I'm not sure exactly what you're asking: does the source of your boundary map include parameters? Since it appears that you have environmental data separate from the existing boundary map, you should be able to run a multivariate regression to determine what the most predictive variables are.

My question is more “which kind of data need ecologists for their research that take in count biotopes/habitats”. Examples: the distance between the biotope and the nearest urban area; the altitude of the biotope, etc.

Hi there. There are different parameters you could take into account. A good guideline is the work done by Marc Metzger et al. on the climatic stratification of Europe. It's published in Global Ecology and Biogeography and the map is available upon request.

http://www.formazione.unimib.it/DATA/Insegnamenti/_208/hotfolder/1/Articoli%20da%20leggere/metzger%202005.pdf

However, depending on your research focus the variables you might take into account may vary.

Yes, it's a very good paper, thank you.

Like you said, the variables to take in count vary according to research. But, I would like create a tool (the database) that can be used by many scientists for their studies. So, I must select some parameters and I would like to know which are the most important for you.

This depends again of the characteristics of the area where you are working. Basically ecological niche rules can be applied to map biotopes. We used different approaches from multivariate regression to maxent. We do have good botanical data then we used corine biotopes as a typological entry to group species. Actually we are working with associations and Alliances. Using a modelling approach like maxent you will obtain a different hierarchy of variables that are important accordingly to regional characteristics. The same tool and parameters cannot be applied to different areas if there isan important variability gradient. We are working for the whole of France on a National level initiative and after a good year of work on that problem I can assure you that you cannot use the same parameters as a black box tool without mislead crucial ecological considerations. Then fix your objectives, the characteristics of your biome and then you will find the parameters that matters.

Its quite obvious that different users will have different needs regarding habitat characterization. Two issues seem noteworthy:

One should be aware of the difficulties in classifying a habitat from remote sensing data, even with the use of good ancillary data - field work is most recommended. From an ecologic point of view its critical to have a clear notion of the bioclimatic and biogeographic context of each habitat (hence the need for good ancillary data), together with a set of diagnostic species that will assist you to make a correct diagnostic on the field regarding the presence/absence of a certain habitat. Having said that, its also evident that this is a valid approach for most habitats (meaning NATURA 2000 habitats), but not all of them: Cavities (habitat 8310) have no diagnostic species and are mostly dependent on geological/geomorphological context and habitats like Estuaries (habitat 1130) are composed of a complex mosaic of plant communities, many of them included in other NATURA 2000 habitats.

Finally, from the manager point of view some patch metrics may be of high interest, especially if trends over time can be studied using these metrics. This may require retrospective studies but because of the reasons I mentioned earlier, many limitations may occur in this process. Also a good diagnostic of the (potential) threats and disturbance sources (some of which may be useful to the habitats persistence) may be of high interest.

In the Portuguese case some of this information was put together in what was called: 'NATURA 2000 characterization and management files', that can be found here (http://www.icn.pt/psrn2000/caract_habitat.htm ) but because these are in Portuguese, a synthesis of this may be found here (https://www.researchgate.net/publication/231521517_The_application_of_the_Habitats_Directive_in_Portugal). Hope you find it useful.

Article The application of the Habitats Directive in Portugal

It is as has been said by others depending from your objectives. In general, however, what we did in the EBONE project and in the publications from it, the natural characteristics are climatic (T, P, E), soil characteristics, the vegetation cover or water cover (be aware that aquatic/wetlands behave differently from non flooded habitats. If you want to characterise habitats at the European/global level, indeed follow Metzger et al 2013. You will find an overview of the approaches we have chosen in the journal Ecological Indicators Issue 33, a special issue on biodiversity monitoring. Detailed reports, also on characterisation of habitats you can find through the Alterra website (free downloadable reports) and I have put most here on RG as well.