Survival and growth of cactus species after a wildfire in central Argentina: Differences among species and the effects of microenvironment characteristics

Abstract

There are about 2200 cactus species, and most of them occur in fire‐prone ecosystems. Nevertheless, there is scarce information about fire effects on the ecology of cactus species. In this study, we assessed the effects of a wildfire on the survival and growth of coexisting globose cactus species and their relation with microenvironment conditions in rocky outcrops from the Córdoba Mountains, central Argentina. A fire event occurred in spring 2011, and measurements were recorded in the first subsequent growing season, in winter. We selected 26 rocky outcrops and established three 3 × 1 m plots per outcrop. In each plot, we quantified all cactus individuals of the four species present in the area: Echinopsis aurea, Gymnocalycium bruchii, G. mostii and Parodia submammulosa. We also recorded if each individual cactus was dead or alive, and measured its size and post‐fire growth. In addition, we measured the relative cover of rocks and bare soil, and the size of the rocks within a radius of 30 cm of each individual. Individual cactus survival (70–80%) did not vary among species. The highest post‐fire growth was recorded in G. bruchii. For E. aurea, P. submammulosa and G. mostii, post‐fire growth was negatively related to pre‐fire size, suggesting that smaller individuals recovered faster than larger ones. Microenvironment characteristics did not affect post‐fire growth in any of the species. Our results provide a preliminary insight into possible fire tolerance of globose cacti in the Córdoba Mountains, supported by their relatively high survival and growth after a fire event.

Growing or reproducing? Assessing the existence of a trade‐off in the globose cactus Gymnocalycium monvillei

“…We calculated growth (expressed as percentage) as the difference between those measurements (Zupichiatti et al . 2022). In addition, in each individual, we counted all the fruits produced during two growth seasons, 2018–2019 and 2019–2020, measured their height and width, and collected one to two fruits per plant.…”

“…We determined the size of each individual plant by measuring the diameter with a calliper at the beginning and end of the growing season, in September 2018 and April 2019, respectively. We calculated growth (expressed as percentage) as the difference between those measurements (Zupichiatti et al 2022). In addition, in each Fig.…”