Biotic and abiotic drivers of seedling density in <italic>Polylepis rugulosa</italic> forests across east- and west-facing slopes in the Peruvian Andes.

BackgroundAimsMethodsResultsConclusions<italic>Polylepis</italic> forests are highly endangered tropical high Andean ecosystems. <italic>P. rugulosa</italic> has had the most significant decrease in spatial distribution compared to other Polylepis species and requires adequate restoration measures.This study evaluated the relationship between <italic>P. rugulosa</italic> seedling density and biotic and abiotic factors across east- and west-facing slopes to identify optimum conditions for the regeneration and restoration of the species.We assessed structural, edaphic, and topographic variables in 58 plots of 600 m2, microsite characteristics in 204 quadrats of 1 m2 and related them observed to <italic>P. rugulosa</italic> seedling density.The density and basal area of <italic>P. rugulosa</italic> adults were higher on west-facing slopes than on east-facing slopes. On both aspects, seedling density was positively related to the height and basal area of the adult trees and negatively related to sand content and the cover of ground vegetation (shrubs and herbs). Seedling density on east-facing slopes was positively related to soil organic matter content, and it was negatively related to it on west-facing slopes. Regarding microsite characteristics, the height of the nearest adult tree and litter cover were positively related to seedling density.Restoration of <italic>P. rugulosa</italic> should consider the contrasting effects of abiotic and biotic factors on seedling density on east- vs. west-facing slopes to optimise the recruitment and growth. [ABSTRACT FROM AUTHOR]