Coastal Soils and Their Associated Habitats in Galicia

Resumo

Galicia is one of the Spanish autonomous communities with the longest coastline, one of the most complex in the Iberian Peninsula. Dune, marsh, and cliff environments are interspersed along coastal areas, on which soils with highly contrasting features and properties develop. In dune environments, soils show poor edaphic development, with the addition of organic matter and substrate decalcification as the main processes. The most representative soil types are Calcaric Arenosols, corresponding to white and grey dune areas, and Calcaric Gleyic Arenosols, associated with inter-dune depressions, where small seasonal lagoons form. The main characteristics and diagnostic features in saltmarsh soils are gleyic properties, sulfidic materials, and concentration of salts derived from marine influence. The most representative soils are Reductigley Tidalic Gleysol (Hyposulfidic), characteristic of salt marsh plains and corresponding to habitat Nat2000 1330, Atlantic salt meadows; Histic Tidalic Gleysol (Hipersulfidic, Toxic), a soil type characteristic of back saltmarshes, where the Scirpus maritimus community is located, are organic soils with a strongly reduced horizon already at their surface (Eh < 100 mV), high pyrite and H2S contents, but low salinity; Reductigley Tidalic Gleysol (Hypersulficic), associated with the presence of Spartina maritima, are strongly reduced soils with high pyrite concentrations, and Reductigley Subaquatic Gleysol (Hyposulficidc), which corresponds to submarine Zostera nolti and Zostera marina meadows, are anoxic at their surface and show high contents of sulfidic materials. Cliff soils are characterized by being shallow, slightly acidic, with high organic matter content, low electrical conductivity, and the cation exchange complex saturated by basic cations. According to these variables, soils are classified as Lithic Leptosol (Arenic), Mollic Leptosol (Arenic) and Mollic Umbrisol (Arenic, Colluvic). The main habitat associated with these soils is Nat2000 1230 Vegetated sea cliffs of the Atlantic and Baltic Coasts, which in Galicia is still poorly characterized.