Deadly Flora; New Zealand’s Nasty Natives

Posted by Robert Vennell @RobertVennell

The wildlife of New Zealand often seems pretty tame, especially in comparison with our Aussie neighbours. In Australia, everything can kill you – crocs, spiders, snakes, jellyfish and even octopus. In contrast, New Zealand is a land of flightless birds and frisky parrots. Other than the weather, wasps and the odd feral pig, there is little to fear when tramping out in the wilderness. But while we may be lacking in ferocious beasts – we do have our fair share of deadly plants.


The toxin from five Ongaonga (Urtica ferox) spines is enough to kill a guinea pig

Native plants can pack a serious poisonous punch, and death is by no means quick or
pleasant. Take for instance Ongaonga, the New Zealand tree nettle. It’s covered in an array of poisonous syringe-like spines. When an unfortunate victim disturbs the plant, the spines are released – injecting them with a potent cocktail of toxic chemicals that attack the nervous system. In high doses, the victim loses motor coordination and convulses violently. The toxin from just five of these stinging spines is enough to kill a guinea pig and there has been one reported death in modern times1.


The seductive Tutu (Coriaria arborea) makes killer pies. Literally.

Perhaps even more deadly is the seductive Tutu. It can be seen dangling bunches of delicious purple grape-like fruit along river valleys. But while the succulent flesh of the berry is edible, accidentally eat the tiny black seed and it might be the last thing you ever do. The seed, leaves and stems all contain the powerful neurotoxin Tutin, which send the body into violent neuromuscular spasms. The plant is completely unforgiving – and has claimed the lives of a number of settlers who tried to make tutu beer and pies2. Recently, a tramper cooked and ate a tutu shoot mistaking it for supplejack. He was sent into violent convulsions which dislocated his shoulder, but thankfully survived the ordeal.


The humble Karaka (Corynocarpus laevigatus) – underestimate it at your peril.

Or how about the humble karaka berry? Inside the bright orange flesh of this classic coastal tree is a kernel packed full of the neurotoxin Karakin. Eating the kernel without proper preparation could render you permanently paralysed, as the neurotoxin causes violent convulsions which can bend bones out of place2. Human poisoning is fairly rare nowadays, but a number of dogs have been poisoned, including Mungo, Malo and Honey Bear.

Considering the deadly nature of some of our native plants, it’s surprising that they don’t have greater recognition. Thankfully however, it’s pretty easy to avoid these plants and fatalities are pretty rare. But if like me, you enjoy munching your way through the forest – it’s a healthy reminder that New Zealand wildlife can be deadly, particularly if you’re putting it in your mouth.

Robert Vennell - Hunua Ranges Berry collection

A collection of (mostly) edible plants from a recent field trip to the Hunua Ranges.

Connor, H.E. 1997. The poisonous plants in New Zealand. Wellington, Government printer.
2 Crowe A. 1981. A Field Guide to the Native Edible Plants of NZ. Penguin Books.
3 Riley M. 1994. Maori Healing and Herbal. NZ Ethnobotanical Sourcebook. Viking Sevenseas NZ Ltd.

Robert VennellRobert Vennell is an MSc student in the Centre of Biodiversity and Biosecurity, University of Auckland studying the impacts of wild pigs on native forests. He is supervised by Margaret Stanley, Mark Mitchell (Hawkes Bay Regional Council),Cheryl Krull (AUT) and Al Glen (Landcare Research). He also writes about the history, meaning and significance of New Zealand’s native tree species at

Is mist netting safe for birds?

Posted by Carolina Lara @carislaris

An amazing advantage of having collaborated in avian studies in different countries is that I have learnt a range of different techniques people use to carry out ecological research. Of particular interest to me, given the nature of my PhD project, is the capture of birds using mist nets, better known as mist netting. Mist netting is a common technique for monitoring avian populations – it can provide data on population density and demography, but it also allows researchers to collect morphometric data and blood and faecal samples, attach devices and gain information about the birds’ feeding habits.


Bird poo collected to analyse feeding habits in urban forest fragments

Mist netting is labour intensive, especially in a natural environment such as a forest.  It requires looking for the most suitable location to place the mist nets, putting the nets up and then waiting to capture some birds (usually between 7–8 hours effort). The mist net set up (number of nets, timing) will vary according to the target species, the type of habitat, and the research questions being asked.

To me the beauty of mist netting is having the chance to hold a bird (yes, even that vicious tūī ). However, a high level of expertise is required to avoid injuries to the birds. Once captured in a mist net, a myriad of external factors (e.g. time of day or human error during handling) can affect the bird’s wellbeing. Nevertheless, it is an extensively used capture technique, so how safe is it?


Often people are too scared to come close to a captured tui

An interesting study quantifying rates of bird mortality and injury for 22 banding organizations in Canada and the United States showed that the average rate of bird injury and mortality from 620,997 captures was less than 1%. The most common incidents were wing injuries, stress, and cuts, with heavier birds more prone to incident within and among species. While the study found risks to birds are low, it is highly advised that new bird handlers are properly trained in mist netting techniques so they can safely extract and process birds captured in mist nets.

Mist netting is the part I enjoy the most about my research and has given me the opportunity to work with volunteers who enjoy this as much as me. For me mist netting is not only about collecting data for my study, but is also about engaging different people with real-life conservation.


Decreasing the handling time of a captured bird is important to reduce risk of incident



Carolina Lara M. is a PhD Candidate within the Centre for Biodiversity and Biosecurity, School of Biological Sciences, University of Auckland. Her research interests focus on seed dispersal networks within fragmented landscapes. She is supervised by Margaret Stanley,Jason Tylianakis, Karine David, and Anna Santure.

Are we ready for more weeds with a changing climate?

Posted by @mc_stanley1

Here in Auckland it appears that home owners want to pretend they’re always on that tropical holiday in Queensland. Aucklanders seem to have an unhealthy obsession with palm trees.

palm house

An example of an Auckland house with a tropical paradise & an exotic palm obsession

Unhealthy you say? Well, apart from the nasty injuries as a result of phoenix palm spines, I don’t mean unhealthy for people – but some introduced palms are certainly unhealthy for our native ecosystems.

The downside of wanting to retain that tropical holiday feeling around our houses, is that several introduced palms and other subtropical/tropical species have been planted in large numbers over the last decade, and several are showing signs of being ‘weedy’. The species we are most worried about are the ones that produce fruit that birds love eating and dispersing (think phoenix palm), and that are shade tolerant. Seedlings and saplings of shade tolerant species, such as bangalow palm, can germinate and grow inside native forest fragments, and can easily outcompete our native nikau palm.


A) Juvenile bangalow palm (Archontophoenix cunninghamiana) growing in an Auckland forest fragment. B) Bangalow and nikau seedlings growing side by side in a fragment – correct identification is difficult for community weeding groups.

While this spread is happening right now, we know that these subtropical/tropical species will be more successful and invasive in an increasingly warmer New Zealand – with the advance of climate change. Just a few less frosts per year is likely to mean that these species survive the winter and become more abundant and spread further south as conditions change.

So are we ready for this?

We don’t think so.

Christine Sheppard, Bruce Burns and I have recently written a ‘forum article’ in the New Zealand Journal of Ecology, where we raise this very issue. Despite knowing this will happen, and that we’ll have a whole lot more weeds to manage in the future, there’s not a great deal of tangible action. That’s because we currently have >400 environmental weeds we are already dealing with, and the thought of trying to pre-emptively manage more is frankly overwhelming.

There are things we can do though:

  • Include climate change in our current prediction and prioritisation processes, i.e. incorporate a ‘climate change factor’ into estimates of ‘predicted land infested’, and prioritise species likely to be weedy in our regions with fewer frosts and warmer temperatures;
  • improve funding streams for weed surveillance – so we can detect and manage these species before they take off and become unmanageable;
  • robust use of citizen science weed surveillance to increase NZ’s surveillance capacity;
  • raise awareness of the danger of increased ‘weediness’ under climate change and take a pre-emptive strike by educating the public about their plant choices and prevent invasion by banning high-risk species.


The last point is probably the most important. How can we change behaviour and have a conversation with the public about their plant choices? I don’t want to rain on anyone’s ‘tropical parade’, but really New Zealand, it’s time to wake up – leave those tropical paradises in the tropics and protect NZ.


Do we want those Aussie palms?

Yeah nah! No more palmsies for you.



Sheppard CS, Burns BR, Stanley MC. 2016. Future-proofing weed management for the effects of climate change: is New Zealand underestimating the risk of increased plant invasions? New Zealand Journal of Ecology 40:



me2smallDr Margaret Stanley is a Senior Lecturer in Ecology, School of Biological Sciences, University of Auckland and is the programme director of the Masters in Biosecurity and Conservation. Her interests in terrestrial community ecology are diverse, but can be grouped into three main research strands: urban ecology; invasion ecology; and plant-animal interactions.




Dr Christine Sheppard is a former member of the Ecology Ngātahi lab group, completing her PhD on the invasiveness of newly established alien plants under different climate change scenarios. She is now a postdoctoral fellow at the University of Hohenheim in Germany.

Care for the ‘creepy-crawlies’

Posted by Keely Paler, @keely_paler

Climate change. It is something that almost everyone has heard of. There are 226,723 articles on Scopus using this key word and it is widely talked about by everyone from John Oliver to Alice Baranyovits. It is essentially the result of excess greenhouse gas emissions, which causes a range of changes including increased temperature, shrinking glaciers and altered nutrient stores. Whilst many of my friends think that these warmer temperatures will be awesome and that it’ll allow them to sunbathe more, not all species agree. It is likely that these changes will impact a wide range of environments and species.

sunbathing weevil copy

Not all species think that climate change will be awesome

Most climate-change attention tends to focus on big, charismatic species because they are easily noticeable and intrinsically interesting. For example, we would immediately notice an elephant in a room and wonder why it’s there, but we are a lot less likely to see or care about a ladybird. However, we should care about insects because they have many significant ecological roles, economic impacts, and interesting stories. And it is likely that climate change will impact these ‘creepy-crawlies’ because temperature plays a big role on their development, reproduction and survival. Unfortunately, climate change research rarely focuses on native invertebrates.

elephantWhat do you notice first? The elephant or the beetle? Does this mean that the elephant matters more?

This is where my master’s research comes in. We are trying to determine the impact of climate change on alpine beetle communities by manipulating temperature and nutrient levels around individual tussock grasses. We then used pitfall traps to collect the associated beetle communities. These traps are holes in the ground used to trap invertebrates. This allows us to see what sort of beetle species are in the surrounding area. So far, I have sorted over 12,000 beetle specimens into 137 different species and will shortly begin making comparisons between communities.The aim of this, is to determine whether these beetles communities are different if they are subjected to two components of climate change.

pitfall trap drawing          pitfall

Beetles are not the smartest creatures, and will fall into these pitfall traps, without realising that they are there. This allows us to passively sample invertebrates.

Whilst sorting through these beetles may sound like the most boring thing ever, I have started noticing all these cool creatures that I probably would’ve otherwise ignored. I guess that I have begun to like these creepy-crawlies and really think that they should be protected from Climate change.

Cool stuffSome of the cool things which I have discovered in the pitfall traps

Keely Paler is an MSc student in the Centre of Biodiversity and Biosecurity, School of Biological Sciences, University of Auckland. She is supervised by Darren Ward, Rich Leschen and Adrian Monks (Landcare Research) examining climate change and alpine insects.