Fire and resprouting in Mediterranean ecosystems: Insights from an external biogeographical region, the mexical shrubland

We investigated modes of regeneration of dominant species of the mexical ve getation after fire. The mexical shrubland shows a remarkable structural, m orphological, and Aoristic similarity to Mediterranean-type vegetation and is considered a relict of the Madro-Tertiary Geoflora under a non-Mediterra nean climate. This vegetation provides an ideal scenario to test the role o f fire in Mediterranean ecosystems because historical fire occurrence is ab sent and the species assembly is constituted mostly by Madro-Tertiary eleme nts and Neotropical species (some of them, endemic species from Mexico). Th e existence of congeneric species of the California chaparral allows us to determine the regeneration ability of these communities after fire in relat ion to resprouting and seeding strategies, which are widespread modes repor ted in the Mediterranean-type vegetation. By the experimental application o f fire in the two biogeographical groups of species, we tested the hypothes is that low resprouting ability of California congeneric species (Madro-Ter tiary species) after fire would indicate that fire has played an important selective force in the resprouting habit. A low resprouting ability in the Neotropical group of species would suggest that fire has molded the set of species dominating fire-prone environments. Our results indicated that resprouting is a widespread trait in the mexical species characterized by the presence of lignotubers and burls. Resproutin g can be considered an ancient trait, probably linked to losses of abovegro und biomass, that became a pre-adaptation in;Mediterranean fire-prone commu nities. The Neotropical group of species showed less ability to regenerate after fire. and small plants were more likely to die after disturbance in t his group than in the Madro-Tertiary group. The resprouting feature and the seeder strategy of other species after a fire in the mexical shrubland are similar to Mediterranean-type ecosystems, emphasizing their common origin and the relevance of phylogenetic and biogeographical studies to explain cu rrent patterns of vegetation.