Does nature have value beyond what it provides humans?

Michael Paul Nelson, Oregon State University; Jeremy T Bruskotter, Ohio State University, and John A Vucetich, Michigan Technology University

You can drive a nail with a hammer, and you can pull one. With a pencil you can write a poem or a song. Hammers and pencils are clearly useful – instrumentally valuable, that is. But if the pencil snaps or the hammer cracks, then it’s off to the trash heap.

Your daughter is different. She may be useful in mowing the lawn and providing a tax write-off, but she also possesses value far beyond her utility. Daughters are also intrinsically valuable.

What about the intrinsic value of nature? Does nature have only pencil- and hammer-like values, or does nature also possess intrinsic value?

A handful of very vocal conservationists these days make assertions about the exclusive importance of nature’s instrumental value. We will not be motivated to protect nature, they assert, unless we appreciate the full range of “ecosystems services” nature provides to humans (water purification, pollination and the like). In turn, they make claims about, even ridicule, the failure of appeals to conservation premised upon the intrinsic value of nature.

This fervent commitment to the instrumental value of nature even trickles down to individual, highly sentient, parts of nature. It’s okay to kill lions, they say, because killing a lion for a trophy can generate important conservation revenue. A lion’s life is, they say, instrumentally valuable, a means to an end.

All of these assertions are built upon the assumed truth of an empirical claim. They assume that only by appealing to the instrumental value of nature will we motivate environmental action, because, they assume, that’s how humans value nature. We are, that is, anthropocentric (from the Greek, meaning human-centered). Everyone knows that, right?

Actually, as it turns out, not right.

Widely held view

In our research we found that the premise currently underpinning so much conservation effort is wildly mistaken.

A survey we conducted with Ohio residents – hardly a bastion of tree-hugging-granola-munching-Birkenstock-wearing-Prius drivers – demonstrated that more than 82% of Ohioans acknowledged the intrinsic value of wildlife. A nationally representative survey of adults revealed very similar numbers (81%). Moreover, we see this high level of intrinsic value attribution across demographic groups: whether rural residents or urbanites, rich or poor, male or female, hunters or non-hunters. Interestingly, more than 90% of people who strongly identified as “conservationists” in the Ohio survey acknowledged nature’s intrinsic value. This suggests that conservationists who reject nature’s intrinsic value are out of the mainstream of their peers.

But if so very many of us believe in nature’s intrinsic value, then why do we seem to behave otherwise? Why do we continue to pollute more than necessary? Why do we continue to destroy natural habitats by expanding human developments in places where human well-being is already high? Why do we as a society make so many decisions that appear to be, or that actually are, inconsistent with the idea that nature possesses intrinsic value?

Perhaps because while you believe in nature’s intrinsic value, you don’t believe that enough of the rest of us share your belief for it to be an effective basis for conservation. Perhaps, that is, we’ve bought into a false narrative about our own ethical beliefs?


This is one of the many mistaken ideas about nature’s intrinsic value, but it’s an important one. The assumptions we make (rightly or wrongly) about the world, including about the way people value that world, control the approaches we take or believe to be viable, the questions we ask or fail to ask, and ultimately the outcomes we can expect or never even imagine. It’s vital that we get this right; it colors every aspect of our relationship with nature.

So, let’s give ourselves some credit, even a little pat on the back (but gently, only one hand, just for a moment). Now, let’s think hard about what widespread acknowledgment of nature’s intrinsic value means.

It means that we are not necessarily the equivalent of morally self-absorbed infants. We are more morally mature than we might have imagined, than people keep insisting.

But this is bittersweet, because with moral maturity comes moral responsibility. As we acknowledge that we attribute intrinsic value to nature, we must hold ourselves accountable for that acknowledgment.

We invite conservationists and the conservation community to engage in a moment of reflection: we say we believe nature has intrinsic value; from that belief, what follows?

The Conversation

Michael Paul Nelson, Professor of Environmental Ethics and Philosophy, Oregon State University; Jeremy T Bruskotter, Associate Professor of Environment and Natural Resources, Ohio State University, and John A Vucetich, Associate Professor of Forest Resources and Environmental Science, Michigan Technology University

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

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.

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.

How the zebra got its stripes: to ward off flies

Akshat Rathi, The Conversation and Angela White, The Conversation

Zebras’ stripes have baffled biologists since Charles Darwin. Many hypotheses have been proposed regarding their purpose but, despite hundreds of years of study, there remains disagreement.

In an attempt to end the debate, researchers have pitted various models against each other and systematically analysed data from past studies. Their results reveal the one reason zebras have stripes: to ward off flies.

A handful of ideas regarding zebras’ stripes have found some support among biologists. One proposed that the dark and light bands change how air flows around a zebra’s body and helps in heat management, which could go a long way in the hot tropical areas that zebras live in.

Another proposed the stripes were used by zebras as a way of social interaction. They may use them to identify other zebras and for bonding as a group in the wild.

A third proposal suggested zebras used the stripes as camouflage. While stripes are clearly visible in the day, there some thought that it helped at dawn, dusk, and in the night.

All these ideas were shot down when tested rigorously. Two others, however, remained intriguing.

Now, how do I get rid of these ants?
dkeats, CC BY

The first was that the stripes were used to dodge predators. It is called the “motion dazzle hypothesis”, and it suggests predators are confused by zebras’ stripes and cannot understand their movement. Research published in the journal Zoology in 2013 used a simulated visual system to show that zebra stripes do interfere with visual perception. But this is a difficult hypothesis to test in the field.

Martin Stevens at the University of Exeter has researched the motion dazzle hypothesis by getting human subjects to catch moving stripy objects on a computer. “It’s an artificial experimental system,” he admitted.

The second proposal was that stripes helped keep flies at bay. Zebras are especially susceptible to biting flies due to their geographic spread. These flies, which include the tsetse fly, stomoxys stable flies, and tabanid biting flies, are particularly prevalent in areas with high temperature and humidity – exactly the areas where zebras are normally found.

Bites from these flies can be nasty and, quite literally, draining. About thirty flies feeding for six hours on just one horse can draw as much as 100mL of blood. Usually the flies can number in the hundreds around one animal.

Zebras have shorter hair than other equids – the family that includes horses, donkeys and zebras – which may also increase their susceptibility to attack. Also, four diseases which are fatal to equids have been found in Africa. This could mean that investing in anti-biting defenses such as stripes is especially important for zebras compared to non-African equids.

It is possible that the dazzle effect acts on flies, rather than larger predators, and deter them from biting. “Stripes clearly have a number of functions,” Stevens said, “and these could be interacting in zebras.”

Revealing maps

In the new research, just published in Nature Communications, Tim Caro and his colleagues at the University of California in Davis, didn’t perform experiments. Instead they used ecological and observational data on zebras’ geographical locations and related factors. It is the first time that a comparative approach has been applied to find the reasons for zebras’ characteristic colouration. Caro thinks his findings may have nailed the answer at last.

Caro looked at seven species of equids and scored them for number and intensity of stripes. Just to be sure, they tested all five hypotheses regarding zebra stripes’ use: camouflage, predator avoidance, heat management, social interaction, and warding off flies. The extent of overlap between the geographic distribution of striped equids with each of these five measures was calculated.

E. greyvi, E. burchelli and E. zebra have stripes on all their bodies. Other equids don’t.
Caro, Izzo, Reiner, Walker and Stankowich

“The results were a shock to me,” said Caro. Of these five proposals, only warding off flies had statistical support. He had not expected such a clear-cut answer to the question. As the map shows, the only places where flies and equids live together are areas that are populated by striped equids.

The exact mechanism by which stripes deter flies remains unknown, but experimental studies performed by researchers at Lund University in 2012 have found support for this proposal. They created striped surfaces and stuck glue on them. Based on the number of flies on the surfaces with different thicknesses of stripes, they concluded that these flies stayed away from stripes as thin as those found on zebras.

“As is normal in science you get a solution that asks more questions,” Caro said. It is time to hand the problem over to vector biologists, who can understand the susceptibility of horses to biting flies.

In Darwin’s days, people didn’t consider animal colouration with respect to fitness advantages. “People thought that animal colouration existed simply to please humans or was caused directly by the environment,” Caro said.

Darwin “would be delighted” that researchers are now considering animal colouration as a functional trait, he said. We might not have all the answers regarding zebra stripes – but it seems we may be looking through the right lens.

The Conversation

Akshat Rathi, Science and Data Editor, The Conversation and Angela White, Commissioning Editor, The Conversation

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.

Five ways to stop the world’s wildlife vanishing

Paul Jepson, University of Oxford

Full marks to colleagues at the World Wildlife Fund and the Zoological Society of London for the Living Planet Report 2014 and its headline message which one hopes ought to shock the world out of its complacency: a 52% decline of wildlife populations in the past 40 years.

Over the summer I re-read Fairfield Osborne’s 1948 classic Our Plundered Planet – the first mass-readership environmental book that detailed the scale of the damage humanity wrought on nature. Faced with the figures in this report it is easy to slip into despondency and to blame others. But this would be a mistake. At the time, Osborne’s report must have been equally alarming, but the eclectic conservation movement of which he was part responded with confidence, hope and vision.

Their achievements were huge: the creation of a reserve network that forestalled the extinction of African creatures such as the elephant and rhino, the creation of a nature conservation agency, the International Union for Conservation of Nature) (IUCN) within the UN, and a raft of international wildlife agreements.

Today, conservation-minded people will probably be wondering what can be done to reverse wildlife declines. For me the question is how can today’s conservationists leave a wildlife legacy for the 21st century, and I think there are five ways we can change conservation to better fit the circumstances we face.

1. Decentralise and diversify

The effort to ensure that nature conservation became a policy area of the UN necessitated developing a strong international conservation regime. This has served us well, but the world has changed: centralised authority has given way to messy, networked governance organised across many levels.

If the Balinese want to restore Bali Starling populations in coconut plantations I say applaud their vision and learn from their innovation. What matters is that wildlife populations flourish, not that some institutionalised notion of a “wild species” gains global consensus. It is time to nurture diversity in conservation practice.

Bleak future?
Profberger, CC BY

2. View wildlife as an asset

Since the 1990s conservation has become overly technocratic, with nature framed as a natural resource and stock of capital available for human economic development. Given human self-interest this just leads to arguments over who gets what share.

I suggest a better way to frame environmental policy is in terms of natural assets – places, attributes and processes that while representing forms of value to invest in, are also at risk of being eroded and must be protected.

We’ve done this before – think of great national parks where wildlife conservation, natural beautification and outdoor recreation combine for the benefit of wildlife, while also emphasising regional or national identity, health and cultural and economic worth.

3. Embrace re-wilding

Re-wilding is gaining traction. I see re-wilding as an opening, an opportunity for creative thinking and action that will affect the future. A key theme is restoration of trophic levels – in which the missing large animals at the top of the food chain are reintroduced, allowing natural ecosystem processes to reassert themselves.

We might ask whether today’s reported declines in wildlife are a symptom of the ecosystem becoming more simple and, if so, whether re-wilding will lead to more abundant wildlife. Ecological intuition suggests the latter but in truth we don’t know.

The not-so-common grass snake
Thomas Brown, CC BY

In my view we need large-scale, publicly-financed re-wilding experiments to explore and develop new ways of rebuilding wildlife populations as an asset for society.

4. Harness new technologies

It’s clear that wildlife conservation is moving from being a data-poor to a data-rich science. The methods that underpin the Living Planet Report are state-of-the art, but even so we have yet to capture the analytical potential of “big data”.

Recent rapid developments in sensor technologies look set to bring about a step change in environmental research and monitoring. In ten year’s time, I predict that the challenge for indexing the planet will shift from searching out and compiling data sets to working out how to deal with an environmental “data deluge”.

Despite this, wildlife conservation lacks a coherent vision and strategy. There are plenty of interesting technological innovations, but they are fragmented and individualistic in nature. We need leadership and investment to better harness them.

The humble hedgehog.
Klaus Rebler, CC BY

5. Re-engage the powerful

Like it or not, the wildlife conservation movement was at its most influential – as a policy and cultural imperative – when it was filled with active members drawn from the political, aristocratic, business, scientific, artistic and bureaucratic elites.

This was between 1890 and 1970. Over the past 40 years conservation organisations have become more professional, building close working relations with bureaucrats, but approaching other elites simply as sources of patronage, funds and publicity. Conservation organisations must open-up, loosen their corporate structures and let leaders from other walks of life actively contribute their opinion, insight and influence to the cause.

But above all, keep caring

These are five starting points for discussion rather than prescriptions. Perhaps the greatest asset we have is the deep-rooted sense of concern for wildlife found across cultures, professions and classes. It’s time to open up the discussion, to put forward new ideas for debate, and to ask others to suggest new and novel ways to save wildlife.

The Conversation

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

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.

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.

No wonder we are so fascinated by chimps – they remind us of ourselves

Robert John Young, University of Salford

I can quite happily go to a zoo just to watch the chimpanzees. It is not that the other animals are boring, but that chimps are so fascinating. In recent days the media has reported their drinking of alcohol, their ability to vary smiles and a US move to designate them as endangered. So, what makes chimps so attractive to scientists and the general public alike?

From a scientific point of view they are our closest
genetic relative. We share more than 98% of the same DNA and had a common evolutionary ancestor only 5-7m years ago. So chimpanzee biology and behaviour can tell us much about ourselves. And of course chimps look like us (as do most primate species). Due to these similarities, chimps are one of the most studied primate species of all time.

Head scratcher
International Fund for Animal Welfare Animal Rescue/flickr, CC BY-NC

Chimps were first described approximately 300 years ago and ever since they have appeared in books, films, TV adverts and have even flown in space ships. Their importance in understanding human evolution cannot be denied and this further adds to their high profile within human societies. But during my childhood, chimps were portrayed on the TV as loveable clowns: just think of the Tarzan films or adverts for PG Tips.

However, in my opinion there is something else in the human condition that leads us to be infatuated with chimps. And it is not that they are the most cute and cuddly looking animal. That title goes to the giant panda. Instead it is to do with our human propensity to be voyeurs: we love to watch other people.

Interesting people are those who put on public display their loves, hates and passions. The problem is there is only so much staring and gawping that interesting people (celebrities aside) will tolerate. Chimps provide an alternative outlet for our fascination with others.

What’s the gossip?
Nataša Stuper/flickr, CC BY

Chimps are passionate, scheming, aggressive animals. In many ways they seem to represent the human condition in its most elemental state. When we observe them we are looking at ourselves. But they act without the restrictions that polite society puts on us. And in zoos on wildlife documentaries, groups that are used to being watched by humans are not shy about expressing their desires, be they sexual or otherwise. In other words they are a voyeur’s dream.

To watch a group of chimpanzees is to watch a soap opera unfold before your eyes, but without the pretence of time passing quickly. They live life in the fast lane. Just as one example, chimpanzees are 100 to 1,000 times more aggressive than humans. Even TV soap operas do not show this much action happening in short spaces of time.

Not-so human drama
Tambako The Jaguar/flickr, CC BY-ND

If a male chimp is angry with someone or something then he lets them know in no uncertain terms. This happens not just in terms of bashing things, but also through pronounced facial expressions such as bearing teeth. I think we humans are jealous of chimps because they can vent their aggressive feelings without societal disapproval.

A friend of mine use to work on a project observing captive giant pandas, the world’s most marketed animal. But despite their cuteness they were boring to watch, just eating bamboo, sleeping, defecating every half hour and mating once a year. I challenge anyone to spend a whole day observing them. They just have too little behavioural diversity, expressing interesting behaviours such as aggression or sex at very low frequencies.

Chimps also have a caring side. Once they have attacked and beaten another individual, they will soon go over and give them a hug to prevent this negative interaction spiralling out of control. They show empathy towards sick members of their group. Older individuals are tolerant of the capers of the younger individuals. They live in a loving society where individuals hold hands, hug and kiss in the manner of people from Latin countries. And their partiality to a spot of alcohol has now generated much excitement.

Even when chimps are sitting around doing nothing, as a human observer you sense that something interesting could happen at any second. They never seem to have vacant expressions even when they are resting. They appear to be scheming away, working out how to manipulate other members of their group for food, friendship or sex. Chimps give the impression of being intelligent without the need to be making and using tools to procure food – just sitting down will do.

Cuddle time
Carlos López Molina/flickr, CC BY-NC-ND

Finally, chimps display remarkably strong personalities. Just one day of watching a group in a zoo is enough for you to determine their characters. Some are bold, others timid. Some are very agitated, whereas others seem serene. It is this blend of personalities that creates interesting group dynamics and the script for their soap operatic lives.

We are addicted to chimps because they let us spy on their lives, lives that are so rich and amazing that one, whose name was Flo, even had her obituary published in the Sunday Times newspaper.

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.

Why animals’ pupils come in different shapes and sizes

Gordon Love, Durham University

Wolves and foxes are closely related and share many of the same characteristics. But look at their eyes – where wolves have rounded pupils like humans, foxes instead have a thin vertical line. But it isn’t just canines –across the animal kingdom, pupils come in all shapes and sizes. So why the differences?

It’s a question that has long interested scientists working on vision and optics. In a new study published in the journal Science Advances, colleagues from Durham, Berkeley and I explain why these pupil shapes have developed.

Goats, sheep, horses, domestic cats, and numerous other animals have pupils which vary from fully circular in faint light to narrow slits or rectangles in bright light. The established theory for this is that elongated pupils allow greater control of the amount of light entering the eye. For instance, a domestic cat can change its pupil area by a factor of 135 from fully dilated to fully constricted, whereas humans, with a round pupil, can only change area by a factor of 15. This is particularly useful for animals that are active both day and night, allowing for much better vision in low light conditions.

The cat on the right has got its night-vision goggles on.
Mark Sebastian (L); Kurt Bauschardt (R), CC BY-SA

However, if the only reason for elongated pupils was to control the amount of light entering the eye, the orientation would not be important: horizontal, vertical, or diagonal would all offer the same advantages. Instead, the pupils are almost always horizontal or vertical, which suggests there must be other benefits which explain this orientation.

Pupils fit for every niche

Our work has focused on the visual benefits of vertical and horizontal pupils in mammals and snakes. One of the most interesting factors we found is that the orientation of the pupil can be linked to an animal’s ecological niche. This has been described before, but we went one step further to quantify the relationship.

We found animals with vertically elongated pupils are very likely to be ambush predators which hide until they strike their prey from relatively close distance. They also tend to have eyes on the front of their heads. Foxes and domestic cats are clear examples of this. The difference between foxes and wolves is down to the fact wolves are not ambush predators – instead they hunt in packs, chasing down their prey.

In contrast, horizontally elongated pupils are nearly always found in grazing animals, which have eyes on the sides of their head. They are also very likely to be prey animals such as sheep and goats.

We produced a computer model of eyes which simulates how images appear with different pupil shapes, in order to explain how orientation could benefit different animals. This modelling showed that the vertically elongated pupils in ambush predators enhances their ability to judge distance accurately without having to move their head, which could give away their presence to potential prey.

Sheep can usually see you coming.
Sarah Nichols, CC BY-SA

Grazing animals have different problems to deal with. They need to check all around for prey and they need to flee rapidly in case of attack. Having eyes towards the side of their head helps them to see nearly all around them. Having a horizontal pupil enhances the amount of light they can receive in front of and behind them while reducing the amount of light from above and below. This allows them panoramic vision along the ground to help detect potential predators as early as possible. The horizontal pupil also enhances the image quality of horizontal planes and this enhanced view at ground level is also an advantage when running at speed to escape.

So, vertically elongated pupils help ambush predators capture their prey and horizontally elongated pupils help prey animals avoid their predators.

We realised our hypothesis predicted that shorter animals should have a greater benefit from vertical pupils than taller ones. So we rechecked the data on animals with frontal eyes and vertical pupils and found that 82% are what is considered “short” (which we defined as having a shoulder height of less than 42cm) compared with only 17% of animals with circular pupils.

We also realised that there is a potential problem with the theory for horizontal elongation. If horizontal pupils are such an advantage to grazing animals, what happens when they bend their head down to graze? Is the pupil no longer horizontally aligned with the ground?

We checked this by observing animals in both a zoo and on farms. We found that eyes of goats, deer, horses, and sheep rotate as they bend their head down to eat, keeping the pupil aligned with the ground. This remarkable eye movement, which is in opposite directions in the two eyes, is known as cyclovergence. Each eye in these animals rotates by 50 degrees, possibly more (we can only make the same movement by a few degrees).

Cyclovergence, explained.

There are still some unexplained pupils in nature. For example, mongooses have forward-facing eyes but horizontal pupils, geckos have huge circular pupils when dilated which reduce down to several discrete pinholes when constricted and cuttlefish have “W”-shaped pupils. Understanding all these variations is an interesting challenge for the future.

The Conversation

Gordon Love is Professor of Physics at Durham University.

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