9 Jun 2026

Considerations for Potential Use of an Agent-Based Model in a Petri Network Framework to Model Roost Tree Dynamics of Bats

Purpose: The US Army Corps of Engineers (USACE) is responsible for numerous projects that involve altering or removing wildlife habitat, including habitat of species listed as threatened, endangered, or sensitive (TES). Before initiating a project that may affect TES species, USACE must determine the project’s impact to these species. Understanding the degree of impact, both positive and negative, allows USACE to compare alternatives to reduce negative effects. Because of this, USACE planners need tools to provide accurate assessments of project impacts. Conservation efforts for bats have focused on protecting habitat, especially diurnal roosting trees. Roost trees serve not only as daytime shelter for bats but also for rearing pups until they are able to fly (Barbour and Davis 1969). Determining the impact of habitat change by empirically testing the response of bats to habitat modification has proved difficult because of the effects it may have on TES bats as well as its cost. Simulating the effects of habitat change using computer models provides an excellent data alternative for USACE planners. This technical note explains how agent-based models within a petri network framework can provide USACE planners with information on how habitat modification will affect bat presence or absence.

8 Jun 2026

Metabarcoding Stem Residue as a Novel Environmental DNA (eDNA) Tool to Identify Spread of Phragmites australis Biological Control Agents

Abstract: Detection and monitoring of biological control agents are critical for evaluating their establishment and spread yet remain challenging when species are cryptic, and densities are low. We assessed whether environmental DNA (eDNA) metabarcoding of stem residues could be used to detect and distinguish the stem-boring noctuid moths Archanara neurica and Lenisa geminipuncta, biological control agents of introduced Phragmites australis released in Ontario, Canada. Using 16S rDNA metabarcoding supplemented with newly generated reference sequences, we analyzed stem residue samples spanning a gradient of quality, including laboratory culture stems (in which agent larvae were present at the time of sampling), confirmed Canadian release sites, and degraded stems from un-managed Phragmites stands in western New York, USA. Target species were consistently detected in laboratory samples, where they comprised 76.7–100% (L. geminipuncta) and 79.2–100% (A. neurica) of Lepidoptera reads. At Canadian release sites, A. neurica was detected in 5 of 11 samples and L. geminipuncta in all 10 samples, with relative read abundances ranging from trace levels to > 90%. Among 27 damaged stems collected in the United States, A. neurica and L. geminipuncta DNA was detected in three samples at very low abundances (0.003–0.12% of total reads), representing the first molecular evidence consistent with trans-border dispersal of these agents. Although detections were rare and do not confirm population establishment, results demonstrate that stem-residue eDNA metabarcoding provides a sensitive, non-invasive tool for early detection and post-release monitoring of biological control agents for invasive plants.

8 Jun 2026

Evaluating Migratory Fish Passage at Partial Migration Barriers in a Social-Ecological Riverscape

Abstract: Anthropogenic partial barriers, such as low-head locks and dams, fragment social-ecological riverscapes and limit migratory fish access to historical spawning habitats, creating trade-offs between ecological conservation and human needs. Fish passage mitigation strategies at three low-head locks and dams on the Cape Fear River, North Carolina, across two contrasting mitigation regimes included (i) a nature-like fishway at LD1, (ii) conservation locking at LD2 and LD3, and (iii) environmental flow prescriptions when locks were inoperable. We evaluated passage of American shad and striped bass using acoustic telemetry and multistate models within a Bayesian framework to estimate upstream passage probabilities under varying flow conditions and management regimes. Passage probabilities for both species were higher in 2013–2015 when conservation locking was conducted. In contrast, passage declined when locks were inoperable and only e-flows allowed passage during dam submergence events in 2022–2023. Flow positively influenced passage, with strongest effects for striped bass; however, the nature-like fishway exhibited consistently low passage probability, and modifications did not improve passage probabilities. Given low passage probabilities during the recent mitigation period, improving longitudinal connectivity for diadromous fish in this river necessitates flexible, integrated operational, structural, and flow-based strategies. Possible future mitigation actions to improve fish passage could include resuming conservation locking, structural interventions such as bypass channel construction and dam height lowering that extends dam submergence, and continued use of e-flows.

8 Jun 2026

Emulation of Peak Storm Surge Across Extended Spatial Domains Using Separable Gaussian Process Techniques

Abstract: Data-driven emulation of peak storm surge has emerged as a popular strategy for overcoming limitations arising from the computational burden of high-fidelity hydrodynamic numerical models used within coastal risk assessment applications. The surrogate models used for this emulation are developed using suites of synthetic storm simulations, and once calibrated, can replace the original high-fidelity model to establish predictions for new storms. These predictions pertain to the geographic domain, and therefore nodal locations, covered by the original high-fidelity simulation suite. This creates a two-dimensional space for the peak surge predictions, with one corresponding to the storm features and the other to the spatial domain. Gaussian Process techniques have emerged as a widely popular surrogate modeling technique for peak surge emulation. In all GP implementations so far, the spatial variability has been incorporated in the analysis through the metamodel output, considering a multi-output GP implementation. This approach fails to explicitly model spatial dependencies for the peak surge. To address this shortcoming, this study examines an alternative implementation that considers spatial and storm feature variability as part of the metamodel input, establishing a surrogate model that simultaneously predicts the peak storm surge across both the spatial domain and the storm features. For computational tractability, a separable covariance function is considered for the GP, establishing separate kernels for the spatial and storm feature spaces. Particularly for the spatial domain, an adaptive covariance tapering formulation, which infuses sparsity in the corresponding covariance matrix, is adopted to support applications with a large number of nodal locations. A simultaneous calibration approach for the hyperparameters of the separate kernels is further proposed to improve emulation accuracy. Comparisons of computational efficiency and accuracy of the alternative GP implementations are established utilizing the Coastal Hazards System–North Atlantic database, with those employing the adaptive covariance tapering formulation evaluated under varying sparsity levels. The case study demonstrates that the simultaneous hyperparameter calibration is beneficial for the separable GP's predictive accuracy, particularly as it relates to the worst-performing nodes in the domain, and that the imposed sparsity level impacts the separable GP's ability to model non-stationary spatial trends in the domain.

8 Jun 2026

MoistViT: A Vision Transformer Model for Moisture Content Prediction of Wood Chips

Abstract: Moisture content in wood chips is a critical parameter for industries such as pelleting mills, bio-refineries, paper mills, and renewable energy production. The moisture level significantly influences both the quality of the final product and the efficiency of the production process. Consequently, accurate knowledge of moisture content is of substantial importance to wood chip-reliant industries. However, current methods for determining moisture content are either time-consuming or require costly equipment and specialized setups. Therefore, developing a quick and reliable method for assessing wood chip moisture content is imperative. To address this need, we evaluate fourteen Vision Transformer (ViT) architectures and introduce an optimized model, MoistViT, developed using Bayesian Optimization Hyperband (BOHB) for efficient hyperparameter tuning. Experiments on two wood chip image datasets (1600 total images) show that MoistViT achieves 91% accuracy and 92% F1-score on Source 1 and 93% accuracy and 93% F1-score on Source 2, outperforming all baseline models. Subsequently, a thorough analysis of failure cases has been carried out, including the identification of the most challenging groups of moisture levels. These analyses provide valuable insights into the complex task of determining moisture content from inherently heterogeneous wood chips. The proposed MoistViT demonstrates significant potential for real-time applications in relevant industries, which could ultimately lead to a streamlined production process.

5 Jun 2026

Environmental DNA Metabarcoding Elucidates Freshwater Mussel Diversity and Occupancy to Facilitate Improved Management and Conservation

Abstract: Freshwater mussels are considered among the most at-risk taxa in the world. As such, comprehensive monitoring assessments of what abiotic and biotic factors influence mussel occupancy will be vital for guiding effective conservation. Here, we analysed vertebrate and mussel environmental DNA metabarcoding data to explore the influence of biotic and abiotic factors on freshwater mussel populations. This study utilised water samples and tactile survey data collected from streams throughout Fort Johnson, Louisiana. Methods: We first evaluated the effectiveness of eDNA metabarcoding for characterising freshwater communities based on previous conventional tactile surveys. Next, we used eDNA metabarcoding analysis for freshwater mussels and vertebrate species alongside GIS-derived satellite remote sensing data to assess how various biotic and abiotic variables impact freshwater mussel eDNA occupancy. Our eDNA metabarcoding survey largely agreed with both historical and contemporary surveys on Fort Johnson, while uniquely detecting Louisiana pigtoe, a proposed threatened species under the US Endangered Species Act. We also found that eDNA detections and occupancy had strong seasonal variation, with increased read abundance and diversity in the spring. Vertebrate, fish, and predator diversity were strongly predictive of mussel occupancy, supporting the concept of land managers focusing on the entire ecosystem for mussel conservation. Lastly, we found that percent forest cover and drainage basin size influenced mussel eDNA occupancy, informing habitat associations for mussel species of interest. Our results demonstrate that combining eDNA metabarcoding of target and non- target species with occupancy modelling can provide insights into the ecology of freshwater mussels and is a useful tool to improve their conservation and management.

5 Jun 2026

Multitemporal Change Detection in the Coastal Zone: Literature Review

Abstract: Beach volume change is a primary metric for quantifying coastal change due to physical and anthropogenic forces. Volumes provide key inputs for the creation and maintenance of regional sediment budgets that inform engineering decisions and ensure the effective management of sediment. This special report provides a comprehensive literature review of the state of the art for developing beach volume change metrics, including methods, software and tools, and common sources of error. The reviewed literature indicates that common proxy-based methods for developing volumes (e.g., shoreline change analysis and beach profile change analysis) are limited in their applicability for study areas with alongshore geomorphic variability. A digital elevation model (DEM) of difference method used with high-resolution (e.g., 1 m DEM) datasets captures volumes over spatially variable geomorphologies more accurately; however, the literature notes limitations related to elevation dataset coverage and geometries used for aggregating volume quantities. Space-time cube methods enable cell-by-cell comparisons of volumes over multiple time periods within defined neighborhoods and provide additional insights, efficiencies, and flexibilities to afore-mentioned methods. A new beach volume framework is required to address limitations related to geomorphic variability, aggregation units, and dataset coverage.

4 Jun 2026

Brief Overview and Guide to Developing Monitoring and Adaptive Management Plans

Purpose: The purpose of this technical note is to summarizes key points on monitoring and adaptive management from the more detailed US Army Corps of Engineers (USACE) report ERDC/EL SR-19-9, “A Systems Approach to Ecosystem Adaptive Management: A USACE Technical Guide” and to provide a quick guide to developing monitoring and adaptive management plans (MAMPs) relevant to ecosystem restoration and mitigation projects. Although this report was written specifically for USACE projects, it is applicable to most restoration and mitigation projects. This guide does not supersede current or future USACE policy or guidance, nor is it applicable to private mitigation projects regulated by USACE.

4 Jun 2026

PFAS Interactions with ASTM Fat Clay and ASTM Ottawa Sand: Implications for Contamination from High-Concentration PFAS Sources Using Fourier Transform Infrared (FTIR) Spectroscopy

Purpose: This technical note seeks to understand the impact of high per- and polyfluoroalkyl substances (PFAS) concentrations on soils, specifically fat clay and Ottawa F-65 sand. This technical note also aims to understand the absorption and retention behaviors of PFAS in these two soil types and how the behaviors may vary because of the soil’s distinct properties.

4 Jun 2026

Efficacy of UVC Treatment on Hydrilla verticillata and Trapa spp.

Abstract: Hydrilla verticillata and Trapa spp. are invasive aquatic plants that pose serious challenges to freshwater ecosystems. In search of a nonchemical method to eradicate H. verticillata and Trapa spp., this study explores the application of UVC light to target the adult plant forms and the dormant turions of H. verticillata as well as the seedlings of Trapa spp. Contrary to our expectations, the experimental results demonstrated that UVC exposure had no significant effect on reducing the viability of either adult hydrilla plants or their turions. Despite treatment with a range of UVC doses, the plants remained viable and the turions were able to germinate successfully. UVC exposure did, however, cause a significant reduction in biomass for both Trapa species tested. These findings suggest that UVC light, at least under the conditions tested, is not an effective standalone strategy for controlling hydrilla but may be a useful nonchemical tool for controlling Trapa spp. Further research is required to explore alternative nonchemical methods or to refine the application parameters of UVC if it is to be further considered for eradication of these two invasive aquatic plants