Turning the black swan white: lessons from ‘Black Swan Theory’ on identifying and mitigating risks through collaboration

March 3, 2016March 3, 2016 / aucklandecology / Leave a comment

Posted by Rebecca Lehrke @rmlehrke

It would be pretty catastrophic – albeit unlikely – for a fire to sweep through your lab destroying all your research with it. On the other hand, forgetting to save the paper you are working on and so losing the last few hours of productivity, though slightly less painful, probably happens quite frequently to the best of us. Both events carry risks and have the potential of occurring. So which event is more important to prepare for or could collaboration remove the need to decide?

Understanding the balance between the probability of an event occurring and its consequence is important when managing wildlife. Take my current research topic for example – bird strike by black swans. Sparrows hit planes on a daily basis, but their impacts are usually minimal. Black swans on the other hand rarely hit planes. The difference is, when a black swan hits a plane the impact is equivalent to a Holden Commodore VE Sedan hitting a brick wall at least 15km per hour. This kind of impact can destroy a plane’s nose cone costing over $25,000, let alone the risks if it enters an engine. So what event should we be most concerned about?

Black swan (Cygnus atratus) pair with cygnets at Ambury Regional Park, Auckland.

Unfortunately, there usually aren’t simple answers to balancing risks, and in conservation biology, the survival of a species could be on the line. If we ignore high-risk but low-probability events an endangered species could go extinct because a 100-year storm event wipes out the last breeding pairs on an island. On the other hand, ignoring day-to-day impacts of resource supply could also lead to its extinction over time.

“The Black swan: The impact of the highly improbable” book cover.1

Economics has a long-standing concept that conservation and biosecurity managers could be using in these situations – Black Swan theory. According to Taleb ‘Black Swans’ are events that are unexpected, high impact and can often be explained or predicted in hindsight. Just like that 100-year storm event. Taleb warns that we could waste a lot of time – and money – trying to predict all these ‘Black Swans’. Instead our management plans should be robust enough to mitigate the negative impacts of unexpected events.

Although examples of such contingency plans being used in management programmes exist, it is often on an ad-hoc basis. This is where collaboration and synthesis across disciplines comes in. A devastating 100-year storm may not be common but if you know it is a natural part of the system, you can reduce its impacts, whether that means splitting your population across multiple islands or some other contingency plan.

As ecologists and managers we should always be discussing our study systems with our peers in different disciplines. As Taleb puts it, what the turkey may not see coming the butcher probably does. So let’s be the butcher not the turkey! Get another perspective, share knowledge and collaborate more often. It may not prevent a fire from sweeping through your lab, but seeing your lab from a fireman’s perspective might help you ‘identify’ these risks so you can ‘mitigate’ them by backing up off-site more often. Thus reducing the impacts and “turning the Black Swan white”₁.

Being the butcher, not the turkey. Retrieved from: http://bit.ly/1pn1vte

Rebecca

Rebecca Lehrke is an MSc student in the Centre for Biodiversity & Biosecurity, School of Biological Sciences, University of Auckland. She is using movement ecology to assess the efficacy of disturbance-based management of black swans at the Auckland Airport. She is supervised by Todd Dennis and Margaret Stanley.

Taleb, Nassim Nicholas (2007), The Black Swan: The Impact of the Highly Improbable, Random House, ISBN 978-1400063512

Science in shiny wrappers

February 25, 2016February 26, 2016 / aucklandecology / 1 Comment

Posted by Josie Galbraith @Josie_Anya

Something all scientists share is an inherent understanding that science is a worthy pursuit. That knowledge, like pie, is worth seeking. We are prepared to read paper after paper – countless paragraphs of text – for the betterment of our understanding. But even amongst ourselves, we usually draw the line at reading literature outside our fields of interest. And fair call – ain’t nobody got time for that. Papers outside our broad disciplines may as well be written by aliens. Alien subject matter, alien concepts, alien terminology. Crossing the disciplinary event-horizon doesn’t exactly make for easy digestion or light bedtime reading.

We all want sweet juicy visual treats.

Not paragraphs.

What we all want, what we really really want, is for someone to hand us delicious bite-sized science in shiny wrappers. Sweet juicy visual treats, like graphical abstracts, infographics and animations (check out this sweet as bird feeding animation – yeah you got me… it’s mine). Data visualization and visual storytelling aren’t new concepts, but in this digital age they have become more important than ever. Increasingly, journals across the spectrum are recommending or even requiring visual summaries of research. Visual representations of research are many more times effective at engagement than legions of characters lined up on a page (there’s a graphic of that). Do not underestimate the power of the drawn lines.

You’ve probably stopped reading already to check out this awesome graphical summary or #ArtStract from deciphered.com

What’s more, this kind of science is also perfect to share with all manner of non-sciencey folks. Science communication is, after all, a hugely important part of science and part of our responsibility as scientists (scidev.net editorial, Brownell et al. 2013 ). Not all of us are comfortable giving interviews via conventional channels (TV, radio, articles). Furthermore, mainstream media have a tendency to cover only those articles that are sexy, sensational, or published in the top journals. But, with the age of social media, opportunities for communicating science to the world in graphical ways have skyrocketed and we can do it ourselves. We don’t have to wait to be asked. Make the most of it. Turn your fancy words into shiny pictures, because pictures are great. Great for society and great for our own science.

Don’t wait to be asked.

Turn your science into a shiny picture today!

It is a vastly useful academic exercise to distill your research down into a single picture or a 60-sec animation. What is it that really matters about your study? What are the vital pieces? And these days we need to do more distilling. While opportunities to communicate science are increasing, attention spans are shrinking. Sharing scientific findings graphically is the perfect answer.

A final comment: don’t let artistic skill or lack thereof stand in your way. Graphics software is pretty awesome these days (your institution may already have a license for Adobe Illustrator, or there are many free apps too). Failing that there are people out there to help you with the research make-over you’re looking for (shout out to deSciphered and maybe future me).

Josie Galbraith is a PhD student in the Centre of Biodiversity and Biosecurity, School of Biological Sciences, University of Auckland. She is supervised by Margaret Stanley, Jacqueline Beggs and Daryl Jones (Griffith University, Australia). She is also known to dabble in the dark arts – painting, illustration, graphic design, and animation.

Science in wrappers image © Josie Galbraith. This image includes vectors designed by zhaolifang and larvarmsg Vecteezy.com.

Challenges of doing a PhD with a chronic disease

February 18, 2016 / aucklandecology / Leave a comment

Posted by Carolina Lara @carislaris

About 15% of the world´s population have some form of disability and this rate has been increasing (due to a multitude of factors), particularly for chronic health problems. Even though chronic conditions are more common than suspected, most people are not aware of what it is like undertaking a PhD while having one. And of course openly talking about it is not easy, because who likes to be seen as vulnerable and weak? So, it is likely that one of your colleagues might be experiencing this struggle but keeping it quiet.

An autoimmune disorder (most of them chronic) occurs when the body’s immune system attacks and destroys healthy body tissue by mistake.

I am now writing about my own Little Beast (as I have named my condition) as a way to raise social awareness about living with a chronic disease and studying for a PhD. I was diagnosed with a chronic autoimmune disorder called Ulcerative Colitis six years ago; eventually, this diagnosis changed to Crohn´s disease. There are all sort of personal challenges to face, especially because each individual and each chronic condition is different. The only similarities shared among chronic conditions are that despite treatment, they will not go away, and they will change our lives. And knowing that makes us experience anger, anxiety and depression. I am finally under remission thanks to a new medication but I am still battling fatigue caused by anaemia (because, well, medication has side effects). I am aware that this state will not last forever, unfortunately. And it has nothing to do with being pessimistic, it just the nature of chronic diseases.

Fatigue is a common symptom of autoimmune disorders & often becomes a limitation while doing a PhD.

No one warns us about how difficult doing a PhD can be, not only from an academic point of view, but from the personal pressure it conveys. Add this to a variable dose of daily physical discomfort and fatigue and it becomes unbearable at some point. There are good days, bad days and not-so-bad days. Getting up from bed can become such a challenge but also a great achievement. And yet, we will say we feel alright… but do we? Why can´t we just be honest and say “I feel terrible today, but despite that fact I am working”? Maybe because we only want to become, and be seen as, good scientists rather than “good scientists overcoming health struggles”.

Although this journey might seem lonely, support from family, friends, colleagues and supervisors play a big role. Against all odds, me and my Little Beast made it to New Zealand thanks to Margaret, my supervisor, who was happy to work with me even after warning her about my medical condition. I might talk more in detail about the personal and external challenges of living with a chronic disease in another post, but for now I might just take a nap.

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.

How many feral pigs did we kill? And why that’s the wrong question.

February 11, 2016February 11, 2016 / aucklandecology / 6 Comments

Posted by: Margaret Stanley @mc_stanley1 and Cheryl Krull @CherylRKrull

Too often pest control is focussed on the number of pests killed, rather than the actual benefits of removing the pests.

Most monitoring during pest management focusses on ‘results’ monitoring, which measures how many pests are killed during the control operation. However, the often forgotten, but more important type of monitoring is ‘outcome’ monitoring. This type of monitoring measures the true success of an operation by focussing on why the pests were killed in the first place. For example, outcome monitoring for a control operation targeting conservation damage by an herbivorous pest (e.g. brushtail possum) might be the ‘foliar browse index’ – which can indicate whether there is less damage to trees as a result of removing possums. The danger of only doing ‘results’ monitoring is that you’ll never know if you are achieving the biodiversity benefits you think you are. This costs money and the confidence of stakeholders.

stakerholders

The tide is starting to turn, with more investment in outcome monitoring. The key challenge is to link damage and damage thresholds to pest control operations. For example, some neat NZ research has shown that once you get above 4 rats per ha in podocarp forest, you start losing tree weta. Rat control operations can therefore be triggered at ‘damage thresholds,’ rather than undertaking regular control, saving money on pest control, and reducing the use of toxins.

This was our challenge posed by Auckland Council: we know feral pigs are causing damage to forest ecosystems, but how much feral pig control is enough? Feral pigs in dense temperate rainforests are notoriously difficult to count, and control is expensive.

Feral pig in rainforest. Photo Credit: Hawaii Volcanoes National Park

In our new paper, we report on how we used a 3-year pig control programme (ground hunting) to understand how control reduces pig densities, but most importantly, how pig control affects the rates of ground disturbance. We (the royal ‘we’ means Cheryl – as part of her PhD research) measured ground disturbance (rooting) by pigs throughout the Waitakere Ranges (Auckland, NZ) for the entirety of the hunting programme.

Feral pig rooting disturbance impacts. Photo Credit: Hawaii Volcanoes National Park

The control operation reduced the pig population by a third, but it reduced ground disturbance by more than half. When we simulated hunting regimes at different intervals, only the 3-monthly hunting interval achieved a constant reduction in ground disturbance. BUT, sending in hunting teams every 3 months is incredibly expensive and over time, starts to yield diminishing returns on that investment. Is a constant reduction in ground disturbance what we want? If managers switched to triggering control at unacceptable levels of ground disturbance (a disturbance threshold), would we still have worthwhile biodiversity outcomes?

So more appropriate questions for managers to ask rather than “how many pigs did we kill?” are “how much disturbance is too much?” and “when should we trigger feral pig control based on ecosystem damage?” One of the biggest issues for pest managers is the enormous cost of outcome monitoring. Getting clever about how we monitor and making sure we know what the monitoring means, is one of the challenges facing managers and scientists.

The next step in this story is about to happen. Masters student Robert Vennell is creating a density-impact function for feral pigs in forest. He’s trying to get to grips with how ground disturbance relates to the number of pigs detected on camera traps. Could this be a cheaper way to trigger control based on outcomes? Watch this space for his research story.

Feral pig detected by camera trap. Photo Credit: Patrick Garvey

RESEARCH PAPER: Krull CR, Stanley MC, Burns BR, Etherington TR, Choquenot D. 2016. Reducing Wildlife Damage with Cost-Effective Management Programmes. PLoS One DOI: 10.1371/journal.pone.0146765

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, but can be grouped into three main research strands: urban ecology; invasion ecology; and plant-animal interactions.

Dr Cheryl Krull is a former member of the Ecology Ngātahi lab group, completing her PhD on feral pigs and then as a postdoctoral fellow in the group. She is now a lecturer in the Institute of Applied Ecology New Zealand at AUT and is continuing her research into feral pig impacts and control, along with other conservation projects.

Harrowed sparrows and shrinking starlings

February 4, 2016February 4, 2016 / aucklandecology / Leave a comment

Posted by Sam Heggie-Gracie @SamHegGra

Birds are one of many taxa seen to be on the downslide globally, with 12% of all birds classified as threatened. Bird trends have been particularly well documented in Europe, and some of these studies have thrown up some interesting findings. In particular, it appears rarer birds are increasing in abundance, whilst the more common species are driving the brunt of the overall decline.

Spock’s famous adage “The needs of the many outweigh the needs of the few,” doesn’t normally apply in conservation, whereby common species are often overlooked in favour of protecting those that are rarer. It’s easy to take common species for granted. However, common species disproportionately influence the environment they live in as they form an especially integral part of the structure and function of their habitat. Commonality in ecology is (ironically) a rare trait, with only a few species lucky enough to have the right characteristics to multiply like nobody’s business and dominate an environment (think: humans). A decline of a once common species will be pretty bad news. In Europe, even the cherished, ever-present sparrows have taken a dive, as have starlings.

sparrow House sparrow (Image source: Fir0002/Flagstaffotos)

Some recent research has shown some of our own common birds such as tui may also be declining. Habitat destruction, invasive species and climate change pose threats to these birds, so it will be important to keep an eye on their populations.

By continuing to undertake informed bird-friendly actions (such as good bird feeding practices!), we can safeguard our inimitable native species from further loss. In terms of policy, a compact city as opposed to a sprawling one appears more favourable for bird communities, and this may be especially true for natives. Such city-scape planning alongside regular population monitoring may be increasingly required in order to mitigate biodiversity loss and assist both the many as well as the few.Silvereye (Image source: Fir0002/Flagstaffotos)

Check out Josie’s endearing video on good feeding practices, and remember to keep a close eye on your cat this summer as baby birds begin to emerge!

Sam Heggie-Gracie is an MSc student in the Centre for Biodiversity & Biosecurity, School of Biological Sciences, University of Auckland. He is investigating the drivers of bird composition in cities. He is supervised by Margaret Stanley and Cheryl Krull (AUT).

The pitfalls of Fiordland field work

January 28, 2016January 28, 2016 / aucklandecology / 2 Comments

Posted by Keely Paler @keely_paler

The first things that people say about Fiordland are that it’s a really beautiful place but the sandflies are the size of elephants. My recent trip to Fiordland proved they weren’t wrong. The sheer number of sandflies means that headnets are now my favourite fashion accessory. However the stunning-ness of the location more than made up for it.

In November, I went down to Te Anau, Fiordland to complete the first part of my master’s fieldwork. This adventure began with hastily rearranging flights to capture the best weather window. Because of New Zealand’s highly changeable weather this is an important part of ecological fieldwork in remote locations. Despite this planning, we arrived to an unexpected layer of snow, but these surprises are part of the fun of working in the field.

Open top chambers in alpine Takahe Valley, looking down to Lake Orbell

In order to get to our alpine study site in Takahe valley (in the Murchison Mountains of Fiordland), I had my first experience flying in a helicopter (a lot scarier than I imagined). This site is a particularly awesome place to conduct research because it’s where the ‘extinct’ takahe was rediscovered in 1948. Since this time it has been classed as a ‘special area’, accessible only to scientists and pest-control operators. This relatively undisturbed environment means it is an ideal place to study the effects of climate change on New Zealand’s unique alpine biodiversity. My master’s research will examine how insects respond to climate change using open-top-chambers to experimentally induce localised temperature increases). Insects are captured using pitfall traps, which will be collected during a second trip in March. Despite the sandflies, I can’t wait to go back.

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.

Growing old with caterpillars

January 21, 2016 / aucklandecology / 1 Comment

Posted by Zane McGrath

For the remainder of these summer months I will be searching far and wide for the kawakawa plant. It isn’t the odour emitted by its heart shaped leaves or berries I am attracted to, but the caterpillars hosted by the plant, which I will attempt to adopt and take back to their new home, the luxurious lab at Landcare Research. Although in highlighting the beauty of ecological research, and just to make things more confusing (see earlier posts by Sam and Carolina on ecological complexity), it is not the plant or the caterpillars that will be the main focus of my Masters research, but parasitoid wasps which emerge from the caterpillars.

The kawakawa plant (top) and kawakawa caterpillar (bottom)

Parasitoid wasps spend part of their life cycle within a host, such as a caterpillar, and basically eat their way out when ready to pupate, eventually killing the host. Fascinating or down right freaky (have a look for yourself in this video), parasitoid wasps have the ability to act as natural enemies for controlling agricultural pests. For my Masters research I will be focusing on whether Meteorus pulchricornis, a species accidentally introduced into New Zealand, is competing with native species for caterpillar hosts.

The culprit, Meteorus pulchricornis (Photo: iNaturalist.org) (top) and its cocoon hanging from a kawakawa plant, which is unique to the species (bottom)

In order to understand this, the caterpillars I collect will be reared until they reach their fate. If I’m lucky, but the caterpillar isn’t, a parasitoid wasp will emerge.

This is where I must hone my husbandry skills. The caterpillars can grow considerably over the period of a month or so before pupating. They will be fed their favourite meal, a kawakawa leaf that is replaced every five to seven days. However, as a parent would say, the growing up process isn’t always a pretty sight. Their homes can become inundated in frass (caterpillar poo), and need I say the larger the caterpillar grows, the larger the frass… but hey, it’s all part of being a parent.

Frass and a caterpillar

Zane McGrath is an MSc student in the Centre of Biodiversity and Biosecurity, School of Biological Sciences, University of Auckland. He is supervised by Darren Ward and Graham Walker (Plant and Food Research, Auckland) examining parasitism by exotic species in native environments.

Takahē folly

January 14, 2016 / aucklandecology / Leave a comment

Posted by Josie Galbraith @Josie_Anya

Among the many New Zealand conservation tragedies of 2015, there is one that stands out for me – the shooting of four takahē (Porphyrio hochstetteri; critically endangered) by members of the local Deerstalkers Association undertaking an authorized cull of pūkeko (Porphyrio porphyrio) on Motutapu Island in the Hauraki Gulf. It has been the source of much outrage and disgust, particularly in its being wholly avoidable. It seems impossible that takahē could have been in the line of fire, given that the hunters were instructed to shoot only pūkeko in flight… and takahē cannot fly…

While we wait to see if there will be any consequences for the buffoons who can’t follow instructions, I have contemplated this tragedy, seeking an explanation that is more fathomable. An explanation that stands to reason when one considers that the hunters were fully informed of takahē presence on the island and supposedly only shooting birds on the wing.

#thePuksAreVerySorry

‘Goodbye Puk Pie’ – Josie Galbraith

Celebrating one year of Ecology Ngātahi

January 14, 2016January 14, 2016 / aucklandecology / Leave a comment

Posted by the Ecology Ngātahi team @AklEcol

We’re turning 1! Image source: freelargeimages.com

Everybody loves a birthday! It’s a chance to reflect on the year that’s been and make plans for the year to come. Hopefully we are all a little bit wiser too!

In the spirit of reflection, we wanted to revisit some of the highlights on the Ecology Ngātahi blog from our first year. Undoubtedly, the stars of the show have been the postgraduate students and their research. The first student post involved Josie Galbraith bringing together urban birds and teenage mutant ninja turtles. Animated characters were a common theme with Ant-Man and Batman also featuring in posts by Anna Probert and Ellery McNaughton.

Another popular theme was fieldwork. Sam Lincoln, Sam Heggie-Grace and Julia Kaplick shared their experiences as field ecologists. Other experiences shared were Jamie Stavert’s piece on his time in Europe and Carolina Lara’s piece on her experiences as an international student in NZ. Also, Anna Probert learnt all about ants and had fun doing it on her ant course. These three posts make interesting reading for anyone planning on spending time overseas. Something else any ecologist can relate to is frustrations with R and Jessica Devitt suggested some valuable resources she has discovered.

Other more quirky posts included Lloyd Stringer on NZ as a source of invasive species and Rebecca Lehrke’s experiences monitoring swan activity near the airport. Jamie Stavert wrote a fabulous post on the joy of creativity and Alice Baranyovits made a call for citizen scientists to get involved with her kereru project.

The most popular post by far was Jacqueline’s piece on kākāpō. It seems everyone loves a good news story! Cate’s tips for scoring a postdoc were widely shared on twitter. Margaret’s blog on the importance of urban ecology was another popular read and Mick explained the strange case of high genetic diversity in NZ stoat population.

So, it’s been a fascinating and wide-ranging year. I don’t think we expected to cover so many different topics when we started out last year. We have exciting plans for 2016. We welcome Darren Ward onto the Ecology Ngātahi team and we have a great bunch of new students and great projects. We’ll be continuing with weekly posts to highlight student research and topical issues in Ecology. We have recently launched our youtube channel so do look out for more clips about our research and don’t miss Josie’s animation on the impacts of feeding birds. Another new addition is our publications in a nutshell page where we will be posting brief summaries of new publications.

Thanks to you, our readers and followers for engaging with our work. We have had hits from over 110 countries with over 6000 unique visitors (hello world!). We appreciate you taking the time to have a look at the blog and share our stories on twitter and facebook.

Tau Hou hari! Happy new year!

Potential threats on the horizon for urban ecosystems: the top 10

December 3, 2015January 21, 2016 / aucklandecology / 1 Comment

Posted by Margaret Stanley @mc_stanley1

In an earlier blog (What’s the Point of Urban Ecology?), I talked about the importance of urban ecosystems – both for connecting people with nature, and for their intrinsic values. Cities can be biodiversity hotspots!

Maximising biodiversity in the streets of Paris

There are the usual suspects that come to mind when we consider threats to urban biodiversity: human population increases, intensification, climate change, etc. But are there any new threats on the horizon that we should be looking out for in cities? With this in mind, we applied for funding for a horizon-scanning exercise to identify emerging threats in urban ecosystems (thanks CBB!). Horizon-scanning is a systematic search for issues that are not widely recognised – either in the research literature or in policy.

In January of this year, we brought together 12 participants from Australia, UK and New Zealand for the horizon scanning workshop. We based the workshop on the well-known conservation horizon scanning workshops led by Prof. Bill Sutherland. Before coming to our workshop, we used our professional networks to gather ‘emerging threats’ from colleagues in science, policy and management. During the workshop, we explored, debated and ranked the 137 potential threats that were suggested by the global experts.

Debating the issues during the horizon-scanning workshop

The key to this exercise was to identify threats that were truly on the horizon, rather than one of the ‘usual suspects’. It was remarkably difficult to really pull out those ‘good grief’ moments as Prof. Kevin Gaston called them – the potential threats that truly surprised us. The workshop was a refreshing opportunity to do something we scientists rarely get an opportunity to do – delve into issues completely outside our knowledge set. Who would have thought we’d be trying to figure out what human ‘cremains’ are composed of? Or google-searching ‘self-healing concrete’?

The paper resulting from the workshop has been published in Frontiers in Ecology and the Environment. The final list of potential threats (see below) included advances in technology, as well as issues around how people are using green spaces. It is important to recognise that although we’ve identified potential threats associated with new technology, some of these new technologies also bring a range of environmental benefits (e.g. solar panels). The main purpose of horizon scanning is to identify potential threats early, so we can assess whether they really are a threat, and if so, mitigate the threat proactively. It’s possible that just ‘tweaking’ a piece of technology would reduce its impact on urban biota, while maintaining its effectiveness.

So what’s next on the horizon?

Ecologists are often accused of being negative (or even “scare-mongering” to quote a journalist who interviewed me this week) – perhaps our next horizon-scan should search for emerging opportunities for urban ecosystems. That sounds like a much more inspiring workshop!

In the meantime, we hope to inspire researchers to explore how much of a threat these 10 issues are, and to inspire policymakers and managers to look ahead to threats on the horizon.

TOP 10 Potential threats:

Maximising biodiversity in the streets of Paris

Health demands on greenspace: As more people are encouraged to use green urban spaces for exercise, these spaces can become highly maintained for people rather than wildlife; with more tracks, artificial lighting and fewer plants.

Figure 2b Digital replacement of nature: There is a risk that nature in cities could be replaced with digital equivalents of nature, such as images and sound recordings. This gives people some of the benefits of nature, but without the maintenance and messy side of nature, however it could lead to city dwellers undervaluing nature in their immediate environment.

Scattered cremains (material resulting from cremation): There has been a growing trend for cremation as space for burial of human remains is at a premium. However, in some cities land for interring cremains has become very expensive and scattering cremains has become more culturally acceptable. Because of high levels of phosphate and calcium in cremains, there is a risk of polluting urban ecosystems and waterways.

Spread of disease by urban cats: Globally, there are now more than 600 million pet cats, and the increase in pet cat ownership is resulting in the disease toxoplasma spilling over into wildlife populations, in urban areas as well as to species in more remote locations, such as the endangered Hector’s dolphin.

Figure 4a Switch to LED lights: Cities across the globe are switching their lighting technology to LED lights. However, the whiter spectrum of LED lights overlaps with the visual systems of wildlife and can disrupt their physiology and behaviour.

Solar cities: Many cities are implementing city-wide solar panel installation programmes. However, solar panels can disrupt the behaviour and reproduction of animals that are attracted to the polarised light they produce.

Nanotechnology: Nanoparticles (e.g. graphene) are now an increasing but invisible part of cities, found in everything from smartphones to clothing. However, there has been almost no research on the effects of these particles on animals, plants and entire ecosystems.

Self-healing concrete: This is a new concrete product infused with specialised bacteria is about to be commercialised. If use of this product becomes widespread, it could spell the end for the often unique biodiversity that currently manages to thrive in cracked concrete all around cities.

Energy efficient homes: Many countries are implementing large-scale retrofitting of buildings to make them more energy efficient. However, this effectively seals the building off from the outside, resulting in loss of breeding sites for wildlife such as bats and nesting birds.

Drones: The recent popularity of using drones (unmanned aerial vehicles) in cities is likely to result in issues for wildlife, such as nesting birds, which are particularly sensitive to stress and repeated aerial disturbance.

Click here for the paper:

Stanley MC, Beggs JR, Bassett IE, Burns BR, Dirks KN, Jones DJ, Linklater WL, Macinnis-Ng C, Simcock R, Souter-Brown G, Trowsdale SA, Gaston KJ. (2015). Emerging threats in urban ecosystems: a horizon scanning exercise. Frontiers in Ecology & Environment, 2015 13(10): 553–560, doi:10.1890/150229

Ecology Ngātahi members Jacqueline Beggs and Cate Macinnis-Ng were part of the Horizon-scanning exercise and are co-authors on the paper.