Drought and herbivory as modulators of intraspecific differentiation in seedlings of a mountain tree

MARCORA, P I; ZEBALLOS, S R; FERRERAS, A E; HENSEN, ISABELL; TECCO, P A

PLANT ECOLOGY

SPRINGER

Lugar: Berlin; Año: 2023

1385-0237

In mountain ecosystems, plant regeneration might be constrained by multiple factors that change along elevation gradientsand promote traits differentiation. Drought is a strong filter for seedling establishment that might be modified by herbivoryco-occurrence. Populations of the tree Maytenus boaria support lower soil moisture and higher herbivory pressure at lowelevations than at mid-elevations in Córdoba Mountains, central Argentina. Consequently, we expect that populations fromthe low elevation perform better in response to drought than populations from mid-elevations and that herbivory modifiesthese responses. Seedlings from the two elevation origins were exposed to two levels of simulated drought and herbivory ina greenhouse experiment. The selected elevations corresponded to the lowest edge of species distribution (with driest soilsand highest herbivory pressure) and the central mid-elevation. Performance-related variables, biomass allocation patternsand several morphological and physiological traits were measured. Mortality patterns and most of morphological and physiologicalvariables showed that drought is a stressful factor at the regeneration stage of M. boaria. The drought effect wasincreased by simulated herbivory in some variables (LMF, RM:SM and SPAD). In most variables, origin did not influenceseedling performance, suggesting that drought response of seedlings is independent of populations’ elevation. Only leafnumber and water potential were in line with our predictions and showed an origin response to drought.