Alex W. Bajcz

The common carp ( Cyprinus carpio ) is an economically and ecologically significant species. It is both one of the most highly produced fish in aquaculture globally and a persistent, widespread invasive species. Research efforts focused on understanding its biology, improving traits for aquaculture, and generating next‐generation carp control technologies, all of which benefit from reliable and robust protocols for spawning and genetic transformation. Here, we report a retrospective analysis of carp husbandry and spawning experiments to identify key parameters influencing the successful production of viable embryos in laboratory settings. Next, we produced brightly fluorescent transgenic common carp using the Tol2 transposase system to deliver DNA encoding a fluorescent reporter and demonstrated the transgene was heritable. We also attempted to optimize other protocols related to the production of genetically modified common carp, such as finding the ideal cryoprotectant exposure time for sperm cryopreservation, testing egg de‐adhesion solutions, and identifying conditions affecting storage time of unfertilized eggs and sperm. Lastly, we demonstrated how a fluorescent reporter construct could be used to select for gene‐edited carp at multiple stages of development. Together, this work demonstrates how optimization of many parts of the genetic modification process can greatly enhance its efficiency.

A collection of enhancements to 'ggplot2', with a focus on creating Universally Designed, accessible graphs easily and quickly.

Even when data needed to address complex, high‐priority ecological questions exist, when they are collected by many different entities for diverse purposes, they can be difficult to discover and unify. Web applications can address these challenges by serving as submission portals that clean and combine data programmatically. Furthermore, web apps can incentivize contributions—e.g., by providing public recognition and novel visualizations for reporting—while insulating users from needing to apply programming skills or interoperability practices. Here, we introduce P.I. Charter , an R Shiny web application that solicits, tidies, compiles, and shares point‐intercept (PI) aquatic plant survey data collected across Minnesota, USA by dozens of entities. We summarize the app's features and how these align with our goals regarding ease of use, accessibility, education, open access, and user experience. Since P.I. Charter 's launch, it has received thousands of visitors and hundreds of submissions. Familiar contributors can submit surveys in minutes, and satisfaction with the app is high. We present four case studies that show how the app and its database could be used to: (1) better plan and conduct future surveys, (2) strategize surveillance for new cryptic invasions, (3) investigate relationships between species occurrence and environmental factors, and (4) elucidate long‐term trajectories of plant community composition in lakes responding to global change processes and management. Apps like P.I. Charter could revolutionize data aggregation in contexts wherein large data volumes are gathered and stored disparately. For us, developing P.I. Charter was relatively straightforward, but we caution that using R Shiny to build a complex, science‐focused web application is not without challenges, especially with respect to achieving digital accessibility. Nonetheless, P.I. Charter 's capacity to make fuller use of hard‐earned data to address ecological questions has proven so valuable we wish to share our experiences so they may serve as a model for others.

The partial reinforcement extinction effect (PREE) occurs when a conditioned response is more resistant to extinction when reinforced unpredictably versus continuously. The PREE has been observed in many species; however, our knowledge of the PREE in fishes is limited. In this study, we investigated two different reinforcement methods, continuous and partial, while using Pavlovian conditioning to acoustically condition common carp ( Cyprinus carpio ), a highly invasive species, to swim into a feeding ring (conditioned behaviour) where they would receive a food reward at the onset of a 400 Hz sound stimulus. The extinction rates of the conditioned behaviour were compared following cessation of the food reward. Using binomial generalized linear mixed-effect regressions we showed that tanks subjected to partial reinforcement were expected to have a higher proportion of carp exhibiting the conditioned behaviour up to two times longer than tanks subjected to continuous reinforcement, consistent with the PREE. Carp in partial reinforcement tanks continuously responded for up to 30 days, while responses in continuous reinforcement tanks typically ceased by day 9. Our findings support common carp management strategies that use baiting to train carp to form feeding aggregations that can be removed en masse from lakes and suggest that such baiting strategies may benefit from partial conditioning protocols, saving on both labour and bait.

Overland transport of recreational boats facilitates movement of aquatic invasive species (AIS) between waterbodies. Once established, AIS can have detrimental and difficult-to-manage ecological impacts. Prevention, the most cost-effective AIS management strategy, is one strategy in which management agencies focus on reducing spread by implementing programs like boater education, watercraft inspection, and hot water decontamination. Given resource constraints, deciding which management actions to take, and where to implement them, remains challenging. To address this gap, we developed and tested a new application entitled “ Intervention Impact ” to add to the AIS Explorer, an online AIS program-planning dashboard ( www.aisexplorer.umn.edu ). Intervention Impact assists managers by simulating AIS spread scenarios based on user-defined lake-level budget, effort, and intervention effectiveness values, enabling comparisons between scenarios in search of the “best” approaches. Outputs include estimates for levels of risk reduction and the numbers of new infestations averted for both zebra mussel and starry stonewort. We demonstrate the application’s utility using input conditions based on Cass County, Minnesota (USA), as a case study. The case study shows that each prevention strategy involves trade-offs and might be more or less preferable under different budget constraints. It also demonstrates the value of a data-driven approach to development of AIS prevention plans.

To efficiently detect aquatic invasive species early in an invasion when control may still be possible, predictions about which locations are likeliest to be occupied are needed at fine scales but are rarely available. Occupancy modeling could provide such predictions given data of sufficient quality and quantity. We assembled a data set for the macroalga starry stonewort (Nitellopsis obtusa) across Minnesota and Wisconsin, USA, where it is a new and high-priority invader. We used these data to construct a multi-season, single-species spatial occupancy model that included biotic, abiotic, and movement-related predictors. Distance to the nearest access was an important occurrence predictor, highlighting the likely role boats play in spreading starry stonewort. Fetch and water depth also predicted occupancy. We estimated an average detection probability of 63% at sites with mean non-N. obtusa plant cover, declining to ~ 38% at sites with abundant plant cover, especially that of other Characeae. We recommend that surveyors preferentially search for starry stonewort in areas of shallow depth and high fetch close to boat accesses. We also recommend searching during late summer/early fall when detection is likelier. This study illustrates the utility of fine-scale occupancy modeling for predicting the locations of nascent populations of difficult-to-detect species.

Early-career faculty (ECF) are faced with maintaining excellence in teaching and research for tenure. However, many enter academia with little or no teaching experience. Madison Teaching and Learning Excellence, a year-long professional development program, was designed to mitigate these pressures and help faculty become fast, efficient, and effective teachers. The authors evaluated this program on participants’ use of learner-centered course designs and classroom practices compared with non-participants and also measured challenges encountered by ECF. Participants’ gains in effective course design were positive, stable, and transferable to other courses. Participants reported feeling more prepared for tenure review and possessed a heightened self-awareness and assessment of their teaching. Although participants scored moderately high on measures of learner-centered practices, their scores were similar to non-participants. The authors hope their evaluation will inform faculty development programs; they summarize challenges they encountered to spur development of better evaluation tools that balance practitioners’ needs and available resources.

Soil freeze–thaw cycles (FTCs) profoundly influence biophysical conditions and modify biogeochemical processes across many northern‐hemisphere and alpine ecosystems. How FTCs will contribute to global processes in seasonally snow‐covered ecosystems in the future is of particular importance as climate change progresses and winter snowpacks decline. Our understanding of these contributions is limited because there has been little consideration of inter‐ and intrayear variability in the characteristics of FTCs, in part due to a limited appreciation for which of these characteristics matters most with respect to a given biogeochemical process. Here, we introduce the concept of effective FTCs: those that are most likely linked to changes in key soil processes. We also propose a set of parameters to quantify and characterize effective FTCs using standard field soil temperature data. To put these proposed parameters into effective practice, we present FTCQuant, an R package of functions that quantifies FTCs based on a set of user‐defined parameter criteria and, importantly, summarizes the individual characteristics of each FTC counted. To demonstrate the utility of these new concepts and tools, we applied the FTCQuant package to re‐analyze data from two published studies to help explain over‐winter changes to N₂O emissions and wet‐aggregate stability. We found that effective FTCs would be defined differently for each of these response variables and that effective FTCs provided a 76 and 33% increase in model fit for wet‐aggregate stability and cumulative N₂O emission, respectively, relative to conventional FTC quantification methods focusing on fluctuations around 0 °C. These results demonstrate the importance of identifying effective FTCs when scaling soil processes to regional or global levels. We hope our contributions will inform future deductions, hypothesis generation, and experimentation with respect to expected changes in freeze–thaw cycling globally.

This study explored the relationships between student background and academic performance in college introductory environmental science (ES) courses at a large U.S. research university with the premise that this analysis may inform teaching practices, curricula, and efforts to increase retention. We surveyed over 700 students across eleven introductory ES courses and used multiple linear mixed-effects regressions to model the data. We found that students who grew up in rural settings or who had frequent childhood interactions with natural environments earned higher grades, on average, than students from urban settings or with fewer childhood interactions with natural environments. Our results indicate that students reporting frequent childhood interactions with forests, for example, were projected to earn grades up to 1.5 letter grades higher in these courses than students with no such interactions. In addition, students with frequent childhood interactions with nature were likelier to report that such interactions helped them in their ES course, suggesting that these students may recognize the value of these experiences. Greater interest in the subject matter also correlated with higher ES course grades, whereas amount of prior ES coursework did not. We discuss the possible implications of these correlations for ES academic performance and educational practice.