheca were found on smaller branches, predominantly non-shaded. They found that these spots were warmer and brighter than other parts of the trees and this would help with development.

    Oothecae were also centred on true north, which works with most New Zealand houses and fences since most properties are also facing true north. Ootheca are attached to houses and fences that face north, maximising their sunlight. This allows developing mantids to grow quickly. 

    The Bowies also found that there was a size difference between ootheca in Lincoln compared to those in Palmerston North. The Lincoln oothecae were significantly larger than the egg cases up north. There could be a few reasons for this and one of them is that a larger size helps them handle the colder temperatures down here. This size difference also allowed the southern population to fit a few more eggs in their ootheca giving them a bit of an advantage.  

    South African ootheca (Jon Sullivan).

    The study shows that our mantis has various adaptions that allow them to survive the New Zealand winters, especially by using the modified habitat we have created in New Zealand. Despite this, the New Zealand mantis is in decline. The South African mantis lay their ootheca in more sheltered spaces and produce oothecae that are larger than the locals, giving them advantages. They can even lay an ootheca without mating and it will hatch successfully.

    Just like those male mantids, we’ll be praying for a happy ending!

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

    Bowie, M. K.; Bowie, Michael H. 2003. Where does the New Zealand praying mantis, Orthodera novaezealandiae (Colenso) (Mantodea: Mantidae), deposit its oothecae? New Zealand Entomologist 26(1): 3–5. (https://doi.org/10.1080/00779962.2003.9722103)

    Further reading:

    https://academic.oup.com/beheco/article/27/3/851/2365697

    https://traviswetland.org.nz/about-travis/scientific-papers/praying-mantis-in-new-zealand/

  • 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.

  • The hotspots are where it’s at if you want to spot a cat: the search for the common leopard

    The Himalayas are an almost mythical place, where mountains loom and the clouds surf down their sides before sliding into the forests below. The songs of rhesus monkeys, palm civets, and the occasional jackal sing out from the thick trees. This landscape is beautiful yet rugged. Travelling through is difficult for our human capabilities, in many cases impossible.

    Now imagine. This is the backdrop you must navigate to discover the number of big cats that live there. To top it all off, your target is the shyest and one of the rarest of them all, the inappropriately named common leopard.

    A common leopard relaxing in the sun
    (Source: Daily Pakistan: Pakistan’s common leopard endangered due to loss of habitat)

    Now, it’s not unusual that scientists doing field research are thrown into difficult situations. You might end up with dangers like Carlos Jared who innocently picked up a frog while doing fieldwork in Brazil, discovering frogs can be venomous. Or you might accidentally glue yourself to a crocodile while attaching a radio transmitter like Agata Staniewicz did (find that and more hilarious field research fails here).

    But when you’ve got a shy animal, add in an impassable landscape, plus the addition of the very real and dangerous threat of bumping into rebels which is, unfortunately, the reality in parts of Pakistan, you’ve really got your work cut out for you.

    This momentous task is one Muhammad Asad, PhD student at Lincoln University, took on as he bravely set off to northern Pakistan. Nobody had done this before and the leopard landscape was mostly unknown. But he was up for the challenge.

    The not-so-common leopard

    Leopards are found all over the world, the most widespread of all land-based carnivores. They’re incredibly adaptable, able to make their homes in all sorts of climates: from the savannas of Africa, the tropical forests of South East Asia, to the freezing mountains of far north Russia. They even make it work when humans move in.

    Their only request, being rather introverted, is that they have lots of space. They’re very territorial, protecting their home range fiercely. But honestly, a bit of peace is a reasonable request!

    Despite this incredible flexibility, common leopard populations are in decline. They’re no longer found in 63-75% of their historic range. The decline in Asia is even bigger, with an 83-87% drop! It’s no surprise that these gorgeous cats are listed as critically endangered.

    The majestic common leopard
    (Source: Daily Pakistan)

    Leopards are facing many different threats. The main ones are:

    • habitat is lost or changed,
    • trees cut down,
    • inbreeding from being cut off from one another,
    • human developments being built near their protected ranges,
    • prey disappearing,
    • poaching,
    • and human-wildlife conflict.

    Clearly, these cats need protection. So, leaving New Zealand and heading back to his native Pakistan, Muhammad took the first step to build a conservation plan; he had to figure out how many leopards there were and where they were found.

    To do this across the entire country would be too big a job. Instead, he focussed on the Gallies and Murree Forest Division in northern Pakistan, lying in the outer Himalayas. Here, leopards are protected under the law. Even so, there are often no checks for this, with hunters easily getting away with it. This is made worse by the slow and sometimes non-existent compensation programmes, programmes designed to reimburse farmers who have lost livestock to a leopard attack. The locals often resent the leopards. But it’s hard to blame them when people, including children, are occasionally attacked and killed.

    Leopards are poached frequently in Pakistan. Cubs are trapped to sell in the illegal pet trade or body parts and skin are taken for sale. Skin, claws, and teeth are sold in north Pakistan.
    (Source: Raj K Raj/Getty Images)

    Estimating the number of leopards in an area is very tricky. They have large territories with very few cats within each area. Figuring out where to look, especially when the landscape has the worst access, is the key to success.

    How to find leopards

    Muhammad and his crew began with a questionnaire survey. They asked people from local communities who lived nearby to fill these out. They asked about losses of livestock, when the attack happened, and the type of injury, for example, bite marks on the neck, missing dogs, or human casualties.

    Based on the information from the locals, they ended up with 63 different sites where they could focus the leopard hunting efforts. A much better start!

    Next, they moved into these sites, peeling their eyes for signs of poop, territorial markings (such as peeing on a tree), and tree scratches. These signs meant one thing; here be leopards.

    With this proof, they set up special cameras, known as camera traps, on either side of the trail, ready to capture the cats on the silver screen.

    They also set up cameras on 5 connecting trails which hadn’t shown any signs of leopard action. These were used to see if they could capture leopards in areas where they had left no signs. As new leopard trails were discovered, the camera traps were moved to snap those too.

    Sampling locations of the camera-traps survey in Gallies Forest (Ayubuia National Park, surrounding Reserved Forest and Guzara Forest), and Murree Forest (Protected, Reserved and Municipal Forest). Country map (top left – green). Study area showing different city boundaries (middle left).
    (Source: From paper)

    A leopard can’t change its spots – a handy identification tool

    You may have heard the proverb that a leopard can’t change its spots. This is supposed to teach us that we all stay true to our nature, even if we pretend we’re different. But it turns out when it comes to leopards it’s 100% true! The coat of a leopard is as unique as our fingerprints. Incredibly useful when you’re a scientist trying to tell the difference between two cats in a grainy photo!

    Their gorgeous spots are a bit like the shape of a rose, giving them the name ‘rosettes’. This means that by matching up the images of the rosettes you can figure out if it’s the same cat. The best place to match things up is on either side of their back legs or the top of their tail.

    Example of an individual being identified using the rosettes on the tail
    (Source: From paper)

    This is trickier than it sounds. The rosettes change shape as the leopard moves. And it can look different depending on the angle it is to the camera. But still, it’s a pretty helpful method to avoid double-counting cats. Double counting would give you a very different population size! You can find out more information on leopard identification techniques here.

    Example of when the spots don’t match up.
    (Source: From paper)

    So, how many are there?

    In 2017 Muhammad estimated there were between 16-24 common leopards in the Gallies and Murree Forest Division. This went down to 7-12 in 2018.

    However, they don’t think the population dropped. In 2018 they got fewer clear images making it harder for them to identify the cats. They think the real number could be closer to 12-18, meaning its range overlaps with the 2017 estimate.

    But, this might not be the case. In 2018, Pakistan was suffering from a drought. Perhaps the leopards had been forced to move out of their territories to look for food. So far there hasn’t been any research on leopard movements in relation to strange weather. This would be an interesting thing for someone to look into (are there any leopard enthusiasts up for the task?).

    Or perhaps this drop is real. Poaching and unreported killings are still huge in Pakistan. Plus, Muhammed and his team did find signs of hunting. So the reason could in fact be nefarious.

    Regardless of the reason, Muhammad estimated there to be 8-12 leopards and 3.5-6.5 leopards per 100 km2 in the Gallies and Murree Forest Division. They also confirmed they lived in the Swat, Dir, and Margalla Hills, even though locals as well as wildlife departments thought they had disappeared.

    These estimates are not 100% accurate. But the team is pretty confident that they are close to the true number. All in all, a great success.

    Mother common leopard and her cub.
    (Source: Daily Pakistan)

    What next?

    Now there’s a basic understanding of how many leopards there are and where they like to hang out, we can start to protect them.

    With this information, we can:

    • Use the leopard hotspots to keep an eye on the population trends and demographic changes over time.
    • Decide on the most important conservation areas. Special attention should be given to the corridors that join areas together to protect the long-term health of the leopard populations.

    For example, Muhammad discovered that 70% of leopards killed for revenge in the Guzara Forest happened outside of the Reserve area, close to the village, and in winter. That tells us we should focus the conservation efforts on the hotspots in the Guzara Forest surrounding the Reserved Forest so that human-leopard conflicts can be reduced.

    There’s still a lot of work ahead for the common leopard in Pakistan. But with Muhammad on the case, their future is looking a little brighter.

    You can read Muhammad’s research in full here: The Un-Common Leopard: presence, distribution and abundance in Gallies and Murree Forest Division, Northern Pakistan

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

    Full citation: Asad M, Waseem M, Ross JG, Paterson AM (2019). The Un-Common Leopard: presence, distribution and abundance in Gallies and Murree Forest Division, Northern Pakistan. Nature Conservation 37. 53-80. https://doi.org/10.3897/natureconservation.37.32748

  • Mātauranga Māori: the way of the past and future?

    During my time studying at Lincoln University I have noticed that there is a lack of Mātauranga Māori in our research and study methods. This lack of recognition for the value of Māori methods is concerning, although this could be related to the high demand for Māori academics throughout the country.

    New Zealand’s culture is unique. Understanding and participating in the Māori culture is a unique experience that is not replicated anywhere else around the world. Incorporating Mātauranga Māori research methods holds the potential to be beneficial for all research projects. There needs to be a clear understanding of Mātauranga Māori and how colonisation has affected Māori connections to their land. Mātauranga Māori is a modern term for the combined knowledge of Polynesian ancestors and the experiences of Māori living in the environment of New Zealand.

    Understanding how to incorporate cultural methods into research holds the potential to generate a greater understanding of unique ecosystems in New Zealand. There are many different methods and systems from Māori culture that can be used within research to help describe and understand the data being collected. Mātauranga Māori is a knowledge system that incorporates a Māori philosophical thought, world view and practice. Kaitiakitanga is described as a place-based customary responsibilities and practices of Māori who have a genealogical history that connects them to the land and it embeds a vital link between Māori and Papatuanuku (Earth Mother).

    Bernard Spragg. NZ

    Science knowledge underpins a large part of our day-to-day lives, and it’s questions encourage us to learn about the world we live in. Indigenous cultures have an advantage (to some degree of course) with their understanding of the land they inhabit, as their ancestors have spent centuries gathering information from medicine, food and historic events that directly relate to the land. Unfortunately, due to the dominance of traditional and classic research methods in science, much of this information has been disregarded and suppressed.

    Amanda Black from Lincoln University, along with lead author Tara McAllister and others, co-wrote a paper (published in 2020) deciphering Mātauranga Māori in New Zealand ecology. Her article discusses the benefits of understanding and incorporating Māori knowledge and practices in research cases. Indigenous knowledge and connections to the land and marine environments offer deep temporal and spatial insights that can reshape our understanding of biodiversity. Such knowledge can also help us to create new pathways to halt or slow the rate of biodiversity loss.

    The use of Mātauranga Māori within research allows us to re-shape our current understanding of the environment and provides improvements to address pressing environmental issues. ‘Two-eyed seeing’ is a metaphor that is used to assist people in conceptualising indigenous and western knowledge systems and to combine them in various ways that provide important insight for research.

    Using this system can enhance ecosystem management throughout New Zealand. For example, assigning legal personhood status to a natural ecosystem (such as when the New Zealand Parliament assigned the Whanganui River legal personhood) aligns with how Māori view themselves – an integral part of the ecosystem. Legal personhood provides a framework where activities of exploitation need to be evaluated against the impacts on the ecological health of the system as a whole.

    The Whanganui River, Kathrin & Stefan Marks

    Ecosystems as legal identities could provide a flexible and durable alternative to the current approach of regarding ecosystems and their natural services as ‘free’, which has led to their gradual decline. This is where the Kaitiakitanga system is important. It is the responsibility of everybody residing within New Zealand to understand how the speed and scale of urban and agricultural landscape change disrupts the relationship between people and their lands. The loss of links to nature has the possibility to damage the health and well-being of urban Māori (and all New Zealanders).

    The recurrent theme of the paper is the importance of co-development and co-creation of research through effective partnerships with Māori. The paper recognises that there is a lack of interaction with Māori regarding research. It also illustrates the need for scientists to move beyond a research process that involves either no or one-off consultation with Māori to a process that acknowledges Māori as Treaty partners.

    Being able to incorporate understandings from multiple knowledge systems is vital for a thorough understanding of the natural world, which is crucial in advancing the science of ecology within New Zealand. Understanding the indigenous knowledge systems/Mātauranga Māori of New Zealand and incorporating it into research priorities will improve the overall findings for researchers as they will have a more informed background of their area of study.

    The author Janie Kersten is a postgraduate student in the Postgraduate Diploma in Applied Science taught at Lincoln University. This article was written as an assessment for ECOL 608 Research Methods in Ecology.

  • 1080 reasons for optimism

    Photo overlooking Mount Summers (Jan 2022). Image by Chida Chapagain.

    It’s good to be optimistic. I have always been hopeful about the future. I lived the first 11 years of my life in a refugee camp. Times were tough, but I knew things could only get better. Even as a child, I knew there was more to this world than what I had experienced.

    Fast forwards a couple of years, and my family and I are living in New Zealand, happier than ever. The first 11 years in Nepal, compared to my last 11 years here in New Zealand, have been extremely different. My life changed for the better.

    Sometimes I wonder what would have happened if my family had moved to America or Australia instead of New Zealand. I often catch myself saying, “maybe my life would have been even better?” Optimism combined with curiosity can be a powerful motivator, leading us to explore the unknown. But we must be realistic with our expectations. Just because we are optimistic about the unknown doesn’t mean it must be true. There will always be challenges and limitations. Nothing is, or will ever be, perfect. 

    The same applies to alternative pest control methods being developed in New Zealand. The pest control toxin 1080 has its concerns, as do alternative methods that have been or are being developed. 1080 is a fully developed method that has been repeatedly shown to control introduced pest mammal populations on a large scale.

    The common brushtail possum (Sept 2010). Photo by Daniela Parra from Flickr.

    While it may not be perfect, it is widely recognised among scientists and conservationists that 1080 is currently the best tool we have for pest control. The use of 1080 is essential in protecting our native flora and fauna. However, we should always be looking to make improvements, but until such progress is made, the use of 1080 must continue. Perhaps you’ve read other things about 1080 and don’t agree. Allow me to explain.

    Bruce Warburton, Penny Fisher, Brian Hopkins, Graham Nugent, and Phil E. Cowan of Manakai Whenua Lanacare Reserach, along with James Ross of Lincoln University, outline the major areas of concern raised by 1080 and summarise the changes that have been made to the use of 1080 to address these concerns.

    The main four concerns related to the use of 1080 have been:

    1. the potential environmental and human health risks,
    2. the limited control over where the bait lands when applied aerially,
    3. the lack of species selectivity, and
    4. the animal welfare impact on target and non-target species.

    They explore the impacts of 1080 use for conservation and bovine tuberculosis (TB) control. They then summarise alternative toxicants and methods for mammal pest control being investigated in New Zealand. Then they address to what extent these alternative methods might be able to address the concerns raised by 1080 opponents. This article may alter your views on 1080.

    1080 is the current best tool we have for our unique fauna!

    Sodium fluoroacetate (1080) has been a recognised pesticide since the early 1940s. 1080 is most frequently mixed into cereal baits for possum and ship rat control. New Zealand is the world’s largest user of 1080. The extensive use of 1080 in New Zealand is made possible by our unique fauna, where we have 35 introduced mammal species and only two native terrestrial mammals (both bats).

    Introduced mammals, such as rats, possums, and stoats, are widespread and have significant impacts on native biodiversity and/or agricultural production. They continue to damage and threaten native and endemic species at unacceptably high rates.

    Māori believe ‘failure to act falls short of our responsibilities to our ancestors, and future generations’. Fortunately, 1080 is a very efficient method for pest control. Monitoring by the Department of Conservation (DOC) before and after aerial 1080 operations targeting possums, rodents, and stoats has repeatedly shown consistent benefits for nesting success in kiwi, kea, kaka, whio, pīwauwau, mohua, and tītitipounamu. O’Donnell and Hoare in 2012 found native bird populations to have doubled after more than 20 years of sustained predator control. 

    North Island Saddleback (Oct 2021). Photo by Geoff Mckay from Flickr.

    Are the ‘concerns’ about 1080 fact or evidence-based?

    There are concerns and opposition to the use of 1080. Some are evidence-based. 1080 does kill non-target species. According to Dave Hansford, about 12% of radio-tagged kea died after aerial 1080 operations. In 1970, there was a ministerial review of the properties, effectiveness, and regulatory control of 1080. The review supported the use of 1080 but also recommended areas for improvement. Most of these recommendations were implemented, but opposition to its use remained.

    In 2006, there was another formal assessment of 1080. Once again, the use of 1080 was permitted. 1080 opponents were still outraged. This triggered another investigation by the Parliamentary Commissioner for the Environment (PCE), who is tasked with providing independent advice to the government. The PCE concluded that “not only should the use of 1080 continue, but that we should use more of it.” Justified concerns about 1080 have been thoroughly reviewed many times, and these reviews have refined the ways in which 1080 is used safely to benefit the NZ environment. The remaining strong opposition to 1080 use by some New Zealanders has required that a lot of time and money being spent on developing, testing, and registering alternatives to 1080. 

    What are these alternative pest control methods?

    There are many alternative methods for pest control. However, many of these are not feasible for our unique situation. For example, shooting is not a viable method for small mammals like mice and rats, and it is too expensive to apply on a large scale. Trapping, similarly is not cost-effective for large-scale operations, especially in the more remote, mountainous parts of New Zealand. Although these methods can complement 1080, they cannot achieve the levels required for effective large-scale conservation. New toxins, including zinc phosphide, sodium nitrate, coumatetrayl, and diphacinone, have also been registered for use. However, none have been developed for aerial use.

    Genetic methods have the potential to drastically reduce the population of mammalian pests. There is a lot of attention on “gene drives”, which are engineered using the CRISPR/Cas9 genome editing technology. The gene drive DNA sequence, typically for reduced fertility, is then interwoven into the genome of an individual organism of the pest species, and every offspring of that individual inherits this modified DNA. One individual with this deleterious gene could potentially lead to complete eradication. This is the most promising alternative to 1080 in terms of cost and efficacy. There is, however, be significant scientific and public scrutiny to be done on this method.

    In the meantime, our birds are continuing to be eaten by pest mammals.

    My final thoughts

    Having lived in both Nepal and New Zealand, I have been able to witness many beautiful birds. Nepal is home to the Himalayan Monal, which is my favourite. I vividly remember chasing this colourful bird around as a child. New Zealand is also home to many beautiful birds. We cherish these birds; they are part of us. However, today, many of them face the risk of extinction.

    I am not an expert in pest control, but, I understand that without pest control, conservation programmes would fail. Reviews after reviews have shown that 1080 is the best current pest control method we have for introduced predatory mammals (possums, mice, rats, stoats, weasels) in New Zealand. Until we have better options, we need to continue using the best tools because our endangered endemic species cannot wait. We are lucky to have a pest control method that has proven to be so effective. It’s good to be optimistic.

    The author Chida Chapagain is a postgraduate student in the Postgraduate Diploma in Applied Science taught at Lincoln University. This article was written as an assessment for ECOL 608 Research Methods in Ecology.

  • Fishing for possum DNA

    When I was a child, I was fixated on animals. In fact, 5-year-old me would go around telling all the primary school mums that I wanted to be a Palaeontologist. This was often met with some strange looks, quite possibly because they didn’t even know what a Palaeontologist was themselves. Since then, I have been less focused on digging up dead animals and more interested in protecting the ones that are still alive.

    In New Zealand, tourism and agriculture are arguably the biggest money-maker industries. People flood from overseas to check out the clean green image being advertised in their home countries for themselves. The ‘Great Walks’ lead tourists through the rugged bush that New Zealand has to offer. Along the way they might even see some of our diverse flora and fauna, of which most can not be found elsewhere on Earth.

    On the other hand, the dairy, sheep and beef industries in New Zealand, earn large amounts of overseas revenue. This all started when Samuel Marsden introduced shorthorn dairy cattle to New Zealand from New South Wales and the rest is history.

    https://www.australiangeographic.com.au/topics/wildlife/2017/04/killer-possums/

    This brings me to the devious, but very cute looking, Brushtail Possum, Trichosurus vulpecula. In Australia, the Brushtail Possum is a protected species. In New Zealand they are a serious threat to our homegrown species. Possums compete with our native bird species for food and inhabit the same areas. These fluff balls are omnivores. In addition to eating the leaves off trees, they rob the nests of birds and eat the chicks and eggs.

    Bovine tuberculosis is a disease that affects many farm animal species. Possums are the biggest carriers of tuberculosis and can infect herds of dairy cows, causing serious illness to the animals and a large vet bill for the farmer. Due to these factors, New Zealand tries incredibly hard to get rid of these furry mammals. One important thing that we need to know is where these possums are present and and in what numbers. For a nocturnal and relatively cryptid species, this is a lot harder to do than simply call a roll!

    The use of trace DNA to monitor animals, such as possums, is a relatively new concept. However, a trial was held in Canterbury where researchers collected DNA from saliva left on WaxTags and Chewcards to determine the number of possums in an area and check whether these individuals were Tuberculosis carriers. From the initial field study, it was found that multiple possums would bite the WaxTag and Chew cards which made it difficult for the lab team to isolate certain animals. A new device to collect data was needed.

    A mechanical collection device was created which would remove the bait after one animal had bitten into it, which protected the saliva and therefore the individual DNA could be distinguished. The device was a bit like a fishing line, catching its prey and then reeling in the DNA! Researchers found that the mechanical device allowed the DNA to be collected and more easily sequenced. They also found that the genetic material was more easily recovered from covered WaxTags than on the uncovered WaxTags.

    Mechanical device created to protect DNA sample on the WaxTag. Image from: A New Non-Invasive Method for Collecting DNA From Small Mammals in the Field, and Its Application in Simultaneous Vector and Disease Monitoring in Brushtail Possums
    Mechanical device created to protect DNA sample on the WaxTag.
    Image from: A New Non-Invasive Method for Collecting DNA From Small Mammals in the Field, and Its Application in Simultaneous Vector and Disease Monitoring in Brushtail Possums

    Cameras used in the field trials picked up that the possums interacted with the new WaxTags, and 87% of the devices were triggered after the first interaction. This is a positive point because in order for a monitoring device to be useful, the target has to interact with it.

    This new way of collecting trace DNA samples was a success. DNA from Brushtail Possums was able to be amplified for genetic identification and was able to detect if diseases were present. The combination of the device being interesting enough for the targets to interact with, and the subsequent DNA extracted being protected until collection, means that it is ever more likely that technology like this can be used for other pest species to determine their disease risk.

    The current study is the first to collect trace amounts of possum DNA and keep it protected from the elements until genetic analysis has taken place. This is a pretty big step for DNA collection methods. However, transmission of infectious diseases by vectors, such as possums, is density dependant. More collection devices need to be installed in these areas being studied to create ‘encounter’ history for individuals to determine population density and to calculate the likeliness for for transmission of these vector carried diseases.

    This research suggests that there are new ways for non-invasive monitoring pest populations. The road to New Zealand being predator free by 2050 is a long one, but is shortened by the impressive new technologies being developed in the pest management space. This technology is key for determining the populations of pests in their area and how likely their livestock are to contracting devastating diseases such as Bovine Tuberculosis.

    Dealing with pests may not be the most fun thing to do week to week, however, determining where populations are and where the risks lie can help experienced personal to more effectively manage pest populations and get New Zealand back to where we should be, mammal predator free.

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

    Emami-Khoyi A, Agnew TW, Adair MG, Murphy EC, Benmazouz I, Monsanto DM, Parbhu SP, Main DC, Le Roux R, Golla TR, Schnelle C, Alizadeh H, Csányi S, Heltai M, Jansen van Vuuren B, Paterson AM, Teske PR and Ross JG (2021) A New Non-invasive Method for Collecting DNA From Small Mammals in the Field, and Its Application in Simultaneous Vector and Disease Monitoring in Brushtail Possums. Front. Environ. Sci. 9:701033. https://doi.org/10.3389/fenvs.2021.701033

  • Māori environmental values and assessments of ecological effects

    A resprouted pūriri tree. Photo/Paula Godfrey, December 2021

    I never imagined as a small child that growing up I’d be an ecologist, deciding the fate of trees we drove past, and maybe one day, the very trees I climbed. One of my favorite trees is a silver ponga (Cyathea dealbata) near our whare (house). The photograph below shows me as an 8-year-old sitting in my ponga tree. For several months a year, I couldn’t climb the ponga while it grew its new fronds. We were strictly not allowed to cause any tree to die without good reason and a blessing from Papatūānuku. As a child, my whānau and I spent a lot of time up trees and exploring the the lush bush of north Auckland.

    Sitting in my favourite ponga, 2002.

    As an ecologist working in botany, I get asked all the time what my favourite tree/plant is, and the answer changes depending on what’s looking particularly beautiful that week. Are the kōwhai (Sophora spp.) flowering? Have the kauri (Agathis australis) got new growth? Have the māhoe (Melicytus ramiflorus) produced another bumper crop? These are the factors that influence my answer.

    Take for example the pūriri tree (Vitex lucens). Pūriri has significant ecological value in its own right and is often my favorite tree. It produces flowers almost all-year round for tuī to feed on. It allows kereru to eat its berries and it even hosts NZ’s largest moth species (the massive green pūriri moths, Aenetus virescens).

    These trees are impossible to age, as the old specimens have hollow trunks and twisted hard wood, making traditional ageing techniques very difficult. It’s thought that pūriri are the longest living plant in NZ. As part of pūriri tree’s life cycle, they typically start looking sick, fall over and ‘resprout’ by producing roots along their trunk that sink into the ground. By doing so they form large areas of canopy from a single trunk, as now their trunk is prostrate. The photo above shows a pūriri tree which has been cut down and resprouted. The hollow trunk is visible on the right of the photo.

    Pūriri holds ecological values but also holds significant tangata whenua values. For me, as a Ngāpuhi (Northland iwi within the pūriri distribution area), I have a strong emotional connection to pūriri that is intertwined with its ecological value. How can that be?

    Well, pūriri is used as an infusion to wash the bodies of our tūpāpaku (deceased) and adorned with pūriri leaves as they decomposed. The bones are later gathered up and scraped clean, then placed within the pūriri tree in a kete. These days, we simply adorn our tūpāpaku with pūriri and lay them to rest within Papatūānuku. This is what my brothers, myself and Māmā did with our Pāpā. Learn more about this practice here.

    Cutting down a pūriri tree is like digging up a church cemetery without exhuming the bodies first, and in many cases, even today, this would happen without notification to the tīpuna (ancestors) of those who lay there.

    Laying Pāpa to rest. I am middle left. Note the pūriri leaves surrounding the body. Photo/ John Malcom, 2006.

    The issue of Māori values and the environment was brought to media attention (again) last year with the new marina works in Pūtiki bay, Waiheke Island, and the 2020 protests over Ihumātao, the historic stonefields in Auckland en-route to become a major housing development. Although Ihumātao was not a specific environmental issue, environment and ecology is undeniably intertwined.

    As an ecologist working for a private consultancy, or even a government organisation, such as Waka Kotahi, or a local council, you’ll come across new developments (or redevelopments) seeking resource consent. To gain resource consent you need to demonstrate as an ecologist that the environment is not going to be degraded, and that post-development you’ll end up with a ‘net ecological gain’. This is called an Assessment of Environmental Effects (AEE).

    There is a recommendation to include tangata whenua rights in AEE’s (as per the Section 8 of the Resource Management Act 1991). In practice they are kept as separate documents, with no cross-over between cultural effects and environmental effects. How can AEE’s integrate tangata whenua rights as part of an ecological assessment and fulfil the principles of the Treaty of Waitangi?

    A sign at the Ihumātao protests. Photo/ RNZ, Dan Cook, March 2019.

    In 1998 Stuart Waddel thought about the same question. He undertook a study to recognise the indigenous rights in AEE’s and how to integrate them. He found that applicants for resource consents have no statutory requirements to contact tangata whenua when proposing a new development, it is only ‘good practice’ to do so. The AEE’s are used to inform the consenting authority (local councils) on the potential effects that the activity will have on the environment. Therefore, the contact with tangata whenua needs to be prior to the AEE being produced, not after. One good example of intergrating tangata whenua into an AEE is on the MacKays to Peka Peka Project by NZTA.

    Recognition of kaitiakitanga (guardianship) in the AEE’s is when it comes to identification of potential environmental impacts as important for achieving better environmental outcomes for all. The environmental values are interconnected with the mauri (essence/life force) of the area, and links spiritual, genealogical, cultural and physical values. Recognition of kaitiakitanga in AEE’s (because it’s respected within tikanga Māori (cultural practice)), cannot be defined by local councils or government as that would mean they are speaking for kaitiakitanga, which is reserved for tangata whenua to speak to.

    Waddel noted that Pākehā and Māori have long held differing views on the values of our environment, which has lead to contentious issues throughout the colonising history of NZ. Māori value the earth as a precious gift and follow strict rules on kaitiakitanga through kaitiaki (looking after) our environment in order to receive the life giving resources it provides. Māori also value different food sources to Pākehā, such as kahikatea berries. Pākehā tend to view the whenua (land) as a resource ripe for exploitation.
    Ensuring that the proposed development area will be able to be sustainably used for future generations and for mahinga kai (food gathering) is a meaningful environmental outcome that demonstrates that the environment will retain its mauri.

    Shaking the kahikatea berries down for eating, 2005.

    It is more important than ever to carry out pre-project consultation with tangata whenua groups (iwi, hapu, rūnanga) and listen to what they have to say. The real environmental outcomes are achieved when the korero (conversation) is received by the development team with a learning mindset, and tangata whenua recommendations are implemented early in the project. If you’re a bit stuck on where to start, the Bay of Plenty Regional Council has a good resource for iwi engagement on their website.

    Iwi engagement in AEE’s are beneficial for all. If AEE’s are done right, those hundred year-old pūriri trees would be here to stay and not replaced with a car park. If cultural considerations were implemented decades ago, we would have a much more natural environment, greater climate change resilience and many more trees to climb in our neighbourhoods.

    If you want to gain a deeper understanding of kaitiakitanga, I highly recommend reading the book Braiding Sweetgrass by Robin Wall Kimmerer who shares a Native American perspective which is similar to te ao Māori worldviews.

    Citation: Waddel, S. R. (1998). Restoring Kaitiakitanga: evaluating the recognition of indigenous rights in assessment of environmental effects (Doctoral dissertation, Lincoln University).

    The author Paula Godfrey is a postgraduate student in the Postgraduate Diploma in Applied Science taught at Lincoln University. This article was written as an assessment for ECOL 608 Research Methods in Ecology.

  • Nosy predators check out the competition

    Growing up in New Zealand, I had a great passion for animals. Viewing everything through a child’s eyes, I believed that all wildlife should be free to thrive anywhere they wanted. Today I see the realities of the world were all animals are cherished, but some are out of place and others are vulnerable. I am not alone in realising the endangerment and damage that pest species can cause to our native species. This awareness has me seeking to understand the appropriateness of eliminating certain species from particular locations in order to protect others.

    The flora and fauna within New Zealand are some of the most remarkable in the world. A large majority of the animals and plants (and fungi) are endemic, or unique, to New Zealand. Over the years, many species have been introduced to New Zealand, such as ferrets, stoats, hedgehogs and ship rats, that have put these unique animals and plants at risk. It has become vital that monitoring and control of these predators is implemented to allow our native species a greater chance of survival.

    Research to improve strategies and techniques to monitor and remove these predator species has been underway for many years now. One method used to monitor these predators is through deploying food-based lures that attract the target animals to traps or cameras. This allows for observations to be made in order to determine the density of these species in the surrounding area, as well as to increase the chances of trapping and removing these animals.

    One way to attract these predators is to use odours from more dominant predators to attract the target species to the traps or cameras. This technique is based on the observation that mammals, like stoats and rats, use scent as their primary sense to forage for food and detect dominant species (higher ranking species than themselves). Dominant species directly influence the behaviour of mesopredators (mid ranking predators) by either attracting them or repelling them away from the odour. A dominant predator’s odour may provoke the subordinate (lower ranking predator) into preforming eavesdropping behaviour. This behaviour is used by species to inspect the location where the dominant predator has roamed. If the location is good enough for the big, tough predator then maybe it is a good place for the subordinate as well.

    Researchers from Lincoln University, University of Auckland and Landcare Research chose to test ferret odour verses fresh rabbit meat (a traditional lure) for stoats, hedgehogs and ship rats. This study took place at Toronui station, a 1500 hectare sheep and beef farm located in Northern Hawkes Bay. It lasted for 64 days trial.

    From left to right; Stoat (Mustela erminea), Hedgehog (Erinaceus europaeus), Ship Rat (Rattus rattus) and Ferret (Mustela putorius furo), all mammalian predators introduced to New Zealand. Charlie Marshall, (CC BY 2.0), https://www.flickr.com/photos/100915417@N07/49407663736; Jesus Duarte, (CC BY-NC-ND 2.0), https://www.flickr.com/photos/26795194@N00/8897432606; Amanda and William Explore, (CC BY-NC 4.0), https://www.inaturalist.org/observations/120567285; Max Moreau, (CC BY 2.0), https://www.flickr.com/photos/9426349@N07/6085681724.

    The results from this trial confirmed that the ferret odour was the best for attraction, at least for stoats and hedgehogs, while rats avoided the ferret odour. Other studies have also found that rats avoid fresh odours. Stoats showed the strongest attraction to the ferret odour, with double the number of stoats being observed at the monitoring stations compared to fresh rabbit meat. These results can lead to exciting new possibilities to improve the monitoring and management of these species, especially in places where they are predicted to be rare.

    One surprising result that was found was that the population of stoats at Toronui station before the study began was estimated to be rare. After the study was completed, the stoat population was predicted to be widespread. This makes you wonder just how underestimated the population of stoats in New Zealand really is.

    Studies like this are important as New Zealand. With very limited native mammals, the native species, such as birds and insects, within New Zealand have had no need to adapt to mammalian predators. As a consequence when predator mammals were introduced into New Zealand they caused devastating damage to the endemic species.

    Ferret odour lures were found to last longer than the fresh rabbit meat lures. This means that the ferret odour lures can be left out in the field for a longer period of time and still work just as well. Rabbit meat lures become ineffective faster leading to underestimates of pest populations.

    The finding of the effectiveness of ferret odour as an attractant, especially in stoats, introduces a new tool and opportunity for pest management and conservation. It opens up many paths for future research to develop and learn more about this type of monitoring and the positive effects that it could have on our native species. More recent work has reported similar outcomes.

    Mammalian predators are a major threat to the unique biodiversity that we have in New Zealand. New discoveries, such as the use of dominant predator odour in predator removal, gives me hope that there is a future for our taonga, native species.

    The author Stacey Lewthwaite is a postgraduate student in the Master of International Nature Conservation taught at Lincoln University. This article was written as an assessment for ECOL 608 Research Methods in Ecology.

    Garvey, P. M., Glen, A. S., Clout, M. N., Wyse, S. V., Nichols, M., & Pech, R. P. (2017). Exploiting interspecific olfactory communication to monitor predators. Ecological Applications, 27(2), 389-402.