Ephemeral Wetland Vegetation in Mediterranean Heathland and Maquis Communities

Abstract

Ephemeral wetland vegetation in shallow depressions in gaps of woody vegetation is less prominent than vernal pool vegetation and thus often disregarded despite its protection by EU habitat directive. Depending on the variability of precipitation in the Mediterranean zone, ephemeral species vary considerably from year to year. My study examined whether the occurrence of ephemeral wetland vegetation in Mediterranean heathland and maquis (shrubland) communities is associated with certain scrub types. I also investigated whether the cover of dwarf rush communities can be quantified by dependence on topographic parameters on a landscape scale. The study area, chosen as a typical heath-maquis example, lies in Southern Spain. I analyzed the vegetation complexes using classification by floristic similarity and indirect and direct ordination techniques. Habitat suitability modelling was made using generalized linear models. The results show that ephemeral wetland vegetation was associated with maquis communities dominated by Pistacia lentiscus. Atlantic heathlands did not co-occur with ephemeral wetlands. Ephemeral wetland species were rare in scrub communities on clayey soils. The cover of ephemeral wetland vegetation in shallow depressions could be well predicted with topographic variables at a 10 m × 10 m resolution. The inclusion of soil moisture, a variable only available for the sampling sites, enhanced model predictions remarkably. Modelling of the cover of ephemeral wetlands is crucial for the consideration of these communities in conservation planning.