Ecologist Jan van Gils investigates the red knot, a wader that breeds in the Arctic, overwinters in the Wadden Sea, but also migrates through the Netherlands to its winter quarters in West Africa. ‘In effect, the red knot is like a canary in a global coal mine. Just like the miner’s canaries in the past warned for impending high concentrations of mine gases, the red knot now informs us now about the state of the climate.’
‘We can see that over the past 35 years, red knots have gradually become smaller, and we are now investigating whether that might be due to insects in the rapidly warming Siberian breeding grounds emerging from the soil earlier; too early for red knot chicks to grow to full adult body size. In the overwintering area in West Africa, it is precisely the smaller red knots that tend to perish first, because their beaks have become too short to reach the food. The birds with the highest chance of survival are those that still have a relatively long beak despite the shrinking. So here we see evolution in action: red knots are becoming smaller with relatively longer beaks.’
‘Red knots are not only shrinking; a shift in their sex ratio is occurring too. Male birds are increasingly often in the minority, and that is already the case when they hatch from the egg. That also seems to be a consequence of the shifting temperature and the lower survival chances of the males, which are slightly smaller than the females.'
'All things being considered, we study far more than just the one species of wader, however interesting that one species is. The red knot connects the far north with our Wadden Sea, with Africa, and ultimately with our entire planet. What we do with greenhouse gases in the atmosphere has a relatively strong effect on the Arctic region and with that eventually on the survival of birds in West Africa. The fact that the red knot is shrinking is a foreboding sign. Research into fossils reveals that animals that became extinct often experienced a period of shrinking first.’Read more +
In the current biodiversity decline, predators are often the first to disappear. Predators are thought to play a positive role in biodiversity maintenance as they prevent certain prey species in achieving dominance, relaxing resource competition among prey, hence promoting prey growth rates, prey coexistence and diversity. Losses of species at the highest trophic levels in communities may therefore cause extinctions and shifts in size structure at lower trophic levels. However, this role of predators is still often underappreciated, largely because many ecosystems have already lost their top-predators and/or human-induced disturbances now blur the positive predation effects. Most of all, the role of migrant predators structuring communities along their migratory route has mostly been neglected.
Aiming to fill this knowledge gap, we study the role of molluscivore shorebirds for intertidal benthic communities, with a focus on the pristine and uninhabited Banc d’Arguin (Mauritania). On their way to and from Mauritania, these shorebirds (re)fuel in the Dutch Wadden Sea, an area that has lost much of its value due to human disturbance (notably bottom-disturbing fisheries). Therefore, molluscivore shorebird numbers are on the decline, both in the Wadden Sea and in West-Africa, and we are investigating whether the benthic community changes observed at Banc d’Arguin may in fact represent ‘spatial knock-on effects’ of human disturbance in the Wadden Sea. Recently, in parallel with the project in Mauritania, a project on crustacean-eating crab plovers in Barr al Hikman (Oman) has started.
From 2020: Honorary Professor, Global Change Ecology of Migrant Shorebirds, University of Groningen
2015-2019: Lecturer, MSc programme Marine Biology, University of Groningen (ad honorem)
From 2014: Senior Scientist at NIOZ
2010-2014: Tenure Tracker at NIOZ (NWO-VIDI grant)
2006-2010: Postdoc at NIOZ (NWO-WOTRO grant)
2006-2007: Postdoc at Bristol University, UK (NWO-TALENT grant)
2003-2008: Postdoc at NIOO (KNAW-Vernieuwingsfonds)
1997-2004: PhD-student at NIOZ/University of Groningen (NWO-PIONIER grant)
Rakhiemberdiev, E., Duijns, S., Karagicheva, J., Camphuysen, C. J., VRS Castricum, Dekinga, A., Dekker, R., Gavrilov, A., ten Horn, J., Jukema, J., Saveliev, A., Soloviev, M., Tibbitts, T.L., van Gils, J.A. & T. Piersma (2018). Fuelling conditions at staging sites can mitigate Arctic warming effects in a migratory bird. Nature Commun. 9, 4263.
van Gils, J.A., Lisovski, S., Lok, T., Meissner, W., Ożarowska, A., de Fouw, J., Rakhimberdiev, E., Soloviev, M.Y., Piersma, T. & M. Klaassen (2016). Body shrinkage due to Arctic warming reduces red knot fitness in tropical wintering range. Science 352, 819-821.
van Gils, J.A., van der Geest, M., Leyrer, J., Oudman, T., Lok, T., Onrust, J., de Fouw, J., van der Heide, T., van den Hout, P.J., Spaans, B., Dekinga, A., Brugge, M. & T. Piersma (2013). Toxin constraint explains diet choice, survival and population dynamics in a molluscivore shorebird. Proc. R. Soc. B 280, 20130861.
van der Heide, T., Govers, L.L., de Fouw, J., Olff, H., van der Geest, M., van Katwijk, M.M., Piersma, T., van de Koppel, J., Silliman, B.R., Smolders, A.J.P. & J.A. van Gils (2012). A three-stage symbiosis forms the foundation of seagrass ecosystems. Science 336, 1432-1434.
Piersma, T. & J.A. van Gils (2011). The Flexible Phenotype: A Body-Centred Integration of Ecology, Physiology, and Behaviour. Oxford University Press, Oxford. 238 p.
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Find my PhD thesis here.
2004: PhD Mathematics and Natural Sciences, University of Groningen (cum laude)
1996: MSc Biology, University of Groningen (cum laude)
1990: BSc Biology, University of Groningen (cum laude)
1989: Athenaeum B, Theresialyceum, Tilburg
2019: Vici Grant, NWO (1,5 M€)
2015: MARES Grant (Erasmus Mundus, EU)
2013: Research Project Grant, TRC (Oman)
2009: Vidi Grant, NWO
2007: Dutch Zoology Prize, Royal Dutch Zoological Society
2006: WOTRO Integrated Programme, NWO
2005: Rubicon Grant, NWO
2004: Best PhD Thesis in Functional Ecology Graduate School
Remote sensing and geospatial data analysis of Barr al Hikman intertidal ecosystem (TRC grant, Oman)
Fragile biodiversity linkages: production and consumption in a nutrient-poor seagrass-dominated intertidal ecosystem, the Banc d’Arguin, Mauritania (NWO-WOTRO grant)