May 5, 2022
Gosling, W.D., Miller, C.S., Shanahan, T.M., Holden, P.B., Overpeck, J.T. & van Langevelde, F. (2022) A stronger role for long-term moisture change than for CO2 in determining tropical woody vegetation change. Science 376, 653-656. https://doi.org/10.1126/science.abg4618
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For more on the palaeoecological dataset underpinning this research check out the PhD thesis of Charlotte Miller by clicking here or here.
January 22, 2020
Detecting the presence, and impact, of peoples past impact in ecosystems and landscapes in the tropics is a challenging because the traces that they leave behind are few and disentangling them from ‘natural’ (non-human related) variability is a challenge. As an Associate Editor for Vegetation History & Archaeobotany (VHAA) I enjoy handling manuscripts that think about these issues and explore the role of humans in tropical landscapes. Two recent papers published in VHAA touched on this subject (one of which I “communicated” as an editor).
May 13, 2014
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)
Abstract:
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.
Supervisors: Dr. William D. Gosling , Dr. Angela Coe (both The Open University), and Steve Brooks (Natural History Museum).
Examined by: Prof. Henry Hoogheimstra (University of Amsterdam), and Prof. Bob Spicer (The Open University).
To borrow a copy from The Open University Library click here.
Ecology of the past 