title: The chaparral vegetation in Mexico undernonmediterranean climate: the convergence and Madrean-Tethyan hypothesesreconsidered.
abstract: A comparative study between an unburned evergreen sclerophyllousvegetation located in south-central Mexico under a wet-summer climate,with mediterranean regions was conducted in order to re-analyzevegetation and plant characters claimed to converge under mediterraneanclimates. The comparison considered floristic composition,plant-community structure, and plant characters as adaptations tomediterranean climates and analyzed them by means of a correspondenceanalysis, considering a tropical spiny shrubland as the external group.We made a species register of the number of species that resproutedafter a fire occurred in 1995 and a distribution map of the evergreensclerophyllous vegetation in Mexico (mexical) under nonmediterraneanclimates.The Tehuacán mexical does not differ from the evergreensclerophyllous areas of Chile, California, Australia, and theMediterranean Basin, according to a correspondence analysis, whichordinated the Tehuacán mexical closer to the mediterranean areasthan to the external group.All the vegetation and floristic characteristics of the mexical, aswell as its distribution along the rain-shadowed mountain parts ofMexico, support its origin in the Madrean-Tethyan hypothesis of Axelrod.Therefore, these results allow to expand the convergence paradigm of thechaparral under an integrative view, in which a general trend to ariditymight explain floristic and adaptive patterns detected in theseenvironments.
authors.affiliation: Instituto de Ecología, Universidad NacionalAutónoma de México, Apartado Postal 70-275, UNAM,04510 México, D.F.; and.
authors.forename: A
authors.initials: A
authors.lastname: Valiente-Banuet
authors.forename: N
authors.initials: N
authors.lastname: Flores-Hernández
authors.forename: M
authors.initials: M
authors.lastname: Verdú
authors.forename: P
authors.initials: P
authors.lastname: Dávila