Following a blog on reintroductions how about one on reintroductions' evil twin - introductions?
There is a general rule in biology that about one in 10 non-native translocated species becomes established in its new home - and that then one in 10 of those becomes an economic or conservation problem. Non-native species are one of the prime causes of species' extinction and so carting species around the globe is generally a bad thing (please note - Richard Branson).
Many of the non-native species in the UK were allegedly brought here by the Romans (eg pheasant, rabbit) but others were deliberately or accidentally released by the landed gentry (eg little owl, grey squirrel, muntjac deer and Canada goose). But then there is a long list of species whose origins are unknown but which are here as a result of careless trade across the globe.
This blog has commented on ring-necked parakeets (here, here, here and here), pheasants (here), muntjac deer (here) and grey squirrels (here, here and here) at various times to illustrate the practical and intellectual issues surrounding this subject.
It seems likely that we will face continuing and growing problems with non-native species becoming established in the UK. One of the latest arrivals is the scary creature the killer shrimp. What havoc might this species cause in our waterways? What happened to the New Zealand flatworm that was going to take over our gardens about 15 years ago?
Prevention is better than cure, and far cheaper, but difficult to police and ensure. I just have a feeling that this is a growing problem that we will all have to live with. It won't kill us - but it might finish off a few more native species if we aren't careful. And experience shows, we won't be careful enough.
the Global Invasive Species Database names the latest additions to our known invaders, at number one is a shrub, the fast-growing legume Acacia mearsnii. It is wanted for excessive water use and a negative attitude toward biodiversity, as well as a very aggressive tendency to extricate its neighbours.
Grey Squirrels interest me after having read two reports showing their negative effect on songbirds as negligable, becaus its such ingrained belief that they are so damaging. At what point do we start counting introduced species as accepted species? When does the ecology become irrecoverably adjusted to them that they stop being invasive, and instead become fundamental?
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