The destruction of natural habitats in Europe is wiping out butterfly, beetle and dragonfly species across the region, the updated European "Red List" of endangered species showed Tuesday.
Scientists examining Europe's 435 butterfly species found that the populations of one in three species are falling and nine percent are already threatened with extinction.
"Most butterflies at risk are confined to southern Europe," said Annabelle Cuttelod, coordinator of the European Red List at the International Union for the Conservation of Nature (IUCN).
Conservationists said a loss of habitats, including traditionally-farmed grasslands, woodlands and wetlands, was the major factor affecting insect species.
Nearly a third (31 per cent) of Europe's 435 butterfly species have declining populations, the report found.
Dr Martin Warren, author of the report on Europe's butterflies and chief executive of Butterfly Conservation in the UK, said insects were being hit by loss of grassland habitats due to both intensification of agriculture and abandonment of farming land.
While the large blue butterfly's reintroduction in the UK has proved a success, it is ''very much the exception'' as it is declining in every country where it occurs, Dr Warren said.
But conservation efforts to re-establish populations in this country after the butterfly vanished in 1979 showed what can be achieved if the right steps are taken, he said.
Dr Warren said most of the butterflies listed occurred on grassland or habitats which had been managed by humans and had benefited from traditional agricultural processes.
But now, he said, ''traditional systems are disappearing in a big way''.
''In the 1950s and 1960s we had massive losses of habitat in the UK, and it is still going on to a lesser extent, but in Europe big changes have been going on in the last five to 10 years.''
Intensification of agriculture is destroying habitat in some areas, while grasslands in many mountain regions in the Alps and Pyrenees are being abandoned and falling into a poor condition because livestock farming is not financially viable.
Dr Warren called for more support for traditional farming systems to help insects such as butterflies, which he said were very good indicators of changes to the environment.
For dragonflies, it is the depletion of freshwater resources that is causing these species to drop in numbers.
Five percent of dragonfly species are threatened with global extinction, while some 11 percent are considered to be near threatened within Europe.
"Increasingly hot and dry summers combined with intensified water extraction for drinking and irrigation are causing the dragonflies' wetland habitats to dry up," said the IUCN.
The list including some 6,000 European species is part of the IUCN's overall Red List, which is the most respected inventory of biodiversity covering more than 47,000 of the world's species.
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