Ecological and human land-use indicator value of fungal spore morphotypes and assemblages
Résumé
The value of non-pollen palynomorphs (NPPs) to complement reconstructions of past communities and environments has led to the identification of an increasing number of microfossil morphotypes. Unfortunately, limited knowledge about their specific ecological indicator values still restricts the interpretation of NPP accumulation rates or assemblage variations. Here, a comparison with classical palaeoecological proxies along a sedimentary sequence has been tested to improve the ecological indicator values of NPP morphotypes. Pollen, geochemical and NPP analyses performed on the same samples all along the Holocene sedimentary sequence of Lac de Moras (France) were compared using principal component analysis to identify statistical relationships and to establish correlations between all these parameters. Ecological indicator values were obtained for some morphotypes such as UG-1097 which is related to specific taxa (Corylus sp.), or Diporotheca rhizophila defined as an indicator of the local presence of alder swamp habitat. However, most of the NPP morphotypes can be combined in two opposite NPP assemblages reflecting the change from natural to managed ecosystems at the drainage basin scale and over the Holocene. It more specifically illustrates a change in the source of organic matter transferred to the lake system provided from the plant debris of woodland cover (litter) to organic matter from animal excreta (dung and manure).