Conservation of biodiversity will necessitate choices among areas, taxa, and land-use patterns. Lack of data on distribution and pattern in biodiversity makes these difficult decisions even more problematic for those charged with the conservation and sustainable use of the diversity of life. Quantitative methods have promise in helping with this task in that they allow people to make their values explicit, and they also allow representation and comparison of many different types of data.
In this article I examine patterns of species richness and range-size rarity, or endemism, in the Neotropics with a data set from the genus Solanum (Solanaceae). Distribution data for 180 species of forest-dwelling solanums were analyzed. Patterns of species richness, range-size rarity (endemism), and several area-selection methods were examined. Montane areas are relatively rich both in all species and in endemic species, with maximal peaks in the Andes. The peak of species richness coincides with the domain (i.e., continental) midpoint (9°30′ S latitude), suggesting that the pattern observed may be partly due to the geometry of species ranges. The Solanum results are compared with those obtained for other taxonomic groups in the Neotropics, and problems with quantitative data sets in conservation are discussed. Collecting deficit, parochial taxonomy, and habitat destruction, both historical and current, are all factors that will affect the utility of such analyses. It is clear that if conservation is to work on the ground, we need to know more about what occurs in the montane Neotropics and that continued work at a basic taxonomic level is essential to our ultimate ability to conserve biological diversity.