The Current Status of Predators on New Zealand Offshore Islands

Posted by Zach Carter

New Zealand is committed to preserving its uniquely rich biological heritage with Predator-Free New Zealand (PFNZ). This audacious programme is focused on ridding the country of the three most biologically and economically harmful mammalian taxa by the year 2050 (Innes, Kelly, Overton, & Gillies, 2010). Pests targeted for eradication include rodents (Rattus rattus, R. norvegicus, R. exulans), mustelids (Mustela furo, M. ermine, M. nivalis) and the common brushtail possum (Trichosurus vulpecula). These mammals predate upon native biota and threaten to undermine New Zealand’s most lucrative industries, including tourism and the primary industries. There is unilateral support for PFNZ, but how close are we to actually achieving this goal on New Zealand’s offshore islands?

If we exclude large islands that are source to substantial pest populations, including Stewart Island (Rakiura) and Great Barrier Island (Aotea), and islands that cannot support mammalian life for extended periods (islands < 5 hectares, ha), 85 offshore islands (islands ≤ 50 kilometres from the mainland) currently host PFNZ mammal pests. Insofar, 87 offshore islands have been eradicated of mammals since New Zealand began systematic removals in 1980 (Figure 1). This means that over half (50.5%) of the islands with a historical pest presence have been eradicated!

Figure 1: PFNZ mammal eradications that have occurred on New Zealand offshore islands from 1980 through present.

If we investigate the total amount of island area eradicated in this dataset, we paint a slightly different picture; 84,300 ha of island area currently host mammal pests, and 24,200 ha have been eradicated. This means that only 22.3% of island area historically hosting mammals have been eradicated. Note, this dataset includes only cases of confirmed pest presence (islands with an unknown status were excluded) and excludes incursions as being considered confirmation of pest presence. Moreover, these numbers do not coincide with other eradication estimates that use different geographical boundaries or different pest species (e.g.(Towns, West, & Broome, 2013).

Admittedly, there is much work left to accomplish. This does not mean that PFNZ is impossible, though, only that it will be an uphill battle. In order to keep with the designated timeline, multiple government agencies and private groups have come together seeking creation of new (or “future”) control technologies that can address issues of ethical and technical concern. Transformative genetic control tools (including virus-vectored immunocontraception, RNA interference, and transgenic ‘Trojan’ approaches), and novel takes on current-day technology (including automated self-resetting traps, remote monitoring, and highly attractive lures) are being designed to target specific species in a manner that is cost-effective, environmentally benign, and exceeds the public conception of humaneness (Campbell et al., 2015). Such tools will be essential to the success of PFNZ. If they can be implemented in a timely manner, New Zealand will be well on its way to being the first nationwide endemic sanctuary.

Zach Carter is a PhD student at the University of Auckland in the School of Biological Sciences. He works with Dr. James Russell prioritising eradications of mammal pest species throughout New Zealand.


Campbell, K. J., Beek, J., Eason, C. T., Glen, A. S., Godwin, J., Gould, F., . . . Ponder, J. B. (2015). The next generation of rodent eradications: innovative technologies and tools to improve species specificity and increase their feasibility on islands. Biological Conservation, 185, 47-58.

Campbell, K. J., Beek, J., Eason, C. T., Glen, A. S., Godwin, J., Gould, F., . . . Ponder, J. B. (2015). The next generation of rodent eradications: innovative technologies and tools to improve species specificity and increase their feasibility on islands. Biological Conservation, 185, 47-58.

Innes, J., Kelly, D., Overton, J. M., & Gillies, C. (2010). Predation and other factors currently limiting New Zealand forest birds. New Zealand Journal of Ecology, 34(1), 86.

Towns, D. R., West, C., & Broome, K. (2013). Purposes, outcomes and challenges of eradicating invasive mammals from New Zealand islands: an historical perspective. Wildlife Research, 40(2), 94. 10.1071/wr12064

Community conservation: ‘HIMBY’ not ‘NIMBY’

Posted by Margaret Stanley @mc_stanley1

I recently participated in a community conservation forum, when a community engagement colleague coined the acronym ‘HIMBY’. I was exasperated by what I perceived as the community not being able to see the ‘big picture’ of evidence-based strategy around pest management and restoration.

 “It’s the opposite of NIMBY [Not In My BackYard]” she said. “It HAS to be In My BackYard – HIMBY”. And she’s dead right. This particular scenario is increasingly raising its head as community groups voraciously compete for conservation funding and action.

Of course we desperately need highly activated communities to be engaged in conservation and restoration. We can enhance biodiversity over a larger area with limited resources when community groups and volunteers give their time and energy for free. It’s also important to have place-based conservation – this allows a sense of ownership and community buy-in that allows sustainability of people and groups over time. Ecologists have long since recognised that ecological science alone won’t solve conservation problems, and social science and community partnership is a critical cog in the conservation wheel.

However, we also need to remind our communities about the risks of ‘HIMBY’ and community-based conservation. One of the major risks of a national emphasis on community-based conservation is that funding could be diverted away from areas that don’t have people – then we could end up in a situation where much of our conservation action is not taking place on land that is representative of different ecosystem types/biodiversity. In fact, we know that community conservation is biased towards coastal forest ecosystems, where people are concentrated.

At a local level, where funding and resources are prioritised and allocated within regions or cities, ‘HIMBY’ is alive and well. Community groups within cities/regions are understandably vying for resources. However, prioritisation of pest management must incorporate more than community activation. Firstly, it must be cost-effective and have preventative outcomes, rather than the ambulance at the bottom of the cliff. We should prioritise prevention. The Treasure Islands programme which funds pathway biosecurity to prevent pest invasion on Hauraki Gulf Islands both 1) protects assets with previous large investment in removing pests (e.g. Rangitoto-Motutapu Islands) and 2) prevents new invasions, thereby saving money in the long term. We know how cost-effective it is in medicine to vaccinate rather than belatedly treat the disease.

Given the impacts of Aotearoa-New Zealand’s invasion debt, we have to continue to ‘treat the disease’ and reduce pests and restore habitat. But the ‘where’ should be decided strategically. Yes, the degree to which a community is activated is a key factor in prioritisation along with other cultural and societal factors, but ecological factors (beyond our backyards), such as level of pest infestation, the value of the conservation assets within sites, and habitat connectivity, should be key factors in deciding where conservation actions should take place to achieve the best outcomes for biodiversity across the city or region.

Invasion Curve Animation  – explains the principles of prioritization for pest management based on cost-effectiveness (You Tube: ‘ Invasion Curve Animation Biosecurity Council of WA’).

Although we’re primed as humans to be highly attached to ‘our backyard’ and want the best outcomes for it, we need to see the wood for the trees. This is why larger-scale conservation visions, such as the North-West Wildlink and Cape to City are becoming increasingly important. If we can all buy into the larger landscape scale conservation vision, then we will be willing to see that the priorities for action/$$ spent might not be in our backyard, but over the fence, in someone else’s backyard. We’ll also understand that by taking action in the neighbour’s backyard, we will benefit from the biodiversity spilling over into our backyard.

Time to look up from our backyards and take on the larger vision.

Dedicated to the champion work of conservation staff within agencies engaging with communities, and also to those champion activators within our communities, rallying people to conservation action!

Margaret Stanley

Dr Margaret Stanley is an Associate Professor in Ecology, School of Biological Sciences, University of Auckland. Most of her research is applied ecology, working to improve outcomes for biodiversity.

Insect population persistence: the do-or-die of dispersal

Posted by Hester Williams @HesterW123

Dispersal is an integral part of population dynamics. Through simply moving from one habitat patch to another, the dispersal of an individual has consequences not only for its own fitness, but also for population persistence and distribution.

Understanding the causes and consequences of dispersal is vital for population management and predicting population response to changes in the environment. This is particularly important in conservation and re-introduction efforts, biological control and management of alien species. Furthermore, the factors that determine the extent to which dispersers are selective and capable when searching for a new habitat is of interest.

A newly arrived population of a potentially invasive species is usually small, and dispersal could play an important role in its establishment success. Species with a high dispersal rate could end up spread out too thinly, resulting in the inability to find suitable mates, the loss of predator dilution or to defend against predators. These and/or other component Allee effects could scale up to a demographic Allee effect and ultimately lead to the demise of the population.

Reasons for dispersal

The reasons for dispersal are multiple and could include factors such as finding suitable host patches, finding potential mates, avoiding inbreeding with kin, avoiding intra- and interspecific competition, and escaping low or declining host patch quality.

Cues used during dispersal

The bee Chelostoma rapunculi makes use of a combination of visual and olfactory cues to find its host plant

When searching for a new habitat patch, insect dispersers make use of several cues, including visual (shape, size, colour) and/or olfactory cues (communication chemicals such as host-plant volatiles and pheromones). For example, the bee Chelostoma rapunculi makes use of a combination of visual and olfactory cues to find its host plant. Similarly, the Asian Longhorned Beetle, Anoplophora glabripennis uses both olfactory and visual cues to locate its host plant Acer negundo.

For certain insect species the chemical cues from colonised host plants are important in host location; in this case both cues released by conspecifics already colonizing the plant (pheromones) and plant cues induced by herbivore feeding (feeding-induced plant volatiles), or by oviposition, can influence the apparency of the host patch. This gives rise to a clumped distribution or aggregation of the insect species on selected host patches.

Using chemical cues from colonized plants can be both beneficial and detrimental. Particularly, it signals the availability and quality of food and the presence of conspecifics, thereby negating the Allee effect through dilution of predation risk, overcoming host defences and ensuring potential mates. Ultimately it reduces search costs, and other costs related to exercising vigilance during foraging and mate-finding. For example, the flea beetle, Phyllotreta cruciferae, makes use of a combination of male-produced pheromone and feeding-induced host volatiles to form aggregations under field conditions.

On the negative side, the volatiles from an herbivore-infested plant represent a food source with competitors and elevated risk of influx of predators and parasitoids. For example, feeding-induced volatile emissions from Nicotiana attenuata plants increased predation by a generalist predator, Geocoris pallens, on the eggs of the flea beetle Epitrix hirtipennis.

My study

My interest in the topic of dispersal is its role in the initial establishment and population growth of small, recently arrived populations of alien species – especially during eradication efforts when small populations are subjected to management actions such as host removal. During this process habitat is broken up into fragmented host patches, often with reduced numbers of individuals scattered over several patches surrounded by unsuitable matrix. Should these individuals roll the dice and aggregate?, and thereby form a population large enough to overcome Allee effects. If they remain scattered (no dispersion or inefficient dispersion), will they eventually die out?

Neolema ogloblini adult on stem of Tradescantia fluminensis.
Photo: Murray Dawson.

My studies use the leafbeetle Neolema ogloblini, a biocontrol agent for Tradescantia fluminensis in New Zealand, as proxy for an invasive insect pest species. By studying the dispersal choices of recently released adults of N. ogloblini, I was able to determine that the beetle species utilizes cues from colonized host patches. The beetles responded to the presence of actively-feeding adults, but not to non-feeding adults, suggesting their response is motivated by feeding-induced volatiles and/or pheromones that are only released while feeding.

Experiments to determine how efficient the beetles are at finding patches of their host plant as influenced by the degree of isolation of a potential host patch and the matrix surrounding it, is to be completed this summer.

Results of my studies will ultimately give guidance on what eradication approaches are promising for particular invasive species.

Hester Williams is a PhD candidate in the School of Biological Sciences, University of Auckland and is stationed with the Landcare Research Biocontrol team in Lincoln, Canterbury. She is interested in invasion processes of both insect and plant species. Hester is supervised by Darren Ward (Landcare Research/University of Auckland) and Eckehard Brockerhoff (Scion), with Sandy Liebhold (USDA) as advisor. Her studies are supported by a joint Ministry for Primary Industries – University of Auckland scholarship. The project is an integral part of an MBIE program “A Toolkit for the Urban Battlefield” led by Scion.

Celebrate fruit fly detections in New Zealand

Posted by Prof Jacqueline Beggs @JacquelineBeggs

About to bite into that luscious, juicy taste of summer, a tree-ripened nectarine? Be thankful you do not live anywhere with fruit fly.  This group of insects are infamous for the damage they do to a wide range of fruit and vegetables.

Apricot (left) and pear (right) are two of the many fruits affected by fruit fly. Images used by permission Plant Health Australia

As well as summerfruit, they attack citrus, apples, pears, berries, grapes, olives, persimmons, tomatoes, capsicum, eggplant, and avocado. We are not talking a bit of cosmetic damage to the skin – fruit can end up as a soft, mushy, inedible mess. Fruit fly females lay eggs into fruit and the developing maggots munch away, causing the fruit to rot and drop to the ground.

The extent of damage can be devastating. The island of Nauru ended up home to four species of pest fruit fly.  By 1998, about 95% of mango were infested and island-grown fresh fruit and vegetables were so scarce locals had to rely on more expensive imported produce. Fortunately, an intensive lure and poison programme eradicated three of the four species and mango and breadfruit were back on the menu.

Australia is not so lucky. They have two highly damaging fruit fly species, the Queensland fruit fly and Mediterranean fruit fly. Commercial growers spend hundreds of millions of dollars on various control measures and quarantine measures are in place to try to stop the spread into uninfested areas. With varying degrees of success.

A single Queensland fruit fly (Bactrocera tryoni) was recently detected in Devonport, New Zealand. A full scale response has been triggered as it is regarded as a serious pest [Image: James Niland, Wikimedia commons ].

It is no surprise then that detection of two different species of fruit fly in New Zealand in a week makes headline news and our dollar falls. Finding a second Queensland fruit fly near to the first is concerning. We certainly do not want them to establish. However, I think we should also celebrate. The detections are really New Zealand’s biosecurity system operating at its best. We have in place a world class fruit fly detection system; a nationwide surveillance network of 7737 traps baited with fruit fly specific lures that are checked seasonally.

Including the three latest finds, this network has detected 13 incursions of economically important fruit flies since 1989.  More importantly, early detection and effective control means fruit flies have not established in New Zealand. With such high stakes, it is critical that we keep going with research to improve surveillance, eradication and control tools. Recent PhD work at University of Auckland by Dr Lloyd Stringer is a good example; he developed a population model that helps to identify the most successful management and eradication options for Queensland fruit fly.

We cannot afford to take our foot off the pedal. Fruit fly will keep pushing at our border since there are around 80 pest species found in many countries we trade with and travel to. Furthermore, some regions have given up trying to achieve area wide fruit fly control, leading to higher density of these pests. That makes it easier for an individual fly to slip past all the measures we have in place to keep them out. So hats off to all the folk involved in keeping fruit fly at bay. That includes you – letting biosecurity officers onto your property to check for infestation, making sure you do not move fruit or veges from “controlled areas”, and encouraging everyone to never bring undeclared produce into New Zealand.

Prof Jacqueline Beggs is Director of the Centre for Biodiversity and Biosecurity, a member of the Biosecurity Ministerial Advisory Committee and co-supervised Dr Lloyd Stringer for his PhD research. And nectarines are probably her favourite fruit!

Hello darkness, my old friend

Posted by Ellery McNaughton @EJ_McNaughton

Who’s afraid of the dark? Society in general it would seem. Some people have good reason to be, living in places where humans are not top of the food chain, and darkness provides cover for those that are. Yet even in places where predation is not a risk to contend with, darkness gets a bad rap. The Dark Side, the Dark Lord with his Dark Mark, dark magic, somehow we have conflated darkness with evil. Perhaps this is because in the dichotomy of light and dark, light outshines darkness in the PR department. Light is the stuff angels wear to look suitably holy. Light signifies safe places for lion kings to rule their lion kingdoms. Light is the symbol of enlightenment and civilisation, an indicator of human innovation, technology and progress. And in the immutable logic of opposing pairs, if light = good, then darkness must therefore = bad. It’s algebra, or something.

Light side dark side

Choose light or choose dark. Choose the hero or the villain. Somehow they’re always the same choice

However, darkness really is our friend, preserving our sleep patterns and physiological processes, keeping our biological clock running in an orderly manner. It’s an unappreciated and often abusive friendship on our part. Natural darkness is being eroded away as we increasingly choose to hang out with the cool new kid, light. Natural limiters of daily activity are for lesser species, and if we want to work late into the night, nothing can stop us (even if the numerous health problems should). Some people love light so much that when their streetlights are changed to have less light spill, they buy outdoor lights to make up for the lack of illumination. That’s not just enabling a later bedtime; it is actively avoiding the presence of darkness. Why are we afraid of the dark?


Dumbledore promoting light pollution

While urban dwellers generally don’t have to deal with predation, in the dark we often feel at risk from other humans. Walking home at night becomes an exercise of fearful imagination, where every shadowy bush, alley or doorway becomes a hiding place for others up to no good. Light banishes the shadows and leaves no place for imagination to run riot; security lights are so named for a reason – they make us feel secure. This is in spite of the fact that light doesn’t appear to reliably banish the presence of the criminal element. Of course, even if light doesn’t actually make us safe, it is important for people to feel safe in their cities. And until we as a society stop viewing darkness as a villain to be conquered, light is a necessary evil.


Ellery McNaughton is a PhD student in the Centre of Biodiversity and Biosecurity, School of

Ellery (2)


Biological Sciences, University of Auckland. Her project investigates the effects of a city-wide changeover in streetlight technology on urban bird behaviour and ecosystem function. She is supervised by Margaret StanleyJacqueline BeggsKevin Gaston (University of Exeter, UK) and Darryl Jones (Griffith University, Australia).

Missed opportunities in the SPCA controversy

Posted by: Jessica Devitt @Colette_Keeha

Last month I was closely following the news and debates that were sparked by the RSCPA of New Zealand’s (herein SPCA) official stance on the use of 1080 in pest control.

Figure 1. Ban 1080 protesters speak to Newshub (Newshub, 2018).

The SPCA wants the toxin 1080 (aka sodium monofluoroacetate) banned because it considers the toxin an inhumane way of reducing pest animal populations.  The SPCA further notes that it does not regard one type of animal as more deserving of life than another, arguing there is no justification to control pest animals in the first place, and that ways to allow conflicting species to ‘co-exist’ should be encouraged.

I am pro the use of 1080 based on the positive outcomes it has for native species. I am in agreement with the Parliamentary Commissioner for the Environment that 1080 is the most effective invasive species management tool that we have at this point in time.


Figure 2. A large male L. barbicornis guards a female drilling an egg-laying hole (Painting, 2013).

I was a financial supporter of the SPCA for several years with monthly, albeit small, contributions. I decided to withdraw my support for them post their 1080 statement, and instead I promptly spent my money on joining Forest and Bird, whom I had never financially supported but always wanted to.

I did actually think quite a bit about this before doing it – I am not a big fan of ‘cancel culture’, so I did not want to boycott the SPCA over one disagreement, and part of me felt like I was doing that. However, realistically I had to look at the bigger picture and I realised that their statement and some of the attitudes expressed within it do not align with me.


In fact, the ongoing debate made me realise that although the thought of native species loss filled me with genuine sadness, it did not always spark the same kind of outrage that I got from seeing domestic animals harmed or neglected by humans. I never really looked at the loss of native species as an animal welfare issue, when actually it is. I academically understood the issue of native species loss, but it is not something that I am reminded about regularly with visually disturbing pictures; like what is often seen with domestic animal abuse.


Figure 3. Possum and rat both preying on a thrush nest (Nga Manu Images, n.d.)

My issue with the SPCA’s statement, was in retrospect, more to do with how they went about stating their position rather than me expecting them to be pro 1080 or agree with its use.  Their statement was very one-sided, completely failing to grasp the complexities of the situation. It briefly notes reproductive control of pest species as an alternative option. However, this is not a straight forward fix. Reproductive control is not an option for most of New Zealand’s mammalian pests as there is no way currently this can be applied at a scale that would lead to significant reduction in pest numbers. Furthermore, applying reproductive control has its own set of problems – adding reproductive hormones to the environment has many downstream impacts on non-target wildlife, and surgically sterilising then releasing animals still leaves them hunting and killing native wildlife for the rest of their lifetime.


Figure 4. Gene editing (Luecke & Steadman, n.d.).

The SPCA firmly stands on the side of ‘ban 1080’ by supplying links to ways in which you can support a ban, but fails to give other options, such as supporting your local environmental group or donating funds to Predator Free NZ or Forest and Bird for their continued research on predator control. Both of these organisations are interested in finding alternatives to 1080.


Figure 5. Predator Free NZ logo (Hill, 2018).

The press release reads more as an individual’s viewpoint and something that would have been more fitting in a blog (such as this) than a press statement by a large well-established organisation.  The release appears out-of-place in comparison to the other press releases on the website. Looking over the past year of press releases I could not see any big statements taking a side on other topical animal welfare issues such as the horrors of the dairy industry, horse racing, rodeo, releasing pets into the wild, trapping, and other poisons besides 1080.

I am not surprised that the SPCA does not endorse the use of toxins for pest control; I think this would be expected from any animal welfare group. I also think it’s pretty clear from the subsequent debate that everybody would like a more humane method of pest control. I think that the SPCA really missed an opportunity here to offer up other ways in which people can support pest free New Zealand without necessarily jumping straight to ‘ban 1080’.


Figure 6. Community conservation groups. (Department of Conservation, n.d.)


Addendum: Forest and Bird met with the SPCA on January 22nd to discuss their position on 1080. The SPCA clarified that their position is to encourage more research and development into alternative non-toxic pest control methods.  Forest and Bird also stated that the SPCA will amend it’s statement to reflect this (@Forest_and_Bird, 23rd January 2019,

Here is a list of some of the organisations that are currently working to find alternative means of pest control:

Biological Heritage National Science Challenge

Predator Free New Zealand

Genomics Aotearoa

Forest and Bird

The Royal Society of New Zealand

Manaaki Whenua – Landcare Research

Department of Conservation

Here is are a couple of links that connect people to local conservation efforts:

Department of Conservation

Conservation Volunteers New Zealand



Jessica Devitt is a PhD student at the Centre for Biodiversity & Biosecurity, School of Biological Sciences, University of Auckland and Plant and Food Research. She is researching the respiratory responses of the golden-haired bark beetle to advance fumigation techniques. She is supervised by Jacqueline Beggs from the University of Auckland, Adriana Najar-Rodriguez and Matthew Hall from Plant and Food Research.



Department of Conservation. (n.d.). Community conservation groups. Retrieved

Hill, C. (2018). Predator Free NZ logo. Retrieved from

Luecke, J. & Steadman. (n.d.). Gene editing. University of Texas at Austin. Retrieved from

Newshub. (2018) Ban 1080 protesters speak to Newshub.  Retrieved from

Nga Manu Images. (n.d.) Possum and rat both preying on a thrush nest. Retrieved from

Painting, C.J. (2013). A large male L. barbicornis guards a female drilling an egg-laying hole, demonstrating the extreme sexual dimorphism in this species. Retrieved from

Te Ara – the Encyclopedia of New Zealand. (2007). Rat attacking bird’s nest. Retrieved from


New Zealand Ecological Society 2018: Great Talks and the Great Outdoors

Posted by Simon Connolly

Wellington is bloody windy. This is perhaps not the most original observation, but it certainly seems to be a correct one, particularly when your trip coincides with a severe weather warning. However, it was not the prospect of gale force winds that had me travelling south at the end of November. Ecologists from the length and breadth of the country, and beyond, were gathering for the New Zealand Ecological Society Conference, hosted at Victoria University.


The view from my accommodation (Yes, I did pick the worst day for dramatic effect)

The talks kicked off on Sunday at the conference’s student day, which was followed by three days of talks at the main conference. It would be folly to try and list all the amazing and interesting talks that were given (especially as there were over 100), but here are just a few of the highlights: the use of drones in sampling New Zealand’s epiphyte diversity; the history of the extinction of a native fish that smelled of cucumber; tadpoles that interact with the microbiome to regenerate their lost tails; mysterious fungivorous beetles; tracking New Zealand’s biodiversity with place names; the role of New Zealand’s flightless birds in seed dispersal; a myriad of talks and posters about orchids and their sexually deceived pollinators; why the straw breaking the camel’s back is more than an idiom in ecology; the drivers of social wasp abundance on New Zealand’s offshore islands; and the question of whether Kauri are thirsty at night (long time readers will note that the last three topics have been discussed on this very blog).

In amongst all this were my talks on my Master’s research (the subject of which has also been discussed on this blog). Like I said, I have not been active in the research space for very long and consequently this was my first time speaking at a major conference. The concept was a little overwhelming at first, but I soon warmed to the idea. I was most taken aback by the positive and informed response I received. Intelligent questions are one thing, but I was incredibly grateful to those who suggested improvements to my methods or offered advice from their own research and experiences.

However, a man cannot live on talks alone. Also included in my time at Wellington were two trips into the field. The first was a highly atmospheric night trip to Zealandia, an enclosed pest-free reserve near the heart of Wellington. Whilst this was blighted by the same foul weather as before, I could spend almost an entire post talking about this trip alone. Suffice to say that seeing creatures like Tuatara and Weta thriving in their natural habitat gives me some hope that all is not in vain. The second trip was to Manaaki Whenua Landcare Research’s Field Station, or at least to the far side of the swelled Orongorongo river from the field station. This trip taught me that a “short 1-hour hike” does not reckon with botanists’ ability to stop and discuss every plant.


A tuatara, inspecting the tourists from his burrow – Photo Credit: Mark Herse

All in all, my trip to Wellington was an enjoyable one, and I hope to revisit the NZES Conference in the future. Now enjoy a couple more wildlife photos.


Weta and a ‘gherkin’ slug (obligatory entomological photo) – Photo Credit: Kaavya Benjamin


A cryptic Stick Insect, found near the banks of the Orongorongo river (obligatory entomological photo 2)

jgs head and shoulders Simon is a Masters Student at the School of Biological Sciences, University of Auckland. His research is focused on threatened insects and he is supervised by Darren Ward.

Nocturnal water loss and why it matters for kauri

Posted by Tynan Burkhardt @TynanBurkhardt

Nocturnal transpiration is often ignored when studying the water relations of plants, with the assumption that stomata (small pores on the bottom of leaves) close at night, leading to negligible water loss. Although transpiration is far lesser at night than during the day, it can contribute a considerable component of daily water loss. For kauri, I have found nocturnal water loss to make up around 15 % of yearly canopy transpiration. However, for other species, nocturnal transpiration can contribute up to 30 % of daily water loss!

For many plants, night-time is a period of replenishment, where the stem water storage is refilled, after being depleted during the day. However, the importance of night time in the refilling process differs between species. In South American rain forests, where water is readily available year-round, water storage is small and very little refilling occurs at night, with most occurring in the evening. In comparison, kauri have extensive water stores, which are held within their iconic large stems and branches. Refilling of these stems and branches extends almost all the way to sunrise (Figure 1), demonstrating the importance of the nocturnal replenishment period for kauri.


Figure 1 – Daily pattern of withdrawal and refilling for kauri water storage, showing diurnal withdrawal followed by evening and night-time refilling.

Kauri rely heavily on night-time refilling in their water use strategy, with water storage buffering trees from the high evaporative demand and temperatures of summer. Night-time water loss limits a plant’s ability to refill water stores and increases in drought summers. For example, most nights of the 2012/13 drought summer had a considerable amount of transpiration, compared to last summer (2017/18), where most nights had very little transpiration (Figure 2). Worryingly, drought is expected to increase in frequency and severity for many regions where kauri is present.


Figure 2 – Frequency of nights at different levels of nocturnal transpiration (En) for kauri canopies in a ‘normal’ summer (2017/18) and a drought summer (2012/13).

But what does this mean for kauri if drought does become a common summer condition? Clearly, they will be less able to refill their water stores, perhaps leading to a water deficit as the drought progresses. However, water storage is not the only defense kauri have against drying soils. They have also been observed to drop leaves in drier summers and close their stomata when under even mild water stress. Therefore, the reduced ability to refill water storage does not necessarily mean there will be large scale kauri die offs when drought does occur, but it is one of the pathways in which kauri stands may become more water stressed.

IMG_7437Tynan is a Masters student at the University of Auckland’s Ecology Ngatahi lab group. He is studying Nocturnal Transpiration in kauri trees and is supervised by Cate Macinnis-Ng.

No “global” trend: utilising taxonomic collections for assessing the global pollination crisis

Posted by Darren Ward @nzhymenoptera

There is increasing concern about the decline of pollinators worldwide. However, despite reports that pollinator declines are widespread, data are scarce and often geographically and taxonomically biased. These biases limit conclusions about any potential pollinator crisis.

Natural history museums have the potential to transform the field of global change biology. However, museum specimens are underused and could be better utilised to reveal patterns that are not observable from other data sources. Specimens historically collected and preserved in museums provide information on where, and when, species were collected, but also contain other ecological information such as species interactions and morphological traits.

In a recent paper we provide a global synthesis of how researchers have used historical data to identify long-term changes in pollination services. We show that scientific information on the status and trends of most pollinators is poor, if not absent. For example, although a wide variety of countries have recent records of pollinators, they lack historical data. Thus, greater emphasis should be placed on the digitisation of specimens already held in natural history museums.

Furthermore, changes in pollinator communities are context specific, and ‘global trends’ need to be assessed with caution, especially when most of the globe is not assessed!

In Spain, a hot-spot for bee diversity, data analyses showed there were a reduced number of bee species, however, this trend was highly site-specific. Declines in species were clustered around certain types of bees, such as the ground-nesting bees (especially Andrenidae), suggesting a pattern of winners and losers, where some groups of bees are more sensitive to disturbance than other groups.

In New Zealand there are relatively few native bee species, however, they are well studied, and therefore museum records can be used to identify trends in pollinator communities. In contrast to Spain, we found that 11 out of 27 bee species increased in relative occurrence over time, 13 species were stable, and only three bee species declined in relative occurrence.

A greater number of long-term datasets from different countries are needed in order to provide a robust and truly global assessment of trends in pollinator communities. Natural history museums play a central role in assessing the extent of the global pollination crisis, because they are the source which can serve as a baseline.


Bartomeus I, Stavert JR, Ward D, Aguado, O. 2019. Historic collections as a tool for assessing the global pollination crisis. Philosophical Transactions of the Royal Society B. 374, issue 1763.

From a themed issue, ‘Biological collections for understanding biodiversity in the Anthropocene’.


New Zealand bee collection records were gathered from multiple sources, including university, research institute, museum and private collections. Collection records from the New Zealand Arthropod Collection (NZAC) and are freely available online (

Darren Ward is an entomologist, Head Curator at the New Zealand Arthropod Collection at Landcare Research, and a senior lecturer at the School of Biological Sciences, University of Auckland.

What drives social wasp abundances on NZ’s offshore islands?

Watch my first stop motion video on the drivers of social wasp abundances on New Zealand’s offshore islands below:


Julia Schmack is a PhD student at the Centre for Biodiversity & Biosecurity, School of Biological Scinyences, University of Auckland. She is researching the ecology and control of social wasps, supervised by Jacqueline Beggs, Darren Ward and Mandy Barron (Landcare Research). Her PhD is funded by the Biological Heritage National Science Challenge. @julia_schmack