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Understanding the processes that are driving variation of natural microbial communities across space or time is a major challenge for ecologists. Environmental conditions strongly shape the metabolic function of microbial communities; however, other processes such as biotic interactions, random demographic drift or dispersal limitation may also influence community dynamics. The relative importance of these processes and their effects on community function remain largely unknown. To address this uncertainty, here we examined bacterial and archaeal communities in replicate ‘miniature’ aquatic ecosystems contained within the foliage of wild bromeliads. We used marker gene sequencing to infer the taxonomic composition within nine metabolic functional groups, and shotgun environmental DNA sequencing to estimate the relative abundances of these groups. We found that all of the bromeliads exhibited remarkably similar functional community structures, but that the taxonomic composition within individual functional groups was highly variable. Furthermore, using statistical analyses, we found that non-neutral processes, including environmental filtering and potentially biotic interactions, at least partly shaped the composition within functional groups and were more important than spatial dispersal limitation and demographic drift. Hence both the functional structure and taxonomic composition within functional groups of natural microbial communities may be shaped by non-neutral and roughly separate processes.Microbial communities in the foliage of wild bromeliads exhibit remarkably stable functional community structure despite large variation in taxonomic composition, indicating that non-neutral processes drive changes in community composition.

Transformative governance is key to addressing the global environmental crisis. We explore how transformative governance of complex biodiversity–climate–society interactions can be achieved, drawing on the first joint report between the Intergovernmental Panel on Climate Change and the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services to reflect on the current opportunities, barriers, and challenges for transformative governance. We identify principles for transformative governance under a biodiversity–climate–society nexus frame using four case studies: forest ecosystems, marine ecosystems, urban environments, and the Arctic. The principles are focused on creating conditions to build multifunctional interventions, integration, and innovation across scales; coalitions of support; equitable approaches; and positive social tipping dynamics. We posit that building on such transformative governance principles is not only possible but essential to effectively keep climate change within the desired 1.5 degrees Celsius global mean temperature increase, halt the ongoing accelerated decline of global biodiversity, and promote human well-being.

Climate change will substantially increase extreme rainfall events, especially in the Tropics, enhancing flood risks. Such imminent risks require climate adaptation strategies to endure extreme rainfall and increase drainage systems. Here, we evaluate the potential of nature-based solutions by using an ecosystem service modeling approach, evaluating the impact of extreme rainfall events on flood risks in a large urban area and with a real-world land recovery plan. We evaluate the cost-effectiveness of four different land recovery scenarios and associated co-benefits, based on a gradient increase in area recovered and cost of implementation. Although the scenarios reveal increasing flood risk reduction and co-benefits along with greater proportion of land recovery, the most cost-effective scenario was the one with an intermediate land recovery where 30% of the study area would be reforested. We emphasize the striking benefits of nature-based solutions for flood risk reduction in cities, considering landscape scale and stakeholders’ needs.

Climate change and biodiversity loss are expected to simultaneously affect ecosystems, however research on how each driver mediates the effect of the other has been limited in scope. The multiple stressor framework emphasizes non-additive effects, but biodiversity may also buffer the effects of climate change, and climate change may alter which mechanisms underlie biodiversity–function relationships. Here, we performed an experiment using tank bromeliad ecosystems to test the various ways that rainfall changes and litter diversity may jointly determine ecological processes. Litter diversity and rainfall changes interactively affected multiple functions, but how depends on the process measured. High litter diversity buffered the effects of altered rainfall on detritivore communities, evidence of insurance against impacts of climate change. Altered rainfall affected the mechanisms by which litter diversity influenced decomposition, reducing the importance of complementary attributes of species (complementarity effects), and resulting in an increasing dependence on the maintenance of specific species (dominance effects). Finally, altered rainfall conditions prevented litter diversity from fueling methanogenesis, because such changes in rainfall reduced microbial activity by 58%. Together, these results demonstrate that the effects of climate change and biodiversity loss on ecosystems cannot be understood in isolation and interactions between these stressors can be multifaceted.

Current land-use and climate change patterns lead to disruption in ecosystem services provisioning essential for human well-being. Actions representing alternatives to business-as-usual trend can reduce negative impacts, but their effectiveness across ecosystems, climatic zones and scales is unclear. Here, we analyse how land recovery and climate action can counteract adverse effects of current trends on nature and safeguard provisioning of ecosystem services. Using a meta-analysis approach, we compiled 410 estimates of how land recovery or climate action may alter impacts expected from business-as-usual trends. We show that both alternatives can reduce negative effects on several nature indicators. The magnitude of the effects, however, is context-dependent, revealing their potential complementarity. Land recovery showed highest benefits in terrestrial and freshwater systems in temperate zones and mostly acts at subnational scale. Contrastingly, climate action is more important in coastal and oceanic systems and in tropical regions, where benefits are larger on a regional to global scale. Our results show that land recovery and climate action will be imperative to reduce risks that would be imposed on nature by business-as-usual trends otherwise. We conclude that a better evaluation of which contexts are best suited for certain actions is a first step towards securing nature and the ecosystem services necessary to guarantee human well-being and the fulfilment of the sustainability agenda.

Evaluating the factors that regulate bacterial growth in natural ecosystems is a major goal of modern microbial ecology. Phytotelm bromeliads have been used as model ecosystems in aquatic ecology as they provide many independent replicates in a small area and often encompass a wide range of limnological conditions. However, as far as we know, there has been no attempt to evaluate the main regulatory factors of bacterial growth in these aquatic ecosystems. Here, we used field surveys to evaluate the main bottom-up factors that regulate bacterial growth in the accumulated water of tank bromeliads. Bacterial production, water temperature, water color, chlorophyll-a, and nutrient concentrations were determined for 147 different tank bromeliads in two different samplings. Bromeliad position and the season of sampling were also noted. Bacterial production was explained by ion ammonium concentration and water temperature, but the total variance explained was low (r ² = 0.104). Sampling period and bromeliad position were included in additional models that gave empirical support for predicting bacterial production. Bromeliad water tanks are extremely variable aquatic ecosystems in space (among bromeliads) and time (environmental conditions can change within hours), and it is well known that bacterial production responds rapidly to environmental change. Therefore, we concluded that several factors could independently regulate bacterial growth in phytotelm bromeliads depending on the characteristics of each bromeliad, such as location, amount of detritus, and ambient nutrient concentrations. A clear bottom-up limitation pattern of bacterial production in tropical phytotelm bromeliads was not found.

Climate change alters ecosystems and their functioning, but biodiversity can buffer such changes. Previous syntheses suggest that biodiversity confers insurance; however, it is not clear whether this effect extends to climatic stressors. Here, we analyze 342 measures of the effects of biodiversity on stability in order to compare the response to climatic versus nonclimatic stressors. In general, the stabilizing effect of biodiversity is weaker for climatic than for nonclimatic stressors. We suggest that this reflects species pools being compiled at a small spatial scale for experiments testing climatic stressors. Some bias in the representation of biomes and stability metrics in biodiversity–climate studies may also distort the perceived effect of biodiversity on stability. We recommend that in future studies, researchers increase the spatial scale of experiments, manipulate multiple facets of biodiversity, simulate climate change in more realistic ways, and focus on underrepresented combinations of biomes and climatic stressors.

Non-technical summaryBrazil – one of the world's largest biocultural diversities – faces high rates of habitat loss, social inequality, and land conflicts impacting indigenous and local peoples. To challenge that, Brazilian sustainability science and education needs to be strengthened. We searched for elements in ongoing bottom-up sustainability social movements that can help serve that purpose. We found values, contents, and attitudes that, if incorporated into Brazilian sustainability science and education, can assist its transformative potential by reflecting local voices and critically engaging with (often-hegemonic) northern concepts.Technical summaryIn Brazil, a strong sustainability science and education is required to confront ‘glocal’ issues such as zoonotic pandemics and climate change, which are worsened by rampant ecosystem loss and social vulnerability. However, a largely disciplinary university system has been slow to meet these urgent needs. To address if and how dialogical processes with non-academics can prompt integration between distinct types of knowledge, we analyze four bottom-up sustainability initiatives that promote dialogues between science, the arts, religion, youth, and indigenous and local knowledge, and reflect on lessons learnt with movement organizers, scientists, and educators – the authors of this paper. Although sustainability science produced in dialogue with other forms of knowledge is still emerging in Brazil, we find that bottom-up initiatives outside academia can inspire science and education to approach sustainability as wholeness – a state of balance to be fulfilled when reached individually, collectively, and cosmically. We discuss how to approach a transdisciplinary and reflexive attitude in Brazilian sustainability science and education, and highlight its unique contribution to frontier topics in global sustainability debates.Social media summarySocial movements’ values, contents, and attitudes can inspire transformative Brazilian sustainability science and education.

Changes in the distribution of rainfall and the occurrence of extreme rain events will alter the size and persistence of aquatic ecosystems. Such alterations may affect the structure of local aquatic communities in terms of species composition, and by altering species interactions. In many aquatic ecosystems, leaf litter sustains detrital food webs and could regulate the responses of communities to changes in rainfall. Few empirical studies have focused on how rainfall changes will affect aquatic communities and none have evaluated if basal resource diversity can increase resistance to such rainfall effects. In this study, we used water-holding terrestrial bromeliads, a tropical aquatic ecosystem, to test how predicted rainfall changes and litter diversity may affect community composition and trophic interactions. We used structural equation modeling to investigate the combined effects of rainfall changes and litter diversity on trophic interactions. We demonstrated that changes in rainfall disrupted trophic relationships, even though there were only minor direct effects on species abundance, richness, and community composition. Litter diversity was not able to reduce the impact of changes in rainfall on trophic interactions. We suggest that changes in rainfall can alter the way in which species interact with each other, decreasing the linkages among trophic groups. Such reductions in biotic interactions under climate change will have critical consequences for the functioning of tropical aquatic ecosystems.

Brazil is a powerhouse in terms of water resources, which are instrumental to the country’s transition to sustainability. However, to realize this potential, substantial management and conservation hurdles must first be overcome. We propose a novel strategy for the use, management, and conservation of Brazilian water resources. Our approach recognizes the spatial heterogeneity of water abundance and is based on a multisectoral perspective, including energy, food, sanitation, and environmental conservation. The main recommendations are to adopt low-cost local and subnational solutions and to design policy mixes, both based on the logic of the nexus water-food-energy-ecosystem. We offer as examples programs that 1) increase cistern infrastructure in drylands, 2) use constructed wetlands to improve sewage treatment in small cities and vulnerable areas, 3) turn the focus of conservation to aquatic ecosystems, 4) stimulate the adoption of small hydrokinetic turbines for energy generation in sparsely populated river-abundant regions, such as the Amazon Region, 5) diversify the matrix of renewable energy sources by combining hydropower with biomass and wind energy generation, and 6) mixes policies by integrating multiple sectors to improve regulation, use and management of water resources, such as the Brazilian “Water for All” Program. By following these recommendations, Brazil would align itself with the goals established in international agreements and would turn its abundance of water resources into development opportunities.