The Llanos de Moxos in Bolivia is an area the size of England that has one of the highest densities of archaeological sites in the Amazon basin. I travelled there for the first time earlier this month for the fourth International Meeting of Amazonian Archaeology. As the airplane crossed from the Andes into the Amazon plains, I could tell this was a very different ‘Amazonia’ compared with the forests that I know from Peru, Ecuador, and western Brazil. The Llanos de Moxos is a seasonally flooded savanna and it was so…open! I immediately realized that the perception of ‘Amazonia’ varies widely among individuals, and I think that is one of the reasons why those of us who study the human history of Amazonia tend to disagree so frequently.
Gosling, W.D., Julier, A.C.M., Adu-Bredu, S., Djagbletey, G.D., Fraser, W.T., Jardine, P.E., Lomax, B.H., Malhi, Y., Manu, E.A., Mayle, F.E. & Moore, S. (2017) Pollen-vegetation richness and diversity relationships in the tropics. Vegetation History and Archaeobotany. DOI: 10.1007/s00334-017-0642-y
Open access online:
Matthews-Bird, F., Gosling, W.D., Coe, A.L., Bush, M., Mayle, F.E., Axford, Y. & Brooks, S.J. (2015) Environmental controls on the distribution and diversity of lentic Chironomidae (Insecta: Diptera) across an altitudinal gradient in tropical South America. Ecology and Evolution. DOI: 10.1002/ece3.1833
Open access online:
Flantua, S.G.A., Hooghiemstra, H., Grimm, E.C., Behling, H., Bush, M.B., González-Arango, C., Gosling, W.D., Ledru, M., Lozano-García, S., Maldonado, A., Prieto, A.R., Rull, V. & Van Boxel, J.H. Updated site compilation of the Latin American Pollen Database. Review of Palaeobotany and Palynology 223, 104-115. DOI: 10.1016/j.revpalbo.2015.09.008
Williams, J.J. (2011) Human and climate impacts on tropical Andean ecosystems. PhD Thesis, Department of Earth & Environmental Sciences, The Open University.
JJW Bolivia (2007)
Population growth and predicted global climate change are applying new, and increasing, pressure to mountain environments, but the consequences of these changes upon the biodiverse and vulnerable Tropical Andean ecosystems are poorly understood. This thesis explores past human-climate-ecosystem interactions using multi-proxy palaeolimnological investigations (fossil pollen, spore, charcoal and Chironomidae (midges); elemental abundance, colour spectra and magnetic susceptibility) of two sites in the eastern Bolivian Andes (Lake Challacaba and Laguna Khomer Kocha Upper) over the last c. 18,000 years. During the deglaciation and Holocene ecosystems were exposed to varying climatic stress levels, and pressures imposed by the development of human cultures.
Examination of preserved ecological assemblages, including the first assessment of subfossil central Andean Chironomidae, reveals ecosystem sensitivity to changes in temperature, moisture, fire regime, lake level and salinity. Charcoal analysis from Laguna Khomer Kotcha Upper reveals changes in burning at c. 14,500, 10,100 and 6,400 cal yr BP. Concomitant palynological shifts shows this climatically controlled fire regime was a transformative agent of Andean vegetation, particularly for the threatened, high elevation, Polylepis woodlands. Pollen and geochemical data from Lake Challacaba indicate two periods of aridity (c. 4000−3370 and 2190−1020 cal yr BP), these broadly correlated to El Niño/Southern Oscillation variations. Increased Sporormiella abundance after c. 1,340 cal yr BP indicate changes in trade routes and agricultural practices; demonstrating human adaption to environmental change and interconnectivity to Tiwanaku and Inca civilizations.
The long-term response of the terrestrial and aquatic ecosystems, reconstructed from these lakes, has provided insights into how Tropical Andean ecosystems may respond to future changes in temperature, precipitation and human interference. The palaeoenvironmental data has implications for conservation management; it indicates that spatial and temporal variations in site sensitivity, exposure and resilience should be assessed, and that planting strategies should mimic the present day natural patchy distribution of Polylepis woodlands.
Gosling, W.D. (2004) Characterisation of Amazonian forest and savannah ecosystems by their modern pollen spectra. PhD Thesis, Department of Geography, University of Leicester.
WDG Bolivia (2002)
Controversy surrounds the Quaternary palaeoenvironmental history of Amazonia. It is unclear whether moist evergreen forest, savannah or seasonally dry forest dominated the Amazon basin at the last glacial maximum (c. 21,000 years B.P.). In part the uncertainty surrounding the palaeoenvironmental history of Amazonia stems from a poor understanding of the ecological significance of the fossil pollen records from the region. In order to improve interpretations of the fossil pollen record it is essential to better understand the nature of the pollen rain produced by modern ecosystems.
In this thesis, three Neotropical ecosystems equivalent to those alluded to above were characterised by their modern pollen rain. This was achieved by examining samples collected in artificial pollen traps located within permanent (50 x 200 m) vegetation plots in the Noel Kempff Mercado National Park area, Bolivia. In each plot 10 traps were sampled for one field season (September 1998 to September 1999, or September 2000 to September 2001) and 5 traps were sampled from two additional field seasons (between 1998 and 2001). Pollen counts of at least 100 grains were made for each trap. In total 318 pollen taxa were distinguished, of which 116 were identified. The characteristic pollen from each of the three ecosystems were determined through a series of steps: spatial and temporal variations were explored using Spearman’s Rank correlations, the distinctive taxa of each ecosystem were identified using Principal Components Analyses (PCA), and the representativity of the pollen for each ecosystem was examined by comparing pollen and vegetation abundances. These analyses revealed a small number of taxa that can be used to characterize these ecosystems. Further PCA showed that it is possible to differentiate between the ecosystems by assessing the relative proportions of Didymopanax, Alchornea, Anadenanthera, Melastomataceae/Combretaceae, Moraceae/Urticaceae, Myrtaceae, Palmae, Pteropsidia (trilete), Poaceae and Solanum. These findings mean that it is now possible to detect these ecosystems in the fossil pollen record and consequently further information regarding the nature of the vegetation change in the Amazon basin can be gained.
Trecking with sediment corer in the high Andes of Peru
When it comes to collecting sediments from lakes its all about having the right tools for the job. Working in remote areas of the tropics we tend to favour the Colinvaux-Vohnout corer; supplied by Vince Vohnout at Geo-core). The advantages of this system are:
its light-weight nature (can be backpacked or donkeyed into field sites), and
the cam system (which allows hammering to penetrate tough sediments).
Eric Martinez carrying an Avon Redstart back out from Laguna Khomer Kotcha (Williams et al., 2011a)
With the right platform (two banana boats and an A-frame) we have manged to retrive c. 20 m of sediment from 20 m of water (c. 40 m of drill rod extended); Lake Pacucha, Peru (Hillyer et al., 2009). More typically we use two Avon Redstart inflatables and a platform following the design of Colinvaux et al. (1999).
Rachel Gill and Encarni Montoya with sediment cores from Jamaica.
Quick and belated update on activity in March! Not sure where the time is going at the moment…
Early in the month we were delighted to welcome Prof. Jonathan Holmes and Rachel Gill from UCL who came to use our core splitter to open new sediment cores from Wally Wash Pond in Jamaica! A visit from Steve Brooks (Natural History Museum) early in the month to discuss midgy progress with Frazer was great. We are getting ever closer to developing a training data set… Also popping by was ex-PhD student and now Aberystwyth lecturer Joe Williams who we will hopefully be developing some new collaborations with over the summer and fingers crossed mounting an expedition back to Bolivia!