In fire-influenced ecosystems, some plant species have the ability to recover, germinate, and to establish after a fire; however, their proportion and dominance varies between sites. The objective of this work was to evaluate natural regeneration following a fire in a tropical dry forest located in the Upper Magdalena River Valley in Colombia. In that way, all seedlings and saplings of woody species were recorded, 1.5 years after a fire, in 75 2x2-m plots installed in burned and unburned forest sites, as well as in forest gaps. Results showed that although abundance was higher in the burned sites, the species richness was lower than in unburned areas. Based on the regeneration response of the species, we identified three groups of plants: 1) fire-stimulated, 2) fire-tolerant, and 3) fire-sensitive species, which means that this tropical dry forest has species with the ability to recover, germinate, and establish after a fire. These three groups of plant species should be considered in restoration programs in light of future and more frequent forest fires due to climate change.
TopIntroduction
Fire has been considered an important disturbance agent that influences composition and structure of plant communities in several ecosystems of the world (Rodrigues, Martins, & Matthes, 2005; Alanís-Rodríguez et al., 2012; Oliveira et al., 2014; Salazar & Goldstein, 2014; Bhadouria et al., 2017; Young et al., 2018; Koontz, North, Werner, Fick, & Latimer, 2019). In fire-influenced ecosystems some plant species have the ability to resprout, germinate and establish after fire (Hoffmann, 2000; J. E. Keeley & Fotheringham, 2000; Rodrigues et al., 2005; Pausas et al., 2016; Ocampo-Zuleta & Bravo, 2019). Thus, depending on the proportion of these species in comparison to others that do not have such adaptations, some ecosystems will have a greater or lesser capacity to recover from the occurrence of forest fires (Pausas & Lavorel, 2003; Pausas, Bradstock, Keith, Keeley, & Network, 2004; Hardesty, Myers, & Fulks, 2005; Myers, 2006; Pausas et al., 2016). Moreover, based on the plant’s capacity to regenerate after being exposed to fire or heat, different studies have all proposed three categories of germination and regeneration: fire/heat-tolerant, stimulated and sensitive (Otterstrom, Schwartz, & Velazquez-Rocha, 2006; Griscom & Ashton, 2011; Jaureguiberry & Díaz, 2015). These classifications have also been used for seedlings and saplings found in the understory after a fire (Rocca, 2009).
Mechanisms of post-fire plant regeneration have been widely studied in Mediterranean ecosystems, temperate zones and tropical savannas (Pausas et al., 2004; Hardesty et al., 2005; Rodrigo, Retana, & Xavier, 2005; Shlisky, A. et al., 2007; Gómez-González et al., 2017). In contrast, in tropical dry forests, information is more limited (Snook, 1993; Kellman & Meave, 1997; Myers, 2006; Bhadouria et al., 2017), and most of the studies have been carried out in the Brazilian Cerrado, Mexico and Bolivia (e.g. Fredericksen & Mostacedo, 2000, Rodrigues et al., 2005, Alanís-Rodríguez et al., 2010, Carón, Dalmasso, Ortín, & Verheyen, 2015, Gómez-González et al., 2017). Additionally, several studies have focused on invasive species while very little is known about the native ones (Gómez-González et al., 2017, Hoffmann, 2000, Lahoreau et al., 2006).