skip to primary navigation skip to content

Jan Laurens Geffert

Jan Laurens Geffert

Graduate student

My research is focusing on the improvement of range map methodologies for marine species. This involves the transfer of species mapping approaches from the terrestrial to the marine realm, attributing for sampling bias in species occurrence data to quantify model uncertainty, and possibilities to integrate expert knowledge into modelling approaches.



  • 2012 – present: Graduate student, Department of Geography, University of Cambridge & UNEP World Conservation Monitoring Centre, Marine Assessment and Decision Support
  • 2011 – 2012: Carlo Schmid Fellow at UNEP World Conservation Monitoring Centre, Species Programme
  • 2009 – 2011: Scientific research assistant at Nees Institute for Biodiversity of Plants, Bonn University, Germany
  • 2004 – 2011: Diplom in Biology, Geography and Conservation, Bonn University, Germany

Funding and awards (selection)

  • 2012 – 2015: Nippon Foundation Nereus Fellowship
  • 2012: International Consortium of Universities for the Study of Biodiversity and the Environment (iCUBE), Brunei: Graduate student stipend
  • 2011 – 2012: Carlo Schmidt Fellowship
  • 2010: Right Livelihood College junior scientist


This work is part of the Nereus Program, funded by the Nippon Foundation, and is carried out in close collaboration with the United Nations Environment Programme World Conservation Monitoring Centre (UNEP WCMC), Marine Assessment and Decision Support Programme.

Species range maps are a central perquisite for the management, conservation, and sustainable use of natural resources. However, our knowledge on the distribution of many species is still poor, especially in the marine realm. Species distribution modelling (SDM) is a valuable tool to overcome these data deficiencies and derive accurate range map predictions.

The central assumption in SDM is that a species' geographic distribution is determined by environmental factors. Each species requires specific environmental conditions in order to survive and successfully reproduce. These requirements make up the ecological niche of a species and also shape its geographic distribution. In empirical SDM, species records are used together with environmental variables of particular relevance for the given species to estimate its ecological niche. The niche is then projected back into geographic space to infer the actual range.

Species data can either be presence-absence data or presence-only data. However because it is difficult to obtain true absence data at large spatial scales and coarse sampling resolution, many macroecological models commonly employ opportunistically collected presence-only data. Large quantities of georeferenced species records are available via global relational databases, such as the Ocean Biogeographic Information System (OBIS). Yet, these data are often biased because of undersampling in certain regions or missing environmental representation across the study area, with most records stemming from the coastal zone, surface waters, and the northern hemisphere.

So far few models explicitly include sampling effort, although spatially explicit proxy data for taxonomic inventory completeness does exist. Including this information and weighting spatial predictions according to our knowledge on areas of predicted occurrence could significantly improve model performance.

Presence-only models frequently use "pseudo-absences", random points used to contrast suitable against unsuitable environmental conditions. Some authors have argued for environmentally or geographically stratified random samples of pseudo-absences. Stratifying pseudo-absences by sampling completeness could be a way to include a measure of uncertainty in the modelling approach and would potentially reduce the influence of sampling intensity on range map predictions.


Journal Articles

  • Geffert, J.L. & J. Mutke (in prep): Moss floristic kingdoms inferred from species inventory data.
  • Geffert, J.L.; Frahm, J.-P.; Barthlott, W. & J. Mutke (2013) Global moss diversity: spatial and taxonomic patterns of species richness. Journal of Bryology, 35 (1): 1-11. link
  • Mutke, J. & J.L. Geffert (2010) Keep on working: The uneven documentation of regional moss floras. Tropical Bryology, 31: 7-13. link

Posters and Presentations

  • Geffert, J.L. (2012): Mapping plant diversity across the scales. Talk at the ecology lunchtime lecture series, Zoology Department, University of Cambridge, Cambridge, UK. 30th March 2012.
  • Geffert, J.L. (2012): Biodiversity, Biogeography and Conservation of Cacti: Spatial Conservation Planning at Continental Scale. Poster at the student conference on conservation science, Zoology Department, University of Cambridge, Cambridge, UK. 20th – 22nd March 2012.
  • Geffert, J.L. (2012): Global patterns of moss biodiversity. Talk at the International Consortium of Universities for the Study of Biodiversity and the Environment (iCUBE) workshop 2012: Impact of Climate Change & Innovations for a Sustainable Future, Institute for Leadership, Innovation and Advancement (ILIA), Universiti Brunei Darussalam, Brunei Darussalam. 10th January 2012.
  • Mutke, J.; Korotkova, N.; Burstedde, K.; Stein, A.; Geffert, J.L. & W. Barthlott (2011): Biogeography and Biodiversity of Cacti. Poster at the 5th International Conference of the International Biogeography Society, Heraklion, Crete, 7th - 11th January 2011.

Policy documents

  • Martin C.S., Fletcher R., Jones M.C., Kaschner K., Sullivan E., Tittensor D.P., Mcowen C., Geffert J.L., van Bochove J.W., Thomas H., Blyth S., Ravillious C., Tolley M., Stanwell-Smith D. (2014). Manual of marine and coastal datasets of biodiversity importance. May 2014 release. Cambridge (UK): UNEP World Conservation Monitoring Centre. 28 pp. (+ 4 annexes totalling 174 pp. and one e-supplement)
  • IUCN (2012) Consolidating the Standards for Identifying Sites that Contribute Significantly to the Global Persistence of Biodiversity: The Results of a Framing Workshop. Cambridge, UK, 5–8 Jun 2012. Species Survival Commission and World Commission on Protected Areas, International Union for Conservation of Nature, Gland, Switzerland.
  • UNEP-WCMC (2012): Balearica pavonina, in: Review of Significant Trade: Species selected by the CITES Animals Committee following CoP14 and retained in the review following AC25. CITES Project No. S-380.
  • UNEP-WCMC (2012): Review of the Arabian Oryx (Oryx leucoryx Pallas) - Range and population in Oman. Impact assessment in UNEP-WCMC Business and Biodiversity Programme.
  • IUCN, UNCCD and UNEP-WCMC (2012) Conserving Dryland Biodiversity. IUCN Drylands Initiative, Nairobi, Kenya. ISBN 978-2-8317-1541-4, available from
  • UNEP-WCMC (2012) Coral species, synonyms, and nomenclature references currently recognized in the UNEP-WCMC database. AC26 Doc. 20, Annex 6, available from


  • 2011 – 2013: GIS tutorials on spatial analysis, data management and map creation, as well as intern supervision at UNEP WCMC
  • 2010 – 2011: Guided tours to Bonn Botanical Gardens on plant biodiversity and conservation for the general public, undergraduate students and school classes
  • 2009 – 2011: Undergraduate tutoring and technical assistance in GIS with BIOMAPS working group at the Nees Institute for Biodiversity of Plants, Bonn University



  • 2011: International Biogeography Society
  • 2010: International Association of Bryologists
  • 2010: British Bryological Society
  • 2009: Alexander Koenig Gesellschaft