Palynological characterisation of Amazonian rainforest communities, Northeast Bolivia

An ongoing controversy in Neotropical Palaeoecology is the extent to which Amazonian rainforest communities have responded to climate change over the last glacial-interglacial cycle. One way in which progress can be made in this field is to establish characteristic pollen signatures for different, biogeographically distinct rainforest communities, to compare these with fossil pollen assemblages numerically and thereby extract additional ecological information from the Quaternary sedimentary record. To this end, this thesis aims to (a) improve the identification of abundant rainforest pollen types to a finer taxonomic resolution; (b) provide pollen signatures for four Amazonian rainforest communities of the Noel Kempff Mercado National Park (NKMNP) situated within the Madeira-Tapaj6s ecoregion based on data obtained from a network of study plots and (c) compare these modern analogue signatures with core-top pollen assemblages recovered from the sedimentary record of lakes within the park.Descriptive and morphometric methods are used to identify and differentiate key pollen types of the Moraceae family (Brosimum, Helicostylis, Pseudo/media, Sorocea and Pourouma) that are well represented in Amazonian rainforest communities of NKMNP. Using multivariate and cluster analyses applied to modern-pollen and floral-biometric data obtained from study plots situated within rainforest communities of the park, it is demonstrated that terrafirme (weU-drained) evergreen, terra firme Liana, seasonally inundated, and riparian rainforests are readily characterised by their pollen rain. Analogue matching techniques are employed to numerically compare the resulting signatures with core-top pollen assemblages taken from the Quaternary sedimentary record of two lakes within the park, and of three others situated in the floristically distinct Llanos de Moxos ecoregion. Such comparisons demonstrate that riparian forest communities represent the closest modem analogue for poIJen assemblages obtained from surface sediment samples from lakes within NKMNP; however, elements of terra firme forests also constitute a significant proportion of these assemblages. There is a clear separation of pollen trap and surface sediment spectra obtained from NKMNP from those obtained from outside the park reflecting floristic differences between rainforests of the MadeiraTapaj6s ecoregion and gallery forests of the Llanos de Moxos ecoregion. These results not only provide the potential for much more detailed and reliable Neotropical palaeovegetation reconstructions but also enable the improved estimation of past carbon storage from Amazonian fossil pollen records