They were once a common sight on summer days in the English countryside, but a new report out today says that Butterflies are finding it increasingly difficult to survive on Britain's farmland.

According to the research, carried out on behalf of Defra by Butterfly Conservation, numbers inhabiting farmland have declined by 30 percent over the last decade.

Biodiversity Minister, Jim Knight launched the report, saying: "Butterflies are an iconic species in their own right, and they can be good indicators of the health of the entire ecosystem, so this decline is worrying".

He added: "The implications for other insects, birds and mammals are concerning.

"The fact that this overall decline has taken place across the board means that we need to look very carefully at how we can help butterflies throughout the countryside, and particularly on SSSI's".

The study monitored trends for 40 Butterfly species across 820 sites, of which 371 were in agri-environment schemes - though since the monitoring was carried out agri-environment schemes have been replaced by the more widespread Environmental Stewardship schemes.

The study also identified that Butterflies declined at specific sites for a variety of reasons, including a lack of understanding of habitat requirements by land managers, overgrazing by rabbits, inappropriate bracken or scrub cutting regimes, and over- and under-grazing of farm animals.

Despite highlighting the acute problems faced by Butterflies, the report is confident that solutions can be found - especially through the encouragement of environmentally sensitive farming practices.

Mr Knight continued: "On sites covered by agri-environment schemes, we are seeing improved trends for six of the eight species listed as priorities under the Biodiversity Action Plan when compared to non-scheme sites.

"There were significant improvements for the Adonis Blue, High Brown Fritillary, Heath Fritillary and Silver-studded Blue, which thrive in short and medium turf conditions.

"However, species like the Small Blue and the Duke of Burgundy, which are associated with variable turf and scrub edge, aren't faring so well.

"These highly targeted agri-environment schemes may have been playing a positive role to significantly slow and even reverse the declines of these very threatened species, but there is still much work to be done to extend this trend to other butterfly species. We hope this can be advanced as more and more land comes under the new Environmental Stewardship scheme, which contains management options that should help butterflies".

Dr Tom Brereton, who spearheaded the research for Butterfly Conservation, said: "The results of the survey are worrying but we are optimistic about the new scheme.

"Real progress has been made in understanding butterfly declines and what to do about them".