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A windswept hill farm in North Wales has been found to be a Mecca for spiders.
Researchers for the two-continent BioBio study discovered the Denbighshire farm harboured more species of spider than anywhere else they studied in Europe and Africa.
Some 1,442 spiders were collected on the 63ha livestock unit, spanning 82 species.
It is thought the farm is crawling with spiders because of its unique geography – it partly overlays limestone as well as the more typical, acidic rocks of upland Wales, increasing the number of spider- friendly vegetation types.
Welsh farms in general supported high numbers of spider species, said IBERS scientist Dr Peter Dennis, of Aberystwyth University.
He said: “Many but not all spiders require stiff, woody shrubs or tall herbs to anchor the webs. These tend to be found in hedgerows, unmanaged field corners, wetlands, water margins and on heath.
“In addition, wolf spiders pursue prey on shorter, grazed land, while money spiders form small, circular webs on the same pastures.
“The upland and hill farms of Wales typically have a larger number of these different habitats, combined with mild Atlantic weather conditions.”
The BioBio study, which probed 205 farms, was set up to assess differences in farmland biodiversity between organic and conventional systems.
It looked at four groups – plants, earthworms, spiders and bees – over a three-year period.
Aberystwyth University was part of the Swiss-led team which investigated 10 regions in Europe, and two in north and east Africa.
It found that organic techniques were less important than the number of different habitats each farm supported.
More species were found in organic arable fields, but there was little difference in grasslands or vineyards.
And while more plants and bees were found on organic farms, numbers of spiders and earthworms were the same.
But when field boundaries such as grass verges or hedges were included in comparisons, there was little difference between the two systems, suggesting diversity of habitats was the crucial factor.
Dr Dennis said: “More than organic farming is needed to sustain farmland biodiversity.
“Surprisingly, we did not find a higher number of different habitats on organic farms.”
In Wales, 20 livestock units in the hills and uplands were investigated, all with low to moderate intensity of management.
In individual fields, more species were found on organic holdings, but when biodiversity was assessed across the whole farm, few differences were observed.
One explanation is the richness of habitats on all farms in Wales. On average each farm had 12-15 different semi-natural habitats, placing Wales in the top three regions studied in Europe – the other two being Gascony in France and Bavaria in Germany.
The BioBio report concluded that targeted action for biodiversity is needed in both organic and conventional farming systems.
“It was clear-cut that the diversity of habitats is key to species diversity,” said Dr Dennis.
“We recommend that farmers increase the number of habitats, and we can discuss how that can be achieved with interested farmers.