PLANT REPRODUCTIVE TRAITS AS A FUNCTION OF LOCAL, REGIONAL, AND GLOBAL ABUNDANCE

Most ecological generalizations stem from the study of common organism s, but most species are rare. There are a number of reasons to expect that rare and common species may differ consistently in their characte ristics, with possible implications for conservation. Past analyses of this issue, however, have generally considered only a single measure of rarity and have not corrected analyses for the lack of independence in the traits of related species. We compared several reproductive ch aracteristics of Mediterranean annual crucifers as a function of their global range regional abundance and local population density in Israe l, making use of independent contrast methods to correct for the phylo genetic relationships of the species involved. We found plants growing at low local density to be disproportionately likely to be self-compa tible. Petal length and floral depth (sepal length) were correlated wi th breeding system but showed significant interaction effects between breeding system and abundance. Floral longevity was inversely related to abundance and also showed significant interaction effects between b reeding system and abundance. Overall, rare species tended to display more extreme values for floral traits than did common plants with the same breeding systems; they had unusually large and deep flowers ifsel f-incompatible and unusually small, shallow ones if self-compatible.