Biodiversity

Essay 1: Biodiversity and Mr. Gradgrind

If someone were to ask you how many plants and animals are known to have become extinct since the year 1600, I wonder what you would answer. The general impression given by our media is that human development, including agriculture and hunting, has had a devastating effect on wildlife all round the world. In reality, the figure is tiny, being about 1030, of which 110 were mammals, 103 birds, and 396 higher plants (ferns and flowers). Even if we do not include viruses and bacteria, we have no accurate idea of the total number of species that might exist today. Estimates range from a low of 2 million to 14 million, and then upwards to a mind-boggling extreme of 80 million. To date, only 1.6 million of these have been physically counted and recognized. If we take the lowest of these estimates, it would still only give us an approximate extinction rate of 0.006 per cent every 50 years. Moreover, this low extinction rate must be offset by the evolution of new species (which we know is happening) and by the fact that species once believed to have been lost forever are being constantly re-discovered. In the Atlantic forests of Brazil, for example, a number of species thought to have become extinct 25 years ago, including six butterflies and several birds, have been re-found recently. And, with much publicity, the ivory-billed woodpecker (1), declared extinct in 1920, has just been spotted in the Big Woods of eastern Arkansas. So the corrected extinction rate will be much less – indeed, for all we know, it might even be negative. Now that is a thought – I bet that doesn’t get into the press!

Yet, for some time now, Green activists have wanted us to believe that we are losing in the order of 40,000 species every year, or 109 species a day. Former US Vice-President, Al Gore, repeated this figure in his book, Earth in the Balance(1992). Amazingly, however, even this hype has now been topped by the media response to a recently-published scientific paper which gave rise to sensational headlines, the broadsheets outdoing each other in their tabloid-like frenzy: “Over a million species will be doomed to extinction owing to the effects of global warming.”

But, as always, the devil is in the detail. It may thus come as a surprise to those of you who were shocked by such lurid headlines to learn that the original study, entirely valid within its own terms, was based on only 1,103 species that were selected from a number of regions around the world – 243 were South African members of a plant family called the Proteaceae, which has some 1,000 species in all. Using, in this instance, the widely-employed media estimate of 14 million species, this would mean that the research sampled 0.008 per cent of the total species on the planet. But, as I have already indicated, we have no idea of the validity of such an estimate. What the original research showed us is that, if the selected climate model were to be correct (an enormous caveat, of course), some 15 to 37 per cent of the 1,103 chosen species, in certain habitats, may be under threat. The rest is virtual extrapolation and speculation – and unfettered media hype. So we have moved, at the flick of a computer button, from around 400 species, or less, to 1.25 million extinct species and to ‘Apocalypse Now’.

Happily, you don’t have to be a scientist to see the flaws in all of this. Common sense is a mighty powerful tool when one is confronted by doomsday headlines. First, if you change the climate model employed, the outcome will be radically altered. There are hundreds of possible scenarios for future climates, and, if you do want to rid the ‘virtual’ Earth of millions of species at the click of a mouse, then try the ‘We-Are-Plunging-Back-Into-An-Ice-Age’ model. Your computer screen should then coldly display mammoth extinctions on a global scale. Secondly, if you adjust the range of plants and animals selected for study, you will likewise achieve a different outcome, and choosing the tiny beasties, from viruses to insects, might well give you an overall increase in biodiversity, certainly for some parts of the globe. 

Thirdly, as was most perceptively pointed out by the New York Times of all newspapers, this type of analysis is usually based on a number of steady-state assumptions, such as the ways animals might migrate and respond to climate change. Charles Darwin would have credited the organisms with more dynamic, adaptive nous. Fourthly, the whole approach tends to rest on a biological construct called the ‘species-area relationship’, which is not as robust a model as one might think when approaching the study of extinctions. This construct is used to argue that smaller habitat areas support fewer species. But, as a number of commentators have pointed out, there are many other factors involved. On the island of Puerto Rico, for example, a 99 per cent loss of primary forest cover did indeed cause the loss of 7 out of 60 species of bird, although the whole process of deforestation augmented the total bird numbers on the island to 97, thus increasing the overall biodiversity. Things are never simple. 

We should thus ensure that over-enthusiastic media extinction claims become as dead as the proverbial dodo.

(1) For more on the ivory-billed woodpecker, including its songs, go here: Cornell Lab of Ornithology.

[Partly adapted from an article first published in Country Illustratedin 2004]

Essay 2: Extinction and Mr. Thurber

Extinction is a natural process that has progressed since the very first organisms appeared in the primordial soup. Estimates are again difficult, but somewhere between 95% and 99.99% of all organisms that have ever existed have become extinct. Extinction is thus the norm. Moreover, the process is both gradual, as with the mean estimates given in Essay 1 above, and catastrophic. There have been at least five major catastrophic extinction events through geological time.Around 440 million years ago, at the end of a geological period called the Ordovician, when life was entirely marine, there was an enormous glaciation that killed off more than 60 per cent of the marine invertebrates existing at the time, including trilobites and reef-building fauna. This was followed at the end of the Devonian period (around 365 million years ago) by another glaciation that destroyed 70 per cent of marine life, such as jawless fish and, once again, those poor-old trilobites.

This was then topped, 225 million years ago, by the most dramatic of all mass extinctions, known as the Permian extinction. Huge volcanic eruptions – thought to be a million times more powerful than that recently recorded at Mt. Saint Helens – helped to destroy between 90 to 95 per cent of all marine life. 

Later, for reasons that are not entirely known, but which might have involved a comet shower hitting the earth, a further catastrophic extinction is recorded for the end of the Triassic period, 210 million years ago. Finally, this was followed, at the end of the Cretaceous period (65 million years ago), by the most famous of all mass extinctions, namely the demise of the dinosaurs. Although the cause of this iconic extinction event remains hotly debated, it may well have been triggered by a meteorite striking the earth in the Yucatan peninsula of modern-day Mexico.

So extinction is entirely to be expected; it is an integral part of an ever-changing earth. Moreover, extinction does not signal the end of life on earth, even in its most devastating and dramatic guise.

Further we must recognize that change is neither totally disadvantageous nor totally advantageous for all forms of life. Change, whether climatic change or some other form of geological or ecological change, will always benefit one set of organisms and regions at the expense of others. A limited warming, for example, would unquestionably benefit the overall biodiversity of the British Isles. To put it simply, we would have more moths, butterflies, and birds to watch. The hummingbird hawk-moth could grace our gardens throughout the year, rather than being largely a summer migrant to our shores, while our bird life would be enriched by spectacular newcomers, such as the bee-eater, the great white egret, the melodious warbler, the black kite, and the black-winged stilt. How the twitchers would twitter. What a tweet!

So what, in the end, can we say about our New Millennium ‘extinctions’ and ‘biodiversity’?  These appear to have little to do with the real world. They are largely ‘virtual’, as we trek intrepidly around our microchips to discover inside our computers, through mathematical models and modems, unknown, or lost, fauna and flora. Input a ‘tropical rain forest’, and you’ll notch up a million insects in the tree canopy at the click of a mouse (an also recently-evolved sub-species, some of which even inhabit houses). But these are only pixilated shadows, coleopterous and orthopterous statistics, totally beyond human hand or eye.

In the 1920s, in sharp contrast, James Grover Thurber, quondam humourist of the quirky New Yorker magazine, tells us about a certain Dr. Wesley L. Millmoss who used wire, papier mache, and similar materials to create his models of the ‘Middle Western Bestiary’, which included, among many others, the marriage-breaking Mound Dweller of Ohio, the Illinois Thake, and the Spotted, or Ringed, Queech, a lithe pussycat left over from the great Plasticine Ice Age. Sadly, all of his models were destroyed by fire in 1930. Today, even more alarmingly, we are told that 40,000 species are going extinct every year, or over a million in the next fifty years (take your gloomy pick), but only when you switch off your computer, or they are wiped out by nasty computer viruses (a splendid example of new ‘biodiversity’) bearing unlikely sounding names, such as ‘Melissa’ and ‘Bugbear’.

Yet, all these virtual creepy crawlies, and byting (sic) beasties, ‘die’ daily, often without a name, scientific or otherwise. James Thurber would have been distraught; just think of his white-faced rage next to a blind rage, and that unforgettable hoodwink on a spray of ragamuffin. As a child, I loved them. Life, and ‘Saving the Planet’, is simply no fun any more. There is nothing to make you laugh out raucously like Hackett’s gorm, one of the extinct animals of Bermuda, so perfectly encapsulated by Thurber as “a tailless extravertebrate about whom only one fact has survived the centuries: he was discovered by Mr. and Mrs. W. L. Hackett and their daughter Gloria.”

These days Gloria, or more likely Madison, would not be exploring Bermuda for lost gorms. She would be staring, gormlessly, at a flickering screen with lots of numbers and graphs, typing in oodles and oodles of data so that, at the press of a button, she might make them all become extinct. It’s a bit of a computer game really – Lara Croft to the rescue!

And then remember one vital, overarching point. If we closed down every factory, crushed every car and tractor, drove every farmer off the land, and shut down every power station, climate and the Earth would still change and there would still be extinctions as of old. It’s all hype and hooey (but beware the meteorite and the super volcano!).

[Partly adapted from an article first published in Country Illustrated in 2004]

Essay 3: Introductions and Miss Potter

The Tale of the Hebridean Hedgehogs
(with deep apologies to Beatrix Potter) 
ONCE upon a time there were four little hedgehogs who went to live on a Scottish island called South Uist. They were good little hedgehogs and they only ate beetles and slugs – but they did breed so. Soon there were too many to count on one foot.

One day, the more adventurous hedgehogs set out across the island to see what they could see. They met a Tabby Kitten, who was washing her white paws. “Tabby Kitten, do you know where there are birds’ eggs to eat?” “Meow!” said the Tabby Kitten, still washing her paws. “You should go to Benbecula.”

So they sailed across the tiny sea to see what they could see. There they met a speckled hen. “Sally Henny-penny, do you know where there are birds’ eggs to eat?” “Cluck!” said the speckled hen. “You should go to North Uist. But please don’t eat my eggs.”

So again they sailed across the tiny sea to see what they could see. There they met Cock Robin, sitting on a twig. “Cock Robin, do you know where there are birds’ eggs to eat?” “Tseee!” said Cock Robin. “You should go to the seashore. But please don’t eat my eggs.”

So off they set once more down to the grassy shore, moving as fast as their stubby legs would carry them. There they saw some white things spread out upon the grass and sand looking just like pebbles dropped from the sky. Soon they were cracking and crunching, sucking and slibbeling, with eggs for breakfast, eggs for luncheon, and eggs for tea.

But the poor birds waded about in the water looking all feathered and downcast, screeching at the PRICKLES in the grass and piping a sad song:

“Lily-white and clean, oh!
Our eggs must be saved, oh!
Hedgehogs on this sandy spot
Never here be seen, oh!”

The hedgehogs became twitchy, because lots of big people, like Old Mr McGregor, heard the birds’ mournful piping. They came to carry off the hedgehogs and they put them in small sacks, as if they were pocket handkerchiefs. Sometimes the spikes stuck out like hair-pins!

But other big people – those who like Peter Rabbit, Benjamin Bunny, Squirrel Nutkin, and all the other pests that eat lettuces or eggs – became very angry. They wanted to save the hedgehogs, prickle by prickle, and take them back to the old country where they could eat nasty things like slugs and snails, about which they did not care so much.

But little did they know. The hedgehogs were soon climbing, climbing, climbing up into the trees to find more eggs – for, after all, they were HEDGEHOGS.

Motto: Treat animals as animals, not as cuddly bunnies with no prickles…or teeth. 

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