Consistent patterns of common species across tropical tree communities

Trees structure the Earth’s most biodiverse ecosystem, tropical forests. The vast number of tree species presents a formidable challenge to understanding these forests, including their response to environmental change, as very little is known about most tropical tree species. A focus on the common species may circumvent this challenge. Here we investigate abundance patterns of common tree species using inventory data on 1,003,805 trees with trunk diameters of at least 10 cm across 1,568 locations1,2,3,4,5,6 in closed-canopy, structurally intact old-growth tropical forests in Africa, Amazonia and Southeast Asia. We estimate that 2.2%, 2.2% and 2.3% of species comprise 50% of the tropical trees in these regions, respectively. Extrapolating across all closed-canopy tropical forests, we estimate that just 1,053 species comprise half of Earth’s 800 billion tropical trees with trunk diameters of at least 10 cm. Despite differing biogeographic, climatic and anthropogenic histories7, we find notably consistent patterns of common species and species abundance distributions across the continents. This suggests that fundamental mechanisms of tree community assembly may apply to all tropical forests. Resampling analyses show that the most common species are likely to belong to a manageable list of known species, enabling targeted efforts to understand their ecology. Although they do not detract from the importance of rare species, our results open new opportunities to understand the world’s most diverse forests, including modelling their response to environmental change, by focusing on the common species that constitute the majority of their trees

Influence of cutting room temperature on the microbiological quality of chicken breast meat

ABSTRACT The temperature control in the processing room is one of the major factors associated with the production of safe food with a satisfactory microbiological quality. A total of 288 samples of skinless chicken breast meat were placed in a cutting room, subjected to four different temperatures (12ºC, 14ºC, 16ºC and 18ºC) and collected to evaluate the influence of the room temperature on the microbiological quality during the cutting and boning of chicken breasts. Aerobic mesophilic microorganisms were counted to evaluate the environmental contamination. In addition, coliforms at 35ºC and 45ºC and Staphylococcus spp. were counted, and an analysis for the presence of staphylococcal enterotoxins and Salmonella spp. was performed to determine the microbiological quality of the meat. The results showed an increase in environmental contamination (P=0.01) with an increase in room temperature. However, no significant differences (P˃0.05) were observed in the meat cuts regarding the counts of coliforms at 35ºC and 45ºC, the count of Staphylococcus spp. and the presence of Salmonella spp. Moreover, no staphylococcal enterotoxins were detected in the samples analyzed. Thus, despite increasing the environmental contamination, the increase in the cutting room temperature did not affect the microbiological quality of the final product