Biologisk mångfald i Linnés hembygd i Småland. 7. Blomflugor (Diptera, Syrphidae).

• Hoverflies are important pollinators, but constitute a less studied group of insects. In this study we collected hoverflies in most open grasslands and woodlands in an area of 5000 hectares over six years (2004-2009) in the central part of the parish of Stenbrohult, southern Sweden (Fig. 1; 56o 37´ N, 14o 11´ E). The studied area is dominated by spruce forests, but deciduous forests are relatively abundant. Grasslands, mainly grazed by cattle and horses, cover about 6 % of the area. We sampled 20 subareas/farms dominated by grasslands, surrounded by forests and/or lakes. Mires and unpolluted wetlands are common in the study area, and the large Lake Möckeln in the west is unregulated. Parts of four farms are protected as nature reserves and more reserves are planned for other farms in the area. Hoverflies were surveyed by 6-8 annual visits to each subarea. The visits were evenly spread over the period from the middle of May to the middle of August, covering the open grasslands. On most farms additional visits were made, also in April and September, and one farm(Djäknabygd) was visited almost weekly from May to August each year from 2004 to 2012. In total we found 225 hoverfly species (Appendix). On the most thoroughly surveyed farm Djäknabygd 198 species were recorded on an area of about 17 hectares, as far as we know the highest species richness documented in Europe in such a small area. There was a high variation of species richness between the other farms, varying from 74 to 140. The highest number of species was found on farms in the central and western parts of the study-area, where old deciduous trees are most common and traditionally managed (harvest in late summer) and unfertilized hay-meadows still exists. Remarkable findings were among others; Brachyopa bicolor, Brachyopa panzeri, Callicera aenea, Callicera aurata, Chalcosyrphus piger, Chalcosyrphus valgus, Ferdinandea ruficornis, Hammerschmidtia ferruginea,Pocota personata, Temnostoma apiforme and Xylota meigeniana which all are of European conservation concern. We discuss the hoverfly fauna from a nature conservation point of view, and give details about habitat, phenology and flower use for the less common species.

Ämnesord

NATURVETENSKAP  -- Biologi -- Ekologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Ecology (hsv//eng)

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