The native Red Squirrel has disappeared from most of its former range in Britain.
In the UK we welcome North American visitors with open arms – except perhaps for one: the grey squirrel. This charming-looking creature has a dark side. It has devastated our native population of red squirrels, hastened the disappearance of our native dormouse, and in some places has caused decline in songbird populations. It also causes untold damage to young hardwood trees such as oak, beech and ash. These little creatures are frustrating so many worthy efforts to re-establish native hardwood plantations, and they provide one more example of how our interference with natural systems can cause chaos.
I don’t suppose we will be able to do much about the grey squirrels, save controlling them locally when their numbers grow, but my heart sinks every time I hear of the latest big idea to introduce yet another new species of animal or insect from elsewhere in the world in order to deal with a problem caused by a previously imported species. And I am completely exasperated when such schemes from time to time are given the blessing of wildlife groups. Clearly even some of those who work closely with Nature, and who struggle so hard to protect her, sometimes think with the same mechanistic ideas that created the very problems they are trying to solve.
There is some good news, however. The Red Squirrel Survival Trust is for example, working hard to maintain and expand the populations of this wonderful creature. I have been pleased to help them with their effort to save these utterly charming creatures from what looks like imminent oblivion in these islands.
Elimination
While it is sometimes hard to comprehend the scale of the impact we have had on the Earth, the picture pieced together by the meticulous work of thousands of scientists tells an increasingly worrying story. Many in conservation circles believe that a sixth great extinction event is under way – a situation that might soon lead to a tsunami of species loss. This is not least because the rate at which species are being lost is now estimated to be between 100 and 1,000 times the natural background rate at which species disappear. Different kinds of animals and plants have always disappeared, but at the current high rates some projections suggest that by the end of this century we could lose up to 50 per cent of the total number of species that now inhabit the Earth.
Of course, during the long period that life has existed in abundance on Earth there have been times of rapid change. Indeed, etched into the fossil record are five periods when a large-scale loss of animal and plant species occurred – the last was when the dinosaurs disappeared, about 65 million years ago, marking a sharp boundary in the geological record between one epoch and another. Many believe the world recently entered a new one. And this one marks the fact that for the first time in the history of the Earth a single species has become the most dominant ecological agent – it is we humans, and that is why the period is called the Anthropocene. We are now the main reason for the rapid erosion of natural diversity, and whether we like it or not, this great living powerhouse is what sustains our well-being. We deplete and degrade it at our peril. In the pages that follow I will set out some of the reasons why this is the case, but for now it is enough to say that one reason why we are losing natural diversity so quickly is the rapid increase in our numbers.
Amphibian species are being lost at a terrifying rate. Fortunately the strawberry poison-dart frog remains common throughout its Central American range.
In 1900 the world population was about 1.6 billion. By the time I was born in 1948 it stood at 2.6 billion people. By the end of the twentieth century it had reached over six billion – marking a near fourfold increase in 100 years. In 2010 it will have exceeded 6.8 billion and is expected to continue climbing inexorably to about nine billion by 2050. While our numbers rise, and as we become richer and thus demand and expect more, the ability of our planet to meet our needs has significantly decreased. We are using up its natural capital and resources as if they were inexhaustible and without long-term value.
So far, as this has happened, food supply has managed to expand to keep up with demand. In part this has been achieved by ever more dependence upon intensive methods of farming, which we will explore later, and in part by the conversion of more and more land taken from Nature and put to agricultural use. Keeping pace with this demand has come at a terrible cost and unless we adopt some quite fundamental changes in expectation and practice, the cost is set to increase. Taking the world as a whole, in 1900 there were 7.91 hectares of land per person, whereas in 2002, owing to the increase in population and loss of land to urbanization, that figure had shrunk to 2.02 hectares. In 2050 it is expected that there will be about 1.63 hectares each – and from that ever smaller plot of land we will demand more and more.
Much of the world’s farmland is already virtually devoid of once native species of animals and plants, as modern high-tech agriculture has now basically turned farming into an arms race against Nature, excluding everything from the land except the highly bred crops designed to be resistant to powerful pesticides and grown using industrial production methods. These farming practices have a profound impact on the health – indeed existence – of the natural wildlife in the fields: the animals, plants, birds, the insects, microbes and bacteria that provide the services that sustain life. You don’t have to conduct major scientific studies to see that this is so. Watch the plough as it is pulled through the soil in the fields of many modern industrialized farms and notice how few birds follow the tractor. The great clouds of birds that were once the normal entourage of the plough were only ever there for the worms: and with fewer worms and other invertebrates in the soil, there are fewer birds. Some soils have lost their ability to restore fertility naturally and have become little more than a media for growth through the application of chemicals. The process not only continues but intensifies, with the use of ever more sophisticated chemicals and now genetic manipulation too.
The prairies of North America are a dramatic example. The land there was transformed in a very short time indeed and on a continental scale. Some 75 per cent of the United States’ original mixed-grass prairie has disappeared, much of it ploughed for the production of vast fields of maize, soya beans and wheat. This ‘thin-skinned’ land is now rendered at least temporarily productive with chemicals and machines, but in the opinion of many it should not be ploughed on such a scale. Its natural conditions render it vulnerable to collapse, which is what happened over large areas in the 1930s, when dustbowl conditions became one of the most potent images of the Great Depression. This situation arose through a combination of drought and ploughing; conditions that many believe could soon very easily be repeated – or exceeded – because of the effects of global warming.
LEFT: Soybean harvest, Brazil. Ever more intensive methods have increased yields. In 2010 Brazil and Argentina, the two biggest exporters after the US, increased soybean production by about a third. Industrial farming methods cause major environmental impacts, however, ranging from increased greenhouse gas emissions to largescale deforestation and from water pollution to biodiversity loss.
It was the excessive exploitation of the land, natural resources and animals of North America that caused Aldo Leopold to observe in his 1953 book Round River: ‘The outstanding scientific discovery of the twentieth century is not television or radio, but rather the complexity of the land organism. Only those who know the most about it can appreciate how little we know about it. The last word in ignorance is the man who says of an animal or plant: “What good is it?” If the land mechanism as a whole is good, then every part is good, whether we understand it or not … who but a fool would discard seemingly useless parts? To keep every cog and wheel is the first precaution of intelligent tinkering.’
Clearly European colonists did not understand the ‘land mechanism’ when it came to the prairies – or if they did they chose to ignore what they