Résumé

ABSTRACT: Guide to the Geobotanical Excursion to the Natural Park of “Serra de Aire e Candeeiros”. The “Serras de Aire e Candeeiros” Natural Park, in the Centre of Portugal, are mostly formed by limestone formations of the Middle Jurassic. Among the plant species located in this Protected Area, there are seven endemic species included in Annex II and/or IV of CEE/92/43 Directive by their rarity: Arabis sadina, Coincya cintrana, Iberis procumbens subsp. microcarpa, Juncus valvatus, Narcissus calcicola, Saxifraga cintrana and Silene longicilia. Other noteworthy plant species occurring in these limestone formations, although not included in any of the CEE/92/43 Directive annexes, are numerous orchid species and also Anthyllis vulneraria subsp. lusitanica, Crambe hispanica, Cytinus ruber, Dianthus cintranus subsp. barbatus, Jonopsidium abulense, Inula montana, Koeleria vallesiana, Orobanche latisquama, Scabiosa turolensis, Serratula baetica subsp. lusitanica, Serratula estremadurensis, and Teucrium chamaedrys, most of them of rare occurrence in Portugal. The vegetation of these hills, in its ridge line, consists of a mosaic of more or less degraded communities of the holm forest Lonicero implexaeQuercetum rotundifoliae. In the valleys and foothills of Serra dos Candeeiros, reaching as far as Minde, the Portuguese oak forest Arisaro-Quercetum broteroi dominates. In the last years, we verify the expansion of the arborescent matorral with the consequent decrease of grasslands as a result of the sucessional dynamics. In this paper a brief review on biogeography and bioclimatology of the Portuguese Divisory Sector is presented. The vegetation of the places visited during the Geobotanical excursion” is also described, including new plant communities recognized in this Sector. Three new associations are proposed: Oenantho crocatae Quercetum pyrenaicae (Populenion albae, Populion albae, Populetalia albae, Salici purpureae-Populetea albae), Trifolio pratensis-Phalaridetum coerulescentis and Arabido lusitanicae-Hordeetum bulbosae (Gaudinio verticolae-Hordeion bulbosae, Holoschoenetalia, Molinio-Arrhenatheretea). Keywords: limestone, karst, vegetation, flora