Bráulio Almeida Santos

Although street trees may ameliorate the negative impacts of urbanization on biodiversity and improve cities' sustainability standards, they have been globally used with poor ecological criteria. In many cities, there is a notable lack of standardized assessments of street afforestation, particularly those outside major urban centers. Here we evaluate the distribution, richness, and species composition of street trees in 10 semi‐arid Brazilian cities, analyzing the proportion of native and non‐native species and the potential of these urban areas to support biodiversity. In each city, we sampled four 300‐m linear transects of woody vegetation along public roads and conducted a satellite‐based supervised classification to examine the relationship between species richness and the percentage of local impervious surface. A total of 1381 trees of 69 species were identified. About 80% of the individuals and 52% of the species were non‐native. More concerning, approximately 60% of the individuals belonged to exotic invasive species; the Indian Neem alone, Azadirachta indica , accounted for 700 individuals. As expected, the increase in impervious surface cover negatively affected the native species richness. Five cities were classified as antagonistic for biodiversity due to the high proportion and dominance of non‐native species. These findings reveal a concerning bias towards exotic invasive tree species in the studied Brazilian cities, potentially causing negative effects on the remaining urban biota. We strongly recommend that street afforestation strategies remove the invasive species from their portfolio, reduce the use of exotic non‐invasive ones, and increase the adoption of native trees as much as possible.

Ant‐mediated seed dispersal is a key ecological service in seasonally dry tropical forests, contributing to plant regeneration and ecosystem resilience. In human‐modified landscapes, however, the quality and quantity of these interactions may be altered by local and landscape‐scale environmental factors. We investigated how soil properties and landscape aspects influence ant‐mediated seed dispersal in rainfed croplands and natural vegetation remnants within the Caatinga, a dry forest biome in northeastern Brazil. Seed removal and seed cleaning were measured using standardized bait experiments, and interacting ant species were classified by dispersal quality based on body size. Habitat, soil and landscape context jointly shaped ant‐mediated seed dispersal. Croplands supported more high‐quality interactions, while soil pH and sand content influenced interaction quality. At the landscape scale, water availability and fragmentation reduced seed dispersal components, whereas land‐use heterogeneity increased total interactions, likely through small‐bodied, disturbance‐tolerant ants. Distinct ant groups provided different seed dispersal components (cleaning vs removal), shaped by habitat and landscape factors. While plant recruitment and long‐term recovery were not directly assessed, our findings indicate that small‐scale rainfed agricultural landscapes can support functional components of ant‐mediated seed dispersal with potential relevance for dry forest regeneration.

Understanding the drivers of plant community stability is crucial for predicting ecosystem responses to extreme drought events. In grasslands, drought resistance supports the maintenance of key functions such as above‐ground primary productivity, making the identification of resistance drivers essential to guide management under climate change. Proposed factors contributing to grassland stability include multiple diversity facets, functional traits and long‐term climate, but most assessments focus on temporal invariability under historical disturbance regimes, leaving mechanisms of extreme drought resistance and their variation across climatic contexts relatively underexplored. Here, we analysed data from 54 grassland sites of the International Drought Experiment to examine the resistance of above‐ground net primary productivity to a short‐term (i.e. 1 year) extreme drought. We investigated the relative importance and joint influence of functional composition (i.e. community‐weighted means of leaf and root traits), plant diversity facets (taxonomic, functional and phylogenetic) and climate (aridity and rainfall variability) on drought resistance. We used structural equation models to disentangle direct, indirect, and moderating pathways linking these drivers to drought resistance. Long‐term aridity appeared as one of the most important drivers of grassland resistance to drought, with more arid sites showing lower resistance. Moreover, aridity impacted resistance through indirect effects by shaping functional composition and plant diversity, and by moderating the influence of plant diversity and functional composition. Functional composition related to dehydration avoidance and dehydration tolerance was also positively associated with resistance, while diversity had a weaker relationship with resistance, mostly through functional and phylogenetic facets. Interannual rainfall variability also influenced resistance, with different effects in more arid versus humid and less arid sites. Synthesis . Widely studied stability drivers such as plant diversity and functional composition have only partial explanatory power for short‐term drought resistance of above‐ground productivity in grasslands at a global scale. The abiotic context, particularly long‐term aridity, is crucial for understanding ecosystem responses to rainfall variation and can improve predictive models for advancing the study of ecosystem resistance to drought. Along with management practices that target high species diversity or specific traits, restoration and conservation practices should support vulnerable sites experiencing high aridity

Increased climate variability is expected to intensify short-term drought events. Plants have evolved stress tolerance strategies involving trade-offs in resource conservation, mycorrhizal collaboration and plant size, yet how these strategies promote drought resistance across different herbaceous plant groups remains unknown. Leveraging 63 globally distributed grassland and shrubland sites from the International Drought Experiment, we identified plant traits linked to drought resistance in 661 populations of 421 species after 1 year of extreme drought. We assessed how traits, site precipitation and drought severity affected cover change across growth forms and lifespans, and how trait–environment interactions influenced drought resistance. Across all species, leaf N (an acquisitive trait) was associated with drought resistance, whereas in forbs, drought resistance was also associated with a conservative root trait and plant size. In addition, interactions among traits mediated drought resistance; root traits predicted performance only in concert with other traits. Environmental variables influenced trait effects on drought resistance, notably for annuals in wetter sites, suggesting that drought-escape strategies in annuals may be advantageous only under mild stress. Our study highlights variability in traits that predict drought resistance across herbaceous plant groups, emphasizing the importance of species context, environmental stress and the selection of traits in research and management.

As droughts become longer and more intense, impacts on terrestrial primary productivity are expected to increase progressively. Yet, some ecosystems appear to acclimate to multiyear drought, with constant or diminishing reductions in productivity as drought duration increases. We quantified the combined effects of drought duration and intensity on aboveground productivity in 74 grasslands and shrublands distributed globally. Ecosystem acclimation with multiyear drought was observed overall, except when droughts were extreme (i.e., ≤1-in-100-year likelihood of occurrence). Productivity losses after four consecutive years of extreme drought increased by ~2.5-fold compared with those of the first year. These results portend a foundational shift in ecosystem behavior if drought duration and intensity increase, from maintenance of reduced functioning over time to progressive and profound losses of productivity when droughts are extreme.

Habitat fragmentation generally reduces biodiversity at the patch scale (α diversity)¹. However, there is ongoing debate about whether such negative effects can be alleviated at the landscape scale (γ diversity) if among-patch diversity (β diversity) increases as a result of fragmentation^2,3,4,5,6. This controversial view has not been rigorously tested. Here we use a dataset of 4,006 taxa across 37 studies from 6 continents to test the effects of fragmentation on biodiversity across scales by explicitly comparing continuous and fragmented landscapes. We find that fragmented landscapes consistently have both lower α diversity and lower γ diversity. Although fragmented landscapes did tend to have higher β diversity, this did not translate into higher γ diversity. Our findings refute claims that habitat fragmentation can increase biodiversity at landscape scales, and emphasize the need to restore habitat and increase connectivity to minimize biodiversity loss at ever-increasing scales.