National Resources Inventory Data Research Articles

Evaluation of Conservation Effects Assessment Project Grazing Lands conservation practices on the Cienega Creek watershed in southeast Arizona with AGWA/RHEM modeling tools

The Automated Geospatial Watershed Assessment Tool (AGWA) and the Rangeland Hydrology Erosion Model (RHEM) were used to evaluate conservation practices on the Cienega Creek watershed (CCW) that were implemented under the Conservation Effects Assessment Project (CEAP) on Grazing Lands. CEAP on Grazing Lands is a multi-agency effort to quantify the environmental effects of conservation practices and programs, and develop the science base for managing rangelands for environmental quality using conservation practices (Spaeth et al. 2013). The evaluation was performed on the CCW and the Empire Ranch, located in southeastern Arizona, where numerous conservation practices have been implemented to achieve their management goals of maintaining desired plant communities and watershed processes. To assess the effects of the conservation practices on long-term soil and water loss, RHEM was applied to the entire CCW using National Resources Inventory (NRI) data. Four analysis periods were selected based on climatic contrasts, conservation spending, and availability of NRI sample points. The CCW results showed that the simulations using RHEM parameters derived from NRI data could be used to demonstrate the impact of climate on vegetation condition and sediment yield. A subsection, dubbed “select treatment areas,” of the CCW, which received extensive treatments with brush removal, prescribed burns, and stock ponds, was assessed using remotely sensed data. The select treatment areas were modeled over three different periods, representing preconservation spending, postconservation spending, and later postconservation spending. Remote sensing was capable of detecting and estimating the changes in vegetation cover from brush removal and prescribed burns. Simulations of sediment yield using pre- and posttreatment data indicated a modest reduction in sediment yield. Simulations in the select treatment areas indicated mechanical brush treatments were typically more effective than prescribed burns for improving watershed condition as estimated by reductions in sediment yield, but were more costly to implement. Stock ponds had a larger impact on sediment yield than the land treatments. The assessment demonstrated the utility of remotely sensed estimates of plant growth form and cover for model inputs to estimate changes in runoff and sediment yield with changing cover conditions over large areas.

Understanding the effects of grazing and prescribed fire on hydrology of Kentucky bluegrass–dominated rangelands in the northern Great Plains

According to National Resources Inventory data, Kentucky bluegrass (Poa pratensis L.) is now present in over 85% of the areas sampled. This invasive, perennial, cool season grass can serve to stabilize soils and increase site stability; however, it also alters nutrient flows, soil structure, and plant community composition, ultimately degrading biotic integrity. In addition, Kentucky bluegrass alters the hydrologic function of an area by changing root structure and the way in which water flow is captured and released back into the ecosystem. To clarify the effect of Kentucky bluegrass on hydrological characteristics of invaded sites, rainfall simulation experiments and hydrophobicity measurements with water drop infiltration time and molarity of ethanol droplet tests were conducted at three locations all within the same ecological site in the northern Great Plains. Rainfall simulation experiments were performed on 24 large plots (6 × 2 m) at 63.5 mm h−1 and 127 mm h−1 intensities and on 16 small plots (0.7 × 0.7 m) at 63.5 mm h−1 and 103 mm h−1. Rainfall was maintained on the large plots until 10 minutes of steady-state runoff was measured or for a maximum of 30 minutes in the absence of runoff, while on the small plots, rainfall duration was set at 25 minutes. The soil layer was divided into four strata (litter, thatch, root mat, and mineral soil), which were physically separated for their hydrophobic behavior in laboratory and field water drop penetration tests and molarity analyses. Our results indicate that on dry soil strata, water drop penetration time increased by 20 seconds on litter and 3 seconds on thatch for every percentage point increase in Kentucky bluegrass in the vegetation, confirming the close association between this grass species and the development of soil hydrophobicity. Rainfall simulation on dry soils (less than 20% volumetric water content) also revealed that the time needed to initiate runoff was shortened by 5 minutes, and the runoff ratio increased by 0.004 for every percentage point increase of Kentucky bluegrass in the vegetation cover. Hydrophobicity dramatically declined in the thatch layer by a factor of 4 and was completely absent from the litter layer after wetting. In contrast to the rainfall simulations on dry soils, wet runs (volumetric water content ≥20%) showed a beneficial effect of Kentucky bluegrass on hydrologic response with delayed runoff by 5 minutes and reduced runoff ratios by 0.003 for 1% increase in Kentucky bluegrass in the vegetation cover. Prescribed fire increased litter hydrophobicity, but this did not adversely affect hydrologic response. This study highlights the need for further research contrasting detrimental effects of Kentucky bluegrass on hydrologic response in dry soil conditions with the beneficial effect of this grass on infiltration under wet conditions to better predict the overall ecohydrological outcome of an invasion by this grass species.

Application of a rangeland soil erosion model using National Resources Inventory data in southeastern Arizona

Rangelands comprise a large portion of the western United States. They are impor- tant for providing ecosystem services such as sources of clean water and air, wildlife habitat, ecosystem biodiversity, recreation, and aesthetics. The National Resources Inventory (NRI) is a primary data source for ongoing assessment of nonfederal land in the United States, including rangelands, and the data collected during an NRI assessment is typical of rangeland monitoring conducted by managers. This study outlines a methodology for using that type of monitoring data to run a rangeland hydrology and erosion model in order to estimate the relative soil erosion rates across ecosystems located in the American Southwest. The model was run on 134 NRI rangeland field locations with data collected between 2003 and 2006 in Major Land Resource Area 41, the Southeastern Arizona Basin and Range, which is a diverse ecological area of 40,765 km 2 (15, 739 mi 2 ) in the transition zone between the Sonoran and Chihuahuan deserts. Results of the study showed that the data collected was adequate to run the model and effectively assess the influence of foliar cover, ground cover, plant life forms, soils, and topography on current soil erosion rates. Results suggested that the model could be further improved with additional measured experimental data on infiltration, runoff, and soil erosion within key ecological sites in order to better quantify model parameters to reflect ecosystem changes and risk of crossing interdependent biotic and abiotic thresholds.

Soil erosion hazard maps for corn stover management using National Resources Inventory data and the Water Erosion Prediction Project

A topographic map of auditory space is a feature found in the superior colliculus (SC) of many species, including CBA/CaJ mice. In this genetic background, high-frequency monaural spectral cues and interaural level differences are used to compute spatial receptive fields (RFs) that form a topographic map along the azimuth. Unfortunately, C57BL/6 mice, a strain widely used for transgenic manipulation, display age-related hearing loss (AHL) due to an inbred mutation in the Cadherin 23 gene (<i>Cdh23)</i> that affects hair cell mechanotransduction. To overcome this problem, researchers have used young C57BL/6 mice in their studies, as they have been shown to have normal hearing thresholds. However, important details of the auditory response characteristics of the SC such as spectral responses and spatial localization, have not been characterized in young C57BL/6 mice. Here we show that 2-4-month C57BL/6 mice lack neurons with frontal auditory RFs and therefore lack a topographic representation of auditory space in the SC. Analysis of the spectrotemporal receptive fields (STRFs) of the SC auditory neurons shows that C57BL/6 mouse SC neurons lack the ability to detect the high-frequency (&gt;40kHz) spectral cues that are needed to compute frontal RFs. We also show that crossing C57BL/6 mice with CBA/CaJ mice or introducing one copy of the wild-type <i>Cdh23</i> to C57BL/6 mice rescues the high-frequency hearing deficit and improves the topographic map of auditory space. Taken together, these results demonstrate the importance of high-frequency hearing in computing a topographic map of auditory space. <b>Significance Statement</b> Despite the strain’s age-dependent hearing loss, C57BL/6 mice are widely used in auditory studies because of the development of transgenic reporter and Cre lines in this genetic background. Here we examined the topographic map of auditory space and spectrotemporal properties of neurons in the SC of C57BL/6 mice. We found an early-onset high-frequency hearing deficit that results in the loss of SC neurons with frontal RFs and, consequently, an absence of a topographic map of auditory space. These findings stress the importance of high-frequency hearing to compute spatially restricted receptive fields and serve as a caution to researchers that doing auditory-related research using the C57BL/6 genetic background may not be representative of true wild-type mice.

Past and projected rural land conversion in the US at state, regional, and national levels

The developed land area of the US increased by 14.2 million hectares between 1982 and 2003. Along with a projected US population increase to more than 360 million individuals by 2030 is an expected continuation of expanding rural land development. Related to population growth, rural land development and the associated loss of rural open space are expected to have a number of social, economic, and ecological implications. To gain greater insight into land development patterns, we used US Census Bureau and National Resources Inventory data to quantify per-housing-unit rates of land development during recent decades and to model future land development to 2030 for states and regions in the US. Based on these data, 0.50 ha of additional land were developed for each additional housing unit in the US. The numbers of hectares of newly developed land per additional housing unit were greatest in the South Central and Great Plains regions and least in the Pacific Coast and Rocky Mountain regions of the country. Combining population projections and trends in people per housing unit with development indices, we projected that developed area in the US will increase by 22 million hectares between 2003 and 2030, with the greatest absolute increases projected to occur in the Southeast and South Central regions of the US. We used sensitivity analysis to examine the impacts of changes in population migration patterns and per housing unit development patterns on increases in projected developed area.

Effects of the Conservation Reserve Program on northern bobwhite and grassland birds

The Conservation Reserve Program (CRP) has converted just over 36 million acres of cropland into potential wildlife habitat, primarily grassland. Thus, the CRP should benefit grassland songbirds, a group of species that is declining across the United States and is of conservation concern. Additionally, the CRP is an important part of multi-agency, regional efforts to restore northern bobwhite populations. However, comprehensive assessments of the wildlife benefits of CRP at regional scales are lacking. We used Breeding Bird Survey and National Resources Inventory data to assess the potential for the CRP to benefit northern bobwhite and other grassland birds with overlapping ranges and similar habitat associations. We built regression models for 15 species in seven different ecological regions. Forty-nine of 108 total models contained significant CRP effects (P < 0.05), and 48 of the 49 contained positive effects. Responses to CRP varied across ecological regions. Only eastern meadowlark was positively-related to CRP in all the ecological regions, and western meadowlark was the only species never related to CRP. CRP was a strong predictor of bird abundance compared to other land cover types. The potential for CRP habitat as a regional conservation tool to benefit declining grassland bird populations should continue to be assessed at a variety of spatial scales. We caution that bird-CRP relations varied from region to region and among species. Because the NRI provides relatively coarse resolution information on CRP, more detailed information about CRP habitats (spatial arrangement, age of the habitat (time since planting), specific conservation practices used) should be included in future assessments to fully understand where and to what extent CRP can benefit grassland birds.

Land Use Change, Resource Competition and Conflict in the Southern United States: Discussion

These three papers together characterize trends in land use, resource issues, and research responses that are being observed in all regions of the country. However, southern states are the locus of the most recent and rapid changes in land use. The latest National Resources Inventory data shows that the increase in acreage of land in developed uses from 1992 through 1997 was most pronounced in the southern states. Figure 1 compares, for all states but Alaska, the average annual rate of land development (this is land moved into the urban and built-up category and the rural transportation land category) between 1992 and 1997. Eight of the top 13 states are in the southern region, and Louisiana, the southern state with the lowest rate of land development, is ranked at 29th out of 49.

THE EFFICIENCY OF SEQUESTERING CARBON IN AGRICULTURAL SOILS

Agricultural tillage practices are important human‐induced activities that can alter carbon emissions from agricultural soils and have the potential to contribute significantly to reductions in greenhouse gas emission (Lal et al., The Potential of U.S. Cropland, 1998). This research investigates the expected costs of sequestering carbon in agricultural soils under different subsidy and market‐based policies. Using detailed National Resources Inventory data, we estimate the probability that farmers adopt conservation tillage practices based on a variety of exogenous characteristics and profit from conventional practices. These estimates are used with physical models of carbon sequestration to estimate the subsidy costs of achieving increased carbon sequestration with alternative subsidy schemes.

The efficiency of sequestering carbon in agricultural soils

Agricultural tillage practices are important human-induced activities that can alter carbon emissions from agricultural soils and have the potential to contribute significantly to reductions in greenhouse gas emission (Lal et al., The Potential of U.S. Cropland, 1998). This research investigates the expected costs of sequestering carbon in agricultural soils under different subsidy and market-based policies. Using detailed National Resources Inventory data, we estimate the probability that farmers adopt conservation tillage practices based on a variety of exogenous characteristics and profit from conventional practices. These estimates are used with physical models of carbon sequestration to estimate the subsidy costs of achieving increased carbon sequestration with alternative subsidy schemes.

Drainage Investment and Wetlands Loss: an Analysis of the National Resources Inventory Data

The United States Soil Conservation Service (SCS) conducts a survey for the purpose of establishing an agricultural land use database. This survey is called the National Resources Inventory (NRI) database. The complex NRI land classification system, in conjunction with the quantitative information gathered by the survey, has numerous applications. The current paper uses the wetland area data gathered by the NRI in 1982 and 1987 to examine empirically the factors that generate wetland loss in the United States. The cross-section regression models listed here use the quantity of wetlands, the stock of drainage capital, the realty value of farmland and drainage costs to explain most of the cross-state variation in wetland loss rates. Wetlands preservation efforts by federal agencies assume that pecuniary economic factors play a decisive role in wetland drainage. The empirical models tested in the present paper validate this assumption.

Preparation of the National Resources Inventory Data Base for Ground-Truthing Satellite-Collected Land-Use and Land-Cover Data

A low-cost procedure utilizing an acoustical digitizer and a minicomputer to prepare National Resources Inventory (NRI) data for secondary use as material for ground-truthing satellite-collected data is described. A labor-intensive aspect of processing satellite-collected data is the making of ground surveys to determine what land cover is portrayed by a given picture “color” from space. The procedure described covers entering the locational aspects of NRI sample points for later comparisons of satellite data and collected NRI data.