Role of bryophytes in the vegetation of Mediterranean temporary ponds close to the temperate bioclimatic border

Preliminary data on the bryoflora of the temporary pools and waterlogged soils in Piana di Ferretto (Umbria, inland Central Italy), a biotope of great conservation interest and a Natura 2000 site (IT5210020), are here discussed and interpreted in the light of the vascular plant communities which house them. The area belongs to the Mesomediterranean belt of the Mediterranean Bioclimate, although transitional traits to the Temperate Bioclimate affect its floristic and ecologic features. The Mediterranean temporary pond systems can only seldom develop in such inland territories, depending on a peculiar combination of water regime, mesoclimate and soil characteristics. Bryological data from the area date back to the 80s (Cortini Pedrotti, 1985; Aleffi, 1992), while the vascular component has been firstly studied in the 80s and more recently reorganized in a phytosociological framework including new and complete descriptions of amphibian plant communities (Gigante et al., 2013). Eight vegetation types were identified: Junco-Solenopsietum laurentiae, Hypochoerido-Cicendietum filiformis, Callitricho-Ranunculetum ophioglossifolii, Callitricho-Juncetum bulbosi, Serapio-Isoëtetum histricis lotetosum angustissimi, Solenopsio-Juncetum pygmaei isolepidetosum cernuae, Alismo-Gratioletum officinalis juncetosum conglomerati, Callitricho-Ranunculetum ophioglossifolii glycerietosum fluitantis. Twenty-eight taxa of mosses and liverworts (23 Bryophyta, 5 Marchantiophyta) were found in the area, identified and named following Cortini Pedrotti (2006) and Aleffi et al. (2008). Eight species are new records for Umbria: Campylopus introflexus, C. pilifer, Dicranella cerviculata, Ephemerum recurvifolium, Fossombronia wondraczekii, Plagiomnium ellipticum, Pohlia nutans, Riccia canaliculata. According to Aleffi & Schumacker (1995) and the European Committee for Conservation of Bryophytes (ECCB), R. canaliculata is considered vanished (Ev) in the region, F. wondraczekii and R. beyrichiana are considered rare (R), showing the high relevance of these systems, also emphasized by the presence of two Habitats from 92/43/EEC Directive's Annex I (3110, 3170*). Furthermore, the study area shows remarkable peculiarities, in that its transitional climatic condition generates a shift between bryophyte and vascular species phenology. The bryophytic species show a late-winter development and disappear almost completely before the vascular communities reach their maximum level of development (start of May). This prevents from the possibility to include bryophytes in the vegetation relevés. With the present study, based on diachronic samplings and the use of gps technology, it was possible to relate the bryophytic species to each vascular plant community.