Well-sampled regions risk loosing key biological data: a case study in the Atlantic Forest.

The present study aimed to verify if important biological data are being lost in a well-sampled region due to areas neglected by most biodiversity surveys. We performed a floristic and structural survey of an Atlantic Forest located at the bottom of an escarpment, in the southern region of the state of Minas Gerais, Brazil. A total of 19 plots of 400 m² were allocated, totaling 0.76 ha of sampled area. All arboreal individuals with a diameter at breast height equal to or greater than 5 cm were sampled. We also collected surface soil samples for analysis. In order to evaluate the influence of edaphic factors and scarp on the tree community, a canonical correspondence analysis was performed. In order to analyze whether the studied forest is similar to or distinct from the rest of the region, a detrended correspondence analysis was carried out with 15 Atlantic Forest surveys located in the surroundings of the study area. The high floristic diversity and the structural variations found in the studied forest were attributed to the environmental heterogeneity due to the influences of the escarpment and the variations in the soil conditions, resulting in a forest with its own floristic composition and structure. The study suggested that important biological data are being lost in biodiversity surveys, even in well-sampled areas, due to neglected areas of difficult access. Thus, it is important the inclusion of these neglected sites in biodiversity inventories. [ABSTRACT FROM AUTHOR]