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 However, the related existing knowledge is spread over hundreds of documents, many of them unpublished and/or difficult to access.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.

At the northern limits of the range of the palm species Euterpe edulis there is an endemic ecotype, known as the "Bahia" ecotype, which is distinguished by its reddish crownshaft and low seed production. Unfortunately, little is known about its demographic characteristics. Therefore, we contrasted the density of E. edulis populations in the Una region, in the southern part of the Bahia state, Brazil, with that of other populations of the species in southern and southeastern Brazil. In addition, within the Una region, we compared a long-protected forest fragment (F1) with three recently protected fragments (F2, F3, and F4), in terms of demographic parameters and plant size, in order to determine what influence, if any, time since protection has on E. edulis populations. Population densities within the Una region were higher than in regions where E. edulis populations are stressed by harvesting or intense seed predation but much lower than in regions with well protected populations. Among the Una fragments, density was highest in F1 and lowest in F2. The proportion of individuals at the various developmental stages differed among the fragments (χ²=25.219, df=12, p=0.014). Diameter at ground level, height, and number of leaves correlated positively among themselves and negatively with population density. For all developmental stages, F1 surpassed the other fragments in terms of densities and plant sizes. It is likely that the newly protected populations suffer the lingering effects of previous harvesting, which are reflected in their demography and in the size of their individual members. The viability of this low-density endemic ecotype must be established in order to assess the conservation status of the species on a regional scale.

Despite the general recognition that fragmentation can reduce forest biomass through edge effects, a systematic review of the literature does not reveal a clear role of edges in modulating biomass loss. Additionally, the edge effects appear to be constrained by matrix type, suggesting that landscape composition has an influence on biomass stocks. The lack of empirical evidence of pervasive edge-related biomass losses across tropical forests highlights the necessity for a general framework linking landscape structure with aboveground biomass. Here, we propose a conceptual model in which landscape composition and configuration mediate the magnitude of edge effects and seed-flux among forest patches, which ultimately has an influence on biomass. Our model hypothesizes that a rapid reduction of biomass can occur below a threshold of forest cover loss. Just below this threshold, we predict that changes in landscape configuration can strongly influence the patch's isolation, thus enhancing biomass loss. Moreover, we expect a synergism between landscape composition and patch attributes, where matrix type mediates the effects of edges on species decline, particularly for shade-tolerant species. To test our conceptual framework, we propose a sampling protocol where the effects of edges, forest amount, forest isolation, fragment size, and matrix type on biomass stocks can be assessed both collectively and individually. The proposed model unifies the combined effects of landscape and patch structure on biomass into a single framework, providing a new set of main drivers of biomass loss in human-modified landscapes. We argue that carbon trading agendas (e.g., REDD+) and carbon-conservation initiatives must go beyond the effects of forest loss and edges on biomass, considering the whole set of effects on biomass related to changes in landscape composition and configuration.

Primeiramente tenho que agradecer à minha família, pois foi o incentivo deles no momento em que eu queria desistir da pesquisa e da vida acadêmica que me deu forças para seguir em frente e tentar o doutorado. Obrigada mãe, Pri e Riven, meus irmãos amados, por não terem me deixado desanimar antes e durante o doutorado. Agradeço imensamente toda a paciência comigo nos inúmeros dias difíceis e pela compreensão quando eu não podia estar presente fisicamente nos momentos que eram importantes para vocês. Também agradeço à minha prima Carol pelas inúmeras conversas e conselhos durante esse processo, gratidão (rs)! Agradeço ao meu orientador Alexandre pela confiança depositada em mim e por ter se aventurado comigo no mundo da ecologia de paisagem e da conservação, apesar de não ser muito do seu agrado. Além disso, agradeço pela amizade e pela preocupação enquanto eu estava no sanduíche, não deixando que a burocrática da FAPESP atrapalhasse nossa vida.Também agradeço imensamente meu co-orientador Jean Paul por ter me aceitado nesse ambiente tão estimulante e acolhedor que é o Lepac, que acabou virando minha casa ao longo do doutorado. Obrigada por me ensinar o que é a ecologia de paisagem, pela paciência em me explicar tantas vezes conceitos e teorias de uma área que para mim foi um "admirável mundo novo" e por ser esse profissional que inspira a todos que trabalham contigo.Quiero agradecer a Victor Arroyo-Rodriguez por haberme aceptado en su laboratorio y permitirme tener la enriquecedora experiencia de vivir en México. Su pasión por la ciencia y compromiso con la investigación son admirables. Más que todo muchas gracias por su amistad, por acogerme en su familia, por su gran ayuda durante toda mi estadia en Mexico, por nuestros viajes y por una de las mejores navidades de mi vida! (gracias Yashua y familia)! Obrigada Marcelo Tabarelli e Milton Ribeiro pelas críticas, conselhos e conversas estimulantes nas reuniões do comitê de acompanhamento. Também agradeço muito ao Marcelo por me ajudar a definir a ideia geral da tese durante o EFA (2013) e pelas longas conversas discutindo ciência (e a tese) quando nos encontrávamos e por ter sido sempre tão solícito comigo.Obrigada também a todos os colaboradores desse estudo por terem acreditado e apoiado esse projeto e cedido os dados, sem os quais, eu não teria feito esse estudo. Grata pela confiança Felipe Melo, Eliana Cazetta, Larissa Rocha-Santos, Michaelle Pessoa, Deborah Faria, Luíz Fernando Magnago, Manuel Alejandro Hernández-Ruedas e Bráulio Santos.Grata à PPGE pelo ambiente tão estimulante e enriquecedor que é o da pós. Agradeço aos alunos da pós pela oportunidade de ser representante discente e, assim, de compreender melhor o funcionamento da pós e contribuir para seu desenvolvimento. Também agradeço aos coordenadores do curso de campo (Glauco, Dri e Paulo Inácio) por terem indeferido minha matrícula e assim me "forçado" a tentar o EFA. Obrigada a todos os funcionários do IB por fazerem a "coisa" funcionar, especialmente à Natália Targueta pela ajuda na revisão sistemát...

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