Image caption Almost 2,000 schools registered for Opal resources during the five-year project

The interim findings of a massive five-year citizen science project, involving more than 25,000 surveys and 500,000 people, have been published.

The Open Air Laboratories (Opal) project was designed to get people outdoors and provide a chance to get involved in scientific research.

The project also found that domestic gardens were home to the greatest number and diversity of earthworms.

Organisers are hopeful of securing funding to continue with the project.

"When we started off, we were really concerned about the lack of opportunities for the person in the street to play an active role in environmental protection," said Linda Davies, Opal director.

"We also realised that huge sectors of society were not involved or didn't really feel any affinity towards the environment."

She added that global agreements, such as the Convention on Biological Diversity, called for nations to document all of their flora and fauna.

"So we thought that there were so many things for people who wanted to engage to participate in," Dr Davies told BBC News.

'Very valuable'

Since its launch in 2007, more than 25,000 sites - ranging from street trees and hedges, allotments and woodlands, and parks and playfields - have been examined and data submitted to the project's database.

Dr Davies said the team behind the project plans to make all the information publicly available.

"There is a huge amount of information that [scientists] can use - it is very valuable long-term data," she explained.

"Some will identify trends, which we can then go on to investigate a lot further, while other show interesting things right from the start of the survey.

Image caption Project organisers were surprised by the number of people that wanted to be involved in the surveys

"For example, collection of pond sediment has never been done before so we did not know the sort of metal concentrations you would find in those environments."

One highlight, she revealed, was that private gardens were a biological hotspot when it came to earthworms.

"We certainly did not expect to see the highest number of earthworms (in terms of diversity) in back gardens."

Dr Davies was reluctant to expand too much on the project's findings because she said much of the data was still be analysed by scientists but said that they planned to published a detailed report in the spring and release information on the project's website.

She also added that data collection was just one of a number of objectives: "The first objective was just to get people out and enjoying the outdoors."

Another highlight of the project, which received £14m of lottery funding, was the development of software that provided people with the information needed to take part in surveys, as well as the means to submit their findings - the most successful being the iSpot application for smartphones.

"Uploading photos from mobile phones has been proven to be good enough to confirm identification of numerous species - many more that we first envisaged.

"Many natural history societies have been able to take the photos from iSpot as actual records to add to the national dataset of findings across the country."

High confidence

The organisers also addressed the concern that data collected by citizen scientists would not be as robust as information gathered by professional researchers.

Image caption Organisers hope the project will have a lasting effect, encouraging more people to enjoy the outdoors

"It is important that from the outset that we design it with scientists so then we can use the data that comes out of it," explained Dr Davies, an urban ecologist from Imperial College.

"[This touches] upon the most important issue for policymakers - can they rely on the data from the public when they are making decisions.

"If you ask people to count the number of earthworms then the confidence level is high.

"If you ask people to identify the earthworm species then that confidence level will fall, but you can account for that in the project design and the analysis of the data."

Although the project had formally ended, she said that organisers were hopeful Opal's work would continue.

"We hope this might inspire others to think about a national monitoring programme that the public could be involved with.

"We think there is far too much out there to shut up shop and walk away now, so we have got to find the means to carry on."