Effects of fire frequency on species composition in a Mediterranean shrubland

Citation

Vilà-Cabrera A, Saura-Mas S & Lloret F (2008) Effects of fire frequency on species composition in a Mediterranean shrubland. Ecoscience, 15 (4), pp. 519-528. https://doi.org/10.2980/15-4-3164

Abstract
The effect of high fire frequency on the species composition of Mediterranean-type plant communities is reported on the basis of shrubland stands located in Catalonia (Spain) that have experienced from 1 to 5 fires over the last 31 years. We focused on changes in the abundance of species, grouped according to post-fire regenerative traits (resprouting and seed germination) and life form (shrubs, herbaceous graminoids, and herbaceous non-graminoids). High fire frequency was related to a low abundance of obligate resprouter and obligate seeder shrubs. In the latter group,Cistussp. disappeared in stands with high fire frequency and showed a maximum abundance in stands with low fire frequency. The abundance of facultative resprouter shrubs did not change with fire frequency. This group thus became dominant in the shrub layer at high fire frequency due to the low abundance of obligate resprouter and obligate seeder shrubs. These changes in the abundance of shrub species involve changes in the patterns of relative dominance of regenerative syndromes, in line with fire frequency. An examination of life forms revealed that the abundance of herbaceous non-graminoids and herbaceous graminoids was higher in stands with high fire frequency and the graminoidBrachypodium retusumwas dominant at all fire frequencies. These results suggest a loss in the resilience of shrubs after frequent fires, leading to a simplification of vegetation structure, with a shift from shrubland to grassland-type communities, thereby probably enhancing a potential positive herb-fire feedback.

Keywords
fire frequency; Mediterranean communities; positive herb–fire feedback; post-fire regenerative strategies; resilience

Journal
Ecoscience: Volume 15, Issue 4