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.
It is said that the Zulus started a war by drawing the Assegai out of the ground? I suggest draw a line in the sand and should not introduce any more species that do not currently live here and should be ultra vigilant to stop insects and other less visible intruders gaining a foothold.
I also suggest that those other non-natives that are the focus of argument now should be judged on the damage they do or do not do - eg grey squirrels damage trees and carry a pox which kills red squirrels - thus they should be controlled; mink kill water voles - thus they should be controlled and so on.
The fact is that a long time ago man's fingerprints were laid on our lands and it is our responsiblity to manage, having once interferred.
The option to let nature create the balance is foolhardy at best.
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?
Animal introductions have caused plenty of problems here and elsewhere in the World but perhaps mention could also be made of plant introductions - the dreaded Japanese Knotweed for example. I have seen some astonishing stands of this plant in the Swansea area in particular (though it's well established everywhere).
I don't know if the 1 in 10 ratio, referred to by Mark, holds for plants or not but there is a massive, legitimate trade in garden plants, mostly non-native, which seems likely to result in the ongoing releasing of new species into the wild at a slow but steady rate. Not to mention the various moths, worms, weevils etc that often hitch a ride with the plants when they are imported.
“The main problem is that the public do not like birds and mammals to be killed, rats and mice excepted. Witness Ruddy Ducks, and hedgehogs on the Uists. In contrast, destroying the habitats where birds and mammals live (by using biofuels for example) is seen as inevitable progress.”
• Agreed – but you’ve missed out TB in mammals – most people (RSPB members and staff included) do!
“It is difficult to see how a membership organisation like the RSPB can take the lead in calling for the elimination of invasive non-native species (except rats and mice of course) without losing members. That should be left to government agencies.”
• If the RSPB was managed by knowledgeable intelligent scientists instead of …….. then it would be achieving what you suggest – like a political party – the RSPB gets the membership it deserves – and it doesn’t always help the flora and fauna of the UK!
“As for introducing more stuff from mainland Europe because of climate change, have we learnt nothing from past mistakes?
• In my locality Axe Edge Moor is the major moorland west of Buxton in the Peak District - it is mainly gritstone with its highest point (551 metres (1,808 ft)
• The moor is the source of the River Dove, River Manifold, River Dane, River Wye and River Goyt. The moor is shared between the counties of Derbyshire, Staffordshire and Cheshire, which meet on its south-western flank at the Three Shire's Head on the Dane.
• A neighbouring farm’s well has just dried up for the first time in living memory – and other farmers with lots of cattle can’t move them because there is no (naturally available) water. At least this should please those RSPB members that are left-wing vegetarian loonies.
The main problem is that the public do not like birds and mammals to be killed, rats and mice excepted. Witness Ruddy Ducks, and hedgehogs on the Uists. In contrast, destroying the habitats where birds and mammals live (by using biofuels for example) is seen as inevitable progress.
It is difficult to see how a membership organisation like the RSPB can take the lead in calling for the elimination of invasive non-native species (except rats and mice of course) without losing members. That should be left to government agencies.
As for introducing more stuff from mainland Europe because of climate change, have we learnt nothing from past mistakes?
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