Impacts of deer herbivory on ground vegetation at Wytham Woods, central England

Between 1974 and 1992 there were declines in bramble (Rubus fruticosus agg. ) and several woodland forbs and an increase in grasses at Wytham Woods. Th ese changes have been explained as effects of increasing deer populations. We set out to test this by establishing exclosure experiments in the summer of 1997. Comparison of permanent vegetation monitoring plots inside and ou tside the exclosures, showed that forbs tended to increase inside exclosure s whilst decreasing in the wider wood, supporting the hypothesis that deer herbivory was responsible for the change. Changes in individual species wer e not, however, significant and it may take many years for the vegetation i n the exclosures to reach a new equilibrium. In contrast to exclosures unde r the woodland canopy, additional exclosures in a clearing have been rapidl y colonized by bramble. It appears there is an interaction between solar ra diation and herbivory and the decline of bramble at Wytham may reflect cano py closure as well as deer herbivory. Faecal pellet counts made in Environm ental Change Network monitoring plots between August 1998 and April 1999 in dicated different habitat use by fallow (Dama dama) and muntjac (Muntiacus reevesi) deer. Grasslands in proximity to the woodland tended to accumulate proportionally more fallow deer faeces, whilst dense ancient woodland area s tended to accumulate more muntjac faeces. There was, however, little evid ence of an association between particular species of plant and differential habitat use by deer.