The accidental or deliberate movement of plants or animals around the world by man has been responsible for the global extinction of many species.
The British countryside hasn't escaped as many species from overseas are now on the rampage creating havoc for wildlife and their habitats. And the news today suggests that our ponds are in the front line of this battle.
Today's launch of the Be Plant Wise campaign, with the support of celebrity gardener Charlie Dimmock, is a welcome start in the control of the non-native pond plants that are choking many wetlands, including several notable RSPB reserves across the UK.
One of the worst offenders is the innocuous-sounding New Zealand pigmyweed, which has escaped from the confines of garden ponds and is now affecting many sites across the UK, altering the environment of wetlands and excluding native plants. Individually, the plants may be pigmies, but en masse these, and other non-native plants, are creating yet another conservation headache we have to deal with while managing over 200 nature reserves for birds and other wildlife.
The main aim of the campaign, which has received widespread press attention, is to urge gardeners to be careful when disposing of these plants or when clearing out ponds.
There are some dishes I couldn't even contemplate eating without seasoning - who would want egg and soldiers without a sprinkle of salt on the runny yolk for example? Ooooh I'm salivating at the thought...
But salt could kill some garden birds and the RSPB is urging people not to use it as a de-icer in bird baths as the weather gets chilly again.
Salt is toxic to garden birds, even in tiny amounts, as their bodies can't process it and it affects their nervous systems. If they ingest salt they get very dehydrated and thirsty which simply makes them take in more, potentially making the problem worse. Salt also causes kidney disfunction so its imperative that we leave it out of our feeding efforts.
Keeping bird baths unfrozen in this sort of weather could be a full-time job and try as you might you can almost guarantee that when you nip outside in the morning in your dressing gown to check it will be solid! There is no scientific answer to this and when temperatures really plummet is a case of patience! But you can take measures to keep the water moving for as long as possible, such as placing a small floating item like a cork or twig in it. Alternatively, when you do fill your bath, try using tepid water to keep it unfrozen that bit longer.
Please also avoid food that contains lots of salt. Salted crisps and peanuts, processed cheese and leftover frozen meals are all likely to contain dangerous levels , even if soaked. More suitable leftovers include garted mild cheese, porridge oats, cooked rice, unslated bacon, cooked potatoes and pastry.
Farmland birds have not had the smoothest ride in recent decades. Populations of skylarks, yellowhammers, lapwings and grey partridges have all been declining for several years.
But the fight back may be starting in a tiny far flung corner of the country where a small brown and yellow bird is clawing its way back from the brink.
The diminutive cirl bunting has hit the headlines in the Guardian, the Telegraph and on the BBC this week after a survey showed its number have increased by 25 per cent since 2003.
Now that may sound like a lot but in fact there are still just 862 breeding pairs, and they are restricted to small strips of Devon and Cornwall. If you live anywhere else then your chances of seeing them darting from a hedgerow on country walk are pretty miniscule I’m afraid. In fact despite their recent success they still enjoy the dubious honour of being Britain’s rarest farmland bird.
I travelled down to the Devon coast to our reserve at Labrador Bay which is a haven for cirl buntings not too long ago. It’s a spectacular place if you’re ever in that part of the country. And while they may be a little tricky to identify they are friendly creatures and will reward a patient birdwatcher.
Whilst there I met a nearby farmer who is doing lots of work on his land to provide a habitat for the birds. He was delighted to be doing his bit to save a species that once clung precariously onto survival in the UK by a thread. It is part of the job of a farmer, he told me, to look after the countryside and everything in it.
I went away with a renewed sense of optimism. If we can achieve this kind of success with a bird as close to the edge as the cirl bunting, then surely with dedication and hard work conservationists and farmers working together can halt the declines in our beleaguered farmland bird species across the UK.