Non-pollen palynomorphs from surface sediments along an altitudinal transect of the Venezuelan Andes

Palynological studies including records of non-pollen palynomorphs (NPP) are uncommon in the Neotropics, in spite of their demonstrated usefulness in other regions. Modern analog studies to improve palaeoecological interpretations of NPP are even more scarce. Here, we report the NPP assemblages recorded in modern surface samples from an altitudinal transect of the Venezuelan Andes, ranging from about 2300 and 4600 m. We compared the assemblages with the results of previous pollen analyses of the same samples. The variables considered to explain NPP patterns along the transect are altitude and the local habitat of the sampling site (“sample type”). A total of 65 NPP taxa - classified into algal and zoological remains, and fungal spores - have been found. Unidentified taxa (23) have been named with a code, depicted and described for further reference. Fungal spores are well represented along the whole transect, whereas algal and zoological remains are absent or very scarce in the lower and the uppermost ranges. The altitudinal zonation of fungal spores matches with that of pollen and the corresponding vegetation belts, suggesting a close relationship. The known environmental requirements of some of the fungi identified allowed inferences on particular ecological features, in agreement with previous palynological interpretations. Both elevation and sample type are needed to explain the observed differences in the assemblages of the three groups, the elevation being more decissive for fungal spores and the local habitat of the sampling site for algal and zoological remains. The sample type effect is minimised when the NPP studied are considered altogether, thus increasing their usefulness as palaeoecological proxies. This study reinforces the utility of modern analog surveys of NPP with palaeoecological purposes and encourages further research, particularly in poorly known areas, as for example tropical regions.