To live or not to live? Assessing the role of cacti growth forms on survival and resprouting after a wildfire

Abstract Cactaceae is an important plant family in the semi-arid ecosystems of the Americas. However, few studies have analyzed their responses after wildfires. In this study, we assessed the survival rate and resprouting capacity of cacti from different growth forms one year after a wildfire in the Córdoba Mountains, central Argentina. Eight species are present in the study area, which were classified into four growth forms; then we established 158 plots and recorded the status (dead or alive) of each cactus and size-related variables. We also documented microenvironmental characteristics (percentage cover of grasses, forbs, shrubs, rock and bare ground) and topographic information (slope and slope orientation) for each plot, estimating the resprouting capacity of each growth form. Survival rates and resprouting capacity varied among growth forms. The survival rate for arborescent growth form was 25%, while for globose, opuntioid and short columnar forms were 84%, 69% and 55%, respectively. Microenvironmental and topographic factors influenced resprouting capacity, though effects varied among growth forms. Globose growth form showed the highest recovery capacity after the wildfire, contrasting with arborescent growth form, of which only 2% of the individuals resprouted, predominantly on south- and north-facing slopes. In contrast, short columnar and opuntioid growth forms showed no significant relationship between survival or resprouting capacity, and the measured variables. These findings provide key insights into the role of fire in shaping cacti populations and highlight the need to consider species-specific and environmental interactions in conservation and management strategies for the Chaco forest.