14 May 2026

Engineering With Nature® Proving Grounds Innovation Handbook

Abstract: The Engineering With Nature® Proving Grounds Innovation Handbook provides a comprehensive framework for integrating innovative natural and nature-based features and sediment management strategies to address climate-driven hazards and increase resilience in coastal and fluvial environments. Developed through collaboration between engineers, scientist, landscape architects, and U.S. Army Corps of Engineers districts and divisions, the EWN Handbook showcases a diverse collection of projects within the four coasts of the United States and offers the wide range of approaches available to achieve multiple benefits (economic, ecological, and social) through the application of traditional engineering with natural infrastructure solutions. The document aims to offer practitioners ideas on how to incorporate EWN concepts and strategies in all phases to build more resilient, multifunctional projects that protect communities and ecosystems against future natural hazards.

11 May 2026

Native and Invaded-Range Surveys Provide Mixed Support for Enemy-Release of Nymphoides Peltata in the Invaded Range

Abstract: Natural or anthropogenic movement of plant species outside their historical ranges may result in exposure to new environmental conditions and a lack of natural enemies, thus promoting their establishment and spread into new areas. A biogeographical comparison of native and invasive populations can provide insight into the mechanisms of successful invasions and guide effective management strategies, such as biological control, by targeting plant traits that promote invasiveness. We studied the Eurasian aquatic plant, Nymphoides peltata, in situ in the native (China, Korea) and invaded (USA) ranges to determine whether there were differences in natural enemy attack rates (percent leaf damage, frequency of leaf herbivory or disease), productivity (plant cover, reproduction), and leaf traits (leaf elemental content, leaf toughness, dry matter content, specific leaf area) between areas. We also investigated whether there was evidence of a tradeoff between natural enemy attack and growth or reproduction, as would be predicted by invasion theory. Plant cover (23–29 % higher) and reproductive output (eight times more seeds / m2) were consistently higher in the invaded range. Leaf traits consistently differed between ranges, which we would expect if plants in the invaded range had fewer herbivores or other pests. The amount of leaf damage present was similar between ranges, but the frequency of herbivory was 50 % greater, on average, in the native than invaded range. Although we did not quantify suppression of N. peltata by natural enemies, we found evidence of more frequent herbivory in Asia and reduced reproduction and plant cover compared to the USA, which supports further investigation into viability of biological controls.

11 May 2026

High Temperatures will Likely Limit Establishment Success of the Brazilian Peppertree Thrips, Pseudophilothrips Ichini (Thysanoptera: Phlaeothripidae) in the USA, Despite Variation in Microhabitat Thermal Environments

Abstract: Biological control of the invasive tree, Schinus terebinthifolia Raddi, is under investigation to improve conservation and restoration of native plant communities in the continental USA. Release and monitoring of the Brazilian peppertree thrips, Pseudophilothrips ichini, is ongoing in multiple states and climate zones but establishment has been variable. In particular, establishment has not been confirmed in hot, southern Texas locations despite release of over 150,000 thrips across four locations since 2022. To understand whether thermal limitations may preclude use of P. ichini in some regions, we investigated upper and lower thermal limits of P. ichini. We measured upper limit of chill injury zone (ULCIZ) and lower limit of thermal injury zone (LLTIZ) in the laboratory under multiple combinations of temperature and exposure duration then modeled spatial variation in survival based on detailed weather data over 20 years. Additionally, we documented microhabitat variation in temperature extremes in three release sites in south Texas to evaluate whether thermal refugia exist due to variation in microhabitat conditions. Based on LLTIZ and ULCIZ, thermal injury accumulates rapidly at temperatures above 33.08 ± 0.15 ◦C and more slowly at decreasing temperatures below 7.85 ± 0.82 ◦C. Temperatures within the canopy of S. terebinthifolia in the field varied widely and produced a range of predicted mortality, with temperatures at the base of trees that were more moderate in both summer and winter. We determined that, based on the current distribution of S. terebinthifolia in the USA, climate suitability differs between states. Suitability of Florida locations was deemed highly to moderately suitable across seasons, but most Texas locations were unsuitable, including previous release locations in south Texas. These findings suggest releases should continue through most of Florida, in areas of southern California, and locations along the northern gulf coast of Texas. Additionally, augmentative releases of P. ichini during mild seasons may provide opportunities for use of this biological control agent to manage S. terebinthifolia in Texas.

8 May 2026

Development of a Trace Element Signature Library Across a Large Watershed for Assessing Large-Scale Fish Movement Patterns

Abstract: Using trace element or stable isotope analysis has proven to be an effective means to characterize early life history and large-scale movement patterns in fishes. Target species are assessed for analyte concentrations occurring in calcified hard structures and compared to signatures noted from associated watersheds. However, this approach assumes analyte absorption occurs in proportion to their availability, and success relies heavily on the ability to identify unique water chemistry signatures between neighboring watersheds within a defined study area. Our objective was to establish a trace element signature profile for major tributaries occurring within the Mississippi River Valley (MRV). Water samples were obtained from 49 stations and evaluated for the presence and relative concentration of Ba, Sr, Ca, Fe, and Li. Analyte concentrations (milligrams per liter) varied across the sampled stations, although Li occurred at only four stations, primarily in the upper reaches of the MRV, and provided little discriminatory use. Concentrations of Fe and Ca depicted an inverse relationship, with Ca having higher concentrations in the upper third of the MRV while Fe typically had higher concentrations in the lower third. Ratios of Ba:Ca and Sr:Ca (millimole per mole) exhibited the greatest utility for delineating river-specific or reach-specific signatures.

7 May 2026

An All-Hazards Return on Investment (ROI) Model to Evaluate U.S. Army Installation Resilient Strategies

Abstract: The paper describes our project to develop, verify, and deploy an All-Hazards Return of Investment (ROI) model for the U.S. Army Engineer Research and Development Center (ERDC) to provide army installations with a decision support tool for evaluating strategies to make existing installation facilities more resilient. The need for increased resilience to extreme weather caused by climate change was required by U.S. code and DoD guidance, as well as an army strategic plan that stipulated an ROI model to evaluate relevant resilient strategies. During the project, the ERDC integrated the University of Arkansas designed model into a new army installation planning tool and expanded the scope to evaluate resilient options from climate to all hazards. Our methodology included research on policy, data sources, resilient options, and analytical techniques, along with stakeholder interviews and weekly meetings with installation planning tool developers. The ROI model uses standard risk analysis and engineering economics terms and analyzes potential installation hazards and resilient strategies using data in the installation planning tool. The ROI model calculates the expected net present cost without the resilient strategy, the expected net present cost with the resilient strategy, and ROI for each resilient strategy. The minimum viable product ROI model was formulated mathematically, coded in Python, verified using hazard scenarios, and provided to the ERDC for implementation.

6 May 2026

Economic Valuation and Natural Resource Damage Assessment Methods at Myakka River State Park, Florida

Abstract: The growing population and distribution of invasive wild pigs across vulnerable ecological communities has emerged as a significant issue, and there is not a standardized ecological-economic framework to precisely measure and value the impact of wild pigs to natural resources. The FY24 research presented here is year four of a 4-year research plan to develop a user-friendly ecological-economic framework for rapid assessment and valuation of wild pig damage to wetlands. Building off the findings from research conducted at Somerville Lake, Texas, and Richard K. Yancey Wildlife Management Area, Louisiana, this FY24 research took place at Myakka River State Park, Florida. Research objectives for FY24 included adapting the ecological-economic framework to a different landscape type, refining and broadening the artificial intelligence–based economic valuation approach by valuing a variety of natural communities, and improving the setup of the before-after-control-impact study design estimating damage reduction after a targeted control effort. Across the study area, we estimated that the benefits provided by the natural communities lost to wild pigs over a 1-year period were $273,525 (80% confidence interval: $72.684 and $920.883), and an aerial gunning control effort produced an estimated 685% return on investment in avoided losses 4 weeks postmanagement.

5 May 2026

Uptake and Elimination of Per-and Polyfluoroalkyl Substances in Earthworms Exposed to Spiked Artificial Soil or Aqueous Medium

Abstract: We investigated the accumulation of per-and polyfluoroalkyl substances (PFAS) in earthworms (Eisenia andrei). Uptake kinetics and bioaccumulation factors (BAFs) were determined using a mixture of 16 PFAS by exposing earthworms to spiked artificial soil for up to 28 days. Two treatments were used, with the low treatment targeting environmentally relevant concentrations. The concentrations of PFAS remained relatively unchanged during the exposures and statistically significant rates of uptake were estimated for most individual PFAS. For the 0.01 mg/kg treatment (target concentration of each PFAS), steady state was reached for all PFAS except perfluoroheptanoic acid, perfluorohexanesulfonic acid (PFHxS), perfluorooctanesulfonic acid (PFOS), perfluorotetradecanoic acid (PFTeDA), and perfluorotridecanoic acid. For the 0.01 mg/kg treatment, bioaccumulation factors (BAF; kg/kg-dry wt) ranged from 4–49 for most PFAS but were higher for PFHxS (72), PFTeDA (271), and perfluoroundecanoic acid (299). Organic carbon–normalized BAFs were within the range of published values. The BAF values increased with increasing length of the alkyl chain for perfluoroalkyl carboxylic acids (PFCAs), but not for perfluoroalkyl sulfonic acids (PFSAs). Uptake rates and BAFs were lower for the 1 mg/kg treatment, typically by over one order of magnitude, likely because of sublethal physiological impairment. Fast and steep decreases in tissue concentrations of PFAS occurred when earthworms were transferred to clean soil, even for long chain PFAS, agreeing overall with previous reports. However, measured elimination rates were faster than predicted from the uptake experiments and the causes remain unknown. Bioaccumulation of PFAS was also investigated in exposures to aqueous medium for up to 7 days to derive bioconcentration factors (BCFs). Comparison of BCFs and BAFs suggests that uptake from soil may have higher relevance than dermal uptake from porewater for long-chain PFCAs and PFSAs.

5 May 2026

Carrying Capacity in Human-Environment Interactions: A Systematic Review

Abstract: The concept of carrying capacity has been applied broadly to various biological and social contexts. This article presents a systematic review of the carrying capacity literature as applied to human-occupied environments. The review evaluates underlying approaches and methods and explores the utility and limitations of the concept’s applications. Prominent tools and approaches identified include evaluation index systems, ecological footprint analysis, the Cifuentes method, multi-objective optimization, system dynamics, fuzzy mathematics, and remote sensing and geographical information systems. Our findings indicate that, despite its origins, carrying capacity research is rarely concerned with the survival of human communities; instead, it is often invoked to understand the implications of human population growth and urbanization on living and sufficiency standards. The majority of identified carrying capacity studies did not define a strict upper boundary, demonstrating the utility of carrying capacity as a rhetorical strategy to galvanize action before system degradation eliminates options. The concept of carrying capacity, when applied to human-managed and constructed environments, increasingly reflects socioeconomic factors and quality of life considerations, underscoring subjective social constraints and societal tolerance levels rather than physical limitations on population survival.

5 May 2026

Behavioral Responses of Silver Carp to Underwater Acoustic Deterrent Sounds

Abstract: Invasive carps continue to spread across the Mississippi River basin, posing significant ecological risk. Identifying technologies to slow their dispersal is critical. The use of sound has been proposed as a method to modify the behavior of Silver Carp Hypophthalmichthys molitrix, offering a nonstructural deterrent strategy. Silver Carp implanted with acoustic transmitters were released into earthen ponds equipped with telemetry arrays. The fish were exposed to a 30-min playback of three underwater sounds (chirp saw, chirp square, and 100- hp boat motor). Movement trajectories were analyzed using a two-state hidden Markov model to estimate the effects of environmental and experimental variables on fish behavior. The results of the hidden Markov model supported two behavioral states. State 1 was characterized by longer step lengths and greater directional persistence in turning angle, indicative of heighted activity. State 2 was defined by shorter step lengths and less directional persistence, suggesting reduced activity. Silver Carp that were exposed to the chirp square sound had an increased likelihood of entering state 1, whereas the 100-hp boat motor sound promoted transitions to state 2. Underwater sounds distinctly influenced the movement of Silver Carp in earthen ponds. The chirp square sound elicited heightened activity levels, demonstrating potential for use in acoustic deterrent applications. However, the response of Silver Carp to these sounds may be influenced by the size of the study environment or the absence of natural drivers of fish behavior, such as food or reproduction. This study contributes to the development of nonstructural, species-specific deterrent systems by identifying sounds that influence the behavior of invasive carps. The application of sound- based methods may play a critical role in integrated pest management strategies for invasive carps, potentially limiting their spread while minimizing effects on native species.

5 May 2026

Designing Sortable Guilds for Multispecies Selective Fish Passage

Abstract: The importance of connectivity for freshwater organisms is widely recognised, yet in-stream barriers associated with population declines and increased risk of extinction remain globally ubiquitous. Despite their negative consequences, these barriers can protect aquatic communities by limiting the spread of invasive species, leading to conflicting management goals in some regions. Selective fish passage is a solution for the conflicting goals of passing native, desirable species while restricting the spread of invasives. Approaches that can target groups of species sharing similar attributes (i.e. guilds) are likely to be more efficient than those that target species individually, particularly in taxonomically diverse systems. We explored the guild structure of 220 Great Lakes freshwater fishes based on morphological, phenological, physiological and behavioural attributes associated with passage and movement. We identified five distinct guilds as well as the attributes most important for defining these groupings: maximum total length, trophic level, relative eye size, spawning temperature, spawning season, presence/absence of ampullary electroreceptors and the presence/absence of hearing specialisations. The approaches outlined in this work can be generalised to enhance selective fish passage in aquatic ecosystems worldwide.