Human-Impact Gradients through Anthropogenic Pollen Indicators in a Mediterranean Mosaic Landscape (Balearic Islands)

Abstract

This paper proposes new anthropogenic pollen indicators for the Balearic Islands and attempts to assess gradients of human impact on vegetation in Mediterranean islands. A combination of modern pollen analogue studies, complemented by phytosociological descriptions and ordination techniques using quantitative and presence/absence data was used. Redundancy analysis allowed us to evaluate the relationships between pollen types and significant environmental variables and propose regional (e.g., Centaurea, Rubus, Plantago lanceolata-t) and local/microregional anthropogenic pollen indicators (e.g., Cerealia, Poygonum aviculare, Matricaria-t). Additionally, an anthropogenic index score (AIS) for each sampled location was calculated to correlate each pollen type to a specific degree of human impact: (a) low (e.g., Cerastium-t, Erica arborea-t, Cistus albidus), (b) moderate (e.g, Sinapis-t, Sanguisorba minor-t, Plantago bellardii-t), (c) high (e.g., Papaveraceae undiff., Dipsacaceae, Secale-t). This paper contributes to a further understanding of land-use dynamics and to defining the degree of impact, which is especially necessary to assess colonization and anthropization rhythms in Mediterranean island environments.