Introduction:

Dry and humid forests are among the most threatened on the planet in Colombia, they are in Critical Danger, but the status of the transitions is unknown.

Objective:

To establish the distribution, level of fragmentation, and floristic affinities of the transitional areas between the Tropical Dry Forest (TDF) and Tropical Wet Forest (TWF) in the climatic gradient of the Sinú River basin as a contribution to its conservation management.

Methods:

The Forest/Non-Forest (B/NB) layer of the study area was at a scale of 1 : 25 000 with Sentinel images (2021-2022) from Planet Scope and other sources, we identified the climatic regions, using climatic data from WorldClim 2.0 (1970-2000) and Giovanni 4.38 (2001-2021), we estimated the level of fragmentation, and we identified floristic affinities from liana sampling and a clustering analysis.

Results:

The basin has 462 972 ha of forests, 5 % are dry-humid transitional forests, 87 % are humid forests, 6 % are dry forests, and 2 % are mangrove forests. There are more than 1 000 ha of transitional forests in high-extreme fragmentation. The TWF has the lowest fragmentation (little-minimal) and the TDF is the most fragmented. The forested transitions of the basin are more floristically related to TDF.

Conclusions:

This study contributes to closing the gap in knowledge for determining the distribution patterns of transitional dry-humid tropical forests in the Sinú River basin by applying a replicable integrative methodology. These dry-humid transitional forests should be recognized as another important type of cover for the study of ecological processes under climate change scenarios. It is proposed that dry-humid forests should be included in conservation priorities in the planning and management processes of the territory at different geographic scales and management levels.