The high species richness of tropical forests has long been recognized, yet there remains substantial uncertainty regarding the actual number of tropical tree species. Using a pantropical tree inventory database from closed canopy forests, consisting of 657,630 trees belonging to 11,371 species, we use a fitted value of Fisher's alpha and an approximate pantropical stem total to estimate the minimum number of tropical forest tree species to fall between ∼ 40,000 and ∼ 53,000, i.e., at the high end of previous estimates. Contrary to common assumption, the Indo-Pacific region was found to be as species-rich as the Neotropics, with both regions having a minimum of ∼ 19,000-25,000 tree species. Continental Africa is relatively depauperate with a minimum of ∼ 4,500-6,000 tree species. Very few species are shared among the African, American, and the Indo-Pacific regions. We provide a methodological framework for estimating species richness in trees that may help refine species richness estimates of tree-dependent taxa.

The main objective of this study was to characterize the tree arboreal species composition and to compare secondary and mature forests of the Morro Grande Forest Reserve (Cotia, metropolitan region of São Paulo, Brazil). Based on this evaluation, we discuss the forest type classification and the conservation value of this Reserve. We used the point centered quarter method, sampling 2,400 trees in six different sites, three with secondary forests and three other ones with a predominance of mature forests. In each site, four blocks of 25 points were assessed, totalizing 100 points or 400 individuals. The blocks were 200 m apart from each other. Data were analyzed through cluster and Detrended Correspondence Analysis (DCA). Results showed differences among sites, essentially differentiating the secondary and mature sites. DCA and cluster analyses were particularly useful to detect characteristic species for these two main successsional stages. Among the 260 species observed, only 12 were sampled in the six sites. Richness and diversity were surprisingly high when compared with previous studies in the study region. The Shannon diversity values were among the highest in the state of São Paulo, with 4.75 nats/tree for the whole sampling, 4.25 nats/tree for the three secondary sites, and 4.54 nats/tree for the three mature sites. The studied forest may be essentially classified as "Dense Mountain Rain Forest" presenting species from the Araucaria mixed forest, and also from the semi-deciduous forest and Cerrado (woody savanna) region. Those results seem to confirm the hypothesis of a "high montane refuge" in drier climatic conditions in the past. The high richness and mixed composition of different floras highlighted the importance to preserve the Morro Grande forest.

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The Morro Grande Forest Reserve (10,870 ha) is one of the biggest forest areas in the Atlantic Plateau. This region was intensively deforested for agriculture, wood and charcoal production, and more recently by the expansion of urban areas. The Reserve is located in the cristalline Plateau of Ibiúna, just above the Paranapiacaba Mountain (860 -1075 m above sea level), in a transition region between the rainy climate from the Atlantic coast, and the seasonal climate from inland São Paulo state. As a consequence, species composition in Morro Grande Reserve combines elements from the tropical rainforest and the semideciduous forest. Despite this particularity, few studies were carried out in the forests from Morro Grande. It is only in 2000 that a group of scientist related to the BIOTA/FAPESP program began a systematic analysis of the species composition of different taxonomic groups, as well as the analysis of ecological processes related with forest regeneration. The present manuscript introduces a series of nine articles with the biological data obtained in the Reserve these last four years, and aims also to present an historical and abiotic description of the Reserve, highlighting aspects of the relief, geologic and pedological conditions, climate, hydrography, land use and land cover. .870 ha) é um dos maiores remanescentes florestais do Planalto Atlântico paulista, região que foi submetida a fortes pressões de desmatamento tanto para a agricultura quanto para a exploração da lenha e do carvão e, mais recentemente, para a expansão imobiliária. A RFMG situa-se sobre embasamento cristalino, justo acima da Serra de Paranapiacaba, em altitudes que variam de 860 a 1075 m, numa região de transição entre o clima pluvial tropical do litoral e da encosta Atlântica, com o clima estacional do interior do estado. Por conseguinte, suas florestas acabam tendo uma composição de espécies particular, com elementos das florestas ombrófila densa e mesófila semi-decidual. Apesar desta particularidade, não houve até recentemente praticamente nenhum estudo nas florestas do Morro Grande. Foi apenas a partir de 2000 que um grupo de pesquisadores, no contexto de um projeto temático vinculado ao programa BIOTA/FAPESP, procurou analisar de forma sistemática a composição de diferentes grupos taxonômicos, assim como caracterizar processos ecológicos associados com a regeneração florestal. Este artigo tem por objetivo introduzir uma série de nove artigos com os principais resultados dos levantamentos biológicos na RFMG, obtidos nos últimos quatro anos, assim como fazer uma caracterização do histórico e das condições abióticas na Reserva, em termos de embasamento geológico, pedológico, clima, hidrografia, e do uso e cobertura do território. Grande, Mata Atlântica, embasamento geológico, pedológico, clima, hidrografia, uso Palavras-chave: Reserva Florestal do Morro

RESUMO -(Estádio sucessional e fatores geográficos como determinantes da similaridade florística entre comunidades florestais no Planalto Atlântico, Estado de São Paulo, Brasil). A análise das relações de similaridade florística entre comunidades geralmente conduz ao estabelecimento de padrões, condicionados por fatores diversos que determinam a ocorrência ou não das espécies em diferentes locais. Em busca de tais padrões, foram analisadas as relações de similaridade florística entre comunidades florestais localizadas na região do Planalto de Ibiúna, estado de São Paulo, Brasil. Incluíram-se na análise 21 fragmentos florestais e seis sítios em uma Reserva Florestal contínua, sendo que a composição florística e a estrutura da comunidade arbórea (DAP mínimo 5 cm) em cada local foram amostradas pelo método de quadrantes. Aplicaram-se dois métodos de análises multivariadas: 1) Análise de Correspondência Destendenciada (DCA), com base no índice de similaridade de Sørensen; e 2) Divisão Hierárquica Dicotômica (TWINSPAN). A similaridade florística foi mais elevada entre comunidades em estádios sucessionais semelhantes, especialmente se estivessem geograficamente próximas. Há um gradiente florístico associado à latitude, indicando tratar-se de uma região de transição entre biomas. Nos sítios situados na face norte da região de estudo estão presentes espécies que também ocorrem no cerradão e em floresta estacional semidecidual, enquanto nos sítios situados na face sul prevalecem espécies características da floresta ombrófila densa.Palavras-chave: análises multivariadas, ecótono, fitogeografia, Mata Atlântica, sucessão secundária ABSTRACT -(Successional stage and geographic features determine floristic similarity among Atlantic Forest remnants, São Paulo State, Brazil). Analysis of floristic similarity relationships between plant communities can detect patterns of species occurrence and also explain conditioning factors. Searching for such patterns, floristic similarity relationships among Atlantic Forest sites situated at Ibiúna Plateau, São Paulo state, Brazil, were analyzed by multivariate techniques. Twenty one forest fragments and six sites within a continuous Forest Reserve were included in the analyses. Floristic composition and structure of the tree community (minimum dbh 5 cm) were assessed using the point centered quarter method. Two methods were used for multivariate analysis: Detrended Correspondence Analysis (DCA) and Two-Way Indicator Species Analysis (TWINSPAN). Similarity relationships among the study areas were based on the successional stage of the community and also on spatial proximity. The more similar the successional stage of the communities, the higher the floristic similarity between them, especially if the communities are geographically close. A floristic gradient from north to south was observed, suggesting a transition between biomes, since northern indicator species are mostly heliophytes, occurring also in cerrado vegetation and seasonal semideciduous forest, while southern indicator species ...

Epiphytes are hyper‐diverse and one of the frequently undervalued life forms in plant surveys and biodiversity inventories. Epiphytes of the Atlantic Forest, one of the most endangered ecosystems in the world, have high endemism and radiated recently in the Pliocene. We aimed to (1) compile an extensive Atlantic Forest data set on vascular, non‐vascular plants (including hemiepiphytes), and lichen epiphyte species occurrence and abundance; (2) describe the epiphyte distribution in the Atlantic Forest, in order to indicate future sampling efforts. Our work presents the first epiphyte data set with information on abundance and occurrence of epiphyte phorophyte species. All data compiled here come from three main sources provided by the authors: published sources (comprising peer‐reviewed articles, books, and theses), unpublished data, and herbarium data. We compiled a data set composed of 2,095 species, from 89,270 holo/hemiepiphyte records, in the Atlantic Forest of Brazil, Argentina, Paraguay, and Uruguay, recorded from 1824 to early 2018. Most of the records were from qualitative data (occurrence only, 88%), well distributed throughout the Atlantic Forest. For quantitative records, the most common sampling method was individual trees (71%), followed by plot sampling (19%), and transect sampling (10%). Angiosperms (81%) were the most frequently registered group, and Bromeliaceae and Orchidaceae were the families with the greatest number of records (27,272 and 21,945, respectively). Ferns and Lycophytes presented fewer records than Angiosperms, and Polypodiaceae were the most recorded family, and more concentrated in the Southern and Southeastern regions. Data on non‐vascular plants and lichens were scarce, with a few disjunct records concentrated in the Northeastern region of the Atlantic Forest. For all non‐vascular plant records, Lejeuneaceae, a family of liverworts, was the most recorded family. We hope that our effort to organize scattered epiphyte data help advance the knowledge of epiphyte ecology, as well as our understanding of macroecological and biogeographical patterns in the Atlantic Forest. No copyright restrictions are associated with the data set. Please cite this Ecology Data Paper if the data are used in publication and teaching events.

RESUMO -(Influência do relevo na riqueza de espécies arbóreas em fragmentos de floresta secundária de Mata Atlântica, SE, Brasil). O objetivo deste trabalho foi explorar a relação entre a riqueza de espécies arbóreas com as características morfológicas do relevo no Planalto de Ibiúna (SE, Brasil). Foram amostrados 61 blocos de 0,30 ha, sistematicamente estabelecidos em 20 fragmentos de floresta secundária (2-274 ha) e em três áreas de uma floresta secundária contínua, a Reserva do Morro Grande (9.400 ha). Em cada bloco, 100 árvores com diâmetro à altura do peito > 5 cm foram amostradas pelo método do quadrante centrado, e as riquezas total e por grupo de dispersão e sucessão foram obtidas. O relevo foi caracterizado pela média e variância da declividade, altitude, orientação e posição na vertente. Não houve relação significativa entre a heterogeneidade do relevo e a riqueza de espécies arbóreas. Os parâmetros do relevo afetaram pouco a riqueza da vegetação, mas a altitude foi particularmente importante, especialmente na floresta contínua. Apesar da pouca extensão na variação de altitude (150 m), a riqueza aumentou com este fator. As áreas mais altas também foram aquelas com as maiores coberturas florestais e os mais baixos graus de perturbação, o que deve contribuir para a maior riqueza dessas áreas. Nossos resultados indicam uma influência indireta do relevo, pelo fato das áreas mais altas serem também as menos desmatadas, e não uma influência direta de fatores abióticos relacionados ao gradiente de altitude.Palavras-chave: relevo, riqueza e composição de espécies arbóreas, Mata Atlântica, uso da terra ABSTRACT -(Relief influence on tree species richness in secondary forest fragments of Atlantic Forest, SE, Brazil). The aim of this work was to explore the relationship between tree species richness and morphological characteristics of relief at the Ibiúna Plateau (SE Brazil). We sampled 61 plots of 0.30 ha, systematically established in 20 fragments of secondary forest (2-274 ha) and in three areas within a continuous secondary forest site, Morro Grande Reserve (9,400 ha). At each plot, 100 trees with diameter at breast height > 5 cm were sampled by the point centered quarter method, and total richness and richness per dispersal and succession class were obtained. The relief was characterized by the mean and variance of slope, elevation, aspect and slope location. There was no significant relationship between relief heterogeneity and tree species richness. Relief parameters generally did not affect tree richness, but elevation was particularly important especially in the continuous forest. Despite the limited range of altitudinal variation (150 m), species richness increases with elevation. The highest areas were also those with the largest forest cover and the lowest disturbance degree, which should contribute to the greater richness of those sites. Our results suggest an indirect influence of relief, due to the fact that deforestation is less intense in higher regions, rather than a direct influence of abiotic...