NEW LOCATIONS AND HABITAT STUDY OF THE RARE IBERIAN ENDEMISM

Abstract

Serapias perez-chiscanoi Acedo is an Iberian endemism (Orchidaceae) initially found along the Guadiana river basin (Extremadura of Spain), in wet (not flooded) grasslands, on siliceous sands, from 100 to 400m. The species’ presence in Sado Basin (Portugal) was first discovered by Pereira et al. (2008) in Baixo Alentejo (Alvito, Vila Nova da Baronia). This population (200 individuals) was monitored from 2002 to 2007, in order to study the habitat characteristics and ecological succession. Very recently, two new locations were found in Central Portugal: one close to Abrantes (Alferrarede), and another in Serra de Sicó (Pombal, Ereiras), locating the taxon in the basins of the rivers Tagus and Mondego, respectively. Although it is considered rare, being protected under Spanish laws, this orchid occurs in vulnerable habitats that require conservation. Still little is known about its biology and ecology, and it does not benefit from any legal protection in Portugal. This work comprises its habitats in Portugal, focusing in flora and vegetation analysis (classic sigmatist method of Braun-Blanquet, phytosociological relevés and tables), geology, biogeography, bioclimatology and top soil characteristics. The population near Alferrarede (occurring in a degraded clearing of Eucalyptus sp. forest), is placed in the cork oak climatophilous series gaditan-algarvian and lusitan-extremadurean Asparago aphylli-Querceto suberis sigmetum, and its sub-serial stages Erico scopariae-Quercetum lusitanicae, Asparago aphylli-Myrtetum communis, Thymo villosi-Ulicetum airensis and Trifolio cherleri-Plantaginetum bellardii. The population found in 2010 in Ereiras, in calcareous substrates, is included in the Nature 2000 Network (Sítio Sicó/Alvaiázere - PTCON0045). The dominant climatophilous series is Arisaro-Quercetum broteroi sigmetum, endemic for the Dividing Portuguese and Ribatagan-Sadensean sectors, with the sub-serial stages Lavandulo luisieri-Ulicetum jussiaei, Phlomido lychnitidis-Brachypodietm phoenicoidis (correspondent to the priority habitat “6210: Semi-natural dry grasslands and scrubland facies on calcareous substrates (Festuco Brometalia)(*important orchid habitats)”) and Trifolio cherleri-Plantaginetum bellardii. The studied habitats share a strong Mediterranean character, having a preference for moist soils covered by perennial and annual grasslands (in humid depressions of the soil), at the humid fringes of Ulex sp. heaths, in the understorey of oak formations.