Northwestern United States Research Articles

Hundred year projected carbon loads and species compositions for four National Forests in the northwestern USA

BackgroundForests are an important component of the global carbon balance, and climate sensitive growth and yield models are an essential tool when predicting future forest conditions. In this study, we used the dynamic climate capability of the Forest Vegetation Simulator (FVS) to simulate future (100 year) forest conditions on four National Forests in the northwestern USA: Payette National Forest (NF), Ochoco NF, Gifford Pinchot NF, and Siuslaw NF. Using Forest Inventory and Analysis field plots, aboveground carbon estimates and species compositions were simulated with Climate-FVS for the period between 2016 and 2116 under a no climate change scenario and a future climate scenario. We included a sensitivity analysis that varied calculated disturbance probabilities and the dClim rule, which is one method used by Climate-FVS to introduce climate-related mortality. The dClim rule initiates mortality when the predicted climate change at a site is greater than the change in climate associated with a predetermined shift in elevation.ResultsResults of the simulations indicated the dClim rule influenced future carbon projections more than estimates of disturbance probability. Future aboveground carbon estimates increased and species composition remained stable under the no climate change scenario. The future climate scenario we tested resulted in less carbon at the end of the projections compared to the no climate change scenarios for all cases except when the dClim rule was disengaged on the Payette NF. Under the climate change scenario, species compositions shifted to climatically adapted species or early successional species.ConclusionThis research highlights the need to consider climate projections in long-term planning or future forest conditions may be unexpected. Forest managers and planners could perform similar simulations and use the results as a planning tool when analyzing climate change effects at the National Forest level.

Hop (Humulus lupulus L.) terroir has large effect on a glycosylated green leaf volatile but not on other aroma glycosides

Genetics and environment both influence the content of hop (Humulus lupulus L.) aroma compounds. The effects of these two factors on aroma glycosides, which can change the aroma profile of beer over time, were examined in a preliminary study. Twenty-three hop cultivars were grown in the northwestern United States in two locations with distinct terroirs. UPLC–MS/MS analysis of hop cone extracts revealed that growing location had a large effect on hexyl glucoside levels but only a negligible effect on levels of linalyl, raspberry ketone, and 2-phenylethyl glucoside, which were mostly affected by genetic differences. The large terroir effect on hexyl glucoside, which releases a green leaf volatile with a grassy aroma when hydrolyzed, but not on the other aroma glucosides, which have more desirable aromas when hydrolyzed, could have an impact on beer aroma profiles.

Predicting April Precipitation in the Northwestern United States Based on Arctic Stratospheric Ozone and Local Circulation

Using observations and reanalysis, we develop a linear regression model to predict April precipitation in the northwestern United States (PNWUS) with a one-month lead. Not only this model reproduces April PNWUS for the training period, but also its predictions are robust and reliable for the independent test period. Two independent factors, Arctic stratospheric ozone (ASO) and potential height in western North America at 700 hPa (H700WNA), are used to construct the linear regression model. Based on observations, possible mechanisms of ASO and H700WNA affecting PNWUS are that: April circulation anomalies over the North Pacific related to March ASO changes can extend eastward to the western United States, causing April PNWUS anomalies. When the April H700WNA is abnormally high, there will be an anti-cyclonic circulation anomaly over the northwestern United States, which not only inhibits water-vapor transport from the North Pacific to the northwestern United States but also suppresses convective activity. This process also influences the April PNWUS. A transient experiment using a climate model with a longer period also agrees with above result from observations. Using the predicted April H700WNA from the climate forecast system (CFS) of the National Centers for Environmental Prediction (NCEP) based on March data and the observed March ASO, the April PNWUS predicted by this statistical model is closer to observations than the April PNWUS predicted directly by the CFS using March data.

The impacts of transported wildfire smoke aerosols on surface air quality in New York State: A case study in summer 2018

Abstract Wildfire smoke aerosols, once emitted, can transport over long distances and affect surface air quality in downwind regions. In New York State (NYS), fine particulate matter (PM2.5) concentration continues to decrease due to anthropogenic emission reductions and regulatory initiatives in recent years. Smoke aerosols, however, are projected to increase, making them the dominant source of PM2.5. Thus, the influences of smoke aerosols could become more important in the future. In this study, the long-range transport of smoke aerosols, and their impacts on local air quality over NYS in mid-August 2018 were investigated using satellite measurements, ground-based networks, and model products. Satellite measurements showed extensive fire activities over the northwestern United States (US) during August 8th – 10th. Air quality monitoring sites in NYS reported a threefold increase in average PM2.5 concentration (from 8.4 ± 3.4 μg m−3 to 24.8 ± 4.0 μg m−3) on August 15th – 16th, while the ground-based profiler network detected aerosol layers at 2–5 km across the state. Analysis of backward trajectories revealed that the plumes originated from wildfires, transported through southern Canada and arrived at the east coast during a period of 5–7 days. The increased PM2.5 in NYS can be attributed to boundary layer entrainment and vertical mixing of the aloft transported smoke aerosols down to the surface. The NYS mesoscale weather network (NYSM), which is originally designed for severe weather monitoring, demonstrate the capability to probe the lower atmosphere and provide the vertical extent information of air pollutants.

The invertebrate host of salmonid fish parasites Ceratonova shasta andParvicapsula minibicornis (Cnidaria: Myxozoa), is a novel fabriciid annelid, Manayunkia occidentalis sp. nov. (Sabellida: Fabriciidae).

Myxosporea (Cnidaria: Myxozoa) are common fish parasites with complex life cycles that involve annelid hosts. Two economically important salmonid-infecting myxosporeans from rivers of the northwestern United States, Ceratonova shasta (Noble, 1950) and Parvicapsula minibicornis Kent et al., 1997, have life cycles that require a freshwater annelid host, identified previously as Manayunkia speciosa Leidy, 1859. This species was described originally from Pennsylvania, with subsequent records from New Jersey, the Great Lakes and west coast river basins. Despite apparent widespread distributions of both suitable fish hosts and the nominal annelid host, both parasites are restricted to river basins in the northwestern US and have never been recorded from the Great Lakes or the eastern US. In this study, we sampled 94 infected and uninfected annelids from two northwestern US rivers to confirm the identity of the host. We found these new specimens had mitochondrial COI sequences with no more than 4.5% distance from each other, but with at least 11% divergence from M. speciosa sampled from near the type locality (New Jersey) and Lake Superior. We did not recover any M. speciosa from either west coast river. The annelid from the Klamath and Willamette rivers showed marked sexual dimorphism that has not been reported in any Manayunkia described to date, though it is apparent that this had been missed in M. speciosa. Accordingly, we describe a new taxon, Manayunkia occidentalis sp. nov., and show that it can host both C. shasta and P. minibicornis. We suspect that previous records of Manayunkia from Pacific Northwest watersheds are likely to be M. occidentalis sp. nov. and not M. speciosa. Sampling of Manayunkia from additional localities is underway to test if the novel Manayunkia species is the only freshwater fabriciid annelid present across the Pacific Northwest.

Multiple insecticide resistance in onion thrips populations from Western USA

Thrips tabaci is a key pest of onions, especially in the Pacific Northwestern USA. Management of T. tabaci is dominated by the application of various insecticides. However, T. tabaci is known to develop insecticide resistance which possibly leads to control failures, crop loss, and environmental concern. Here, we evaluated resistance status of T. tabaci populations from conventional and organic commercial onion fields to three widely used insecticides: oxamyl, methomyl, and abamectin with on-field concentration-mortality bioassays. The biochemistry and molecular mechanisms underlying resistance to these insecticides were also investigated by using enzymatic assays and detecting resistance-associated mutations. Field-evolved resistance to oxamyl, methomyl and abamectin were detected in most of the T. tabaci populations collected from conventional onion farms. At the labeled field rate, all the tested insecticides, particularly methomyl and oxamyl, had significantly reduced efficacy. Enzymatic assays of insecticide target and detoxification enzymes indicated that T. tabaci populations in Western USA onions harbor multiple mechanisms of resistance including enhanced activities of detoxification enzymes and target site insensitivity. Our results provide new information in understanding the dynamics of T. tabaci adaptation to multiple insecticides, which will help to design sustainable insecticide resistance management strategies for T. tabaci. Furthermore, this study provides the foundation for future research in identifying the biochemical and molecular markers associated with insecticide resistance in T. tabaci.

<p><strong>Diversity of <em>Gyroporus</em> (Gyroporaceae, Boletales): <em>rpb2</em> phylogeny and three new species</strong></p>

Three new species of Gyroporus, one from the southern hemisphere (Gyroporus madagascariensis sp. nov.) and two from the northern hemisphere (Gyroporus borealis sp. nov. and Gyroporus smithii sp. nov.), are described. G. madagascariensis is a brownish bolete currently known from Madagascar; it has a mottled pileus somewhat reminiscent of G. mcnabbii, another species known from the southern hemisphere. G. borealis is known from the northeastern United States and is also recorded from the northwestern United States under planted landscape trees. G. smithii corresponds to an orange-colored species that has often been encountered in the United States west and south of the Appalachian Mountains (east of the Great Plains) and is likely often mistaken for G. borealis, which can display orange coloration. Additionally, this study presents evidence that G. roseialbus Murrill and G. subalbellus Murrill, previously synonymized by Rolf Singer, are in fact distinct species.

Economically Optimal Wheat Yield, Protein and Nitrogen Use Component Responses to Varying N Supply and Genotype.

Improvements in market value of hard red spring wheat (HRS, Triticum aestivum L.) are linked to breeding efforts to increase grain protein concentration (GPC). Numerous studies have been conducted on the identification, isolation of a chromosome region (Gpc-B1) of Wild emmer wheat (Triticum turgidum spp. dicoccoides) and its introgression into commercial hard wheat to GPC. Yet there has been limited research published on the comparative responsiveness of these altered lines and their parents to varied N supply. There is increased awareness that wheat genetic improvements must be assessed over a range of environmental and agronomic management conditions to assess stability. We report herein on economically optimal yield, protein and nitrogen use efficiency (NUE) component responses of two Pacific Northwestern USA cultivars, Tara and Scarlet compared to backcrossed derived near isolines with or without the Gpc-B1 allele. A field experiment with 5 N rates as whole plots and 8 genotypes as subplots was conducted over two years under semi-arid, dryland conditions. One goal was to evaluate the efficacy of the Gpc-B1 allele under a range of low to high N supply. Across all genotypes, grain yield responses to N supply followed the classic Mitscherlich response model, whereas GPC followed inverse quadratic or linear responses. The Gpc-B1 introgression had no major impact on grain protein, but grain N and total above ground crop N yields demonstrated quadratic responses to total N supply. Generally, higher maximum grain yields and steeper rise to the maxima (Mitscherlich c values) were obtained in the first site-year. Tara required less N supply to achieve GPC goals than Scarlet in both site-years. Genotypes with Gpc-B1 produced comparable or slightly lower Mitscherlich A values than unmodified genotypes, but displayed similar Mitscherlich c values. Target GPC goals were not achieved at economic optimal yields based on set wheat pricing. Economic optimization of N inputs to achieve protein goals showed positive revenue from additional N inputs for most genotypes. While N uptake efficiency did not drop below 0.40, N fertilizer-induced increases in grain N harvest correlated well with unused post-harvest soil N that is potentially susceptible to environmental loss.

Long‐Term Trends of High Aerosol Pollution Events and Their Climatic Impacts in North America Using Multiple Satellite Retrievals and Modern‐Era Retrospective Analysis for Research and Applications version 2

AbstractMean magnitudes and temporal trends in aerosol optical depth (AOD) from satellite observations and an aerosol reanalysis exhibit a negative‐positive east‐northwest dipole across the contiguous United States with large magnitude negative trends over the eastern United States while small magnitude positive trends over the northwestern states. Based on analyses of Modern‐Era Retrospective Analysis for Research and Applications version 2, the AOD reduction over the eastern United States appears to be largely attributable to reductions in aerosol sulfate, while there have been marked increases in aerosol‐organic and elemental carbon over almost all of the contiguous United States and particularly the northwestern states. Long‐term trends of high aerosol pollution events (HAPEs; days with AOD over the long‐term local 90th daily AOD percentile) during 2000–2017 also indicate that over the eastern United States, both the frequency and spatial scale of summer HAPEs exhibit significant negative trends, while those of moderate aerosol events (days with AOD between the local 30th and 70th AOD percentiles) exhibit weak upward trends. Opposing trends, of smaller magnitude, are derived in the northwestern United States and southwestern Canada. Net and shortwave solar radiation show positive trends at the surface and top of atmosphere under clear‐sky conditions over the eastern United States consistent with the reduction in AOD. However, skin temperatures do not indicate significant trends during all days or HAPEs, indicating that the aerosol‐induced radiation trends are not sufficient to manifest trends in surface temperature. Precipitation during HAPEs appears to have increased during 2000–2017 over the eastern and central United States, indicating that the reduction in aerosol may already be enhancing the precipitation through aerosol‐cloud interactions.

Parents Matter: Examination of Family Presence in the Neonatal Intensive Care Unit.

The aim of this study is to examine presence trends for parents and family members during an infant's Neonatal Intensive Care Unit (NICU) hospitalization. We conducted a review of 386 infants hospitalized in a Level IV NICU in the Northwestern United States between June 2013 and April 2014 to quantitatively examine presence trends. Infants were visited by multiple family members. The father was the most common first family member at the bedside after admission. Parents were present over half of the days their infants were in the NICU (medians: mothers 75% and fathers 59%), but a relatively small percentage of the total hospitalization time (medians: 10% mothers and 5% fathers). Fathers', grandmothers', and grandfathers' presence with their infants in the NICU were negatively correlated with infants' total length of stay in the NICU. This finding was not replicated for mothers. Female family members were present in the NICU more than male family members. Parents are present a small percent of the time their infants are hospitalized in the NICU. NICU based methods to improve family presence may lead to improved patient and family centered care. · Mothers are present 10% of total NICU time.. · Fathers are present 5% of total NICU time.. · Fathers' presence was associated with a shorter stay.. · Grandparents' presence was associated with a shorter stay.. · Females were present significantly more than males..

Intra-individual associations between intentional self-regulation and prosocial behavior during adolescence: Evidence for bidirectionality

IntroductionCouched in Positive Youth Development (PYD) theory and relevant empirical work, this study investigated bidirectional associations between intentional self-regulation and prosocial behavior toward strangers from age 12 to age 18. MethodParticipants included 500 adolescents (52% female, 77% European American; age Time 1 = 12 years, Time 2 = 14 years, Time 3 = 16 years, Time 4 = 18 years) from the Northwestern United States. Adolescents self-reported on their intentional self-regulation and prosocial behavior toward strangers across four time points. A random-intercept cross-lagged panel model (RICLPM) was estimated in order to assess bidirectionality while avoiding conflating intra- and inter-individual variability. ResultsResults revealed intentional self-regulation and prosocial behavior toward strangers were bidirectionally related during early adolescence (i.e., from age 12 to 14). During mid-to-late adolescence (i.e. age 14 to 18), prosocial behavior toward strangers facilitated intentional selfregulation, whereas intentional self-regulation did not drive the development of prosocial behavior toward strangers. ConclusionsFindings indicate that early adolescence may be a particularly plastic developmental period in terms of PYD. Findings also suggest that investigations of relations between adolescents' personal assets and contribution factors merit further scholarly attention. Several directions for future research are presented.

American black bear population fragmentation detected with pedigrees in the transborder Canada–United States region

Population fragmentation is stressing wildlife species worldwide. In populations with minimal genetic structure across potential fractures, detecting fragmentation can be challenging. Here we apply a relatively unused approach, genetic pedigree analysis, to detect fragmentation in the American black bear (Ursus americanus) across 2 highway corridors that are bordered by large, contiguous populations. We compared our results with movements detected through Global Positioning System (GPS) telemetry of collared bears between 2005 and 2010. We used 20-locus microsatellite genotypes to identify 104 first-order relatives (parent–offspring or full siblings) within 383 black bears, sampled between 2002 and 2012. We compared numbers of pairs of immediate relatives found on either side of 2 highways—U.S. Highway 2 in northwestern Montana, USA, and BC Highway 3 in southeastern British Columbia, Canada—with an expected rate, the mean across 22 lines parallel to each highway at 1-km intervals. We found that over similar geographic scales, dispersal was lower across the transportation corridors than adjacent areas without a highway corridor. The observed number of migrants across Highway 2 was 3, well below the confidence interval of the expected number of 15.1 migrants/available bears (95% CI = 12.2–18.0). Highway 3 had 6 migrants, compared with the expected 13.1 bears (95% CI = 10.8–15.5). None of 16 black bears wearing GPS radiocollars for 1 year crossed Highway 2, yet 6 of 18 crossed Highway 3. These results suggest that even though 33% of radiocollared black bears crossed Highway 3, there appeared to be less dispersal across the transportation corridors than across other regions in the study area. Pedigree and telemetry results were more closely aligned in the Highway 2 system, with both methods suggesting more intense fragmentation than we found along Highway 3. Our results identified pedigree analysis as another tool for investigating population fragmentation, particularly in situations where genetic differentiation is too weak to determine migration rates using individual-based methods, such as population assignment.

Using Motivational Interviewing to Improve Parenting Skills and Prevent Problem Behavior During the Transition to Kindergarten

In this study, we examined the efficacy of a version of the Family Check-Up (FCU) adapted for kindergarten school entry with regard to parenting skills during the transition to school. We also examined whether improvements in parenting skills would mediate improvements in parent- and teacher-rated child behavior problems from kindergarten to second grade. The FCU is a motivational interviewing (MI) intervention designed to engage parents in treatment to improve parenting skills. Participants were parents of 365 children enrolled in one of five elementary schools in the Pacific Northwestern United States. Main and indirect effects were tested with structural equation path modeling using an intent-to-treat approach. The FCU was associated with improved change in parenting skills, and changes in parenting skills, in turn, predicted reductions in child behavior problems. Implications for embedding MI in family-centered interventions at kindergarten school entry are discussed. Trial registration: NCT02289092

Reshuffling the Columbia River Basalt chronology—Picture Gorge Basalt, the earliest- and longest-erupting formation

Abstract The Columbia River Basalt Group (CRBG) is the world’s youngest continental flood basalt province, presumably sourced from the deep-seated plume that currently resides underneath Yellowstone National Park in the northwestern United States. The earliest-erupted basalts from this province aid in understanding and modeling plume impingement and the subsequent evolution of basaltic volcanism. We explore the Picture Gorge Basalt (PGB) formation of the CRBG, and discuss the location and geochemical significance in a temporal context of early CRBG magmatism. We report new ARGUS-VI multicollector 40Ar/39Ar incremental heating ages from known PGB localities and additional outcrops that we can geochemically classify as PGB. These 40Ar/39Ar ages range between 17.23 ± 0.04 Ma and 16.06 ± 0.14 Ma, indicating that PGB erupted earlier and for longer than other CRBG main-phase units. These ages illustrate that volcanism initiated over a broad area in the center of the province, and the geochemistry of these early lavas reflects a mantle source that is distinct both spatially and temporally. Combining ages with the strongest arc-like (but depleted) geochemical signal of PGB among CRBG units indicates that the shallowest metasomatized backarc-like mantle was tapped first and concurrently, with later units (Steens and Imnaha Basalts) showing increased influence of a plume-like source.

If the trees burn, is the forest lost? Past dynamics in temperate forests help inform management strategies.

Forest dynamics are driven by top-down changes in climate and bottom-up positive (destabilizing) and negative (stabilizing) biophysical feedbacks involving disturbance and biotic interactions. When positive feedbacks prevail, the resulting self-propagating changes can potentially shift the system into a new state, even in the absence of climate change. Conversely, negative feedbacks help maintain a dynamic equilibrium that allows communities to recover their pre-disturbance characteristics. We examine palaeoenvironmental records from temperate forests to assess the nature of long-term stability and regime shifts under a broader range of environmental forcings than can be observed at present. Forest histories from northwestern USA, Patagonia, Tasmania and New Zealand show long-term trajectories that were governed by (i) the biophysical template, (ii) characteristics of climate and disturbance, (iii) historical legacies that condition the ecological capacity to respond to subsequent disturbances, and (iv) thresholds that act as irreversible barriers. Attention only to current forest conditions overlooks the significance of history in creating path dependency, the importance of individual extreme events, and the inherent feedbacks that force an ecosystem into reorganization. A long-time perspective on ecological resilience helps guide conservation strategies that focus on environmental preservation as well as identify vulnerable species and ecosystems to future climate change. This article is part of the theme issue 'Climate change and ecosystems: threats, opportunities and solutions'.

Converting Conventional Agriculture to Poplar Bioenergy Crops: Soil Chemistry

ABSTRACTWoody bioenergy is a viable source of alternative energy; however, questions remain on how purpose-grown bioenergy feedstock production management impact surface soil chemistry. In order to understand the soil processes under poplar (Populus spp.) trees and adjacent agricultural sites, surface (0–15 cm) soil samples were collected from four northwestern United States locations over a four-year period. Initial and final surface soil samples were analyzed for various soil chemical parameters, including organic matter, pH, cation exchange capacity and nutrient concentrations. Fields selected to compare poplar and agricultural management initially differed in some key soil chemical parameters. Many soil chemical parameters changed over time and the magnitude of change often depended on location; however, initial differences between management types within any one location did not change over time for most soil chemical variables. Consistent in-location differences between management types over time show poplar did not alter soil chemical parameters relative to agricultural management during the study period. Together all observations indicate that little of the overall soil chemistry was impacted by the introduction of poplar in the traditionally agricultural fields.

Genome structure and apomixis in Phoenicaulis (Brassicaceae; Boechereae)

AbstractApomixis in crucifer (Brassicaceae) species is rare, reported in just four genera (Boechera, Draba, Erysimum, and Parrya), and one intergeneric hybrid (Raphanobrassica). It is well studied only in Boechera, where it is widespread among 100+ recognized species. However, its occurrence in related genera of the tribe Boechereae has not been documented previously. Here we analyzed genome evolution, mode of reproduction, and fertility of the monospecific Boechereae genus Phoenicaulis (P. cheiranthoides), endemic to the northwestern United States. We discovered that the species encompasses diploid (2n = 2x = 14), triploid (2n = 3x = 21), and tetraploid (2n = 4x = 28) populations. Comparative chromosome painting analyses revealed that the three karyotypes are essentially structurally identical, differing only in the presence of a largely heterochromatic chromosome (Het) in the triploid and tetraploid cytotypes. The genome structure of Phoenicaulis appeared identical to that of Boechera species previously analyzed, suggesting genomic stasis despite the morphological and molecular divergence of the two genera. This genome colinearity extended to the presence and structure of the Het chromosomes, which are closely associated with apomictic reproduction in Boechera. Interestingly, all three cytotypes of Phoenicaulis proved to be apomictic, regardless of the presence or absence of a Het chromosome, and sexual populations have yet to be identified.

Asian technical experts: skilled corporate migration in the global commodity chain

AbstractIn this article I discuss the relocation of skilled employees from the peripheral operating regions of transnational corporations to their operating centres. I examine employees who migrated from regional offices in East and Southeast Asian countries to the headquarters of two athletic footwear companies based in the northwestern United States. Drawing on 12 in‐depth interviews and six months of ethnographic fieldwork, I contextualize corporate migration within the global athletic footwear commodity chain and argue that the layers of asymmetrical power within the industry construct a specific identity profile of the ‘Asian technical expert’ based on employees' embodiment of technical capital, geographical origin, and corporate rank. This identity profile gives regional office employees opportunities for mobility, while creating both empowerment and constraints that structure post‐migration experiences. In this study, by examining migrants from countries that are fairly low down in the global commodity chain hierarchy, I hope to expand both the theoretical framework available to corporate migration scholars and the range of migration considered.

How to measure the economic health cost of wildfires – A systematic review of the literature for northern America

There has been an increasing interest in the economic health cost from smoke exposure from wildfires in the past 20 years, particularly in the north-western USA that is reflected in an emergent literature. In this review, we provide an overview and discussion of studies since 2006 on the health impacts of wildfire smoke and of approaches for the estimation of the associated economic cost. We focus on the choice of key variables such as cost estimators for determining the economic impact of mortality and morbidity effects. In addition, we provide an in-depth discussion and guidance on the functioning, advantages and challenges of BenMAP-CE, freely available software of the US Environmental Protection Agency (EPA) that has been used in a growing number of studies to assess cost from wildfire smoke. We highlight what generates differences in outcomes between relevant studies and make suggestions for increasing the comparability between studies. All studies, however, demonstrate highly significant health cost from smoke exposure, in the millions or billions of US dollars, often driven by increases in mortality. The results indicate the need to take health cost into account for a comprehensive analysis of wildfire impacts.

Assessing water quality changes in agricultural drainages: Examples from oxbow lake tributaries in northwestern Mississippi, United States, and simulation-based power analyses

Hydrology (streamflow and stage) and water quality (suspended sediment, total nitrogen [N], ammonia [NH₃], total Kjeldahl N, nitrate plus nitrite [NO₃ + NO₂], and total phosphorus [TP]) were monitored in two small agricultural drainages in northwestern Mississippi to document changes in water quality that coincided with the implementation of best management practices (BMPs) in upstream drainages. Using an event-based data set and bootstrapping techniques, we tested for difference and equivalence in median event concentration and differences in concentration-streamflow (C-Q) relationships between an early and late period at each site, where most of the major BMP implementation occurred during the early period. Results for Bee Lake Tributary were inconclusive. Using 95% confidence intervals, none of the constituents were statistically different or equivalent for median event concentrations between the periods, indicating a lack of evidence to determine whether water quality had changed or stayed the same, and only TP had a significantly higher C-Q intercept during the late period. At Lake Washington Tributary, more than half the constituents had a significantly different median, slope, or intercept between periods, indicating a 35% or more decrease in event concentration following a period of intense BMP implementation. These mixed results could be due to a variety of differences between the sites including the type and timing of BMP implementation, production practices, and crop types. We also used the monitoring data to generate synthetic data and performed a simulation-based power analysis to explore the ability to detect change under 25 scenarios of sampled event counts and hypothetical percentage changes. The simulation-based power analysis indicated that natural variability in event concentration and flow hindered our ability to detect change. The results from this study can be used to guide future decisions pertaining to monitoring efforts in small agricultural drainage basins in the Mississippi Alluvial Plain.