Explore the vast range of titles available.

Aim We studied global variation in beta diversity patterns of lake macrophytes using regional data from across the world. Specifically, we examined (1) how beta diversity of aquatic macrophytes is partitioned between species turnover and nestedness within each study region, and (2) which environmental characteristics structure variation in these beta diversity components. Location Global. Methods We used presence–absence data for aquatic macrophytes from 21 regions distributed around the world. We calculated pairwise-site and multiple-site beta diversity among lakes within each region using Sørensen dissimilarity index and partitioned it into turnover and nestedness coefficients. Beta regression was used to correlate the diversity coefficients with regional environmental characteristics. Results Aquatic macrophytes showed different levels of beta diversity within each of the 21 study regions, with species turnover typically accounting for the majority of beta diversity, especially in high-diversity regions. However, nestedness contributed 30–50% of total variation in macrophyte beta diversity in low-diversity regions. The most important environmental factor explaining the three beta diversity coefficients (total, species turnover and nestedness) was elevation range, followed by relative areal extent of freshwater, latitude and water alkalinity range. Main conclusions Our findings show that global patterns in beta diversity of lake macrophytes are caused by species turnover rather than by nestedness. These patterns in beta diversity were driven by natural environmental heterogeneity, notably variability in elevation range (also related to temperature variation) among regions. In addition, a greater range in alkalinity within a region, likely amplified by human activities, was also correlated with increased macrophyte beta diversity. These findings suggest that efforts to conserve aquatic macrophyte diversity should primarily focus on regions with large numbers of lakes that exhibit broad environmental gradients.

The majority of vascular plants are mycorrhizal: 72% are arbuscular mycorrhizal (AM), 2.0% are ectomycorrhizal (EcM), 1.5% are ericoid mycorrhizal and 10% are orchid mycorrhizal. Just 8% are completely nonmycorrhizal (NM), whereas 7% have inconsistent NM–AM associations. Most NM and NM–AM plants are nutritional specialists (e.g. carnivores and parasites) or habitat specialists (e.g. hydrophytes and epiphytes). Mycorrhizal associations are consistent in most families, but there are exceptions with complex roots (e.g. both EcM and AM). We recognize three waves of mycorrhizal evolution, starting with AM in early land plants, continuing in the Cretaceous with multiple new NM or EcM linages, ericoid and orchid mycorrhizas. The third wave, which is recent and ongoing, has resulted in root complexity linked to rapid plant diversification in biodiversity hotspots.

Najas is a cosmopolitan genus belonging to the family Hydrocharitaceae; Najas marina is a submerged aquatic herbaceous species, with prickly stems and leaves, living in fresh or brackish waters of shallow lakes. The aim of this work was to report the presence of N. marina in an urban lake in the city of San Miguel de Tucumán (Tucumán, Argentina), being the first record of the genus in northwestern Argentina. Previous reports of N. marina in Argentina included the provinces of Corrientes, Mendoza, Misiones, San Luis and Santa Fe. Specimens collected in the northeast of the country (provinces of Corrientes and Santa Fe) previously cited as N. marina correspond to Najas major, characterized by having unarmed stems and leaves. Najas es un género cosmopolita perteneciente a la familia Hydrocharitaceae; Najas marina es una especie herbácea acuática sumergida, con tallos y hojas armados con aguijones, que vive en aguas dulces o salobres de lagos poco profundos. El objetivo de este trabajo fue reportar la presencia de N. marina en un lago urbano de la ciudad de San Miguel de Tucumán (Tucumán, Argentina), siendo el primer registro del género en el noroeste argentino. Reportes previos de N. marina en Argentina incluyeron las provincias de Corrientes, Mendoza, Misiones, San Luis y Santa Fe. Los especímenes colectados en el noreste del país (provincias de Corrientes y Santa Fe) previamente citados como N. marina corresponden a Najas major, caracterizada por tener tallos y hojas sin aguijones.

Abstract This study provides a floristic survey of aquatic macrophytes in the Quilombola community of Saco das Almas, located in the municipality of Brejo, eastern Maranhão, Brazil. We carried out eleven quarterly field expeditions between January 2023 and March 2025. We recorded 100 species of aquatic macrophytes, distributed across 40 families and 70 genera, including the first record of Luziola bahiensis (Steud.) Hitchc. (Poaceae) for the state and the rare and critically endangered Griffinia nocturna Ravenna (Amaryllidaceae). This is the most extensive floristic inventory currently available on aquatic macrophytes in the Cerrado wetlands of Maranhão. Cyperaceae, Fabaceae, and Melastomataceae were the most species-rich families, while exclusively emergent and amphibious life forms predominated (~70% of species). Our results fill long-standing gaps in the knowledge of Maranhão’s aquatic flora, particularly in its Cerrado region, and highlight the need to extend surveys to other Cerrado and Amazonian wetlands in the state. The inventory establishes a robust baseline for biodiversity monitoring and provides important data to advance ecological research, guide taxonomic studies, and inform wetland conservation strategies in Maranhão. Resumo Este estudo apresenta um levantamento florístico de macrófitas aquáticas na comunidade quilombola de Saco das Almas, localizada no município de Brejo, leste do Maranhão, Brasil. Realizamos onze expedições trimestrais de campo entre janeiro de 2023 e março de 2025. Registramos 100 espécies de macrófitas aquáticas, distribuídas em 40 famílias e 70 gêneros, incluindo o primeiro registro de Luziola bahiensis (Steud.) Hitchc. (Poaceae) para o estado e a rara e criticamente ameaçada Griffinia nocturna Ravenna (Amaryllidaceae). Este é o inventário florístico mais extenso atualmente disponível sobre macrófitas aquáticas nas áreas úmidas do Cerrado maranhense. Cyperaceae, Fabaceae e Melastomataceae foram as famílias mais ricas em espécies, enquanto formas de vida exclusivamente emergentes e anfíbias predominaram (~70% das espécies). Nossos resultados preenchem lacunas históricas no conhecimento da flora aquática do Maranhão, particularmente em sua região de Cerrado, e destacam a necessidade de ampliar os levantamentos para outras áreas úmidas do Cerrado e da Amazônia no estado. O inventário estabelece uma base robusta para o monitoramento da biodiversidade e fornece dados importantes para o avanço de pesquisas ecológicas, a orientação de estudos taxonômicos e o embasamento de estratégias de conservação das áreas úmidas no Maranhão.

Aims The carnivorous Utricularia (Lentibulariaceae) has an anatomically simple and seemingly rootless vegetative body. It occupies a variety of wetlands and inland waters and shows a broad range of life forms. Here, we aimed to elucidate structural and functional traits in various hydric conditions. Furthermore, we intended to evaluate morpho-anatomical adaptations in correlation with life forms. Methods Morpho-anatomical characteristics typical for hydrophytes of all life forms were investigated by light microscopy on 13 Utricularia taxa, compared to one Pinguicula and two Genlisea taxa, and assessed by multivariate analyses. Results Vegetative structures of Utricularia and Genlisea showed reduced cortical, supporting, and vascular tissues. With increasing water table, leaves were thinner, and narrower or dissected, and submerged organs tended to contain chloroplasts in parenchymatic and epidermal cells. In some main stolons, an endodermis with Casparian strips was visible. Large gas chambers, including a novel ‘crescent’ and a special ‘hollow’ aerenchyma pattern, were found in amphibious to free-floating taxa. Conclusions The evolutionary transfer of carnivory from aerial to subterranean organs in Genlisea , and even more in Utricularia , coincides with a highly simplified anatomy, which is adapted to a broad variety of hydric conditions and compensates for structural innovations in the uptake of nutrients.

The persistent bioavailability of toxic metal(oids) (TM) is undeniably the leading source of serious environmental problems. Through the transfer of these contaminants into food networks, sediments and the aquatic environmental pollution by TM serve as key routes for potential risks to soil and human health. The formation of iron oxyhydroxide plaque (IP) on the root surface of hydrophytes, particularly rice, has been linked to the impact of various abiotic and biotic factors. Radial oxygen loss has been identified as a key driver for the oxidation of rhizosphere ferrous iron (Fe2+) and its subsequent precipitation as low-to-high crystalline and/or amorphous Fe minerals on root surfaces as IP. Considering that each plant species has its unique capability of creating an oxidised rhizosphere under anaerobic conditions, the abundance of rhizosphere Fe2+, functional groups from organic matter decomposition and variations in binding capacities of Fe oxides, thus, impacting the mobility and interaction of several contaminants as well as toxic/non-toxic metals on the specific surface areas of the IP. More insight from wet extraction and advanced synchrotron-based analytical techniques has provided further evidence on how IP formation could significantly affect the fate of plant physiology and biomass production, particularly in contaminated settings. Collectively, this information sets the stage for the possible implementation of IP and related analytical protocols as a strategic framework for the management of rice and other hydrophytes, particularly in contaminated sceneries. Other confounding variables involved in IP formation, as well as operational issues related to some advanced analytical processes, should be considered.

We studied community–environment relationships of lake macrophytes at two metacommunity scales using data from 16 regions across the world. More specifically, we examined (a) whether the lake macrophyte communities respond similar to key local environmental factors, major climate variables and lake spatial locations in each of the regions (i.e., within-region approach) and (b) how well can explained variability in the community–environment relationships across multiple lake macrophyte metacommunities be accounted for by elevation range, spatial extent, latitude, longitude, and age of the oldest lake within each metacommunity (i.e., across-region approach). In the within-region approach, we employed partial redundancy analyses together with variation partitioning to investigate the relative importance of local variables, climate variables, and spatial location on lake macrophytes among the study regions. In the across-region approach, we used adjusted R2 values of the variation partitioning to model the community–environment relationships across multiple metacommunities using linear regression and commonality analysis. We found that niche filtering related to local lake-level environmental conditions was the dominant force structuring macrophytes within metacommunities. However, our results also revealed that elevation range associated with climate (increasing temperature amplitude affecting macrophytes) and spatial location (likely due to dispersal limitation) was important for macrophytes based on the findings of the across-metacommunities analysis. These findings suggest that different determinants influence macrophyte metacommunities within different regions, thus showing context dependency. Moreover, our study emphasized that the use of a single metacommunity scale gives incomplete information on the environmental features explaining variation in macrophyte communities.

Aims Functional trait-based approaches have been widely used to explore the relationship between plants and their surroundings. Yet, whether phenotypic plasticity (the ability of plants to change their functional traits) and phenotypic integration (the coordinated relationship between functional traits of plants) are differently functional coordination mechanisms to enhance plant adaptation to declining water levels is still lacking in empirical knowledge. Methods We conducted a mesocosm experiment in an alpine wetland with two dominant plants, Carex muliensis (hygrophytes) and Pedicularis longiflora var. tubiformis (mesophytes), exposed to four water table gradients (WT10, WT0, WT-20 and WT-50, representing the water table at 10 cm, 0 cm, -20 cm and − 50 cm from the surface). We measured leaf traits related to resource use strategies, and the relationship between leaf phenotypic plasticity and integration. Results We found that hygrophytes shifted their leaf traits towards resource-conserving strategies, such as increasing leaf thickness and decreasing leaf area and specific leaf area, under water table decline. In contrast, mesophytes shifted their leaf traits towards resource-acquisition strategies, enhancing their competitiveness and fitness at low water levels. We also found a negative correlation between leaf phenotypic plasticity and integration in both plant species, suggesting a trade-off between them. which was attributed to the fact that wetland plants may prioritize traits that reduce water loss (e.g. larger leaf thickness), resulting in lower integration with other traits (photosynthetic and nutrient use related traits). Conclusions We conclude that, water table decline alters plant leaf resource use strategies and that the balance between leaf phenotypic plasticity and integration contributes to plant adaptation to water table decline. This study improves our understanding of the role of leaf phenotypic plasticity and integration in plant adaptation in the context of declining water levels in wetlands will help predict the future structure and composition of alpine wetland ecosystems.

The influence of the Intertropical Convergence Zone (ITCZ) in the emerging South Atlantic region during the late Aptian (Early Cretaceous) is reflected in the spatio-temporal distribution of plant communities recorded in eight Brazilian sedimentary basins. The distribution of the bioclimatic groups of hygrophytes, hydrophytes, tropical lowland flora, upland flora, and xerophytes was quantified using pollen and spores. A predominance of xerophytes from the tropical xerophytic shrubland biome characterized the pre-evaporitic, evaporitic, and post-evaporitic paleoclimatic phases, in particular the evaporitic phase. The region experienced humidity events in the pre-evaporitic and post- evaporitic phases, especially near the paleoequator, where the tropical rainforest biome with two phytophysiognomies (lowland and montane rainforests) prevailed. Increasing humidity had a positive effect on plant diversity.

Low-order streams and riparian wetlands are important contributors to the drainage network in the landscape. However, there has been little research into the nature of these ecosystems in Brazil. Our estimates show that riparian wetlands of low-order streams and other small associated wetlands cover at least 25% of the forested part of the Amazon basin and about 10% of the Cerrado region. Information on the semi-arid Caatinga is lacking, but ~ 3% of the area may be occupied by riparian wetlands and other small wetland types, many of which are periodically dry. Riparian vegetation includes a very large richness in tree species. The amount and species richness of herbaceous plants depend on light availability. In-streams of the semi-arid region of Brazil, hydrophytes are restricted by unpredictable flash floods and periodic drought. Aquatic food webs are largely based on the organic matter produced by the riparian vegetation. Large-scale agriculture and cattle ranching pose a serious threat to riparian wetlands, their biodiversity, and their function as a buffer in the hydrological cycle of the landscape. A nation-wide screening program would provide a more detailed picture and allow the elaboration of a national conservation and restoration program for the Brazilian riparia.