Edaphic behaviour of several species of Cistus in the Green Corridor of Guadiamar (Spain)

Abstract

Species of the genus Cistus are woody shrubs that are noteworthy for their use in forest restoration, and have often been used as characteristic species of the higher syntaxonomical units. In this paper we address their limits of tolerance and optimum development in terms of edaphic factors. The area of study is the "Green Corridor" of Guadiamar, a narrow strip of land that connects two large protected sites: the "Doñana Natural Park and National Park" and the "Aracena y Picos de Aroche" and "Sierra Norte de Sevilla" Natural Parks in Andalusia (Spain). We worked with six species (C. albidus, C. ladanifer, C. monspeliensis, C. populifolius, C. crispus and C. salviifolius) detected at 14 sites. In each of these sites, a soil sample and a phytosociological inventory were taken. The soil variables analyzed were exchangeable calcium, exchangeable magnesium, exchangeable sodium, exchangeable potassium, total carbonate, moisture content at saturation and pH. Among sampled species, C. albidus is the most tolerant to presence of calcium and carbonate, with a soil pH preferably close to neutral or moderately basic. Although not strictly a calcareous species, its ability to compete is nevertheless favoured in these environments. C. crispus appears in the soils with the lowest exchangeable bases, total carbonates, pH and moisture content at saturation. C. ladanifer is noted in soils with a low level of total carbonates. C. populifolius is associated with the highest moisture content at saturation. C. monspeliensis is the species that has the largest tolerance range, especially for pH values, and is the most xerophytic. C. salviifolius presents an intermediate behaviour respect to most of the variables, with a preference for moderately acid environments, although no strictly