University of Maryland Center for Environmental Science

Many degraded streams in the Chesapeake Bay watershed have been structurally modified over the last two decades in an effort to reduce nutrient and sediment loads from urban catchments and contribute to the pollutant reduction goals of the Chesapeake Bay Total Maximum Daily Load (TMDL). The step-pool streamwater conveyance (SPSC) is a stream restoration design that has been extensively implemented in Maryland and the District of Columbia. In the summer of 2019, an SPSC was constructed in a degraded 800 m stream reach on the University of Maryland campus (i.e., Campus Creek). Precipitation, baseflow and stormflow runoff, and nutrient (nitrogen and phosphorus) and total suspended solid (TSS) concentrations were measured throughout pre- and post-restoration periods (~2 and 5 years, respectively) to determine the extent to which the SPSC structure reduced pollutant loads. A comparison of pre- (2018) versus post-restoration (2020) years with similar total annual rainfall volumes indicates that total annual runoff was 13% lower in the post-restoration period. Area yields of total nitrogen (TN), total phosphorus (TP) and TSS were 33, 39 and 59% lower, respectively, in the same pre- versus post-restoration comparison.

Introduction Artificial reefs (ARs) have been widely used to provide ecological and fisheries benefits. Quantitative evaluation of how the numbers and spatial layout of ARs affect fish responses can provide critical insights for management. Methods We used survey data from an area in the Bohai Strait (China) that has ARs deployed and developed species distribution models (SDMs) predicting the occurrence probabilities of three commercially important species ( Charybdis japonica , Sebastes schlegelii , and Hexagrammos otakii ) and one undesirable focal species ( Asterias amurensis and Asterina pectinifera combined). Three versions of SDMs were developed: a Best-fit model based on survey data, and two modified versions (Intermediate and Extreme), that incorporated increasing levels of AR-to-AR interactions, reflecting competitive and connectivity effects. A 24×24 grid with 50-m cells was populated with bottom habitat type (mud, gravel, rubble, boulder, or AR) and key environmental variables affecting occurrence probabilities. Using simulations of 10,000 randomly-generated spatial layouts of added ARs (bottom type switched to AR), we compared predicted occurrence probabilities from the Best-fit, Intermediate, and Extreme SDMs when 5, 10, 25, and 50 ARs were added to the existing ARs. Performance was evaluated using the predicted species-specific occurrence probabilities, with occurrence of the undesirable species treated inversely (i.e., lower occurrence probability indicated higher performance). Results Increasing AR numbers increased the percentage of grid cells supporting good habitat, but saturation and interference effects caused similar values for 25-50 ARs for several species, while reducing variation across spatial layouts. The three desirable species showed similar patterns with the representative layouts categorized into good and bad performing: increasing spread of good ARs on the grid with number of ARs deployed, shift of good ARs from upper to lower triangle, and an increasingly bad-performing central area with 50 ARs. The spatial overlap between high-performing cells for desirable species and elevated occurrence of undesirable Sea star illustrated an inherent trade-off that should be considered in management objectives. Discussion We conclude with a discussion of the need for AR layout-specific evaluation, consideration of AR interaction strength, broader applicability to other systems, potential pathways to expand the analysis (e.g., add hydrodynamic models), and caveats and recommendations for further development.

Abstract We announce updates to the aims and scope of Earth's Future that introduce three Thematic Areas: Climate Impacts, Communities and Resilience, and Sustainable Resource Systems. These additions provide focal points for community building and editorial leadership within the journal's broad, transdisciplinary mission. We describe the motivation for these changes, outline each thematic area, and reaffirm that Earth's Future remains open to submissions across the full scope of Anthropocene science.

Understanding how land use and land cover changes (LULCCs) affect ecosystem services (ES) is essential for guiding sustainable management strategies in protected areas (PAs), particularly in small island contexts where ecological processes, historical land uses and socio-economic dynamics are tightly interwoven. This study explores the medium-term dynamics of ES supply using LULCCs as a spatial indicator on the island of Asinara (Italy). Spatially modelled results show that the transition from agricultural and semi-natural uses to uncultivated areas, driven by land abandonment and soft nature-restoration actions, has reshaped the balance between provisioning, regulating and cultural services, generating reflections on opportunities and land management challenges. These outcomes require careful contextualization to reflect underlying ecological processes and land capabilities, highlighting the need for governance frameworks oriented towards conservation-driven landscape management rather than passive rewilding, especially in landscapes long shaped by human activities. More generally, sustainability in PAs is not an automatic outcome of protection or abandonment, but a contingent, spatially differentiated and governed process, in which indicators and maps serve to guide decisions, not to certify their success.

Karenia brevis regularly forms harmful blooms along the West Florida Shelf that negatively affect marine and terrestrial organisms through toxin production. These blooms impose economic and environmental hardship, driving the need for research to understand the factors influencing their dynamics and to mitigate their impacts. A mostly unresolved issue is the potential role of viruses in bloom termination. We conducted an experiment incubating K. brevis cultures with size-fractionated bloom water samples. Flow cytometry revealed giant virus-like populations (VLPs) in replicate cultures with <1 μm-filtered and <0.2 μm-filtered bloom water. The VLPs’ abundance was paralleled by declines in photoefficiency and culture lysis. Metagenomic analyses of the lysates revealed 11 giant virus genomes (35%–100% complete) representing 7 viral operational taxonomic units (vOTUs) within the order Imitervirales (Nucleocytoviricota). Ten of these vOTUs were more abundant in the incubations with <0.2 μm-filtered bloom water, coinciding with the absence or low abundance of algicidal bacteria. The vOTUs and K. brevis cell abundances showed a positive correlation at a coastal site during bloom and nonbloom periods. The most apparent association was to vOTU6, which may owe its competitive advantage to the presence of the auxiliary metabolic genes bacteriorhodopsin, carbonic anhydrase, and dinoflagellate viral nucleoprotein. The metagenomes also contained polinton-like virus (PLV) genomes. Since many PLVs are hypothesized to depend on co-infection with Nucleocytoviricota viruses for their propagation, our results suggest complex viral interactions within K. brevis blooms. Future research to elucidate virus–bacteria–K. brevis interaction mechanisms may be key to understanding bloom dynamics and developing management tools.

Oyster aquaculture and restoration in the Chesapeake Bay are vital, yet hatcheries frequently struggle with inconsistent larval growth and sudden mass mortality events. Unpredictable disruptions in larval production cause large economic losses, represent a perceived risk to growers, and impede industry expansion. To better understand associations between production yield and its potential predictors, we applied machine learning (random forest, and neural network) and statistical (generalized additive model) models to a comprehensive dataset of environmental, water quality, and operational parameters from a Maryland oyster hatchery, aiming to identify key yield predictors and develop a robust forecasting tool. We used recursive Boruta algorithm for variable selection, pinpointing critical predictors, and employed cross-validation to fine-tune model settings. Shapley value analysis offered crucial insights into model interpretations, highlighting week number, Normalized Difference Vegetation Index, salinity, turbidity, and fecundity as primary drivers of yield variability. For low-yield cases, salinity-related variables were particularly important. Our findings provide an early warning system for potential production downturns, empowering hatchery operators to make data-driven decisions for optimizing water conditions, feeding schedules, and broodstock management. By boosting predictability and efficiency, this research directly supports economic stability of the oyster industry and ecological health of the Chesapeake Bay.

ABSTRACT This article provides two examples (an external and an internal evaluation with the NSF INCLUDES SEAS Islands Alliance) of a people‐centered approach to evaluation. We review how we came to our people‐centered approaches and how we used that approach in this particular context. First, we discuss an external evaluation of the Alliance examining relationships among Alliance members and with their community partners, and then we offer a discussion of the internal evaluation strategy used to better understand relationships within the Alliance. There were some differences, as well as many commonalities, in the way we, as evaluators, approached building authentic relationships that valued the context and the Alliance members. We contend that, regardless of an evaluation's goals, there are ways to incorporate people‐centered evaluation approaches into evaluation work .

Background Recent studies looking to advance knowledge of fire-effects on trees have used both heated water baths and experimental laboratory fires to apply heat to plant tissues. Aims We assessed whether heated water baths and experimental laboratory fires caused xylem cell wall deformation and increased vulnerability to embolism. Methods Using Pinus ponderosa and Pinus monticola saplings, we measured impacts using both heated water bath treatments and experimental laboratory fires, with parameters elucidated by prior studies that observed effects associated with lethal outcomes. Key results We show that increased vulnerability to embolism only occurred in one of the species tested when using the heated water baths and did not occur in either species when using the laboratory fire treatments. Neither treatment caused xylem cell deformations. Conclusions Heated water baths may generate misleading results in some species and therefore should be used with caution when researching effects due to wildland fires. Implications Future studies should assess the potential of other common fire dynamics proxy methods.