ASSESSMENT OF STAND CHARACTERISTICS AND SOIL OF UPPER PARANA ATLANTIC FORESTS (PARAGUAY) REVEALS HIGH HABITAT HETEROGENEITY

Abstract

The Upper Parana Atlantic Forest (UPAF) harbours some of the most endangered ecosystems in the world. However, little data are available on UPAF ecosystems, constraining effective protection and restoration efforts. The objective of this study was to classify UPAF forests, focusing on the stand structure, tree species diversity, tree species composition, and soil properties and their relationships with stand characteristics. We established 71 plots (50 m × 20 m) distributed across eight protected areas in the Paraguayan UPAF and evaluated trees with diameter at breast height ≥ 10 cm and composite soil samples from 0–20 cm in depth. We identified four forest types with their corresponding indicator species. Among these forest types, we observed significant differences between stand structure and tree species diversity. We separated the soil properties into two axes, with essential elements and pH on one axis, and the balance of clay and sand contents on the other. We found significant relationships between essential elements and pH and individual density, and between the balance of clay and sand contents and tree species diversity. Our findings explain the heterogeneity of the tree community and contribute to our understanding of the UPAF, enabling science-based and better-focused forest conservation and restoration programmes.