What animals can teach us about stress

Aliza le Roux, University of the Free State

Humans, being essentially self-centred, want to know what makes them different from their wild relatives, as well as what similarities exist. But it’s not just a matter of curiosity. Other species can teach us a lot about the big issues that challenge us in modern society.

Stress is seen as a pervasive modern-day killer. It has an impact on everything from our intestinal processes to our cherished cognitive performance. But stress is not a modern thing. All animals stress about predators, hunger, and lack of sex. So, what can we learn from them?

If there were a sweet spot – the optimal stress level – at which most stressed animals show peak cognitive performance we could possibly use the information to modulate our own stress and mental feats. And it would be brilliant if we could develop a deep understanding of how wild animals perform under varying levels of risk, given that they have evolved to deal with these over millions of years.

Studying the link between stress and cognitive performance, however, is hampered by many challenges. Although our methods of measuring stress have improved dramatically in recent years, outside the lab it’s still very difficult to contrast chronic stress from, say, a long drought, versus acute stress, such as the presence of a predator. Or linking our measures of stress to wild animals’ learning and memory skills.

We’re only just scratching at the surface of this problem.

Not stressing the animals

The study of stress itself is coming into its own. Traditionally, researchers actually increased their study subjects’ stress levels by the collection of blood used to measure circulating stress hormone (cortisol) levels. More recently, though, we have been given a barrage of less invasive tools with which to measure animals’ anxiety.

Perhaps the most widely used technique is to extract hormonal data from fecal samples. There is no need to catch or handle the animal. By happy coincidence stressed animals produce even more poo than their calm counterparts. Fecal hormones have certainly confirmed many of our suspicions. Animals become more stressed when they are handled and in captive conditions like zoos. They also find losing a friend very stressful.

There have also been some surprise findings. It may seem obvious that being a subordinate animal is stressful, but research on baboons shows that alpha males may actually be the ones heading for a stomach ulcer.

Another way of indirectly assessing anxiety is by measuring changes in how much food wild animals leave behind in experimental feeding patches. The idea is that a relaxed animal will eat more of the food than an anxious individual, leaving behind more food. This is called the giving up density. Experiments such as these allow us to clearly see how wild animals perceive variation in risk in their natural landscapes.

We know from Giving Up Density experiments that Nubian ibex perceive increased tourism as risky, while samango monkeys use human observers as potential shields against predators, eating much more food when their human “guards” are nearby. These same monkeys also feel much more threatened near the ground, compared to positions higher up under the tree canopies.

An even more exciting recent development is the measure of stress through thermal imagery. Researchers are knee-deep in the development of reliable techniques using thermal cameras to detect rapid changes in body surface temperatures.

A spike in stress levels causes blood to shunt away from an animal’s body surface (may this be what gives us the chills when we panic?). Suddenly, and quite literally, the animal appears to be cooler. Armed with this knowledge, we may be able to monitor fluctuation in stress levels in real time.

With all of these tools at our disposal, you may imagine that we know everything there is to know about wild animals’ performance under pressure. Unfortunately we don’t.

There is still a lot to learn

Our knowledge of cognitive performance and stress is heavily skewed towards lab rats. A great deal has been learnt from them.

For example, experiments have shown some positive effects of stress on lab rats. Brief, acute stress can actually lead to an increase in neurons in rats’ brains. And rats who were stressed out as teenagers become more impulsive as adults, which can make them more effective foragers, especially under high risk conditions.

In some ways, these findings sound like great news. We can perhaps all relate to the idea that we perform rather well when the stressful situation is short-lived, but flunk out when the pressure is either non-existent or overwhelming. But what we can say about these very rodent-focused studies is that it’s time to move beyond rodents and beyond the lab.

Moving past rodents

Data are slowly trickling in.

Studies on wild animals appear to confirm the idea that long-term, chronic stressors can truly decrease your mental acuity. For example, a recent study on wild-caught guppies showed that those used to stress make a lot more mistakes in cognitive challenges compared to the relatively relaxed fish.

Left-handed marmosets, which are the target of more social attacks and are therefore perhaps more chronically stressed, also show negative cognitive biases compared to their right-handed group members.

Marmosets don’t function well cognitively in stressful situations.
Reuters

In my own lab we are trying to assess various ways in which varying risk can affect learning abilities. We are using Giving Up Density experiments to determine how well wild bat-eared foxes may perform in low-risk and high-risk situations.

The key to unlocking how animals deal with stress requires that we step off our pedestal and acknowledge that other animals may outdo us in some cognitive tasks. If we do this we may learn how to truly cope in our own rapidly changing landscape.

The Conversation

Aliza le Roux, Senior Lecturer , University of the Free State

This article was originally published on The Conversation. Read the original article.

Restore large carnivores to save struggling ecosystems

William Ripple, Oregon State University

We are losing our large carnivores. In ecosystems around the world, the decline of large predators such as lions, bears, dingoes, wolves, and otters is changing landscapes, from the tropics to the Arctic. Habitat loss, persecution by humans and loss of prey have combined to inflict great losses on these populations.

In fact more than 75% of the 31 largest carnivore species are declining, and 17 species now occupy less than half their former ranges. Southeast Asia, southern and East Africa, and the Amazon are among areas in which multiple large carnivore species are declining. And with only a few exceptions, large carnivores have already been exterminated from much of the developed world, including areas of Western Europe, and the eastern United States.

Top dogs keep ecosystems in order

Many of these large carnivore species are endangered and some are at risk of extinction, either in specific regions or entirely. Ironically, they are vanishing just as we are learning about their important ecological effects, which is what led us to write a new paper in the journal Science to document their role.

From a review of published reports, we singled out seven species that have been studied for their important ecological role and widespread effects, known as trophic cascades. These are the African lion, leopard, Eurasian lynx, cougar, gray wolf, sea otter and dingo.

Based on field research, my Oregon State University co-author Robert Beschta and I documented the impact of cougars and wolves on the regeneration of forest tree stands and riverside vegetation in Yellowstone and other national parks in western North America. Fewer predators, we found, lead to an increase in browsing animals such as deer and elk. More browsing disrupts vegetation, reduces birds and some mammals and changes other parts of the ecosystem. From the actions of the top predator, widespread impacts cascade down the food chain.

Similar effects were found in studies of Eurasian lynx, dingoes, lions and sea otters. For example in Europe, absence of lynx has been closely tied to the abundance of roe deer, red fox and hare. In Australia, the construction of a 3,400-mile dingo-proof fence has enabled scientists to study ecosystems with and without dingoes which are closely related to gray wolves. They found that dingoes control populations of herbivores and exotic red foxes. The suppression of these species by dingoes reduces predation pressure, benefiting plants and smaller native prey.

In some parts of Africa, the decrease of lions and leopards has coincided with a dramatic increase in olive baboons, which threaten crops and livestock. In the waters off southeast Alaska, a decline in sea otters through killer whale predation has led to a rise in sea urchins and loss of kelp beds.

Predators are integral, not expendable

We are now obtaining a deeper appreciation of the impact of large carnivores on ecosystems, a view that can be traced back to the work of landmark ecologist Aldo Leopold. The perception that predators are harmful and deplete fish and wildlife is outdated. Many scientists and wildlife managers now recognise the growing evidence of carnivores’ complex role in ecosystems, and their social and economic benefits. Leopold recognised these relationships, but his observations were ignored for decades after his death in 1948.

Top carnivores, at work keeping things in check.
Doug Smith

Human tolerance of these species is the major issue. Most would agree these animals have an intrinsic right to exist, but additionally they provide economic and ecological services that people value. Among the services documented in other studies are carbon sequestration, restoration of riverside ecosystems, biodiversity and disease control. For example, wolves may limit large herbivore populations, thus decreasing browsing on young trees that sequester carbon when they escape browsing and grow taller. Where large carnivore populations have been restored – such as wolves in Yellowstone or Eurasian lynx in Finland – ecosystems appear to be bouncing back.

I am impressed with how resilient the Yellowstone ecosystem is, and while ecosystem restoration isn’t happening quickly everywhere in this park, it has started. In some cases where vegetation loss has led to soil erosion, for example, full restoration may not be possible in the near term. What is certain is that ecosystems and the elements of them are highly interconnected. The work at Yellowstone and other places shows how species affect each another through different pathways. It’s humbling as a scientist to witness this interconnectedness of nature.

My co-authors and I have called for an international initiative to conserve large carnivores in co-existence with people. This effort could be modelled after a couple of other successful efforts including the Large Carnivore Initiative for Europe, a non-profit scientific group affiliated with the International Union for the Conservation of Nature, and the Global Tiger Initiative which involves all 13 of the tiger-range countries. With more tolerance by humans, we might be able to avoid extinctions. The world would be a scary place without these predators.

The Conversation

William Ripple, Professor and Director, Trophic Cascades Program, Oregon State University

This article was originally published on The Conversation. Read the original article.

Restoring and conserving nature in the Anthropocene means changing our idea of success

R. Keller Kopf; Max Finlayson, and Paul Humphries

The Earth has unofficially entered a new epoch – the Anthropocene. It suggests that humans are the dominant influence on the planet’s ecosystems and biosphere – the sum total of life and non-living material on Earth.

Many ecosystems have changed so radically that it is no longer possible to restore them to what they once were, and in other situations it is not appropriate. Instead we need to look at what we can change, accept the things we can’t, and recognise that humans are now an important part of nature.

Restore, reclaim, reintroduce?

Accepting humans as part of nature will require a shift away from traditional views of restoration and conservation.

Governments and communities worldwide spend enormous sums of money and countless hours of work on restoration projects, aiming to reverse the degradation that we have wrought over the past few centuries.

The United Nations, for example, has agreed to a target of restoring 150 million hectares of land by 2020, costing about US$18 billion each year.

In Australia, federal and state governments have several very large restoration programs targeting, in one case, the Murray-Darling Basin – to protect and restore the degraded flowing waters and wetlands of our most iconic river system – and, in another, the Great Barrier Reef – to maintain and restore the universal value of our most iconic marine ecosystem.

There is an elephant in the room

In most cases, restoration efforts aim to return ecosystems to a state closer to what they looked like in the past and how they functioned before modern society. This target is often termed an “historical baseline” .

Historical baselines are estimated from written, oral, photographic or other evidence of past conditions.

For example, restoration of an ecosystem to an historical baseline might involve removing an invasive species (such as carp) or reintroducing a locally extinct native species (such as bilbies). Historical baselines are inherently problematic, however, because estimates of what is “natural” depend on people’s perceptions, and ecosystems themselves change over time.

Environmental management often now seeks to rehabilitate, reclaim or remediate, all of which involve at best a partial move toward a past state.

The elephant in the room is that many – perhaps most – restoration projects fail to return ecosystems to a state that in any way resembles historical baselines. Governments in most countries still remain focused on management activities that are narrowly restricted to historical conditions (such as eradicating invasive species).

But management actions focused solely on historical conditions do not account for how ecosystems have changed and do not always represent the best course of action for maintaining biodiversity.

New baselines for a new world

In a new era, where anthropogenic pressures dominate, how do we set targets for restoration and conservation?

In many situations, contemporary ecosystems no longer resemble the historical condition, nor are they expected to.

In some cases, the historical condition has gone forever. For example, cities are here to stay and the Thylacine no longer exists. In others cases, the political will to reverse change (such as by removing large dams) does not exist, or else new species or conditions are now simply considered normal (for instance, trout in rivers or dingoes in the outback).

Without enormous technological advances, or alterations to the ways we manage our landscapes and natural resources, we may have to accept new types of ecosystems and their human-modified baselines.

We call these “Anthropocene baselines”. Anthropocene baselines are ecosystems or parts of biodiversity that cannot – or will not – be restored to historical conditions. They are usually caused by socio-economic and ecological (such as invasive species) constraints.

Defining these new baselines represents a shift away from using past conditions in the absence of modern society and provides a new point of reference for managing biodiversity in the Anthropocene. They recognise a reality of the modern world: humans depend on natural resources and, in many cases, biodiversity is depleted or permanently altered – but may still be used sustainably.

For example, the mouth of the Murray River has changed as a consequence of building barrages and draining inflows away from the Coorong. Connected systems are now isolated and species that were never part of the Murray mouth dominate this environment.

Given these massive changes, it is unreasonable to expect the contemporary ecosystem to respond to restoration efforts in the same way as it may have in the pre-European past.

But by delivering environmental water and minimising the effects of other human pressures, we may be able to achieve sustainability.

Should we just give up?

Anthropocene baselines do not mean we stop conserving or restoring ecosystems. Altered ecosystems have tremendous value to humans and wildlife, which must be maintained. Other environments, such as free-flowing rivers in wilderness areas, may function within historical baselines.

Anthropocene baselines should, therefore, never be used as targets for management when restoration or conservation to historical baselines is viable.

The Anthropocene acknowledges humans as part of the environment – if not the most influential part. We are therefore the problem and the solution.

Points of reference for managing nature must balance the unavoidable effects of humans, while ensuring these effects don’t cause further degradation.

This does not mean giving up, far from it. It means setting sustainable targets that include ourselves in a changing world. These new baselines will ultimately represent choices made by people. But these decisions should be guided by scientific evidence – focusing on the long-term sustainability, benefits and costs of different human activities.

The Conversation

R. Keller Kopf, Postdoctoral research fellow; Max Finlayson, Director, Institute for Land, Water and Society, and Paul Humphries, Senior lecturer in Ecology

This article was originally published on The Conversation. Read the original article.

Baboons don’t play follow the leader – they’re democratic travellers

Robert John Young, University of Salford

Baboons in the wild are known for their highly strategic and hierarchical societies. So when it comes to decisions about where to go, one might expect that some bolshie individuals will direct the group through its habitat. However, a new study of the collective movements of wild olive baboons in Kenya suggests that there are more democratic processes at play.

For wild animals location is everything. The decision to head north instead of south may lead you to a fruiting tree, a pool with water or a place of shelter: all of these things could be the difference between life and death. For that reason, animal movements are never random. Even when searching for things, animals will use specific patterns of movements to sweep their environment. Social animal species like monkeys may not sit down and have a confab over a map, but they still need to make a decision about where the group should be heading.

A baboon in sheep’s clothing?

Numerous theoretical studies show the more you use collective information, the better the decision making process turns out. So it actually makes sense for clever animals like baboons to ignore a dominant individual no matter how much of a despot they are, but instead use a democratic process.

Oliver might be resourceful but look at that silly stroll. He clearly has no idea where he’s going.
Andicat/wikipedia

So far, there has been a limited amount of knowledge about how baboons make decisions about movements. The problem is how to study simultaneous and collective decision making in animals that live in large groups. Baboons typically live in groups of around 100. High accuracy GPS devices mounted on the majority of group members is the answer: this will reveal how animals coordinate their movements relative to one another. I have used this technique in the past on a much smaller scale to investigate the secretive lives of mated pairs of maned wolves in Brazil.

The researchers monitoring baboons in Kenya did just this. When an animal moved off, its influence on the other members of the group was observed. Did the other members follow (that is, did it “pull” them along)? Or did the other members resist the initiative to move off (that is, “anchor” the group). And what happened when several individuals moved off at the same time in different directions?

The researchers found that there was no relationship between position in the hierarchy and pulling the crowd along. In other words, top baboons were as likely to be followers as being followed. This illustrates that leadership and social roles within a social group can be distinct roles. Just because you are the leader does not mean that everyone else in the group treats you like you are infallible in your decision making.

In general individuals were followed when they moved purposefully off in a set direction and were able to rapidly recruit or “pull” other individuals in that direction. This makes sense in that it suggests to other group members that the moving individual’s behaviour is goal driven, for example by looking for food. Perhaps the individual has suddenly remembered the location of a fruiting tree. It would therefore appear that baboons like to follow the crowd – this is similar to quorum sensing behaviour in bees and ants when they are choosing a new nest. The option with the most votes wins.

The 90-degree rule

A big problem of group movement is how to resolve disagreement about the direction to be taken. It is rather like being lost in a strange city on a night out with a group of friends with widely differing opinions about where to go. One effect of this for both humans and baboons is that it delays any decision being made as the conflict is being resolved.

So what’s the solution? It turns out that baboons have a special rule. When the difference between two individuals trying to initiate movements in different directions is less than 90 degrees from one another, then it is resolved by splitting the difference and taking a middle path. However, if the difference of opinion about directions is greater than 90 degrees then individuals accept the choice of one individual over the other. Initiators of movement in a certain direction build up followers, and the individual that has accumulated most followers will end up determining the group’s direction.

You are wrong – the difference is 91 degrees, not 88. Let’s follow Jack.
Rod Waddington/wikimedia, CC BY-SA

It is surprising that something as important as group movement in baboons can be determined by a few simple rules, which are based on the idea that it is better to use the group’s collective knowledge than trust in the opinion of their leader. And perhaps even more so the fact that a dominant individual accepts that it is better to be a sheep than a shepherd in certain situations.

The Conversation

Robert John Young is Professor of Wildlife Conservation at University of Salford

This article was originally published on The Conversation. Read the original article.

The riddle behind zebra stripes

Brenda Larison, University of California, Berkeley

How the zebra got its stripes might at first seem like an esoteric question. But it has fascinated many generations and is embedded in the lore of Africa. It is also a question that offers a great educational tool by helping the general public understand how evolution shapes the variation we see in nature.

I began studying the question out of pure curiosity. But could it be more? Could the answer to why zebras are striped provide any benefits to society? There are many ideas about the advantages that stripes might confer on zebras.

Three ideas have some support: that stripes help zebra escape predation, avoid biting flies, and keeping cool. I’ll take up each of these ideas in turn, while speculating about the societal benefits that could obtain if they were proven to be true.

Predation and the dazzle effect

The most well-known idea about why zebras are striped is that they help them escape predation. The thought is that the dazzle effect of their stripes confuses the predator about either distance, speed, direction of movement, or where one zebra ends and the other begins.

The dazzle effect has already been put to use. In the first world war, ships were painted with bold black and white patterns in the hopes of making them less vulnerable to attack.

Research is mixed as to whether stripes actually lend such an advantage to zebras or might instead make them easier to catch. Once we understand whether stripes make something harder or easier to capture, rest assured that technology will make use of the fact.

Stripes as insect repellent

It has also been suggested that zebra stripes keep disease-carrying flies, such as tsetses and horseflies, from biting. Nagana, a form of sleeping sickness carried by tsetse flies, is a serious deterrent to livestock rearing in parts of Africa. Much research has gone into trying to mitigate this problem.

Researchers are working on not only why zebras are striped, but how. By trying to work out the genetic basis, we might one day be able to breed zebra-striped livestock. I can just see a herd of zebra striped cows contentedly munching away in a swarm of confused tsetse flies.

This solution for livestock would be a double-edged sword, though. The inability to rear livestock is one reason some areas of Africa are safe from human encroachment and are left for wildlife.

At any rate, the waterbuck may have already stolen the zebra’s thunder. Researchers have discovered that waterbuck give off an odour that deters tsetse flies. Collars exuding this smell are now being developed for livestock to wear. This is very much like your dog or cat wearing a flea collar.

Stripes to stay cool

There is another idea about the function of zebra stripes that could have an impact on their survival, and could possibly benefit humans and the rest of the planet. Collaborators and I recently discovered that the strength of striping in one species of zebra, the widespread plains zebra, varies with temperature.

The more stripy zebra are found in hot, tropical climates. Preliminary experiments also suggest that strong black and white stripes may help keep zebras cool under the tropical sun.

Zebra stripes differ.
Brenda Larison

If the biting fly hypothesis is true, temperature may also influence how many parasites they carry. Clearly this matters for zebra in the face of climate change. Zebra in regions of Africa that have seasonally cooler temperatures have subtler striping and often lack stripes on the legs.

Should climate change render these regions hotter, these less stripy zebras may have insufficient ability to thermoregulate and they may be subject to bites by flies that now harbour more parasites. Either of these could pose serious problems for zebras if their populations cannot evolve stronger striping quickly enough.

On a more positive note, if zebra stripes can truly create cooling, imagine an inexpensive cooling system for buildings that requires no energy input once in place. Instead of turning on the air conditioning, just roll out a black and white striped cover onto your roof during hot spells. This could significantly reduce energy usage and help mitigate climate change.

Only time will tell whether any of these ideas pan out. Meanwhile, I work simply to satisfy my curiosity, and hopefully yours.

The Conversation

Brenda Larison is Assistant Adjunct Professor, Department of Ecology and Evolutionary Biology at University of California, Berkeley

This article was originally published on The Conversation. Read the original article.

Whips hurt horses – if my leg’s anything to go by

Paul McGreevy, University of Sydney

It’s not just the horses that wear blinkers during the Melbourne Cup, the so-called “race that stops a nation”, which takes place next Tuesday. Perhaps it’s the excitement, the champagne or the extraordinary speed of the race, but most Melbourne Cup Day punters appear blithely unaware that they are actually watching horses being whipped … and hard.

Last year more than 100,000 people attended the Melbourne Cup, with more than 3 million watching the race on TV in Australia alone. This would have to make whipping in horse-racing the most public form of violence to animals in Australia today, but most people don’t seem to notice it.

Some 75% of whip strikes hit the horse’s flank (side of the abdomen), in contravention of the International Agreement on Breeding, Racing and Wagering.
Liss Ralston

To be fair, it was only when I saw high-speed images of whip impact that showed visible indentation of the skin in 83% of impacts I appreciated how likely it was that routine whipping of horses in racing causes pain. As a veterinarian, riding instructor and horse behaviourist, I am ashamed to admit how late this revelation came to me.

That I had to see it to believe it made me consider the extraordinary impact of images in achieving positive change for animals over the centuries, and what modern-day imagery might achieve.

William Hogarth most graphically illustrates the whipping of tired horses in his 1751 engraving The Four Stages of Cruelty: Second Stage of Cruelty (pictured below).

In his Autobiographical Notes Hogarth says the images:

were done in the hopes of preventing in some degree that cruel treatment of poor Animals which makes the streets of London more disagreeable to the human mind …

William Hogarth’s Second Stage of Cruelty in which Tom Nero whips his horse in public.
Wikimedia Commons

Hogarth’s First Stage of Cruelty shows youths already comfortable in their abuse of animals such as dogs, cats and birds. As his series progresses, it becomes apparent society as a whole is either indifferent to or encourages cruelty, and that this augurs very badly.

Hogarth’s images nail the nexus between animal cruelty and human crime and violence, and are as relevant today as they were 263 years ago. Images of horses being whipped on the streets of Victorian England are recognised as a major impetus to the birth of the animal protection movement as we know it today.

These were exhausted work and carriage horses and observers could see they were being thrashed to deliver more effort, where none was possible.

Today horses are still whipped in public, but only in the name of sport. And while there are restrictions on the number of times the whip can be used during a race, the Sport of Kings removes these safeguards in the last 100m, when the horses are tired and unlikely to be able to give any more. As if this isn’t futile enough, there is no peer-reviewed evidence that shows using the whip at any time increases performance.

Indeed, in 2011, my laboratory used cutting-edge imaging technologies to demonstrate the futility of whipping, and was awarded a Eureka Voiceless Prize for this work.

The racing industry assures us that every whip used in racing must be padded and that “when used properly, the whip stimulates a horse and should not cause pain”. However, my analysis of high-speed videography shows that the padding fails to protect horses in 64% of strikes. It also shows that 70% of whip strikes are delivered “backhand”, so are not counted under rules limiting the number of strikes.

While there are plenty of international agreements on whip use, they seem to achieve little. One ruling embraced by more than 40 countries, including Australia, is that horses should not be struck on the flank (the side of the abdomen). When we studied more than 100 strikes with frame-by-frame analysis, we discovered that more than 75% were flank strikes. And yet, to my knowledge, no Australian jockey has ever been penalised for flouting this rule.

Liss Ralston

The use of animals in research in Australia, including to investigate whether whipping a horse hurts, requires compliance with rules adopted under animal welfare legislation. These include the proviso:

Pain and distress may be difficult to evaluate in animals. Unless there is evidence to the contrary, it must be assumed that procedures and conditions that would cause pain and distress in humans cause pain and distress in animals.

Given there is no evidence to show that whipping horses doesn’t hurt, I decided to find out whether having my leg struck with a racing whip, as hard as jockeys whip horses, would cause me pain and distress.

Well, the answer is a resounding “yes”, and the thermographic images I took clearly show heat at the site of impact. In the image below you can see white areas of inflammation in my upper leg 30 minutes after it was struck – only once. And a warning: this material is disturbing.

My view is that – because there is no evidence to the contrary – we must assume that, just as I felt pain and distress from the impact of the padded whip, similar whipping in a horse would also cause pain and distress.

Representatives from the racing industry will doubtless say horses have thick skin and are therefore immune to pain from whip impacts but there is actually no evidence of such pain resistance in horses. Indeed, horses can feel a fly on their skin such that it triggers a characteristic shake called the “panniculus reflex”.

As sports journalist Patrick Smith recently wrote:

if whips didn’t cause pain there would be no use to them.

Unfortunately, the Australian Racing Board has recently advised me that “it will not be participating” in a non-invasive study I proposed using the thermographic camera on horses before and after races to investigate exactly what changes whipping causes to horseflesh.

As a veterinarian and scientist, I believe that when such thermographic images become available, they will remove the public’s blinkers to reveal the unnecessary cruelty caused by whipping in horse racing, just as Hogarth’s engravings did for work and carriage horses.

Since 1888, the winning jockey at the Melbourne Cup has been presented with a golden whip. At the very least, isn’t it time to stop glorifying an instrument of, at best, discomfort and, at worst, pain? You bet it is.

The Conversation is currently running a series looking at the history and nature of violence.

Paul McGreevy is Professor of Animal Behaviour and Animal Welfare Science at University of Sydney.

This article was originally published on The Conversation.
Read the original article.

Rewilding isn’t about nostalgia – exciting new worlds are possible

Paul Jepson, University of Oxford

The restoration of natural ecosystems – “rewilding” – ought to be a chance to create inspiring new habitats. However the movement around it risks becoming trapped by its own reverence of the past; an overly nostalgic position that makes rewilding less realistic and harder to achieve.

The recent launch of Rewilding Britain is certainly exciting and timely. However George Monbiot’s vision of bringing back 15 iconic species falls short of the rewilding visions being discussed in universities.

These are emerging from advances in functional ecology and Earth system science. The vision of rewilding is more ambitious: it is about restoring ecological processes through reassembling the species that drive them. For example rooting by wild boars has repercussions throughout a woodland ecosystem. Such animals shouldn’t be reintroduced simply because they were once there, but because they could do something productive in future.

Don’t go native

Monbiot’s quest to restore “lost” species harks back to a past age. However many conservation scientists are more relaxed concerning the question of “nativenes”. They are willing to consider introducing non-native species if they contribute a functional role in ecosystems, and they view the past not as a benchmark to preserve or replicate but as an inspiration for ecosystem restoration.

For instance, “Monbiot’s 15” omits the auroch and tarpan which are classed as extinct. However in the 1980s progressive Dutch ecologists realised that their functional analogues survived as cattle and ponies and their ecological role could be restored through “de-domestication”.

They set about de-domesticating them at the famous Oostvaardersplassen reserve located a 40 minute drive from Amsterdam. This produced a “Serengeti-like” landscape: a type of nature unknown to Europe since humans settled down and started farming.

The auroch (or ‘heck cattle’) is king of the OVP.
Jan Nijendijk, CC BY-SA

The OVP, as it is known, made nature conservation political again and has become a landmark public experiment in ecology. I first visited it with a group of students in 2003 when we travelled to the Netherlands to meet the radical ecologist Frans Vera and engage with the controversies created by rewilding.

The OVP is created on reclaimed land and opponents argued that the fences and flood control created an artifical landscape that undermined any claims to its authenticity as a restored ecosystem. More seriously the policy of allowing the cattle and ponies to die of “natural” starvation enraged animal welfare and farmer groups who believed they should be subjected to the same welfare standards applied to animals in labs, farms and zoos.

The controversies surrounding the experiment, Vera’s hypothesis that Europe’s original vegetation was wood-pasture rather than high-forest, and other radical rewilding visions are inspiring a re-examination of the fundamental premise of nature conservation.

Rewilding’s big chance

I recently published a Rewilding agenda for Europe in the journal Ecography, as my contribution to the European Council’s “fitness check” of its nature legislation. The Birds and Habitats directives under review derive from the science and policy context of the 1970s. They are ageing. Both science and society have moved on.

Any revisions to European nature legislation should support the creation of experimental rewilding sites. Across the UK we could imagine the creation of wild cattle and pony step-lands on the Ridgeway, wild boar and deer-driven woodland ecosystems in Wales, and a Scottish arcadia of bison, moose, wolves and pine forest.

Wild boars in Wales?
vlod007, CC BY

We also need many more OVP-like public rewilding experiments close to urban areas. These would be contained sites that inspire and inform the public about scientific advances, and provoke us all to ask: what sort of nature do we want for the future?

Rewilding might offer fresh solutions to intractable conservation problems. For example, conservationists want to remove pine trees introduced to the Sefton Coast dune system near Liverpool but local residents love them for their scenic grandeur and red squirrels. The famous Formby footprints dating from 2,500 BC show that humans, wild cattle, deer and wolf once inhabited these coastal areas. Suggesting the reintroducing of wild cattle and companion herbivores and seeing what happens might prompt a unified vision for the dunes.

In practice rewilding is constrained by regulations on biohazards, public access and animal husbandry – and rigid and powerful 20th century conservation legislation and agencies which have no real incentive to innovate.

Conservation institutions need to modernise but no one wants to dismantle them and start over. We need designated spaces with regulatory flexibility – experimental rewilding sites – where we can plan future natures that will improve the quality of life for people and the planet.

Ordinary people are disenfranchised. Conservation policy is influenced by a coordinated lobby of a few big charities who have built their organisational models on the institutional structures of the late 20th century. George Monbiot’s vision catches the attention but advocates of rewilding need to develop realistic policy mechanisms to take their ideas forward. Rewilding experiments would give space for wider reflection and debate and give our conservation institutions time to adapt. Crucially they would reinvigorate conservation as a cultural force in the 21st century.

The Conversation

Paul Jepson is Course Director, MSc Biodiversity, Conservation and Management at University of Oxford.

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DNA evidence proves climate change killed off prehistoric megafauna

Chris Turney, UNSW Australia and Alan Cooper

Imagine a world populated by woolly mammoths, giant sloths and car-sized armadillos – 50,000 years ago more than 150 types of these mysterious large-bodied mammals roamed our planet. But by 10,000 years ago, two-thirds of them had disappeared.

Since the end of the 19th century, scientists have puzzled over where these “megafauna” went. In 1796, the famous French palaeontologist Georges Cuvier suggested a global catastrophe had wiped them out. Others were appalled. The great Thomas Jefferson was so against Cuvier’s idea he sent an expedition to try to find vast herds of these animals grazing contentedly in the American interior. The only thing anyone could say with certainty was there should be a lot more of them than we see today.

Alfred Wallace, who wrote the first paper on evolution by natural selection with Charles Darwin, noted that “we live in a zoologically impoverished world, from which all the hugest, and fiercest, and strangest forms have recently disappeared”. It’s one of the great historical whodunnits: what happened to the megafauna, and when did they disappear?

The two-tonne glyptodon survived until 10,000 years ago.
Pavel Riha, CC BY-SA

As with any good mystery, there are two main suspects: climate and humans.

The idea that our ancestors may have hunted the huge beasts to extinction has long been a popular view, particularly as the spread of humans around the world appears closely associated with their demise. Several major criticisms continue to be levelled at this theory, the most popular being that many large animals are still present in Africa, despite it having the longest record of occupation by people. Others in turn argue that humans co-evolved alongside megafauna in Africa for millions of years, giving animals time to learn from human behaviour.

The alternative is that a rapidly changing climate caused the habitat of the megafauna to shrink or disappear. As the planet warmed out of the last ice age 12,000 years ago, many animals would have struggled to adapt to the new environment. A major criticism here is that there have been other major climatic changes in the past, some of which have been equally extreme and rapid. What could have been so different with this most recent warming?

In a research paper published in the journal Science, we report new advances in ancient DNA, carbon dating and climate reconstruction that finally give some answers. Previously, as long as species appeared to survive in the fossil record the interpretation had been that nothing significant had happened for tens of millennia.

But thanks to ancient DNA analysis of megafaunal bones we now know that this approach has missed a series of events throughout the past 50,000 years when major parts of a species’ genetic diversity, or even the whole species itself, disappeared. Alongside this, more accurate carbon dating of the fossil remains shows these extinctions did not all happen at a single time but were staggered through time and space.

The authors recently discovered this DNA-filled mammoth vertebrae preserved in ice, while doing fieldwork in northern Canada.
Kieren Mitchell, Author provided

It’s important to realise the backdrop to these extinctions was a wildly fluctuating climate. The ice age of the northern hemisphere was not one long frigid wasteland. Instead, frozen conditions were punctuated by many short, rapid warming periods, known as interstadials, where temperatures would soar from 4 to 16˚C within just a few decades and last for hundreds to thousands of years. They represent some of the most profound climate changes detected in the recent geological past.

When we precisely compared the dates for European and American extinctions with climate records, we were amazed to find they coincided with the abrupt warming of the interstadials; in stark contrast there is a complete absence of extinctions at the height of the last ice age. As temperatures rose during the interstadials, dramatic shifts in global rainfall and vegetation patterns would have placed the megafauna under immense stress. Those that could not adapt to the rapidly changing conditions would have quickly succumbed. The European cave lion, for instance (Panthera leo spelaea in the chart below), survived through periods when much of the continent was covered in ice, only to go extinct during relatively benign conditions around 14,500 years ago.

Megafaunal extinctions mapped against climate change. Temperature history is shown along the bottom; the black and red bars represent 95% confidence ranges. Most animals went extinct during warm interstadial periods (shaded brown), and the last ice age (shaded blue) had almost no effect.
Cooper et al

There seems little doubt humans would have contributed to extinctions, however. While the dramatic climate shifts were the major driver in megafaunal extinction events, humans would have applied the coup de grâce to populations already suffering major stress.

In one likely scenario, humans would have concentrated their hunting efforts along dispersal routes, killing the few bold individuals moving out to re-establish an extinct population, causing localised extinctions to expand into larger and larger areas, that would have eventually led to an irreversible ecosystem collapse. It’s likely the scattered pattern of extinctions and the difficulty of detecting them from fossils alone is why the relationship with warming events has not been detected before.

So what does this mean for the future? Well for a start, rapidly increasing temperatures are not good news for the megafauna that survived the last warming. In many ways the rise of atmospheric CO2 levels and resulting warming effects are expected to have a similar rate of change to the onset of past interstadials, heralding another major phase of large mammal extinctions.

This seems all the more likely thanks to our “success” in developing the planet’s surface, breaking up areas of natural habitat and disrupting any connectivity that once existed between areas. Migration is becoming increasingly less of an option for species struggling to adapt to changing temperatures with little chance of back filling from neighbouring areas for re-establishing populations. Even after all these years, megafauna are providing a precious lesson from the past.

The Conversation

Chris Turney is Professor and ARC Laureate Fellow at UNSW Australia.
Alan Cooper is Director, Australian Centre for Ancient DNA at University of Adelaide.

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