Resistance of Atlantic Heathlands to trampling in Brittany (France): influence of vegetation type, season and weather conditions

As a result of the large increase in tourist pressure, trampling has become an important factor in the degradation of natural areas and particularly A tlantic Heathlands. In this study, the resistance of dry and mesophilous he athlands was studied experimentally, under different environmental conditio ns. The trampling was applied in winter, and in summer in periods of wet an d dry weather. The types of heathlands studied appeared to be moderately re sistant to trampling. Mesophilous heathlands were on the whole more sensiti ve to trampling than dry heathlands. The resistance of these communities an d of their component species varied greatly in relation to season and weath er conditions. For example, Erica ciliaris was more resistant to trampling in summer than in winter, and in summer Erica cinerea was more sensitive to trampling in wet weather than in dry conditions. The analysis of the resis tance of species showed that heather species were more sensitive than the r est of the plant cover. These heathers are characteristic species of the he athlands that were studied. The definition of acceptable visitor pressure t hresholds must not be based on the index of resistance of the whole communi ty, but on that of the characteristic species, in this case heathers. The a im of visitor pressure management must be to preserve the vegetation struct ure and not just simply plant cover. (C) 2000 Elsevier Science Ltd. All rig hts reserved.