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.