Dear Mohammed,
There are several ways you can use to decide which variables to use. First, you only want to include variables that are connected to the species ecology. For example, for birds, there are a number of bioclimatic variables that are known to influence their distribution, and these variables are often used in species distribution modeling (e.g. Barbet-Massin, M., Thuiller, W., Jiguet, F., How much do we overestimate future local extinction rates when restricting the range of occurrence data in climate suitability models? Ecography 33, 878-886.). Second, you can examine the correlations between the variables you want to use and choose a set of variables that are not too strongly correlated. Thirdly, you can use a larger number of variables and let ENFA decide which ones to use. ENFA will convert your variables to a number of factors, and the BIOMAPPER program has a built-in function that allows you to decide how many factors to keep.
All the best,
Diederik
On 10/8/2011 9:59 AM, mohammad wrote:
Dear friends
I'm working on "distribution patterns of astragalus in old world". I'm using worldclim database for ecological nich modeling by Diva-Gis software. I will be appreciating if you answer my question:
How I can find most important and most effective bioclimatic factors on distribution of specie in my project?
Best regards,
-- Dr.Diederik Strubbe Evolutionary Ecology Group Department of Biology University of Antwerp Middelheimcampus GV310 Groenenborgerlaan 171 2020 Antwerpen, Belgium office: +32 3 265 3282 mobile phone: +32 477445568 skype user name: lakrinn
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