Bosques monotípicos de Gonopterodendron sarmientoi: ambiente, genética y morfología de los palosantales

Abstract

Gonopterodendron sarmientoi is a native tree species from Chaco region forest that grows in mixed forest or in pure dense forests (palosantales). Due to habitat destruction and high exploitation, G. sarmientoi is threatened; hence, baseline information about the forests where the species grows is needed to guide future management and conservation programs. The objective of this article is to characterize the environment, genetic diversity and morphology of G. sarmientoi’s palosantales (n=10), in relation to the species’ mixed forests (n=14). For that, along the whole range of the species distribution, we compared the palosantales and mixed forests regarding their composition of plant species and site attributes (soil type and vegetation index), genetic diversity obtained with neutral markers, and leaf and tree morphological traits. The palosantales were characterized by having fewer companion species forests (mean 8; min. 1; max. 14), predominantly with shrub species, in relation to mixed forests (mean 10; min. 8; max. 13). The soils of the palosantales showed high content of clay and low levels of organic carbon and sand. The lowest nutrients sampled sites were palosantales located in the center-west of the species range, in the triple border Argentina-Bolivia-Paraguay, and in the palosantales on Bermejo river paleochannels (Argentina). The vegetation index confirmed the low productivity of palosantales forests (NDVI palosantales 0.38; NDVI mixed forests 0.51). The palosantales were similar in genetic diversity with respect to mixed forest (nucleotide diversity 0.00103 vs. 0.00120; Shannon index 0.89 vs. 1.02, respectively). Morphologically, G. sarmientoi trees in the palosantales were shorter and shrubbier than the mixed forest trees. The forests of G. sarmientoi require focused research that considers the singularities of each type of forest, allowing conservation of the species and the derived ecosystem services.