Prairie Dogs and Livestock in Rangeland Systems: Balancing Biodiversity and Production in the Northern Mixed-Grass Prairie

A major constraint of beef production within the Standing Rock Reservation has been identified as a reduction in rangeland quality due in large part to wide-scale colonization by black-tailed prairie dogs (Cynomys ludovicianus). The desire exists within the community to design a holistic framework which incorporates livestock management with the goal of increasing production and rangeland health while still maintaining increased diversity associated with prairie dogs. Prairie dogs reduce the carrying capacity of cattle on rangelands by up to 50% on occupied hectares through direct consumption of vegetation and waste due to clipping to improve detection of predators. Livestock stocking rates that do not account for the level of prairie dog occupation can result in a reduction in animal performance and a further decrease in rangeland productivity due to overgrazing. Research is needed to understand season-long use of grazing cattle on and off prairie dog towns to better inform land manager decisions aimed at reducing over-utilization of grasslands and allowing higher production of livestock. This dissertation study was part of a larger study that was conducted in northcentral South Dakota from 2012 to 2016. This dissertation sub-study was designed to evaluate the impact of prairie dogs and cattle on plant community production and composition, and to determine impacts of colonization on livestock grazing behavior, diet quality, and forage intake. Three pastures with varying levels of prairie dog occupation (0%, 20%, and 40%) were studied. Pasture stocking rates were adjusted to account for the level of forage removed by prairie dogs (50%) on active colonies. Two study treatments were evaluated: Ecological Site (n=3) and grazing treatment (n=4). Ecological sites (ES) were Shallow Loam, Loamy, and Thin Claypan. Grazing treatments included two in off-town locations (non-graze (NG) and cattle only graze (CG)) and two in ontown locations (cattle and prairie dog graze (CPD), and prairie dog only graze (PD)). These treatments and their interactions were evaluated to determine their effects on vegetation (e.g. standing crop, diversity, species richness, etc.) and livestock (e.g. animal weight gains, diet quality and quantity, etc.) parameters. Goals of the dissertation herein are to understand 1) the interactions of prairie dogs and livestock on plant communities and 2) the impact of prairie dog occupation on livestock production. Objectives of this dissertation are: 1) Evaluate plant community response to grazing on and off prairie dog towns to determine how livestock and prairie dogs alter plant community production and composition; 2) Develop strategies that enable identification of plant communities of interest on and off prairie dog towns using remote sensing techniques ; 3) Develop methods to utilize programming tools for efficient processing of GPS collar data ; 4) Evaluate relationships between plant communities and cattle grazing locations to identify patterns and trends in livestock grazing behavior throughout the growing season; 5) Evaluate diet nutrient composition and intake by cattle on plant communities on- and off-town over the grazing season; 6) Develop a framework of cattle nutrient consumption in pastures with varying levels of prairie dog occupation; and 7) Synthesize existing research and results from this dissertation to explore potential synergism between prairie dogs and cattle on the landscape from a systems approach. Vegetation analyses show a significant difference in standing crop biomass between grazing treatments, with sites grazed only by cattle having 36% more biomass than those grazed only by prairie dogs. Plant community data suggest that prairie dogs have a greater impact on production and species composition compared to cattle; percent composition of C3 grasses was greatest off-town, whereas percent composition of C4 grasses was greatest on-town. An invasive C3 species of concern in the Northern Great Plains, Kentucky bluegrass, was almost non-existent on-town, but increased substantially off-town over the 5 years of the study for all ES; the most dramatic increase occurred on the Thin Claypan ES. Species diversity was not different between grazing treatments, however species richness was generally greatest on-town. Additionally, for the entire duration of the study (2012-2016), 46 species were only observed on-town and 17 only observed off-town out of a total 113 species observed throughout the 5 years of the study. The remote sensing analyses show that Random Forest (RF) models were highly effective at predicting different vegetation types associated with on and off prairie dog town locations (misclassification rates \u3c 5% for each plant community). However, comparisons between the predicted plant community map using separate years indicate 6.7% of pixels on-town and 24.3% of pixels off-town changed class membership depending on the year. The results show that while RF models may predict with a high degree of accuracy, transition zones between plant communities and inter-annual differences in rainfall may cause instability in fitted models. An essential component of evaluating livestock behavior for this study was accomplished using GPG collars that record both location and activity. Traditional methods of hand-processing of GPS data require a large number of steps which are both time consuming and prone to errors. As part of this dissertation, methods were created to streamline the processing of livestock GPS collar data, resulting in a technical note publication. Due to the open source nature of Program R, custom functions can be created to merge GPS collar data, GIS data layers, and behavior algorithms to improve data processing efficiency. Plant communities of interest for the livestock behavior and intake components of this study were identified as grass-dominated on-town sites (PDG), forb-dominated ontown sites (PDF), and grass dominated off-town sites (NPD). Livestock behavior analyses from this study show cattle slightly prefer grazing on prairie dog towns, with shifts occurring to off-town locations over the duration of the grazing season. Crude protein (CP) content from diet samples for PDF sites were significantly greater than for PDG and NPD sites. Little difference in many of the diet metrics existed, however, between grass dominated sites (PDG and NPD). Despite higher CP content on forb dominated sites on-town (PDF), intake levels were depressed on these communities due to high bare ground and low vegetation production. Individual livestock performance (average daily gains) averaged over the entire length of the study, were 0.74 kg. /day for the 0% occupied pasture, 0.86 kg. /day for the 20% occupied pasture, and 0.85 kg. /day for the 40% occupied pasture. Reduced stocking rate in prairie dog pastures may have contributed to greater individual animal performance. Higher livestock performance for the prairie dog pastures is potentially due to access to a more diverse diet. Reduced stocking rates in prairie dog pastures, however, resulted in a reduction in overall livestock production in terms of kg / ha. At low levels of colonization in pastures, livestock may potentially benefit from increased diet selection, however, reduction in plant biomass on town may negate any potential gains at higher levels of colonization. The results from this study were combined to take a systems approach to understanding the impacts and interactions of prairie dogs and livestock on plant communities, and the impacts of prairie dog occupation on livestock production in northern mixed-grass prairie ecosystems. Our results indicate that having both on-town and off-town plant communities within a pasture can increase biodiversity and heterogeneity at broader landscape scales. Differences in plant community composition may increase diet diversity for grazing livestock, potentially benefiting individual animal gains, provided forage quantity is not limited. At low levels of colonization, livestock production may only be minimally impacted while still realizing benefits to biodiversity

Three Pathogens in Sympatric Populations of Pumas, Bobcats, and Domestic Cats: Implications for Infectious Disease Transmission

Anthropogenic landscape change can lead to increased opportunities for pathogen transmission between domestic and non-domestic animals. Pumas, bobcats, and domestic cats are sympatric in many areas of North America and share many of the same pathogens, some of which are zoonotic. We analyzed bobcat, puma, and feral domestic cat samples collected from targeted geographic areas. We examined exposure to three pathogens that are taxonomically diverse (bacterial, protozoal, viral), that incorporate multiple transmission strategies (vector-borne, environmental exposure/ingestion, and direct contact), and that vary in species-specificity. Bartonella spp., Feline Immunodeficiency Virus (FIV), and Toxoplasma gondii IgG were detected in all three species with mean respective prevalence as follows: puma 16%, 41% and 75%; bobcat 31%, 22% and 43%; domestic cat 45%, 10% and 1%. Bartonella spp. were highly prevalent among domestic cats in Southern California compared to other cohort groups. Feline Immunodeficiency Virus exposure was primarily associated with species and age, and was not influenced by geographic location. Pumas were more likely to be infected with FIV than bobcats, with domestic cats having the lowest infection rate. Toxoplasma gondii seroprevalence was high in both pumas and bobcats across all sites; in contrast, few domestic cats were seropositive, despite the fact that feral, free ranging domestic cats were targeted in this study. Interestingly, a directly transmitted species-specific disease (FIV) was not associated with geographic location, while exposure to indirectly transmitted diseases – vector-borne for Bartonella spp. and ingestion of oocysts via infected prey or environmental exposure for T. gondii – varied significantly by site. Pathogens transmitted by direct contact may be more dependent upon individual behaviors and intra-specific encounters. Future studies will integrate host density, as well as landscape features, to better understand the mechanisms driving disease exposure and to predict zones of cross-species pathogen transmission among wild and domestic felids

Carbon-sensitive pedotransfer functions for plant available water

Currently accepted pedotransfer functions show negligible effect of management-induced changes to soil organic carbon (SOC) on plant available water holding capacity (θAWHC), while some studies show the ability to substantially increase θAWHC through management. The Soil Health Institute\u27s North America Project to Evaluate Soil Health Measurements measured water content at field capacity using intact soil cores across 124 long-term research sites that contained increases in SOC as a result of management treatments such as reduced tillage and cover cropping. Pedotransfer functions were created for volumetric water content at field capacity (θFC) and permanent wilting point (θPWP). New pedotransfer functions had predictions of θAWHC that were similarly accurate compared with Saxton and Rawls when tested on samples from the National Soil Characterization database. Further, the new pedotransfer functions showed substantial effects of soil calcareousness and SOC on θAWHC. For an increase in SOC of 10 g kg–1 (1%) in noncalcareous soils, an average increase in θAWHC of 3.0 mm 100 mm–1 soil (0.03 m3 m–3) on average across all soil texture classes was found. This SOC related increase in θAWHC is about double previous estimates. Calcareous soils had an increase in θAWHC of 1.2 mm 100 mm–1 soil associated with a 10 g kg–1 increase in SOC, across all soil texture classes. New equations can aid in quantifying benefits of soil management practices that increase SOC and can be used to model the effect of changes in management on drought resilience

Linking soil microbial community structure to potential carbon mineralization: A continental scale assessment of reduced tillage

Potential carbon mineralization (Cmin) is a commonly used indicator of soil health, with greater Cmin values interpreted as healthier soil. While Cmin values are typically greater in agricultural soils managed with minimal physical disturbance, the mechanisms driving the increases remain poorly understood. This study assessed bacterial and archaeal community structure and potential microbial drivers of Cmin in soils maintained under various degrees of physical disturbance. Potential carbon mineralization, 16S rRNA sequences, and soil characterization data were collected as part of the North American Project to Evaluate Soil Health Measurements (NAPESHM). Results showed that type of cropping system, intensity of physical disturbance, and soil pH influenced microbial sensitivity to physical disturbance. Furthermore, 28% of amplicon sequence variants (ASVs), which were important in modeling Cmin, were enriched under soils managed with minimal physical disturbance. Sequences identified as enriched under minimal disturbance and important for modeling Cmin, were linked to organisms which could produce extracellular polymeric substances and contained metabolic strategies suited for tolerating environmental stressors. Understanding how physical disturbance shapes microbial communities across climates and inherent soil properties and drives changes in Cmin provides the context necessary to evaluate management impacts on standardized measures of soil microbial activity

New genetic loci link adipose and insulin biology to body fat distribution.

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

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Abstract Unsteady, high Reynolds number validation cases for a multi-phase CFD analysis tool have been pursued. The tool, designated UNCLE-M, has a wide range of applicability including flows of naval relevance. This includes supercavitating and cavitating flows, bubbly flows, and water entry flows. Thus far the tool has been applied to a variety of configurations. Axisymmetric sheet cavity flow-fields have been modeled. In particular, an attempt to validate the unsteady reliability of UNCLE-M with consideration of the effect of cavitation number, Reynolds number and turbulence model has been made. Analysis of the modeled unsteady flow-field is also made and conclusions regarding the causes of success and shortcomings in the computational results are drawn