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Research about Midwest region

Source-linked reports with geographic coverage including Midwest region.

7 recordsLinked to original sources
USGS2025

U.S. national park units as breeding bird habitat: A comparison of species prevalence and land cover across the midwestern and central United States

The value of national parks as bird habitat depends not only on local conditions within the parks, but also on the landscape habitat matrices in which they are located. However, the influences of local and landscape habitat matrices on birds vary by species and have not been quantified. Similarly, the trends of land cover types through time have not been systematically quantified for Midwest Region national parks and the landscapes around them, despite evidence of ongoing habitat loss exacerbated by climate change and human population growth. Managers and policy makers can use this information to understand and sustain the contribution of parks to our Nation’s avifauna. We developed models using North American Breeding Bird Survey (BBS) data collected on routes from across the central United States. The models were used to predict occupancy of bird species of concern in 32 national park units across nine Bird Conservation Regions in the Midwest based on land cover in and around those parks. We then compared these predictions with data collected through National Park Service (NPS) bird surveys at each park to determine if bird species of concern were more or less prevalent than expected. In each park, the mean difference between observed species detections and mean predicted detections indicates that most species are less frequently detected in the parks than predicted. However, when the range of uncertainty of predictions is considered, only 21% of park-bird combinations showed strong evidence (95%) of differing from expectation. Of these, species were less common than expected in the park in all but two cases. These results indicate that some bird species of concern occupy sites in Midwest Region national park units at a rate roughly comparable to sites with similar land cover in the Bird Conservation Region (BCR) in which they occur. However, for one in five species-park combinations, parks appear to be less occupied than comparable sites elsewhere.

Midwest region↗
USGS2005

Summary of significant results from studies of triazine herbicides and their degradation products in surface water, ground water, and precipitation in the midwestern United States during the 1990s

Nonpoint-source contamination of water resources from triazine herbicides has been a major water-quality issue during the 1990s in the United States. To address this issue, studies of surface water, ground water, and precipitation have been carried out by the U.S. Geological Survey in the Midwestern United States. Reconnaissance studies of 147 streams were conducted to determine the geographic and seasonal distribution of atrazine, cyanazine, propazine, and simazine. These studies showed that high concentrations of herbicides were flushed from cropland and transported through the stream system as pulses in response to spring and summer rainfall. The studies also revealed the persistence of herbicides and their degradation products in streams. An investigation of 76 reservoirs showed that the occurrence and temporal distribution of herbicides and their degradation products in reservoir outflow could be related to reservoir and drainage-basin characteristics, water and land use, herbicide use, and climate. Significant findings showed that concentrations of atrazine and its degradation products remained elevated all summer and into the fall and that recently applied atrazine mixed with atrazine applied the previous year as water moved through a reservoir. Reconnaissance studies of 303 ground-water wells were completed to determine hydrogeological and seasonal occurrence, concentration, and distribution of herbicides and their degradation products. Samples collected from across the Midwestern United States consistently revealed that triazine herbicide degradation products commonly were found more frequently than their parent herbicide and that ground-water age could be an important factor in explaining variations in herbicide contamination. A final study investigated precipitation in the Midwestern United States, northeast to the Atlantic Ocean, and northward to the Canadian border. It found that the highest herbicide concentrations in precipitation occurred following herbicide application to cropland. Atrazine was detected most often, followed by deethylatrazine, cyanazine, and deisoproplyatrazine. Mass deposition of herbicides by precipitation was greatest in areas where herbicide use was intense and decreased with distance from the Midwest. Findings of the 1990s studies include an improved understanding of the occurrence, persistence, chemistry, and transport of triazine herbicides and their degradation products in the hydrologic environment. A significant increase in knowledge of triazine herbicides and development and improvement of analytical methods were accomplished in the past decade. The results produced are not only significant for the present (2005) but provide an important data set for future use.

Midwest region↗
USGS2004

Aquifer vulnerability to pesticide pollution: Combining soil, land-use and aquifer properties with molecular descriptors

This study uses an extensive survey of herbicides in groundwater across the midwest United States to predict occurrences of a range of compounds across the region from a combination of their molecular properties and the properties of the catchment of a borehole. The study covers 100 boreholes and eight pesticides. For each of the boreholes its catchment the soil, land-use and aquifer properties were characterized. Discriminating boreholes where pollution occurred from those where no pollution occurred gave a model that was 74% correct with organic carbon content, percentage sand content and depth to the water table being significant properties of the borehole catchment. Molecular topological descriptors as well as K oc , solubility and half-life were used to characterize each compound included in the study. Inclusion of molecular properties makes it possible to discriminate between occurrence and non-occurrence of each compound in each well. The best-fit model combines: organic carbon content, percentage sand content and depth to the water table with molecular descriptors representing molecular size, molecular branching and functional group composition of the herbicides.

Midwest region↗
USGS2003

Herbicides and herbicide degradation products in upper midwest agricultural streams during august base-flow conditions

Herbicide concentrations in streams of the U.S. Midwest have been shown to decrease through the growing season due to a variety of chemical and physical factors. The occurrence of herbicide degradation products at the end of the growing season is not well known. This study was conducted to document the occurrence of commonly used herbicides and their degradation products in Illinois, Iowa, and Minnesota streams during base-flow conditions in August 1997. Atrazine, the most frequently detected herbicide (94%), was present at relatively low concentrations (median 0.17 μg L −1 ). Metolachlor was detected in 59% and cyanazine in 37% of the samples. Seven of nine compounds detected in more than 50% of the samples were degradation products. The total concentration of the degradation products (median of 4.4 μg L −1 ) was significantly greater than the total concentration of parent compounds (median of 0.26 μg L −1 ). Atrazine compounds were present less frequently and in significantly smaller concentrations in streams draining watersheds with soils developed on less permeable tills than in watersheds with soils developed on more permeable loess. The detection and concentration of triazine compounds was negatively correlated with antecedent rainfall (April–July). In contrast, acetanalide compounds were positively correlated with antecedant rainfall in late spring and early summer that may transport the acetanalide degradates into ground water and subsequently into nearby streams. The distribution of atrazine degradation products suggests regional differences in atrazine degradation processes.

Midwest region↗
USGS2003

Work plan for determining the occurrence of glyphosate, its transformation product AMPA, other herbicide compounds, and antibiotics in midwestern United States streams, 2002

Changes in herbicide use in the Midwestern United States have been substantial over the last 5 years. Most significant is a tripling in the use of glyphosate (N-[phosphonomethyl]glycin). Over this same time period (1997­2001), atrazine use increased by 20 percent and acetochlor use increased by 10 percent, while cyanazine use decreased by 99 percent, alachlor use decreased by 70 percent, and metolachlor use decreased by 55 percent. Previous studies have documented that herbicide flushes occur in midwestern streams during runoff events for several weeks to several months following application, and that herbicide concentrations in midwestern streams during flushing events are related to rates of herbicide use. The objective of this study is to determine the distribution of glyphosate and its primary transformation product aminomethylphosphonic acid (AMPA) in midwestern streams during post-application and harvest-season runoff events. Water samples will be collected in 2002 during two post-herbicide-application runoff events and one harvest-season runoff event from 53 sites on streams in the Midwestern United States. All samples will be analyzed at the U.S. Geological Survey Organic Geochemistry Research Laboratory in Lawrence, Kansas, for glyphosate and 20 other herbicides. Samples will also be analyzed for a glyphosate transformation product (AMPA) and 26 other herbicide transformation products, using GC/MS or HPLC/MS. Selected samples will be analyzed for 36 antibiotics or antibiotic transformational products. Results from this study will represent the first broad-scale investigation of glyphosate and AMPA in U.S. water resources.

Midwest region↗
USGS2002

Groundwater vulnerability: Interactions of chemical and site properties

This study brings together extensive, multi-annual groundwater monitoring datasets from the UK and Midwestern US to test the relative importance of site (e.g. land use, soil and aquifer type) and chemical factors (e.g. solubility in water) and between and within year variations in controlling groundwater contamination by pesticides. ANOVA (general linear modelling) was used to test the significance and proportion of variation explained by each factor and their interactions. Results from both the UK and US datasets show that: (i) Chemical and site factors both have a statistically significant influence on groundwater pollution; (ii) Site factors on their own explain a greater proportion of data variance than chemical factors on their own; (iii) Interaction between site and chemical factors represents the most important control on the occurrence of pesticides in groundwater; (iv) Variation within the year was slight but still significant while there was no significant difference between data from consecutive years. The combination of factors analysed in this study were sufficient to explain the majority of the variation in the data save for that ascribable to the analytical detection limit. The results provide statistical evidence that it is viable to develop both molecular methods and groundwater vulnerability as tools to understanding pollution, but that a greater emphasis should be placed on their interaction to fully understand pesticide contamination.

Midwest region↗