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GEE Science Uncovered

Claire Asher7 October 2013

On Friday 27th September, scientists in 300 cities across Europe got together with the public for a variety of activities and events to celebrate European Researcher’s Night 2013. In London, the Natural History Museum kept their doors open late for ‘Science Uncovered’ – an evening of special exhibitions, stalls and activities, engaging the public with researchers from universities and academic organisations across the capital.

Together with researchers from the Natural History Museum and UCL’s Department of Geography, academics from GEE displayed some of their work and chatted to the public about environmental change. GEE staff and students including Professor Georgina Mace, Dr Sarah Whitmee, Claire Asher and Stuart Nattrass, along with Sara Contu from the PREDICTS Project and Robin Freeman from ZSL, chatted to members of the public about their thoughts on environmental change and biodiversity loss.

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We are now becoming increasingly aware of the rapid climatic changes that are taking place globally, and with the release last week of the latest IPCC report, the climate has been a major talking point. Environmental change, including climate and land-use, will influence both us and the biodiversity with which we share our planet. Some animals may be able to adapt to climatic changes, but these will act in combination with human activities and land-use to influence which species persist and which perish.

PREDICTS Game NHMAs part of the GEE Environmental Change Stall, in collaboration with the PREDICTS Project, and ZSL, Claire Asher and Robin Freeman developed a game to test the public’s perceptions of present and future environmental change and biodiversity loss. Participants were asked to make a guess about future environmental change under two scenarios – a low-emissions scenario in which land-use decisions are based primarily on the agricultural value of the land, and a high-emissions scenario in which emissions pricing influenced land-use decisions. Predicted levels of global biodiversity were estimated up to 2100 using the PREDICTS model and well recognised scenarios of climatic warming and land-use change. The game proved very popular, with nearly 50 players during the night, competing to achieve the best score.

DSC06144 copyThe answer was not as simple as many of our players might have expected. Because climate does not act alone to influence species extinctions, land-use and other aspects of each scenario also played a major role. In the high-emissions scenario, emissions pricing (an attempt to minimise further warming) encouraged the preservation of primary forest, mitigating some of the negative effects of climate change on biodiversity. Meanwhile, in the low-emissions scenario, continued loss of primary forest in favour of agricultural land, particularly for the production of biofuels, meant that biodiversity suffered more than we might have thought from climate warming alone. Our decisions about emissions, land-use and conservation policies will have a far-reaching effect on global biodiversity.

The Future of Biodiversity game will be available to play online soon!

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Award-Winning Bat Conservation

Claire Asher16 September 2013

This year’s Vincent Weir Scientific award for bat conservation biology has been awarded to GEE’s Charlotte Walters for her PhD work on the iBatsID tool.

The Vincent Weir Scientific Award is an annual award given to a UK-based student for their outstanding contribution to the conservation biology of Bats. It is awarded by the Bat Conservation Trust (BCT), a national organisation devoted to the conservation of bats and their habitats within the UK. Charlotte Walters, who recently completed her PhD with the Zoological Society of London (ZSL), University College London (UCL), University of Kent and BCT, has been awarded the prize for her contribution to bat conservation and particularly her work for the Indicator Bats Program (iBats).

iBats is a partnership between ZSL and BCT, aiming to monitor global changes in bat biodiversity and provide valuable data for policy makers and conservation groups. They provide training and equipment to projects monitoring bat biodiversity to ensure standardised methodology which will enable global comparisons. They have also developed a number of free tools for iPhone and Android which enable fast, simple and efficient detection and identification of bats, and Charlotte’s iBatsID program is a key part of this.

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Image Credit: Gilles San Martin, used under creative commons licence.

During her PhD, Charlotte developed the iBatsID tool, an automatic tool for acoustic identification of European bat ecolocation calls. The tool is able to identify 34 different species of bat based on their calls alone, and is enabling scientists to achieve consistent monitoring of bat populations across Europe. The tool uses ensembles of artificial neural networks to classify bat echolocation calls and identify which species or group the call belongs to. Dr Karen Haysom (Director of Science, BCT) says “New tools and techniques to assist monitoring help us find out more about these fascinating and vulnerable creatures, [and] Charlotte particularly impressed the judges with the innovation and technical quality of her research”.

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Bats are ecologically important, playing a key role as predators and seed dispersers. They are also very sensitive to human activities, and are useful as ‘indicator species’ for monitoring biodiversity patterns in general. In Europe, all 52 species of Bat are protected by law as part of the “Agreement on the Conservation of Populations of European Bats“. However, being nocturnal and generally small, they are difficult to detect visually or by trapping. Recording bat calls can allow researchers to survey difficult habitats and gain a clearer picture of what bat species are present and in what numbers. But a standardised statistical method for identifying the species of bat based upon it’s call was needed. This has previously been difficult to achieve, but the recent publication of a global library of bat calls, EchoBank, enabled this type of large-scale identification project to be attempted.

Bat calls vary between species and have been shaped by natural selection relating to species’ ecology. However, calls also vary between individuals within a species according to sex, age, habitat and geographical location, and social environment. Bats also vary their calls depending on what they’re doing – calls are longer when a bat is searching for prey and become shorter as it narrows in on it’s target. So, identifying a species by it’s call is a little more complex than one might expect. Charlotte developed an artificial neural network which was trained on calls of known species and can then be used to identify new calls recorded in the field.

Example of an Artificial Neural Network
Image by Chrislb, used under creative commons licence.

Artificial neural networks are computer models inspired by the central nervous system of animals. They are represented as an interconnected set of ‘neurons’, each of which makes simple calculations which together generate complex behaviour. Artificial neural networks are ‘trained’ first and this training determines the simple algorithms performed by each neuron. The trained network can then be used on real data. In the case of iBats, this involves training the network using calls for which the bat species is known, and the finished neural network can then be used to estimate which species an unknown recorded call belongs to. ANNs are a form of computer learning, and will improve in their accuracy with training – the network of neurons is able to ‘learn’ from it’s mistakes and refine the algorithm to improve classification. This method proved to be highly accurate; 98% of calls from 34 species can be accurately classified into a ‘call-type’ group, and 84% can be classified to species-level.

The iBatsID tool is freely available online, enabling researchers to utilise a standardised methodology for identifying bat species across Europe. This will facilitate large-scale comparative studies and will be particularly useful for studying European bats that have a large geographical range or are migratory. This data will be important for making conservation decisions for the future, and is therefore crucial for bat conservation but also for biodiversity monitoring in general, as bats can provide an accurate assessment of the health of entire biological communities.

Original Article:

() Journal of Applied Ecology

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This research was made possible by funding from the Natural Environment Research Council (NERC) and the Bat Conservation Trust

The Global Future of Consumption

Claire Asher30 August 2013

The ever-growing human population, our increasing consumption of natural resources and our environmental impact, are a major concern. However, population growth and consumption varies dramatically from country to country and therefore our predictions of what the future may hold are also likely to differ between nations. Recent research in GEE used mathematical models of different population scenarios over the next 100 years to investigate the relative importance of curbing consumption and population growth.

In 1800, the global human population reached 1 billion, and by 2011 it had soured to seven times that. Although population growth is now slowing, current UN projections suggest that we will have reached 10 billion by 2080. Meanwhile, lifespan has tripled in the last thousand years while reproductive output (number of children) has halved worldwide, meaning many regions now have aging populations. However, there is considerable variation in this between countries and regions. In particular, developing nations tend to have higher mortality and higher birth rate. As countries develop and mortality decreases, they undergo what is known as the ‘demographic transition’, moving towards a lower birth rate as is observed in developed nations now.

As population size increases, so do our demands on the environment. We are now undergoing global climate change, environmental pollution and loss of species, although these magnitude of these changes is heterogeneous across the globe. In general, while birth rate tends to decrease with population size, consumption per capita increases. This pattern is not sustainable, and resources are becoming an increasingly limiting factor for development, especially to the world’s poorest nations. Reduced pressure on the environment can only be achieved through either reducing the number of people, or reducing the consumption of resources per person. Reductions in population growth rate or consumption may therefore be able to mitigate these effects over coming decades, however the effects of changes in birth rate, demography, consumption and efficiency are unlikely to be uniform across the developed and developing world. To investigate this, Professor Georgina Mace and Dr Emma Terama from UCL and Professor Tim Coulson from the University of Oxford modelled consumption in the USA and India over the next 100 years under different scenarios. Reductions in both birth rate and emissions are needed to stabilise global consumption over the next century. A 1% reduction in both birth rate and C02 emissions over the next 50 years would be sufficient to achieve stability, however the impact of different scenarios varied between developed (USA) and developing (India) countries. In particular, short-term benefits are associated with reducing consumption in high income countries such as the USA, but long-term gains can be achieved through early reductions in population growth in developing countries.

The effect of changes in population growth are slow to become apparent, especially in young populations where there can be a considerable lag. However, early reductions in population growth yield substantial benefits in the long-term. By contrast, reductions in individual consumption in high-income countries can have a very rapid impact on national consumption, and may be easier to achieve in countries fitting this profile. Steps to reduce consumption now in countries such as the USA and the UK may be important in securing long-term global sustainability.

The world’s resources are rapidly becoming a limiting factor for our growing population. Reductions in per capita consumption, achieved through lower consumption or improved efficiency from technological innovations, can yield immediate benefits in reducing environmental pressures in developed countries. By contrast, long-term benefits can be gained through early reductions in population growth in developing countries. Understanding the dynamics of growth and consumption in relation to current and future development and demography is crucial if we are to plan for the future and act to minimise our impact on the global environment.

Original Article:

() Environmental and Resource Economics

Predicting the Future of Biodiversity

Claire Asher14 August 2013

As human populations expand and use the land differently, they are having an impact on the plants and animals that share that land with them. Conservation biologists have been working for decades to try and document the ways in which these changes are affecting species, and to try and develop indicators that can be used to monitor these changes over time. However, previous work has tended to focus on certain species (e.g. bats, birds), neglecting other important groups such as insects, and have been biased towards certain habitats (e.g. tropical rainforest).

A new project in partnership between University College London, Imperial College London, the University of Sussex, UNEP World Conservation Monitoring Center and Microsoft Research, aims to improve on previous studies and develop a model for understanding how whole biological communities respond to human pressures across the globe. Collating high-quality data from hundreds of peer-reviewed papers, in addition to unpublished data direct from field researchers, the PREDICTS team hope to investigate local patterns of biodiversity at a global scale, and improve our understanding of how whole ecosystems respond to human pressures such as land-use change.

Biodiversity Declines
IMG_5921Major global loss of biodiversity is underway, and we have good reason to believe humans are responsible. The current extinction rate of species is estimated to be 1000 times higher than long-term historical averages, although large fluctuations in this in the past were also common. Humans have altered the world enormously, converting forests and savannas into farmland and housing. Virtually all ecosystems have been changed substantially – most biomes have lost between 20 and 50% of land to human uses. Humans have also exploited natural resources for wood, food, medicine and social reasons, and in many cases overexploitation has lead to major species declines and extinctions. Globally, it is estimated that 12% of bird species, 23% of mammals and 32% of amphibians are threatened with extinction, with many of these species suffering population declines and a reduction in genetic diversity, which may exacerbate the effect of human impacts. Even optimistic projections indicate continued human pressure on biodiversity from a range of different sources including hunting and habitat destruction. Many of the pressures currently placed on global biodiversity, such as land-use change, pollution and the introduction of invasive species, are set to continue or intensify over coming decades.

Ecosystem Services
Biodiversity is a valuable asset to humans for many reasons, not least its considerable economic value. Biodiversity contributes to human well-being by providing ecosystem services such as food (crops and livestock), fresh water, timber, natural hazard protection, air quality, climate regulation, prevention of erosion, as well as cultural benefits such as the aesthetic and recreational use of biodiversity. The exact relationship between biodiversity and ecosystem services is still relatively poorly understood, as it represents a complex interaction of many factors, which may vary from habitat to habitat. Many researchers suspect there may be threshold effects, with a sudden collapse of ecosystems, and a consequent loss of the services they provide, once a threshold number of species is lost. Others suggest certain ‘keystone’ species may be more important for ecosystem function. What is clear, however, is that healthy, functioning ecosystems are key to human health and well being. A greater understanding both of how biodiversity contributes to ecosystem function and ecosystem services, and of how biodiversity is likely to respond to continued anthropogenic pressures is sorely needed.

Improving Indicators
DSC_1216_watermarkOne central issue to studying and increasing our understanding of how ecosystems respond to human pressures is selecting species, populations or ecosystems to act as indicators of overall trends. It is simply not possible to monitor all populations of all species, and conservationists have traditionally relied upon indicator species and ecosystems as a measure of the overall health of biodiversity. In many cases these indicators were initially selected out of convenience meaning that well-studied species, communities and biomes are hugely overrepresented in the data available. However, species’ traits are likely to influence how they respond to human pressures, and a broader geographical and taxonomic view is needed to take the next step in our understanding.

Projecting Responses of Ecological Diversity in Changing Terrestrial Systems
The PREDICTS project aims to address some of these issues by performing a meta-analysis of species responses to different human pressures, covering as broad a taxonomic and geographical data set as is available. The PREDICTS team are collecting data from published papers; however, they also hope to draw on rich datasets held by ecologists which are simply too large to have been published in full. If you are an ecologist and believe you may have data that could be used for this project, please visit the PREDICTS website to find out more. They have already collated over 800,000 biodiversity records covering more than 15,000 species. These data are being combined to form a database that will be used to answer a number of key questions about biodiversity and anthropogenic change. In particular, the PREDICTS project is interested in investigating how different taxonomic groups respond, how responses differ in different biomes and with different intensities of human pressure. They also plan to investigate how different measures of biodiversity (e.g. species richness, evenness, abundance etc) may respond differently in different species, regions and for different human pressures.

_DSC3418_watermarkBy combining data from many species and sites, across a variety of different intensities of human pressure, PREDICTS hopes to develop a deeper understanding of how different factors interact to determine species responses. From this they hope to make predictions about how biodiversity may respond to different projected future scenarios, and thus provide insights for science policy.

Turning Science into Policy
We are faced with an increasingly difficult global situation, as human populations expand, the climate changes and biodiversity declines. What makes this situation more difficult still is that we need to make decisions now and over the next few years that will impact a generation, but for which we still have insufficient data to know for sure what’s best. Making projections for climate change, human population expansions and changes in the exploitation of biodiversity is difficult. Making projections for how biodiversity will respond to those changes is even more difficult still, but it is a task we must attempt if we are to make informed decisions about the future of our planet. PREDICTS hopes to utilise what data we do have to make synthesise a more in depth and holistic understanding of how ecological communities respond to human impacts, which can be used to make predictions that will help inform science policy makers globally.

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Images copyright Lawrence Hudson and Tim Newbold, used with permission.

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University College London
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United Nations Environment Programme: World Conservation Monitoring Centre (UNEP-WCMC)
Microsoft Research

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Ecosystem Services and Agriculture – An Integrated Approach to UK Policy

Claire Asher9 August 2013

Nearly three-quarters of the UK is agricultural land and decisions about land use fundamentally effect all of us through their effects on the cost and availability of food, pollution and climate change, and the availability of land for other purposes such as recreation and housing. Traditional strategies for determining land-use are based on the market value of the produce, ignoring the value of ecosystem services and variability of the environment across the UK. However, ignoring these factors will lead to economic losses by 2060, recent research in collaboration between the University of East Anglia and University College London reveals. Future policy must account for the total value of land, and apply policy in a non-uniform way in order to maximise the long-term benefits of our land-use decisions.

The UK is one of the most altered ecosystems in the World, and its land is dominated by agriculture. Nearly 75% of UK soil (that’s 18.4 million hectares!) is agricultural. Decisions about how to use our land have traditionally used a one-size-fits-all, market-driven approach, but recent research in UCL’s GEE and UEA’s CSERGE indicates this might not be the best approach for maximising long-term benefits.

Using data from a variety of sources, including the UK National Ecosystem Assessment, which generated a fine-scale dataset of land-use records in the UK covering a 40-year period, UCL’s Professor Georgina Mace, Professor Ian Bateman and collegues at UEA modelled the future of UK land-use, considering the heterogeneous value of whole ecosystems under different climate change and policy scenarios. The models included environmental variables (soil type, slope, temperature and rainfall), policy variables (subsidies, tax and constraints), market forces and technological advances, under a range of climate scenarios until 2060. Considering purely the market value of produce, a policy of weak environmental regulation was favoured, but this was not the case when the value of ecosystem services such as reduced green-house gas emissions and recreational land-use were considered. For the UK as a whole, the greatest net gains were achieved under stricter environmental regulation. In particular the ‘nature at work’ policy scenario, which considers whole ecosystem function and prioritises recreational green-space in urban environments, produced the largest net gains.

However, the pattern of gains and losses in the monetary value of land varied across the country, with weaker environmental regulation favoured in north west Britain. They therefore also considered models which allowed policy to vary across the UK. Selecting a policy scenario for each area based on both market value and ecosystem services yielded net benefits of 20% across the UK, with much larger gains in highly populated areas. Converting relatively small areas of land towards recreation and green-space was of extremely high value in urban areas, at a relatively small cost to agriculture.

One interesting finding was that applying conservation priorities came at minimal cost. As well as investigating ecosystem variables with a measurable market value (e.g. green house gas emissions), they also considered more abstract factors such as biodiversity. Imposing restrictions which minimised biodiversity loss rarely influenced the best policy scenario, and resulted in only minor reductions in economic gains. This suggests that with an integrated approach to policy-making, we can achieve conservation priorities with minimal impact to our economic prosperity.

Overall, the best strategy for the future of UK land-use will be an approach that considers the total value of land, rather than just the market value of agricultural produce, and one that considers different regions separately based on environmental characteristics such as soil type, temperature and rainfall. However, these types of changes may be difficult to implement; the most beneficial land-use strategy may not be privately beneficial for the land manager, and geographically variable policy is more administratively complex. The authors suggest that reform in the European Union’s Common Agricultural Policy (CAP) would improve the effectiveness of land-use policy. Currently, CAP pays more than £3 billion a year in subsidies to UK farmers, with little consideration to environmental performance. Switching to a Payment for Ecosystem Services (PES) system that rewards farmers for a variety of ecosystem services could allow policy-makers to achieve beneficial land-use change in the long term.

The fate of the UK landscape has traditionally been directed by the agricultural market, without attention to the value of ecosystem services. However, in a paper last month in Science, researchers at the University of East Anglia and University College London presented computer simulations based upon extensive data for the UK, which indicated this policy will not make the best use of our land over the coming decades. Instead, a system of increased environmental regulation tailored specifically to different geographical areas would maximise the monetary value of our land, and enacting conservation priorities within this framework comes at minimal cost.

Original Article:

Images © Copyright Pam Brophy and licensed for reuse under this Creative Commons Licence. Part of the Geograph Project

This research was made possible by funding from the UK-NEA and its Follow-On program, which are together supported by UK Defra, the Natural Environment Research Council (NERC), the Economic and Social Research Council (ESRC) and the Social and Environmental Economic Research (SEER) project.

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Summer Science Events

Claire Asher17 July 2013

July has been an exciting month for science shows – The Royal Society Summer Exhibition ran from the 2nd to the 7th at Carlton House in London, and on Friday 5th July, Soapbox Science took to the south bank for it’s third annual event celebrating women in science.

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Technology for Nature. Dr Robin Freeman (UCL, ZSL) demonstrates Mataki technology

At this year’s Royal Society Summer Exhibition, Technology for Nature, a joint project between UCL, Imperial College London, Microsoft Research and the Zoological Society of London, held a successful stall demonstrating a number of applications of technology to ecology and conservation. A particular highlight was the demo for Mataki, a new tracking technology which can detect behavioural information as well as locational information from a small tracking device attached to an animals back. This technology is being used to monitor the movement and foraging behaviour of sea birds. Professor Kate Jones and Dr Robin Freeman were amongst demonstrators during the week, talking to the public.

“We have a pressing need to better assess the behaviour, distribution and status of many species, and new technologies provide new ways to achieve this. From recording the dynamic behaviour of animals in the wild, to better assessments of distribution and diversity – within the Technology for Nature unit we’re developing and using new technological innovations to understand the natural world on which we rely.”
– Dr Robin Freeman (UCL CoMPLEX, Zoological Society of London)

Now in its 10th year, the Royal Society Summer Science Exhibition is an annual event showcasing cutting-edge research from around the UK. Each year, teams of scientists congregate in London hoping to demonstrate and communicate their science to the public, to students and fellow scientists, to policy-makers and the media. With interactive demonstrations, along with evening events and talks, the Royal Society Summer Science exhibition is a highlight of the year. This year, 24 Universities were selected to bring their scientific innovations to the exhibition, covering topics as diverse as dark matter, glacial melting, antibiotics and ecological monitoring. UCL’s Technology for Nature, in collaboration with Imperial College, ZSL and Microsoft Research, demonstrated three of their innovative projects aiming to apply technological advances to ecological problems.

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One of the highlights of the Technology for Nature stand was the Mataki demonstration, that had members of the public step into the shoes (wings?) of seabirds to test out the revolutionary technology that can not only track animals, but also monitor behaviour. The small, light weight, economical tracking device produces data that enables different types of flight and foraging behaviour to be identified.

Robin Freeman, a research fellow in UCL’s CoMPLEX and head of the Indicators and Assessments unit at ZSL, helped develop the technology: “The Mataki platform provides an open, low-cost tool that researchers can use to record animal movement and behaviour in the wild. By providing a powerful tracking technology in a small, low-cost package, I hope that more researchers are able to gather the rich data that we need to understand the changing behaviour of animals in the wild.”

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Professor Kate Jones (UCL, ZSL) and Dr Robin Freeman (UCL, ZSL) engage with the public to demonstrate Technology for Nature

Professor Kate Jones, from UCL’s Center for Biodiversity and Environment Research, has been working on a number of projects aimed at improving the ease of detecting and identifying bats, and utilising crowd-sourcing as a means to tackle large data sets generated by such technology.

“Developing easily accessible tools with which to identify wild species is critical to engage more people with the natural world and to monitor any changes. Imagine a world where you could hold up your smartphone when you hear a bird call and it would identify the species – like a Shazam app for biodiversity. We are still a way from that point yet but we are progressing with such tools for bats where the first stage is to develop an online tool that can identify bat echolocation calls. We are now developing that into a smartphone application”
– Professor Kate Jones (UCL CBER)

Find out more about the Technology for Nature project.

Soapbox Science

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Julie Dunne (Bristol University)
talking about the history of dairy
consumption.

As the long awaited summer finally arrived in London, so did 12 of the UK’s top female scientists, ready to communicate their science to the public in one of London’s most unusual science events – Soapbox science. Here, scientists are challenged to enthuse, entertain and educate a diverse audience about their research, without the aid of powerpoint slides and scientific jargon. Armed with nothing more than a few props, a Soapbox and a lot of enthusiasm, this years inspiring female scientists were challenged to explain their research to the public.

Soapbox science is a collaboration between the Zoological society of London and L’Oréal-UNESCO For Women in Science, which aims to highlight the struggles faced by women pursuing a career in science and challenge the public’s view of women in science. Soapbox science was created by Dr Seirian Sumner and Dr Nathalie Pettorelli, hoping to inspire a new generation of female scientists.

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Professor Laura Piddock talks about antibiotic resistance, and Dr Emily Cross demonstrates how the human brain perceives complex movement.

Co-organiser, Dr Nathalie Pettorelli (Zoological Society of London) says: “Now in its fourth year, Soapbox Science is a platform to showcase the most eminent female scientists in the UK, and to highlight some very serious issues that we have witnessed as mid-career scientists: the disappearance of our female peers”. Dr Seirian Sumner (Bristol University) adds “Through events like Soapbox Science and our Campaign for Change, we want to actively bring women of all career stages together and promote that women can have a career in science”.

This year’s Soapbox scientists covered topics ranging from gut bacteria to the neuroscience of dance, from computing to antibiotics. Find out more about Soapbox Science

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Soapbox Science in Gabriels Wharf. Dr Zoe Schnepp (University of Birmingham) explains superconducting seaweed and green nanotechnology.

The Dynamics of Population Declines

Claire Asher2 July 2013

Widespread declines in wildlife populations are a major concern, but global and regional targets to reduce the rate of biodiversity loss have so far not been met. Conservation practitioners are faced with an increasingly difficult task of balancing limited funding against increasing human pressures on wild populations. Methods for identifying detrimental human activities, identifying and classifying declines and prioritising species for conservation interventions are critical to ensure conservation efforts are invested wisely over the coming decades. Researchers at the Institute of Zoology (IOZ), Imperial College London and GEE have been working towards developing innovative methods for identifying pressures and determining conservation priorities in wild mammal populations.

Theoretical work suggests that different human pressures may result in different types of population decline, leaving a fingerprint of anthropogenic stress on the history of a population. Human activity might cause a constant pressure, or one that changes in proportion to the abundance of a species. Pressures may become more extreme as populations become smaller, for example when the value of a species to hunters increases as it becomes rarer. By contrast, a constant hunting effort would create a declining pressure over time, as individuals become increasingly difficult to find. Previous work by CBER’s Georgina Mace has suggested that the shape of the population decline curve observed may be characteristic of certain types of human pressure. A recent paper in Ecology and Evolution by IOZ’s Martina Di Fonzo, and Ben Collen and Georgina Mace from GEE, uses computer simulations and long-term monitoring data from nearly 60 species of mammal worldwide to test these theoretical predictions.

Different Population Decline Curve Shapes for Different Types of Human Pressure

Different Population Decline
Curve Shapes for Different Types
of Human Pressure

Taking a number of biological traits into account, such as life-history speed (e.g. generation time) and the carrying capacity of the environment, Di Fonzo, Collen and Mace (2013) simulated population size trends under a number of different types of human pressure. They looked at threats that are constant, increase or decrease in intensity as the population declines, and threats that act in proportion to the population size or that remain fixed as population size changes. They then statistically characterised the shape of the resulting curves using three different statistical models (linear, exponential, quadratic) and different curve shapes (concave or convex). This produced mixed results. Some types of pressure consistently produced the same type of decline curve regardless of the biological and environmental characteristics of the population, but others were more strongly influenced by generation length and habitat carrying capacity. This makes sense, since populations with a short generation time are likely to be better able to cope with and recover from human pressure. For most types of pressure, however, some tell-tale signs were usually identifiable. For example, pressures that are proportional to population size and increase over time tended to produce convex declines, whilst proportional pressure that decreases over time is more likely to produce a concave curve.

From Simulation to the Wild
That’s all very well and good, but how well does the simulated data match up to real-world wildlife populations? Using data from the Living Planet Index, the authors attempted to characterise the shape of real population declines and compared the model predictions with data about real human pressures impacting on these populations. Across 124 populations for 57 different species of mammal, they found that populations were most commonly experiencing concave declines, suggesting human pressures that are in proportion to population size, but decrease in intensity over time. There was some association between curve-shape and the actual sources of pressure, with exponential concave declines being associated with habitats suffering from exploitation, habitat loss, invasive species and pollution, and quadratic convex declines being more characteristic of disease-affected populations. However, most populations were subject to multiple human-pressures simultaneously, which may have partly obscured the relationship predicted by theory.

Population decline curves may not enable us to identify specifically which threats are affecting a population, however they can reveal important details of how those pressures are changing over time. The International Union for the Conservation of Nature (IUCN) Red list attempts to categorise species’ conservation status. Currently, the Red List includes population size decline when assessing conservation status, however this does not take into account whether those declines are accelerating or decelerating over time. Incorporating information about the shape of the decline curve can provide important insights for conservation – species experiencing accelerating declines may be prioritised when determining how to use limited funding. Population-level data can highlight the impact of human activities more rapidly than studying species-level information, as populations are likely to show more rapid responses to human change, and may act as an early warning of longer-term species decline.

The dynamics of real populations are complex, and species’ biological traits in combination with multiple human pressures acting on a population simultaneously can mean that reality does not always match perfectly with theory. However, studying the shape of population declines can reveal characteristics of the pressure being exerted on the population, may provide an early-warning system for species-level declines, and can be used to inform conservation priorities. This relatively simple method for assessing the type of decline a population is experiencing can provide valuable information to conservationists about which types of pressures are most influential, and how to act to prevent extinction.

Original Article:

() Ecology and Evolution

This project was made possible by funding from the Natural Environment Research Council (NERC)

Biological Traits Influence Vulnerability to Climate Change in Birds, Amphibians and Corals

Claire Asher25 June 2013

Climate change is fast becoming a reality, and with temperature rises of between 0.8°C and 2.6°C predicted over the next 35 years, biodiversity will certainly be impacted, with many species set to suffer declines or potential extinction. But all species are not equal and certain traits may make species more or less vulnerable to climate change than others. A new model presented in PLOS one this month investigates the impact of biological traits, such as physiology, ecology and evolutionary history, on vulnerability to climate change for some of the most threatened groups: birds, amphibians and corals. Around 10% of species are both highly vulnerable to climate change, and already listed as threatened with extinction. The model also identifies potentially vulnerable species for future conservation priorities, giving biologists a head-start in trying to slow the inevitable loss of biodiversity that climate change will bring.

Many researchers are interested in predicting how biodiversity might respond to climate change. Biodiversity is essential to human survival – diverse, functional ecosystems provide us with food, water and medicine. However, predicting how ecosystems might respond to changes in temperature and rainfall is a complicated matter. Most previous models have considered the availability of suitable habitat for species based upon their current range and predictions of temperature changes. However, not all species are created equal – biological traits of individual species are likely to play an important role in determining species survival. For example, some species are adapted to a very specialised habitat or are poor as dispersal and so may struggle to find alternative habitats even if they are available. Other species have long generation times and produce few young, or have very limited genetic diversity in the population, making adaptation to new habitats more difficult. Species like these are likely to be more vulnerable to climate change than generalists who are good at dispersal and produce lots of offspring. Not considering the biology of a species when modelling responses to climate change can lead to under- or over-estimations of how vulnerable a species actually is.

Accounting for Biology
To address this issue, Foden and colleagues, working in collaboration with Professor Georgina Mace from CBER, developed a systematic framework for assessing species vulnerability to climate change, and applied this model to three of the best-studied, and most endangered groups of animals: birds, amphibians and corals. They considered three factors – sensitivity (whether a species can survive where it is), exposure (the predicted extent of change under climate models), and adaptive capacity (whether a species can avoid the negative impacts of climate change by moving or evolving).

The components of species vulnerability - sensitivity, adaptive capacity and exposure

Components of species
vulnerability – sensitivity, adaptive
capacity and exposure

In consultation with extinction risk specialists, they identified 90 biological, ecological, phsyiolocial and environmental traits which are likely to influence vulnerability to climate change. In particular, they identified habitat specialisation, rarity, environmental tolerance, disruption of environmental triggers and interactions with other species as key components of species sensitivity to climate change. Adaptive capacity is composed of dispersal ability, barriers to dispersal, genetic diversity, generation length and reproductive output. They assessed these traits for each of 16,857 species of bird, amphibian and coral, across the globe.

The proportion of species in a region that are sensitive or have limited adaptive capacity (blue), high exposure to climate change (yellow) or both (maroon).

The proportion of species in a region that are sensitive or have limited adaptive capacity (blue), high exposure to climate change (yellow) or both (maroon).

Armed with these traits, they were able to determine sensitivity, adaptive capacity and exposure for each species, and generated maps of where species may be particularly vulnerable. They found that around 24% – 50% of bird species, 22% – 44% of amphibians and 15% – 32% of corals are both sensitive and exposed, and have limited capacity to adapt. They identified the Amazon region as containing many highly vulnerable birds and amphibians. Many bird species were also highly vulnerable in central Eurasia, the Congo basin, the Himalayas, Malaysia and Indonesia, with amphibians most vulnerable in north Africa, eastern Russia, and the northern Andes. The waters around Malaysia, Indonesia and the Philippines were hot-spots for highly vulnerable corals.

A Silver Lining
It’s not all doom and gloom, though. The study also identified some species and regions where species’ traits may make them more able to cope with climate change. Around 28% -53% of bird species, 23% – 59% of amphibians and 30% – 55% of corals may survive projected climate changes because of their inherent ability to disperse or adapt to change. In particular, southern Asia and North America may see less severe biodiversity declines than previously thought.

The interplay between climate change and biodiversity is complex, and unlikely to be uniform across taxonomic groups. It is important to consider the physiological, ecological and evolutionary traits of individual species when making predictions about the impact of climate change. This study considered the effects of temperature and rainfall changes, as well as ocean acidification and sea-level rise, on global biodiversity. However, many other factors will influence whether species survive over the long-term – habitat destruction, invasive species and pollution are also major drivers of extinction which need to be taken into account when predicting the future of a species. Taking into account the biology of a species, and it’s interaction with other species, is a major step forward in our understanding of how biodiversity will respond to the impending climate changes that are now inevitable.

Original Article:

This research was made possible by funding from the MacArthur Foundation.

Farewell to One of Darwin’s Frogs
…but it’s not too late for another

Claire Asher18 June 2013

Amphibian declines are one of the biggest conservation concerns of the 21st century. In a paper last week in PLOS ONE, Claudio Soto-Azat at the Universidad Andrés Bello in Chile, in collaboration with Ben Collen from GEE’s Centre for Biodiversity and Environmental Research (CBER), and colleagues at ZSL, reported some sad news about two species of Darwin’s frog in South American. They announce the exctintion of the Chile Darwin’s Frog and substantial declines in the closely related species, Darwin’s Frog.

Using published data and archived specimens, Soto-Azat and colleagues reconstructed the historical range of these two species across Chile and Argentina, and went looking for the frogs right across their original range. Not a single Chilea Darwin’s frog (Rhinoderma rufum) was found. They used modeling based upon recorded sightings to predict whether the Chile Darwin’s frog truly is extinct. Unfortunately, this model confirmed the worst, that Chile Darwin’s frog is now extinct in the wild, and probably vanished over 30 years ago.

Darwin’s Frog (Rhinoderma darwinii)
Image from ARKive. Photograph used with permission from (Universidad Andrés Bello)

Populations of the closely related Darwin’s frog (Rhinoderma darwinii) were found, however these populations are much smaller and more fragmented than previously thought. The authors recommend classifying Darwin’s only remaining frog as Endangered. No frogs were found in or near urban environments – the surviving populations exist in primary forest. The populations that have gone extinct had been put under strain from human pressures. In Chile, loss of native forest as it is chopped down to make way for pine plantations to satisfy a growing global demand for wood and paper may be reducing the availability of habitat for these colourful little frogs.

The same frog captured twice during the study - identifiable by it's unique underbelly patterning

Darwin’s Frog (Rhinoderma darwinii)
The same frog captured twice – identifiable by it’s unique underbelly patterning

Darwin’s frogs aren’t just colourful, they also have a rather remarkable way to care for their young. The male waits patiently until the eggs he fertilised are ready to hatch, when he swallows the eggs and holds them in his vocal sac as they hatch. The tadpoles remain their at least until they are able to feed by themselves, but in Darwin’s frog (R.darwinii), the young stay until they can hop out, as tiny froglets. Chile Darwin’s frog is lost forever, but it may not be too late to save Darwin’s frog, and this unusual strategy for rearing offspring.

Original Article:

() PLOS ONE