Central Minnesota Research Articles

Forest and Biodiversity 2: A tree diversity experiment to understand the consequences of multiple dimensions of diversity and composition for long‐term ecosystem function and resilience

Abstract We introduce a new “ecosystem‐scale” experiment at the Cedar Creek Ecosystem Science Reserve in central Minnesota, USA to test long‐term ecosystem consequences of tree diversity and composition. The experiment—the largest of its kind in North America—was designed to provide guidance on forest restoration efforts that will advance carbon sequestration goals and contribute to biodiversity conservation and sustainability. The new Forest and Biodiversity (FAB2) experiment uses native tree species in varying levels of species richness, phylogenetic diversity and functional diversity planted in 100 m2 and 400 m2 plots at 1 m spacing, appropriate for testing long‐term ecosystem consequences. FAB2 was designed and established in conjunction with a prior experiment (FAB1) in which the same set of 12 species was planted in 16 m2 plots at 0.5 m spacing. Both are adjacent to the BioDIV prairie‐grassland diversity experiment, enabling comparative investigations of diversity and ecosystem function relationships between experimental grasslands and forests at different planting densities and plot sizes. Within the first 6 years, mortality in 400 m2 monoculture plots was higher than in 100 m2 plots. The highest mortality occurred in Tilia americana and Acer negundo monocultures, but mortality for both species decreased with increasing plot diversity. These results demonstrate the importance of forest diversity in reducing mortality in some species and point to potential mechanisms, including light and drought stress, that cause tree mortality in vulnerable monocultures. The experiment highlights challenges to maintaining monoculture and low‐diversity treatments in tree mixture experiments of large extent. FAB2 provides a long‐term platform to test the mechanisms and processes that contribute to forest stability and ecosystem productivity in changing environments. Its ecosystem‐scale design, and accompanying R package, are designed to discern species and lineage effects and multiple dimensions of diversity to inform restoration of ecosystem functions and services from forests. It also provides a platform for improving remote sensing approaches, including Uncrewed Aerial Vehicles (UAVs) equipped with LiDAR, multispectral and hyperspectral sensors, to complement ground‐based monitoring. We aim for the experiment to contribute to international efforts to monitor and manage forests in the face of global change.

Analysis of bigmouth buffalo Ictiobus cyprinellus spawning phenology in Minnesota reveals 50-year recruitment failure and conservation concern

The bigmouth buffalo Ictiobus cyprinellus (Catostomidae) is a freshwater fish native to North America that is known for its longevity. During the 1970s, the bigmouth buffalo was recorded as declining in Canada, Minnesota, and North Dakota and became a protected species in Canada. In the USA, population declines are exacerbated by wasteful recreational bowfishing, lack of fisheries management, and overall lack of knowledge. However, recent studies have revealed the exceptional lifespan of bigmouth buffalo, their negligible senescence, slow growth, delayed maturity, and episodic recruitment. Yet little is known about the spawning phenology of bigmouth buffalo, nor their age demographics in east central Minnesota. In this 2021–2023 study of bigmouth buffalo from Rice Lake National Wildlife Refuge we found that 99.7% (389 of 390) of the extant population hatched prior to 1972 despite annual spawning in Rice Lake. Moreover, recruitment success declined significantly since water control measures were established (1953). We found males arrive to spawning grounds with females but depart later, that both the midpoint and duration of spawn significantly vary across years, and that more massive females of the same age range invest disproportionately more in ovaries. Extensive post-spawn seining revealed bigmouth buffalo young-of-the-year in low numbers, but by mid-to-late summer they were no longer evident having likely succumbed to predation. Overall, these findings thoroughly reveal one of the oldest populations of vertebrate currently known (median age of 79 years as of 2024) and expose the stark vulnerability of a bigmouth buffalo population for which substantial recruitment has not occurred for more than six decades. Multiple lines of evidence indicate that the long-lived bigmouth buffalo is vulnerable, that a precautionary approach is immediately needed, and that the unlimited and unregulated kill-fishery be closed.

A framework for modeling the impacts of adaptive search intensity on the efficiency of abundance surveys.

When planning abundance surveys, the impact of search intensity on the quality of the density estimates is rarely considered. We constructed a time-budget modeling framework for abundance surveys using principles from optimal foraging theory. We link search intensity to the number of sample units surveyed, searcher detection probability, the number of detections made, and the precision of the estimated population density. This framework allowed us to determine how a searcher should behave to produce optimized density estimates. Using data collected from quadrat and removal surveys of zebra mussels (Dreissena polymorpha) in central Minnesota, we applied this framework to evaluate potential improvements. We found that by tuning searcher behavior, density estimates from removal surveys of zebra mussels could be improved by up to 60% in some cases, without changing the overall survey time. Our framework also predicts a critical population density where the best survey method switches from removal surveys at low densities to quadrat surveys at high densities, consistent with past empirical work. In addition, we provide simulation tools to apply this form of analysis to a number of other commonly used survey designs. Our results provide insights into how to improve the performance of many survey methods in high-density environments by either tuning searcher behavior or decoupling the estimation of population density and detection probability.

Food as Medicine: FOODRx for Patients with Diabetes and Cardiovascular Disease in Central Minnesota—A PILOT STUDY

The number of food-insecure individuals with diabetes is on the rise. FOODRx is a supplemental healthy food intervention program that gave disease-appropriate food boxes to food-insecure patients with diabetes at their care clinic and included nutrition and recipe materials in the patient’s preferred language (English, Spanish, or Somali). Implemented over a twelve-month period, we analyze FOODRx participants’ pre and post clinical measures, health care usage, and program/clinic satisfaction, and found that participation was linked to post improvements in fasting glucose and HgbA1c levels, reductions in ER visits and healthcare costs, and a decline in patients choosing between medication and food. Glucose levels decreased from 214 to 187 mg/dL and HgbA1c levels decreased from 9.6% to 9.1%. Average ER visits dropped from 1.21 to 1 visit and the reductions in healthcare costs were reflected in a decrease of an average of USD 250,000 in insurance claims. Patients were less likely to experience food insecurity, as measured in number of meals skipped and levels of hunger. Finally, the program improved patient satisfaction with the cultural responsiveness of the information shared with them.

Minnesota city used anti‐crime laws against people with MI

Last year, a federal investigation found that Anoka, a suburb of Minneapolis, illegally discriminated against residents with mental health disabilities by giving landlords weekly reports, over five years, revealing personal medical information of renters who received multiple emergency calls to their homes, the Associated Press (AP) reported on Feb. 4. In at least 780 cases, the city also shared details about mental health crises and even how people had tried to kill themselves, all under the guise of enforcing an ordinance designed to deter crime and eliminate public nuisances, the U.S. Department of Justice said. City laws like those used in Anoka — among hundreds of ordinances enacted across the U.S. since the 1990s — have long drawn criticism for unfairly targeting poorer neighborhoods and communities of color, the AP reported. Now they are under scrutiny as sources of mental health discrimination. “It's horrific,” said Elizabeth Sauer, an attorney for Central Minnesota Legal Services, which serves low‐income people. “Can you imagine having the most intimate details of your life just broadcast to every landlord in the city you live in?” Anoka's “crime‐free” ordinance was enacted in 2016 and at the time, city council members said they were fighting crime and making neighborhoods safer. Reported crimes in Anoka dropped by 57% from 2016 through 2022, according to FBI statistics, though crime rates were falling before then. Last year, Maryland prohibited landlords from evicting tenants over the number of emergency calls to their addresses and prohibited cities and counties from penalizing landlords for emergency calls. A California law that took effect on Jan. 1 greatly limits cities' use of such ordinances and advocates expect a push for similar legislation in Illinois and Minnesota. While proponents of such ordinances have argued that they protect people who live in fear, critics have said that rethinking them is necessary to stem cycles of homelessness that many with mental illness face. Housing advocates point to tenant unions and tenant‐run housing cooperatives as ways to mitigate the issues that nuisance laws are intended to target.

Flow Rate and Volume Estimates from Variable Frequency Drive Operated Drainage Sump Pumps

Highlights This article provides an overview of operations and benefits of using a variable frequency drive to operate agricultural subsurface drainage system sump pumps. A methodology is proposed to monitor flow rates leaving agricultural subsurface drainage pump stations via a MATLAB algorithm. The results of this research were mixed because the algorithm estimates did not always match with the corresponding flowmeter measurements. Abstract. Subsurface drainage plays a crucial role in excess water removal through perforated pipes buried in the soil. The Red River Valley of eastern North Dakota and west central Minnesota often requires pumped drainage outlets due to its flat topography, with many modern systems incorporating variable frequency drives (VFD) for improved efficiency. VFDs adjust pump speeds to match drainage needs, but this dynamic operation complicates accurate flow rate estimation for edge-of-field monitoring. This project aimed to devise an automated method for calculating flow rate estimates from VFD pumping systems involving tank geometry, operational water levels, and pump duty cycling. Linear regressions with calibration data from a transit-time ultrasonic flowmeter produced mixed outcomes. Some linear regressions revealed errors in calculated versus measured flow rate of =14%, while other regressions showed errors nearing 40%. To address this, future efforts should explore methods incorporating the pump’s electrical characteristics. This approach would provide a more accurate representation of the unstable and intricate pumping operations during transient conditions. Keywords: Edge-of-field monitoring, Flow rate, Pump, Red River Basin, Subsurface drainage, Variable frequency drive

Spatial and temporal variability of mercury in Upper and Lower Red Lake Walleye.

Mercury is a global pollutant that is released into our environment by natural and anthropogenic processes resulting in extensive studies of mercury cycling in aquatic ecosystems, and the issuance of human-health-based fish-consumption advisories. We examined total mercury concentrations in Walleye Sander vitreus from Upper and Lower Red Lakes, located in north central Minnesota, between 2019 and 2020. Sampled Walleye (n = 265) ranged from 158 to 610 mm in total length from an age range of young-of-the year to 16 years. Mercury concentrations within the Walleye ranged from 0.030 mg/kg to 0.564 mg/kg (x̄ = 0.179 ± 0.105 mg/kg; x̄ = mean ± sd, all fish-mercury concentrations expressed on wet-weight basis). The best supported model for predicting mercury concentrations in Red Lake Walleye included the independent variables: length, age, sex, and lake basin. This model indicated that there was a significant difference in mercury concentrations between Upper and Lower Red Lake (x̄ = 0.215 ± 0.117 and 0.144 ± 0.077 mg/kg, respectively), and also suggests that individuals who rely on fish for subsistence should target Walleye that are ≤ 400 mm from Lower Red Lake. Observed differences in mercury concentrations could be linked to wetland area influences, fish growth rates, and physicochemical parameters between the two basins. Given that our results illustrated a significant difference in fish-mercury concentrations between basins, future pollutant monitoring efforts should treat Upper and Lower Red Lake as separate lakes and not assume that data from one basin can apply to the other.

A comparison of survey method efficiencies for estimating densities of zebra mussels (Dreissena polymorpha).

Abundance surveys are commonly used to estimate plant or animal densities and frequently require estimating detection probabilities to account for imperfect detection. The estimation of detection probabilities requires additional measurements that take time, potentially reducing the efficiency of the survey when applied to high-density populations. We conducted quadrat, removal, and distance surveys of zebra mussels (Dreissena polymorpha) in three central Minnesota lakes and determined how much survey effort would be required to achieve a pre-specified level of precision for each abundance estimator, allowing us to directly compare survey design efficiencies across a range of conditions. We found that the required sampling effort needed to achieve our precision goal depended on both the survey design and population density. At low densities, survey designs that could cover large areas but with lower detection probabilities, such as distance surveys, were more efficient (i.e., required less sampling effort to achieve the same level of precision). However, at high densities, quadrat surveys, which tend to cover less area but with high detection rates, were more efficient. These results demonstrate that the best survey design is likely to be context-specific, requiring some prior knowledge of the underlying population density and the cost/time needed to collect additional information for estimating detection probabilities.

Increased Light Exposure Decreases Lichen Abundance on Linden Trees in the Prairie Grassland Biome of West Central Minnesota

Increased Light Exposure Decreases Lichen Abundance on Linden Trees in the Prairie Grassland Biome of West Central Minnesota

Water-quality outcomes of wetland restoration depend on hydroperiod rather than restoration strategy

Land managers increasingly use wetland restoration to improve water quality, particularly in cultivated landscapes. In agricultural wetland restoration, managers regularly excavate accumulated sediments eroded from the surrounding landscape to increase water storage capacity, decrease invasive species cover, or improve water quality. However, it is unclear whether the effects of sediment excavation are influenced by wetland hydroperiod. Additionally, we lack data on how long excavation effects persist in restored wetlands. We examined dissolved nutrient concentrations (i.e., NH4+, NO3–, total dissolved N, soluble reactive P, total dissolved P, and dissolved organic C) as proxies for water quality in 54 restored agricultural wetlands ranging from 1 to 10 y post-restoration in the Prairie Pothole Region of west central Minnesota, USA. In 26 of these wetlands, restoration practitioners restored natural (i.e., either seasonal or semipermanent inundation) hydrological regimes by removing subsurface tile drainage and plugging surface drainage ditches (business-as-usual treatment). In 28 wetlands, practitioners removed accumulated sediment and redeposited it on the surrounding landscape (excavated treatment) prior to restoring hydrology. We found that wetlands in the excavated treatment group initially experienced reduced dissolved P concentrations, but over time P levels increased, particularly in wetlands with shorter hydroperiods. Excavated wetlands had lower NH4+ and dissolved organic C concentrations compared with business-as-usual wetlands, but the trend was driven by differences between restoration treatments in semipermanent wetlands. N and P dynamics were almost universally related to hydroperiod, both immediately following restoration and over the ensuing years. We postulate that the effects of hydroperiod are likely related to differences in redox conditions via direct mechanisms (water level fluctuations related to hydroperiod) and indirect mechanisms (development of dense emergent macrophyte communities in seasonal wetlands). In basins with seasonal hydroperiod, inorganic N concentrations decreased over time and inorganic P concentrations increased, suggesting net P mobilization concurrent with growing N limitation. Our results illustrate that hydroperiod regulates the expression of legacy P following wetland restoration, with little long-term effect of sediment removal on water quality outcomes.

Effect of Irrigation Scheduling Methods on Maize Grain Yield and Nitrate Leaching in Central Minnesota

Highlights Four irrigation scheduling methods were compared for maize yield vs nitrate-N losses. Yield was similar with SM, CB, and EPIC, and lower for IMA irrigation scheduling. Nitrate-N leaching losses were highly dependent on precipitation as well as on the rate and frequency of irrigation. IMA and EPIC methods should be adopted with further calibration. ABSTRACT. Coarse-textured soils in the Great Lakes states have limited water holding capacity, which makes irrigation essential to obtain optimum yields for maize; however, excess irrigation has the potential to contaminate ground and surface water resources through deep seepage of applied fertilizers, making irrigation management critical. The objective of this study was to evaluate the impact of different strategies for agricultural irrigation water management on maize grain yield and nitrate leaching losses. In this three-year study (2019-2021), the following four irrigation scheduling strategies were compared under continuous maize cropping systems at two sites in Central Minnesota, Becker and Westport: (1) soil moisture monitoring using soil moisture sensors (SM), (2) checkbook method of irrigation scheduling (CB), (3) irrigation management assistant tool (IMA), and (4) EPIC model auto-irrigation (EPIC). Overall, in comparison to the CB method (highest irrigation method), the SM, IMA, and EPIC methods recommended 2.58%, 51.05%, and 9.27% less water in irrigation, respectively. In terms of grain yield, no significant differences were observed between irrigation treatments at the Becker site. The average maize grain yield at the Becker site was 12.02, 11.97, 11.76, and 10.62 Mg/ha, for SM, CB, EPIC, and IMA treatments, respectively. However, in the drier 2021 season, a grain yield loss of 30%, 27%, and 21% was observed under IMA when compared to SM, CB, and EPIC methods, respectively, at the Becker site. At the Westport site, on average, no significant difference in yield was obtained between SM, CB, and EPIC, however, yield under IMA treatment was significantly lower (12%) than CB. The results suggest that nitrate leaching losses can be significantly reduced by altering the rate and frequency of irrigation. IMA treatment resulted in significantly lower nitrate leaching (62%) than the CB method, reducing nitrate leaching from 35.86 kg/ha to 13.71 kg/ha at the Westport site. No significant differences in nitrate leaching were observed at the Becker site because the impact of precipitation superseded the impact of irrigation. Results from this study can aid in the adoption and further development of less labor-intensive and more accurate methods of irrigation scheduling in coarse-textured soils of Great Lakes states. Keywords: Coarse textured soils, Crop evapotranspiration, Irrigation scheduling methods, Maize grain yield, Nitrate-N leaching, Water quality, Water quantity.

Reductions in soil water nitrate beneath a perennial grain crop compared to an annual crop rotation on sandy soil

Nitrate (NO3--N) leaching into groundwater as a result of high nitrogen (N) fertilizer rates to annual crops presents human health risks and high costs associated with water treatment. Leaching is a particularly serious concern on sandy soils overlying porous bedrock. Intermediate wheatgrass (IWG) [Thinopyrum intermedium (Host.) Barkw. & D.R. Dewey], is a perennial grass that is being bred to produce agronomically and economically viable grain, which is commercially available as Kernza®. Intermediate wheatgrass is a low-input crop has the potential to produce profitable grain and biomass yields while reducing NO3--N leaching on sandy soils compared with common annual row crop rotations in the Upper Midwest. We compared grain yields, biomass yields, soil solution NO3--N concentration, soil extractable NO3--N, soil water content, and root biomass under IWG and a conventionally managed corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] rotation for 3 years on a Verndale sandy loam in Central Minnesota. Mean soil solution NO3--N was 77–96% lower under IWG than the annual crop rotation. Soil water content was greater under annuals compared to IWG early in the growing season, suggesting greater water use by IWG during this time. Interactions between crop treatments and depth were observed for soil water content in Year 3. Root biomass from 0 to 60 cm below the soil surface was five times greater beneath IWG compared to soybean, which may explain differences in soil extractable and solution NO3--N among crops. With irrigation on coarse structured soils, IWG grain yields were 854, 434, and 222 kg ha−1 for Years 1–3 and vegetative biomass averaged 4.65 Mg ha−1 yr−1; comparable to other reports on heavier soils in the region. Annual crop grain yields were consistent with local averages. These results confirm that IWG effectively reduces soil solution NO3--N concentrations even on sandy soils, supporting its potential for broader adoption on land vulnerable to NO3--N leaching.

Overwinter survival of Corbicula fluminea in a central Minnesota lake.

Although Corbicula fluminea has been one of the more prolific freshwater invasive species in the world, previous studies have suggested a low probability for overwinter survival in northern latitudes without an artificially created thermal refuge. The discovery of live C. fluminea in a central Minnesota lake absent any known thermal refuge in 2020 presented an opportunity to further evaluate the overwinter survival and population structure of C. fluminea at the presumed edge of their potential range. The population was monitored from December 2020 through September 2021 alongside water temperature to better understand at which temperatures C. fluminea survived and if the population structure suggested reproduction occurring in the lake. We documented live C. fluminea in temperatures as low as 0.3°C. Shell size of recovered individuals suggested multiple cohorts, and the appearance of a new cohort at the end of the study, indicating active reproduction in the lake and suggesting the population had likely been present in the lake for at least two winters by the conclusion of the study period. Our findings provide evidence of the survival below historically documented lower lethal temperature limits and suggests adaptations to modeling predicting suitable habitat, both present and in a changing climate, are necessary to better assess risk of invasion by this species.

Estimating Lake Water Volume With Regression and Machine Learning Methods

The volume of a lake is a crucial component in understanding environmental and hydrologic processes. The State of Minnesota (USA) has tens of thousands of lakes, but only a small fraction has readily available bathymetric information. In this paper we develop and test methods for predicting water volume in the lake-rich region of Central Minnesota. We used three different published regression models for predicting lake volume using available data. The first model utilized lake surface area as the sole independent variable. The second model utilized lake surface area but also included an additional independent variable, the average change in land surface area in a designated buffer area surrounding a lake. The third model also utilized lake surface area but assumed the land surface to be a self-affine surface, thus allowing the surface area-lake volume relationship to be governed by a scale defined by the Hurst coefficient. These models all utilized bathymetric data available for 816 lakes across the region of study. The models explained over 80% of the variation in lake volumes. The sum difference between the total predicted lake volume and known volumes were <2%. We applied these models to predicting lake volumes using available independent variables for over 40,000 lakes within the study region. The total lake volumes for the methods ranged from 1,180,000- and 1,200,000-hectare meters. We also investigated machine learning models for estimating the individual lake volumes and found they achieved comparable and slightly better predictive performance than from the three regression analysis methods. A 15-year time series of satellite data for the study region was used to develop a time series of lake surface areas and those were used, with the first regression model, to calculate individual lake volumes and temporal variation in the total lake volume of the study region. The time series of lake volumes quantified the effect on water volume of a dry period that occurred from 2011 to 2012. These models are important both for estimating lake volume, but also provide critical information for scaling up different ecosystem processes that are sensitive to lake bathymetry.

Reconceptualizing Youth Sparks: A Sociocultural Approach to Co-Designing Programs for Somali Youth

The 4-H Youth Development Program has a long history of fostering positive youth outcomes. Recently, attention and resources have been invested in the development of a program model (i.e., the 4-H Thriving Model) that theorizes the program elements that lead to positive outcomes (Arnold, 2018). Less attention, however, has been given to the program design process by which and with whom 4-H programs are designed and implemented. This matters because a lack of a community-engaged design process may lead to outcomes disconnected from community self-interests or to the exclusion of youth who might view the program as irrelevant to their lives (Simpkins et al., 2017). Drawing from examples of a collaboration between Minnesota 4-H and a Somali youth-serving organization located in central Minnesota, this article discusses how a sociocultural perspective can be used to critique youth programs around the inclusion/exclusion of youths’ broader social, cultural, and political contexts of development and socialization. Particular attention is given to the reconceptualization of sparks as socially situated, collective, and relational. The article concludes with a discussion of practical implications and future directions for Extension/4-H’s community-engaged and ongoing program design processes.

Double-cropping oilseed sunflower after winter camelina

Double-cropping as a means of sustainably intensifying oilseed production could promote farmer adoption of new and alternative use oil crops like camelina [Camelina sativa (L.) Crantz]. Previous research indicated that double-cropping sunflower (Helianthus annuus L.) after winter camelina in the upper Midwest USA tended to reduce sunflower seed yield and oil content as compared with monocrop sunflower. However, new semidwarf hybrid sunflower genotypes with early maturity may be better suited for developing double-cropping systems for oil production in the upper Midwest and northern Great Plains. To evaluate seed and oil yields of winter camelina (cv. Joelle) and double-cropped sunflower compared with monocrop sunflower, a field study was conducted across two growing seasons (2017–2019) in west central Minnesota USA. One early maturing semidwarf oil sunflower hybrid, Honeycomb NS, and three common commercial full season oil hybrids were evaluated. Additionally, soil moisture to a 1-m depth was monitored during both growing seasons, which did not appear to limit production of the two crops in a single season at the study site. Although delayed sowing associated with double-cropping generally reduced sunflower seed yield, oil content, and the oleic/linoleic acid ratio compared with monocrop controls, these decreases were less for the early maturing hybrid Honeycomb NS. During one season of the study, total oil yield (winter camelina + sunflower) of double-cropped Honeycomb NS was 1.5 times greater than its monocrop counterpart. In addition to sustainably intensifying oil production, double-cropping sunflower with winter camelina might appeal to producers wanting to reduce the risk of one or the other crop failing in any given year. Nevertheless, double-cropping in the upper Midwest USA can be risky due to year-to-year variations in weather and length of growing season.

An experiential model of drought risk and future irrigation behaviors among central Minnesota farmers

An experiential model of drought risk and future irrigation behaviors among central Minnesota farmers

High‐Resolution Climate Projections Over Minnesota for the 21st Century

AbstractMinnesota is the state with the strongest winter warming in the contiguous United States. We performed regional climate projections at 10 km horizontal resolution using the Weather Research Forecasting model forced with eight CMIP5 GCMs. The selected GCMs have previously been found to be in relatively good agreement with observations over Minnesota compared to other members of the CMIP5 model ensemble. Our projections suggest ongoing warming in all seasons, especially in winter, as well as shallower snow depth and fewer days with snow cover. We expect significant increases in spring and early summer heavy precipitation events. Our comparisons between different time slices and two different emission scenarios indicate a climate for the state of Minnesota near the end of the 21st century that is significantly different from what has been observed by the end of the 20th century. Winters and summers are expected to be up to 6 and 4°C warmer, respectively, over northern and central Minnesota, and spring precipitation may increase by more than 1 mm d−1 over northern Minnesota. Especially over the central part of the state, winter snow depth is projected to decrease by more than 12 cm, and the number of days per year with snow depth of more than 2.54 cm (one inch) is expected to decrease by up to 55.

Abstract 13415: Initial Diuretic Dosing and Length of Stay in Patients Hospitalized for Congestive Heart Failure

Background: Among patients hospitalized for heart failure, a prior randomized trial suggests the initial dose of diuretics may have implications on time to decongestion and length of hospital stay. Little is known about the dosing of intravenous loop diuretics in routine clinical practice and the association between diuretic dosing and hospital length of stay. Methods: We identified 12,209 patients admitted with heart failure at 12 Allina Health hospitals in central Minnesota and western Wisconsin between January 1, 2017 and December 31, 2020. We excluded patients on observational status, no or unknown home loop diuretic dosing, no intravenous loop diuretic within 24 hours of admission, and patients who received inotropes or dialysis within 24 hours of admission. Initial diuretic dose was compared to home dose in furosemide equivalents using the Diuretic Strategies in Patients with Acute Decompensated Heart Failure trial logic and categorized into below home dose, equivalent to home dose, or above home dose. We describe patient characteristics and length of stay by category of initial diuretic dose. Results: Among 3,580 admitted for heart failure, initial diuretic dose was below home dose in 555 (15%) patients, equivalent to home dose in 756 (21%) patients, and above home dose in 2269 (64%) patients. Baseline characteristics by category of initial diuretic dose are presented in the Table. Mean length of stay was longest in patients receiving a diuretic dose that was below home dose (6.4 days) and shortest in patients receiving a dose above home equivalent (5.0 days) (Table). Conclusions: In a cohort of patients admitted for heart failure, more than 1 in 3 patients received an initial dose of intravenous loop diuretics that was equivalent to or below their home diuretic dose and this was associated with a longer length of hospital stay. These findings may represent a quality improvement opportunity in the care of patients hospitalized for heart failure.

Optimizing the location of watercraft inspection stations to slow the spread of aquatic invasive species

The accidental spread of aquatic invasive species (AIS) by recreational boaters is a major concern of state and county environmental planners in the USA. While programs for watercraft inspection to educate boaters and slow AIS spread are common practice, large numbers of boats and waterbodies, together with limited budgets, make program design difficult. To facilitate program design, we developed an integer programming model for allocation of scarce inspection resources among lakes. Our model uses species-specific infestation status of lakes and estimates of boat movement between lakes. The objective is to select lakes for inspection stations to maximize the number of risky boats inspected, where risky boats are ones that move from infested to uninfested lakes. We apply our model in Stearns County in central Minnesota, USA, to prioritize lakes for inspection stations and evaluate alternative management objectives. With an objective of protecting uninfested lakes within and outside Stearns County, the optimal policy is to locate stations at infested lakes having the most boats departing for uninfested lakes inside and outside the county. With an objective of protecting only Stearns County lakes, the optimal policy is to locate stations at both infested and uninfested lakes having the riskiest boats arriving from within and outside the county and departing to in-county lakes. The tradeoff between these objectives is significant.