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Acer monspessulanum(maple) is an endemic endangered tree with a wide but fragmented distribution in the Mediterranean mountains. The persistence of its small populations depends often on few adults, which makes it is highly vulnerable to limiting recruitment factors. In this paper, we examined the regeneration status of this maple in three populations through its geographical distribution in the mountain range of the Tunisian dorsal (Jbel Srerej national park and sacred site). Morphological parameters, genetic variability, and diversity were analyzed as species viability indicators. The ecological site of maple was studied based on the soil texture and structure under the population, additionally to the role of shrubs as nurse plants in maple regeneration dynamic. Here, the maple population in Tunisia was investigated for the first time. The results show thatAcer monspessulanumpopulation has a variation terms of height, stem diameter and crown diameter, it also shows that there is a good natural regeneration. Analysis of the soil’s physicochemical parameters showed that the species grows on sandy loam and clay loam soil, shallow and slightly alkaline pH. This study contributes to better characterization of the Tunisian maple population and its ecological niche from the standpoint of soil and vegetation. [ABSTRACT FROM PUBLISHER]

Whether biological diversity within communities is limited by local interactions or regional species pools remains an important question in ecology. In this paper, we investigate how an experimentally applied tree-harvesting disturbance gradient influenced local-regional richness relationships. Plant species richness was measured at three spatial scales (2 ha = regional; 576 m² and 1 m² = local) on three occasions (one year pre-disturbance, one year post-disturbance, and 10 years post-disturbance) across five disturbance treatments (uncut control through clearcut) replicated throughout the southern Appalachian Mountains, USA. We investigated whether species richness in 576-m² plots and 1-m² subplots depended on species richness in 2-ha experimental units and whether this relationship changed through time before and after canopy disturbance. We found that, before disturbance, the relationship between local and regional richness was weak or nonexistent. One year after disturbance local richness was a positive function of regional richness, because local sites were colonized from the regional species pool. Ten years after disturbance, the positive relationship persisted, but the slope had decreased by half. These results suggest that disturbance can set the stage for strong influences of regional species pools on local community assembly in temperate forests. However, as time since disturbance increases, local controls on community assembly decouple the relationships between regional and local diversity. [ABSTRACT FROM AUTHOR]