Montoya, E., Keen, H.F., Luzuriaga, C.X. & Gosling, W.D. (2018) Long-term vegetation dynamics in a megadiverse hotspot: The Ice-Age record of a pre-montane forest of central Ecuador. Frontiers in Plant Science 9, 196. doi: 10.3389/fpls.2018.00196
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.
We’ve got a bumper crop of palaeoecological film making for you today, with three videos uploaded to our very own ‘Ecology of the Past’ Youtube channel. We’ve got an interview with Will Gosling, talking about the Bosumtwi pollen chemistry project and his own background and career (it’s a timely and somewhat poignant addition to the channel, because this is Will’s last day at The Open University before heading off to Amsterdam). Also posted are research presentations by Frazer Bird and Hayley Keen, which were filmed during the PhD student conference on 21st May. For the first time at the Open University these presentations were carried out in the Three Minute Thesis (3MT®) format.
Last month I had the opportunity of attending the 3-days non-pollen palynomorphs (NPP) workshop that was held at the Tallinn University, Estonia. It was perfectly organised by Tiiu Koff and Egle Avi among other members of the university, as it was a join workshop of Cladocera remains (XII Subfossil Cladocera workshop; 16-18th June) and NPP (18-20th June). Unfortunately, I was just present in the NPP workshop, so my comments will be focus on it.
With around 40 participants, we greatly enjoyed the discussions that came up about the state-of-the-art of this broad and interesting proxy and its implications for archaeology, palaeolimnology, and different aspects of ecology like human landscape management, biodiversity and conservation, or community assemblages. Current methodological problems like taxonomy, standardisation of lab techniques, etc., were also debated.
Opening and key lectures were from Bas van Geel and Emilie Gauthier, showing the development of this discipline over the last 40 years, and a great example of multi-proxy project aimed to study the human arrival and impact in Greenland respectively. Besides oral and poster presentations, last day there was a microscope session, very useful for sharing knowledge and uncertainties! In our specific case, Will, Hayley and I contributed with a poster titled “Non-pollen palynomorphs in Ecuador: starting from scratch”.
Personally, among the things I most like from the NPP meetings is the friendly and close environment, where everyone is more than glad to help others, regardless the experience. Following this feeling of small and scattered group of people dealing with the same issues, we used to do a final remark session every workshop raising the advances and inconveniences found so far, updating our NPP papers repository (managed by Antonella Miola), and addressing future directions as a group (for instance, we have now our own project in ResearchGate, thanks to Lyudmila Shumilovskikh!). In this particular workshop, I was very happy when I found out that Tallinn University has a green policy (paper free), and they replaced book abstracts etc., by iPads to follow the workshop schedule.
Although these meetings are normally biannual, next conference location and date is yet to be decided, but we hope to have the chance to join this very friendly and supporting community again. In addition, there will be a NPP session in the next European Palaeobotany and Palynology congress, tobe held in University of Padova (Italy), next August 2014. We encourage people with all kind of experience (or lack of) to attend further events.
Heslop-Harrison, J. (1979) Aspects of the structure, cytochemistry and germination of the pollen of Rye (Secale cereale L.). Annals of Botany, 44, 1-47.
Summary (Adele): Sometimes, the old ones are the best, and this behemoth of a paper contains a huge amount of useful information on the chemical structure and development of Rye pollen grains. As I am working on the chemistry of grass pollen at the moment, it is incredibly useful to know that this sort of information exists and can be used to inform both my experimental protocol and interpretations.
SUMMARY (Will): People have long been concerned about environmental change. Observations of phenological shifts, degradation of ecosystem services and climate change are clearly presented in Checkhov’s “The Pipe” (1889).The key difference is today we have a better idea of why these things are happening!?
Garcia, R.A., Cabeza, M., Rahbek, C. & Araújo, M.B. (2014) Multiple dimensions of climate change and their implications for biodiversity. Science 344 1247579
SUMMARY (Phil): This review highlights the alternative metrics used to quantify climate change at different spatial scales, each with its own set of threats and opportunities for biodiversity. It’s a very relevant paper for palaeoecologists, with implications for how we think about climatic estimates we generate, how we interpret ecological shifts in the assemblages we study, and for demonstrating the importance thinking spatially as well as temporally. It also shows how important palaeoecological data is for setting baselines and putting projected climatic change into context.
Stansell, N.D., Polissar, P.J., Abbott, M.B., Bezada, M., Steinmann, B.A. and Braun, C. (2014) Proglacial lake sediment records reveal Holocene climate changes in the Venezuelan Andes. Quaternary Science Reviews. 89, 44 – 55.
SUMMARY (Hayley): A study of three lake sediment records in the Venezuelan Andes to look at patterns of glacial variability, and how glaciers might have responded to changing climatic conditions during the last c. 12,000 years.
Still, C.J., Foster, P.N. & Schneider, S.H. (1999) Simulating the effects of climate change on tropical montane cloud forests. Nature, 398, 608–610.
SUMMARY (Nick): The paper attempts to model the impact of climate change on a number of cloud forests around the world by simulating atmospheric parameters at the last glacial maximum (LGM) and at twice today’s CO2 level. The models agrees with palaeoecological data of a downslope migration of the cloud forest at the LGM, while the 2xCO2 model shows reduced cloud cover and increased evapotranspiration, which results in a significant reduction in cloud forest supporting land area.