Characterisation of Sanguinhal Mire, Terceira Island (Azores): a protected quaking bog habitat

Abstract

The Azores archipelago in the North Atlantic is an important area for biodiversity because it is rich in rare species and habitats, and almost undisturbed. Sanguinhal mire was originally a lake that evolved through paludification into a peat habitat. It is located inside Nature 2000 (European Union for Protection of Nature and Biodiversity, Council Directive 92/43/EEC of 21 May 1992 on the conservation of natural habitats and of wild fauna and flora, Habitat Directive Annex I(b) habitat 7140) area of Santa Bárbara and Pico Alto Mountains on the island of Terceira, and it is a good example of a basin peatland type that was first discovered in 1998. This paper provides baseline information on its flora, vegetation communities, structure, surface hydrology and chemistry. Forty-one plant species including six Sphagnum species and ten endemic vascular plants have been recorded, and eight plant communities are distinguished. The maximum peat depth is 2.5 m. The mire receives flowing water from its margins, in addition to intercepted precipitation and fog. After precipitation, water drains through several placic rupture points. Both pH and water conductivity were measured, with some ecological tendencies observed. The conservation status of the mire is good, but it is subject to increasing pressure from cattle pasture and a walking trail that constrains natural surface water movement.