Environmental patterns and plant communities of the ephemeral wetland vegetation in two areas of the Southwestern Iberian Peninsula
In two regions in the Southwestern Iberian Peninsula, the Serra de Monchique (Portugal) and the Campo de Gibraltar (Spain), Isoeto-Nanojuncetea communities constitute the ephemeral wetland vegetation. Macroscale patterns varying with altitude and slope aspect are studied, as well as microscale patterns depending on soil physical properties.In the Serra de Monchique the ephemeral wetland vegetation occurs on gravel cushions above syenite rock. In the Campo de Gibraltar, these communities, interspersed in gaps of Erica scoparia-E. ciliaris-heathland, are more frequently in contact with perennial meadows or fens. The following communities are represented: Isoetetum durieui, Laurentio michelii-Juncetum tingitani, Junco capitati-Isoetetum histricis, and Loto subbiflori-Chaetopogonetum fasciculati. Altitudinal zonation of the communities is clearer in the Campo de Gibraltar than in the Serra de Monchique. In both regions the Junco-Isoetetum shows the largest altitudinal amplitude. Generally the site conditions are characterised by a high amount of available soil moisture and in the Serra de Monchique by a high air capacity. The Portuguese samples are clearly distinguishable from the Spanish samples by soil physical properties. Nutrient poor soils prevail in both regions. The habitat of the Loto-Chaetopogonetum is characterised by a high proportion of micropores. The microscale pattern of the dwarf rush communities on gravel cushions is marked by the soil depth, by the gravel import rate, and by seeping water at the lower margin of gravel cushions.In syenite gravel in the Serra de Monchique, the Helianthemo guttati-Plantaginetum bellardii (Helianthemetea) co-occurs with ephemeral wetland vegetation. Five subassociations, four of them new, can be differentiated: Helianthemo guttati-Plantaginetum bellardii typicum, Helianthemo-Plantaginetum arenarietosum conimbricensis, Helianthemo-Plantaginetum sedetosum andegavensis, Helianthemo-Plantaginetum silenetosum scabriflorae, and Helianthemo-Plantaginetum plantaginetosum coronopi.