On Tuesday the UK participation in the International Continental scientific Drilling Program (ICDP) was officially launched at the British Geological Survey (Keyworth). The ICDP is designed to help scientists with the aquisition of samples to answer fundemental questions related to geological and enviornmental science. Now that the UK has membership to the ICDP, thanks to investment from the BGS, UK based scientists can take more of a lead in developing projects. Having worked on two projects based on ICDP sediments (Lake’s Titicaca and Bosumtwi) I am delighted by this development and hope over the next few years to be able to get involved in further exciting research.
I am delighted to report that Dr Encarnacion Montoya Romo (currently of the Botanical Institute of Barcelona) has been awarded a NERC Fellowship to join the PCRG. The project is entitled “Evaluation of tropical forests sensitivity to past climate change” (FORSENS) and will examine environmental change at four study sites from different regions of the Neotropics: 1) Khomer Kotcha (Bolivia; 17oS, 4100 m above sea level [asl]) [1-3], 2) Consuelo (Peru, 13oS; 1400 m asl) [4-5], 3) Banos (Ecuador; 0oS, 4000 m asl), and 4) a new lowland site from Columbia/Ecuador to be collected during field work during the project.
I have been engaged with two major activities during June: 1) submission of a research proposal to NERC, and 2) excitement of my first online teaching module going live to students, Cyprus activity, within Practical science: Earth and environment module (SXG288). Other members of the group have been writing up methods chapters (Natalie), number crunching and submitting abstract to the International Paleolimnology Symposium (Lottie), and submitting first year probation reports (Hayley and Frazer).
The course provided an introduction to the methods, guidance as to when to use the techniques and then outlined the assumptions, limitations and strengths of the various methods. The need to fully understand the techniques applied before attempting to critically evaluate the results was also strongly emphasised.
The course consisted of lectures covering measures of dispersion, cluster analysis, dendrograms, regression analysis, tree models, gradient analysis, transfer functions, time series and hypothesis testing. Afternoon practical computer classes involved using R, C2 and CANOCO to implement the various techniques covered in the lectures.
Overall the course was a great introduction to statistical analysis which I would certainly recommend for anybody working with complex and noisy datasets. In the next few days I will be using my newly learnt R skills to run indirect gradient analysis such as PCA, CA, DCA and NMDSCAL to search for environmental gradients within my data.
Numerical Analysis of Biological and Environmental Data training couse is an annual event and was held at UCL, on 14-25th May 2012. For more information about the course see Gavin’s website or read his blog From the bottom of the heap.
Time seemed to escape me in April so I have a lot of research group action to report in this post! Here are some highlights…
At The Open University (OU) the research students have all been busy (of course): Natalie presented her 3rd year talk at the CEPSAR student conference and attended a meeting in Durham, Lottie spent two weeks at University College London (Environmental Change Research Centre) learning to become a statistics guru studying the “Numerical Analysis of Biological and Environmental Data” course, while Hayley and Frazer have been writing up their first year probation reports ahead of their mini-vivas next month. Over in Florida Bryan submitted his first PhD paper and has headed off on field work in Peru; and most significantly… I am very pleased to report that Nikki successfully defended her PhD thesis! Congratulations Nikki!
Thinking of PhD I was also pleased to have the opportunity to welcome my PhD supervisor, Frank Mayle, to The OU to give a CEPSAR seminar last week. It was great to be able to show off the labs to Frank at last having promised to invite him down when I arrived at The OU in 2005! He gave a very interesting talk on new archaeological findings from beneath the rain-forest in the Amazon Basin.
Away from The OU a couple of weeks ago I was down at Charles Darwin House for the British Ecological Society meetings committee meeting! We were working on the program for the annual meeting in Birmingham during December this year and it is shaping up to be a very exciting event; keep up to date by following the BES on twitter (@BritishEcolSoc).
Abstract Amazonia has long been considered to be a pristine wilderness, largely untouched by human activity, supporting small, scattered indigenous tribes living in harmony with their rainforest environment.
However, recent discoveries of massive geometric earthworks, revealed by deforestation in recent decades, are challenging this ‘virgin wilderness’ paradigm and pointing to substantially greater environmental impacts by pre-Columbian societies than previously supposed.
In my talk I review these archaeological discoveries and discuss how a combined palaeoecological-archaeological approach has the potential to resolve the scale of environmental land use and disturbance associated with these ancient cultures. I also consider the implications of these findings for understanding rainforest ecology and biodiversity, as well as conservation policy.
If you are external to The Open University and wish to attend this lecture please contact William Gosling in advance.
CHIRONOMIDAE AS A PALAEO-ECOLOGICAL TOOL
Chironomidae is a family of two-winged flies more commonly referred to as non biting midges. This diverse group of insects have been known for a long time to be sensitive environmental indicators. Early research in the field showed that the trophic status of lakes could be classified according to the characteristic chironomid assemblages found within them (Thienemann, 1922). Furthermore the head capsules of the larvae are well preserved within the sedimentary record. As a result palaeolimnological researchers became increasingly interested in the potential for using Chironomids to track the trophic development of a lake through time by examining the changing assemblages within the accumulated sediments. With geographically close lakes displaying significantly different midge faunas the potential for the insects being used as climatic indicators was dismissed and the following hypothesis became established: Chironomid assemblage composition reflects in-lake variables, e.g. lake depth, pH, dissolved oxygen, trophic status and substrate. However work by Walker and Matthews (1989) demonstrated that temperature was by far the most significant variable in controlling the broad scale distribution and abundance of midge fauna.
Walker and Matthews realised the potential for the non biting midge to be used as a palaeoclimatic indicator from two initial observations. Firstly within the fossil records, as climate began warming following the deglaciation of the northern hemisphere, the relative abundance of taxa associated with cold oligotrophic lakes (Heterotrissocladius) abruptly declined. Secondly they noticed the best analogues for late glacial assemblages were found in modern day arctic and alpine settings. Overall Walker and Matthews concluded that the northern limit of temperate taxon was controlled by cold summer air and/or water temperatures. The southern limit of Arctic species was instead driven by cold oxygenated refugia in the profundal zone of deep, temperate lakes. These temperatures were significant with respect to the insect’s life cycles as many species require critical temperature thresholds to complete pupation and emergence stages.
Since the pioneering work of Walker and Matthews (1989) and others the debate linking Chironomids to temperature has raged. Debate has centred upon what controls chironomid distribution and how suitable, if at all, the insects are in the context of palaeoecological studies. Recently Velle et al. (2010) discussed some key factors which must be considered when working on chironomid based temperature resonstructions.
Below I present some of the debate around the midge-environment-temperature debate; focusing on both midge distribution and identification and the potential of this proxy as a indicator of past environmental and climatic change.