Differences in species composition between sites were quantified by the Jaccard similarity index; that is, by the proportion of shared species from the combined total of species found at the two compared sites (Koleff et al., 2003a). The correlation between Jaccard similarity and geographic distance was tasted with the Mantel test using all possible pairs of study sites.The completeness of each survey was assessed by constructing species accumulation curves that show the rate of new species discovery during the survey. The rate of increase in total species richness with increasing number of surveyed sites in each of the three regions was assessed from species accumulation curves that combined sites in random order. All possible subsets of sites from the total of 5-6 sites studied in each area were use to estimate the mean, minimum and maximum species richness for each particulars number of sites. The total number of species expected in each studied area was estimated using the Chao 2 index, suitable for the analysis of species lists from multiple sites (Colwell & Coddington, 1994 ).The geographic distribution of each species was characterized by the number of sites as which it was recorded and by the maximum geographic distance between the occupied sites. Pair-wise distance between our studied sites ranged from 80 to 503 (median 290) km for New Guinea, from 20 to 400 (170) km for Amazonia, and from 20 to 330 (220) km for Europe. We therefore used the distance of 250 km, close to the median distance between sites in our three studied areas, to separate species with restricted and widespread distribution. The widespread species were defined as those found at sites >250 km apart, restricted species as those at multiple sites <250 km apart, and local species as those at a single site. The geographic distribution analyzed here is not a substitute for the size of the species’ geographic range, but is a different characteristic of distribution, measuring the frequency of occurrence within the species’ geographic range.
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