Polylepis woodland dynamics during the last 20,000 years

March 23, 2018
WDG

Valencia, B.G., Bush, M.B., Coe, A.L., Elizabeth, O. & Gosling, W.D. (2018) Polylepis woodland dynamics during the last 20,000 years. Journal of Biogeography online. DOI: 10.1111/jbi.13209

An undergraduate eye-view of an Andean lake-coring expedition

August 23, 2017
WDG

Part 1: Huayabamba
by Molly Kingston (a BSc Biological Sciences student at Florida Institute of Technology, taking part in an expedition lead by Prof. Mark Bush)

When I first heard about this class in Peru, I had no idea that I was going to experience so much in such a short period. Our goal was to visit two lakes in Peru and raise sediment cores for paleoecology. The first lake that we went to was Laguna Huayabamba, which sits at about 3250 m elevation in the La Libertad region of the Peruvian Andes.

However, getting to this lake was no easy task. Before the hike even started, we had to obtain the necessary permits and permission from the local people. After several days of visiting different town officials and waiting for approval, we could set out on our adventure.

Continue Reading

British Ecological Society annual meeting 2016

December 15, 2016
WDG

bes_new_logo_2016The British Ecological Society (BES) annual meeting for 2016 has come to an end. It has seemed like a long week (and it is only Thursday) because it has been so action packed. For me it commenced on Sunday when I helped out with the introduction session for early career researchers (MSc, PhD and post-docs), and the marathon council meeting. I think the length, and intensity, of the council meeting highlighted the need for the structural review that our president, Sue Hartley, has just initiated. The main program commenced on Monday and has been mainly a mix of workshops, posters and talks, with a side order of special interest group meetings, carol singers, and a gala dinner.
I would like to highlight two of the scientific talks that stuck in my head in particular:

  1. Steven Sylvester “Shifting perspectives on natural ecosystems in the high Andes”; showed how remote regions of the high Andes may still contain the vestigaes of ‘pristine’ ecosystems dating from before human arrival, and
  2. Stefano Allesina “Higher-order interactions stabilize dynamics in a generalized rock-paper-scissors game”; showed (theoretically) how ecosystem complexity plays a role in ecosystem stability.

Nick-thumbAn excellent and exciting meeting was capped for me by my PhD student Nick Loughlin for being awarded the BES Public Engagement award! Well done Nick (@PalaeoNick).

REFERENCES

Sylvester, S.P., Sylvester, M.D.P.V. & Kessler, M. (2014) Inaccessible ledges as refuges for the natural vegetation of the high Andes. Journal of Vegetation Science 25, 1225-1234. DOI: 10.1111/jvs.12176

 

Valencia PhD thesis 2014

March 5, 2015
WDG

Bryan-Kuelap-gate-2010-smallValencia Castillo, B.G. (2014) From glacial to modern conditions: Vegetation and climate change under human influence in the Central Andes. PhD Thesis, Department of Environment, Earth & Ecosystems, The Open University.

Abstract
Conservation, restoration and management strategies are employed to maintain Earth’s biological diversity and physical environment to a near “natural” state. However, the concept of “natural” is generally inexact and may include degraded landscapes. In absence of long-term empirical data of natural baselines, impacted assemblages (human altered baselines) could be falsely assumed to be natural and set as conservation or restoration goals. Therefore, the identification of long-term ecological baselines becomes a pressing requirement especially in threatened biodiversity hotspots such as the tropical Andes that were under human pressure for several millennial.

This thesis aims to identify ecological baselines for tropical Andean ecosystems based on multi-proxy palaeoecological reconstructions from three Andean lakes. Trends of vegetation change are used to identify when landscapes became anthropogenic in the Andes. Because vegetation assemblages at c. 10 ka experienced negligible anthropogenic impacts and had modern-like climate condition, this time was considered the most recent period likely to provide insight into natural ecological baseline conditions.

Changes in vegetation assemblages were evaluated over time departing from 10 ka around Miski and Huamanmarca, two sites that remained virtually impervious to human impacts. Baselines in Miski and Huamanmarca drifted continuously over time and showed that baselines are dynamic entities. The vegetation assemblages derived from Miski and Huamanmarca suggest that that human impact was not homogeneous throughout the Andean landscape.

Once baselines were defined it was possible to evaluate if the spatial distribution of Andean woodlands represented by Polylepis was a product of human impacts. A MaxEnt model generated based on 22 modern environmental variables and 13 palaeoecological vegetation reconstructions showed that Polylepis woodlands were naturally fragmented before humans arrived in South America (14 ka). However, the influence of humans during the mid and late Holocene enhanced the patchiness of the forest generating a hyper-fragmented landscape.

Supervisors: Dr. William D. Gosling , Dr. Angela L. Coe (both The Open University) and Prof. Mark B. Bush (Florida Institute of Technology).

Examined by: Dr. Robert Marchant (University of York), and Prof. David Gowing (The Open University).

To borrow a copy from The Open University Library click here.

Media articles

Relics discovered in Mexico’s Teotihuacan, BBC News

Tree of the year finalists announced, BBC News

Journal articles

Kessler, M., Toivonen, J.M., Sylvester, S.P., Kluge, J. & Hertel, D. (2014) Elevational patterns of Polylepis tree height (Rosaceae) in the high Andes of Peru: role of human impact and climatic conditions. Frontiers in Plant Science: Functional Plant Ecology 5, Article 194.

Sylvester, S.P., Sylvester, M.D.P.V. & Kessler, M. (2014) Inaccessible ledges as refuges for the natural vegetation of the high Andes. Journal of Vegetation Science 25, 1225-1234.

Keller, A., Danner, N., Grimmer, G., Ankenbrand, M., von der Ohe, K., von der Ohe, W., Rost, S., Härtel, S. & Steffan-Dewenter, I. (2014) Evaluating multiplexed next-generation sequencing as a method in palynology for mixed pollen samples. Plant Biology online.

Williams PhD thesis 2011

May 13, 2014
WDG

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)

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.

Continue Reading

Ecosystem service provision sets the pace for pre-Hispanic societal development in the central Andes

July 31, 2013
WDG

Water resources in the Vacas region (near Cochabamba, Bolivia) deminished around the time of the founding of the urban centre at Tiawanaku

Water resources in the Vacas region (near Cochabamba, Bolivia) deminished around the time of the founding of the urban centre at Tiawanaku

Gosling, W.D. & Williams, J.J. (2013) Ecosystem service provision sets the pace for pre-Hispanic societal development in the central Andes. The Holocene, 23(11): 1617-1622. doi: 10.1177/0959683613496296

Click here to download an open access version of this manuscript via The Open University Open Reseach Online repository.

Blog at WordPress.com.