Alien species

We are all too well aware of the damage that the arrival, by deliberate human action or not can and has done to the natural equilibrium of the British environment. Mink and grey squirrels are just two sad examples. [See Joanna’s April blog – Ed.] I thought a few lines on the disastrous impact of the introduction into Australia by European settlers, some of whom must have come from this part of Surrey, have had on the native wildlife. This was particularly so as the Australian continent had been isolated from the rest of the world for a very long time, to the extent that much animal life had evolved quite differently. I visit Australia every year or so to see my family and read about and encountered a little of their problems. As an example, to protect themselves from further problems, on arrival you are not allowed to bring in any vegetable product at all. Even a wooden ornament is barred. You have to declare that you do not live in or have visited any rural area recently. If you have you are sidelined at immigration for interrogation.

One introduction was of rabbits. Some early settlers, possibly to make it more like home released a few. They prospered and spread. They competed with native species for grazing. Worse, there were, despite the snakes and dingos, few native predators to keep them in check. Worse still, when one of Australia’s regular serious droughts came, the rabbits, unlike native grazers resorted to pulling out the roots of the grass, these are much more fleshy than normal English grass, so the when rain eventually came again the surface structure of the soil had been destroyed. No grass grew and what was grassland too easily became desert. All attempts to control them have failed. Remember the rabbit proof fence from north to south.

The immigrants also brought with them domestic dogs and cats. While these remain domestic and in towns they are not too much of a problem. But some escape and become feral. The immigrants also brought and released some foxes, so the they could have hunts, just like home. The native fauna, often trusting by nature, did not and still does not recognise these as dangerous predators and suffer accordingly. The Western Australian authorities put down a brand of poison in National park areas to control these feral interlopers to which native animals have natural immunity, and put up warning notices to any dog walkers.

A more recent deliberate introduction has been of cane toads from South America to Queensland to keep in check insects on the sugar cane, a major crop there. Unfortunately these toads did not eat the insects, but thrived on other native creatures. They too have prospered and spread across tropical northern Australia. Worse they carry a poison that will kill any potential predator. The last I read was that the authorities were relieved that they did appear to spread outside tropical areas. I hope and presume that they are trying to find a poison that will affect only these toads.

We may have our mink and our grey squirrels and many more, but they are not all in the same league as some of these.

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