Influence of the Vegetation Cover in the Soil Biomarker Assemblage Under Rhododendron and Oak Stands

摘要

Rhododendron ponticum L. ssp. baeticum (Boissier & Reuter) Handel-Mazzetti is a relict of the Tertiary forest that persists in moist habitats, in SW Spain and Southern and Central Portugal. Is an aggressive invader of temperate deciduous forests, in Western and Central Europe [1]. The ecological study of Rhododendron in its native habitat is relevant for the conservation of plant communities subjected to invasion worldwide. Factors determining present area limitation and ecological constraints restricting the expansion have been reported [2]. However the influence of soil organic matter molecular composition is still poorly understood. Among its different fractions, lipids play a key role in the relationship between plants and their environments [3]. This is relevant since a frequent observation in temperate forests invaded by Rhododendron is the accumulation of plant litter on the soil surface. The high content of secondary compounds in leaves deterring herbivores, can contribute to invading success [4], but also allelopathic effects on soil biota and accompanying vegetation may also occur. In this work a comparative GC/MS study of biomarker assemblage is performed in soil under Rhododendron stands and adjacent sites with deciduous oak, Quercus canariensis Willd., in Southern Spain (Sierra de Luna, Cadiz).