RESPONSES TO SEVERE FIRES IN HEATHLAND MOSAICS IN SOUTHERN ENGLAND

We investigated the effects of uncontrolled fires in 1976 on II large heaths in Dorset, England, which were unmanaged over the period of stu dy. These heaths consisted of mosaics of heathland and associated semi -natural vegetation which we categorised into a number of vegetation t ypes. We compared the cover values and species compositions of these t ypes in burnt and unburnt zones in 1978 shortly after the fires and ag ain in 1987. The vegetation in the unburnt zones was stable between th e two surveys except for a loss of some dry heathland to scrub and woo dland invasion. The dry, humid and wet heathlands and peatland showed few responses to the fires and all effects were transitory. Some of th e scrub, woodland and carr vegetation was burnt out and the latter two vegetation types had not recovered by 1987. The scrub recolonised rap idly in the burnt zones but with a changed species composition. Bracke n showed slight increases after burning. The uncontrolled fires did no t seem to have the devastating effects on the heathland vegetation tha t might be expected. We discuss the reasons for this.