Relationships between contemporary and subfossil macrophyte assemblages in Mediterranean ponds

Abstract

Mediterranean ponds have been historically far less studied than temperate lakes of northern Europe and, for this reason, the availability of historical data is limited for these endangered ecosystems. In the absence of such data, macrofossils from surface sediment may provide highly relevant information concerning modern and past assemblages. Herein we explore the correspondence between contemporary macrophyte assemblages and their sedimentary remains from surface sediment in 35 ponds located in the North Iberian Plateau. The results show that plant macrofossils reflect both the contemporary communities from which they are derived and the environmental forces controlling their assemblage composition (primarily total phosphorous and chlorophyll-a). Overall, macrofossils may represent a useful tool for reconstructing the historical evolution of macrophyte communities, as well as the driving environmental variables, in the poorly investigated Mediterranean ponds. However, the absence of some littoral and helophytic remains in the surface sediment samples may indicate that caution should be exercised to avoid potential biases when reconstructing past macrophyte communities. Hence, we suggest that addressing the effects of coring location and the complex patterns of production and distribution of subfossils in relation to their source vegetation may provide intriguing insights for future research in Mediterranean paleolimnology.