BARCELONA, Spain - Worsening damage to nature is jolting the world into doing more to protect animals and plants and new economic arguments will bolster the case for action, the head of a global conservation network said.

Logging debris covers an area that was clear cut by a timber company on private land in the Umpqua National Forest near Drain, Oregon May 15, 2008. (REUTERS/Richard Clement) "We are really in trouble," Julia Marton-Lefevre, head of the International Union for Conservation of Nature (IUCN), told Reuters on Wednesday after an IUCN "Red List" this week showed that a quarter of all mammals were threatened with extinction.

"The amount of loss we have been able to measure ... is really pretty frightening," she said during an Oct 5-14 IUCN congress, held once every four years, during which 8,000 delegates are looking for better ways to safeguard the planet.

The IUCN groups governments, conservation organizations and scientists.

"People really get it that we have less water, that the water we have is not usable, that we have fewer places to breathe. People are noticing that the environment we have been taking for granted all of a sudden is not really there or there in a smaller way," Marton-Lefevre said.

She said the Barcelona congress showed conservation was "no longer a sideshow." The meeting is drawing government ministers, leaders of businesses such as oil group Shell and miner Rio Tinto, and indigenous peoples from the Amazon.

The mood was "there's enough conviction now that there is a problem and we do have some solutions so let's get on with it," she said.

But economic arguments about the essential role of biodiversity -- for uses such as food, pharmaceuticals or building materials -- had not yet sunk in fully.

"Maybe the economic message hasn't yet been made clear to people. Once they start counting, I think they'll see it pretty clearly," she said.

A report submitted to a U.N. biodiversity conference in May said mankind was causing 50 billion euros ($68 billion) of damage to the planet's land areas every year, with factors including pollution and deforestation.

High food prices highlighted the effect of loss of biodiversity, it said. The cumulative loss could amount to at least 7 percent of annual consumption by 2050, it said.

That meant conservation was a huge long-term challenge even if financial turmoil was now overshadowing threats to nature.

Marton-Lefevre said conservation was increasingly trying to "join the dots. It's not just the one species that you are in love with that the world is losing, but 'what does this mean?'.

She said the IUCN could help to offer solutions. "We have the instruments to protect some parts of the environment, protected areas or better species protection."

Some species have been brought back from the brink of extinction, for instance with captive breeding.