Marvel takes a risk with Ant-Man whilst I assess the risk of ants

Posted by Anna Probert @AFProbert

Ant-Man. The official superhero of 2015 and my PhD

Ant-Man. The official superhero of 2015 and my PhD

I have a feeling that my beloved study group are going to be gaining quite a bit of interest this year. I would love to say that it is a result of some ground-breaking research I have conducted, but alas. The true reason why I think 2015 is The Year of the Ant, is the impending release (that’s 16th July) of Marvel Studio’s Ant-Man. For those of you that are perhaps not on my level of Marvel fandom, Ant-Man is based on the comic of the same name, where the protagonist has the ability to shrink down to the size of an insect and has superhuman strength and agility. Although in my spare time I’m still trying to discover Pym Particles, my full time role involves being a PhD student here at the UoA and looking at assessing invasive species risk to native ecosystems, using ants as a model.

Unfortunately for our native environment, when it comes to exotic species arriving and establishing in New Zealand, we often let them slide by if they don’t have a perceived potential social or economic impact. As a result, we end up with exotic plant and animal species that become naturalised in the environment. How do they affect the environments in which they naturalise? Well in most circumstances, we don’t really know.

Out in the Hunua baiting for ants. Photo credit Luke McPake

Out in the Hunua baiting for ants. Photo credit Luke McPake

Here in New Zealand we have 29 established exotic ant species (compared to only 11 native species) and very little understanding of how they are influencing the environments in which they live. The Argentine Ant is the species most people would have heard of, as it is a well-known invader worldwide, causing various negative impacts on the environments in which it invades. But what of the other 28 established exotic species we have in New Zealand? What are they doing?

I don’t have the answers… yet, but for my PhD I’m specifically going to be looking at the ways exotic ants influence the invertebrate community structure within different ecosystems, as well as investigating their role in altering ecosystem function. This will involve conducting different manipulative field trials over the upcoming spring/summer seasons – and I’m always on the lookout for field assistants, so let me know if you want to spend a day in nature out with me and the ants.

P.S. Marvel Studios, I am indeed open to sponsorship.

AnnaAnna Probert is a PhD student in the Centre for Biodiversity & Biosecurity, School of Biological Sciences, University of Auckland. She is using ants as a model to assess the risk posed by exotic invertebrates to native ecosystems. She is supervised by Margaret Stanley, Jacqueline Beggs, and Darren Ward.

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What we talk about when we talk about ecological networks

Posted by Carolina Lara @carislaris

I was recently asked by an engineer friend of mine what my PhD project was about. In my (failed) attempt to put it into simple words, I ended up giving him a large discourse on the topic. A couple of days passed and he got back to me to say “… I always thought biological systems were simpler”. I am new to this world of ecological networks, but simplicity is not a word that can be used to describe them. More specifically for animal-plant mutualistic networks, a set of animals interacts mutualistically with a set of plants that are connected to another set of animals that interact with another set of plants. Animals disperse a plant´s genes and get food as a reward, as in the case of pollination and seed dispersal ecosystem services.

Kereru (Hemiphaga novaeseelandiae), New Zealand’s native pigeon, feeding on Nikau Palm (Rhopalostylis sapida) fruit

Kereru (Hemiphaga novaeseelandiae), New Zealand’s native pigeon, feeding on Nikau Palm (Rhopalostylis sapida) fruit

The dynamics of these networks and how they are built have profound implications on the coexistence of species and moreover, they can give us insights about how resilient they are to human disturbances, such as habitat fragmentation. It has now been recognised that conservation efforts should not only be directed to species alone, but should also be extended to the interactions and networks they form. Loss of interactions would translate into loss of ecological functions and this could happen even before actual species extinctions, a concept known as extinction debt of ecological interactions. Daniel Janzen, a pioneer scientist in tropical ecology, stated more than 40 years ago that “what escapes the eye, however, is a much more insidious kind of extinction: the extinction of ecological interactions”. So, we really are talking about complexity when we talk about networks. And I’m glad I changed my friend´s perception of just how complex biological systems are.

Carolina2Carolina 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.

SCIENCE NEEDS YOU!!

Posted by Alice Baranyovits @ABaranyovits

New Zealand's native pigeon, the kererū, are important seed dispersers as they swallow fruits whole.

New Zealand’s native pigeon, the kererū, are important seed dispersers as they swallow fruits whole.

Having spent a fair amount of time wandering around Auckland city with a large blue antenna, I have been stopped and asked what I am doing quite a bit. Whilst it was very tempting to tell people I was looking for aliens or just trying to get a good signal for my phone, I did eventually explain to them that I was radio tracking kererū (NZ pigeon; Hemiphaga novaeseelandiae).

Alice radio tracking kererū in urban Auckland.

Alice radio tracking kererū in urban Auckland.

On the whole, people seemed pretty interested and would often tell me about the kererū they see around the city.
This got me thinking, perhaps there was a way I could get people to record this information so I could get more of an understanding of where kererū were in the city and where they weren’t. So I created a website, imaginatively entitled ‘The Auckland Kererū Project’ as a platform where members of the public can record their sightings as well as information on the plants in their gardens.

The use of volunteers in research, also known as citizen science, has long been a tool of ornithologists and ecologists – the Audubon Christmas bird count in the US is one of the longest running having started in 1900. More recently the number of citizen science projects has been increasing, helped in part by the internet and the advancement of mobile technology, which has led to much easier data collection.

One of the main benefits of citizen science is that very large data sets can be collected often over a large geographical area and time scale, much larger than what could be collected by a single researcher. Data can also be collected from private land, removing the access issues researchers often face, especially in urban areas. Participants in citizen science can also benefit through increased knowledge and appreciation of the local biota and issues in their local community and through gaining an insight into the scientific process.

Alice is studying how kererū move around fragmented landscapes and more specifically how they utilise the urban environment.

Alice is studying how kererū move around fragmented landscapes and more specifically how they utilise the urban environment.

There are some drawbacks, however, that must be taken into account during data analysis. Participants often have variable skill levels which can lead to issues with data quality. Variations in sampling effort both in time and space can also be a concern. Despite these issues, citizen science is a great tool and is likely to become even more prevalent in the future.

Want to get involved? There are many citizen sciences projects in New Zealand – one of the largest is NatureWatch NZ, which listed many different projects you can get involved with. Or how about Landcare Research’s annual garden bird survey? But of course don’t forget about the Auckland Kererū Project!

Alice Baranyovits is a PhD student at the Centre of Biodiversity and Biosecurity, School of Biological Sciences, University of Auckland. She is researching the movements of kererū in urban areas and the implications on seed dispersal of native and introduced plants. She is supervised by Mick Clout, Jacqueline Beggs & George Perry.

When natives go wild: New Zealand… a global supplier of invasive species

Stringer UoA photo

Posted by Lloyd Stringer

After reading Mick Clout’s post on New Zealand’s potential as an Ark for non-native species; a source of genetically diverse species, that could be used to repopulate the historically native ranges from whence they came, I got a-thinking… Is New Zealand a source of invasive species?

In my day job I work on ways to prevent adventive species establishment in New Zealand. I was heartened to discover that Aotearoa has been exporting more than vibrant young kiwis on overseas working holidays.

As a kid I dreamed of a never ending Christmas. That has potential to come into fruition with the spread of New Zealand’s Christmas tree, the pohutukawa, Metrosideros excelsa into European countries. Meanwhile, in South Africa, pohutukawa threaten the ecologically unique Fynbos, already under threat from other invasive species, via prolific seed production leading to dense seedling stands.

A Pohutukawa in full bloom. This species typically flowers from Dec-Jan. Credit: by Ed323 at en.wikipedia (Transferred from en.wikipedia) [Public domain], from Wikimedia Common.

A Pohutukawa in full bloom. This species typically flowers from Dec-Jan. Credit: by Ed323 at en.wikipedia (Transferred from en.wikipedia) [Public domain], from Wikimedia Common.

Another successful export has been the Karaka, Corynocarpus laevigatus. This New Zealand treasure provides a risky food requiring days of preparation to detoxify the seeds prior to eating. Karaka were used in reforestation efforts in Hawaii early in 20th century where it now forms dense stands potentially shading out local, rare endemic plant species.

Possibly some of the less iconic New Zealand species making their way around the globe are the mudsnail Potamopyrgus antipodarum and flatworm Arthurdendyus triangulatus. New Zealand’s mudsnail can reach densities of up to 300,000 individuals per square metre in some rivers, modifying ecosystem processes. Whereas on land, the flatworm, predates on earthworms which could lead to secondary effects such as a reduction in soil quality and a reduction of a food source for native birds.

Perhaps what we are seeing are the New Zealand-sourced winners that could have a chance at surviving in a possible future world that is less species–rich, instead dominated by a few widespread species.

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Lloyd Stringer is an invasive species entomologist at Plant & Food Research and doctoral student in the School of Biological Sciences, University of Auckland, investigating the interactions between eradication tools and Allee thresholds.

 He is supervised by Max Suckling, Jacqueline Beggs and John Kean. Here Lloyd is planning a red imported fire ant field experiment.

An ‘invasive ark’ for genetic diversity?

Posted by Mick Clout

Mick with binocularsA recent paper reveals that introduced stoats (Mustela erminea) in New Zealand have greater genetic diversity than in their native Britain, from where they were introduced in the late 1800s. The results are unusual because introducing a species to a new area is usually associated with a loss of genetic diversity, due to the small numbers released.

The current situation of stoats in Britain and New Zealand is the result of a series of ill-fated attempts at biological control of pests.

Hundreds of British stoats were introduced to New Zealand during the latter part of the 19th century (along with weasels and domestic ferrets) in a failed attempt to control rabbit numbers. Rabbits had previously been introduced to New Zealand for food and sport, but had become agricultural pests. The stoats introduced to New Zealand were ineffective at controlling rabbits, but they spread throughout much of the country and are implicated in the decline of many native birds, including kiwi and kakapo. The swimming ability of stoats has resulted in their colonization of several offshore islands, where they flourish, especially in the presence of introduced mice. Many conservation programmes now include the control or local eradication of stoats, to allow recovery of threatened endemic birds. However stoat incursions continue on some islands from which they have been eradicated. There are now plans for the complete eradication from New Zealand of these and other mammalian predators in the long term.

'Stoats have greater genetic diversity in New Zealand than in Britain, but this should not compromise attempts to control this invasive predator in NZ. Photo by Patrick Garvey.

Stoats have greater genetic diversity in New Zealand than in Britain, but this should not compromise attempts to control this invasive predator in New Zealand. Photo by Patrick Garvey.

Several decades after stoats were introduced to New Zealand, the native stoat population in Britain suffered a drastic decline in abundance when rabbits, their main prey there, were decimated by myxomatosis, which was introduced to Britain in the 1950s as a control measure for rabbits.

When the native stoat population in Britain collapsed in the wake of the introduction of myxomatosis, introduced stoats in New Zealand effectively conserved a reservoir of genetic diversity from the original British population.

Paradoxically, the misguided introduction of stoats to New Zealand has created an ‘invasive ark’ for genetic diversity of this species. However, this should not compromise efforts to control or eradicate stoats in New Zealand. Perhaps the British would like them back?

Professor Mick Clout is a vertebrate ecologist at the School of Biological Sciences, University of Auckland. Mick works on the conservation biology of threatened species, such as New Zealand’s native pigeon the kererū, as well as the ecology of invasive mammals, such as possums, hedgehogs, cats, mustelids and rodents. From 1993-2009 he chaired the IUCN Invasive Species Specialist Group (ISSG), a global group of scientific experts on invasive species.

What’s the point of urban ecology?

Posted by Margaret Stanley @mc_stanley1Margaret

What’s the point of urban ecology? This is a question I get asked a lot. Many ecologists believe ‘real ecological research’ occurs outside of city boundaries, preferably the further the better from a city. While the focus of ecologists and conservationists is often on biodiversity outcomes within protected areas or in rural areas, the perceptions and values of city-dwellers disproportionately (in terms of numbers of votes!) influence decision-making around management of biodiversity outside cities. Therefore, the often limited experiences city-dwellers have with nature, such as seeing a tūi in their backyard, can greatly affect biodiversity outcomes. However, we also know that there is an increasing disconnect between people and nature as we become more urbanised. How many city-dwellers have visited a regional or national park in the last year? Reconnecting people with nature in the city not only benefits their mental and physical wellbeing, but can also have positive effects on how they value biodiversity and take action on conservation issues. The 2008 Erfurt Declaration also recognises the intrinsic value of urban ecosystems. Globally, urban areas can be hotspots for biodiversity – cities are often built in very fertile areas, and can be centres of evolution and adaptation.

Josie Galbraith’s project on the effects of backyard bird feeding on bird communities. Washing lines for hanging birds bags and deck furniture for banding and microchipping birds are a blessing for the urban researcher!

Josie Galbraith’s project on the effects of backyard bird feeding on bird communities. Washing lines for hanging birds bags and deck furniture for banding and microchipping birds are a blessing for the urban researcher!

There are a range of exciting and interesting research questions to be asked about biodiversity in cities. While some drivers of change are unique to cities, most are just modified versions of what’s happening outside cities (e.g. habitat loss) or are agents of change originating from cities (e.g. pollution, invasive species). My lab group are tackling questions, such as whether people feeding birds in their backyards can restructure urban bird communities, how light pollution might influence ecosystem function (eg. pollination) and how robust connectivity is for bird-dispersed plants within fragmented urban landscapes.

Two of the most frustrating things about urban ecology are: firstly, you can’t escape people (more social scientists please!); and secondly, there are no large, homogenous landscapes in which to put untold replicates. Experiments are critical for untangling drivers and interactions, but conducting experiments in urban landscapes can be very challenging: the high levels of variability over short distances, negotiating access to sites from many landowners/householders, and the high risk of vandalism to equipment. Even the main health and safety fieldwork issues are unusual: domestic dogs and dubious people, rather than getting lost in the bush or being injured far from a hospital. But if it all comes together, the results can be great. Watch this space within the next week or two for PhD student Josie Galbraith’s PNAS paper, where we report on our 18-month bird feeding experiment in suburban Auckland.

Road ecology research often requires the use of an orange flashing light on your car! Esther Dale (L) and Dr Cheryl Krull (R) during Cheryl’s postdoc research on rodent behaviour around roads.

Road ecology research often requires the use of an orange flashing light on your car! Esther Dale (L) and Dr Cheryl Krull (R) during Cheryl’s postdoc research on rodent behaviour around roads.

There’s also an unfortunate but realistic reason why urban ecology is attractive to ecologists. Science is getting more expensive, funding is declining, offshore islands and national parks are expensive to get students to. Urban ecology is a much better option in terms of science output/$ of funding. And then there’s the unexpected bonus of doing fieldwork in the city – the ability to order pizza for the cold, hungry field crew…

Pizza delivery to Josie Galbraith’s field sites

Pizza delivery to Josie Galbraith’s field sites

Dr 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 (particularly in terms of taxa), but can be grouped into three main research strands: urban ecology; invasion ecology; and plant-animal interactions. The most interesting and challenging projects are where these three strands overlap!

Vespula wasps inflict widespread economic and ecological damage

Posted by Jacqueline Beggs @JacquelineBeggs

Jacqueline

What do volcanic eruptions and invasive wasps have in common?

Mt Ruapehu erupting. Photo Craig Potton. http://www.prints.co.nz/page/fine-art/PROD/8973

Mt Ruapehu erupting. Photo Craig Potton. http://www.prints.co.nz/page/fine-art/PROD/8973

A recent study estimates that introduced Vespula wasps cost the New Zealand economy at least $130 million per year – equivalent to the estimated cost of the 1995-97 Ruapehu eruption.

The primary sector, particularly farming, beekeeping, horticulture and forestry bear the brunt of the economic impacts of wasps, but an already stretched health sector also shares the burden. The study did not attempt to quantify the economic impact on the tourism sector, although we know that encountering high densities of wasps puts off many people from outdoor recreation. Vespula wasps are invasive in many parts of the world, but New Zealand has the highest recorded density, not exactly our greatest claim to fame. However, I argue that the ecological impacts of wasps are far more damaging than the economic costs.

New Zealand has no native social wasps or bees, so the arrival of two species of Vespula wasp introduced a novel functional group into our ecosystems. I have spent many years studying the impact and control of wasps in South Island forests infested with endemic, honeydew-producing scale insects. Sugar-coated trees are surely a wasp’s idea of heaven. Native birds, lizards, insects and microbes all feed on honeydew, so when wasps monopolise the resource, many native species miss out. Additionally, wasps are predators of a wide range of invertebrates, attack nestling birds, and disrupt nutrient cycling.

Vespula wasps feed by trophallaxis - food gets passed around the colony making it a good target for control.

Vespula wasps feed by trophallaxis – food gets passed around the colony making it a good target for control.

Social insects are notoriously difficult to control – the social structure of colonies, high reproductive rates and dispersal ability makes management at the population level difficult. Biological control of wasps using Ichneumonid parasitoids has not been successful, although there are other potential agents such as Pneumolaelaps mites which might be more effective. Poison baiting using fipronil is very effective, but currently not commercially available. There are other options for wasp control such as pheromones or ‘RNA interference’ technology. Some of these may be developed as part of New Zealand’s Biological Heritage National Science Challenge, but don’t hold your breath for a single silver bullet arriving in time for next summer.

Unlike unpredictable, sporadic volcanic eruptions, I can reliably predict that for now there will be ongoing economic and ecological harm from Vespula wasps in those parts of the world they have invaded.

Dr Jacqueline Beggs is an Associate Professor in Ecology, School of Biological Sciences, University of Auckland.  She has failed to focus on a single topic; her research covers everything from impact and control of introduced invertebrates, to assessing the role of dung beetles and native bees in ecosystem function, and the recovery of grey faced petrels on a restoration island.

The Paturoa Kauri FAQ

Cate Macinnis-Ng

On Monday morning (9th March 2015) locals, conservationists and tangata whenua gathered at 40 Paturoa Road to protect a centuries old kauri tree marked for felling to make way for new dwellings on the property. Thanks to the efforts of these dedicated folk, the trees are safe (for now). So what is so special about this tree and why should we care about it being removed? Here I address several important questions about the value and significance of this tree and the surrounding vegetation.

Why are kauri trees so special?

Kauri are amongst the largest and longest-lived trees in the world. Tree enthusiasts travel from across the globe to see these majestic plants. Kauri have a special place in Maori cultural heritage because they are taonga species. They have an important role in the spiritual beliefs of tangata whenua and are viewed as chiefs of the forest and a living…

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An Experimental Mouse Invasion

Posted by Helen Nathan

New research by Helen Nathan, Mick Clout, Jamie MacKay, Elaine Murphy, James Russell

IMG_3884How much damage could a couple of mice do on a pest-free island? We used a novel experimental approach to demonstrate the importance of island biosecurity.

Two house mice (one male, one female) were released onto Te Haupa (Saddle) Island, a Department of Conservation scenic reserve which had previously hosted a mouse population, but had recently been declared pest-free. For the following 8 months we returned regularly to the island to undertake live trapping, allowing us to estimate the number of individual mice on the island, and plot the growth of the invasive population over time. We also took genetic samples from captured mice to confirm descent from the two founder individuals released. After 8 months, the experiment concluded and the population was eradicated using a combination of trapping and poison.

IMG_3916

Ear-punches were used to mark mice for identification and to provide a genetic sample

We found that population growth was initially rapid, peaking at an estimated 68 individuals 5 months after the release, then stabilising until the end of the 8 month experimental period. This pattern of growth reflects the classic model predicted by invasion biologists, but rarely observed in real-time as, in contrast to our study, the exact point in time when an invasion occurred is usually unknown. A surprise result from our genetic analysis showed that not all of the mice trapped at the end of our experiment were descended from the founding male and female. An unrelated female was first captured 3 months after the start of the invasion, and had produced offspring 1 month later. Genetic analysis suggests that this mouse most likely originated from another island off the north-east coast of New Zealand, almost certainly transported on a boat which had recently visited other nearby islands.

The extremely rapid population growth of the invading mouse population, along with the independent mouse incursion we detected, demonstrate the need for vigilant monitoring of our pest-free sanctuaries. For successful conservation and restoration of sites, invasive species populations must be detected early during colonisation to enable swift elimination, before the population becomes established.

Read the published research online now at Population Ecology http://link.springer.com/article/10.1007/s10144-015-0477-2

Or in the New Zealand Herald  http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=11399803

Helen Nathan is a PhD student in the Centre for Biodiversity and Biosecurity