Dr. Henk van der Hammen
In memoriam Henk van der Hammen (4 August 1943 - 20 August 2002): Henk van der Hammen was born just north of Amsterdam in the small town of Landsmeer. He was educated to become a schoolmaster. However, after his military service, he worked at a scientific antiquariat.Then in 1970 he studied biology at the University of Amsterdam,. After completing his studies in 1977, he made an inventory of macro-invertebrates of Waterland, an area north of Amsterdam. In 1979 he went to work for the province of North-Holland, with the aim of making an inventory of this area’s macro-invertebrates. During his work for the province, water mites became his favourite invertebrates He used the material and data of the North Holland inventory in his thesis "The macro-invertebrates of North-Holland", to complete his graduate work at the Catholic University of Nijmegen in 1992. Together with Harry Smit he collected water mites throughout The Netherlands, resulting in many species that were new for the fauna of The Netherlands and even describing a species that was new to science. The results of these collections were published in the "Atlas of Dutch water mites" in 2000. Another landmark was the publication of water mites of streams from The Netherlands, which showed the enormous detoration of this habitat. In a pond near his home, he started a project which involved the monthly collection of water mites. He observed the changing of water mite composition with the succession of the pond's macrophytes. Unfortunately, he didn't find the time to publish the results of this project. He started the project quite some years ago and the amount of information is enormous. Finally, together with five other acarologists, he worked on a new reference work on the water mites of Central, Western and Northern Europe. A tragic traffic accident caused the loss of his live. We loose in him a friend and a dedicated acarologist.

Smit, H. & H. van der Hammen (1990): Taxonomic notes on some Arrenurus species (Acari: Hydrachnellae). - Entomologische Berichten, Amsterdam 50: 52-55.
Hammen van der, H. (1992): De macrofauna van Noord-Holland. - Thesis KU Nijmegen. Provincie Noord-Holland, Haarlem, 256 pp. (in Dutch)
Smit, H. & H. van der Hammen (1992): Water mites as indicators of natural aquatic ecosystems of the coastal dunes of The Netherlands and northwestern France. - Hydrobiologia 231: 51-64.
Smit, H. & H. van der Hammen (1992): A new species of Albia (Albiella) from The Netherlands (Acari: Hydrachnellae). - Entomologische Berichten, Amsterdam 52: 114-116.
Smit, H. & H. van der Hammen (1992): New and rare water mites from The Netherlands (Acari: Hydrachnellae). - Entomologische Berichten, Amsterdam 52: 144-146.
Smit, H., H. van der Hammen & G. Duursema (1993): New species of water mites for the Dutch fauna, with some taxonomic notes on the genus Nautarachna (Acari: Hydrachnellae). - Entomologische Berichten, Amsterdam 53: 180-182.
Hammen van der, H. & H. Smit (1996): The water mites (Acari: Hydrachnidia) of streams in The Netherlands: distribution and ecological aspects on a regional scale. - Netherlands Journal of Aquatic Ecology 30: 175-185.
Smit, H. & H. van der Hammen (1996): Nieuwe watermijten voor de Nederlandse fauna (Acari: Hydrachnellae) - Entomologische Berichten, Amsterdam 50: 93-96.
Smit, H. & H. van der Hammen (1996): A remarkable assemblage of water mites in quagfens and carr in The Netherlands (Acari: Hydrachnellae). - Entomologische Berichten, Amsterdam 56: 28-32.
Smit, H. & H. van der Hammen (2000): Atlas van de Nederlandse watermijten. - Nederlandse Faunistische Mededelingen 13: 1-272.