Bianca Ott Andrade

Floras and botanical collections are essential tools for understanding plant diversity, promoting its conservation, and supporting a wide range of scientific applications. Uruguay, located in the biodiverse grassland region of southern South America, has had only an incomplete Flora, the most comprehensive of which was published more than a century ago. We review the country's flora and the history of its study, and introduce the new Flora Uruguaya Online (FUO; https://florauruguaya.org ), which when completed will provide a comprehensive record of all vascular plant species, including information on their distribution, morphological, ecological, and phenological characteristics. This online Flora presently contains information on 182 families, 1053 genera, and 3112 species, 85.4% of which are native to Uruguay and 2.2% endemic. Although Uruguay accounts for only 25% of the surface area of the Río de la Plata Grasslands, it contains over 60% of their species and more than 50% of their endemic taxa, reflecting its core geographical position. Uruguay's flora faces increasing pressure from land‐use change, habitat fragmentation, and invasive species. FUO provides critical support for addressing these challenges, offering systematic botanical data for basic and applied research, conservation, sustainable uses, and land management, including practical applications such as the identification of toxic plants affecting livestock production. We highlight key features of FUO with its research‐enabling tools for the exploration of Uruguay's botanical richness by scientists, as well as by policymakers, educators, conservationists, and citizens. These features include its accessibility, interactivity, multiple filters (e.g., geographic regions, ecological characteristics, conservation status, or specific species attributes), rich graphics, and multiple sources of data inputs tied to herbarium specimens.

Conservation strategies rely on precise taxonomic delimitation, yet delineating species complexes remains challenging. Despite these difficulties, it is crucial to protect vulnerable complexes. We examined the Poidium complex, comprising five morphologically similar taxa that co-occur in the highland grasslands of northeast Rio Grande do Sul, Brazil. Our goals were to assess whether morphological characters distinguish taxa or groups within the complex, evaluate correlations with environmental and geographic patterns, and inform conservation priorities. Using uni- and multivariate analyses of morphometric and environmental data, we identified three main groups within the complex, each defined by distinctive palea and lemma surface traits. Quantitative spikelet and lemma characters significantly differentiate these groups, and environmental and morphometric variables help characterize subgroups within the clusters. The majority of subgroups are concentrated in Northeast Rio Grande do Sul. Our results support circumscribing Poidium juergensii as having only strigose lemmas and no infraspecific delimitation, as well as treating individuals with glabrous lemmas at the species level, as Poidium tricholepis sp. nov. In addition, we highlight the weak morphological distinction between Poidium calotheca and Poidium ambiguum in sympatric areas. This study underscores the uniqueness of the South Brazilian highland grasslands and the relevance of including species complexes in conservation efforts.

Although ecosystem management and restoration are known to enhance carbon storage, limited knowledge of ecosystem‐specific soil organic carbon (SOC) stocks and processes hinders the development of climate‐ready, biodiversity‐focused policies. Baseline SOC stocks data for specific ecosystems is essential. This paper aims to: (i) examine SOC stock variability across major grassy ecosystems in Brazil and (ii) discuss data limitations and applications. We compiled the Grassland Synthesis Working Group dataset, which comprehensively aggregates SOC stocks data from published studies on main Brazil's grassy ecosystems. Our dataset results from systematic literature review and regional soil sampling datasets. The dataset provides spatially explicit SOC stocks, physical soil properties, and ancillary information from 182 studies (1996–2021) across 803 sites, spanning 35° latitude and 28° longitude. The dataset, structured in relational tables, reports soil C stocks and ancillary soil parameters at depths up to 100 cm. SOC stocks vary by grassy ecosystem types and sampling depth, with subtropical grasslands (Campos Gerais, South Brazilian highland grasslands, and Pampa) showing the highest SOC stocks across all depth layers (SOC 0–30 cm: 64.5–162.8 Mg C ha ⁻¹ ; SOC 0–100 cm: 137.6–224.7 Mg C ha ⁻¹ ). The tropical Cerrado and Amazon grassy ecosystems exhibit high SOC stocks, particularly in subsurface layers (SOC 0–30 cm: 53.6 and 38.3 Mg C ha ⁻¹ ; SOC 0–100 cm: 109.8 and 121.4 Mg C ha ⁻¹ , respectively). Our data analysis shows high carbon stocks in natural/seminatural ecosystems, but some ecosystems are undersampled. The dataset on SOC stocks in grassy ecosystems could greatly aid Brazil's national greenhouse gas inventory.

Our editorial introduces a Special Collection of scientific articles on current vegetation research in the most biodiverse of all biogeographic realms, the Neotropics. It contains nine scientific contributions dedicated to vegetation data, description and classification. Four research papers provide new vegetation classifications of important Neotropical biomes, namely the Arid Chaco in Argentina, Mexican temperate forests, and Andean wetlands in the Argentine Puna and southern Peru. Furthermore, one study provides a novel bioclimatic-vegetation classification approach applied to Mexican vegetation, while another proposes a new synthesis of the South American terrestrial biomes as geocomplexes. Finally, three vegetation databases are presented in the Special Collection: ArgVeg – Database of Central Argentina (GIVD ID: SA-AR-002), CACTUS – Vegetation database of the Dutch Caribbean Islands (GIVD ID: SA-00-004) and VegAndes: the vegetation database for the Latin American highlands (GIVD ID: SA-00-005). The Special Collection provides fundamental data and tools to better understand the diversity and complexity of Neotropical vegetation. Abbreviations: GIVD = Global Index of Vegetation-Plot Databases, IAVS = International Association for Vegetation Science, IAVS-LACS = IAVS Regional Section for the Latin America and the Caribbean, VCS = Vegetation Classification and Survey

Abstract— Improving species delimitation and knowledge on species complexes is crucial for many areas of study in Biology, especially conservation. Integrative taxonomy contributes to this topic by using different approaches to better delineate taxonomic boundaries. Metternichia (Solanaceae), historically a monospecific genus, has a geographic range that comprises contrasting environments. Metternichia principis was described as having two varieties: the typical variety, found in the humid forests of eastern Brazil (Atlantic Forest region), and M. principis var. macrocalyx, which presents a larger calyx and inhabits mostly semi-arid areas (Caatinga region). In this study, we tested the validity of such groups by integrating environmental, phenological, morphometric, and palynological data; applying uni- and multivariate tests; and evaluating the conservation status of each taxon. Our results support the recognition of two morphological groups within Metternichia, largely in agreement with the original circumscription of the varieties. Multivariate analyses clearly indicate different ecological niches, with each taxon inhabiting environments with distinct mean annual precipitation and temperature. Phenological data show some differences between the varieties regarding months with the highest number of flowering and fruiting records. In general, M. principis var. macrocalyx presents larger flower and pollen characters, and smaller fruit characters compared to the typical variety. Based on these findings, we elevate the variety to the status of species, as the new combination Metternichia macrocalyx. Following IUCN guidelines, both taxa are here preliminarily considered endangered (EN).

Knowledge on biodiversity is fundamental for conservation strategies. The Brazilian Pampa region, located in subtropical southern Brazil, is neglected in terms of conservation, and knowledge of its biodiversity is fragmented. We aim to answer the question: how many, and which, species occur in the Brazilian Pampa? In a collaborative effort, we built species lists for plants, animals, bacteria, and fungi that occur in the Brazilian Pampa. We included information on distribution patterns, main habitat types, and conservation status. Our study resulted in referenced lists totaling 12,503 species (12,854 taxa, when considering infraspecific taxonomic categories [or units]). Vascular plants amount to 3,642 species (including 165 Pteridophytes), while algae have 2,046 species (2,378 taxa) and bryophytes 316 species (318 taxa). Fungi (incl. lichenized fungi) contains 1,141 species (1,144 taxa). Animals total 5,358 species (5,372 taxa). Among the latter, vertebrates comprise 1,136 species, while invertebrates are represented by 4,222 species. Our data indicate that, according to current knowledge, the Pampa holds approximately 9% of the Brazilian biodiversity in an area of little more than 2% of Brazil’s total land. The proportion of species restricted to the Brazilian Pampa is low (with few groups as exceptions), as it is part of a larger grassland ecoregion and in a transitional climatic setting. Our study yielded considerably higher species numbers than previously known for many species groups; for some, it provides the first published compilation. Further efforts are needed to increase knowledge in the Pampa and other regions of Brazil. Considering the strategic importance of biodiversity and its conservation, appropriate government policies are needed to fund studies on biodiversity, create accessible and constantly updated biodiversity databases, and consider biodiversity in school curricula and other outreach activities.

In times of unprecedented climate change, ecological restoration efforts have a strong focus on forests for the purpose of carbon sequestration. Grasslands, in contrast, remain relatively neglected in global restoration policies. Concurrently, we are in the midst of a biodiversity crisis—it is estimated that 1 million species are globally threatened with extinction. Here, we present analyses from central Europe and southern Brazil that show that the majority of our endangered plant species are in fact found in open ecosystems. Using Germany as an example, we show that we could reduce plant extinction risk by up to 82% if we restore open, grassy ecosystems. This also holds true for southern Brazil, where grassland species constitute the single largest share of endangered species, but where grassy ecosystems continue to be systematically neglected by restoration policies. We further expand on our biodiversity argument to include the role that grassland restoration can play in mitigating climate change. We posit that ramping up grassland restoration efforts may not only be our best bet to bend the curve of biodiversity loss, but it will also make a critical contribution to the resilience of ecosystems in the dynamic decades to come. It is time for grassland restoration to receive higher priority in global restoration efforts and policy.

Solanaceae comprises many species complexes, taxonomically challenging lineages that require specialized effort to be reliably delimited, and thus develop a reasoned hypothesis at the species level. To obtain an overview of aspects that permeate species complexes studies in Solanaceae, we collected and summarized details of selected works, resulting in 83 published articles comprising nine genera. Solanum, the most studied genus, spans all explored biogeographic realms, characterized by taxonomic complexity related to its long history of domestication. Capsicum is a unique case due to the adoption of complexes as an indicator of gene pool, while Petunia can potentially serve as a model for the use of species complexes to improve evolutionary knowledge given their phylogeographic studies. The Neotropical region concentrates the majority of research and presents the highest number of genera studied. Morphometrics is the main applied approach probably due to its low cost, followed by population genetics, reproductive biology, phylogeny, and others. Most studies do not present taxonomic decisions or apply integrated methods. We encourage studies with some neglected genera that may have hidden species complexes; a major effort to resolve the Solanum nigrum complex; and the use of effective, less applied fields of study such as ecology and palynology.

Aims: To identify environmental and anthropogenic drivers of alpha‐ and beta‐diversity for native and alien plant species.Location: Río de la Plata grasslands, South America (Argentina, Brazil and Uruguay; 27.3–39.1°S, 50.1–66.5°W).Methods: We assembled a data set of 597 vegetation plots distributed across the Río de la Plata grasslands. To assess the drivers of native and alien alpha‐diversity (species richness), we performed a generalized least‐squares regression using environmental and anthropogenic predictors. We evaluated differences in beta‐diversity using Simpson's pairwise dissimilarity between pairs of plots and used multiple regression on distance matrixes to investigate environmental and anthropogenic drivers on compositional dissimilarity for both native and alien plant species.Results: Native species richness was higher in sites with less demanding environmental conditions, such as lower precipitation seasonality and soils with higher cation exchange capacity. Numbers of alien species were positively related to soil pH, cropland density and road density and negatively to precipitation seasonality, mean temperatures and soil cation exchange capacity. The compositional dissimilarity was similar for native and alien species assemblages (mean ± SD: 0.64 ± 0.16 and 0.64 ± 0.35 respectively). Areas having similar climates and being geographically close shared more taxonomically similar assemblages, for both native and alien assemblages, while soil had disparate effects. Compositional dissimilarity of alien plants decreased with increasing road density.Conclusions: Our results highlight a grassland ecosystem where native species richness is still shaped only by environmental factors, but both sets of factors influence its composition. On the other hand, alien plants carry a strong signal of both environmental and human factors. As time progresses the number of alien species tend to increase, eroding the patterns of native biodiversity. To avoid this, efforts should be made to reduce road encroachment and the conversion of natural grasslands into croplands.