New: R functions for vegetation ecologists: Featuring Decorana, [partial] [constrained] correspondence analysis and support functions for NMDS.
Homepage of Jari Oksanen University of Oulu
Department of Biology
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Welcome to my homepage. You can find here discussion about plant ecology and vegetation science.
Instability of ordination Tausch et al. (Journal of Vegetation Science 6, 897-902; 1995) found out that some programs for Correspondence Analysis and other vegetation data analyses gave different results when the input order of species or sites changes. Peter Minchin and me found that CANOCO is subject to the same instability (Journal of Vegetation Science 8, 447-454; 1997). Here we give some information and software to analyse and cure the instability.
Diversity hump Discussion on humped-back species richness model which started with my Forum article in Journal of Ecology 84, 293-295 (1996). Here I explain briefly my point of view.
Beta and HOF models Discussion on fitting beta response function in gradient model. This is related to my paper where I criticize the use of beta-function in gradient analysis. I provide here software to simulate vegetation data. My argument is that fitted beta functions do not recover the true model used in simulation, but give biased results in general. My recommendation is to use Huisman-Olff-Fresco models instead to estimate skewness of species responses.
Software Some ecological software, though it comes with usual no-warranty: I don't guarantee that it works or that it can be used for any purpose.
Ordination stability -- HOF model -- Beta response simulation -- Diversity hump fit -- Icons