Southern Minnesota Research Articles

Predicting changes in yield and water use in the production of corn in the United States under climate change scenarios

Changes in climate will have significant implications for agricultural production in the United States. Increased temperatures, as well as altered hydrologic cycles, will result in changes to corn production, a major food staple in the United States. The objective of this study was to use the CERES-Maize model to evaluate potential changes in corn yield and water use under 2050 climate scenarios in the USDA-Economic Research Service (ERS) Heartland Region of the United States. CERES-Maize was used to simulate corn physiology and yields using weather data for three future climate scenarios generated by the ECHAM5 climate change models. The projected physiology and yield results were then compared to baseline conditions from the years 1997 through 2007. Throughout all future climate scenarios the number of days to corn silking and maturity were decreased under both rainfed and irrigated scenarios. Overall, the CERES-Maize model predicted increased total yields for the ERS-Heartland Region. However, large regional variability was observed throughout the Heartland Region, with yield simulations for the eastern production areas, including Ohio, Illinois, and Missouri, as well as southern Minnesota resulting in predicted declines in corn yields.

Reach-scale stream restoration in agricultural streams of southern Minnesota alters structural and functional responses of macroinvertebrates

Recent studies suggest that stream restoration at the reach scale may not increase stream biodiversity, raising concerns about the utility of this conservation practice. We examined whether reach-scale restoration in disturbed agricultural streams was associated with changes in macroinvertebrate community structure (total macroinvertebrate taxon richness, total macroinvertebrate density, Ephemeroptera, Plecoptera, Trichoptera [EPT] taxon richness, % abundance of EPT taxa) or secondary production (macroinvertebrate biomass over time). We collected macroinvertebrate samples over the course of 1 y from restored and unrestored reaches of 3 streams in southern Minnesota and used generalized least-square (GLS) models to assess whether measures of community structure were related to reach type, stream site, or sampling month. After accounting for effects of stream site and time, we found no significant difference in total taxon richness or % abundance of EPT taxa between restored and unrestored reaches. However, the number of EPT taxa and macroinvertebrate density were significantly higher in restored than in unrestored reaches. We compared secondary production estimates among study reaches based on 95th-percentile confidence intervals generated via bootstrapping. In each study stream, secondary production was significantly (2–3×) higher in the restored than in the unrestored reach. Higher productivity in the restored reaches was largely a result of the disproportionate success of a few dominant, tolerant taxa. Our findings suggest that reach-scale restoration may have ecological effects that are not detected by measures of total taxon richness alone.

Little War on the Prairie: an auto-critique

Using RadioDoc Review’s suggested criteria for evaluating a radio documentary, John Biewen delivers an auto-critique of his own program, Little War on the Prairie. It tells the story of the U.S.-Dakota War, a bloody Plains Indian war that broke out in the summer of 1862 in southern Minnesota. That six-week conflict took the lives of hundreds of people, perhaps a thousand, a larger death toll than in the better-known bloodlettings at Little Big Horn or Wounded Knee. Most of the dead were white settlers, though the U.S. government’s reprisals in the aftermath of the war killed up to several thousand Dakota Indians. A grim highlight of that payback was the simultaneous hanging of thirty-eight Dakota warriors, the largest mass execution in U.S. history, on the day after Christmas, 1862, in Mankato, Minnesota. Which happens to be Biewen’s hometown. Yet the story was not well known there – and Biewen seeks to find out why. Little War on the Prairie aired on This American Life (2012), whose host, Ira Glass, was also its primary editor. Download full article with audio link embedded.

Developing optimum subsurface drainage design procedures

The DRAINMOD simulation model was used to investigate combinations of drain depth and spacing for major soils of southern Minnesota to maximize profitability and minimize drained volume and surface runoff. Six soil types (Canisteo, Harps, Nicollet, Normania, Okoboji, and Webster) and three locations (Lamberton, Waseca, and Willmar) were included in the original study and one soil-location combination was reported on, herein (Webster–Waseca). Four drain depths (90, 105, 120, and 135 cm) were used and drain spacings were selected to simulate drainage coefficients from 3.2 to 19 mm/day. Soil input files for DRAINMOD were created using a combination of measured data from field sampling (soil texture and bulk density), data estimated with the Rosetta soil parameter model/van Genuchten equation (water retention curves), and publicly available data (soil permeability). Long-term simulations were conducted for each location using 90 years of historical climate data (1915–2005). Outputs from DRAINMOD were used to create “performance” indices that enable the concurrent consideration of profitability, drainage volumes, and surface runoff, when choosing drain depth and spacing. A spreadsheet design tool was developed to compute and display these indices, based on a few simple user inputs to define cost and crop price. Internal rate of return was used as the basis for profitability considerations. Results obtained indicated that in general, profitability may be increased with increased drain depth and spacing, due to system costs associated with narrower drain spacings. It was found that when considering both profitability and drainage volume, deeper, more widely spaced drainage systems were generally preferable, because of increased profitability and decreased drainage volumes.

Optimizing nitrogen rates in the midwestern United States for maximum ecosystem value

The importance of corn production to the midwestern United States cannot be overestimated. However, high production requires high nitrogen fertilization, which carries costs to environmental services such as water quality. Therefore, a trade-off exists between the production of corn yield and water quality. We used the Groundwater Vulnerability Assessment for Shallow depths and Crop Environment Resource Synthesis-Maize models to investigate the nature of this trade-off while testing the Simple Analytic Framework trade-offs featured in this Special Feature. First, we estimated the current levels of yield and water quality production in northeastern Iowa and southern Minnesota at the 1-square-kilometer, county, and regional scales. We then constructed an efficiency frontier from optimized nitrogen application patterns to maximize the production of both yield and water quality. Results highlight the context dependency of this trade-off, but show room for increasing the production of both services to the benefit of all stakeholders. We discuss these results in the context of spatial scale, biophysical limitations to the production of services, and stakeholder outcomes given disparate power balances and biophysical contexts.

Patterns of Selective Herbivory on Five Prairie Legume Species

Abstract Historic, wide-spread destruction of native prairies in Minnesota was caused by conversion to agricultural land, disruption of disturbance regimes, and loss of key species. Attempts to restore tall-grass prairies have resulted in a new ecosystem type on the Midwestern landscape, with novel assemblages of both plant and animal species. The mammalian herbivore community, once dominated by bison, is now primarily comprised of white-tailed deer (Odocoileus virginianus), Eastern cottontail rabbits (Sylvilagus floridanus), and small mammals such as meadow voles (Microtus pennsylvanicus). The role of this assemblage of herbivores in restored prairies is not well understood. This study characterizes patterns of mammalian herbivory on five legume species in restored prairie in southern Minnesota. Legumes were sampled along transects that varied in their distance from the prairie-forest boundary and time since prescribed burning. Herbivore selectivity was determined for each legume species using an electiv...

Genetic variation in the mitochondrial 16S ribosomal RNA gene of Ixodes scapularis (Acari: Ixodidae).

BackgroundIxodes scapularis is a vector of several human pathogens in the United States, and there is geographical variation in the relative number of persons infected with these pathogens. Geographically isolated populations of I. scapularis have established or are in the process of establishing in southern Canada. Knowledge of the genetic variation within and among these populations may provide insight into their geographical origins in the United States and the potential risk of exposure of Canadians to the different pathogens carried by I. scapularis.MethodsPart of the mitochondrial (mt) 16S ribosomal (r) RNA gene was amplified by PCR from 582 ticks collected from southern Canada, and Minnesota and Rhode Island in the United States. Sequence variation was examined in relation to the predicted secondary structure of the gene. Genetic diversity among populations was also determined.ResultsDNA sequence analyses revealed 52 haplotypes. Most mutational alterations in DNA sequence occurred at unpaired sites or represented partial compensatory base pair changes that maintained the stability of the secondary structure. Significant genetic variation was detected within and among populations in different geographical regions. A greater proportion of the haplotypes of I. scapularis from the Canadian Prairie Provinces were found in the Midwest of the United States than in other regions, whereas more of the haplotypes of I. scapularis from the Canadian Central and Atlantic Provinces occurred in the Northeast of the United States. Nonetheless, 58% of I. scapularis were of a haplotype that occurs in the Midwest and Northeast of the United States; thus, their geographical origins could not be determined.ConclusionsThere is considerable genetic variation in the mt 16S rRNA gene of I. scapularis. There is some evidence to support the hypothesis that some lineages of I. scapularis in the Atlantic and Central Provinces of Canada may be derived from colonizing individuals originating in the Northeast of the United States, whereas those in the Prairie Provinces may be derived from individuals originating in the Midwest of the United States. However, additional genetic markers are needed to test hypotheses concerning the geographical origins of I. scapularis in Canada.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-014-0530-6) contains supplementary material, which is available to authorized users.

Protocol and Interactive Routine forthe Design of Subsurface Bioreactors

Abstract. One potential practice to reduce nitrate and phosphate transfer from subsurface (tile)-drained farmlands is the use of fixed-bed, in-field subsurface bioreactors. These bioreactors are trenches filled with carbon material (usually wood chips), which serve as a medium for denitrifying bacteria to grow, thus reducing the amount of nitrate that enters water bodies from tile drains. If a bioreactor is undersized, water will not be detained long enough for denitrification to occur, or much of the water will bypass the system. On the other hand, if it is oversized, extreme reducing conditions can result in the formation of deleterious compounds. In this article, we propose a new protocol for optimizing the size of a bioreactor, describe an interactive routine in which this protocol has been implemented, and present the application of the routine to the design of a bioreactor in southern Minnesota. The routine is available in the online version of the Illinois Drainage Guide.

Using LiDAR and geographic information system data to identify optimal sites in southern Minnesota for constructed wetlands to intercept nonpoint source nitrogen

N itrate (NO3) carried in drainage from midwestern crop lands impairs local waters and makes a significant contribution to hypoxia in the Gulf of Mexico (Brezonik et al. 1999; Nangia et al. 2008). Conservation practices are being promoted in the Midwest to remedy water quality. Among them, improved farming practices such as reduced fertilizer use, constructed (either created or restored) wetlands, and riparian buffers are the three principal approaches for remedying Gulf of Mexico hypoxia (Mitsch et al. 2001; Randall and Mulla 2001; Mitsch and Gosselink 2007a). A constructed wetland was defined by Hammer and Bastian (1989) as “a designed and man-made complex of saturated substrate, emergent and submergent vegetation, animal life, and water that simulates natural wetlands for human use and benefits.” The microbial populations at the plant roots can transform nutrients and metallic ions and compounds; this makes wetlands effective at treating runoff from municipal, mining, and agricultural sources (Haan et al. 1994). Wetlands were once widely distributed in the Midwest, and many of them were drained for crop production. Therefore, the midwestern geomorphology and soils are favorable for wetland restoration. Wetland construction can control the growing problem of reactive nitrogen (N), primarily NO3, in the aquatic environment (Hey…

Northern Saw-whet Owl: regional patterns for fall migration and demographics revealed by banding data

We describe attributes of Northern Saw-whet Owls (Aegolius acadicus) during fall migration using 167,774 records from the U.S. Bird Banding Laboratory for central and eastern North America from 1929–2010. We describe movement among 18 geographic regions using records of 1,444 birds captured and recaptured between 1 September and 31 December of the same year. These data show little exchange between western Lake Superior and eastern North America. The direction of movement within a region was strongly influenced by large water bodies, varied greatly among regions, and showed high dispersal in the absence of shorelines of large water bodies. We used recent banding data to analyze population demographics from northwestern Minnesota to the coast of Maine in the north, and from southern Minnesota and southern Wisconsin to southern Appalachia and the mid-Atlantic coastal region in eastern United States. The weighted mean proportion of Hatch Year (HY) birds declined significantly from 63% in northwestern Minnesota to 42% in southern Minnesota/southern Wisconsin and from 70% in northern Ontario to 48% in southern Appalachia. Annual variation in the proportion of HY birds showed little correlation between eastern and central origin sites but moderate correlation within each of these regions. We define irruptions as years when the proportion of HY birds is 15% or greater than the weighted mean for each site, a level that occurs once in 4 years on average but at irregular intervals. We determined a very high correlation between the proportion of HY birds banded in northeast of Lake Ontario and the abundance of small mammals, suggesting a close relationship between food supply and reproductive success.

Medical humanitarianism in the United States: Alternative healthcare, spirituality and political advocacy in the case of Our Lady Guadalupe Free Clinic

Exclusionary practices in dominant market-based systems are recognized as contributing to global health inequities. Undocumented immigrants are particularly vulnerable to unequal access to healthcare. Humanitarian NGOs strive to respond meaningfully to these health inequities among migrants and undocumented immigrants. Few studies describe the work of humanitarian NGOs that advocate for the right to health of undocumented immigrants in high-income countries. This paper discusses immigration, health, and human rights while examining solidarity, spirituality, and advocacy using a U.S.-based example of medical humanitarianism: the ‘Our Lady of Guadalupe Free Clinic.’ In 2011, the Free Clinic began in the basement of a Catholic parish in Minnesota in response to the lack of access to medical services for undocumented immigrants. Run by a local grassroots organization, it is held every six weeks and offers free primary healthcare to Latino immigrants and the uninsured. In this article, we examine the tricky relationship between humanitarianism and human rights in the U.S. Using ethnography, we draw on participant observation and interviews with 30 clinic volunteers, including health professionals, administrators, language interpreters, and spiritual leaders. The study was conducted September 2012–December 2013 in southern Minnesota. We examine how notions of solidarity, spirituality, and advocacy structure faith-based medical humanitarianism in the U.S. and explore the underlying tensions between the humanitarian mandate, spiritual teachings (social justice, solidarity), and political advocacy. Examining a moment of “crisis” in the Clinic, our study shows that volunteers experience the alliance between spirituality and advocacy with uneasiness. While a spiritual calling may initially motivate volunteers to serve, an embrace of human rights advocacy is important in a sustained effort to provide humanitarian medical care to individuals who fall outside of the political and moral community in the U.S.

The Nature of Ethical Conflicts and the Meaning of Moral Community in Oncology Practice

To explore ethical conflicts in oncology practice and the nature of healthcare contexts in which ethical conflicts can be averted or mitigated. Ethnography. Medical centers and community hospitals with inpatient and outpatient oncology units in southern California and Minnesota. 30 oncology nurses, 6 ethicists, 4 nurse administrators, and 2 oncologists. 30 nurses participated in six focus groups that were conducted using a semistructured interview guide. Twelve key informants were individually interviewed. Coding, sorting, and constant comparison were used to reveal themes. Most ethical conflicts pertained to complex end-of-life situations. Three factors were associated with ethical conflicts: delaying or avoiding difficult conversations, feeling torn between competing obligations, and the silencing of different moral perspectives. Moral communities were characterized by respectful team relationships, timely communication, ethics-minded leadership, readily available ethics resources, and provider awareness and willingness to use ethics resources. Moral disagreements are expected to occur in complex clinical practice. However, when they progress to ethical conflicts, care becomes more complicated and often places seriously ill patients at the epicenter. Practice environments as moral communities could foster comfortable dialogue about moral differences and prevent or mitigate ethical conflicts and the moral distress that frequently follows.

The Impact of Corn Stover Removal on N2O Emission and Soil Respiration: an Investigation with Automated Chambers

Corn stover removal, whether for silage, bedding, or bioenergy production, could have a variety of environmental consequences through its effect on soil processes, particularly N2O production and soil respiration. Because these effects may be episodic in nature, weekly snapshots with static chambers may not provide a complete picture. We adapted commercially available automated soil respiration chambers by incorporating a portable N2O analyzer, allowing us to measure both CO2 and N2O fluxes on an hourly basis through two growing seasons in a corn field in southern Minnesota, from spring 2010 to spring 2012. This site was part of a USDA multilocation research project for five growing seasons, 2008–2012, with three levels of stover removal: zero, full, and intermediate. Initially in spring 2010, two chambers were placed in each of the treatments, but following planting in 2011, the configuration was changed, with four chambers installed on zero removal plots and four on full removal plots. The cumulative data revealed no significant difference in N2O emission as a function of stover removal. CO2 loss from the full removal plots was slightly lower than that from the zero removal plots, but the difference between treatments was much smaller than the amount of C removed in the residue, implying loss of soil carbon from the full removal plots. This is consistent with soil sampling data, which showed that in five of six sampled blocks, the SOC change in the full removal treatments was negative relative to the zero removal plots. We conclude that (a) full stover removal may have little impact on N2O production, and (b) while it will reduce soil CO2 production, the reduction will not be commensurate with the decrease in fresh carbon inputs and, thus, will result in SOC loss.

Angel Investment and Collective Agricultural Marketing: The Case of the Minnesota Food Network

AbstractThe Minnesota Food Network is a limited liability company comprised of 52 farmers producing a variety of high‐quality, sustainably produced agricultural products in southern Minnesota. The network's goal is to develop a regional food system to provide locally grown food at a price that “is fair” to both consumers and producers. This case outlines the challenges that the network faces in their efforts to expand to take advantage of a market opportunity. One of their biggest challenges is that they face high operating costs because of their disaggregated distribution system and need to purchase a distribution and storage facility and two vehicles. They will fund the purchase of a building through an angel investor. An angel investor is necessary because the network cannot sustain traditional loan payments in its current form. Students are asked to consider a number of questions pertaining to the decisions in this case outlined in the final section of the case study.

Understanding the Long-Term Benefits of a Latino Financial Literacy Education Program

The long-term impact of a Latino financial literacy program was evaluated with a sample of relatively recent immigrant populations in southern Minnesota. Telephone and face-to-face interviews were conducted with participants 6 months post program completion. Results indicate that improvements in knowledge and skills were retained and that these learning were applied to make improvements in participants' financial situations. Participants acknowledged that more important than gaining knowledge was learning how to apply what they have learned. Implications for Extension are offered in terms of those factors that promoted the effectiveness of the financial literacy education.

Geospatial and Temporal Analysis of a 20‐Year Record of Landsat‐Based Water Clarity in Minnesota's 10,000 Lakes

AbstractA large 20‐year database on water clarity for all Minnesota lakes ≥8 ha was analyzed statistically for spatial distributions, temporal trends, and relationships with in‐lake and watershed factors that potentially affect lake clarity. The database includes Landsat‐based water clarity estimates expressed in terms of Secchi depth (SDLandsat), an integrative measure of water quality, for more than 10,500 lakes for time periods centered around 1985, 1990, 1995, 2000, and 2005. Minnesota lake clarity is lower (more turbid) in the south and southwest and clearer in the north and northeast; this pattern is evident at the levels of individual lakes and ecoregions. Temporal trends in clarity were detected in ~11% of the lakes: 4.6% had improving clarity and 6.2% had decreasing clarity. Ecoregions in southern and western Minnesota, where agriculture is the predominant land use, had higher percentages of lakes with decreasing clarity than the rest of the state, and small and shallow lakes had higher percentages of decreasing clarity trends than large and deep lakes. The mean SDLandsat statewide remained stable from 1985 to 2005 but decreased in ecoregions dominated by agricultural land use. Deep lakes had higher clarity than shallow lakes statewide and for lakes grouped by land cover. SDLandsat decreased as the percentage of agriculture and/or urban area increased at county and catchment levels and it increased with increasing forested land.

Evaluation of the hooghoudt and kirkham tile drain equations in the soil and water assessment tool to simulate tile flow and nitrate-nitrogen.

Subsurface tile drains in agricultural systems of the midwestern United States are a major contributor of nitrate-N (NO-N) loadings to hypoxic conditions in the Gulf of Mexico. Hydrologic and water quality models, such as the Soil and Water Assessment Tool, are widely used to simulate tile drainage systems. The Hooghoudt and Kirkham tile drain equations in the Soil and Water Assessment Tool have not been rigorously tested for predicting tile flow and the corresponding NO-N losses. In this study, long-term (1983-1996) monitoring plot data from southern Minnesota were used to evaluate the SWAT version 2009 revision 531 (hereafter referred to as SWAT) model for accurately estimating subsurface tile drain flows and associated NO-N losses. A retention parameter adjustment factor was incorporated to account for the effects of tile drainage and slope changes on the computation of surface runoff using the curve number method (hereafter referred to as Revised SWAT). The SWAT and Revised SWAT models were calibrated and validated for tile flow and associated NO-N losses. Results indicated that, on average, Revised SWAT predicted monthly tile flow and associated NO-N losses better than SWAT by 48 and 28%, respectively. For the calibration period, the Revised SWAT model simulated tile flow and NO-N losses within 4 and 1% of the observed data, respectively. For the validation period, it simulated tile flow and NO-N losses within 8 and 2%, respectively, of the observed values. Therefore, the Revised SWAT model is expected to provide more accurate simulation of the effectiveness of tile drainage and NO-N management practices.

Agronomic Responses of Continuous Corn to Stover, Tillage, and Nitrogen Management

Corn (Zea mays L.) stover removal for biofuel production is expected to increase in the near future. Previous research suggests stover removal is best suited to continuous corn (CC) cropping systems with reduced tillage. However, grain yields in reduced tillage CC systems in the Upper Midwest can be reduced because of cool soil temperatures restricting early‐season growth. Field experiments were conducted over 3 yr at two locations in southern Minnesota with medium‐ and fine‐textured soils to assess the agronomic responses of CC to stover removal, tillage system, and fertilizer N rate. Stover removal and/or tillage increased soil temperature by as much as 4°C, and differences among treatments generally existed until canopy closure. Corn emergence was 6% greater with stover removal in no‐tillage (NT), but was not affected by stover removal in chisel‐tillage (CT) and strip‐tillage (ST). Stover removal increased normalized difference vegetative index (NDVI) at the eight leaf collar stage (V8) by 20 and 13% in NT and ST, respectively, but had no effect on NDVI in CT. Stover removal decreased the economically optimum N rate (EONR) by >12 and >19 kg N ha–1 in NT and ST, respectively, and increased grain yield at the EONR by 7, 9, and 6% in CT, NT, and ST, respectively. These results indicate stover removal can improve short‐term agronomic productivity of moderate‐ to high‐yielding CC on productive soils in the Upper Midwest.

Modeling the impact of nitrogen fertilizer application and tile drain configuration on nitrate leaching using SWAT

Recently, the Soil and Water Assessment Tool (SWAT) was revised to improve the partitioning of runoff and tile drainage in poorly drained soils by modifying the algorithm that computes the soil moisture retention parameter. In this study, the Revised SWAT model was used to evaluate the sensitivity and long-term effects of different nitrogen (N) application rates and tile drain spacing (SDRAIN) and depths (DDRAIN) on nitrate-nitrogen (NO3-N) losses through tile drains. Monitoring data for the 1983–1996 period measured on three experimental plots on a poorly drained Webster clay loam soil (fine-loamy, mixed, superactive, mesic Typic Endoaquoll) in southern Minnesota was used. Sensitivity analysis covered the 1983–1996 period and long-term simulations were made for the 1915–1996 period. Sensitivity analysis showed a decrease in tile flow as DDRAIN decreased and/or SDRAIN increased. The predicted NO3-N losses in tile drain decreased by 16% (from 33.8 to 28.4kgha−1) and 14% (from 34.0 to 29.4kgha−1) when SDRAIN was increased by 122% (from 27 to 60m) and 40% (from 1.5 to 0.9m), respectively. However, NO3-N losses were decreased by 67% (from 33.8 to 11.1kgha−1) when N application rate was decreased by 50% (from 200 to 100kgha−1). Long-term simulations results indicated that much greater reductions in NO3-N losses can be achieved with reduction in the N application rates than with changing the tile drain spacing and depth. Reductions in NO3-N losses were consistent with the results reported using the Agricultural Drainage and Pesticide Transport (ADAPT) model, which was developed specifically for understanding effects of tile drainage on water quality in the Upper Midwest U.S. Overall, results from sensitivity analysis and long term simulation indicated that Revised SWAT can be used to adequately evaluate the effects of tile drain configurations on drainage and associated NO3-N losses.

Impacts of Hydrologic Change on Sandbar Nesting Availability for Riverine Turtles in Eastern Minnesota, USA

There have been significant increases in stream flow in many rivers of the Upper Midwestern United States since 1980. Increased summer flows may negatively impact ecological processes, including aquatic organisms’ life cycles. The smooth softshell (Apalone mutica) and wood turtle (Glyptemys insculpta) are threatened by alteration of stream flow regime and other changes to river ecosystems in the Upper Midwest. We hypothesized that prolonged duration of high summer flows would reduce time available for nesting. We assessed hydrologic change using the Indicators of Hydrologic Alteration program and stream gauge data, characterized physical properties of sandbars, surveyed turtle nesting sites and assessed historical channel change using aerial photos in GIS on five Upper Midwest rivers. A river stage-sandbar area relationship was developed to determine the effect of prolonged summer flow duration on turtle nesting opportunity for the 1940–2009 time period. Suitable water levels have declined since 1980 in the agricultural watersheds of southern Minnesota likely delaying hatching and reducing survival, particularly for aquatic turtles such as A. mutica. In contrast to the agricultural watersheds, there was no significant change in the northern forested rivers’ stream flow and sandbar availability during the nesting season. Management to reduce summer stream flow in agricultural watersheds and protection of known nest sites could benefit threatened aquatic turtle populations.