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Abstract Marine ecosystems worldwide are increasingly degraded by upstream land use activities, compounding climate change impacts. However, empirically quantifying causal land-sea linkages remains challenging. Using remote sensing data (1987-2019) and four causal inference methods, here we developed an empirical and scalable framework to estimate how land use affects coastal turbidity across spatial scales in southern Costa Rica. We found that riparian natural vegetation (15 m buffer) significantly reduced gulf turbidity up to 800 m offshore, which overlaps with coral reefs and seagrass habitats. In contrast, pasture and gravel roads increased coastal turbidity. Effects were greatest for rivers that are short, steep, or have low discharge. Watershed-scale land uses showed no significant effects. We provide a replicable, scalable framework to identify causal pathways from land to sea, particularly valuable in data-limited regions. Riparian conservation and restoration could serve as effective strategies to align human land use needs with terrestrial, freshwater, and marine conservation. 

Abstract Microbial communities in streams occupy diverse habitats and drive nutrient cycling and organic matter dynamics. However, streams are impacted by climate change and human activities, with many small streams only flowing intermittently. Spatial patterns in microbial activity in these systems are poorly understood, especially in co-occurring habitats. This study investigated how microbial activity varied across four different habitats in an intermittent stream network. The activity of enzymes involved in organic matter decomposition (β-glucosidase, phenol oxidase, peroxidase) and organic phosphorus (phosphatase) and nitrogen (N-acetylglucosaminidase) mineralization was determined for water, epilithic biofilm, leaf litter and sediment, collected from 48 locations across 1.3 km²in Kings Creek, Kansas, USA. Microbial activity varied in magnitude and spatial distribution across the stream network, with spatial patterns differing by enzyme and habitat. Activities of β-glucosidase, phosphatase, and N-acetylglucosaminidase were correlated across all habitats, and positively correlated with phenol oxidase and peroxidase activity in leaf litter and sediment. Spatial patterns in activity were influenced by several factors, with moisture content, drainage area and topographic wetness index showing contrasting effects across habitats. Enzyme stoichiometry suggested that microbial communities in water and sediment were mainly co-limited by carbon and phosphorus, while those in biofilms were primarily nitrogen-limited, and those in leaf litter were either limited by nitrogen or co-limited by carbon and phosphorus. This study shows pronounced spatial heterogeneity in microbial activity within a small catchment, emphasizing how interactions between reach-scale and watershed-scale factors regulate organic matter and water availability, thereby shaping microbial function. 

Abstract The dual challenges of blue food security and ocean acidification (OA) have become increasingly urgent concerns for global sustainability. Blue foods, which provide key nutrients, are threatened by OA, posing risks to biodiversity, fisheries, and the livelihoods of communities that depend on them. The pressure of OA highlights the urgency of addressing blue food security through the lens of OA. Understanding the governance landscape that shapes responses is crucial, yet existing literature has largely considered the OA and blue food security regimes separately. This paper analyzes whether and how the international governance of OA and blue food security intersect by mapping their regime complexes. The central research question investigates how international regimes interact in governing this nexus. The analysis finds that the two regime complexes overlap in many areas, including fisheries/marine resources and climate change. Although many actors and instruments mention both topics, significant governance fragmentation persists. Case studies on the Food and Agriculture Organization (FAO) and the United Nations Framework Convention on Climate Change (UNFCCC) reveal that neither institution provides a comprehensive framework for governing the nexus of OA and blue food security resilience. The FAO lacks an explicit mandate for OA governance. If mentioned, OA is relegated to a list of stressors. The UNFCCC addresses OA only indirectly through CO₂mitigation efforts, and its instruments, while referencing food production, generally do not link it explicitly to OA. This results in fragmented authority, unclear responsibility, and limited integration across policy domains. Furthermore, a discrepancy exists where blue food security is recognized as a topic of legal and political urgency, while OA often only gains scientific attention. We conclude that further joint integration of OA and blue food security in legal and policy frameworks is necessary to enhance coherence and coordination across these regimes. 

Abstract Fungi comprise millions of species that play numerous varied roles in Earth’s natural and managed ecosystems, engaging in a multitude of positive and negative ecological interactions. The dispersal ecology of fungi is central to global biodiversity patterns, maintenance of terrestrial and aquatic ecosystem functions, and tracking human disease and plant pathogen outbreaks. Mycologists have been studying dispersal mechanisms for over a hundred years, but new technology as well as interdisciplinary approaches have reinvigorated research in the field. Here we present 100 research questions in fungal dispersal organized into ten themes: 1) dispersal traits and mechanisms, 2) effects of phenology and lifestyle, 3) spore liberation and transport mechanisms, 4) colonization and establishment, 5) ecosystem-level consequences of dispersal, 6) dispersal in symbiotic and host-associated fungi, 7) dispersal in anthropogenic and changing environments, 8) evolution and tradeoffs in dispersal, 9) role of dispersal in invasion and disease spread, and 10) methodology and techniques. The questions reflect a diversity of new research avenues from fundamental fungal biology to applied ecosystem management and conservation across spatial and temporal scales. They potentially enable integrating fungi and their unique life-history traits and dispersal strategies into existing dispersal frameworks developed around plant and animal systems. We aim to invigorate fungal dispersal research, sparking conversations and providing a focused agenda to widen the tent by illuminating unanswered questions and new research avenues in ecology and evolutionary biology. 

Abstract Increases in area of extent, severity, and frequency of wildfires across the western United States are presenting challenges to socio‐ecological systems, including shifts to alternative ecological states, loss of homes, and compromising human health. Wildfire suppression operations, such as constructing hand lines to limit the spread of fire, are an important part of wildland fire management, particularly in the wildland urban interface. Like other attributes of wildland fire activity and effects, suppression strategies and their effectiveness vary with ecological, topographic, climatological, and sociopolitical factors. However, there has been little research that examines the efficacy of suppression operations, specifically as they relate to forest composition. Here, we ask about the effectiveness of fire line construction based on adjacent stand composition. Specifically, we ask: (1) Are wildfire suppression lines preferentially constructed in stands with specific tree species? (2) How does species identity influence the probability that suppression lines hold when also considering differences in topography, climate, and extreme fire weather? We anticipated that suppression operations will be biased towards—and more effective in—stands with quaking aspen because they are often associated with less extreme fire behavior than many conifer species. We conducted our study in the southern Rocky Mountain ecoregion using fires (n = 36) that burned during 2019–2023 and included records of fire suppression operations (n = 4295). We used nonparametric statistical models to elucidate biases in the construction of fire lines and the effects of stand composition. We found quaking aspen was the least common tree species to be within fire footprints, yet fire lines were placed near quaking aspen 1.68–5.30 times more than commonly co‐occurring tree species. Fire growth, independent of stand composition, was the most important predictor for whether fire suppression lines were likely to hold but the percentage of fire lines that held differed between fires >40,500 ha and smaller events (65% vs. 82%, respectively). This research suggests that wildland firefighters preferentially located fire lines near aspen stands, perhaps due to the long‐held notion that aspen stands are less flammable. However, during extreme burning conditions fire lines are unlikely to hold regardless of stand composition. 

Abstract Drylands cover 41% of Earth’s land surface, support 36% of the global population and contribute 60% of global food production. Despite these ecosystems’ importance and high vulnerability to droughts and heatwaves, drylands remain some of the most understudied systems on Earth. Monitoring drylands is challenging due to their complex ecosystem structure of visible soil mixed with diverse plant species that respond rapidly to weather and climate. In 2023 and 2024, a NASA scoping study was conducted for a proposed dryland terrestrial ecology field campaign called Adaptation and Response in Drylands (ARID). Thereafter, the NASA ARID scoping team submitted their campaign proposal to NASA Headquarters, providing a study design for how field, aircraft and satellite measurements, as well as modeling, could address the most critical fundamental and applied science questions in drylands. The extensive strategic vision was created by and for the drylands research community, including remote sensors, modelers, experimentalists and ecologists from across the world, and the overall approach can be further utilized and altered for different uses and data information needs. Here, we summarize the final ARID research agenda, including its main objectives, field campaign strategy, data end-user support strategy, and U.S. and global community engagement. 

Summary Predicting shifts in species composition with global change remains challenging, but plant functional traits provide a key link to scale from plant to community and ecosystem levels. The extent to which functional trait shifts may mediate ecosystem response to climate change remains a critical question.We ran point‐scale Community Land Model (CLM) simulations with site‐specific functional trait and phenology observations to represent alpine tundra growth strategies. We validated our results with site observations and compared parameterized results to those using the default parameterization. We then quantified the relative contribution of plant functional trait shifts vs climate change scenarios (and the resulting phenological shifts) to uncertainty in future tundra ecosystem productivity outcomes.We found that using community‐specific functional traits and phenology observations significantly improved productivity estimates compared with overestimates in a default simulation. Uncertainty in potential plant trait shifts often had a larger effect on ecosystem productivity responses than uncertainty in the forced response from different climate change scenarios.These findings highlight the key role of functional traits in shaping vegetation responses to climate change and the value of incorporating site‐level measurements into land models to more accurately forecast climate change impacts on ecosystem function. 

Abstract Sea surface height observations provided by satellite altimetry since 1993 show a rising rate (3.4 mm yr⁻¹) for global mean sea level. While on average, sea level has risen 10 cm over the last 30 years, there is considerable regional variation in the sea level change. Through this work, we predict sea level trends 30 years into the future at a 2° spatial resolution and investigate the future patterns of the sea level change. We show the potential of machine learning (ML) in this challenging application of long-term sea level forecasting over the global ocean. Our approach incorporates sea level data from both altimeter observations and climate model simulations. We develop a supervised learning framework using fully connected neural networks (FCNNs) that can predict the sea level trend based on climate model projections. Alongside this, our method provides uncertainty estimates associated with the ML prediction. We also show the effectiveness of partitioning our spatial dataset and learning a dedicated ML model for each segmented region. We compare two partitioning strategies: one achieved using domain knowledge and the other employing spectral clustering. Our results demonstrate that segmenting the spatial dataset with spectral clustering improves the ML predictions. Significance StatementLong-term projections are needed to help coastal communities adapt to sea level rise. Forecasting multidecadal sea level change is a complex problem. In this paper, we show the promise of machine learning in producing such forecasts 30 years in advance and over the global ocean. Continued improvements in prediction skills that build on this work will be vital in sea level rise adaptation efforts. 

Abstract Coastal ecosystems such as mangroves, salt marshes, and seagrasses sequester large amounts of carbon per unit area due to their high productivity and sediment accumulation rates. However, only a handful of studies have examined carbon sequestration in coastal dunes, which are shaped by biophysical feedback between aeolian sediment transport and burial-tolerant vegetation. The goal of this study was to measure carbon storage and identify the factors that influence its variability along the foredunes of the US Outer Banks barrier islands of North Carolina. Specifically, differences in carbon stocks (above- and belowground biomass and sand), dune grass abundance, and sand supply were measured among islands, cross-shore dune profile locations, and dune grass species. Carbon varied among aboveground grass biomass (0.1 ± 0.1 kg C m⁻²), belowground grass biomass (1.1 ± 1.6 kg C m⁻³), and sand (0.9 ± 0.6 kg C m⁻³), with the largest amount in belowground grass stocks. Aboveground grass carbon stocks were comparable to those in eelgrass beds and salt marshes on a per-area basis, while sediment carbon values in our study system were lower than those in other coastal systems, including other dune locations. Additionally, sand carbon density was positively related to patterns in dune sand supply and grass abundance, reflecting a self-reinforcing vegetation-sediment feedback at both high and low sand accumulation rates. 

Abstract Ecological disturbance regimes are shifting and leaving behind novel legacies, like the remnant structures of dead foundation species, which have poorly known impacts on ecosystem resilience. We explored how dead coral skeletons produced by marine heatwaves—material legacies of increasingly common disturbances on coral reefs—influence spatial competition between corals and macroalgae, focusing on whether removing dead branching skeletons stimulates recovery of coral after disturbance. Following a marine heatwave, we removed dead skeletons from reef patches and then used underwater photogrammetry and AI‐powered image analysis to quantify trajectories of coral and macroalgae. After four years, removal of dead skeletons resulted in 1.6 times more live coral remaining and reduced development of macroalgae by half, relative to patches where skeletons were left intact. Dead skeletons acted as an alternate substrate type that facilitated macroalgae development, and greater macroalgal abundance caused steeper declines in live coral. Lastly, removal of dead skeletons led to five times greater densities of coral recruits on stable (primary) reef substrate than on comparatively unstable branching coral skeletons. Our findings identify a promising avenue to manage for coral resilience (on reefs where carbonate budgets are not in a deficit) and reveal how material legacies of changing disturbance regimes can alter physical environments to sway the outcomes of spatial competition.