Unnatural Histories
Genetically Modified Organisms
Welcome to the blog series Unnatural Histories!
The world’s a stage. So too in the natural sciences, George Evelyn Hutchinson talked of an evolutionary play being acted out in the ecological theatre. In the modern era, humanity has constructed a theatre unlike anything seen before. Crumbling walls, a leaking roof, the building is in a state of disrepair, collapse is imminent. With over a million species presently threatened with extinction, most of the contemporary performances in this ailing venue are tragedies.
Yet hope springs eternal.
Rewilding is an attempt to restore the theatre to its former grandeur. Some have argued this to be pure folly - we lack the resources and the vision to pull off such an ambitious rebuild. Besides, nature does not stand still. The world as it was before is confined to the annals of history. The world as it will be resides solely in the haze of future possibilities. In this series we will describe the architecture of the modern ecological theatre, explore how this new environment has influenced the evolutionary stories of its actors, and speculate on the catalogue of dramas that await us. Curtain up!
Contents
1. The Hitchhikers Guide
2. Dazzling Urbanites
3. Distress and Despair
4. Pick Up the Pieces
5. Do Not Disturb
6. The Bountiful Harvest
7. Captivated
The Hitchhikers Guide
Don’t Panic
~ Douglas Adams
The concept of ‘survival of the fittest’ inevitably draws the same astute question: why is there so much diversity? This is an excellent question that, for the most part, baffles scientists. Explaining patterns of diversity is a major branch of the biological sciences, and answers to date are largely underwhelming in their explanatory power and often mind-bogglingly complex. Critics have a much easier time of it. If what you say about Darwinian evolution is true, the doubters assert, why does not one species dominate all others to the point of exclusion? Why isn’t there just one type of frog, the fittest, most well-adapted frog that drives all others to extinction?
In the modern era, the questions surrounding biodiversity and species coexistence are not as hypothetical as one would hope. A mass homogenization is taking place; a global experiment with potentially disastrous consequences. Animals and plants are being moved around the world both accidentally and purposefully. The end result is the same; something somewhere it’s not supposed to be. Instantly, the landscape changes - species that were once kings of their respective domains suddenly face a new challenger. They must fight tooth and claw to remain ‘the fittest’, but nothing in their evolutionary history to date has prepared them for this novel threat. Native species are completely naive to the alien’s tricks and tactics; powerless to prevent the newcomer from taking root, and defenceless against their rapid spread. Never underestimate the element of surprise. For the locals, the situation can only be described as dire. As we speak, invasive species are driving extinctions, reducing biodiversity, and in certain extreme cases, leading to entire collapse of ecosystems.
Ecosystems are intricate, interwoven fabrics, such that you cannot alter one aspect without having knock-on effects that percolate throughout the biota. Herein lies the destructive power of invasive species. Their impacts are often so far-reaching they are near-impossible to predict, and have only begun to be quantified. The most straightforward impact of invasive species is direct competition with residents that occupy the same niche. Indeed, a loose ‘one in, one out’ policy was elegantly described in the 1960s by researchers studying colonisation and extinction dynamics on islands. This delicate balancing act however, assumes that the system in question exists in a serene, idyllic state of equilibrium. Invasive species are, by definition, a severe disruption to the equilibrium, and tend to exert a much more damaging influence on local fauna. The result then, is typically more of a ‘one in, many out’ state of affairs. We have only scratched the surface when it comes to documenting the cascading, unpredictable impacts of non-natives. However, despite only the tip of the iceberg in view, we can readily surmise that if we do not divert our course, this thing is big enough to sink us.
Like a Duck to Water
May 3rd, 1890 - a transatlantic steamer pulls in sight of Ellis Island. The Statue of Liberty, dedicated only four years prior, is perhaps the only recognizable feature of the Manhattan skyline. It towers above the Hudson Bay, glistening water meets glistening steel. Passengers disembark, their necks craning upward to take in the spectacle. A mixture of awe and wonder strikes all that come to these shores. A new land, full of promise. But for some, the change of scenery is too drastic. Many long for the simple pleasures of home; we all yearn for the familiar.
A plan has been formed. A newly established amateaur dramatics society is keen to bring a piece of the old world to the new. Even small things, they contend, can alleviate the homesickness they and their families have developed over the preceding years. They proudly march with cages to their local green space, central park, and select a suitable spot. Eighty birds, representing a dozen or so of each species mentioned in the works of Shakespeare, are released, set loose in New York City to take root and multiply.
And they do take root. They do multiply. Now when little-Englanders reach the land of opportunity and take in their surroundings, the avifauna will no longer be entirely alien. Whenever one of the huddled masses feels lost or isolated, a glimpse toward the heavens will provide them with comfort and cherished memories. By any standards it was a veritable success. But in true Shakesperian fashion, a tale with innocuous beginnings will come to end in tragedy.
By the mid-20th century, one of these transplanted birds, the European starling, had consumed the continent. The starlings have out-competed native bird species for resources, including nesting sites and food. The locals never stood a chance. In response, some species have conceded defeat by way of rapidly evolving shorter bills and smaller body sizes such that their diet and habitat requirements no longer overlap with the European invader. Despite this flexibility, many native bird populations in North America have suffered precipitous declines.
Part of their success in North America stems from their ability to thrive in urban areas. Even in the densest concrete jungle, starlings can achieve flocks that are over a million birds strong. And they shit on everything. Those unfortunate enough to leave their car parked on the street under a roost tree wake up to a mountain of guano with not even a single inch of bodywork visible. Shooting and trapping, as well as the reintroduction of peregrine falcons and Cooper’s hawks, have had little to no effect. As we stand, scenes in Manhattan now resemble less Shakespeare, and more Alfred Hitchcock or one of the plagues of Egypt.
Citizen Cane
August 9th, 1935 - a cargo ship docks in Cairns harbour. The 102 toads on board are documented by customs and promptly transported to the arable region of Queensland. The toads are to serve as a biological control agent against a voracious beetle pest that is decimating Australia’s sugar production. The beetle itself is a non-native, hailing originally from Europe. The hope is that these South American toads can suppress the beetle invasion; fight fire with fire.
As it turned out, the toads ate everything but the beetles. With no native predators and an abundant source of naive prey sources, the toads proliferated. And they spread. Within ten years the toads had reached the Northern Territory, within twenty years they had colonised the western half of the continent. With sugar cane beetle populations largely unaffected, the Australian government now has two disastrous invasions to deal with.
Human-mediated colonizations have myriad consequences. Indeed the distinction between an invasive species and merely an introduced species is their perceived impact. Once an alien species reaches foreign shores, the outcome is not certain, but there is no going back - the walls have been breached. Cane toads are most certainly invasive. They are considered one of the most destructive non-native species on the planet. Each year, millions of dollars are spent on culling, trapping, and toad-proof fencing to mitigate their impacts. But the integrity of native ecosystems has already been compromised, at this stage damage-limitation is the best we can hope for.
Much of the cane toad’s detrimental impact derives from its acute toxicity. Anything that tries to eat them, mistaking it for something edible, suffers fatal or sub-lethal poisoning. For many predators the consequences are disastrous. Again, some local species have attempted to move out of the way of the steamroller by way of rapid adaptation. Evolution thrives under pressure. Black snakes, for instance, although certainly reduced in numbers as a result of cane toad poisoning, are over the worst and likely to recover. Their solution to the problem? Smaller heads. Snakes with small heads are not capable of stretching their jaws wide enough to consume a toad large enough to kill them. Natural selection at breakneck pace - snakes with big heads die, snakes with small heads survive; future generations of snakes all have small heads.
Several other species are maintaining the same head size and instead developing resistance to the toad toxins, and some have learned to stop viewing toads as prey items. Encouragingly, both of these novel adaptations can be induced through cleverly designed conservation measures; scientists are presently deploying food laced with small amounts of toxins in the hope that resistance is more speedily acquired. We are learning - that is perhaps the only positive one can take from this episode. We have learnt a tremendous amount about the physical process of invasion, the ecological and evolutionary responses of native fauna, and evaluating mitigation strategies. The hope then, is that we have learnt enough from our mistakes to prevent this from happening again. Or at the very least be more prepared when it does.
Scorched Earth
June 20th, 1938 - a cargo ship docks in the port of Mobile, Alabama. On board are thousands of ornamental plants, set to adorn gardens and windowsills across the nation. With such a profusion of goods, it is rather unsurprising that the colony of small, red ants taking temporary residence at the base of a potted Hibiscus went unnoticed by customs. Once ashore, the colony found a suitable patch of earth to set up camp, largely unaware of how far they had travelled, and, as ants do, began to forage. From humble beginnings, as they say.
Fiercely aggressive, and forming huge super colonies, the red imported fire ant quickly outcompeted and displaced native ant species. And they spread. Within twenty years the ants had reached Texas, Louisiana, Mississippi, and Georgia. Despite their early flourish, there remained a cautious optimism that the ants would not spread much beyond the southern states on account of the harsher winters experienced in the rest of the continent. However, a few decades later it became apparent that the ants were evolving a higher tolerance to cooler temperatures, facilitating their northward march.
Although we often focus on the detrimental impacts and evolutionary responses of native species to introductions, the invaders are subjected to perhaps an even greater pressure, that of being thrown into a completely alien environment. Again, evolution thrives under pressure. Within fifty years the distribution of fire ants in North America was transcontinental. In a matter of a few generations, fire ants evolved to be more aggressive than in their native range, an extremely useful trait when attempting to dislodge native incumbents. At the same time, the ants perfected a novel reproductive strategy to expedite their expansion; “budding”, a process in which a group of workers and a queen leave the main colony to establish new ones nearby, allowed the ants to spread into unoccupied territory at a much faster rate.
Eating virtually anything and everything, as well as damaging the roots of several important cash crops, the accidental introduction of fire ants to North America has become an invasion of colossal proportions. Since the Mobile ‘landing’, human trade routes have brought fire ants to the shores of Asia and Australasia, and the same unfortunate drama is playing out again and again. Fire ants are spreading across China, Taiwan, Australia, and New Zealand. The invasion is now a global one, with no end in sight.
Coda - Bullfrog Moan
Have you ever woke up with them bullfrogs on your mind?
I got the bullfrog blues and I can’t be satisfied,
Mexico got ‘em,
Japan got ‘em,
Cuba got ‘em,
Jamaica got ‘em too,
I got the bullfrog blues and I can’t be satisfied,
Italy got ‘em,
France got ‘em,
Brazil got ‘em,
the Netherlands got ‘em too
I got the bullfrog blues and I can’t be satisfied,
Canada got ‘em,
China got ‘em,
Brazil got ‘em,
And Columbia got ‘em too,
I got the bullfrog blues and I can’t be satisfied,
Uruguay got ‘em,
Venezuela got ‘em,
Argentina got ‘em,
And South Korea got ‘em too.
Dazzling Urbanites
The rats have all got rickets
They spit through broken teeth
~ John Cooper Clarke
As a rule, urbanisation is bad for wildlife. Rather intuitively, the conversion of natural habitat to a mosaic of concrete, metal, and tarmac leads to population declines of many species and an overall loss of biodiversity. Green spaces become few and far between; animals struggle to survive in the remnant fragments. Their behaviour and reproductive cycles are severely disrupted by the incessant noise and fast pace of modern human societies. For many, it is nigh on impossible to keep up.
A small minority of species however, thrive in the big city. Some creatures have successfully adapted to the urban lifestyle and taken advantage of the new, formidable landscape that others have been driven out of. After all, it is not strictly the loss of habitat that results from urbanisation, but more so a dramatic shift in habitat. Survival of the fittest plays out in concrete jungles like any other. Darwinian selection applies to Accra just as much as it applies to Amazonia. The rules of the game have not changed, merely the theatre. And in such a novel setting, the strategies for success are often quite different from those that emerge in forests or prairies. Squirrels, pigeons, mosquitos. These are the new superstars that tower over the competition. All have found a way to not only scrape by, but to dominate.
Bright Lights, Big City
For the first 25 years of my life I lived in a city. First London, the Big Smoke. A small garrison on the outskirts of the Roman Empire, Londinium has become one of the largest urban centres in the world. A place of kings and playwrights, football fans and fishmongers. As a budding biologist, the natural history museum in south Kensington held particular appeal, with its breathtaking Victorian architecture and mesmerising collection of curiosos. At 18 I left London for Sheffield, the former steel capital of the world, the current home of snooker. Built on seven hills, steep cobbled streets wind their way through row upon row of terraced houses. Quintessential Yorkshire. Good beer abounds. Yes I do like cities. They have character, they have goings on. There is magic in the hot, noisy air.
But I yearned for something different. As a young man I decided to emigrate to southwest Virginia, in the heart of the Appalachian mountains of North America, to pursue my doctorate degree. I was to study salamanders, a charismatic group of amphibians that includes newts, axolotls and hellbenders. My choice of study location was simple - the Eastern US has more salamanders than anywhere in the world. The university resided in a small, isolated town, several hours from the nearest metropolis. In every direction, a veritable paradise of cool mountain streams, moss-draped boulders, and humid forests that stretch for thousands of miles. So much to see, and so much different from whence I’d come.
Of all the new sights and surroundings, the one that stood out, the one that seemed most unfamiliar, was the darkness. At night it gets dark. Properly dark. A darkness I had never experienced before. To a lifelong city-dweller it was unsettling. Without any contrast, I had taken the night lights of cities for granted. I had become accustomed to 24-hour illumination - neon signs, street lamps, blue-tinged, starless skies. These collective phenomena have been jocularly dubbed ALAN by urban biologists studying their effects - ALAN stands for Artificial Lights At Night.
ALAN is a form of pollution that has been found to have detrimental effects on many species including humans. Exposure to ALAN has been linked to increased risk of obesity, diabetes, and cardiovascular disease, and even some types of cancer. More intuitively ALAN also disrupts circadian rhythms and alters the behaviour of animals. Much can be drawn from the contrasting proclivities of human beings in urban and rural settings. Wildlife is similarly more nocturnal in cities; birds can still be heard singing at midnight, leaving them exhausted and confused. Flowers open at odd times of day because they do not receive the appropriate environmental cues; if pollinators do not respond in kind, the plant’s reproductive success is put in serious jeopardy.
On beaches around the world, sea turtle hatchlings emerge from their nests in the wee hours. They are timing their emergence to avoid the myriad avian predators that are active during daylight hours. Hatchlings have learnt to follow the light of the moon reflecting off the ocean surface to reach the safety of the ocean. However, on developed coastlines, the ALAN emitted from raucous bars and late-night shops completely swamps out anything the moon can muster. Disorientated, the hatchlings march toward the town. Even if they manage to avoid being run over by traffic or falling down storm drains, they will eventually succumb to dehydration.
Geckos are now a ubiquitous feature of cities in tropical climates. Their adhesive toe pads allow them to navigate walls and windows without trouble. The vertical surfaces that dominate urban landscapes offer no challenge, and the heat-absorbing property of concrete provides cold-blooded reptiles with enough warmth to remain active almost indefinitely. Moreover, geckos are one of the few species to benefit from ALAN. Artificial lights attract moths, their primary prey item, from far and wide. At dusk, every security light and shop sign turns into a banquet. These small, unassuming lizards have never had it better. With the increased availability of food, and the ease with which it can be obtained, gecko populations in urban areas have resources to spare. Females lay twice as many eggs as their counterparts in forested habitats, and numbers have skyrocketed.
Skyscrapers
Pigeons, above all other avian species, have made cities their home. The pigeon has a long and fascinating history, dating back over 5,000 years. The wild ancestor of the domestic pigeon is the rock dove, native to Europe, North Africa, and parts of Asia. The ancient Egyptians were the first to domesticate pigeons, using them for food and as messengers. The Greeks and Romans did the same. Genghis Khan used them. Right up until the First World War, carrier pigeons were used to transmit military messages across battlefields during conflict. With the advent of the telegraph and later, the telephone, the use of pigeon post declined.
Today, domestic pigeons can be found throughout the world and are still used for racing and as pets. Feral populations of domestic pigeons can be found in virtually every major city. Their long historical association with humans has predisposed them to urban life. They quite content using buildings, bridges, and statues as roosting and nesting sites. They will eat virtually anything that humans drop or leave unguarded. Urban pigeons have larger brains than their rural counterparts, possibly due to the cognitive demands of navigating such a complex, highly dynamic landscape. They are so successful, train stations and office buildings will spend considerable money covering every possible perching spot with rows of spikes as a deterrent. But such attempts are largely futile.
Pigeons are not the only birds to conquer the concrete jungle. Crows, house sparrows, and European starlings have all successfully adapted to urban environments. The key to success in all these cases appears to be an indiscriminate nature. All of these species have a cosmopolitan diet; they will eat most things and are not above scavenging from trash piles and dumpsters. And all of these species will build a nest anywhere they can. This generalist, flexible life-style has allowed a handful of birds to achieve extraordinary population sizes and exist at very high densities. Apart from chickens, house sparrows are the most common bird in the world. Starlings are next. For those that can hack it in the hustle and bustle of cities, the rewards are great.
Peregrine falcons, once an endangered species, almost driven to extinction in the mid-half of the 20th century, have recovered. And they have cities to thank. From New York to New Delhi, they gleefully take advantage of the hyper-inflated populations of their prey. They nest on some of the tallest buildings in the world. Being so isolated, their growing chicks enjoy an unprecedented level of safety. The multistory buildings that now dominate city skylines also provide the perfect vantage point from which to swoop down and snatch an unsuspecting pigeon in flight. For Peregrines, cities are sanctuaries, a refuge from the threats that drove their historical declines - pesticide poisoning, shooting, and egg poaching. Perhaps more a savage indictment of our impact on wild areas than a testament of the welcoming nature of urbanity.
Any Port in a Storm
Not all cities are the same. The aforementioned Sheffield, for instance, proudly claims to be the greenest city in Europe. Parks, gardens, and remnant forest dot the industrial landscape. Such a mosaic of semi-natural areas can lessen the harsh realities of urban living, providing food, water, and refuge for native wildlife. Myriad species benefit from Sheffield’s gardens. Back yards often contain a tremendous diversity of plants and habitats. Indeed in recent years, conservationists in Britain have successfully shifted public opinion to move away from manicured lawns toward more ‘wildlife friendly’ gardens. Planting native flowers attracts bees and butterflies. In turn, the insects will attract birds and bats. It doesn’t take much to create an ecosystem; once you set the ball rolling, nature is good at building from the ground up. Some homeowners go so far as to construct habitat features in their gardens to support particularly affable species - nesting boxes for hedgehogs, ponds for frogs and newts, and rock piles for lizards and snakes.
However, ornamental plants, non-native species from around the world that are cultivated for their aesthetic value, remain a staple of the English green space. And this foreign window dressing can completely negate any of the benefits that an urban garden might confer. Many ornamentals are chosen for their hardiness, as well as their beauty, and this trait becomes a source of all problems. Case in point, Japanese knotweed. Put it in the ground and you have a pretty bush that lives for years and requires little to no care. But you plant it at your peril. Japanese knotweed has reached infamy around the globe as an extremely destructive invasive Once it becomes established, all hope is lost. Knotweed is so pervasive it can alter soil chemistry and disrupt nutrient cycling. It develops such a monopoly on water and mineral resources, that many native species are driven out. The presence of knotweed in your garden has the power to reduce property value. Knotweed is a particularly extreme case; hydrangeas from Asia - an easy to maintain bush that yields voluptuous florets of violet and pink - offer a more typical example. They have been linked to the decline and loss of native plants in parts of the United States where they festoon front lawns. Moreover, these ornamentals are not attractive to native pollinators or wildlife. They take up space, but provide nothing for the local fauna. Ornamental gardens can be as inhospitable as an unadorned square of asphalt.
Distress and Despair
coming soon!
Pick Up the Pieces
coming soon!
Do Not Disturb
Work is of two kinds:
first, altering the position of matter at or near the earth’s surface relative to other matter;
second, telling other people to do so.
~ Bertrand Russell
Competitive Exclusion
Quantitative biology experienced a golden period in the first half of the 20th century. The fields of population genetics, predator-prey dynamics, and community ecology all emerged and flourished in the interwar years. Fueled by the political climate, biologists understandably had Darwinism - survival of the fittest - at the forefront of their minds. Fear gripped nations. Never has the cutthroat nature of nature spilled over into human societies more so than under fascist and communist regimes. In 1934 Adolf Hitler obtained the presidency in Germany. In the same year, a soviet scientist was carefully examining petri dishes in his Moscow laboratory, unravelling one of the fundamental rules of life.
As the western world braced itself for yet another global conflict, Georgy Frantsevich Gause published “The Struggle for Existence”. How very apropos. In it, he outlined the competitive exclusion principle. Put simply, two species competing for the same resources cannot coexist. According to this principle, if two things occupy the same ecological niche, one will inevitably outcompete and displace the other. This is what he had observed time and time again when pitting various bacterial strains against each other. Invariably, there was only one outcome, only one winner. But this raises an interesting question. Why is it that in nature, we see millions of species, many of which appear strikingly similar to the eye? If survival of the fittest and competitive exclusion are truisms, then how do we explain diversity? The simple yet counter-intuitive answer is that competition does not exist in nature. At least not for very long.
Species avoid competition by ensuring that their niches do not overlap. More accurately, natural selection will act to reduce competition between species by selecting for divergent niches. This is often achieved by dividing up the available resources like slices of a pie. With a million species, the portions become very small, i.e., species tend to become very specialised on one particular ecology. Of course, everybody wants more pie, but such is the nature of specialisation that if you try to compete with someone else for their slice, you risk losing your own. This is essentially how biodiversity is maintained. Darwin first observed resource partitioning amongst the finches on the Galapagos Islands. The various species had evolved different beak sizes and shapes, which allowed them to specialise on different types of food. Therefore, even though the finches shared the same habitat, after several generations of natural selection, they were no longer in direct competition. In the greater Antilles, a group of small lizards have undergone a similar pattern of divergence. Members of the genus Anolis like to forage on vegetation; to reduce niche overlap on the crowded Caribbean islands, species have partitioned their habitat vertically. One species forages in low-lying shrubs, one species forages on tree trunks, and one species forages high in the canopies. As a result of this specialisation, the lizards do not interfere with each other.
Humans are displacing all other life on earth. We are the ultimate generalists. We want all of the pie. Our ecological niche has become so vast that we have put ourselves into direct competition with virtually everything else. We deforest huge swathes of land for fuel and wood products. We clear acres and acres for agriculture that provides food only for ourselves. Thus, the ultimate resource that humans compete with other species for is space. As a result, a large part of conservation acts to partition resources spatially, to restrict human activities in certain regions, and thereby facilitate coexistence. Protected areas like national parks are a form of spatial segregation. On a smaller scale, conservationists will fence off nesting beaches for turtles and shorebirds, or construct hedgerows at the edge of farm fields to provide habitat for bees and butterflies. We spend billions of dollars to combat extinction. It should not be surprising that this work is expensive. We are, after all, trying to cheat one of the fundamental laws of biology.
Goldilocks
Despite largely negative connotations of the word ‘disturb’ in common parlance, in the biological world, not all disturbance is bad. In fact, environmental disturbance is one of the primary sources of biodiversity. In many instances, disturbances such as fire, flood, or drought can create opportunities for new species to establish themselves in previously occupied niches. This allows for coexistence of multiple species, as each is able to occupy the niche under different conditions. In essence, the resources are partitioned in time. When a tree falls in a forest it creates a clearing that rapidly accumulates a suite of fast-growing, light-loving plants. These plants will eventually be shaded out and replaced. It is only through repeated disturbance events that such species can persist. A mature forest is only the last stage in a long succession of vegetative communities that emerge at various times post-disturbance.
Without disturbance events, i.e., in a static environment, a handful of species will be able to outcompete all others leading to a depauperate community. Walking through a mature pine stand will reveal this truth; the pines have excluded all other trees and their dropped needles prevent the formation of any herbaceous understory. Without disturbance, nature is quite boring. However, if the disturbance events are too frequent or too ferocious, then no species will be capable of taking root, resulting in an equally monotonous landscape. A coral reef ravaged by an intense ocean storm is a sorry sight indeed. There are few survivors, and the once bustling coastal community resembles a ghost town with only the echoes of life. Humanities impact on the planet is also in this category of “too much disturbance”. Observations on the temporal ebbs and flows of biological communities have been formulated into an ecological theory, namely the intermediate disturbance hypothesis, positing that a moderate level of disturbance in an ecosystem promotes the highest species diversity. Moderate disturbance creates new opportunities for species to colonise and prevents any one species from becoming excessively dominant without causing excessive damage to the established ecosystem.
The intermediate disturbance hypothesis makes conservation very difficult. The word conservation itself is troublesome. ‘Conserve’ means to maintain constant. In physics, the word is used to describe laws for things that don’t change: the conservation of energy, the conservation of angular momentum. Biological systems however, are inherently dynamic. To ‘conserve’ an ecosystem or a species therefore, does not make much sense, it is an exercise in futility. As a result, sometimes when we try to protect those imperilled or endangered, our efforts do not have the desired consequences. In an attempt to coddle nature, we remove all sources of disturbance and continue to lose biodiversity as a result. The goal of conservation should not be to eliminate disturbance, but to remove the extreme, chronic disturbances of humanity whilst keeping the historical, natural disturbance regime that acted as the crucible for the biotic communities we are trying to protect. This kind of management is a delicate balancing act that often requires constant intervention, constant artificial manipulation, to mimic the processes of the past. What we are actually trying to conserve therefore, is the dynamic properties of biological systems, the dynamism that creates and maintains diversity. Unfortunately, many of these dynamic processes have already been undermined, such that our goal in the 21st century is less one of conservation and more one of restoration. As one can imagine, the latter presents a much greater challenge and price tag than the former.
Detritus
Another challenge for biodiversity conservationists is that most of life’s processes are invisible to the naked eye. The vast majority of living things are microscopic. Bacteria, viruses, protozoa, archaea, all go about their business unseen. But the effects of these creatures are impossible to miss, and indeed are fundamental to the working order of the natural world. Without them, the cogs of life would grind to a halt. For instance, the very existence of plants would not be possible without the cycling of nitrogen through its various forms - from ammonia to nitrites, and from nitrites to nitrates. Despite the abundance of nitrogen gas in Earth’s atmosphere, plants have no way of exploiting it. To be taken up by roots and used for vegetative growth, the nitrogen must first be transformed. Sadly for plants, nitrogen gas is incredibly stable. Occasionally a bolt of lightning is powerful enough to rip apart nitrogen atoms and oxidise them, but this is hardly a reliable source. No, the only effective means of nitrogen fixation is the respiratory and digestive actions of microbes. Without microbes there would be no plants. Without plants there would be no animals. Single-celled organisms prop up the entire chain of being. Conservationists would be wise not to forget this.
Even larger organisms can often go unnoticed. Species that live underground are routinely neglected by biologists and the public alike when considering the richness of the natural world. Out of sight, out of mind. But again, just because humans fail to notice them does not mean that they exert no meaningful impact on ecosystem processes. Take a shovel and drive it into different parts of the world, and you will find a tremendous variety of soils. One might conclude that differences are largely the result of geology or historical seismic activity, volcanoes and the like. But this is not the full picture. Biology generates far more diversity than geology could ever dream of, and the fingerprints of life pervade the soil as much as they do a coral reef. The success or failure of agriculture can hinge on the humble earthworm, nature’s plough. In temperate regions they comprise more biomass than any other subterranean species and their activity breathes life into soil. The feeding and respiration of earthworms promotes the decomposition of leaf litter, cycling nutrients back into the soil to be reused by plants. The extent of their burrowing dictates how quickly water drains through the soil, thereby allowing plant species to grow that would otherwise drown. Human activities have caused a precipitous decline in earthworm numbers across the globe - farmers and environmentalists should both be worried.
The last group of organisms that we overlook at our peril are those of the past. Nature does not exist in a vacuum, and the properties of the present day hinge ultimately on what came before. The clay that accumulates in the slow moving parts of rivers or the limestone that demarcates the boundaries of an ancient seabed; many of the recognizable rocks and mineral soils are formed by the deposition and compaction of biological material. Clay would not exist without algae, limestone would not exist without snails. The ground we stand on would be far less rich if not for the three billion years, the countless generations, of life and death that have decorated the planet’s surface. This is perhaps the biggest challenge for conservation. Certain features of quote unquote ‘healthy’ ecosystems are irreplaceable. If they are lost it would take another three billion years to get them back. In time we will perhaps develop an alternative to fossil fuels, a synthetic substitute or novel technology that allows us to ignore our unabated pilfering of the earth. But if we do not learn from our mistakes then we do not really solve any problems, and I worry that an ecosystem will be more difficult to keep running than a 2004 Honda Civic.
The Bountiful Harvest
coming soon!
Captivated
Staring through the bars of a Cuban jail, Alejandro remembers the good times. A full moon illuminates the unadorned brickwork that surrounds him. A mirror would make the space seem larger, he muses. Imprisoned since he was a child, each day that passes, each moment that transpires, intensifies his desire to experience something new. Such sameness fuels the yearning for otherness, regardless of what that entails. Change is life-affirming. For Alejandro, the monotonous regularity of his existence threatens to consume him. He rests his head on the pillow, grateful to see the back of another hollow day. With a deep sigh, he closes his eyes.
There is no greater sorrow than to recall happiness in times of misery
~ Dante
Desperate Measures
As a boy, I have fond memories of taking the Bakerloo line to Regent’s Park. A particularly picturesque corner of north London, a stone’s throw away from Bkaer Street and the throngs of Conan Doyle fans who have made the pilgramige to admire the terrace house supposedly inhabited by the mythical detective. Here, we are also not too far from King’s Cross, where another blue plaque afixed to the wall demarcates the entrance to platform nine and three quarters. Appropriately, the British Library sits in between these two infamous locations of british literature. But I am not here for any of these attractions. I am here for the zoo. Opened in 1828, the ZSL facility lays claim to being the oldest scientific zoo in the world. But at such an age, I was not interested in science. I wanted to see something cool. Upon entering I would race to the reptile house. As a little Englander, snakes, frogs, and lizards epitomize the transporting power a zoo can posess. On the outside, an unassuming shed. On the inside, a menagerie of exotic animals from every corner of the globe that, by all rights, I should have never had the opportunity to see. But here they were. Nose pressed against the glass, I was in awe.
I still hold that the inspirational woder a zoo can bring to impressionable children is enough justification for their existence. However, in recent years, due to funding pressures and animal rights activism, zoos have had to take on a more utilitarian role. The proportion of animals in zoos that are endangered species has increased dramatically. Many zoos now bill themselves as conservation ‘arks’, where punters now marvel at the good work they are doing. Conservationists often view captive rearing in zoos as a last-resort intervention, one final throw of the dice to prevent a species from blinking out of existence. Through the release of captive animals back into their natural habitats, it is hoped that the declines of wild populations can be curtailed and perhaps even reversed. Captive rearing is a popular strategy in conservation because it appeals to people’s emotions. Seeing cute baby animals being raised in captivity is heartwarming and can attract public attention, which in turn can attract sponsors who are impressed by the large numbers of animals being raised. However, captive rearing is not a golden bullet for conservation. For one, the majority of reintroduction events have failed. Failure typically results from inadequate knowledge of a species’ biology, interventions that occur too late when the situation is already beyond hope, or simply bad luck. In many instances, failure occurs from a combination of all three. Even for reintroductions that succeed, the financial cost of rearing and release leads some to question whether such extreme measures are worth it.
Captive rearing alone cannot address the complex problems facing endangered species. For one, it fails to address the root causes of population declines. Species have been extirpated from the wild due to habitat destruction, pollution, disease, and climate change. If these threats persist, releasing captive reared animals will amount to nothing. To invest in captive reading when the underlying problems have not been effectively mitigated is putting the cart before the horse. The situation gives rise to puppet species - species that are no longer capable of surviving in the wild on their own. Their continued existence relies wholly on people painstakingly raising them in captivity, only to then release them into a now inhospitable landscape. They are released to their certain deaths, and once the last individual succumbs, the process repeats. Year on year. It becomes similar to farming, but instead of raising animals to provide food for humans, we are raising animals to provide food for an invasive mink or blue catfish. If captive rearing is deemed necessary, it should be done with a clear understanding of its limitations and costs.
A False Sense of Security
Captive rearing can have unintended consequences on the development of animals, which may impact their chances of survival in the wild. Animals in captivity often develop morphological abnormalities caused by inadequate nutrition, lack of exercise, or exposure to stressors that are not present in their natural habitats. Captive animals are also more susceptible to disease outbreaks than their wild counterparts. This is partly due to the stress of captivity, which can weaken the immune system of animals. Additionally, the close proximity of captive animals can facilitate the spread of infectious diseases, making it difficult to control outbreaks once they occur. Even when captive animals appear healthy, there may be invisible problems brewing. Many birds, insects, and amphibians rely on the earth’s magnetic field and the night sky to navigate during their annual migrations. Much of this directional know-how is imprinted on the animal at a very early age. For animals that spend the first few months or even years of their lives in a windowless rearing facility, their spatial awareness is nil. They are then transported several miles to a release site, a completely foreign landscape, and left to figure it out on their own. Instantly lost, most captive animals wander aimlessly until they die from dehydration, starvation, or if their wandering takes them to a highway, vehicle collision.
One of the most concerning issues with captive rearing is that it can inadvertently select for captivity. Darwinian selection is omnipresent. Just as we have intentionally selected for desirable characteristics in livestock (large udders in dairy cows, fast growth in broiler chickens), we have unintentionally selected for certain traits in captive populations of endangered species. Captive rearing almost invariably leads to animals becoming more tame. Whilst tameness is extremely desirable for companion animals such as dogs and cats, it is completely at odds with the survival instinct. Tame animals will be more likely to naively approach humans or other natural predators, and often become overly dependent on humans for food and shelter. Without the need to hunt or fight for territory, captive animals typically exhibit reduced aggression and reduced exploratory behaviour. Particularly for social animals that learn these behaviours from parents or siblings, animals raised in captive isolation can never acquire the skill set to survive in the real world. Suddenly they are plunged into a world where they must learn to find food and shelter on their own. This rarely goes well.
The Family Inheritance
In the 1990s, the wild population of Florida panthers was estimated to be as low as 20 individuals. With such limited options, the panthers were forced to mate with siblings and cousins; chronic inbreeding is a salient problem for critically endangered species. This particular inbreeding depression manifested as heart defects and low sperm counts - with both survival and reproduction in jeopardy, the panther’s prospects looked dire. For such species that have dwindled down to perilously low numbers, captive colonies provide a means to preserve genetic diversity and mitigate the threat of inbreeding. The Chatham Island robin, the Iberian lynx, and the American bison have all been rescued, genetically speaking, through captive efforts. However, given budget and space constraints, captive colonies may be as small or smaller than the wild populations they hope to bolster. As such they can be equally susceptible to inbreeding and its associated problems, and sometimes unintentionally make things worse. If captive colonies are themselves inbred, then they stand little chance of surviving upon release, let alone acting as a species’ saving grace. For example, the small size of the original captive colony for the California Condor was its downfall - poor hatchability and a high mortality rate among young birds resulted in several decades (and more than several million dollars) of next to no impact on the wild population.
A lesser known genetic risk of species reintroductions is outbreeding depression. Whereas inbreeding causes problems from the mixing of genes that are too similar, outbreeding causes problems from the mixes of genes that are too different. The breeding of individuals that are distantly related can sometimes result in incompatible combinations of DNA that produce offspring that are either completely non-viable, or have severely reduced fitness. Rio Grande cutthroat trout were once widespread in the southwestern United States, but their numbers have declined precipitously due to habitat loss and competition with non-native trout species. In an effort to save them from extinction, individuals from a stable population were transported thousands of miles and introduced to increase the genetic diversity of a struggling population. The resulting hybrid offspring however, did not survive to reproductive maturity. We live in an age where plants and animals travel unnatural distances. Through human means, whether intentional or unintentional, we have shuffled the deck of life in ways never before seen. The myriad problems caused by so-called invasive species are well known. The decimation of Australia’s native fauna following the introduction of the cane toads or the ongoing destruction of North American forests at the hands of the emerald ash borer serve as cautionary tales. The unforeseen consequences of releasing animals into new places should be on the forefront of the minds of conservationists desperate to make a difference by any means necessary. We play god with nature at our peril.
…
At midnight a faceless guard approaches and tells Alejandro to collect his things. The powers that be want him to hack it in the real world, to try and make something of himself, for the benefit of society. On order of the judge he is to be released in three hours. No time to prepare, the time is now. Sink or swim. He is flooded with emotions. Released. Thoughts of freedom fill him with joy. But the joy is soon replaced with fear. Released. Released to a world he does not know. Released to a world that took his parents. How will he live? How will he survive? A set of keys jangles, the cell door swings open. He surveys the four walls one last time, before gazing out at the moon and his destiny. He gulps, and steps into the unknown.