Wood anatomy of dominant species with contrasting ecological performance in tropical dry forest succession

Environmental restrictions faced by successional species (those occurring in recovering vegetation) change gradually between early and late succession. In tropical dry forest (TDF), legume species dominate early succession, that is, accumulate more biomass than coexisting species, but later are gradually replaced by late successional species. Stem anatomical traits are involved in water conduction efficiency and safety, and thus biomass accumulation. We hypothesized that anatomical characteristics of dominant species may explain their status in their respective successional community. We analyzed the wood anatomy of TDF dominant successional species: Mimosa eurycarpa and M. tenuiflora (early successional), Lysiloma divaricatum (late successional), and Euphorbia schlechtendalii (successionally ambiguous). Anatomical variables and indices were estimated and compared between species through linear modeling. Unexpectedly, Mimosa species differed in porosity type, which is one characteristic linked to water stress tolerance. M. eurycarpa and L. divaricatum are ring-porous (an uncommon feature in tropical species), whereas M. tenuiflora and E. schlechtendalii displayed diffuse porosity. M. eurycarpa had the lowest vulnerability index (VI) and the highest relative hydraulic conductivity. Within-individual differences in relative water conduction in ring-porous species, driven by high vessel density in earlywood and low VI in latewood, likely represent a highly advantageous strategy in water-stressed successional environments.