Modern pollen rain in Canary Island ecosystems and its implications for the interpretation of fossil records

Vegetation history in the Canary Islands, one of the most biodiverse regions within Europe, has recently and for the first time, been the subject of palaeoecological studies. The interpretation of fossil records may be limited by several uncertainties regarding how well the different vegetation types are represented in the pollen rain. In this study we address this key knowledge gap within Canarian vegetation science, taking the island of Tenerife as a model. Based on quantitative and qualitative data we analysed pollen-vegetation relationships to test whether different vegetation types can be discriminated by means of their pollen rain composition, to identify under- and over-represented taxa, and to test the match between modern pollen rain and fossil pollen assemblages. We found clear differences in pollen composition and abundance among major Canarian vegetation types. We also identified good indicator taxa of the local occurrence of their source plants by their high fidelity and low dispersibility index scores. Extra-regional types (taxa without potential source plants in the Canary Islands) were not detected in our traps. However, several important floristic elements are either over-represented (Pinus, Morella and Ericaceae trees, Chenopodiaceae, Poaceae, Rumex and Urticaceae herbs and shrubs) or under-represented (Lauraceae trees, Fabaceae and Euphorbia shrubs). Results indicate that pollen composition is a good reflection of vegetation in Canarian ecosystems and can be used effectively to reconstruct past environments.