VILLASEÑOR, JOSÉ L. Departamento de Botánica. Instituto de Biología, U.N.A.M. Apartado Postal 70-367. 04510 México, D. F. - Patterns of geographical distribution of Mexican Senecioneae (Asteraceae).
The Senecioneae in Mexico are represented by 22 genera and about 242
species. Along with Central America, Mexico is considered an important
concentration site of species of the tribe. At least 7 genera and 69%
of the species are endemic or nearly endemic. Ten genera and 28
species are shared with North America whereas 12 genera and 38 species
also occur in Central America. Based on the study of the specimens
housed at the National Herbarium of Mexico (Mexico City), analyses of
the distributional patterns of Mexican Senecioneae are carried out.
Results indicate that members of the tribe concentrate along the
Transvolcanic Belt and southern Mexico. The aim of this work is to
identify the regions with high concentrations of species (hot spots).
Special emphasis is put on the endemic element. The latitudinal
distribution of species is discussed, and by using multivariate
techniques, new regions for Senecioneae distribution are defined using
Guatemala, the Mexican states, and the U. S. states along the Mexican
border (Arizona, California, New Mexico, and Texas). With these
analyses, the important biogeographical areas for the tribe in Mexico
are defined, and its relevance for conservation is discussed.
Key words: Asteraceae, Biogeography, Conservation, Endemism, Mexico, Senecioneae