Martin Stoffel

 

Profile

Although Pinnipeds were hunted by humans since the stone age, commercial seal harvesting during the last three centuries brought many species to the edge of extinction. Some species managed to largely recover their population sizes (such as the northern elephant seal or the antarctic fur seal) and others have never been seen again. The overexploitation caused by commercial sealing lead to a substantial decrease in abundance, in the extreme case of the Northern Elephant Seal the population size dropped down to just a handful of individuals.

IMG_5630-1

Northern Elephant Seal pups

While population bottlenecks cause a considerable loss of genetic variation, the question remains whether the fitness of post-bottleneck generations suffers too. In addition, seals are often highly polygenous, whereby males guard and mate with large harems of females, which potentially slows down the recovery of genetic variation. It becomes clear, that avoiding inbreeding and maximising genetic variation is of fundamental importance to many seal species.

I am studying the effects of variation in genomic homozygosity (i.e. the proportion of genes that are identical by descent or IBD) on fitness traits and extended phenotypes (odour, bacterial communities) in Pinnipeds. Therefore, I´m using a range of genetic and genomic methods, from microsatellites to high throughput sequencing. For my most current project, I’m using Approximate Bayesian Computation to compare the impact of commercial hunting on 28 different seal species to estimate the probability of population bottlenecks and link these to ecological and demographical factors.

IMG_4670-1

Checking Elephant Seal IDs on the San Benito Archipelago

An important aspect of my work is R programming. Biology is evolving rapidly and changing towards a more open and data-intense science. The increasing complexity of both problems and methods in fields such as ecology and population genetics also requires a change in terms of transparency and reproducibility of analyses.

The R language provides the unique opportunity to easily document and publish code and develop packages for the scientific community, often simply as a byproduct of ongoing projects. At the moment I am one of the main authors of three scientific R packages on CRAN. (1) inbreedR provides a framework for the analysis of inbreeding and HFCs based on genetic marker data, such as SNPs and microsatellites. (2) Together with Holger Schielzeth and Shinichi Nakagawa I revised the rptR package, which provides methods for the estimation of raw variances, repeatabilities and marginal R2 within a mixed model framework. (3) The newest project together with Meinolf Ottensmann is GCalignR, a package to align data from gas-chromatography, which we developed to detect patterns in olfactory profiles of wild animal populations.

Outside of work,  I try to keep a harmony between my mind and body. I’m coming from a background in competitive swimming and still try to do all kinds of sports. Usually, I´m reading two or three books at a time (from which I rarely finish one to be honest) to keep an open mind about things apart from what I am doing on a daily basis. Besides that, I recently became a passionate touring cyclist and photographer with a special interest in wildlife and landscapes.


 Supervisors and Collaborators

Joe Hoffman, Bielefeld University, Germany
Hazel Nichols, Liverpool John Moores University, UK
Kanchon Dasmahapatra, University of York, UK
Karina Acevedo-Whitehouse, Autonomous  University of Queretaro
Holger Schielzeth, Dept. of Evolutionary Biology, Bielefeld University Germany
Mareike Esser, Dept. of Biomathematics and Theoretical Bioinformatics, Bielefeld University Germany


Education
  • 2012–2014:  M.Sc. Behaviour: From neural mechanisms to evolution – Bielefeld University (focus: ecology and neuroscience)
  • 2009–2012: B.Sc. Psychology – University of Koblenz-Landau
Publications

Articles

  • Stoffel, M.A., Nakagawa, S., Schielzeth, H. (2017).  rptR: Repeatability estimation and variance decomposition by generalized linear mixed-effects models. Methods in Ecology and Evolution. accepted. Here is the link to the package
  • Ottensmann, M.*, Stoffel, M. A.*, & Hoffman, J. I. (2017). GCalignR: An R package for aligning Gas-Chromatography data. bioRxiv, 110494. * Contributed equally. Here is the link to the package
  • Stoffel, M.A., Esser, M., Kardos, M., Humble, E., Nichols, H.J., David, P. & Hoffman, J.I..  inbreedR: An R package for the analysis of inbreeding based on genetic markers.  Methods in Ecology and Evolution. DOI: 10.1111/2041-210X.12588pdf Supplementary Information pdf Here is the link to the package.
  • Stoffel, M., Caspers, B.A., Forcada, J., Giannakara, A., Baier, M.C., Eberhart-Phillips, L.J., Müller, C. & Hoffman, J.I. (2015) Chemical fingerprints encode mother-offspring similarity, colony membership, relatedness and genetic quality in fur seals. Proceedings of the National Academy of Sciences of the United States of America., 112: E5005-E5012. Doi:10.1073/pnas.1506076112 pdf Supplementary Information pdf R code pdf Journal cover pdf Commentary article in PNAS pdf and JEB pdf
  • Stoffel M, Reis D, Schwarz D & Schröder A (2013). Dimensions of coping in Fibromyalgia patients: Factor analysis and cross-validation of the Coping Strategies Questionnaire (CSQ-D).Rehabilitation Psychology. PDF

Conference contributions

  • Stoffel, M., Caspers, B.A., Forcada, J., Giannakara, A., Baier, M.C., Eberhart-Phillips, L.J., Müller, C. & Hoffman, J.I. What a seal´s smell can tell – investigating the chemical basis of seal olfaction. Speed talk at the 22. Marine Mammal Biennial Conference, 2015, San Francisco. Slides: smm2015_talk_final.  (Award for the best pre-doctoral speed talk; travel grant)
  • Cesare V Parise, Martin Stoffel & Marc O Ernst (2014) Multisensory classification images reveal the role of cross-correlation in audiovisual temporal processing. Poster presented at the VSS conference, Florida.PDF
  • Stoffel, M., Reis, D., Schwarz, D. & Schröder, A. (2012). The influence of coping strategies on psychological stress in chronic pain patients. Poster presented at the German Congress of Psychosomatic Medicine and Psychotherapy, Munich.PDF 

Reviewing

  • Proceedings of the Royal Society B.

Press

Article in the Natural History Magazine, 2015
Article in the Daily Express, 2015
Article in the Süddeutsche Zeitung, 2015

sz_article_hp


Contact Details

Department of Animal Behaviour
Bielefeld University
Postfach 100131
33501 Bielefeld
Germany

School of Natural Sciences and Psychology
Liverpool John Moores University
Merseyside
UK
L3 3AF

email: martin.adam.stoffel[at]gmail.com
GitHub: mastoffel

 

I am funded by:

LJMU studentship

Genetics Society, Heredity Fieldwork Grant