The Atlantic Forest is a phytogeographic domain with a high rate of endemism and large species diversity. The Sapotaceae is a botanical family for which species identification in the Atlantic Forest is difficult. An approach that facilitates species identification in the Sapotaceae is urgently needed because this family includes threatened species and valuable timber species. In this context, DNA barcoding could provide an important tool for identifying species in the Atlantic Forest. In this work, we evaluated four plant barcode markers (matK, rbcL, trnH-psbA and the nuclear ribosomal internal transcribed spacer region -ITS) in 80 samples from 26 species of Sapotaceae that occur in the Atlantic Forest. ITS yielded the highest average interspecific distance (0.122), followed by trnH-psbA (0.019), matK (0.008) and rbcL (0.002). For species discrimination, ITS provided the best results, followed by matK, trnH-psbA and rbcL. Furthermore, the combined analysis of two, three or four markers did not result in higher rates of discrimination than obtained with ITS alone. These results indicate that the ITS region is the best option for molecular identification of Sapotaceae species from the Atlantic Forest.

O objetivo deste estudo foi averiguar a existência de uma possível transição florística ao longo de um gradiente altitudinal numa floresta serrana do sul da Bahia, Brasil. A área amostrada situa-se em uma zona de transição (leste-oeste) entre florestas ombrófilas e estacionais. Um transecto linear abrangendo um hectare (10 × 1.000 m) foi situado na encosta da serra (de ca. 350 a 750 m.s.m.). Todas as árvores e lianas com DAP > 5 foram numeradas, coletadas e medidas. Foram calculados valores de densidade, dominância, frequência e valor de importância (VI) para cada espécie amostrada. Foram amostrados 1.400 indivíduos agrupados em 264 espécies e 56 famílias de angiospermas. Cariniana legalis (Mart.) Kuntze teve o maior VI, devido à elevada dominância de poucos indivíduos. Discocarpus pedicellatus Fiaschi & Cordeiro e Ampelocera glabra Kuhlm. foram as espécies mais frequentes, com 90 e 86 indivíduos respectivamente. Noventa e seis espécies foram representadas por apenas um indivíduo. As famílias mais diversas foram Fabaceae e Myrtaceae com 37 e 31 espécies respectivamente. Análises de agrupamento e correspondência (DCA) revelaram que a composição florística da floresta situada na porção mais alta do transecto foi distinta da restante. As florestas de porções mais baixas e mais altas do fragmento puderam ser consideradas respectivamente como semideciduais e ombrófilas. Embora haja diferenças florísticas evidentes entre essas florestas, ambas estão claramente vinculadas ao setor sul-Baiano da Mata Atlântica.

The purpose of this study was to attempt to detect a floristic transition in forest along an altitudinal gradient on a mountain side in southern Bahia, Brazil. The study site is located at the east-west transition from tropical moist to semideciduous forests. A belt transect of one hectare (10 × 1000 m) was established running up the slope (from ca. 350 m to 750 m elevation). All included trees and lianas > 5 cm in diameter at breast height were numbered, collected, and measured. Density, dominance, frequency, and importance values (IV) were calculated for each species. We encountered 1400 individuals and 264 species of woody plants in 56 families. Cariniana legalis (Mart.) Kuntze had the highest IV, based on the dominance of a small number of trees. Discocarpus pedicellatus Fiaschi & Cordeiro and Ampelocera glabra Kuhlm. were the most frequent trees, with 90 and 86 individuals respectively. Ninety-six species were represented by a single individual. The Fabaceae and Myrtaceae were the most diverse families with 37 and 31 species respectively. Cluster analysis and correspondence analysis (DCA) revealed that the composition of the forest along the uppermost 30 percent of the transect was distinct from the rest. The lower and upper forests can be considered respectively as semideciduous and moist forests. Although there are some well-marked floristic differences between these forests, both clearly belong to the southern Bahian sector of the Atlantic coastal forests.