More than 8,000 conservationists and policy makers are in Barcelona, Spain, for the IUCN World Conservation Congress.

Held once every four years, the gathering is viewed as a landmark event where future conservation strategies are developed.
In his daily diary, environment correspondent Richard Black reports on the topics beings discussed in the conference halls, and visits some of the fringe events.
At least 25% of mammals, including the Caspian seal, are at risk
One is saying ""we've heard it all before""; another is asking ""so what?""
A third is contending ""I don't believe it"", while its less robust companion bewails ""there's nothing we can do"".
These voices are very familiar. They bug me every year when the Red List of Threatened Species comes out, and they were particularly prominent last year around the launch of the UN Environment Program's Global Environmental Outlook (Geo-4).
They are all saying things that in their own way are quite sensible.
We have heard it before -- the message of environmental doom is very familiar to anyone who reads further than Heat magazine and the immigrant-petrified middle tabloids.
The implications of biodiversity loss are nebulous next to a train crash, disaster seems hard to credit when our cat is well fed and the car works, and there probably is nothing that we can do.
So does that mean it is not worth hearing that 25% or 30% or 12% or 45% of one or other group of species is heading down the path to extinction?
If I was about to be hit over the head with a large stick, I would prefer to know.
If a quarter of the world's mammals are heading for the mortuary drawer, again, I would like to know, even though I might not have a clue how to stop it.
In fact, working out how to stop it is probably the hardest task facing the human race. Nuclear disarmament looks like a doddle by comparison, because the root causes of biodiversity loss are simply what our successful species does to live, eat, develop and expand.
Presumably we are going to keep doing those things. So presumably other life-forms, less adaptable, will feel a tighter and tighter squeeze.
""Haven't you always wanted the chance to live a sustainable lifestyle?
""Well now you can, thanks to the government's Sustain-a-bill!""
Unless I am mistaken, this is the future of advertising -- at least, as foreseen by a panel of luminaries connected with the industry who held a post-tea break discussion at the congress.
""The advertising and marketing services industry has in part been responsible for encouraging overconsumption,"" Sir Martin Sorrell, CEO of the marketing services group WPP, admitted in a pre-recorded video message.
""But we've but come to a stage where overconsumption is not necessarily the best route to follow, so responsible consumption is becoming increasingly important.""
He picked out events that he believed showed businesses were transforming their paradigms towards sustainability, such as Rupert Murdoch's espousal of carbon neutrality and Richard Branson's investment in low carbon energy.
Dean Sanders, a former Kraft executive who now runs the marketers GoodBrand and Co, argued that advertisers weren't responsible for advertising environmentally damaging products -- it was the fault of the companies that made those products.
And Cheryl Hicks from the World Business Council for Sustainable Development (WBCSD) suggested advertisers could help sell people on a sustainable, low carbon, environment friendly lifestyle, if governments would only engage them to do so.
So there we are. Advertising and marketing agencies, or at least this small sample, see themselves as part of the solution to the growth in consumption that lurks -- together with population growth -- behind every other environmental problem.
Having delegates fly in to international conferences isn't very smart when the conference has a strong environmental theme and aviation is widely seen as Public Carbon Enemy number one.
Messages about saving the planet do not mix well with talk of air miles and upgrades -- though the mix does happen.
OK, so most green groups offset these days -- but that's not a flawless process.
Hence the decision by the World Conservation Congress organizers to invite delegates to sail.
Blown by the wind, navigating by the stars, perhaps doing a little sustainable fishing on the way -- what better way to arrive ethically and climatically clean.
So the bright Catalonian morning saw perhaps 15 boats, maybe a few more, moored up in the dock before making the short hop to the conference center itself, where they would ""deliver their message"".
The message appeared to be that more awareness of issues like climate change, biodiversity loss and marine pollution would be a good thing -- which probably 99% of people in the conference center would agree with anyway.
---------------------- Stormy waters
There were some interesting vessels on display, ranging from the mighty research ship MarViva (which I mistook for a tug at first sight), complete with submersibles and an engine that racked up decibels with the abandon of Led Zeppelin, down to ordinary yachts.
One that caught my eye was the Tara, a futuristic metal-hulled research boat which has just spent 16 months drifting in the Arctic. Yes, drifting -- allowing itself to become enmeshed in ice when the ice built up -- although director Etienne Bourgois told me the ice turned out to be about half as thick as they were expecting.
Tara facts three and four: when ice converges on the boat it is lifted out of the water onto the floes, with no damage; and the crew spent 18 months seeing no-one but each other.
Then there was the Largyalo, a catamaran with giant canoes as the bits that go in the water (I believe they're still called hulls on a catamaran but don't quote me).
The inspiration was Polynesian, the boat's ""constructor"" Petra told me. It's sure to catch attention during its planned 1,000-day, 100-port trip raising awareness about climate change.
And that is really the point. The initiative was called Sailing to Barcelona, but delivering their message here will be as plain sailing as you can get - everyone wants to hear it.
The big world is a stormier place, where the worthiest messages get tossed around on angry seas, and sometimes wrecked before their time. (Source: BBC)