Spatial pattern of Quercus ilex and Quercus pubescens recruitment in Pinus halepensis dominated woodlands

Abstract

Abstract. European Mediterranean landscapes have undergone changes in structure in recent years as a result of widespread agricultural land abandonment and cessation of silvicultural regimes. Studies concerning the regeneration dynamics of dominant forest species have become critical to the prediction of future landscape trends in these changing forest stands. Quercus ilex (holm oak) and Q. pubescens (downy oak) are considered to be the terminal point of secondary succession in extensive areas of the Mediterranean region. Recent studies, however, have suggested the existence of recruitment bottlenecks in oak genet populations as a result of current management regimes. In this study, we present evidence of the successful establishment of Q. ilex and Q. pubescens in Pinus halepensis (Aleppo pine) woodlands. We investigate the distribution patterns and spatial relationships among oak recruits and resident pines. Established P. halepensis is randomly distributed throughout the study area. Oak seedlings are positively associated with pine trees, suggesting that P. halepensis individuals provide safe sites for oak genet recruitment. We show that spatial patterns of recruitment are in agreement with the general model of spatial segregation described for other Mediterranean plant communities, with seeder species colonizing large openings after disturbance, followed by a more aggregated recruitment of resprouter species.

Patterns of shrub diversity and tree regeneration across topographic and stand-structural gradients in a Mediterranean forest

“…These findings and differences in seedling abundance (Table 1) suggest that currently dominant Pinus nigra forests could be replaced by more mixed pine-oak stands at lower altitude sites, whereas it would probably persist as the sole or dominant species at higher altitudes. A replacement of pine by oak would agree both with previous studies conducted in Mediterranean pine forests (Lookingbill & Zavala, 2000) and with the observed higher shade tolerance of Quercus compared with pine seedlings (Figure 3). However, successional change is likely to depend on the silvicultural treatments applied and on acorn dispersal.…”

Temperate-like stand dynamics in relict Mediterranean-fir (Abies pinsapo, Boiss.) forests from southern Spain

“…Some of the processes (e.g., competition for light and selfthinning), which underlie gap dynamics in temperate forest ecosystems, may differ under a Mediterranean climate, since soil moisture can be a decisive factor in addition to light availability. In fact, many studies have reported that vertical growth of Mediterranean tree species is not controlled by apical dominance, as is common in temperate forests (Vilà and Sardans, 1999), because shade tolerance is not the main regulator of forest succession under Mediterranean conditions (Benayas, 1998;Lookingbill and Zavala, 2000). All this suggests that increasing seasonality and summer drought, as predicted by climate-change models for temperate-boreal regions of Europe, will have profound consequences on the stand structure and gap dynamics of forest ecosystems, including Abies spp.…”

Nursery cultivation regimes, plant functional attributes, and field performance relationships in the Mediterranean oak Quercus ilex L.

“…As holm oak is a late succession species and seedling recruitment benefits from canopy shade of mature tress and early successional species (Lookingbill and Zavala, 2000), it is frequently cultivated under a half shade. This practice is considered to produce higher quality seedlings because it presumably reduces foliar damage caused by the heat load and high irradiation that occurs during the summer.…”