Building on a life-long fascination with the natural world, especially the world of the sea, I naturally studied biology at the University of Groningen (choosing it for its tight links with the marine biologists at the Netherlands Institute for Sea Research). Because I was also interested in ‘deep time’, I chose to specialize in palaeontology (B5a). I was seriously interested not only in marine biomes, but also in the phenomenon of bird migration, and therefore was attracted to the WaddenSea. I became involved in shorebird counting and catching, and this lead to a series of expeditions to explore unknown intertidal ecosystems along the West African coast, connected with the WaddenSea and the Arctic by shorebird migrations. Leading my first research expedition (to Banc d’Arguin, Mauritania, in 1980) at age 21, I became hooked, and this strenuous but highly successful expedition was followed by further 2-month expeditions to Mauritania and Morocco in 1982, 1983, 1985 and 1988. The expeditions were all carried out on ‘spare’ time, but they gave me (1) the extensive field experience and perspective that has remained important to this very day, and (2) the experience to develop research plans and carry them out in teams, i.e., I gradually developed academic leadership. I tried to use my official study time at the university to become an expert on advanced topics such as whole-animal energetics in the lab and the field, organ-specific body composition analyses, and advanced ethology.
Graduating in 1984, I had made up my mind to do a PhD in what is now known as migration ecology. However, it was not until 1988 that I was given the chance to develop this idea. In the meantime I participated in expeditions, worked on limnological projects, and achieved considerable experience in the writing and publication of research papers. My PhD work on the energetic repercussions of shorebird migration became a joint venture of the two institutes that still support my work (NIOZ & RUG), and during this time I used all my previous experience to build a research team (then consisting of undergraduates) combining a variety of expertise in field and lab work. I count it as my greatest luck that soon after my PhD graduation I was given a research position at NIOZ and thereafter awarded a PIONIER grant from NWO, the first such prestigious grant awarded to an ecologist. The latter allowed me to hire the best of previous team members (as research technicians and PhD students) and together we have established a solid portfolio in intertidal and shorebird behavioural and evolutionary ecology: (1) establishing the routines to measure the intertidal resource landscapes on worldwide scales, using both optimized field surveying and satellite imaging; (2) developing, building and using an experimental, intertidal, climatized indoor arena to test field-generated hypotheses on form and function, the NIOZ Experimental Shorebird Facility; (3) achieving a solid understanding of the evolutionary trade-offs explaining predation and anti-predation behaviour at different levels in the food-web, i.e. (a) benthic invertebrate prey, (b) shorebird predators, and (c) raptorial top-predators; (4) establishing a quantitative interpretive frame-work to predict phenotype and behaviour of red knots on the basis of climatic, food-based and disease-related factors; (5) establishing the worldwide Global Flyway Network of long-term ongoing demographic studies on 20 populations of shorebirds to evaluate natural selection pressures (death and recruitment) in real time; and (6) making serious inroads in describing the genetic backgrounds of the migration phenomena, especially with respect to phylogeography and disease resistance. Over the years, the joint research team at NIOZ and RUG has become a world leader in shorebird ecology embedded in a worldwide research network, and a major player in intertidal ecology.
Major scientific achievements over the last decade
The work by my team was the first to establish the great importance of intra-individual phenotypic flexibility in ecology and evolution (and the topic of our book The Flexible Phenotype, to be published by Oxford University Press in 2011). The flexibility of individual bodies became critical to explain the distribution and behaviour of both molluscs and birds. The insights were achieved because we developed the field tools for non-invasive measurement of big organs (using ultrasound) and because we were able to experimentally test ideas from the field in our indoor intertidal facility. We have shown the importance not only of food quantity, but also of quality (especially the shell burden) to molluscivore shorebirds, and were able to establish a unique integrative picture of the inter-relationships between food, bodies, behaviour and survival. We also advanced our understanding of the dynamics of bivalve anti-predation behaviour and life-history trade-offs.
A unique feature of this knowledge-driven work in intertidal areas became the role it played in a hot societal issue, i.e. the problems of overexploitation of marine areas. The work on the demography of various shorebirds, both in marine (red knots, bar-tailed godwits) and terrestrial contexts (black-tailed godwits, ruffs), is also yielding phenomenal insights in the drivers of their distribution and abundance. Again, though motivated from science, these insights have major societal bearing. Finally, we have made spectacular progress in deciphering the recent phylogeography of several species, including the detection of population bottlenecks and genetic sweeps (the latter could be due to infectious diseases sweeping through populations).