Hi all, we found, that R is not only *the* superior data analysis, graphics and statistics package, but it is also a general tool for implementing, running and teaching ecological models. Last week we held our second course "Modelling in Limnology" using R. Some material (code and docs) was produced for this purpose and may be interesting to someone else, so I put the tutorial "Konstruktion ?kologischer Modelle mit der Open Source Software R" on my homepage. The tutorial covers * a short introduction, * some simple regression models, * the modelling of populations with ODEs (thanks to Woodrow Sezter!), * some basic lake modelling stuff and * some basic individual-based techniques (population dynamics, movement, Conway's game of life, an individual-based predator-prey model). All examples are given in full source code. The tutorial is in German language, but possibly someone may be interested to work together with me on an English version in the future. It is work in progress, so please excuse typos and mistakes (some PDF errors are already known). On the other hand, I would be very glad about remarks and constructive criticism. The tutorial can be found on http://www.tu-dresden.de/fghhihb/petzoldt/zeugs.html together with an absolutely preliminary version of an accompanying library (the name simecol may be changed soon). Thank you for your feedback! Many thanks to all the people who are making the R-project possible! Thomas -- Thomas Petzoldt Tel. +49-351-463 3 4954 Dresden University of Technology Fax +49-351-463 3 7108 Institute for Hydrobiology petzoldt at rcs.urz.tu-dresden.de 01062 Dresden http://www.tu-dresden.de/fghhihb/petzoldt/