Over more than a century a widespread process of land use change has taken place worldwide, by which native ecosystems, mainly forests, have been replaced by agricultural fields (Lambin & Meyfroidt, 2011; Runyan & D’Ordorico, 2016). In tropical regions, where swidden agriculture is often practiced, agricultural fields are usually abandoned after a few years of use due to a reduction in their productivity and yield (Aide et al, 2000). After land abandonment, a process of secondary succession starts, leading to vegetation cover recovery (Chazdon, 2014; Letcher et al., 2015). If undisturbed, the community is capable of reaching a relatively stable state (Poorter et al. 2021; Muñoz et al. 2021). Globally, around half of all tropical forests are secondary communities which are recovering from previous disturbances (FAO, 2015), and this figure continues to increase as many native forests are being cleared, replaced and abandoned as the agricultural frontier continues to expand (Meyfroidt & Lambin, 2011).

A common pattern consisting of three stages has been recognized in tropical forest secondary succession (Finegan, 1996; Lebrija-Trejos et al., 2011; Mora et al., Trilleras, 2015; Rozendaal et al., 2016; Martínez-Ramos et al., 2021; Rüger et al., 2023). The first stage is characterized by the dominance of weeds, shrubs, and climbing plants. Next, the establishment of fast-growth, short- and long-lived trees characterizes a second stage, which eventually gives way to a third stage characterized by the establishment and development of the seedlings of slow-growing long-lived tree species under the canopy of the fast-growing trees. Those species that establish in early succession (pioneers) can either display a fast demographic strategy (grow, reproduce and die quickly) or have a longer lifespan (long-lived pioneers), while mature forest species, with a slow demographic strategy, establish later in succession (Rüger et al., 2023). The differential presence and abundance of species in each of the three stages is determined by the prevailing environmental conditions at each successional stage, which in turn are driven by a feedback dynamics between the environment and the community (Wallace & Romney, 1980; Lebrija-Trejos et al. 2011; Letcher et al., 2015; Matsuo et al. 2021). Therefore, the presence of certain pioneer species may facilitate or hinder the performance of other species depending on how they modify the environment. Ultimately, dominant pioneers play a substantial role in a community’s successional dynamics and ecosystem functioning (Grime 1998).

Several studies have focused on secondary succession in tropical dry forests (Kennard, 2002; Peña-Claros, 2003; Lebrija-Trejos et al., 2010a; Lebrija-Trejos et al. 2010b; Dupuy et al., 2012; Pineda-García, Paz & Meinzer, 2013; Mora et al., 2015; Rozendaal et al., 2016). In these systems, the most important limiting factor is water availability (Murphy & Lugo, 1986; Allen et al. 2017), which entails low plant growth rates (Rozendaal et al., 2016), and also explains why succession in these forests is often dominated by very few drought-tolerant species (Ceccon et al., 2006; Markesteijn, Poorter, Paz, Sack & Bongers, 2011; Rozendaal et al., 2016). In particular, in the tropical dry forest of the Nizanda region, southern Mexico, Lebrija-Trejos, Bongers, Pérez-García, and Meave (2008) found a three year-long initial successional phase characterized by shrub growth. After this stage, early successional Mimosa acantholoba var. eurycarpa trees become dominant over a few decades, creating a canopy layer that provides shade and reduces the air temperature in the forest understory, apparently allowing mature forest species to establish and eventually dominate late-successional stages.

Previous studies established M. acantholoba var.eurycarpa ’s dominance, based on its high basal area and density of individuals compared to other species of the tropical dry forest of Nizanda (Romero, 2014). However, little is known about the traits that underlie its dominance; although initially its thin leaves and high leaf dry mass content were proposed (Romero, 2014), a recent study showed that wood anatomical traits in this species ensure efficient water conduction in the rainy season while reducing its hydraulic vulnerability in the dry season (Romero et al., 2020). Nevertheless, it is likely that some other aspect of its life cycle, such as its population dynamics, may be also involved in this pattern.

An important demographic process of pioneer species population dynamics in early succession is the entry of new individuals to the population. We name these new individuals recruits when they derive from seed germination and seedling establishment. Alternatively, there are individuals entering the population through the resprouting of vegetative structures (stumps or roots) that remain alive in the sites after the agricultural use of the field; we name these resprouts. The absence of reproductive individuals in early succession implies that its population dynamics necessarily depend on processes other than reproduction from mature local trees. These processes encompass seed dispersal from the surrounding forest matrix (Dent & Estrada-Villegas, 2021), the presence of a seed bank or the resprouting of remnant vegetative structures (Purata, 1986; Guevara & Laborde, 1993; Bartha, Meiners, Pickett, & Cadenasso, 2003; Vieira & Scariot, 2006). In the case of M. acantholoba var. eurycarpa , no seed bank has been found in the Nizanda tropical dry forest (Meave et al. 2012; Mena, 2009). Further, although seed rain was recorded for this species at the study site, the amount of seed produced was very low relative to the number of trees in the plots (Cervantes, 2018), suggesting that seed dispersal may only play a minor role in the establishment of aMimosa -dominated canopy. What is presently known is that M. acantholoba var. eurycarpa is the species that displays more resprouts in the early successional community (Lebrija-Trejos, 2004). These resprouts, being live tissues produced by previously existing individuals, usually with a well-developed root system, are able to grow and reproduce rapidly once anthropogenic disturbances stop, and represent a pathway for the increase in the species’ representation in the community. Hence, acknowledging the contribution of resprouting may help better understand M. acantholoba var. eurycarpa ’s population dynamics as a whole.

To gain insights into the role that population dynamics plays in the dominance of a pioneer species in a tropical dry forest, in this study we characterized and modeled the dynamics of M. acantholobavar. eurycarpa along a successional gradient. We did this by modeling this species’ vital rates and their changes over succession using data from permanent plots originally established to represent a chronosequence, but then monitored yearly over 13 years. We then assembled these models into an integral projection model (IPM) that accounted for both resprouting and recruitment, and estimated transient population growth rates. We predicted that, at the onset of succession, the environmental conditions would promote M. acantholoba var.eurycarpa ’s performance in the successional plots. Therefore, the population size of this species should increase during the early years of succession and decrease in later stages due to changes in environmental conditions in the forest interior.