Flammability of plant communities in arid and semi-arid ecosystems: Identifying key drivers and management implications

Arid and semi-arid ecosystems are prone to extensive fires due to specific climatic conditions, sparse vegetation cover, and high density of fine fuels. Understanding the flammability characteristics of land covers is essential for fire management and designing land restoration programs in arid and semi-arid ecosystems. This study provided a new approach to evaluate the flammability of shrublands and woodlands using flammability indices (FIs) including time to ignition (TI), duration of combustion (DC), and flame height (FH) of plant species and their relative frequencies in the Dalfard Basin of southeastern Iran. The results showed that there was a significant difference in FIs between land covers. Shrublands had higher flammability potential compared with woodlands. Plant moisture content had a negative relationship with TI ( P <0.010) and no significant relationship with DC and FH ( P >0.050). Artemisia spp . , Astragalus gossypinus Fischer, Amygdalus scoparia Spach, and Cymbopogon jwarancusa (Jones) Schult. had the highest FI. Tree species such as Rhazya stricta Decne., and Pistacia atlantica Desf. showed greater resistance to fire. Using principal component analysis, the relationship between species and FIs was examined, and TI of wet fuel was the most important FI in relation to species. Structural equation model showed that life form ( P <0.001) was the most important flammability driver. Precipitation ( P <0.010) and legume species ( P <0.010) were significantly related to the flammability in arid land. This study emphasizes the importance of managing high-risk species and using resistant species in vegetation restoration and shows that combining species FIs with their abundance is an effective tool for assessing fire risk and fuel management at the plant community scale.