Invading armies in the area - part 5
IN this mini-series, I haven’t yet mentioned reptiles, and that group contains a species which gives much cause for concern in Spain, namely the Florida galapago, aka American turtle, which has aggressively ousted its European counterpart, and taken over much of the freshwater habitat available in this country.
Breeding prolifically, these creatures may live for up to 40 years, achieving the dimensions of a dinner-plate, and one ill-effect of their presence is that they consume all the tadpoles and spawn of the local frogs. Local conservation groups try to fight against them, but it seems to be a losing battle.
There are, of course, other invaders that I haven’t mentioned.
From time to time, there are always ‘scares’ about big black cats or crocodiles, such as the ones that reputedly inhabit the New York sewers, and the subject of invasion is by no means one that is limited to Spain.
Britain’s little owls all originate from a nineteenth century introduction, and very much more seriously, rabbits have been introduced just about everywhere, so that Antarctica is the only continent on which they are not to be found.
In Australia, they have caused many millions of dollars’ worth of damage. New Zealand’s birdlife has been radically altered by introduced birds, rats, cats, and dogs, with flightless species, as on other islands, being wiped out completely. The national symbol, the kiwi, is now reduced to a few tiny islands offshore, where it is jealously protected, and the New Zealand avifauna has a distinctly familiar ring, with song thrushes, cirl buntings, and so forth, well to the fore.
House sparrows and starlings have found their way, probably on board ships, to the New World, and are common in much of the USA and Canada, as now are collared doves, which seem to have found their own way!
Cattle egrets too have spread into America, also, I think, naturally, and are now found in many parts of North and South America. The tiger mosquito I have already mentioned as a colonist too.
Rats and cats are a big threat to island populations, especially of nesting seabirds, and flightless birds – the dodo was a famous example from Mauritius. But we live in a world where invasion is all too easy – we just have to try to limit its effects.