Jason H. Knouft

Stream temperature influences aquatic ecosystem health, species distribution, and water quality. In snow-dominated watersheds, rain-on-snow (ROS) events regulate stream temperature by introducing cold meltwater, yet their role under future climate is uncertain. We investigate spatial variability of stream thermal regimes in the Great Lakes Basin (GLB) under historical (1960–2014) and future (2047–2074) scenarios using a basin-scale Soil and Water Assessment Tool (SWAT) enhanced with ROS and stream temperature modules. The model was calibrated with daily streamflow and snowpack water equivalent and driven with downscaled CMIP6 climate data. ROS events strongly cool streams in winter and spring, especially in colder northwest and northeast subbasins. However, under future warming, as ROS intensity declines, cooling weakens and stream temperatures increase across all seasons. Summer temperatures are projected to rise by 3–5°C in the southeast and northeast, with cumulative degree days (above 6°C) increasing and warming occurring earlier. These changes are linked to ROS-driven cooling and diminished summer flows. Thermal homogenization is projected across the basin, as historically cooler northern streams warm more rapidly, reducing spatial variability. Hot day duration shows strong negative correlations (−0.4 to −0.6) with ROS timing and intensity, particularly in the Lake Michigan and Ontario basins. The projected loss of ROS-induced cooling may elevate thermal stress for cold-water species, alter ecosystem metabolism, and increase invasive species risk. Adaptive strategies such as riparian shading and forest management will be critical to sustain thermal resilience.

Legal frameworks typically aim to protect environmental systems through regulations, treaties, and conservation measures. However, without scientifically informed enforcement, these policies may inadvertently exacerbate environmental degradation, particularly when addressing complex socio-environmental issues. We reviewed the development of China’s environmental legislation related to ecosystem protection in the Yangtze River watershed and evaluated its effectiveness by analyzing illegal fishing cases from 2015 to 2021, prosecuted under China’s Environmental Public Interest Litigation framework. Our findings reveal that court-ordered fish release remedies often undermine, rather than support, the sustainability of the Yangtze River ecosystem. This is primarily due to mismatches between the taxonomic identity of illegally caught fishes and those specified for release, species misidentification, and a bias toward economically valuable species in court-ordered release decisions. These unintended discrepancies between environmental protection goals and actual ecological outcomes underscore the need to integrate scientific expertise into legal practice to enhance the sustainability of socio-environmental systems.

Citizen science is personal. Participation is contingent on the citizens’ connection to a topic or to interpersonal relationships meaningful to them. But from the peer-reviewed literature, scientists appear to have an acquisitive data-centered relationship with citizens. This has spurred ethical and pragmatic criticisms of extractive relationships with citizen scientists. We suggest five practical steps to shift citizen-science research from extractive to relational, reorienting the research process and providing reciprocal benefits to researchers and citizen scientists. By virtue of their interests and experience within their local environments, citizen scientists have expertise that, if engaged, can improve research methods and product design decisions. To boost the value of scientific outputs to society and participants, citizen-science research teams should rethink how they engage and value volunteers.

Understanding why some clades diversify greatly while others do not is a major goal of evolutionary biology. Both abiotic and biotic factors are important in driving unequal morphological diversity across the tree of life. However, few studies have quantified how abiotic habitat and community composition differences influence unequal morphological diversification in spatiotemporally diffuse radiations. We use geometric morphometrics, abiotic habitat data generated by Geographic Information Systems (GIS) analyses, evolutionary simulations, and phylogenetic comparative methods to determine whether random evolution, habitat variation, competition for niches, or a combination of factors influenced the unequal body shape diversity of a Gondwanan freshwater fish radiation. We find that Neotropical characiform lineages, which exhibit substantially more body shape diversity than their African counterparts, occupy significantly more slope and elevation habitats than African lineages. Differences in habitat occupation between the continental radiations occur through a combination of likely competition with cypriniform fishes in Africa restricting access to higher slope and elevation habitats and significantly more low-elevation and slope habitats available in the Neotropics. Our findings suggest that spatiotemporally widespread radiations, like Characiformes, do not diversify across homogenized habitats and biotic assemblages, with differences in community structure and physical habitat playing an important role in driving unequal morphological diversification.

Biodiversity collections are experiencing a renaissance fueled by the intersection of informatics, emerging technologies, and the extended use and interpretation of specimens and archived databases. In this article, we explore the potential for transformative research in ecology integrating biodiversity collections, stable isotope analysis (SIA), and environmental informatics. Like genomic DNA, SIA provides a common currency interpreted in the context of biogeochemical principles. Integration of SIA data across collections allows for evaluation of long-term ecological change at local to continental scales. Challenges including the analysis of sparse samples, a lack of information about baseline isotopic composition, and the effects of preservation remain, but none of these challenges is insurmountable. The proposed research framework interfaces with existing databases and observatories to provide benchmarks for retrospective studies and ecological forecasting. Collections and SIA add historical context to fundamental questions in freshwater ecological research, reference points for ecosystem monitoring, and a means of quantitative assessment for ecosystem restoration.

Freshwater ecosystems play a key role in sustaining aquatic biodiversity. However, human alterations to watersheds and climate change are reducing critical habitat and the viability of populations of many aquatic species. The environmental changes have also had significant adverse impacts on water temperatures and streamflow. The changes in temperature and precipitation forecast over the next century are expected to affect the freshwater ecosystems and their biodiversity to an even greater extent than in the past. The aims of the HydroClim project are to provide openly accessible data on two key measures of stream conditions in the United States (US) and Canada for use in research, to increase public understanding of issues involving water resources, and to provide training opportunities for scientists who will be responsible for the conservation of freshwater biodiversity in the future. The project has used contemporary air temperature and precipitation data and future climate data from multiple Global Climate Model scenarios to generated high-resolution, spatially explicit, monthly streamflow and water temperature data for all watersheds across the US and Canada from 1950–2099 through multiple Soil and Water Assessment Tool (SWAT) hydrologic models. This presentation describes a cyberinfrastructure we developed for hosting the HydroClim data, consisting of a relational database and a web-based data portal that allows scientists to query and download the data. We have imported almost 1.9 billion HydroClim data records into the system. At the time of this submission, 1.3 billion records of historical data and predicted streamflow and water temperature model data are available in the HydroClim data portal for 26 watersheds in the United States. The HydroClim data are also being integrated with fish occurrence data from Fishnet 2, via the Fishnet 2 API (Application Programming Interface), which provides occurence data records for over 4.1 million species lots representing over 40 million specimens in ichthyological research collections. Our plan is to extract and merge environmental data from Hydroclim API, with fish occurrences containing geospatial information from the Fishnet 2 API, displaying the integrated data on web-based interactive hydrological maps in different time-series, and providing a tool for visualizing ecosystem diversity. The combined Hydroclim and Fishnet2 data can be used for ecological niche modeling applications, such as predicting the future distribution of threatened and endangered freshwater fish species. I will describe the cyberinfrastructure of HydroClim data portal and some of the ways the data can be used in biodiverisity research in the future.