Patterns and ecological consequences of abiotic heterogeneity 8 in managed cork oak forests of Southern Spain

9 10 Received: 5 October 2006 / Accepted: 11 January 2007 11 ! The Ecological Society of Japan 2007 2345678 19 20 Abstract Spatial heterogeneity of abiotic factors influ21 ences the structure and function of forests and must be 22 taken into account for their conservation and sustain23 able management. In this study, we evaluate the heter24 ogeneity of abiotic environmental variables in managed 25 cork oak (Quercus suber L.) forests in southern Spain at 26 patch, site and regional scales. The extent of spatial 27 heterogeneity depended on the environmental variable 28 examined and the scale considered. For example, soil 29 Mn and P and light availability in the understorey were 30 very heterogeneous at the regional scale, while soil N 31 had low regional heterogeneity, but high spatial 32 variability, at patch scale, attributed to open overstorey 33 and grazing disturbance. There was a general trend of 34 increasing heterogeneity with spatial scale. We also 35 study the effects of a silvicultural practice—shrub 36 clearing on the forest environment and its consequence 37 for spatial heterogeneity. Shrub clearing increased 38 understorey light and decreased its spatial heterogeneity 39 with idiosyncratic effects on soil properties and their 40 spatial heterogeneity at each site. Finally, we compare 41 the heterogeneity (estimated by the coefficient of varia42 tion) obtained in these cork oak forests with a database 43 compiled from published studies on other forest envi44 ronments. The comparison revealed a remarkable extent 45 of abiotic heterogeneity in the cork oak forests studied, 46 suggesting that a sustainable management of these for47 ests should combine intrinsic and human induced abiotic 48 heterogeneity to preserve crucial ecological processes 49 and to maintain high levels of biodiversity.