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 locations 1–6 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 histories 7, 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

Case Study: Rosai-Dorfman Disease and Its Multifaceted Aspects

Daniela Oliveira Werneck Rodrigues,1,2 Roberta Wolp Diniz,2 Leonardo Cunha Dentz,1 Monica de Albuquerque Costa,3 Roberto Heleno Lopes,2 Lucas Fernandes Suassuna,4 Jane Rocha Duarte Cintra,2 Christian Domenge2 1Department of Medicine, Centro Universitário Presidente Antônio Carlos, Juiz de Fora, MG, Brazil; 2Department of Oncohematology, Hospital 9 de Julho/ Instituto Oncológico de Juiz de Fora, Juiz de Fora, MG, Brazil; 3Department of Dematology, Secretaria de Saúde da Prefeitura Municipal de Juiz de Fora, Juiz de Fora, MG, Brazil; 4Department of Medicine, Universidade Federal de Juiz de Fora (UFJF), Juiz de Fora, MG, BrazilCorrespondence: Daniela Oliveira Werneck Rodrigues, Instituto Oncológico de Juiz de Fora, R. Santos Dumont, 56 - Granbery, Juiz de Fora, MG, 36010-510, Brazil, Tel +553232573126, Email [email protected]: Rosai-Dorfman Disease (RDD) is a rare non-Langerhans histiocytosis, usually self-limited and presenting with massive, painless, bilateral cervical lymphadenopathy, with or without constitutional symptoms. Extranodal disease is frequently present, and may happen in the absence of lymph node involvement, symptomatology and differential diagnosis will depend on the site affected and fatal cases may occur. The authors present two cases of Rosai-Dorfman disease (RDD), diagnosed through immunohistochemistry, with different progressions, one with complete remission and one culminating in death, highlighting the variety of presentations and the diagnostic difficulty. RDD is a rare condition with clinical presentations similar to several diseases, and should be considered in the differential diagnosis of lymphadenopathy with extranodal lesions.Keywords: Rosai Dorfman disease, immunohistochemistry, diagnosis, differential diagnosis (MeSH-NCBI