Ecological quality of a forest in a state of succession based on structural parameters: A case study in an evergreen Amazonian-Andean forest, Ecuador

Abstract The evergreen forests of the Ecuadorian Amazon Region are altered by anthropogenic and natural factors. This provokes the need to look for tools that facilitate decision-making in support of restoration. We characterized the ecological structure and distribution of an evergreen Amazonian-Andean forest in the upper Puyo River micro-basin as a base for establishing an ecological quality index. The inventory was assessed using transects 0.1 ha (10 m × 100 m), registering the species with diameters at 1.30 m height ≥10 cm. We encountered a high degree of richness (30 families, 65 species and 322 individuals). The structural parameters indicated the predominance of a heterogeneous forest, with characteristics belonging to disturbed forests. A non-continuous vertical distribution pattern was found, determined by 78% of the species in a single stratum. The mixing ratio resulted in a higher proportion (1:5) for the lower class. The species Wettinia maynensis, Alchornea glandulosa, Miconia splendens, Piptocoma discolor and Inga velutina had the highest ecological value. The principal components analysis distinguished the abundance of species that had a high correlation with the sites and a distinct pattern was found in transect three. We developed the Structural Ecological Quality Index, which considers the social position of various species as well as their ecological importance, to reflect alterations in structural parameters. Abundance was concentrated in the 10–20 m strata (10–20 cm diameter class), which showed the presence of disturbance indicator species and a low ecological value. This indicated the real value of the historical succession of the forest, thus we recommend carrying out a restoration of this important reservoir.