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Populations of large frugivores are declining in tropical rainforests with potential consequences for carbon storage and climate.

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Amazonian forests are extraordinarily diverse, but the estimated species richness is very much debated. Here, we apply an ensemble of parametric estimators and a novel technique that includes conspecific spatial aggregation to an extended database of forest plots with up-to-date taxonomy. We show that the species abundance distribution of Amazonia is best approximated by a logseries with aggregated individuals, where aggregation increases with rarity. By averaging several methods to estimate total richness, we confirm that over 15,000 tree species are expected to occur in Amazonia. We also show that using ten times the number of plots would result in an increase to just ~50% of those 15,000 estimated species. To get a more complete sample of all tree species, rigorous field campaigns may be needed but the number of trees in Amazonia will remain an estimate for years to come.

The structure of the Atlantic Forest (AF) has been studied for almost 70 years. However, the related existing knowledge is spread over hundreds of documents, many of them unpublished and/or difficult to access. Synthesis initiatives are available, but they are restricted to only a few parts or types of the AF or are focused on species occurrence. Here, we conducted an extensive review to compile quantitative tree community surveys on all types of the AF until 2013 and to study where and how these surveys were conducted. We found 1157 relevant references, containing 2441 forest surveys published since 1945. These surveys corresponded to 2.24 million trees and 1817 ha of forests sampled. This total sampled area represents only 0.01 % of the AF remnants, showing how limited our knowledge is on AF structure. For Paraguay and the Brazilian states of Bahia and Mato Grosso do Sul this proportion was much smaller. The same was true for evergreen rainforests, Brejos de altitude and deciduous forests and most probably for the rare cloud, swamp, Caxetal and Mussununga forests for which no accurate remnant estimates were Communicated by Jefferson Prado, Pedro V. Eisenlohr and Ary T. de Oliveira-Filho.Electronic supplementary material The online version of this article (found. Since the 1980s, the amount of AF area sampled each year has increased continuously, but approximately 100 years will be necessary to sample at least 1 % of the AF. Thus, we urgently need an enormous amount of high-quality quantitative data to overcome our limited knowledge of the AF and to support conservation programs aiming to safeguard this threatened biodiversity hotspot.

Assessing the conservation value of restoration plantings is critical to support the global forest landscape restoration movement. We assessed the implications of tree species selection in the restoration of Brazil's Atlantic Forest regarding carbon stocking and species conservation. This assessment was based on a comprehensive dataset of seedling acquisition records from 961 restoration projects,  more than14 million seedlings, 192 forest remnants, and functional data from 1,223 tree species. We found that animal‐dispersed trees with larger seeds tend to have higher seed prices, yet are underrepresented in the seedlings acquired for restoration plantations. Compared to forest remnants, fruit supply potentially offered by the species acquired for restoration plantings is lower for birds, but higher for bats. Reduced abundance of medium‐ and/or large‐seeded, animal‐dispersed trees lead to declines of 2.8–10.6% in simulated potential carbon stocking. Given the uncertainty in these estimates, policy interventions may be needed to encourage greater representation of large‐seeded, animal‐dispersed tree species in Atlantic Forest restorations. These findings provide critical guidance for recovering tree functional diversity, plant‐frugivore mutualistic interactions, and carbon stocking in multi‐species tropical forest restoration plantings.

Tropical forests are being deforested worldwide, and the remaining fragments are suffering from biomass and biodiversity erosion. Quantifying this erosion is challenging because ground data on tropical biodiversity and biomass are often sparse. Here, we use an unprecedented dataset of 1819 field surveys covering the entire Atlantic Forest biodiversity hotspot. We show that 83−85% of the surveys presented losses in forest biomass and tree species richness, functional traits, and conservation value. On average, forest fragments have 25−32% less biomass, 23−31% fewer species, and 33, 36, and 42% fewer individuals of late-successional, large-seeded, and endemic species, respectively. Biodiversity and biomass erosion are lower inside strictly protected conservation units, particularly in large ones. We estimate that biomass erosion across the Atlantic Forest remnants is equivalent to the loss of 55−70 thousand km2 of forests or US$2.3−2.6 billion in carbon credits. These figures have direct implications on mechanisms of climate change mitigation.

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