Secondary succession of semi-arid Mediterranean old-fields in south-eastern Spain: insights for conservation and restoration of degraded lands

A 60-year chronosequence study of semi-arid old-fields indicates that abandonment age, litter depth, organic carbon soil content, carbonate content and soil moisture are related to vegetation ordination. The species turnover could be high in the recent abandoned fields. Species richness varies, holding a non-linear relation with time as a result of the coexistence of different functional groups. Land use history determines the ordination of communities and previous cropping influences the pathway of succession. Plant functional group and dispersal type richness and cover show significant differences between old-field age groups. The facilitation pathway of crop trees on bird-dispersed shrub species could promote the development of vegetation under these stressful conditions. (C) 2003 Elsevier Science Ltd. All rights reserved.