At present there is uncertainty over the response of neotropical ecosystems to the climatic changes of the Quaternary. The majority of vegetation reconstructions from the region are derived from fossil pollen records extracted from lake sediments. However, the interpretation of these records is restricted by limited knowledge of the contemporary relationships between the vegetation and pollen rain of neotropical ecosystems, especially for more open vegetation such as savanna and dry forest. This research aims to improve the interpretation of these records by investigating the relationship between the vegetation and modern pollen rain of different savanna and seasonally dry tropical forest (SDTF) ecosystems in Bolivia using artificial pollen traps and surface lake sediments to analyse the modern pollen rain. Vegetation data is used to identify taxa that are floristically important within the different ecosystems and to allow modern pollen/vegetation ratios to be calculated. The modern pollen rain from the upland savanna is dominated by Moraceae/Urticaceae (35.1%), Poaceae (29.6%), Alchornea (6.1%) and Cecropia (4.1%), whilst the seasonally-inundated savanna sites are dominated by Moraceae/Urticaceae (30.7%), Poaceae (19.5%), Cyperaceae (14.0%) and Cecropia (7.9%). These two different savanna ecosystems are only slightly differentiated by their modern pollen rain. The main taxa in the modern pollen rain of the upland SDTF are Moraceae/Urticaceae (25.8%), Cecropia (10.5%), Acalypha (7.6%) and Combretaceae/Melastomataceae (6.7%). Seasonally-inundated SDTF is dominated by Cecropia pollen to the extent that it was removed from the pollen sum and the main non-Cecropia pollen types are Moraceae/Urticaceae (39.0%), unknown type df 61 (6.4%), Asteraceae (6.3%), Celtis (6.0%) and Physocalymma scaberrimum (4.9%). These two SDTF ecosystems are well differentiated by their modern pollen rain, implying that they may be defined in fossil pollen records. The modern pollen rain obtained from the surface lake samples is generally complementary to that obtained from the artificial pollen traps for a given ecosystem. All sites have a high Moraceae/Urticaceae pollen signal due to effective dispersal of this pollen type from areas of evergreen forest in close proximity to the study sites. The savanna sites show lower Poaceae percentages than have been previously reported in the literature by some authors and this raises the possibility than the extent of this ecosystem in the past may have been underestimated. Modern pollen/vegetation ratios show that many key vegetation types are absent/under-represented within the modern pollen rain.

More often than not, when people think of a neotropical forest, what comes to mind is a rain forest, rather than a dry forest. Just as typically, when they imagine a savanna, they visualize the African plains, rather than those dry woodlands and grasslands found in the Neotropics. These same preconceptions can be found among scientists, as these ne

More often than not, when people think of a neotropical forest, what comes to mind is a rain forest, rather than a dry forest. Just as typically, when they imagine a savanna, they visualize the African plains, rather than those dry woodlands and grasslands found in the Neotropics. These same preconceptions can be found among scientists, as these ne

This updated and expanded second edition of a much lauded work provides a current overview of the impacts of climate change on tropical forests. The authors also investigate past, present and future climatic influences on the ecosystems with the highest biodiversity on the planet. Tropical Rainforest Responses to Climatic Change, Second Edition, looks at how tropical rain forest ecology is altered by climate change, rather than simply seeing how plant communities were altered. Shifting the emphasis on to ecological processes, e.g. how diversity is structured by climate and the subsequent impact on tropical forest ecology, provides the reader with a more comprehensive coverage. A major theme of the book is the interaction between humans, climate and forest ecology. The authors, all foremost experts in their fields, explore the long term occupation of tropical systems, the influence of fire and the future climatic effects of deforestation, together with anthropogenic emissions. Incorporating modelling of past and future systems paves the way for a discussion of conservation from a climatic perspective, rather than the usual plea to stop logging. This second edition provides an updated text in this rapidly evolving field. The existing chapters are revised and updated and two entirely new chapters deal with Central America and the effect of fire on wet forest systems. In the first new chapter, the paleoclimate and ecological record from Central America (Lozano, Correa, Bush) is discussed, while the other deals with the impact of fire on tropical ecosystems. It is hoped that Jonathon Overpeck, who has been centrally involved in the 2007 and 2010 IPCC reports, will provide a Foreword to the book.