More than 100 countries pledged on Wednesday to put the protection of habitats at the heart of their government decision-making but they stopped short of committing to specific targets to curb mass extinctions.

Chinese Environment Minister Huang Runqiu told delegates to a U.N. Biodiversity Conference in the city of Kunming that the declaration they adopted was a document of political will not a binding international agreement.

The Kunming Declaration calls for "urgent and integrated action" to reflect biodiversity considerations in all sectors of the global economy but crucial issues - like funding conservation in poorer countries and committing to biodiversity-friendly supply chains - have been left to discuss later.

With plant and animal species loss now at the fastest rate in 10 million years, politicians, scientists and experts have been trying to lay the groundwork for a new pact on saving biodiversity.

In a previous agreement signed in Aichi, Japan, in 2010, governments agreed on 20 targets to try to slow biodiversity loss and protect habitats by 2020, but none of those targets was met.

At the heart of efforts to save nature is a call by the United Nations for countries to protect and conserve 30% of their territory by 2030 - a target known as '30 by 30,' which the conference acknowledged though it was not clear to what extent host China backed it.

"The declaration made a reference to the '30 by 30' target, but did not indicate if Beijing is on board with it or not," said Li Shuo, senior climate adviser with environment group Greenpeace.

A 30% pledge could prove too much for land-stressed China, which has nearly 10,000 nature reserves covering 18% of its territory.

"There are academics who say they think 24%, 25% might be reasonable, but even getting to the 18% was challenging, so 30% might be difficult," said Alice Hughes, a conservation biologist attending the talks on behalf of the Beijing-based China Biodiversity Conservation and Green Development Foundation.

A one-size fits-all target would also be inappropriate for countries like Indonesia and Brazil, where a 30% goal would actually allow more deforestation, she added.

Elizabeth Mrema, executive secretary of the U.N. Convention on Biological Diversity, played down the importance of the adoption of the specific 30% target.

"We need to keep in mind that we must focus on biodiversity outcomes rather than spatial area," she told Reuters.

'TOO SLOW'

Apart from the question of targets for conservation, some activists have complained that disagreement over the wording of the declaration had diverted delegates' attention when urgent action was needed.

A first draft of the declaration, released in August, included political slogans associated with Chinese President Xi Jinping, which caused tension and underlined what some critics said was China's inexperience in shepherding international agreements through to conclusion.

After feedback from more than 40 countries, Xi's slogan "lucid waters and lush mountains" was removed from the text, though the Chinese concept of "ecological civilisation" was retained.

There were complaints, particularly from Japan, that China had pushed the declaration through without sufficient discussion, sources familiar with the situation told Reuters.

"Basically they felt that there had been insufficient time for consultation on some of the declarations," said Hughes.

Huang told delegates that China had followed the same procedures used to adopt previous biodiversity agreements.

However, Li said it remained to be seen whether China had the experience to drive through a new pact during a second phase of talks next year.

"Our global biodiversity crisis is urgent but so far the Convention on Biological Diversity's progress has been too slow," he said.