Disentangling environmental change in the Amazon: vegetation responses to Holocene drivers in the National Park of Yasuni (Ecuador).


  • Supervisors: Encarni Montoya, University of Liverpool
    Fabienne Marret-Davies, University of Liverpool
    Rachel Smedley, University of Liverpool
    George Wolff, University of Liverpool
  • External Supervisors:

  • Contact:

    Encarni Montoya, University of Liverpool, emontoya@liverpool.ac.uk

  • CASE Partner:

Application deadline: 10 January 2020

Introduction:

Current environmental change is a global phenomenon that will have a devastating influence on the planet and the way we perceive it nowadays1. As an attempt of anticipating, the IPCC last report highlights the importance of studying the dynamics occurred in the past that are preserved in fossil sedimentary records as analogues to infer potential future directions that the Earth system may take1. Within the study of climate change in the long-term (>50 years), the analysis of the biota responses to those changes is equally needed. Palynological studies over the last 100 years have yield paramount information about long and short-term vegetation dynamics, but it remains geographically patchy. Research efforts in the tropics are under-represented compared to temperate locations such as Europe or North America2,3. Within tropical South America, lowlands hold some of the most biodiverse ecosystems4, so long-term vegetation dynamics' studies are needed to understand the functioning and conservation of these globally important areas. Moreover, recent advances in the increased number of both the techniques applied and locations studied in the region have highlighted a heterogeneous human occupancy pattern prior the European invasion. This lately observed occupancy may have played in some areas a key role in shaping the current landscapes and diversity5,6, which might be important when analysing the resilience of a given ecosystem in facing perturbations. In this sense, studies of past human occurrence, their landscape management and their interplay with other environmental drivers are crucial to understand past, current and future vegetation dynamics.

Project Summary:

The present project aims to study the long term dynamics of Amazonian lowlands’ forests of the Yasuni National Park (Ecuador). Sediment cores spanning since mid-Holocene collected along an ecological transect will be analysed for different geochemical and biological proxies including pollen (vegetation), non-pollen palynomorphs –NPP-, charcoal particles (fires), XRF (erosion), OSL (transportation) and biomarkers (precipitation). The sedimentary archives are located within a small spatial scale (10 km), at different distances from current major forcing factors such as human settlements or river channels. The project will investigate multiple aspects of the fossil record to reconstruct vegetation change and the causes driving these changes. Main objectives are:

1. To characterize the nature and composition of vegetation on the lowland forests in north-western Amazonian during the Holocene unravelling the onset dates and environmental conditions of the current landscape establishment.

2. To establish fire history, climate conditions and depositional environment at the study sites by examining fossil charcoal, NPP, biomarkers, XRF and OSL.

3. To assess the amount of vegetation change within eastern Andean tropical forests as a result of Holocene (i) climate change, (ii) river migration, or (iii) human influence.

Independent radiometric (14C) ages for the sites have already been obtained by supervisor Montoya and the samples required for vegetation reconstruction were obtained during field work in 2016. During the project the student will have the opportunity to visit the study sites and complete additional sampling. Field work will be conducted in association with partner Montúfar and the Pontificia Universidad Católica del Ecuador.

References:

1. IPCC, 2013. In: Stocker, T.F., Qin, D., Plattner, G.-K., Tignor, M., Allen, S.K., Boschung, J., et al. (Eds.), Climate Change 2013: the Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, p. 1535.

2. Grimm, E.C., Keltner, J., Cheddadi, R., Hicks, S., Lézine, A.-M., Berrío, J.C., Williams, J.W., 2007. Pollen methods and studies/Databases and their application. In: Elias, S.A. (Ed.), Encyclopedia of Quaternary Science. Elsevier, pp. 2521-2528.

3. Flantua, S.G.A., Hooghiemstra, H., Grimm, E.C., Behling, H., Bush, M.B., González-Arango, C., Gosling, W., Ledru, M.-P., Lozano-García, S., Maldonado, A., Prieto, A., Rull, V., Van Boxel, J.H., 2015. Updated site compilation of the Latin American pollen database. Rev. Palaeobot. Palynol. 223, 104-115.

4. Myers, N., Mittermeier, R.A., Mittermeier, C.G., da Fonseca, G.A.B., Kent, J., 2000. Biodiversity hotspots for conservations priorities. Nature 403, 853-858.

5. Koch, A., Brierley, C., Maslin, M.M., Lewis, S.L., 2019. Earth system impacts of the European arrival and great dying in the Americas after 1492. Quat. Sci. Rev. 207, 13-36.

6. Montoya, E., Lombardo, U., Aymard, G.A., Levis, C., ter Steege, H., Mayle, F.E., 2019. Human contribution to Amazonian diversity: pre-Columbian legacy to current plant communities. In: Rull, V., Carnaval, A. (Eds.), Neotropical Diversification. Springer, Berlin (in press).

Apply Now