Variación del stock de biomasa aérea de coberturas vegetales del paisaje en la transición del Bosque húmedo a seco tropical

Abstract

Transitional zones (TZs) are key areas where contrasting ecosystems converge, influencing landscape heterogeneity and biodiversity conservation. Their analysis is essential for understanding ecological changes in both natural and transformed landscapes. This study assessed diversity, forest structure, landscape configuration, and aboveground biomass (AGB) in a transitional zone between the tropical humid forest (THF) and the tropical dry forest (TDF) in the Colombian Caribbean. Based on a multiscale analysis, the TZ was first identified through a spatial analysis of climatic variables from vegetation sampling plots. A principal component analysis (PCA) was used to select the most relevant climatic variables, followed by a multivariate clustering. Variation in AGB along the ecosystem gradient was determined through floristic characterization of natural and transformed land covers, inferential and descriptive analyses, and generalized linear mixed models (GLMMs). Relationships between AGB, climatic variables, landscape metrics, and tree taxonomic diversity were explored using redundancy analysis (RDA) and variance tests. The results showed that 88.3% of the climatic variability in the transition was explained by relative humidity (RH), precipitation (PP), solar radiation (Rad), and evapotranspiration (Evap), allowing the identification of four zones, two of which comprise the TZ. AGB was significantly higher, as was forest diversity, patch area, and perimeter, in the THF and TZ compared to the TDF, reflecting its degradation. Species richness and Shannon diversity were slightly higher in the TZ compared to the THF and significantly higher than in the TDF. Likewise, AGB decreased with increasing Euclidean distance and shape index, although significantly from the TZ to the TDF. Taxonomic diversity explained 65.91% of the variation in AGB, while climatic and landscape variables accounted for 10.89% of its variation. These findings highlight the importance of including TZs in management and conservation strategies, given their essential role in maintaining the functionality and sustainability of sensitive and disturbed landscapes. Their high biodiversity value results from the overlap of THF and TDF species with distinct floristic arrangements. Moreover, they demonstrate differentiated productivity capacity (AGB) and a key role in ecosystem service provision.