Edaphic factors and initial conditions influence successional trajectories of early regenerating tropical dry forests

Abstract

1. Edaphic factors and initial conditions can regulate the speed of forest succession.Edaphic factors, which include soil chemistry and topography, determine soil resource availability and can filter species as forests mature. Initial plant cover early in succession can determine the rates at which secondary forests change in structure, richness, biomass and composition over time. While some of the effects of edaphic factors and initial conditions on forest succession have been studied, how they simultaneously modify young regenerating tropical forest has rarely been examined.2. We surveyed 22 young forests plots in Panama for 7 years (11, 6 and 3-yearold stands when censuses began). We study how tree and liana species composition change early in succession, as well as how edaphic factors (soil nutrients and topography) and initial conditions (initial basal area and forest canopy cover) influence changes in tree and liana abundance, species richness, biomass and composition throughout succession.3. We found that edaphic factors and initial conditions explained up to 45% of the variation in the successional trajectories for trees and lianas. Soil nutrients had a significant positive effect on the changes in tree biomass accretion, while topography significantly contributed to community similarity of large lianas over time. Initial basal area had a significant negative effect on the changes in sapling abundance and tree richness over time and a positive marginal effect on tree biomass accretion. Forest canopy cover only had a positive marginal effect on changes in sapling abundance.4. Tree abundance, biomass and richness increased over time, while sapling abundance, biomass and richness remained stable or decreased, probably due to community thinning. However, changes over time of small and large lianas diverged, probably due to differential resource availability that affected lianas but not trees. 5.Synthesis. Soil fertility, topography and initial basal area influence early forest regeneration. Higher soil fertility can allow trees to fix carbon faster, and lianas might | 161Journal of Ecology ESTRADA-VILLEGAS ET AL.

The response of lianas to 20 yr of nutrient addition in a Panamanian forest

“…We found that lianas were increasing in our plots, but there was no support for the hypothesis that nutrient deposition contributes to observed liana increases. Our findings are consistent with observational studies (Dalling et al 2012, Ledo and Schnitzer 2014, Estrada‐Villegas et al 2020), which reported that soil nutrients and soil chemistry were poor predictors of liana abundance and distribution. Therefore, the distribution of lianas and their increase in neotropical forests are likely not the result of elevated nutrient deposition.…”

“…In the same 50-ha plot, Ledo and Schnitzer (2014) reported that habitat type, which combined edaphic and topographical variables (e.g., elevation, slope, curvature, and aspect), did not explain liana distribution or abundance. Because lianas did not respond to aggressive nutrient addition in this study, and previous studies have not found a strong response of lianas to soil chemistry and habitat type (Dalling et al 2012, Estrada-Villegas et al 2020, it is unlikely that nutrient deposition is a strong explanatory factor for either the distribution of lianas or the increase of lianas in this and in other tropical forests with similar soil-nutrient levels.…”

“…In Sabah, Malaysia liana basal area and species richness were higher in forests with relatively nutrient-rich alluvial soils compared to nutrient-poor sandstone and kerangas (heath) forest; however, liana density did not differ among forests (DeWalt et al 2006). By contrast, in Panama, soil chemistry had little effect on liana density, richness, or distribution in the Barro Colorado Island 50-ha plot (Dalling et al 2012, Ledo andSchnitzer 2014) and in 22 secondary dry forest plots (Estrada-Villegas et al 2020). In the only experimental study comparing the effects of nutrients on lianas and trees, phosphorus addition increased seedling photosynthetic performance for seven liana and six tree species in the shaded understory (in central Panama); however, the relative performance of lianas and trees did not differ (Pasquini et al 2015).…”

Monitoring tropical forest succession at landscape scales despite uncertainty in Landsat time series

“…A sizeable fraction of aboveground biomass is stored in trees outside forests (Graves et al 2018). Previous field work in our study region has demonstrated that fifteen‐years is a sufficient period of time to detect differences in metrics of succession between sites, including biomass accumulation and tree species richness (Estrada‐Villegas et al 2020).…”

Soil physicochemical property and arbuscular mycorrhizal fungi resilience to degradation and deforestation of a dry evergreen Afromontane forest in central Ethiopia

“…Tropical forests restoration can significantly be influenced by the levels of changes in soil physicochemical property (Ehleringer & Sandquist, 2006; Estrada‐Villegas et al, 2019; Harcombe, 1980; Long et al, 2018) and arbuscular mycorrhizal fungi (AMF) (Asmelash et al, 2016; Neuenkamp et al, 2018) from the pre‐disturbance status. Hence, the soil physicochemical property and AMF resilience studies to forest degradation and deforestation are considered to be a crucial initial step in forest restoration planning (Ayala‐Orozco et al, 2018; Carrillo‐Saucedo & Gavito, 2020; Carrillo‐Saucedo et al, 2018; Safar et al, 2019).…”