We can thus re-interpret the higher robustness found for Amazonia: it suggests a high proportion of more uniformly distributed species with medium and larger numbers of species occurrences, and a low proportion of small-clustered species and species with few occurrences. The LOOCV approach does not account for errors due
to heterogeneous data quality or sampling effort. Whereas we integrated a strategy to adjust for heterogeneous spatial sampling effort at the level of species richness, we did not include an adjustment for the fact that more selleck screening library recent monographs will be more complete in terms of both taxa and occurrences considered. For the future, the interpolation process could be altered to include an additional weighting at species level. Furthermore, our maps will improve if more data based on future monographs were to be included in the analysis. The results identified here are not absolute estimates of species richness per quadrat. To obtain a rough estimate of the absolute figures, the numbers per quadrat found need to be multiplied by the factor 20, since our data set represents approximately
about 5% of the angiosperm flora PXD101 cost occurring in the Neotropics. Following this estimation, our uppermost results would lie in close proximity to the uppermost results of Barthlott et al. (2005) suggesting more than 5,000 vascular plant species in the most species-rich 10,000 km2 units, and find more that of Kreft and Jetz (2007), modeling 6,500 species at maximum per most species-rich 1° quadrats. Methane monooxygenase Although our species richness map can only approximate ‘real patterns’, this consistency broadly supports our
estimation of distribution patterns. Narrow endemic species Compared with previous work (Morawetz and Raedig 2007), in spite of considering more species, a similar number of species is identified as narrow endemic species. Previously, all species occurring in three or fewer quadrats were defined as narrow endemic species irrespective of distance between species occurrences, while in the present work only those species that occurred in five or less quadrats after interpolation with the maximum distance of five quadrats qualified as narrow endemic. Although the threshold of five quadrats appears more generous, the method is more rigorous in that it considers spatial distance. The main differences seen between Morawetz and Raedig (2007) and the present study are the absences of some species in southeastern Amazonia and in the Cerrado and Caatinga (two Brazilian floristic provinces) whose recorded occurrences were too geographically distant to be considered narrow endemic. The analysis of narrow endemic species revealed two shortcomings of our interpolation method: first, if quadrats hold no species after interpolation, no adjustment of sampling effort can be applied. Considering the large number of empty quadrats, the map of narrow endemism (Fig. 6a) might reflect sampling effort more than distribution patterns.