Vegetation responses to late Holocene climate changes in an Andean forest By Klaas Land (currently studying MSc Biological Sciences (Ecology & Evolution) at the University of Amsterdam.
The discussion during the APC meeting on the 19th of March was on the paper by Schiferl et al. (2018), a very recent study on the climatic shifts in the late Holocene and their effects on the South American tropics. The study had analysed a core going back about 3800 years from Lake Palotoa, which was in the Andean foothills (1370m elevation). They found that subtle changes to the fossil pollen record could be identified around the estimated periods for the Little Ice Age (LIA) and Medieval Climate Anomaly (MCA). The focus in the paper Continue Reading
Gosling, W.D., Cornelissen, H. & McMichael, C.N.H. (2019) Reconstructing past fire temperatures from ancient charcoal material. Palaeogeography, Palaeoclimatology, Palaeoecology520, 128-137. DOI: 10.1016/j.palaeo.2019.01.029
The montane cloud forests of South America are some of the most biodiverse habitats in the world, whilst also being especially vulnerable to climate change and human disturbance.
Today much of this landscape has been transformed into a mosaic of secondary forest and agricultural fields. This thesis uses palaeoecological proxies (pollen, non-pollen palynomorphs, charcoal, organic content) to interpret ecosystem dynamics during the late Quaternary, unravelling the vegetation history of the landscape and the relationship between people and the montane cloud forest of the eastern Andean flank of Ecuador. Two new sedimentary records are examined from the montane forest adjacent to the Río Cosanga (Vinillos) and in the Quijos Valley (Huila). These sites characterise the natural dynamics of a pre-human arrival montane forest and reveal how vegetation responded during historical changes in local human populations.
Non-pollen palynomorphs (NPPs) are employed in a novel approach to analyse a forest cover gradient across these sites. The analysis identifies a distinctive NPP assemblage connected to low forest cover and increased regional burning. Investigation into the late Pleistocene Vinillos sediments show volcanic activity to be the primary landscape-scale driver of ecosystem dynamics prior to human arrival, influencing montane forest populations but having little effect on vegetation composition.
Lake sediments at Huila from the last 700 years indicate the presence of pre-Hispanic peoples, managing and cultivating an open landscape. The subsequent colonization of the region by Europeans in the late 1500’s decimated the indigenous population, leading to the abandonment of the region in conjunction with an expansion in forest cover ca. 1588 CE. After approximately 130 years of vegetation recovery, montane cloud forest reached a stage of structural maturity comparable to that seen in the pre-human arrival forest. The following 100 years (1718-1822 CE) of low human population and minimal human impact in the region is proposed as a shifted ecological baseline for future restoration and conservation goals. This ‘cultural ecological baseline’ features a landscape that retains many of the ecosystem service provided by a pristine montane forest, while retaining the cultural history of its indigenous people within the vegetation. Continue Reading
Veerle and I trying to protect ourselves from the mosquitos.
My name is Britte Heijink and I’m doing my MSc Biological Science thesis research project with Crystal McMichael and William Gosling. I travelled with Veerle Vink and Crystal to the Colombian part of Amazonia to collect samples for my project. At Amacayacu National Park, we collected soil cores from different locations in the plot. Now that we’re back in Amsterdam, I’m analysing the soils to reconstruct the fire and vegetation history from the plot using charcoal and phytoliths. I am specifically looking to see if humans have been present in the system and how they potentially affected the vegetation at Amacayacu.
Here I’m Sampling pieces of soil cored by Louisa and checking for large pieces of charcoal
I’ve completed my bachelor thesis for Bèta-Gamma (Liberal Arts and Sciences) under the supervision of Crystal and Will here at the UvA. I’m really excited to work with them again, and already looking forward to our meetings at the Oerknal 😉 I will be finished by the end of September, and then possibly return for a literature study.
One of the most wonderful experiences in my academic career so far has been the fieldwork to Panama and Colombia with Crystal, Veerle, and Nina. It was a lot of hard work, and 90% of our time was spent covered in mud, sweat, and insect repellant, but the experience of working in a tropical rainforest was completely worth it! Veerle and I will write another blog about our fieldwork soon. Come see us in the microscope lab if you want to hear our dangerous and amazing stories before that!
Our last day in the Amazon was spend with some of the local students, Louisa Fernando Gomez Correa and Mariana Gutierrez Munera.
Each project was set up to test a particular ecological or biogeographic hypothesis. Investigations included the exploration of the role of humans in modifying ecosystems in Amazon, the nature of the pre-farming landscape in the the Netherlands, and how to chemically identify fossil charcoal. In undertaking their projects individual students had the opportunity to variously develop skills in microscopy, spatial modelling, or analytical chemistry. The high quality of the data produced means that hopefully many of these data sets can be used in future scientific publications. Well done to all!
If you are interested in conducting a similar project (at any academic level) with us please do not hesitate to get in contact. For further details of ongoing research within the Department of Ecosystems & Landscape Dynamics visit our web pages by clicking here.
Past environmental change on Mauritius has been the focus of research with the Palaeoecology & Landscape Ecology group at the University of Amsterdam (UvA) for a number of years. This research has been lead by Erik de Boer and Henry Hooghiemstra and has already resulted in a number of key publications on the environmental history of the island (de Boer et al., 2013, 2014, 2015). One current past environmental change research project working on Mauritius is being undertaken by Jona de Krui; a student within the UvA BSc Biology program supervised by myself and Erik. Jona’s is working on a study site (modern day swamp) on the north-east of the island and is focused on improving our understanding changes in the:
vegetation (macro-fossils) over the last c. 1000 years.
Jona has now completed the analysis of all his samples and we are currently collating the data sets; however, a number of the macro-fossils which he has discovered remain unidentified. Below are images of the unknown macro-fossils if you have any suggestions on identifications please comment, or get in touch directly.
Hayley Keen getting excited about sediments during fieldwork in Ecuador (2012). Photo: J. Malley
Keen, H.F. (2015) Past environmental change on the eastern Andean flank, Ecuador. PhD Thesis, Department of Environment, Earth & Ecosystems, The Open University.
Abstract The eastern Andean flank of Ecuador (EAF) contains some of the world’s most biodiverse ecosystems. Andean montane forests are threatened due to anthropogenic pressures and both current and projected climate change. This thesis examines the palaeoecological history of two stratigraphic sequences (Mera Tigre West [MTW] and Mera Tigre East [MTE]) obtained from the Ecuadorian modern lower montane forest. The sediments preserved were analysed using eight analytical techniques, allowing an insight into the ecosystem’s potential response to projected changes derived from their past responses. Palaeoecological studies on the EAF are rare, and those that do exist are debated relating to: i) the inference of robust ecological data from pollen records in floristically diverse locations, and ii) the past source area of sediments preserved in fluvially exposed sequences, potentially leading to contamination with older material.
A statistical sub-sampling tool was developed (debate i), capable of producing statistically robust count sizes for each pollen sample; MTW and MTE count sizes ranged from 196-982 showing the diversity within sequences. The depositional environment of MTE was analysed, investigating sediment provenance throughout (debate ii). Results found that large scale volcanic events were critical in the preservation of the sediments, whereas fluvial influence caused a regional sediment source area in the upper stratigraphy, impacting on the palynological interpretation of MTE. Pollen records demonstrated the presence of a diverse vegetation community with no modern analogue at MTE (abundant taxa (>15 %): Hedyosmum, Wettinia, Ilex) and upper montane forest at MTW (Alnus, Hedyosmum, Podocarpus). Fire was not the main driver for the vegetation reassortment at either site (MTW correlation coefficient: -0.37, MTE: 0.16). The two sites have demonstrated the EAF plays host to floristically dynamic ecosystems, susceptible to drivers of change (fire and landscape) and should be considered when predicting the montane forests’ future response to environmental change.