ABSTRACT High species diversity, large area, and taxonomically under-studied groups are some of the explanations for the frequent discovery of new species of plants during ecological field campaigns in the Amazon region. Some of these new species are already being threatened from unplanned urban expansion associated with deforestation and habitat loss. Here we describe Tovomita cornuta, a new species discovered during ecological studies in the white-sand campinaranas of the Amazon, which is also threatened. The species is endemic to the state of Amazonas, Brazil, where it occurs in the understory of forested campinaranas physiognomies and is easily recognized by its narrowly obovoid fruits with dilated free styles. We provide a description, taxonomic and ecological comments, assessment of conservation status, geographic distribution, phenology, and illustrations for the new species.

RESUMO As florestas de várzea estão sendo afetadas ao longo de séculos por diversas atividades antrópicas que põem em risco a integridade desse ecossistema, demandando estudos que propiciem sua conservação e restauração. O objetivo deste estudo foi caracterizar a morfologia de plântulas de três espécies pioneiras presentes na floresta de várzea do lago Catalão - AM: Cecropia latiloba Miq. (Urticaceae), Ficus insipida Willd. (Moraceae) e Allophylus amazonicus (Mart.) Radlk. (Sapindaceae) como subsídio para criar ferramentas para sua identificação em campo. Para cada espécie foram coletadas sementes de três diferentes matrizes, as quais foram processadas e acondicionadas em bandejas para germinação em solo proveniente do local de coleta. Foram analisadas e descritas morfologicamente cada fase de desenvolvimento até a formação de plântulas e mudas. Nas três espécies, a germinação foi classificada como epígea e fanerocotiledonar, e todas apresentaram diferenças morfológicas nos cotilédones, eófilos e catáfilos, permitindo a separação visual das mesmas. Os resultados indicam que a morfologia foliar é uma importante ferramenta para auxiliar a identificação e diferenciação desde as fases iniciais do desenvolvimento das plântulas. Esse conhecimento pode subsidiar estratégias de manejo como a formação de banco de plântulas para a recuperação de áreas degradadas de várzea.

ABSTRACT The white-water floodplain forests (várzea) have been affected for centuries by various human activities that endanger the integrity of this ecosystem, demanding studies that provide conservation and restoration. The objective of this study was to characterize the seedling morphology of three pioneer species present in the floodplain forest of Catalão Lake - AM: Cecropia latiloba Miq. (Urticaceae), Ficus insipida Willd. (Moraceae), Allophylus amazonicus (Mart.) Radlk. (Sapindaceae), as a subsidy to create tools for the field identification. Seeds were collected from three different matrices, these were processed and placed in trays for germination in soil from the collection site. Each developmental phase until the seedling formation was analyzed and morphologically described. In the three species, the germination was classified as epigeal and phanerocotyledonous, and all showed morphological differences in cotyledons, eophylls and cataphylls, allowing the visual separation of them. Our results indicate that the leaf morphology is an important tool to help the identification and differentiation from the early stages of the seedling development. This knowledge can support management strategies such as the formation of a seedling bank for the recovery of degraded várzea forests areas.

ABSTRACT Aquatic herbaceous plants are especially suitable for mapping environmental variability in wetlands, as they respond quickly to environmental gradients and are good indicators of habitat preference. We describe the composition of herbaceous species in two oligotrophic wetland ecosystems, floodplains along black-water rivers (igapó) and wetlands upon hydromorphic sand soils (campinarana) in the Parque Nacional do Jaú and the Reserva de Desenvolvimento Sustentável Uatumã in Central Amazonia, both protected areas. We tested for the potential distribution range (PDR) of the most frequent species of these ecosystems, which are the ones that occurred in at least two of the sampled wetlands, using species distribution models (SDMs). In total, 98 aquatic herbaceous species were recorded, of which 63 occurred in igapós and 44 in campinaranas. Most igapó species had ample PDRs across the Neotropics, while most campinarana species were restricted to the Amazon Basin. These results are congruent with studies that described similar distribution patterns for tree and bird species, which emphasizes a high degree of endemism in Amazonian campinaranas. However, we also found differences in the potential distribution of species between the two protected areas, indicating high environmental variability of oligotrophic ecosystems that deserve further investigation to develop effective measures for their conservation and protection.

ABSTRACT Amazon wetlands are among the most vulnerable ecosystem to be impacted by climate change, which may increase the frequency of extreme droughts and floods. We used Eichhornia crassipes and Pistia stratiotes, two abundant aquatic plants in the Amazon floodplains, to evaluate the effects of combined temperature and [CO2] increase on growth, physiology and ecological interactions. Individual and paired plants were deposited for three weeks in a microcosm under four IPCC scenarios: control (current temperature/CO2), mild (control + 1.5 ºC, 200 ppm CO2), intermediate (control + 2.5 ºC, 450 ppm CO2) and extreme (control + 3.5 ºC, 850 ppm CO2). P. stratiotes died after three weeks in the intermediate and extreme treatments; E. crassipes experienced no mortality or change in any of the measured variables during the same period. P. stratiotes reduced root length in the mild treatment and reduced total dry biomass in intermediate and extreme treatments, revealing less tolerance to climate change. Ecological interactions between the two species changed with increasing [CO2] and temperature neutral interaction changed to facilitation for E. crassipes, while competitive interaction changed to neutral for P. stratiotes. Global climate change may alter the composition, biomass and ecological interactions of Amazonian aquatic plant species.

RESUMO A super-exploração madeireira é uma das principais causas de perda da biodiversidade e extinções locais. Na Amazônia brasileira o uso intensivo focado em poucas espécies tem levado à redução de suas populações e à substituição destas espécies, consideradas “nobres” pelo mercado madeireiro, por espécies “menos nobres” com populações ainda viáveis para exploração. Nós realizamos entrevistas com moradores de duas comunidades em uma reserva de desenvolvimento sustentável na Amazônia Central, e usamos listas livres e o Índice de Saliência Cognitiva (S) para elucidar percepções dos moradores sobre a exploração madeireira local e identificar possíveis espécies em risco em florestas de campinarana e terra-firme. Além disso, para inferir possíveis consequências da atividade madeireira, avaliamos o atual status populacional das espécies madeireiras citadas pelos moradores em inventários florestais realizados dentro da reserva. Os resultados do S e os relatos dos moradores sugerem o uso intensivo de espécies madeireiras de terra-firme e um aumento aparentemente recente da exploração de espécies de campinarana, antes desprezadas pelo baixo valor comercial. Os inventários mostram que espécies madeireiras de campinarana têm altas densidades relativas e baixos valores de S, em contraste com espécies de terra-firme, que, em sua maioria, apresentam baixas densidades relativas e altos valores de S. Nossos resultados ressaltam a necessidade de identificar e monitorar as populações de espécies madeireiras importantes, tanto em florestas de terra-firme quanto em campinaranas, e de involver os comunitários no desenvolvimento de políticas de manejo da exploração madeireira na reserva.

ABSTRACT Overexploitation is one of the main causes of biodiversity loss and local extinction. In the Brazilian Amazon, the intensive use of high-value timber species is leading to a decline in their populations. When in decline, these species can be replaced by less valuable and more common ones that are more feasible to exploit. We conducted interviews with residents of two communities in a sustainable development reserve in central Amazonia, and used free lists and the cognitive salience index (S) to assess the perceptions of residents regarding the occurrence and purpose of timber exploitation, and to identify possible endangered species in white-sand and terra-firme forests. In addition, to infer possible consequences of logging, we assessed the current population status of timber species cited by residents in forest-plot inventories carried out within the reserve. S-index values and interviewee reports suggested an intensive use of terra-firme timber species and an apparently recent increase in the exploitation of white-sand species, which did not use to be exploited because of their relatively low commercial value. The inventories showed that the white-sand timber species have high relative densities and low S values in contrast to the terra-firme species, which mostly have low relative densities and high S values. Our results highlight the need to identify and monitor relevant timber species in both terra-firme and white-sand forests, and to increase the involvement of the local community in the development of logging management practices.

RESUMO As campinaranas amazônicas apresentam uma série de características únicas, como a dominância de poucas espécies, alto grau de endemismos e baixa riqueza de espécies, que as diferenciam de outras formações florestais amazônicas. Parâmetros edáficos têm sido apontados como os principais responsáveis pelas características das campinaranas. Contudo, como estes parâmetros influenciam a composição, riqueza e estrutura deste tipo de vegetação ainda é pouco entendido. Neste estudo investigamos a variação estrutural, a composição florística e a relação solo-vegetação em três áreas de campinarana na Amazônia central, com intuito de testar se pequenas diferenças nos parâmetros edáficos do solo estão relacionados com diferenças na composição, riqueza e estrutura do componente arbóreo em áreas de campinarana adjacentes. Em cada área foram amostradas três parcelas de 50 x 50 m (totalizando 2.25 ha), com o critério de inclusão para os indivíduos de DAP ≥ 5 cm. Amostras de solo foram coletadas em cada parcela. O número total de indivíduos amostrados foi 3956, pertencendo a 40 famílias e 140 espécies. Em cada área poucas espécies foram dominantes, mas estas variaram entre as áreas. Diferenças entre as áreas foram significativas, porém parcelas da mesma área tenderam a ter composição florística similar. A variável soma de bases (SB) foi diretamente relacionada à composição de espécies; contudo, riqueza de espécies e estrutura florestal não foram relacionadas a nenhum dos parâmetros do solo amostrados. Concluimos que mesmo pequenas variações nos parâmetros edáficos do solo podem mudar a composição de espécies em campinaranas, embora esta variação não necessariamente influencie a riqueza e outros parâmetros estruturais da vegetação.

ABSTRACT The Amazonian white-sand vegetation presents a set of unique features, such as the dominance of a few species, high endemism and low species richness, which differentiate it from other Amazonian forests. Soil parameters have long been recognized as the main drivers of white-sand vegetation (WSV) characteristics. However, how they influence the composition, richness and structure of this vegetation type is still poorly understood. In this study we investigated the variation in floristic composition between patches and the soil-vegetation relations in three central Amazonian WSV patches. We tested whether slight differences in soil properties are linked with differences in floristic composition, species richness and forest structure in adjacent patches. In each patch three plots of 50 x 50 m were sampled (a total of 2.25 ha). Soil samples were collected for each plot. The sampling cutoff for arboreal individuals was DBH ≥ 5 cm. We sampled a total of 3956 individuals belonging to 40 families and 140 species. In each patch only a few species were dominant, but the dominant species varied among patches. Differences among patches were significant, but plots in the same patch tended to have similar species composition. The variable sum of bases (SB) was directly related to species composition, however, species richness and forest structure were not related to soil parameters. Even small variations in soil parameters can change species composition in WSV, although these variations do not necessarily influence the richness and other structural parameters.