CHANGING GRASSLAND UTILIZATION IN THE UNITED-KINGDOM AND ITS IMPLICATIONS FOR POLLEN PRODUCTION AND HAY-FEVER

Grasses form the most important source of airborne pollen in the Unite d Kingdom. This article reviews the ecological, geographical and histo rical features of grassland utilization relevant to pollen production. During the past half century extensive agricultural management, with botanically diverse swards and late (post anthesis) mowing for hay, ha s been progressively replaced by more intensive management with more r eliance on Lolium perenne and early mowing for silage. The role of Dac tylis glomerata and Phleum pratense has declined. A decrease in the Ju ne pollen catch supports the hypothesis that these changes have affect ed the quantities of pollen released. Incidence of hay fever shows geo graphical variation with climate, topography and vegetation type. Rece nt policy changes intended to decrease agricultural production and to meet environmental objectives may, in future, further affect the types and quantities of pollen produced.