Lunch Hour Lectures on Tour – 10 May 2018

Richard Pearson,from University College London. Rich is a Reader in Biodiversityat UCL. He’s also the new Director of the Centre for Biodiversityand Environmental Research. Welcome to the worldof responsible grown-ups, Rich. His talk, flippancy aside,is really important. We all know that biodiversityaround the globe is declining. Rich’s talk is about answering thequestion of why we should care. Do we have some sortof moral responsibility to deal with this issue or should moreutilitarian values prevail? To give you a bit of backgroundabout Richard himself, I learnt he went to the same schoolas the Director of Science at NHM. A guy called Ian Owens. Some small town south of York,I believe. They’ve both been socialisedsince those times. You can be confident,so that’s a good sign. Rich did his PhD at Oxford before spending several yearsas a Post Doc at the American Museumof Natural History in New York. If you’ve never been there, I suggestif you find yourself in New York, that should be one of the placesyou go see, because it’s a truly amazing placeto visit and I imagine quite an interesting placeto work too.Rich’s work focuses on whereyou find animals and plants and why they’re there, how their distributionschange over time and what drives those changes. Also, as I started at the beginning,about why we should care about that. I’ve droned on enough. Ladies and gentlemen,Richard Pearson. Thank you, Ken. Let me dive straight in with this first slide, which is the tree of life. It’s one of these big trees,which shows the diversity of life. On the planet. I should emphasise, it’s looking atspecies-level diversity. When we talk about biodiversity, we tend to think not justabout species-level diversity, but diversity within species, genetic diversity, and diversity acrosswhole ecosystems as well. Communities of different species. I should emphasisethat you/we are here. Each of these grey bits of writingthat you can’t see the details of is a species. We are, of course,among the animals. We’ve got plants here,protists, bacteria, fungi, etc. This is what we meanby biodiversity. What I want to focus onfor the next half hour or so is our relationship.The relationship of this onerather peculiar animal with the rest of life on earth. A quick question for youto start with. How many of you like biodiversityand think we should conserve it? Not surprising.Everybody likes biodiversity. We all want to conserve it.It’s a no-brainer. You’re not necessarilya cross-section of the population. But, you ask a thousand people, and you get a thousandof the same answers. If I were to ask each of youa subtly different question, which would be why should weconserve biodiversity? Then we’d probably geta different set of answers. We’d get each of you coming upwith a set of different reasons that you would prioritisein different ways.If I were to go a step furtherand ask a more difficult question, that pits biodiversity conservation against other thingsyou’re probably in favour of, say, should we allow people to cut downtrees and hunt in a forest, that’s home to an endangered species,let’s say an endangered bird, but if the person hunting, their livelihood, their ability to feedtheir children depends on it, then we have a more difficultquestion to address. We’ve got to placewhat we favour about biodiversity against a whole suite of other thingsthat we’re interested in. The situation becomes less clearwhen we dig into it. I want to look a little bit deeper and have us think more aboutwhat are our reasons for conserving biodiversityand nature in general.I’m a conservation biologist. One of the areas I work inis the field of conservation biology, which we tend to refer toas a crisis discipline. I’m going to briefly outlinewhy that’s so. I want to try and send you awayin a few minutes time, at least cautiously optimistic. I’m going to suggest thatthis is a solvable problem. I’m also going to suggestthat in order to solve it, we really need to acknowledgethat it’s human interests that lie at the centreof why we should conserve biodiversity.There’s a lot of detail on here.I want to pick out the big picture. This is one way of looking at datafrom the IUCN, International Unionfor the Conservation of Nature. The red list, which I’m sure most of youwill have heard about. It’s a way of assessing whether speciesare threatened or not, based on a whole set of criteriaabout how the populations are declining, whether geographic rangesare declining or not. What we’ve got here,are the three best known groups, the birds, the mammalsand the amphibians.Each of these little symbolsrepresent 100 species. Of course, the ones in red are the oneswe consider to be threatened according to these criteriaof the red list. The proportions become fairly high. Maybe 13 or so % of birdsthat have been assessed, around a quarter of mammals, upwards of 40% of amphibians, we think are threatenedwith extinction over the coming decades. Overall, there are about 20,000 or sospecies of animals and plantsaround the world that are considered at high riskof extinction in the wild. We know from the fossil record thatmass extinction has previously occurred five times in the last540 million years. The last one occurredabout 65 million years ago. That’s what wiped outthe dinosaurs. This current rate of extinctionthat we’re seeing, puts us on coursefor a sixth mass extinction. This is something thatyou’ll see in the media and these are the headline numbersthat make us think that biodiversity is in crisis.Another way to look at this, this is data looking at populations nowrather than at species level, this is from the Living Planet report, that is published by WWF. A lot of the work behind that is doneat the Zoological Society of London, particularly throughthe Institute of Zoology. They work with the Living Planet Index. It’s based on about 14,000 populations that have been well studied, for over 3,500 vertebrate species. It’s a measure of average changein population abundance over time. What we see is this decline. If you pin the index at 1 in 1970, there’s been a declineof well over half. It’s about 58% up to 2012 inpopulation sizes for these vertebrates over those few decades.This is all background to say, this is why weas conservation biologists look at the numbers,look at the data. Our best understanding is thatwe have an issue here and this is why you’ll hear aboutsixth mass extinction and a biodiversity crisis. What are the causesof these biodiversity losses? What are the drivers? This is a very simple graph, showing it’s an aggregationof different indicators, that show what are happeningto the main threats to biodiversity. This is things like habitatfragmentation and deforestation, pollution, so nitrogen deposition. We all hear a lot about plasticsin the environment these days. Climate change.Over-exploitation. Fisheries in this picture. Invasive species,this is the brown tree snake, that invaded Guamover the last few decades and has caused a lot of damageto local biodiversity there. In general, what we see,is that the pressures are vastly increasing. This is what has led to another of thecatchphrases you’ll hear in the media of the Anthropocene. This is the idea of naminga new geological epoch. This is the age that is dominatedby human impact.The statistics around thisare things like half of all accessible fresh water onthe planet is used by humans. About 30 – 50%of the planet’s land surface is in some way exploited by humans. We see the pressures on biodiversitywithin the context of this broader ideaof the Anthropocene. The pressures are drivingthese biodiversity declines. That’s the classic storythat we’re faced with in this field. It’s often seen as a depressing oneand rightly so. Let’s be sure to place this withinthe context of human progress.This is something I thinkwe often talk about, the Anthropoceneas being quite negative. We view the pressures on the Earthas humans as the despoilers of the Earth without placing this in the contextof the phenomenal progress that we’ve seen in terms ofhuman wellbeing. These are data in termsof average life expectancy globally. Then split by different continents. Since the 1700s up to the present day, life expectancy across the planethas massively increased. Similar kinds of things in terms ofpercentage of the world’s population that’s in extreme poverty has plummeted over a similar time scale. We can plot similar things for deathsfrom infectious disease, malnutrition, literacy. Overall, we’ve got to placethe pressures on biodiversity within these composite measures that show that overall, human progresshas been positive by many measures.What we end up with is a bit of a divide between human progressand environmental degradation. Too often, we see this as a divide that pits human interestsagainst environmental. What I want to show todayand think through is that environmental protectionand human interests need not and cannot be seenas at odds with one another. This biodiversity crisis can bea solvable problem. We’ve made huge strides in all theseother measures of human wellbeing. We need to see the biodiversity crisisas another problem that we’ve got to solve. I want to argue that we want to solve itfor our own benefit. Over the next few minutes,I will explore why we value nature. What are the reasonsfor conserving biodiversity and which ones should be at theforefront of our ethics, our environmental philosophy, over the coming decades? Let’s take a narrative approachto start with and look at how human viewsof nature and conservation have changed over the last few decades.This is a narrative. It’s a very simplified narrative that my colleague at UCL, Georgina Mace,put forward. It gets us thinking. What you see, moving fromthe 60s and 70s to the present day, is these various framings. The first framing we think aboutis nature for itself. This is ideas of wildernessand protected areas. Think of Aldo Leopold’s land ethic. Wilderness not as for huntingand recreation, but as a place to be preserved for,what Aldo Leopold says, ‘the integrity, the stability, thebeauty of the biotic community.’ Another framing we would move onto would be nature despite people.This is threats to species. The things I’ve just talked about,habitat loss, pollution. Stemming in large part from work bypeople like Rachel Carson and her book on Silent Springthat was so influential. Leading into conceptssuch as Arne Nss’ Deep Ecology, which promotes the inherentor intrinsic value of nature and of biodiversityregardless of human use. What we’ve seen since the millennium, are influential reports such asthe Millennium Ecosystem Assessment and the TEEB, the study on the economicsof biodiversity and ecosystems, that focused on the benefitsthat humans gain from ecosystems.We have this other framing, which wetend to talk about as nature for people. This is when nature is providingservices for humans. I should just note on this slide,is what we’re not saying is that these have replaced each other. These are very much framings that existto the current day in parallel. That’s what Georgina was tryingto show in the bottom left as we’re looking at it here. These are different framingsthat exist today.This people and nature framing, benefits for natureand for people, is importantand dominant today. Here’s just one example, Michael Gove from the 25-year planto improve the environment in the UK, saying, ‘We need to respect nature’sintrinsic value, ‘the value of all lifeis critical to our mission. ‘But we also draw from the planetall the raw materials we need to live – ‘food, water, air and energy. ‘Protecting the environment,as this plan lays out, ‘is about more than justrespecting nature.’ This is people and nature, this is let’srespect nature for its intrinsic worth, but let’s also respect all the servicesthat we get from nature.This particular statement is wrapped upin the discussions about post-Brexitenvironmental policy and the proposals that farmers wouldreceive payments for public goods. You see similar dual framingsof why we should conserve nature in lots of different policy documentsaround the world. Just to summarise the different wayswe tend to value biodiversity. There’s a lot of disagreementover terminology. I’m simplifying a lot of sub-categoriesthat people will refer to. Essentially, we tend to refer toutilitarian value, the uses that humans derive from nature, or intrinsic value, this perceived value of natureirrespective of human interests.I want to spend a few minutes digginginto and critiquing each of these. For those of us based at UCL, this idea of utilitarian valueis very meaningful because utilitarianism was oneof the moral philosophies that was advocatedby Jeremy Bentham, who is often regarded asthe spiritual founder of UCL. Those that visit the South Cloistersat UCL will see his stuffed skeletonon display. If you visit right now, he’s actually ontour in New York, so you can’t see him over the summer,but he will be back. If you visit now, you won’t see hishead. His head was removed. The preservation of his head didn’t workwell, it’s rather gruesome. That’s not on display. Jeremy Bentham on displayin the South Cloisters, very much associated with UCL. Utilitarianism as a general ethic holds that the action is the onethat maximises utility. Utility is most often definedin terms of the wellbeing of people. I’m not going to get into the detailsof utilitarianism here. Any undergraduate philosophy textbookwill lay out the pros and cons.For our purposes, when we referto utilitarian value, in terms of biodiversity, we’re referring to the many usesthat we humans derive from biodiversity. That’s because biodiversity underpinsmany ecosystem services. Here’s a picture of a hoverflypollinating a flower. Some brief examples. There’s a lot written onecosystem services that are provided but things like pollination, wild pollinatorsare important for crops.Genetic diversity of wild cropsis important for improvement of crop strains. Of course, we get a lot of enjoyment and recreational valuefrom biodiversity. There are all these services. There’s all talks aboutwhat different services we get. I’ll include there indirect use values, which are anthropocentric,utilitarian, but they are things that we value eventhough there might not be a direct use. We gain satisfaction from knowingthat tigers, polar bears, gorillas continue to exist and they can bebequeathed to future generations maybe for future use, even though there is a direct use. We still gain value as humans from knowing that biodiversity exists and can be passed onto future generations.There are all these ecosystem services that we make use of. This idea of nature for peopleor utilitarian value is often associated with monetisation. Quantification of the benefitsthat we get. For example, it’s been estimatedthat pollination of crops globally, the global economic valueof crop pollination by animals is in the order of $200 billioneach year. We can, with great uncertainty,start putting economic values on biodiversity.The argumentsfor quantifying the benefits are basically along the lineof cost-benefit analysis. If we don’t quantify the benefits,they tend to be ignored, when we as a society are makingdifferent arguments for and against different land uses. They’re kind of consideredpublic goods. They’re available to everyonefor free. If we don’t put a value on them,they can be excluded. Essentially the true economic valueis ignored, if we don’t quantify it. That’s the utilitarian argumentfor trying to quantify the benefits. Let’s think a bit about intrinsic valueagain, which is this idea of value irrespective of the value to humans. To many people, this is real reasonwe should conserve biodiversity. This is the nature for itself viewpoint. Other species have a right to sharethe planet regardless of our uses. You might say it’s a moral imperative, in the same way we shouldn’t commitmurder or sell human organs, we morally shouldn’t be harmingbiodiversity. This kind of intrinsic value,nature for itself ideology tends to reject monetisation because putting a monetary valueon nature implies that it can be destroyedfor the right price.You’re putting a price on it,which means if you pay that price, you can destroy it. It’s summed up nicelyin this quote from the Guardian. It was part of a George Monbiotarticle from a few years ago. Can you put a price on the beautyof the natural world? Those who reduce natureto a column of figures, those who quantify the benefits, play to an agendathat ignores its inherent value. You can’t do this because you’re justputting nature up for a price.I think there’s a lot to be saidfor this argument. There is a huge risk in using free markets and quantificationof economic benefits to manage biodiversity. It might be inappropriate to put a monetary valueon the existence of tigers, but we need to be clear that doesn’tnecessarily mean that the economic value of pollinators shouldn’t be used to justifytheir quantification. Quantifying the value of something doesn’t necessarily mean we’re creatingan economic market for it. There are a lot of non-marketvaluation techniques that economists we work withare really on top of, that can be used to supportconservation. What I’m saying is we do need to beclever and cautious here in combining monetary valuationwith tight regulations that recognise intrinsic valueand the monetary value of ecosystems.We undoubtedly need to be waryof utilitarian value, economic valuation of biodiversity. Let me be a bit more criticaland give some reasons why I would argue the conceptof intrinsic value is inherently problematic. The first of those is thatit puts human wellbeing against the wellbeing of nature. It sets apart the interests of nature as separate from or conflictingwith the interests of humans. Think back to what I was talking abouta few minutes ago. We end up with this perception that nature conservationis at odds with human interests. Environmentalists value natureabove human needs. This is a bumper sticker, ‘Loggers arean endangered species too!’ This is from a few years ago, this long-running friction in thePacific Northwest of the US over the protectionof Northern Spotted Owls that were protected underthe endangered species act and kind of pittedthe local logging communities against environmentalists.The local loggers view was,quite understandably, that we were protecting owlsat the expense of their livelihoods. It was seen as pitting human interests against the interests ofthe intrinsic value of a particular owl because that species was endangered. We end up with another framing, this idea of people versus nature, that I think is antagonisticand isn’t going to help us to get at solving this biodiversitycrisis. Another thing to say is thatvalues are constructed by humans.Can values really be definedoutside human preferences? If the value isn’t to humansthen who or what is it to? Who is this intrinsic value to? One answer tends to beit’s to biodiversity itself. What does that actually mean? Do tigers or bees or earthwormssee value in their species in the same way that we seevalue in humans? Probably not. These are big, very difficult questionsto address when we pin the intrinsic valueof nature as being the most important reasonwe should value nature. If we’re going to define intrinsic valueoutside of human interest, the other approach is to infersome sort of higher being, which is why I have a pictureof the Pope from his Encyclical letterfrom 2015, which is very informativeon care for our common home. ‘Because of us, thousands of specieswill no longer give glory to God ‘by their very existence…We have no such right.’ The reason for conserving biodiversityin this framing of intrinsic value is because God or some equivalentsays it’s right not to do so.For the growing proportionof the planet’s population that take an enlightenedor non-religious viewpoint, for me as a scientist, that isa deeply unsatisfactory reason. This is why I come back to the idea ofbeing quite critical of intrinsic value. I think we need to favour a moreenlightened conservation ethic, enlightened in the sense that it doesn’trely on these superstitious ideas about morality being somethingaside from human interest. We need to acknowledge that it’s ourhuman interests that are at stake here. I’ve tried to dig a little bit. There’s a lot to be said and a lot ofarguing, I’m sure, about some of the concepts behindwhy we conserve biodiversity.I promised, having shown youbiodiversity is in crisis, to send you awaya little bit optimistic. Let me finish with a few reasons why Ithink this might be a solvable problem. Some of the context for thisis these sustainable development goals, which were adopted in 2015by the United Nations. They have a whole bunch of aimsrelated to reducing hunger, reducing poverty, providing education, gender equalityand the like. Some of them are quite specificallyof interest to us as biodiversity scientists. Target 15.5 for example, is to takeurgent and significant action to reduce the degradation of naturalhabitats, halt a loss of biodiversity and prevent the extinctionof threatened species. There’s been a lot of debateabout the STGs. Many people have questioned whetherthese big lofty ambitions or aspirations can really be turned intorealistic policies and results.In fact, an article in the Lancetdismissed the STGs in general as nothing more than fairy-tale. Let me finish by asking, is this idea of halting biodiversityloss a fairy-tale? Let’s look at some reasonsto be optimistic. Some key global trends that I thinkshould make us optimistic. A key underlying trend here that weusually think of is population growth. We’ve all seen, over our lifetimes,population growth. There’s been incredible growthover the past few centuries from about 1 billion humansin 1800 to more than 7 billion humans today.Our inclination is to expectrunaway population growth leading to environmentaland human catastrophe. This is Paul Ehrlich’s idea of apopulation bomb from a few years ago. The fact is, if you look at the numbers, this has been discussed a lot, the rate of population growthhas actually been falling. The rate of population growthhas been falling. The reason being that birth and deathrates have dropped as people and countries have becomewealthier and better educated. There’s now broad agreement amongdemographers, what you’re seeing on the right isscenarios of population growth over the coming century under different scenarios, calledshared socio-economic pathways, but there’s a general broad agreement that we’re probably looking atstabilising the world population around the year 2100 most likely around 8 – 10 billionpeople. It might be as low as 6,it might be as low as 12. This is important, because it meansthe planet doesn’t need to sustain an exponentially growingpopulation.There’s some reason to thinkthat the underlying factors here with a window of opportunity, could lead us to some stabilisedpopulation that we need to support alongside biodiversity. Other reasons for hope are essentiallythat we’re seeing accelerating responses to this biodiversity crisis. Firstly, there’s been real progressin the policy arena. For example, 184 out of 196 parties to theConvention on Biological Diversity, which is the big internationalconvention that countries are signed up tofor biodiversity conservation. The vast majority of those countries have developed national biodiversitystrategies and action plans. These are within-country strategies to set out actions such as promotinglaws and providing funds to help achieve the convention’s goals. There are other signs such asthe inter-governmental platform for biodiversity and ecosystem services, an IPCC for biodiversityand ecosystem services. There’s big international policy agendasto start addressing this. One way that that is turning intoat least some action, here’s a plot of protected areasin millions of kilometres since the 1920s for terrestrial in greenand marine in blue. What we see is that the amount of landacross the planet that is being protected is increasing.There’s big debates on how wellthose protected areas are functioning, but this is another good sign thatwe’re heading in the right direction. Another reason to be optimisticis a mainstreaming of biodiversity and this idea of natural capital, in business and economics. As I’ve argued, this is whatwe need to be thinking about in terms of quantifying the benefits. We’re really seeing this. For example, there’s the Natural CapitalCoalition, which involves manyof the really big players, Coca Cola, Deloitte, in business, in accountancy,in consulting, that are signed up to developinga case for valuing natural capital, ecosystems, biodiversity, in their accounting system. How the businesses are functioning. The financial industry as well. The UN has a set of principlesfor responsible investment, which commit investors.They sign up and commit to act inaccordance with conventions such as the conventionon biological diversity. These principles have around 1,400signatories who manage assets with a combined valueof about $59 trillion. These are issues that are increasinglybeing mainstreamed and there are some positive changes that have come to the forein the past few decades. Those policies, those actions, are resulting in some positiveconservation success stories. They illustrate how we canturn things around for biodiversity. Just to finish with a couple ofexamples, there are a lot of these. The EU Birds and Habitats directive have meant that there has beena real upsurge in large carnivores right across Europe. In many of the European regions. In areas that they have beenabsent for decades. The Iberian lynx is one such example. There are only about 52 matureindividuals in the wild in 2002. The populations have really beenbolstered over the last few years, the last decade or so. In the oceans, there is the exampleof the Guadeloupe fur seal, which twice in the past we thoughthad gone extinct, and it’s making a big comeback.More generally,there’s an overall positive trend. This is datafrom the Living Planet Index. I showed the overall trenda few minutes ago. It is negative, but across 1,000 birdsand mammals in Europe, in the Northern hemisphere at least, the trends are positive. There are positive trends.There are conservation success stories. Of course, there are onlyscattered examples at the moment. I’ve shown the overall trendsare declining, but there is increasing recognition within the area,I and colleagues work in that conservation is working and there are plenty of examplesto back that up. I’d say there is a general shiftfrom pessimism to optimism. For those of you who are more savvywith social media than I am, check out this hashtag, that’s beenpushed by the Smithsonian Institution and Cambridge Conservation Initiatives and others who are really reading this.Conservation scientists andpractitioners around the world are sharing conservation successstories. This isn’t a ‘Don’t worry, it will bealright’ kind of optimism. This is a ‘With a big effort, we cansolve this problem’ kind of optimism. What I’ve tried to argue today, is that we can solve this. We can be on track to solve this, but I think we need to acknowledgeit’s our own human interests that are at stakeif we’re going to turn things around. Let me finally acknowledge supportfrom the UCL Grand Challenges initiative which is one of the ways UCLis exploring solutions to some of these big societal questionsabout global health, about sustainable cities,justice and equality, cultural understandingand the like.I guess what I’m saying is thatconserving biodiversity is one of these big, grand challenges. Thank you very much. Thank you. The format is for the two talksto take place and then there will be questionsat the end. If you’ve gota burning question for Rich, don’t lose itwhile you listen to the next talk. The next talk,I need to read this out… Stephen Price is going totake us down a scale. He’s written an introductionfor his own talk, which wouldn’t do justiceif I didn’t read it out.Here it comes. Hollywood loves plagues that drivehumans to the brink of extinction, while governments fretabout disease threats to public healthand economic interests. Wildlife diseases receive less attentionbut are also of serious concern. In this lecture, you will learn abouta horrible viral disease, affecting frogs that livenear your homes. It is a case study thatwill give you insight into the most interestingand troubling aspects of infectious disease emergence. Devastation of host populations,weapons used to wage war and how the environmentand human behaviour can influence outcomes. Big stuff! Stephen Price. I really love this. He described his motivationsfor getting interested in zoology as Desmond Morrissey’s Naked Ape, and a spell cleaning up penguinscaught in an oil slick. [INAUDIBLE] I’m sure Stephen can explain a bit moreabout his science background and the work he’s been doingas a Post Doc and PhD student at QMUL and at ZSL and at UCL. [INAUDIBLE] Stephen, over to you. Ladies and gentlemen,Stephen Price. Thanks, Ken. It’s a real honour to be ableto present some of my research to you. Richard’s set my talk up,in one way, when he showed early on thatmore than 40% of amphibian species are threatened.I’m going to be talking todayabout one threat to amphibians, which is infectious disease. These are a couple of the main placesthat I share my work. Principally my website, which is2infectious.wordpress.com. If you’re interested in finding moreafter the talk, then I encourage you to go there and I’ll post a link to my slides, should you want to revisit anyof the material I present today. As Ken said, I’m a disease ecologist. I’ve been involved in research at ZSLfor almost nine years and have been working at UCLfor nearly five years. I said I was a disease ecologist. That’s because I’m interested inquestions, which focus on the ecologyand evolution of disease-causing agents or pathogens,and their hosts.Those are questions such as these. What makes a pathogenor a parasite bad? How do pathogens spread? How do pathogens that infect one host differ from those that can infect many? What other factors are going onaround disease events that affect the outcome? It also means that my workis quite varied. I spend some time out in the field, monitoring and samplingamphibian populations. I spend time in the lab, where I can be foundgrowing viruses or trying to isolate viral DNAfrom dead amphibians and then trying to decodethat DNA. Then I spend time in the officeat the computer analysing the data that I generate.Much of my research has focused onthis viral disease of amphibians, which is called ranavirus disease. This means it involves these two maincharacters, frogs and viruses. Although the disease can be horrible, I think it’s a fantastic systemto work on and I’ll spend the rest of my talk trying to ensure that you leavefeeling the same way. I’ll often talk about frogs, but I’ve also worked quite a loton these amazing characters, the salamanders, which include our beautiful UK newts. I think amphibians are a reallyfantastic species group to work on. They’re amazingly diverse in their colours, shapesand ways of life. They occur almost everywhere. They’re found on all continentsexcept Antarctica. On this map,the white regions are showing places where there were no amphibiansknown at the time.In contrast, red regionsare showing places where you have this phenomenalarray of amphibian diversity. As a direct consequence of this beauty,diversity and their global distribution. They are also animalsthat are accessible to humans. I’d like to do a quick straw poll. If you can, please all raise your hands. If you can remember a timein your life where you were doingsomething like this, collecting frog spawnor netting tadpoles, or just observing adult frogs, if you can keep your hands raised. If you don’t have such a memorythen you can lower your hands.Okay, fantastic. You can all put your hands down. There’s a sizeable majorityof people in this room who have fond memoriesof an interaction with amphibians. For me, it’s this that makes amphibianstruly unique organisms to work on. Wherever people live, even ifyou live in the largest city, there’s opportunity to go and witnessthis really remarkable natural event that is metamorphosis in amphibians. Through that, to connect very stronglywith the natural world. On the other side of my study system, it’s the viruses. It’s a bit harder for me to presentsuch a dazzling montage of wonderful images of viruses.That’s becausethey’re quite hard to see. They’re so very, very small. The next thing I want you to dois picture a single grain of salt on the end of your finger. I work on a group of virusescalled large DNA viruses on account of theirhuge size and the type of molecule thatencodes their genetic information. Nevertheless, in spite of this, you could fit 27 billion individualvirus particles into that single grain of salt that Iasked you to visualise. You can see that the large in the nameis really a relative term on account of their large size relativeto other viruses. They’re very small. Then, billions might also be the unit, if we think about the number of yearsviruses have been around on our planet. We know that viruses,almost certainly, the ancestors of some viruses go backto the very origins of life on Earth.Some think even earlier than that. They’re truly fascinating thingsto study. Now that I’ve given yousome background to the cast, I’ll get on with telling youmore of the science. My title is a big hint that I sometimes see this as a war between viruses and their hosts. Today, I’m going to show youthe nature of this war and how the impacts can bevery severe. I’ll demonstrate what is going onaround the interaction between a virus and its hostthat can influence the outcome. I’ll introduce you to some of theweaponry that’s used on both sidesof this battle. Finally, I’ll talk about howhuman behaviour can impact on wildlife disease. So, firstly I’m going to show youthe disease and I’m going to show you somephotographs you might find unpleasant.Just as a warning, it took me several years to get usedto seeing these types of images. I’ve come to realise they area really important element of understanding the impact of disease. Cue photos. Ranaviruses can cause a fatal disease. It can be quite gruesome. It’s typified by this systemichaemorrhaging, which means that animals can bleed fromalmost any or all of their organs. Sometimes you get this mind bogglingulceration. This is an animal that is still alivewith a big ulcer. You’ll also see this kind of extremelimb breakdown in some cases.Next we’ll look at the impactof this viral disease. We’ve known aboutranavirus disease in the UK for more than 25 years now. Most of what we know has come fromstudying garden ponds, where we know the diseasehas had a major impact. Back in 2008,a group of researchers from ZSL looked at ponds where the ownershad been observing disease outbreaks every year or twofor the previous decade.As a comparison, they looked at a set of ponds whereno disease had ever been seen. I’ll use these images throughout to show places where there is diseaseand places where there isn’t. In all cases, the pond ownersrecorded estimates of the frog population sizeat two time points, around 1996 and then again in 2008. Of course, no two ponds are the same in terms of their sizeor suitability for frogs, so there will be variation between pondsin the number of frogs you find there. This means that our data will fallin different places along these axes, which show the number of frogsat the two time points. In 1996 along the bottomand 2008 along the side. When we combine the datafrom a set of ponds, we can summarise it as a trend line. I’m showing here the 1:1 line,which is indicative of no change. No change in the number of frogsin a pond.If we’ve got 50 frogs in 1996, and then 50 frogs in 2008, you’re falling on this 1:1 lineshowing no change. 100 in 1996, 100 in 2008, again you’re on the 1:1 line. If our trend falls belowthis 1:1 line, it’s indicative there’s somethingbeen driving declines in these frog populations. If our trend falls abovethis 1:1 line, then the frog populationshave been growing in size. What was found was the green line here was the trend at siteswithout observations of viral disease. In the absence of disease, this is the trend that we seein frog population size over that decade.If we put the 1:1 line back forreference, then you can see that the trendis almost identical. There’s been nothing generally going on that’s been causing a changein frog populations. The red line is the trend at sites where there’s been repeated outbreaksof disease. You can see here that the patternis very different. We’ve got the 1:1 line in therefor reference. The shallowness of this linereally shows the impact of the viral diseaseon these frog populations. If you’ve got 100 frogs in 1996, then typically you were finding20 frogs by 2008. A really serious collapsein the frog numbers.What we’ve varied here betweenthe two sets of ponds, we’ve consistently varied the presenceof this viral disease. We can assume that it is the virus that has been causingthese collapses in frog numbers. I’m going to take you a bit farther awaynow to Spain. To the Picos de Europe National Park. This contrasts quite a bitwith the highly managed setting, where we were justin the garden ponds. This is a beautiful wilderness areain the north of Spain with high mountains, vultures,bears, and some fantastic flora.I’ve been lucky enoughto work here. Of course, the main reasonI’ve been going there is disease. It’s a place where we’ve been seeingmassive amphibian die-off. Here, I’ve blown up a map of the park. I’ve marked some of the places where we’ve been monitoringthe amphibian populations. In 2005, there was a big die-off of amphibiansat this site up here, marked Aliva. After that, my colleague,Jaime Bosch, implemented a programme of monitoringat many of the sites marked around the park. With the help of the rangers, there were annual countsof the number of amphibians. Soon after this initial outbreakin 2005, we started to see amphibians dyingat other sites. I’ve marked here this site, Lloroza, where all six of the amphibian speciesthat are common in this region are present at the site. All six have been involvedin these mass mortality events. I’m going to show you the massive impactof ranavirus in this region. We’ll just focus on one speciesinitially. It’s this toad,the common midwife toad, which is a wonderful toad, where the males carry the eggs aroundon their backs until they’re ready to hatch when theytake them and deposit them in the water.This graph shows counts of tadpolesover time at this pond, Lloroza, that I picked out previously. So, we’ve got the yearalong the bottom here. Then, the count of tadpolesof this common midwife toad along the side. We can see a really big change, starting from about 1500 tadpolesin the pond in 2007 and by 2010, there was almost notadpoles to be counted. If we contrast that with a site wherethere’s been no viral disease. This blue flat line going across summarises the trend in the numberof tadpoles at this site. What we see there is a very stablecount across the years. This pattern of collapse in the presenceof the viral disease and no change in the absenceof the viral disease, was replicated at other sitesin the park. We also saw the same patternin other species that we were able to monitorin the same way. The Alpine newt here,and the common toad. I’m sure you’ll agree that the impactsof this disease can be very severe.I’ve shown you this effectin two very different settings. Things are a little more complicatedthan I’ve shown you so far. I’ll demonstrate now how the environmentcan influence the interaction between a pathogenand its host. I’m going to use specific examples, the first of which is temperature. My research has benefited froma flagship citizen science project, known as the Frog Mortality Project. This project has collatedthousands of records of frogs dying over more than two decades. I’ve been using themto characterise what goes on around the time of disease outbreaks.If we look at how temperature affectsthe occurrence of disease outbreaks, we find that there’s a big differencebetween 10C and 20C. At 10C, there arefew disease incidents. We’re low down here. But at 20C, the rate of diseaseincidence is much higher. There’s a tipping pointaround 16C, where we movefrom few outbreaks to many. Not only that, but disease incidents tend to bemuch more severe, when the weather is warm.This graph includes incidenceof frog deaths from all causes. They’re grouped intodeaths by ranavirus disease, and deaths from any other factors. Ranavirus is shownwith the orange line. Then other factors shown in this otherline in blue. These boxes around the line justcapture some of the variation that we see in a large data set. What you can see is that regardlessof the cause of disease, as the temperature increasesalong the bottom there, the severity of these outbreaks, the proportion of animals in thepopulation that are dying gets worse. For the ranavirus, this orange line, the effect of temperatureis much bigger. We start off lower downthan the blue line. We end up higher. The gradient of the line shows there isa strong effect of temperature. We saw over here that when it’s cool, there are still some disease outbreaks.Now we’re finding that even when thosefew outbreaks are happening, the effect is nowhere nearas severe. A low proportion of the frogs in thepopulation are dying. What’s really great is we’ve been able to bringsome of these viruses into the lab and grow them in bottles. This has allowed us to test whetherthe patterns we see in the wild can be replicatedin this controlled setting. We can grow the viruses in bottles, there the infections happen normallyin fish cell lines, in our lab.We’re looking for this kind of thing. This is a lawn of cellsgrown on the bottle. These areas are placeswhere the cells have died, following infection with the virus and created clearingsin this cell lawn. So, when we vary temperaturein this controlled setting, temperature increasingalong the bottom here, and then viral growth measuredalong the side of this plot, we can see that virus growth increasewith increasing temperature. With this knowledge, we wondered howclimate change might affect disease. The prospects do not look great.By 2070, under a high emissions scenario, we can expect the territorythat is suitable for disease outbreaks to increase in both space and time. I’m showing this suitable territoryin red on these maps. You can see for May, where previouslyScotland and the north of England has been unsuitable territory based ontemperature, for these disease outbreaks, we’ll see severe disease outbreaks. By 2070, we see it startto become suitable. Then, we’re also seeing this increasein the disease season. Where we’ve previously seen no severeoutbreaks of disease in March and April, in the future we might expectwe will start to see disease there.This is important, because in the UK, we normally only see diseasein adult frogs, but we know from lab studiesthat tadpoles are susceptible. Our findings about the effects oftemperature suggest strongly that thisis purely a matter of timing. The young froglets have alreadymoved away from the pond by the time the environmental conditionsbecome suitable for disease outbreaks. If we’re starting to see the conditionsbecoming suitable in March and April, whenthe tadpoles are still in the pond, this might affectthe frog population’s ability to persist in the face of disease, by replacing adults thatare dying with tadpoles. It’s not all doom and gloom. We also found that the presence of lotsof shading around ponds reduced the severity of outbreaks. This uncovers an areafor future research. Maybe if the frogs have opportunitiesto regulate their temperatures through their behaviour, they will be better ableto tolerate infection.If so, this points to possible actionthat can be taken to mitigate the effects of disease. Another feature of the environmentthat can affect disease outcomes is contamination by pollutants. I’ve been involved in some researchwith a US lab, which has been looking at the chemicalpollutants generated by fracking to see how this affects diseasein tadpoles. We’ve seen that on their own,these chemicals, in the absence of any virus, these chemicals can be toxic totadpoles. This is showing survivalof amphibians through time. In the absence of chemicals,we expect all animals to survive. When you add increasing concentrationsof the chemical, the amphibians are dying. In the presence of the virusand the chemicals, we’re going to get deathsin all our treatment. Even in the absence of the chemicals, some of the tadpolesare starting to die. That’s this top line. There’s a significant effectof increasing chemical concentration on the survival of these tadpolesthat are fighting ranavirus infections.Down here, the amphibiansare doing much worse. This increased mortality is accompanied by higher levels of virusin the tissues. Here the animals experience the highestconcentrations of chemicals. They also havethe highest levels of virus. Here, we get a suggestionof why this might be. This plot shows an immune gene and how much is beingcalled on by the animal to fight infection. When we’ve got no fracking chemicals, the animals are calling onthis immune gene quite a lot.In the presence of even very lowconcentrations of the chemicals, there’s a lower use of this gene, which might be compromisingthe animal’s ability to fight infection. In the case of pollution, we saw that immunity might becompromised. This leads me on to my next topic,which is the weaponry used by both frogsand the ranaviruses to try and get the upper hand. For frogs, I’ve already shown thatan immune response can be important. We know that at leastsome amphibian species can mount sophisticatedimmune responses, involving specialised cellsand classical inflammatory responses. Amphibians also havemolecules in their skin, which act against microbes and some of these have been shownto inactive ranavirus. Then, we’re just starting to learnabout another response to infection. This one might be of interest to anyonewho’s used probiotic supplements. I’ve been working with ZSL colleagues who set up two typesof frog enclosure. The top one here is a simple enclosure.It’s clean, containing clean gravel,and water, with nothing allowed to decomposeinside the enclosure. The bottom oneis a more complex enclosure with dirt on the ground, leaf litter, and surplus fooddecomposing in the enclosure. Groups of frogs went intothe two types of enclosure and were maintained there for a while. Then, after a whilewe swabbed the frogs, which basically meanswe got a cotton wool bud and rubbed it across the skin to collect the bacteriathat were living on the skin. We can take this swab and extract theDNA from the bacteria and use the code in the DNA to work outthe names of the bacteria that were living on the frog. When we did this, we found the enclosure did indeed affectthe type of bacterial community that was living on the skin. In a simple enclosure, we got a less diverse bacterialcommunity on the frog skin. In the complex enclosure, a more complex bacterial community, made up of more species. What was not so intuitive was the effect that this differencein microbial community would have on survival in the faceof exposure to the virus.This plot summarises what we saw. Again, it’s a survival plot. Animals were challengedwith the virus. This continuous line shows how theanimals from the more complex enclosure with a more diverse microbial communityon their skin fared in response to the virus. The dashed line below shows the simplebacterial community on the skin. These animals survived less well. We went looking for these kindsof pattern in the wild. We revisited some of these pondswith a history of disease or disease free populations. We found thatin the disease-free populations, it was there that the frogs had the morediverse bacterial communities living on their skins. In the populations with disease, we had this significantly lowerdiversity in the bacterial community. When we looked atthe actual numbers of bacteria, it was flipped around. The animals from the diseased site hadmore individual bacteria on their skin than the animalsfrom the disease-free site..

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