Here I may state the great principle which, in regard to plants as well as animals, determines the survival of intruders from one region to another. It appears that setting aside any very special and peculiar adaptations to quite exceptional conditions in a given area, the living things, whether plants or animals, which are brought to or naturally arrive at such an area, survive and supplant the indigenous plants and animals of that area, if they themselves are kinds (species) produced or formed in a larger or more variegated area; that is to say, formed under severer conditions of competition and of struggle with a larger variety of competitors, enemies and adverse circumstances in general. Thus, the plants of remote oceanic islands are destroyed, and their place and their food are taken by the more hardy "capable" plants of Continental origin. And, in accordance with the same principle, as Darwin especially maintained, the plants of the northern hemisphere, produced as they are in a wide stretching belt of land—Europe, temperate Asia, and North America—always push their way down the great southern stretches of land (by cool mountain roadways), and when they have arrived in the temperate regions of the southern hemisphere, they have at various geological epochs starved out, taken the place of, or literally "supplanted" the native southern flora, which in every case has been formed on a narrow, restricted and peninsula-like area. The same greater "potency" of the animals of the Holartic region has in the past established them as intruders into South America, Ethiopia and India, and has led to the inevitable survival of the animal of the large area when brought into contact with the animal of the small and restricted area. Applying these principles to New Zealand, we see that no country, no area of land, could have a worse chance for the survival of its animal and vegetable children than that mysterious land, isolated for many millions of years in the ocean, the home of the Tuatara, solitary survivor of an immensely remote geologic age, the undisturbed kingdom of huge birds, so easy-going that they have ceased to fly, and have even lost their wings!
The first European animals to settle there were the pigs benevolently introduced into New Zealand by Captain Cook. They multiplied apace, served for food and sport both to the natives and the early settlers, and destroyed the ancient Triassic reptile, the Tuatara, which only survives now on rocky islands near the coast. In less than a hundred years the settlers had introduced sheep and cattle, and looked upon the abounding pigs as a scourge. In 1862, pig-hunters were employed to destroy them—three hunters would kill 20,000 pigs in a year. Dogs, cats and the European rats came in early with the settlers, and destroyed the flightless birds, driving them for shelter to the mountains. As the settlers increased they shot down millions of birds of all kinds, and burnt up grass, shrub, and bush. At last, a few years ago, the Government established three islands as "sanctuaries," where many of the more interesting birds survive, and are increasing.
Besides cattle and sheep (which have flourished exceedingly) the colonists introduced rabbits, pheasants and the honey-bee, and later on quails, hares, deer, and trout. Clover depends on bees for its fertilisation and seeding. White clover, taken over there for pasture, did not seed in New Zealand until the honey-bee was imported in 1842, and later, as they could not seed red-clover without it, the colonists had to introduce the humble-bee, and the red-clover now also seeds freely and the imported farm-beasts have their accustomed food. Besides the animals already named, the colonists have introduced ferrets and weasels, to reduce the destructive excess of the imported rabbits; and they, whilst failing to subdue the rabbits, have themselves become a serious nuisance. Of small birds there were introduced the house-sparrow, which is too prolific, and is hated by the farmers; the greenfinch, a pest; the bullfinch, a failure. The introduced skylark and the blackbird (alas! poor colonists) are not the joy of New Zealanders—the farmers hate them. The European settlers had the audacity to introduce also the most beautiful and beloved of all birds, our own perfect "Robin Redbreast," and they add want of manners to their violent and uncalled-for hospitality by speaking ill of this sweetest and brightest of living things. After this, I am rather glad to report that the esteemed table-delicacies, pheasants and partridges, don't get on well in New Zealand; nor do turtle-doves. The thrush is spreading and meets with the approval of the hypercritical New Zealander. The hedge-sparrow, the chaffinch and the goldfinch have flourished abundantly, but the linnet has failed. A very interesting and important problem for New Zealand naturalists to solve is that as to why one bird succeeds in their remote land and another does not. The British trout have grown to an enormous size and are destroying all other fresh-water life. Imported red-deer flourish, and are shot with great satisfaction by the colonists. The American elk has been introduced in the South Island, and the mountain goats—the ibex and the thar—are to be acclimatized in the mountains, so that unnatural sport may flourish in this ancient land of quiet and of wondrous birds, turned topsy-turvy by enlightened man.
CHAPTER XXIV
THE EFFACEMENT OF NATURE BY MAN
Very few people have any idea of the extent to which man since his upgrowth in the late Tertiary period of the geologists—perhaps a million years ago—has actively modified the face of Nature, the vast herds of animals he has destroyed, the forests he has burnt up, the deserts he has produced, and the rivers he has polluted. It is, no doubt, true that changes proceeded, and are proceeding, in the form of the earth's face and in its climate without man having anything to say in the matter. Changes in climate and in the connections of islands and continents across great seas and oceans have gone on, and are going on, and in consequence endless kinds of animals and plants have been, some extinguished, some forced to migrate to new areas, many slowly modified in shape, size, and character, and abundantly produced. But over and above these slow irresistible changes there has been a vast destruction and defacement of the living world by the uncalculating reckless procedure of both savage and civilised man which is little short of appalling, and is all the more ghastly in that the results have been very rapidly brought about, that no compensatory production of new life, except that of man himself and his distorted "breeds" of domesticated animals, has accompanied the destruction of formerly flourishing creatures, and that, so far as we can see, if man continues to act in the reckless way which has characterised his behaviour hitherto, he will multiply to such an enormous extent that only a few kinds of animals and plants which serve him for food and fuel will be left on the face of the globe. It is not improbable that even these will eventually disappear, and man will be indeed monarch of all he surveys. He will have converted the gracious earth, once teeming with innumerable, incomparably beautiful varieties of life, into a desert—or, at best, a vast agricultural domain abandoned to the production of food-stuffs for the hungry millions which, like maggots consuming a carcase, or the irrepressible swarms of the locust, incessantly devour and multiply.
Another glacial period or an overwhelming catastrophe of cosmic origin may fortunately, at some distant epoch, check the blind process of destruction of natural things and the insane pullulation of humanity. But there are, it seems probable, many centuries of what would seem to the men of to-day deplorable ugliness and cramping pressure in store for posterity unless an unforeseen awakening of the human race to the inevitable results of its present recklessness should occur. Whatever may be the ultimate fate of the earth under man's operations, we should endeavour at this moment to delay, as far as possible, the hateful consummation looming ahead of us.
It is interesting to note a few instances of man's destructive action. Even in prehistoric times it is probable that man, by hunting the mammoth—the great hairy elephant—assisted in its extinction, if he did not actually bring it about. At a remote prehistoric period the horses of various kinds which abounded in North and South America rapidly and suddenly became extinct. It has been suggested, with some show of probability, that a previously unknown epidemic disease due to a parasitic organism—such as those which we now see ravaging the herds of South Africa—found its way to the American continent. And it is quite possible that this was brought from the other hemisphere by the first men who crossed the Pacific and populated North America.