The growing evidence linking green spaces to human wellbeing could help strengthen the case for conservation, a conference has been told.
Professor Ken Norris from Reading University said green spaces improved wellbeing, so that meant "they can also be linked to our health".
Ecologists need to do better when it comes to convincing people about the importance of conservation, he added.
He made his comments at the British Ecological Society's annual meeting.
Prof Norris, a co-author of the UK National Ecosystem Assessment, said it was sometimes necessary for scientists to closely scrutinise their own work.
"It is very rare that we ask ourselves some very hard questions in the first place, such as 'why the hell are we doing this in the first place?'," he told the audience.
Making the link
He argued that there was a need to strengthen the arguments used by ecologists to justify the importance of the work they did.
He explained that he favoured a framework that embraced the "ecosystem services" concept, which places a value on ecosystem functions - such as reducing pollution or cleaning water - based on what the economic cost would be if we degraded an area's biodiversity.
"We know that these things are linked to our wellbeing, so that means that they can also be linked to our health," Prof Norris observed.
Another speaker, Dave Stone from Natural England, highlighted that connections between the environment and human health were appearing in a number of high level policy documents, such as the Natural Environment White Paper.
But he asked whether, at a population level rather than an individual level, functional ecosystems and biodiversity were important for health.
Focusing on urban environments, as more than 50% of humans on the planet now lived in towns or cities, he said two key issues were air quality and excess heat.
"Most people are well aware that both air quality and excess heat have implications for public health," Dr Stone said.
Listing official figures, he said that 20,000 deaths in the EU were attributed to ground level ozone pollution, and excess heat during France's 2003 drought claimed 15,000 lives.
He asked: "Those effects are very real and costs thousands of lives, so what is the role of potential ecosystem services?"
Just looking at what he called "intra-urban" ecosystem services, he said it was known that city trees and shrubs reduced particulate concentrations and "vegetated urban areas experienced lowers temperatures".
The co-ordinator of the presentations at the three-day BES meeting in Birmingham, Dr Becca Lovell from the European Centre for Environment and Human Health (ECEHH), said there were a number of reasons for bringing together an array of speakers on the issue.
"There is a lot of research that is linked to green spaces in general and people's health," she told BBC News.
"But what we don't know what type of green space this is; whether it is a golf course, forest or coastal area etc.
"We also don't know about the state of that green space; whether it is degraded or whether it is very high quality with a lot of biodiversity, and whether that is important for people's health and wellbeing."
While there were some examples of GPs prescribing walks etc, Dr Lovell explained that there was a need for more robust and widespread data in order for the issue to be embraced.
"Although it is a low cost intervention and can have some good outcomes, I do not think the strength of evidence is there yet to justify it to the medical community, which needs very strong evidence showing cost/benefits."
A project by Manchester Metropolitan and Chester universities analysed citations of published evidence on biodiversity and human health.
It found that over the past 40 years, 173 articles had been published in 104 different journals.
"We asked whose discipline is it," explained co-author Dr Konstantinos Tzoulas from Manchester Metropolitan University.
"Is it ecologists who are looking to go into the health sector, or is it the health sector that is looking to go into ecology?
"That is why we carried out this study," He told BBC News. "Who is producing evidence and who is reading it?"
The team found that the issue was being researched by at least 30 scientific disciplines, including health, psychology, architecture, forestry and ecology.
As a result, Dr Tzoulas observed, the results indicated that knowledge was diffusing between the disciplines.
Dr Lovell concluded: "There is definitely interest at the higher level and going into policy. The evidence is there but not quite at a level to convince a lot of clinically minded people."