We. Kunin et A. Shmida, PLANT REPRODUCTIVE TRAITS AS A FUNCTION OF LOCAL, REGIONAL, AND GLOBAL ABUNDANCE, Conservation biology, 11(1), 1997, pp. 183-192
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.