|Have a look at Biomapper at work!|
|This page describe step by step how to conduct a complete
analysis, beginning with environmental data and ending with a validated
Habitat Suitability map.
A. PreliminariesYou begin by converting the data you have collected (field sampling, official databases, etc.) into Idrisi-formatted maps. These operations can be done with Idrisi or Biomapper, or any other tool you want (I frequently use Corel Draw, MapInfo, ASCII editors as well as home made programs).
When you have got maps that are usable by Biomapper and Idrisi, you can work with them. There are two kind of operations you will want to do:
C. AnalysesYou are now ready to perform the Ecological Niche Factor Analysis. This will give you many output (scores matrix, etc.) that you should examine attentively in order to verify them and to get ecological understanding about the focal species. Now, you have got your Habitat Suitability model.
D. Map productionFinally, you can use this HS model to compute a HS map. This map should then be validated with independent data (prepared during the step B).
|This analysis is the central part of Biomapper. It is designed
to compute the factors (like the Principal Components Analysis) that explain
the major part of the ecological distribution of the species. Like in the
PCA, the extracted factors are totally (by construction) uncorrelated but
in this case they have biological signification: the first factor is the
factor, which describes how far the species optimum is from
the mean habitat in the study area. The specialisation
factors are sorted by decreasing amount of explained variance;
they describe how specialised the species is by reference to the available
range of habitat in the study area. Therefore, only a few of the first
factors explain the major part of the whole information.
[More details on ENFA]
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