Thursday, 2 June 2016

Reconstructing Wildlife Populations in East Africa (Mara Triangle, Kenya) using Faecal Sterol Chemistry...by Christopher Vane

Chris Vane collecing elephant
dung samples

Introduction

Over the last few years the Organic Geochemists at the British Geological Survey (BGS) have been successfully analysing human sourced faecal waste in UK soils and sediments in order to assess the extent of treatment, frequency of raw sewage pollution release and how this corresponds to pollutants and pathogens. One outcome of this work has been to show that sediments often contain distinct faecal chemical 'fingerprints' from other sources namely, domestic and wild animals (Vane et al., 2011)

The Big Idea

Long–term collaborators Chris Vane (BGS) and Andy Kemp (University Tufts) teamed up with Chris Dutton, University of Yale to explore the idea of whether the faecal sterols (a class of organic molecules) found in animal waste and disseminated in sediments could be used to reconstruct past wildlife populations in Africa. Understanding how wildlife populations have changed over long periods (1000 years) through time is an important conservation goal particularly in Kenya and Tanzania where safari tourism is an important source of income for local communities. External funding was sought and won to evaluate faecal matter from a range of key species with the long-term aim to then apply this information to sediment cores from watering holes.

Field Campaign

Our study area was, close to the Kenyan-Tanzanian border, we camped in woodland on the edge of the savannah enabling a daily collection campaign like no other.  Fortunately, we were in good hands with knowledge and logistical support from the Mara Conservancy who gave permission to explore most of the conservancy via land rover and supplied an armed ranger for the collection of fresh samples on foot.  The team tracked and collected fresh faecal samples from a huge variety of animals including, elephant, ostrich, hippopotamus, zebra, lion, giraffe, baboon, wildebeest, buffalo, topi, hyena, leopard, cheetah, warthog, crocodile as well as domestic cattle and sediments from the Mara and Talek rivers. In order to account for dietary and locational/migratory differences we sampled from multiple individuals and herds across the Mara conservancy.

A selection of the huge variety of animals that were tracked and fresh faecal samples collected from.
From L-R: Black back jackal, elephants, lions, giraffes, hyena. 

Faecal Sterol Database

Organic Geochemists at BGS, Drs Chris Vane, Alex Kim assisted by University of Nottingham placement student Katherine Edgley are currently (May-August 2016)  busy preparing, separating and measuring the concentrations of 14 different sterols using Gas-Chromatography-Mass Spectrometry, a technique used to analyse and quantify organic compounds. The aim of this was to build a database from which the wildlife populations of the past can be tracked even in disseminated sediments. Preliminary results look promising with clear differences between major species.
                                                               

References

Vane, C.H., Kim, A.W. McGowan, S., Leng, M.J., Heaton, T.H.E. Coombs, P. Kendrick, C.P., Yang, H., Swann, G.E.A.  2010. Sedimentary record of sewage pollution using faecal marker compounds in contrasting peri-urban shallow lakes. Science of the Total Environment 409, 345-356.

video

For up to date information about this on-going  project or other Organic Geochemical studies at BGS please contact Chris Vane (email chv@bgs.ac.uk). 





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