Domains of Life

I am about to make you feel uncomfortable. Sorry, but there’s no way of avoiding it if I’m going to tell this story as it should be told.

You are a human being; a member of the species Homo sapiens sapiens, although the second “sapiens” was only put there because we like to feel we are important. Remember that. There used to be other species within the genus “Homo” but they died out, or were possibly killed off, most recently a few thousand years ago when Homo neanderthalensis finally succumbed to the insurgent sapiens somewhere on the Iberian Peninsula.

On a smaller scale, you are a collection of major and minor organs, bony structures, muscles, ligaments, tubular networks, soft tissues and various other organic materials; all structured in such a way that you are capable of living in a vast range of habitats and climatic zones, under tremendous pressure from all sorts of predators and invaders, from large animals to minute single-celled organisms. Through an extraordinary evolutionary process, your constituent parts have developed to fill an optimally agile and self-regulating body such that they are able to function in tune with each other, symbiotically and independently as required, while you get on with the business of being a conscious and self-aware individual.

Each of these constituent parts are constructed from billions of cellular structures of various types which, if not part of your body, would be considered organisms in their own right: fragile, yes, but only because they have evolved to become at least partially dependent upon the whole of which they are a tiny part. Within each of your cells are components called mitochondria, which convert the raw materials of proteins – amino acids –into energy, which the cell uses to fulfil whatever function it is required to as part of the multi-cellular thing that is your body. This may involve fighting off viral invaders, absorbing nutrients from food, expelling waste from blood, moving in time with muscular activity or firing off a message to a neighbouring cell to recall an image of something that happened in your past.

Each of these mitochondria are specially adapted bacteria, that once independently existed, but at some point were “hijacked” by or may have taken up residence in, an animal cell that would, from then on, benefit from the energy produced by the mitochondria – the same cells that constitute an infinitesimally small part of a component of an individual human being, among something like 6.8 billion other human beings on Earth. 6.8 billion human beings that are utterly dependent upon the rest of the massive food web of which they (we) are just a tiny part.

You eat fish? The chances are that if you live in the Industrial West, your fish was a carnivore that ate other fish. If you live in China or Indonesia, it is more likely that your dinner was vegetarian, missing out a few links in the chain, and retaining a lot more of the food energy that came from the algae, or phytoplankton, that ultimately derived its energy from sun by virtue of the photosynthetic process that uses solar energy to split carbon molecules off from oxygen molecules, and create carbon structures that constitute the building blocks of life.

But, of course, it’s not only the animals or plants you eat (and that they may eat or utilise in the form of soil and “waste” products) that you are dependent upon, but the crucial role each of these organisms plays in the various natural processes that take place on Earth: regulation of the climatic-oceanic system; soil formation; water purification and enrichment; nutrient distribution…in the world we live in today we would not survive without all of these processes operating at a high level of efficiency. Interfere with these processes at a local level, and ecosystems can collapse; damage these processes at a global scale, and the entire biosphere is forced to readjust. With humans at the very top of the food chain, and so dependent upon everything else, we will be some of the first casualties of any global extinction.

Try and balance a pencil on its tip.

The Psychosis Of Civilization

This beautiful continuum, of which we are such a physically insignificant part, takes some imagining. The numbers are mind-numbing – individual nematodes alone stretch into the quintillions, and bacteria are many orders more numerous – as is the complexity of the ecological nets that link together different animals, plants, fungi and the countless other organisms that actually constitute the great majority of all life on Earth. We sit as a delicate flower waiting to be blown away in the next breeze of extinction; yet what do we see as the most important factor in our role as human beings?

Money.

As I have discussed on The Earth Blog previously, our values have become outrageously skewed in favour of whatever benefits the onward march of the global economy. We do not see the rise and fall of habitat viability on the television news, instead we see the rise and fall of the markets in the capital economy; we do not count specie extinctions in newspaper bar charts, but we urgently count companies going bust; we do not map the catastrophic breaks in the energy flows between different parts of an ecosystem, but we do acknowledge every time a budget airline discontinues a route, or whenever a main road has “severe” delays. As if it matters.

The psychosis of Industrial Civilization is endemic: every person that places his or her trust in the system of hierarchies, politics, markets and mass consumption, undergoes a fundamental readjustment in priorities. No longer does the fate of our species rest upon our increasingly precipitous position within the global ecology; we can all hold hands, actually or virtually, and celebrate the majesty of the global economic miracle, safe in the knowledge that it will take us forward into a glittering future of jobs, money and all the other civilised things we have been taught to desire.

How we have become so determined to destroy the continuum of life in search of something so utterly trivial, has its roots in the history of civilization. Every civilization has had its own goals, but ultimately they have all come down to one thing: the insatiable desire to progress in whatever way is dictated by the elite members at the very top. Such “progress” takes many forms, but whether it be exploration, scientific discovery, technological prowess, imperial power or simply the idea of being “the best”, civilizations have to feel they are progressing in some way; and so its subjects – the civilians – become part of that collective desire. For what are we if we don’t keep progressing? Failures. From our fear of failure, others above us draw their strength – just at the moment we seem to be reaching the end, and as we stretch out our fingertips, another line is drawn even further away. So we note the new goals and conform to the wishes of the system; continuing to do as we are told.

Through this psychotic behaviour, civilizations thrive…until they fail.

What Is Really Important

When I wrote the chapter called “Why Does It Matter?” in my book, Time’s Up! I felt rather uneasy; as though I hadn’t managed to explain myself properly. The problem was that, beyond the physical argument for the continuation of our DNA that I offered, there was also a complex and deeply-philosophical explanation that I also had which didn’t translate well into words. It was like a version of the argument that Descartes gave for the existence of God; to paraphrase: “I have within me a perfect and unequivocal representation of God; how could that be so if there were no God.” It’s a terrible argument, but it demonstrates well how a very good idea – which Descartes no doubt thought was perfect at the time – completely fails to work when written down.

I’m going to have another go.

So, how do you feel about your place in the world? Do you feel small, insignificant, worthless, just a tiny part of something far greater than yourself? This natural feeling of inferiority when you realise you are just a tiny part of a greater whole is the reason why medieval religious leaders were so resolute about our exulted position in the Great Chain of Being, just below the angels, but above all other forms of life – so long as you accepted that monarchs, priests and landowners were considerably more perfect than the rest of us.

It’s the same in the industrial economy: there is this global system that has enormous, if transient, power over the whole of existence; that governs every aspect of the lives of the civilised, but you don’t have to feel small, so long as you are told how important it is to go to school, get a job, go to the shopping mall or buy something online, follow the latest fashions, and cast your vote. You are empowered by your participation in these activities. It’s just that some people are more empowered than others.

But why on Earth do you need to be told how important you are? It speaks volumes about our state of mind when in order to feel worthwhile we have to, for instance, achieve good grades at school. We are all human beings, for goodness sake! Even more than that, we are what we are: our consciousness is bound up in our physical being, and everything we know and feel – everything we will ever be – is determined by our personal interaction with what is around us. We are at the centre of our personal universe; not in any selfish way, but simply because we can never truly perceive anything outside of our point of view.

Thomas Nagel, the American philosopher, summed this up beautifully in his essay, “What Is It Like To Be A Bat?”:

After all, what would be left of what it was like to be a bat if one removed the viewpoint of the bat?
Substitute “human” for “bat” and it is obvious that human experience has to be a unique thing for humans and, by extension, for each individual human. That is why we are important; not because humans are essential to the global ecology or even because we are essential to the absurd construct we call Civilization, but because what matters, is what matters to us.

How could it be any other way?

Think about this for a short while and it becomes clear that the civilised world’s destruction of the natural environment cannot under any circumstances be acceptable, for it will endanger the one thing which matters above all else: ourselves.

Decision Time

You have to make a choice. Are you going to continue supporting and extending the global reign of Industrial Civilization; or are you going to once again learn to value yourself as the centre of your universe, and the thing that matters above all else?

To me that choice is remarkably easy, but you might take some persuading, not only because of the insidious hold that the civilised world has upon everything we do, but because you are possibly thinking that I have left something out – the other things that also matter dearly to you. Fear not; this is what I wrote in Time’s Up!

More than just our natural tendency to survive, though, is the manifestation of that survival instinct in the way we think. Consider the question: What would you risk your life to save? My initial instinct is to say ‘my family’, then ‘me’, then, with a little more thought, ‘the Earth in general’ and ‘my friends’. Remove the Earth from the equation and you have the kind of answer that most people give.

I have said that I was not entirely happy with the strength of reasoning I gave in the book, but with the addition of the philosophical argument to the obvious need to replicate our DNA – the survival imperative – then we can all be justified in wanting not only to protect ourselves, but also our families and those other people we really care about and need: the community.

In fact, all three typical responses are directly related to the natural instinct for survival. We instinctively want to protect our families in order to secure the continuation of our DNA through blood relatives and the people they depend upon to survive. We want to protect ourselves in order to protect our own DNA, and the opportunity for that to be further replicated. We want to protect our friends because they too are human beings, but not only that, we have consciously chosen our closest friends because of what they have in common with us – they are almost like family.

Community is the antithesis of civilization for civilization thrives on the division of humanity into tiny, atomised, competing parts; but community is the form in which humans have always survived best. The choice is simple now: Civilization or Community; Progress or Humanity; Death or Life.

This article is licensed under a Creative Commons Attribution-Noncommercial 3.0 Unported License.

Man-made carbon emissions “are affecting marine biological processes from genes to ecosystems over scales from rock pools to ocean basins, impacting ecosystem services and threatening human food security,” the study by Professor Mike Kingsford of the ARC Centre of Excellence for Coral Reef Studies and James Cook University and colleague Dr Andrew Brierley of St Andrews University, Scotland, warns.

Their review, published in the latest issue of the journal Current Biology, says that rates of physical change in the oceans are unprecedented in some cases, and change in ocean life is likely to be equally quick.

These include changes in the areas fish and other sea species can inhabit, invasions, extinctions and major shifts in marine ecosystems.

“In the past, the boundaries between geological ages are marked by sudden losses of species. We may now be entering a new age in which climate change and other human-caused factors such as fishing are the major threats for the oceans and their life,” Andrew and Mike say.

“Given how essential the oceans are to how our entire planet functions it is vital that we intervene before more tipping points are passed and the oceans go down the sort of spiral of decline we have seen in the world’s tropical forests and rangelands, for example.”

Man-made carbon emissions are now above the ‘worst case’ scenario envisioned by the Intergovernmental Panel on Climate Change (IPCC), causing the most rapid global warming seen since the peak of the last Ice Age. At the same time the carbon is acidifying the oceans, with harmful consequences for certain plankton and shellfish.

“At current emission rates it is possible we will pass the critical level of 450 parts per million CO2 in the atmosphere by 2040.  That’s the level when, it is generally agreed, global climate change may become catastrophic and irreversible,” they add. “At that point we can expect to see the loss of most of our coral reefs and the arctic seas.”

“The climate is currently warming faster than the worst case known from the fossil record, about 56 million years ago, when temperatures rose about 6 degrees over 1000 years. If emissions continue it is not unreasonable to expect … warming of 5.5 degrees by the end of this century.”

Scientists expect ocean oxygen levels to decline by about six per cent for every one degree increase in temperature and areas in the sea which are low in oxygen to grow by at least 50 per cent. This has major implications for the world’s most productive fishing waters in the cool temperate regions. The seas provide around one sixth of humanity’s protein food – and any loss in fisheries production will have a direct impact on us, he adds.

Besides the changes induced by carbon emissions, the oceans are also under assault from over-fishing, increased UV exposure, toxic pollution, alien species and disease. The combined effect is to weaken the ability of many species to withstand these multiple stresses.

Another risk is that warming will unlock vast reserves of frozen methane in the seabed, triggering uncontrollable, runaway global warming.

“In the face of such terrifying changes even large scale interventions such as establishment of very large networks of Marine Protected Areas are unlikely to be effective,” Mike cautions. “On a global scale, an immediate reduction in CO2 emissions is essential to minimize future human-induced climate change.”

The oceans can also play a role in the proposed solution of eliminating carbon emissions, by producing clean energy from wind, wave and tide – potentially – by triggering phytoplankton blooms with fertilisers to absorb more carbon from the atmosphere, or using the seabed to store CO2. However these require far more research to be sure.

“It may already be too late to avoid major irreversible changes to many marine ecosystems.  As history has shown us, these marine-based changes could have major earth-system consequences,” the scientists conclude.

Details: Andrew S. Brierley, and Michael J. Kingsford, Impacts of climate change on marine organisms and ecosystems, Current Biology 19, R602-R614, July 28, 2009

Reprinted from ARC Centre of Excellence: Coral Reef Studies.

The critical role of forests as massive “sinks” for absorbing greenhouse gases is “at risk of being lost entirely” to climate change-induced environmental stresses that threaten to damage and even decimate forests worldwide, according to a new report released today. The report will be formally presented at the next session of the United Nations Forum on Forests (UNFF) taking place 20 April-1 May 2009 at the UN Headquarters in New York City.

“Adaptation of Forests and People to Climate Change – A Global Assessment” was coordinated by the Vienna-based International Union of Forest Research Organizations (IUFRO) through the Collaborative Partnership on Forests (CPF), an alliance of 14 international organizations that each has substantial forestry programs.

Authored by 35 of the world’s top forestry scientists, it provides the first global assessment to date of the ability of forests to adapt to climate change and is expected to play a key role in next week’s UNFF discussions. The report presents the state of scientific knowledge regarding the current and projected future impacts of climate change on forests and people along with options for adaptation.

“We normally think of forests as putting the brakes on global warming, but in fact over the next few decades, damage induced by climate change could cause forests to release huge quantities of carbon and create a situation in which they do more to accelerate warming than to slow it down,” said Risto Seppälä, a professor at the Finnish Forest Research Institute (Metla) and Immediate Past President of IUFRO, who chaired the expert panel that produced the report.

Scientists hope the new assessment will inform international climate change negotiations, set to resume in December in Copenhagen, where forest-related deliberations thus far have focused mainly on carbon emissions from deforestation. The analysis shows that officials also must consider how the world’s forests are likely to suffer-and perhaps severely-as the earth gets warmer.

While deforestation is responsible for about 20 percent of greenhouse gases, overall, forests currently absorb more carbon than they emit. The trees and soils of the world’s forests are capturing and storing more than a quarter of the world’s carbon emissions. The problem, scientists say, is that this critical carbon-regulating service could be lost entirely if the earth heats up 2.5 degrees Celsius (4.5 degrees Fahrenheit) or more relative to pre-industrial levels, which is expected to occur if emissions are not substantially reduced.

The study notes that the higher temperatures-along with the prolonged droughts, more intense pest invasions, and other environmental stresses that could accompany climate change-would lead to considerable forest destruction and degradation. This could create a dangerous feedback loop in which damage to forests from climate change significantly increases global carbon emissions which then exacerbate the greenhouse effect.

The warning from scientists that forests are in danger of flipping from a net sink to a net source of carbon emerged from an exhaustive analysis of how different forest ecosystems worldwide would be affected under specific climate change scenarios developed by the Nobel-prize winning UN Intergovernmental Panel on Climate Change (IPCC). The authors of the report, some of whom also serve on the IPCC panel, noted that the impacts in different ecosystems would vary over time.

In fact, the authors found that the risk of losing forests as a net carbon sink is significant even in relatively conservative scenarios in which countries achieve modest emissions reductions and stabilize greenhouse gas concentrations. The loss becomes much more likely in scenarios where curbs fail to take effect and emissions continue on their current, upward trend.

“Policymakers should focus greater attention on helping forests and the people who live around them adapt to anticipated problems,” said Professor Seppälä. “For example, wider application of well-understood sustainable forestry practices, which offer a range of benefits, could help forests avoid some of the damage induced by climate change.”

Threats, But also Benefits, of Climate Change

The study observes that as climate change progresses over the next decades:

• Droughts are projected to become more intense and frequent in subtropical and southern temperate forests, especially in the western United States, northern China, southern Europe and the Mediterranean, subtropical Africa, Central America and Australia. “These droughts will also increase the prevalence of fire and predispose large areas of forest to pests and pathogens,” the study says.
• In some arid and semi-arid environments, such as the interior of the American west, forestry experts worry that climate change could be so dramatic that timber productivity could “decline to the extent that forests are no longer viable.”
• Decreased rainfall and more severe droughts are expected to be particularly stressful for forest-dependent people in Africa who look to forests for food, clean water and other basic needs. For them, the scientists predict climate change could mean “deepening poverty, deteriorating public health, and social conflict.”
• In certain areas, climate change could lead to substantial gains in the supply of timber. The combination of warming temperatures and the fertilizing effect of increased carbon in the atmosphere could fuel a northward expansion of what is known as the boreal forest, the coniferous timber lands that run across the earth’s northern latitudes and include forests in Canada, Finland, Russia and Sweden. Research from the report indicates that climate change could cause more than a 40 percent increase in timber growth in Finland. In fact, the study concludes that the increased growth in boreal forests could be large enough to spur a drop in timber prices worldwide. However, over the long-term, if climate change continues at the current pace the boreal expansion eventually will be offset by an increase in insect invasions, fires, and storms.

The scientists warn that efforts to adapt to climate change may end up providing forests with only a temporary respite.

“Even if adaptation measures are fully implemented, unmitigated climate change would, during the course of the current century, exceed the adaptive capacity of many forests,” said Professor Andreas Fischlin of the Swiss Federal Institute of Technology, who is one of the lead authors of the study and a coordinating lead author with the IPCC. “The fact remains that the only way to ensure that forests do not suffer unprecedented harm is to achieve large reductions in greenhouse gas emissions.”

Forestry experts acknowledge that more research is needed to better understand precisely how climate change will impact forests and how effective different adaptation responses will be. But they say the challenge to policy makers is that they must act even in the face of imperfect data because “climate change is progressing too quickly to postpone action.”

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About IUFRO and the CPF

The International Union of Forest Research Organizations (IUFRO) is the only world-wide organization devoted to forest research and related sciences. Its members are research institutions, universities, and individual scientists as well as decision-making authorities and other stakeholders with a focus on forests and trees.

For further information, please visit: http://www.iufro.org/.

The Collaborative Partnership on Forests (CPF) is a voluntary arrangement among 14 international organizations and secretariats with substantial programmes on forests. Its mission is to promote the management, conservation and sustainable development of all types of forest and strengthen long-term political commitment to this end. For further information, please visit: http://www.fao.org/forestry/cpf/en/.

Ecosystem services key to future conservation efforts, researchers say

The idea of ecosystem services is a promising conservation concept but has been rarely put into practice. In a special issue of the journal Frontiers in Ecology and the Environment, researchers use novel tools to report some of the first quantifiable results that place values on nature’s services to humans.

“The idea of ‘ecosystem services’ – identifying and quantifying the resources and processes that nature provides for people – gives us a framework to measure nature’s contribution to human well-being,” write authors Peter Kareiva, guest editor for this issue and the chief scientist at The Nature Conservancy, and Susan Ruffo, director of ecosystem services programs at TNC, in an editorial in the issue. “It provides a credible way to link nature and people that goes beyond emotional arguments and points us toward practical solutions.”

Some of the best-described ecosystem services include pollination of crops, flood and storm protection, water filtration and recreation. The challenging part is translating these services into something with a measurable value. Economic valuation methods take changes in the supply of ecosystem services and translate these into changes in human welfare.

“In this Special Issue of Frontiers, we have assembled pioneering examples of the quantification of ecosystem services and nascent steps toward turning that quantification into a framework for better land and water management,” Kareiva and Ruffo write.

The issue’s authors draw on current ecosystem services projects ranging from ranches in the Everglades to North American shorelines to cultural lands in Hawaii.

Novel programs such as the Florida Ranchlands Environmental Services Project (FRES) are designed to encourage the provisioning of ecosystem services from agricultural lands. These initiatives differ from traditional cost-sharing programs by paying landowners directly for the services their lands already provide, instead of giving incentives to adopt additional practices. In the Florida Everglades, agriculture has increased nutrient runoff into the Lake Okeechobee watershed since the 1940s, which has caused harmful algal blooms and ocean dead zones. State agencies are now developing a program to pay ranchers for ecosystem services produced by their lands, like water storage and filtration.

Another study shows that although wave attenuation, or the minimizing of ocean damage to shorelines by wetland habitats, provides quantifiable protection to coastal communities, this service can vary over time. Much like an economic market rises and falls with prosperous and hard times, these services vary over the winter and summer months, when shoreline plants are at different densities. The authors argue that most ecosystem services likely vary in a non-linear fashion, which will prove challenging for ecosystem modelers.

Placing a dollar amount on ecosystem services is not the only way to value them, however. In Hawaii, researchers say, ecosystem services evaluations should take into account cultural values, such as access to spiritual lands and areas available for gathering traditional plants used in ceremonies. The authors use a new software modeling program called InVEST (Integrated Evaluation of Ecosystem Services and Trade-offs) to help land managers and government workers assess this wide array of services.

The InVEST software has also shown that high levels of biodiversity often go hand-in-hand with the provision of more ecosystem services, suggesting that the preservation of biodiversity will enhance ecosystem services. This correlation is also reflected in the success of ecosystem service projects: The authors report that although conservation initiatives that focus on ecosystem services are still in their infancy, many are as successful as traditional biodiversity preservation approaches, and can often garner as much or more funding from the private sector.

“National governments around the world are taking note of ecosystem services,” the authors conclude. “The time is right for integrating the value of natural assets into decision-making.”

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The special issue was funded by The Nature Conservancy, the National Science Foundation and the U.S. Environmental Protection Agency.

The Ecological Society of America is the world’s largest professional organization of ecologists, representing 10,000 scientists in the United States and around the globe. Since its founding in 1915, ESA has promoted the responsible application of ecological principles to the solution of environmental problems through ESA reports, journals, research, and expert testimony to Congress. ESA publishes four journals and convenes an annual scientific conference. Visit the ESA website at http://www.esa.org.

Although it was a crucial part of humans’ survival 100,000 years ago, hunting is now nothing more than a violent form of recreation that the vast majority of hunters does not need for subsistence.(1) Hunting has contributed to the extinction of animal species all over the world, including the Tasmanian tiger and the great auk.(2,3)

Less than 5 percent of the U.S. population hunts, yet hunting is permitted in many wildlife refuges, national forests, state parks, and on other public lands.(4) Forty percent of hunters slaughter and maim millions of animals on public land every year, and by some estimates, poachers kill just as many animals illegally.(5,6)

Pain and Suffering
Many animals suffer prolonged, painful deaths when they are injured but not killed by hunters. A member of the Maine Bowhunters Alliance estimates that 50 percent of animals who are shot with crossbows are wounded but not killed.(7) A study of 80 radio-collared white-tailed deer found that of the 22 deer who had been shot with “traditional archery equipment,” 11 were wounded but not recovered by hunters.(8) Twenty percent of foxes who have been wounded by hunters are shot again; 10 percent manage to escape, but “starvation is a likely fate” for them, according to one veterinarian.(9) A South Dakota Department of Game, Fish, and Parks biologist estimates that more than 3 million wounded ducks go “unretrieved” every year.(10) A British study of deer hunting found that 11 percent of deer who’d been killed by hunters died only after being shot two or more times and that some wounded deer suffered for more than 15 minutes before dying.(11)

Hunting disrupts migration and hibernation patterns and destroys families. For animals like wolves, who mate for life and live in close-knit family units, hunting can devastate entire communities. The stress that hunted animals suffer-caused by fear and the inescapable loud noises and other commotion that hunters create-also severely compromises their normal eating habits, making it hard for them to store the fat and energy that they need in order to survive the winter.

Blood-Thirsty and Profit-Driven
To attract more hunters (and their money), federal and state agencies implement programs-often called “wildlife management” or “conservation” programs-that are designed to boost the number of “game” species. These programs help to ensure that there are plenty of animals for hunters to kill and, consequently, plenty of revenue from the sale of hunting licenses.

Duck hunters in Louisiana persuaded the state wildlife agency to direct $100,000 a year toward “reduced predator impact,” which involved trapping foxes and raccoons so that more duck eggs would hatch, giving hunters more birds to kill.(12) The Ohio Division of Wildlife teamed up with a hunter-organized society to push for clear-cutting (i.e., decimating large tracts of trees) in Wayne National Forest in order to “produce habitat needed by ruffed grouse.”(13)

In Alaska, the Department of Fish and Game is trying to increase the number of moose for hunters by “controlling” the wolf and bear populations. Grizzlies and black bears have been moved hundreds of miles away from their homes; two were shot by hunters within two weeks of their relocation, and others have simply returned to their homes.(14) Wolves have been slaughtered in order to “let the moose population rebound and provide a higher harvest for local hunters.”(15) In the early 1990s, a program designed to reduce the wolf population backfired when snares failed to kill victims quickly and photos of suffering wolves were seen by an outraged public.(16)

Nature Takes Care of Its Own
The delicate balance of ecosystems ensures their own survival-if they are left unaltered. Natural predators help maintain this balance by killing only the sickest and weakest individuals. Hunters, however, kill any animal whom they would like to hang over the fireplace-including large, healthy animals who are needed to keep the population strong. Elephant poaching is believed to have increased the number of tuskless animals in Africa, and in Canada, hunting has caused bighorn sheep’s horn size to fall by 25 percent in the last 40 years; Nature magazine reports that “the effect on the populations’ genetics is probably deeper.”(17)

Even when unusual natural occurrences cause overpopulation, natural processes work to stabilize the group. Starvation and disease can be tragic, but they are nature’s ways of ensuring that healthy, strong animals survive and maintain the strength level of the rest of their herd or group. Shooting an animal because he or she might starve or become sick is arbitrary and destructive.

“Sport” hunting not only jeopardizes nature’s balance, it also exacerbates other problems. For example, the transfer of captive-bred deer and elk between states for the purpose of hunting is believed to have contributed to the epidemic spread of chronic wasting disease (CWD). As a result, the U.S. Department of Agriculture (USDA) has given state wildlife agencies millions of dollars to “manage” deer and elk populations.(18) The fatal neurological illness that affects these animals has been likened to mad cow disease, and while the USDA and the Centers for Disease Control and Prevention claim that CWD has no relationship to any similar diseases that affect humans or farmed animals, the slaughter of deer and elk continues.(19,20)

Another problem with hunting involves the introduction of exotic “game” animals who, if they’re able to escape and thrive, pose a threat to native wildlife and established ecosystems. After a group of nonnative wild boars escaped from a private ranch and moved into the forests of Cambria County, Pa., the state of Pennsylvania drafted a bill prohibiting the importation of all exotic species of animals.(21)

Canned Cruelty
Most hunting occurs on private land, where laws that protect wildlife are often inapplicable or difficult to enforce. On private lands that are set up as for-profit hunting reserves or game ranches, hunters can pay to kill native and exotic species in “canned hunts.” These animals may be native to the area, raised elsewhere and brought in, or purchased from individuals who are trafficking in unwanted or surplus animals from zoos and circuses. They are hunted and killed for the sole purpose of providing hunters with a “trophy.”

Canned hunts are becoming big business-there are an estimated 1,000 game preserves in the U.S.(22) Ted Turner, who owns more land than any other landowner in the country, operates 20 ranches, where hunters pay thousands of dollars to kill bison, deer, African antelopes, and turkeys.(23)

Animals on canned-hunting ranches are often accustomed to humans and are usually unable to escape from the enclosures that they are confined to, which range in size from just a few yards to thousands of acres. Most of these ranches operate on a “no kill, no pay” policy, so it is in owners’ best interests to ensure that clients get what they came for. Owners do this by offering guides who are familiar with animals’ locations and habits, permitting the use of dogs, and supplying “feeding stations” that lure unsuspecting animals to food while hunters lie in wait.

Only a handful of states prohibit canned hunting, and there are no federal laws regulating the practice at this time.(24) Congress is considering an amendment to the Captive Exotic Animal Protection Act that would prohibit the transfer, transportation, or possession of exotic animals “for entertainment or the collection of a trophy.”(25)

‘Accidental’ Victims
Hunting “accidents” destroy property and injure or kill horses, cows, dogs, cats, hikers, and other hunters. In 2006, Vice President Dick Cheney famously shot a friend while hunting quail on a canned-hunting preserve.(26) According to the International Hunter Education Association, there are dozens of deaths and hundreds of injuries attributed to hunting in the United States every year-and that number only includes incidents involving humans.(27) It is an ongoing problem, and one warden explained that “hunters seem unfamiliar with their firearms and do not have enough respect for the damage they can do.”(28)

A Humane Alternative
There are 30 million deer in the U.S., and because hunting has been an ineffective method to “control” populations (one Pennsylvania hunter “manages” the population and attracts deer by clearing his 600-acre plot of wooded land and planting corn), some wildlife agencies are considering other management techniques.(29,30) Several recent studies suggest that sterilization is an effective, long-term solution to overpopulation. A method called TNR (trap, neuter, and return) has been tried on deer in Ithaca, N.Y., and an experimental birth-control vaccine is being used on female deer in Princeton, N.J.(31,32) One Georgia study of 1,500 white-tailed deer on Cumberland Island concluded that “if females are captured, marked, and counted, sterilization reduces herd size, even at relatively low annual sterilization rates.”(33)
What You Can Do
Before you support a “wildlife” or “conservation” group, ask about its position on hunting. Groups such as the National Wildlife Federation, the National Audubon Society, the Sierra Club, the Izaak Walton League, the Wilderness Society, and the World Wildlife Fund are pro-sport-hunting or, at the very least, they do not oppose it.

To combat hunting in your area, post “no hunting” signs on your land, join or form an anti-hunting organization, protest organized hunts, and spread deer repellent or human hair (from barber shops) near hunting areas. Call 1-800-448-NPCA to report poachers in national parks to the National Parks and Conservation Association. Educate others about hunting. Encourage your legislators to enact or enforce wildlife-protection laws, and insist that nonhunters be equally represented on the staffs of wildlife agencies.

References
1) National Research Council, “Science and the Endangered Species Act” (Washington, D.C.: National Academy Press, 1995) 21.
2) Grant Holloway, “Cloning to Revive Extinct Species,” CNN.com, 28 May 2002.
3) Canadian Museum of Nature, “Great Auk,” 2003.
4) U.S. Fish and Wildlife Service, “National Survey of Fishing, Hunting, and Wildlife-Associated Recreation” (Washington, D.C.: GPO, 2001) 5.
5) U.S. Fish and Wildlife Service 80.
6) Illinois Department of Natural Resources, “Poaching Is a Serious Crime,” May 2003.
7) Stephen S. Ditchkoff et al., “Wounding Rates of White-Tailed Deer With Traditional Archery Equipment,” Proceedings of the Annual Conference of the Southeastern Association of Fish and Wildlife Agencies (1998).
D.J. Renny, “Merits and Demerits of Different Methods of Culling British Wild Mammals: A Veterinary Surgeon’s Perspective,” Proceedings of a Symposium on the Welfare of British Wild Mammals (London: 2002).
9) Spencer Vaa, “Reducing Wounding Losses,” South Dakota Department of Game, Fish, and Parks, 2004.
10) E.L. Bradshaw and P. Bateson, “Welfare Implications of Culling Red Deer (Cervus Elaphus),” Animal Welfare 9 (2000): 3-24.
11) John Swinconeck, “Controlled Hunt May Be Solution to the Excess of ‘Deer at Our Doorstep,’” York County Coast Star 27 Jun. 2002.
12) Bob Marshall, “Is Predator Program Enough?” Times-Picayune 2 Mar. 2003.
13) Dave Golowenski, “Grouse Numbers Go Up if Trees Come Down,” The Columbus Dispatch 20 Feb. 2003.
14) “Hunters Shoot Two Relocated Bears,” Associated Press, 9 Jun. 2003.
15) Joel Gay, “McGrath Wolf Kills Fall Short,” Anchorage Daily News 25 Apr. 2003.
16) Joel Gay, “Governor Takes Heat From Hunters Expecting Aerial Wolf Control,” Anchorage Daily News 8 Apr. 2003.
17) John Whitfield, “Sheep Horns Downsized by Hunters’ Taste for Trophies,” Nature 426 (2003): 595.
18) U.S. Department of Agriculture, “USDA Makes $4 Million Available to State Wildlife Agencies for Strengthening Chronic Wasting Disease Management,” news release, 15 Apr. 2003.
19) U.S. Department of Agriculture, Animal and Plant Health Inspection Services, “Chronic Wasting Disease,” Nov. 2002.
20) Centers for Disease Control and Prevention, Division of Media Relations, “Fatal Degenerative Neurologic Illnesses in Men Who Participated in Wild Game Feasts-Wisconsin, 2002,” news release, Feb. 2003.
21) Judy Lin, “Pennsylvania Worried About Wild Boar Escape,” Associated Press, 17 Mar. 2002.
22) “Reps. Farr, Shays Introduce Bill to Can Canned Hunts,” U.S. Fed News 7 Oct. 2004.
23) Audrey Hudson, “Greens Cut Turner a Break; Critics Question His Stewardship of Western Land,” The Washington Times 20 Jan. 2002.
24) National Conference of State Legislatures, “Environment, Energy, and Transportation Program: Fishing, Hunting, and Wildlife,” Apr. 2003.
25) U.S. House of Representatives, H.R. 5242, Session 108, introduced 7 Oct. 2004.
26) Dana Bash, “Cheney Accidentally Shoots Fellow Hunter,” CNN.com, 12 Feb. 2006.
27) International Hunter Education Association, “Hunter Incident Clearinghouse,” 2006.
28) Tom Harelson, “1998 Deer Gun Season Report,” Wisconsin Department of Natural Resources, 8 Dec. 1998.
29) “Deer Eating Away at Forests, Nationwide,” Associated Press, 18 Jan. 2005.
30) Andrew C. Revkin, “States Seek to Restore Deer Balance,” The New York Times 29 Dec. 2002.
31) Roger Segelken, “Surgical Sterilization Snips Away at Deer Population,” Cornell News 19 Mar. 2003.
32) “Princeton’s Deer Hunt Coming to a Premature End,” Associated Press, 21 Mar. 2003.
33) James L. Boone and Richard G. Wiegert, “Modeling Deer Herd Management: Sterilization Is a Viable Option,” Ecological Modeling 72 (1994): 175-86.

In some parts of the tropics, frogs are the most abundant land vertebrates. This peculiar-looking casque-headed tree frog is one of the estimated hundreds of species of tropical frogs.

Such catastrophic declines have been documented for more than a decade, but until recently scientists knew little about how the loss of frogs alters the larger ecosystem. A University of Georgia study that is the first to comprehensively examine an ecosystem before and after an amphibian population decline has found that tadpoles play a key role keeping the algae at the base of the food chain productive.

“Many things that live in the stream depend on algae as a base food resource,” said lead author Scott Connelly, a doctoral student who will graduate in December from the UGA Odum School of Ecology. “And we found that the system was more productive when the tadpoles were there.”

The results, which appear in the early online edition of the journal Ecosystems, demonstrate how the grazing activities of tadpoles help keep a stream healthy. The researchers found that while the amount of algae in the stream was more than 250 percent greater after the amphibian population decline, the algae were less productive at turning sunlight and nutrients into food for other members of the ecosystem. Without tadpoles swimming along the streambed and stirring up the bottom, the amount of sediment in the stream increased by nearly 150 percent, blocking out sunlight that algae need to grow.

The study is part of a larger effort known as the Tropical Amphibian Declines in Streams (TADS) project, which also involves researchers from Southern Illinois University, Drexel University and the University of Alabama. The project is now in its third round of funding by the National Science Foundation and was initiated by Catherine Pringle (UGA Odum School of Ecology) and Karen Lips (Southern Illinois University) in 2000 through a Small Grant for Exploratory Research (SGER) from the NSF. Connelly and Pringle are monitoring in-stream effects of the population decline on algae, while other team members are studying how the loss of frogs impacts other organisms and the transfer of energy between streams and the terrestrial communities that surround them. Preliminary data show that the number of snakes that feed on frogs, for example, has plummeted after the population decline.

“We were there before, during and after the extinction event and were able to look at the ecosystem and measure how it changed,” said Pringle, Distinguished Research Professor in the Odum School and study co-author. “Very rarely have scientists been able to do that with respect to any organism.”

The chytrid fungus responsible for declines has steadily marched southeast across Costa Rica and through much of Panama like a storm front, killing up to 90 percent of frogs in afflicted streams. In 2003, the team set up research sites on two streams in the pristine and lush highlands of Panama. One study site had already suffered a catastrophic amphibian decline, while the other had a healthy population but, based on its location, was directly in the path of the fungal disease.

University of Georgia doctoral student Scott Connelly trekked to remote and pristine streams in Panama to study the impact of the chytrid fungus on frogs and stream ecosystems.

In the first stage of their research, Connelly and Pringle assessed ecosystem changes that occur when tadpoles are experimentally excluded from small areas of both the healthy stream and the frogless stream. They found that the absence of the tadpoles resulted in more sediment and less productive algae.

In late 2004, frogs in the formerly healthy stream began dying. The team reassessed the stream and found that impact of the frog die-off was even greater than they had predicted in their exclusion studies. “We predicted the direction of the change,” Pringle said, “but underestimated its magnitude.”

The UGA research team is continuing to monitor the health of the streams to get valuable, long-term data. So far the stream has not rebounded. “It’s still sad going back,” Connelly said, to which Pringle added: “Once the frogs die, it’s like an incredible silence descends over the whole area. It’s eerie.”

To date, scientists have not found a way to stop the spread of the fungus in the wild. Broadly applying a fungicide to an entire watershed, Connelly said, would kill beneficial fungi that are necessary for a healthy ecosystem.

But scientists can cure individual frogs in captivity by simply swabbing them with a fungicide. Connelly has worked to protect frogs through Amphibian Ark, a global effort supported by zoos, botanical gardens, aquariums and research institutions that aims to ensure the survival of amphibians by collecting and breeding them. The Atlanta Botanical Garden is one of the key breeding sites.

“The one speck of hope is that if we’re able to collect some of these rare animals, we can cure them,” Connelly said. “As long as we have the money to keep a breeding program going, in the future it might be possible to reintroduce them into the wild.”

Photos by Scott Connelly/UGA

Reprinted from the University of Georgia.

Meanwhile, a related discussion has ensued among international-security experts who believe climate-change-related damage to global ecosystems and the resulting competition for natural resources may increasingly serve as triggers for wars and other conflicts in the future.

Jürgen Scheffran, a research scientist in the Program in Arms Control, Disarmament and International Security and the Center for Advanced BioEnergy Research at the University of Illinois, is among those raising concerns. In a survey of recent research published earlier this summer in the Bulletin of the Atomic Scientists, Scheffran concluded that “the impact of climate change on human and global security could extend far beyond the limited scope the world has seen thus far.”

Scheffran’s review included a critical analysis of four trends identified in a report by the German Advisory Council on Global Change as among those most possibly destabilizing populations and governments: degradation of freshwater resources, food insecurity, natural disasters and environmental migration.

He also cited last year’s report by a working group of the Intergovernmental Panel on Climate Change indicating that climate change would affect species and ecosystems worldwide, from rainforests to coral reefs.

In his analysis, Scheffran noted that the number of world regions vulnerable to drought was expected to rise.

Water supplies stored in glaciers and snow cover in major mountain ranges such as the Andes and Himalayas also are expected to decrease, he said.

“Most critical for human survival are water and food, which are sensitive to changing climatic conditions,” Scheffran said.

The degradation of these critical resources, combined with threats to populations caused by natural disasters, disease and crumbling economic and ecosystems, he said, could ultimately have “cascading effects.”

“Environmental changes caused by global warming will not only affect human living conditions but may also generate larger societal effects, by threatening the infrastructures of society or by inducing social responses that aggravate the problem,” he wrote. “The associated socio-economic and political stress can undermine the functioning of communities, the effectiveness of institutions, and the stability of societal structures. These degraded conditions could contribute to civil strife, and, worse, armed conflict.”

In fact, Scheffran said, there’s evidence that such dramas are already playing out on the world stage – whether already affected by climate change or not.

“Large areas of Africa are suffering from scarcity of food and fresh water resources, making them more vulnerable to conflict. An example is Sudan’s Darfur province where an ongoing conflict was aggravated since droughts forced Arab herders to move into areas of African farmers.”

Other regions of the world – including the Middle East, Central Asia and South America – also are being affected, he said.

With so much at stake, Scheffran recommends multiple strategies for forestalling otherwise insurmountable consequences. Among the most critical, he said, is for governments to incorporate measures for addressing climate change within national policy. Beyond that, he advocates a cooperative, international approach to addressing concerns.

“Although climate change bears a significant conflict potential, it can also transform the international system toward more cooperation if it is seen as a common threat that requires joint action,” he said.

One of the more hopeful, recent signs on that front, he said, was the 2007 Bali climate summit that brought together more than 10,000 representatives from throughout the world to draft a climate plan.

“The Bali Roadmap has many good ideas, but was criticized as being too vague to induce a major policy shift,” Scheffran said. “Nevertheless, the seeming conflict between environment and the economy will be best overcome with the recognition that protecting the climate in the best interest of the economy.”

In addition to global cooperation, Scheffran believes that those occupying Earth now can learn a lot about the future by studying the past.

“History has shown how dependent our culture is on a narrow window of climatic conditions for average temperature and precipitation,” he said. “The great human civilizations began to flourish after the last ice age, and some disappeared due to droughts and other adverse shifts in the climate. The so-called ‘Little Ice Age’ in the northern hemisphere a few hundred years ago was caused by an average drop in temperature of less than a degree Celsius.

“The consequences were quite severe in parts of Europe, associated with loss of harvest and population decline,” Scheffran said.  “Riots and military conflicts became more likely, as a recent empirical study has suggested.”

However, as history has demonstrated, humans are quite capable of adapting to changing climate conditions as long as those changes are moderate.

“The challenge is to slow down the dynamics and stabilize the climate system at levels which are not dangerous,” Scheffran said.

He remains optimistic that this is still possible – in large part, because public awareness and educational efforts taking place today are making concerns about climate change a priority.

“Global warming receives now more public and political attention than a few years ago,” Scheffran said.

“Grass-roots movements are emerging in the United States for protecting the climate and developing energy alternatives, involving not only many local communities and companies but also influential states such as California, led by Gov. (Arnold) Schwarzenegger.”

Further evidence that the issue is being taken seriously at last, Scheffran said, is coming from the campaign trail.

“Congressional and presidential candidates now acknowledge that something has to be done to play a leading role on energy and climate change to not fall behind the rest of the world,” he said.

Reprinted from the University of Illinois at Urbana-Champaign.

Osvaldo Sala, director of the Environmental Change Initiative and the Sloan Lindeman Professor of Biology at Brown, and Pedro Flombaum, a postdoctoral research associate in the Department of Ecology and Evolutionary Biology at Brown, said the results confirmed tests charting how biodiversity affects aboveground plant productivity in artificial ecosystems. Aboveground plant productivity (ANPP) is the amount of biomass, or organic material, produced by plant growth.

But the Brown team also learned that the correlation between plant species richness – the number of plant species in a unit of area – and ANPP in a natural ecosystem was greater than had been expected. What that means, the researchers wrote in a paper published online this week in the Proceedings of the National Academy of Sciences, is that the greater the number of plant species, the more productive the ecosystem.

Conversely, species loss has a decidedly negative impact on ecosystems. This is especially true in light of the role ecosystems play in capturing the global warming gas carbon dioxide: The fewer the plant species in a given natural environment, the less carbon dioxide they capture.

“It’s a double whammy,” Sala explained. “We not only are disturbing our planet by putting more carbon into the atmosphere, but we’re reducing the ability of ecosystems to capture and store it.”

Sala and Flombaum conducted their experiments in the Patagonian steppe, a semiarid grassland located on the east side of the Andes Mountains in Argentina. They marked 90 plots, each containing three species of native grasses and three species of native shrubs. The team then removed a certain number of species from the plots and measured each revised plot’s productivity.

“The water is the same, the nitrogen is the same, the sunlight is the same,” Sala said. “What is different is the diversity of the plants.”

What the researchers also learned in their experiments, which ran from 2002 to this year, is that plant productivity in a flourishing ecosystem is enhanced because each species assumes a specific niche. Ecologists call this “niche complementarity.” The plants use the resources available to the whole system harmoniously, such as extending their roots at different depths in the soil, using different forms of nitrogen, and staggering when they photosynthesize.

“We are deeper into understanding the mechanisms of an ecosystem’s productivity,” Sala said.

Brown University, the InterAmerican Institute for Global Change Research, Agencia Nacional de Promoción Científica y Tecnológica and Argentina’s National Research Council funded the research.  

Reprinted from Brown University.

Modern agriculture and land-use practices may lead to major disruptions of the world’s water flows, with potentially sudden and dire consequences for regions least able to cope with them researchers at the Stockholm University-affiliated Stockholm Resilience Centre and McGill University have warned.

In a paper published April 1 in the journal Trends in Ecology and Evolution, Dr. Line J. Gordon of the Stockholm Resilience Centre and the Stockholm Environment Institute and Dr. Garry Peterson and Dr. Elena Bennett of McGill University argue that global water management has been focused too much on the “blue water” side of the hydrological cycle, neglecting the largely invisible changes humanity has had on so-called “green water.”

“Blue water is the part of the cycle we can see, like streams and rivers,” said Gordon, an assistant professor at the Stockholm Resilience Centre and the Stockholm Environment Institute. “This is as opposed to ‘green water’ in soil moisture, or evapotranspiration from plants, which agriculture can affect in significant ways.”

“Resilience” describes the capacity of social-ecological systems to withstand climactic or economic shocks, and to then rebuild and renew themselves. In their paper, the researchers look at the likelihood of that vital resilience being lost in the aftermath of catastrophic changes to the hydrological cycle that could be caused by agriculture and land-use practices.

“Our main point is that these effects aren’t necessarily going to result in gradual change,” explained Peterson, McGill’s Canada Research Chair in Social-Ecological Modelling, and assistant professor in the Department of Geography and the McGill School of Environment. “They can result in surprising, dramatic changes, what we call ‘ecosystem flips’ or ‘ecosystem regime changes,’ which can be very difficult or even impossible to reverse.”

According to Peterson, recent outbreaks of toxic algae blooms in Quebec lakes and off Sweden’s Baltic Sea coast are prime examples of ecosystem flips, the consequence of nutrients from fertilizers permeating the soil and running off into streams, lakes and oceans.

“As you get more and more nutrients in the soil you eventually get to a point where you can even completely stop farming and all the nutrients will still be there,” explained Bennett, an assistant professor at McGill’s Department of Natural Resource Sciences and the School of Environment. “You go past a tipping point where it’s very difficult to reverse.”

Ecosystem flips can have significant and sometimes devastating effects on human well-being, as global populations suddenly lose resources they are dependent on, said the researchers. Some of the most vulnerable areas on Earth are places like the drylands of sub-Saharan Africa.

“In some of these regions we risk two types of ecosystem flips, one that causes rapid soil degradation with dramatic effects on yields and farmers’ livelihoods, and another that affects rainfall and therefore also vegetation growth,” Gordon said.

“These are the places where populations are growing the fastest, people have the least amount of water per capita and are the poorest of any of the biomes of the world. They are also the regions most likely to be affected by climate change,” Peterson added.

As global demands for agriculture and water continue to grow, concluded the authors, it is increasingly urgent for scientists and managers to develop new ways to build resilience by anticipating, analyzing and managing changes in agricultural landscapes. Managing the green water component of the hydrological cycle is also important, as well as encouraging more diverse agricultural practices.

Regime shifts – a key issue at the Resilience2008 Conference, Stockholm Sweden, April 14-17 2008

The risk of catastrophic ecosystem regime shifts and the need for resilience-building are key issues at the upcoming international science and policy conference in Stockholm titled “Resilience, adaptation and transformation in turbulent times – preparing for change in social-ecological systems.”

Dr. Line J. Gordon and Dr. Garry Peterson will present their research at the conference. Keynote speakers include the father of resilience theory, Buzz Holling, leading political scientist Elinor Ostrom and renowned ecologist Steve Carpenter, to name a few. The last day of the conference will be devoted to a high-level policy forum on the implications of resilience science.

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Resilience2008 is organized by the Resilience Alliance, in collaboration with the Royal Swedish Academy of Sciences and the International Council for Science (ICSU). Local organizers are the Stockholm Resilience Centre at Stockholm University, the Stockholm Environment Institute (SEI) and the Beijer Institute of Ecological Economics.

Research by fish ecologists Dr Monica Gagliano (AIMS and James Cook University) and Dr Martial Depczynski (AIMS, Perth), with Dr Stephen Simpson from the University of Edinburgh and James Moore from JCU in Townsville, has found that fish with asymmetrical ear bones struggle to return to the reef.

The implications could be profound for the survival of reef ecosystems, which depend upon a rich biodiversity for effective function and health.

The research has been published today (Friday 7 March 2008) in the prestigious UK scientific journal Proceedings of the Royal Society*.

The stresses causing ear bone asymmetry may be closely linked to a combination of rising sea surface temperature and acidity, both caused by high atmospheric carbon dioxide levels, along with a range of more localised stresses.

Abnormalities in fish hearing structures may be interfering with a vital part of the animals’ life cycle. Most reef fish spend some time in the open ocean after hatching, before finding a place on the reef to settle and breed.

Researchers have only recently established how important sound is in guiding young fish to their homes. It is now known that fish at the end of their ocean stage “home in” on reef-associated sounds, such as the gurgling of fish and the snapping of crustaceans.

A sophisticated hearing system that enables fine distinction between frequencies is needed by young fish to determine where to go. Fish are not the helpless victims of currents and tides – they actively navigate.

The project examined damselfish, which are abundant on many reefs, including Queensland’s Great Barrier Reef and Western Australia’s Ningaloo Reef. As a group, damselfish are well-understood and provide a good model for other kinds of reef fish.

The scientists collected representative samples of hatchlings at their reef of origin. They later traced fish from the same cohort arriving on the reefs after the ocean phase, attracting them to traps broadcasting various sound frequencies, from high to low.

At hatching, 41 per cent had symmetrical ear bones (otoliths) and 59 per cent asymmetrical. When the team examined the otoliths at the settlement stage a few weeks later, far fewer asymmetrical individuals were found to have made their way back to a reef. The scientists also found that those with asymmetrical ear bones that did make it to the reef took longer to do so than their symmetrical counterparts.

“In our opinion, ear bone asymmetry in the early life stages of reef fish interferes with their capacity to find and settle on coral reefs,” Dr Gagliano said.

Vertebrate animals make sense of sounds by comparing differences in the acoustic signal between their two ears. To do this well, their ear structures must be relatively symmetrical. Asymmetrical ear bones do not appear to make the fish deaf, but they may interfere with the ability of the fish to hear effectively.

Dr Gagliano said that fish otoliths were a sensitive tool for studying the effects of environmental stress in fish. “Asymmetry has been used as a stress indicator for a long time, although in some contexts it remains controversial,” Dr Gagliano said.

“In our case, it looks like it is very reliable. Preliminary data indicate that if we increase the stress, the asymmetry of the otoliths will increase,” she said.

“There is a degree of asymmetry that is acceptable in the population – some is natural,” co-author Dr Depczynski said. “Not all the babies are created equal and not all of them are going to make it, even in pristine environments.”

The problem now is that an already high mortality rate among reef fish hatchlings is likely to rise even higher if young fish can’t navigate by sound.

At least part of the problem is likely to be linked to ocean acidification, although much more research needs to be done to examine the link. Fish ear bones, like their skeletons and many other kinds of structures such as reef-building corals, are made from calcium carbonate. When seawater becomes more acidic, there is less calcium carbonate available for building any calcium-based structure, including ear bones.

Acidity appears to be having a two-fold effect, creating a hostile marine environment and also robbing the environment of the building blocks of calcium-based structures. This has a direct effect on fish development and on their food sources, as many creatures the fish eat are also dependent on calcium.

While stress is part of life for reef fishes, new stresses are now being piled on top of existing ones and fish are showing the effects, according to Drs Gagliano and Depczynski.

*The Proceedings of the Royal Society paper is titled “Dispersal without errors: symmetrical ears tune into the right frequency for survival”. Link here.