Geological heritage of the international Douro Natural Park (NE Portugal): geoconservation strategies

Abstract

The PNDI is an example of a national protected area with a notable geodiversity and peculiar landscapes associated with the fluvial canyons of the international Douro and Águeda Rivers (NE Portugal-Spain border; Fig. 2, Plate D). The spectacular steep cliffs, regionally named Arribas do Douro, are the major landscape feature of the region and the ‘ex-libris’ of the PNDI (Fig. 3, Plate D). They were developed during the incision of the Douro River and its tributaries on the Iberian Meseta, crosscutting granitic and metasedimentary terranes, under the control of the fracture network. This geological setting provides one of the most important nesting habitat in Europe for vultures, eagles and black storks. The floristic heritage found on the rock slopes and ancient floodplains is also relevant. Evidence of the close relationship with the geological characteristics is also given by the millenary human occupation of the abrupt slopes, profiting from the microclimatic conditions for the production of wine, olive and almond, as well as by the traditional uses of geological materials by man. In conclusion, the PNDI has a relevant geological heritage (Ferreira et al ., 2003), which provides the support for its biodiversity. Therefore, the nature conservation policies must take this strong linkage into account. Since 2000 Portuguese geologists from the University of Minho and from the Geological Survey are working together in protected areas from Northern Portugal, namely in the PNDI in the scope of a multidisciplinary research project (PNAT project), sponsored by FCT (Portuguese Science and Technology Foundation) and ICN (Portuguese Nature Conservation Institute). This project aims to: (i) improve the geological knowledge in the PNDI; (ii) proceed with the inventory and characterisation of geosites; (iii) create scientific instruments to support a sustainable management of resources and territory; (iv) contribute to the increase of public awareness of Natural Heritage.