CONSERVATION OF ENVIRONMENTAL SPECIES
More on the prehistoric massacres
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In the previous issue we talked about what is the most investigated case of prehistoric massacre, that of the Clovis. Let's now look at some other cases, in different areas of the globe. The hypothesis of the extinction of large mammals by man was already advanced by Charles Darwin and Charles Lyell, in the second half of the nineteenth century; Paul S. Martin in the sixties of the following century deepens the search for clues, and examines the problem in a global key: everywhere he finds confirmation.
The counts carried out reveal that 73 percent of the genera of large mammals became extinct in North America; in South America, 79 per cent; in Australia, 86 percent; in Africa, only 14 per cent. In Europe there are intermediate percentages, and among others the mammoth, the mastodon, the woolly rhinoceros, the cave bear, the giant deer, the "tiger" with scimitar teeth disappear
Europeans of some time ago
On the side, the European with the largest horns; it is Cervus megaceros, and the horns are record-breaking: three meters wide. Perhaps they were a hindrance, when he began to evade the attentions of the first European Sapiens, and so he disappeared, much like the woolly rhino below, which was common for example in the south of France.
Asia has not yet been thoroughly investigated; for now it seems to present a picture similar to that of Europe. In Australia, extinctions occurred approximately between 50,000 and 40,000 years ago, with the arrival of the first populations of aborigines from Southeast Asia; the habit of the aborigines of setting fire to vegetation, together with hunting, explains the very high percentage of extinctions that occur on the continent, essentially to the detriment of marsupial mammals. A little later (starting about 40,000 years ago) there are the European extinctions, perhaps in phase with the replacement of the Neanderthals by Sapiens. In three island areas where man arrives very late, extinctions are correspondingly recent. Let's see them.
Opposite, but very distant and different
In Africa that is right there in front, man and his hominid ancestors have been there since the beginning, at least for four million years. But strangely enough, they arrived in Madagascar only around the sixth century after Christ; there they found a different and extraordinary world, where evolution had acted separately for millions of years. That world didn't hold out for long to the new predator.
In Madagascar the first humans are seen about 1500 years ago. The extinction of the fauna of that island begins soon after, and in 500 years the list of extinctions is almost complete: out of seventeen genera of lemurs, only ten survive up to a thousand years ago.
Madagascar's loss count is still ongoing, but the landscape is no different from that of other areas of the planet.
In New Zealand the first population of Polynesians arrived about 1000 years ago, and found a strange fauna, in which large flightless birds abound. This is a common feature of islands where there are no predators: birds arrive there, as they grow larger, and give up flight; obviously flying is often a defensive strategy for birds, which in the absence of predators becomes useless. The first Europeans to arrive in New Zealand do not have time to see the moa, large birds up to three meters high and weighing more than 200 kilos; the last ones disappeared between the fifteenth and eighteenth centuries; in total more than twenty species. On the island that represents the southern half of New Zealand, the Maori civilization, which derives from those early Polynesians, first destroyed the forests that covered the island (and the fauna that inhabited them) by fire. Soil erosion resulting from deforestation created a degraded environment. Excessive hunting of large birds and seals did the rest: the Maori civilization disappeared from Southern New Zealand long before Europeans arrived there.
Great roasts, on the islands!
On the side, the reconstruction of a moa, which today would be the ideal farmed chicken, if the first New Zealanders had not extinguished it. In fact, it has no wings and a large fleshy body, which by weight exceeds many calves of our herds.
Below, a dodo; this too was a very large bird, had succulent meat and did not fly. He lived quite well in Mauritius, until the islands were overtaken by dangerous predators: Portuguese sailors began calling there on their voyages to the east. Like the Polynesians, the Portuguese were also not vegetarians, and so the dodo died out in a roast scent
The count of large birds missing for centuries is ongoing in New Zealand and has already reached 35 species. Hunting, as always, is suspected, but it is known that on those two islands south of Australia the fire did its part: it was used intensively to clear the land and make way for crops; while he "cleared" the ground, he also roasted some large turkey.
In the Hawaiian Islands the panorama is even clearer: intensive studies have been carried out there over the last twenty years. The first men arrived in Hawaii in the fourth or fifth century, perhaps from the Marquesas Islands; they were therefore Polynesians, and they brought both plants and animals with them. They are believed to have introduced chickens, dogs, pigs, and sadly also the rat. Some of the imported animals did not cause problems for the local flora and fauna, but pigs, dogs and especially rats had a disastrous effect on the native fauna of the islands.
The human population remained low for a few centuries, then began to grow, so much so that in 1600 it approached (according to some estimates) one million people, more than the islands could maintain.
This involved dedicating all the land to agriculture, and the original vegetation was almost completely replaced by cultivated plants. When Captain James Cook "discovered" the islands for Europeans in 1778, his ship brought with it a lot of microorganisms against which the islanders had no immunity: tuberculosis, measles, flu, syphilis, and others. Due to those microbes, within a century the population of the islands has more than decimated, reduced to less than 50,000 people; the crops of the previous century are abandoned, and the fields become wild again. In that situation of degradation the Europeans intervene, and the destruction of what little remains of the original life of the islands is almost completed. In Hawaii until the 1980s it was thought that the destruction of the original species had begun with the arrival of Europeans, and locals were proud of the supposed ecological habits of their ancestors.
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