Structure and Tree Diversity in a Mixed Ombrophilous Forest Remnant, Southern Brazil

Abstract

This study aimed to determine the tree structure, floristic composition and species diversity in the Araucaria State Park, southern Brazil. We allocated 100 plots of 100 m 2 (1 ha) each one, and we recorded all trees with diameters at breast height ≥ 5 cm. We sampled 1368 individuals of 106 species, 75 genera and 44 families. Fabaceae, Lauraceae and Myrtaceae showed the greatest richness of species. The diversity of tree species was high (H '= 3.96), although the observed richness was less than the estimated one. The basal area was 46.88 m 2 ha -1 . We observed an intrinsic association between Araucaria angustifolia and Nectandra megapotamica, and a predominance of secondary and zoochorous (> 70%) species. Endangered and vulnerable species in the Santa Catarina state, such as Araucaria angustifolia, Cedrela fissilis, Dicksonia sellowiana and Ocotea porosa were sampled in the Park, highlighting its importance for the conservation of the Mixed Ombrophylous Forest.

Natural regeneration in a mixed ombrophilous forest remnant in southern Brazil

“…On a PEAR map 100 plots of 100 m 2 (10 m × 10 m) were allocated, seeking to represent all areas of the PEAR, but avoiding those that are difficult to access or particularly degraded (Passos et al 2021). These plots were later demarcated in the field.…”

“…The definition of the upper limit was based on the inclusion criterion (DBH ≥ 5.0 cm) most commonly used in surveys of tree canopy species in tropical forest (e.g. Klauberg et al 2010;Higuchi et al 2013;Passos et al 2021). For individuals not identified in the field, the collection and herborization of plant material was carried out for later identification through comparison with FURB herbarium specimens and assistance from specialists.…”

“…Shannon's diversity and Pielou's equability indexes were also calculated using the MATA NATIVA 2 program (Cientec 2006). We used the Sorensen index to assess the similarity between the tree (Passos et al 2021) and regenerating components. The species were classified according to the dispersal syndrome (Van der Pijl 1982) and according to the successional group in, pioneer, secondary or climax (Backes and Irgang 2002;Lorenzi 2008;Meyer et al 2013).…”

“…Although the IFFSC contemplated plots in the western region, all other studies were carried out in the midwest and south of SC, with a gap in knowledge about the natural regeneration of MOF in western SC. Passos et al (2021) studied the tree community in a MOF remnant in the western region of SC and recorded the occurrence of 106 species. Nectandra megapota mica (Spreng.)…”

“…and Podocarpus spp. Secondary (63%) and zoochorous (71%) species were the majority in the forest remnant (Passos et al 2021). This study investigated the structure and diversity of regenerating tree species in this same MOF remnant, aiming to answer the questions: Is the similarity between the regenerating and the tree components high?…”