Canoco
Canoco ( canonical correspondence analysis ) is a computer program for ecological vegetation analysis developed by Cajo JF ter Braack in the 1980s .
Canoco is a further development of DECORANA. The specialty of Canoco lies in the fact that the composition of species recordings, e.g. B. from vegetation recordings , to be attributed to variations of known environmental variables. The usual correspondence analysis uses the method of recoprocal averaging to extract latent dimensions from data records on the occurrence or frequency of species, according to which the species can be arranged. These dimensions are usually examined in a second step after their correlation with environmental variables (“indirect” gradient analysis ).
In contrast to the two-step indirect gradient analysis, Canoco performs a direct gradient analysis in one calculation step. For this purpose, an additional restriction is inserted into the correspondence analysis: The latent dimensions may only be formed as a linear combination of the environmental variables. Consequently, the geometric arrangement of the species can be interpreted directly in relation to the environmental gradients. As many dimensions can be extracted as there are environmental variables. For data sets in which the species distribution follows a normal distribution in the form of a “bell curve”, special “detrending” procedures are available.
The Windows version of Canoco was developed together with Petr Šmilauer .
Web links
- Official Canoco website of the plant research international group at Wageningen University
Individual evidence
- ^ Cajo JF ter Braack (1989): CANOCO - an extension of DECORANA to analyze species-environment relationships . Hydrobiologia 184: 169-170
- ^ A b Cajo JF ter Braack (1985): Canonical Correspondence Analysis: A new Eigenvector Technique for Multivariate Direct Gradient Analysis . Ecology 67 (5): 1167-1179