Phytosociology of an open arboreal caatinga with high basal area in the Seridó desertification region, Brazil

ABSTRACT Seridó is one of the driest regions in the Caatinga biome, Northeastern Brazil, affected by a long history of anthropogenic impact, and today it is considered a desertification region. A phytosociological survey of woody species was carried out in an area at Morada das Jandairas Farm (MJF), in Santana do Seridó, Rio Grande do Norte, which still has a significant arboreal component despite maintaining an extensive cattle production, and compared it with data from other five inventories carried out in the region. Seventeen species from ten botanical families were found, with Fabaceae and Euphorbiaceae being the most diversified. Commiphora leptophloeos and Croton blanchetianus stood out as the most important species. The high floristic composition similarity among the six compared studies indicates that the different phytophysiognomies may be result of anthropogenic action and regeneration processes. The relatively high Basal Area in the MJF (26.8 m2 ha-1) stands out even considering inventories carried out throughout the Caatinga region, which is largely due to the presence of many large trees (C. leptophloeos). Considerations about the ecological importance of large and old trees are made, with recommendations for the methodology of phytosociological inventories.