The 2018 edition of the University of Amsterdam masters course “Environments Through Time” is now up and running. The course sits at the interface between ecology, physical geography and archaeology and seeks to provide students with a better understanding of how long-term (>100’s years) datasets can provide insights in to past environmental change.
In the first week of the course the students had to present their ‘favourite’ paper in just three (3) minutes! Quite a challenge and lots of fun. This years selection of papers themed around:
mega-fauna extinctions (Bakker et al., 2016; Gill et al., 2009; van der Kaars et al., 2017),
impacts of human land use practices (Bitusik et al., 2018; Carson et al., 2014; Chepstow-Lusty et al., 2009; Gauthier et al., 2010; Tisdall et al., 2018), and
climatic drivers of vegetation change (Haug et al., 2001; Tierney et al., 2017; Tudhope et al., 2001).
For full list of papers presented see below.
In the second and third weeks (now ongoing) students get to deconstruct published chronologies and conduct time series analsis of multi-proxy datasets. Data for these excercises is frequently is extracted from databases such as Neotoma, Pangea, NOAA – paleoclimatology datasets database and the Global Charcoal Database – which shows the importance of these open access databases for developing effective research led eductation, as well as pushing forward to frontiers of research.
Valencia 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.
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.
Nick and Will with Carman (director of the Pindo Mirador biological station)
Three members of the PCRG (William Gosling, Encarni Montoya and Nick Loughlin) visited Ecuador (November-December 2013) to develop collaborations with Ecuadorian institutions, recover more lake sediments, and find new potential sites for projects. Below are some photos from:
Lake Huila, and
Full reports on specific aspects of the fieldwork to follow.
Photo taken close by the study site. The road that pass through Eastern Andes, and the magnificent Montane forest of western Amazonia behind. (Photo by M. L. Cárdenas)
Who would have thought that building a road in Andes would have allowed us to gain new and unique insight of pristine western- Amazonian forests? (I would have thought completely the opposite). Initially Patricia Mothes, chief of the volcanologist section of the Intituto de Geofisica in Ecuador, was called to look at sediments exposed by road works on the eastern flank of the Ecuadorian Andes. Arriving at the site she found thick (>20 vertical meters) deposits of grayish and dark brown interbedded layers of sediments which looked like they have been recently deposited. At closer inspection Patricia discovered that there were even wood pieces and leaves within the dark sediments (now known to be highly organic) that had the appearance of have been deposited within modern time. She wanted to know more. So a PhD student was recruited (a.k.a. Macarena Cárdenas) to work with the sediments at the Palaeoenvironmental Change Research Group at the Open University under the supervision of Dr William Gosling… And so the study began.
After several years spent dating the sediments, analyzing their composition (physical and elemental) and the fossils (pollen and wood) contained within them preliminary insights into vegetation change on the eastern Andean flank during the middle Pleistocene (c. 200,000-300,000 years ago) were revealed and published (Cárdenas et al., 2011a; Cárdenas et al., 2011b). Further work covering stratigraphically lower sediments (older than those previously published; c. 500,000 year) and more detailed sedimentary and fossil analysis of the entire sequence completed a PhD thesis (Cárdenas, 2011).
I am now pleased to announce that the extended work included in my PhD thesis has now been published in a new article in Palaeogeography, Palaeoclimatology, Palaeoecology (Cárdenas et al., online). The new paper is an extended version from previous publications from the same research and provides further evidence of the unique insights that can be gained from palaeoenvironmental studies in this region. These are some of the oldest Quaternary sediments ever discovered and studied from the mid-elevation eastern Andean flank / western Amazon and upon their analyses we were able to get for the first time an insight of how human-untouched Amazonian forests were back in time (up to 500,000 years ago!), how was their diversity and how they responded to intense volcanic activity and climatic change.
By Dr Macarena L. Cárdenas
Cárdenas, M.L. (2011) The response of western Amazonian vegetation to fire and climate change: A palaeoecological study. In: Department of Earth & Environmental Sciences, p. 242. The Open University, Milton Keynes
Cárdenas, M.L., Gosling, W.D., Pennington, R.T., Poole, I., Sherlock, S.C. & Mothes, P. (online) Forests of the tropical eastern andean flank during the middle pleistocene. Palaeogeography, Palaeoclimatology, Palaeoecology. DOI:10.1016/j.palaeo.2013.10.009
Cárdenas, M.L., Gosling, W.D., Sherlock, S.C., Poole, I., Pennington, R.T. & Mothes, P. (2011a) The response of vegetation on the Andean flank in western Amazonia to Pleistocene climate change. Science, 331, 1055-1058. DOI: 10.1126/science.1197947
Cárdenas, M.L., Gosling, W.D., Sherlock, S.C., Poole, I., Pennington, R.T. & Mothes, P. (2011b) Response to comment on “the response of vegetation on the Andean flank in western Amazonia to Pleistocene climate change”. Science, 333, 1825. DOI: 10.1126/science.1207888
Understanding how vegetation responded to past climate change requires the development of well constrained relationships between living floras, environment and climate. This project will help constrain the great uncertainty which exists as to how tropical ecosystems are represented in the fossil record by examining the relationship between modern vegetation and the pollen it produces. The project will analyse modern pollen rain using a combination of traditional microscopic analysis  and cutting edge geochemical techniques . We anticipate that the findings will provide new insight into past vegetation and climatic change.
For further information on the project and how to apply see the full advert: NERC PhD advert. Prior to applying please check eligibility for NERC funding by clicking here.
Closing date: 25th April, interviews will be held at The Open University during May.
Two NERC algorithm funded PhD studentships are currently available with the PCRG. The projects are focused on understanding past environmental change in west tropical Africa and Amazonian-Andean Ecuador. Both projects will involve field work and build on on-going research within the lab.
Closing date 31/01/2013
One project will work on samples collected during fieldwork in 2012 near Papallacta (Ecuador).
One of the key goals of the fieldtrip to Ecuador (August-September) was to sample organic and volcanic (tephra) layers from sedimentary exposures with the aim of obtaining new information about past envrionmental change in the region. Our Ecuadorian collaborator, Dr Patricia Mothes (Instituto Geofisico), had identified four of sites she thought might be useful too us: El Fatima Dique, Mera “2” Dique, El Rosol and Vinillos.
At the Fatima site, near Puyo, a thin organic bed was sampled sandwiched between volcanic ash deposits. Wood macrofossils from this deposit have been dated to the last glacial period.
For further descriptions of what we found and field photos read on…