David J. Augustine

United States Department of Agriculture | USDA · Agricultural Research Service (ARS)

Long‐term research is essential for guiding the development of agroecosystems to meet escalating production demands in a manner that is environmentally sound and socially acceptable. Research must integrate biophysical and socioeconomic factors to provide geographically scalable knowledge that involves stakeholders across the research‐education‐ext...

The accurate estimation of aboveground net herbaceous production (ANHP) is crucial in rangeland management and monitoring. Remote and rural rangelands typically lack direct observation infrastructure, making satellite-derived methods essential. When ground data are available, a simple and effective way to estimate ANHP from satellites is to derive...

Study steers at the Central Plains Experimental Range, Nunn, Colorado

Semiarid rangelands throughout the western Great Plains support livestock production and many other ecosystem services. The degree to which adaptive multi‐paddock (AMP) grazing management approaches can help achieve desired ecosystem services remains unclear. At the Central Plains Experimental Range in northeastern Colorado, a management‐science pa...

Questions Grasslands provide important provisioning services worldwide and their management has consequences for these services. Management intensification is a widespread land‐use change and has accelerated across North America to meet rising demands on productivity, yet its impact on the relationship between plant diversity and productivity is st...

Rangelands are the dominant land use across a broad swath of central North America where they span a wide gradient, from <350 to >900 mm, in mean annual precipitation. Substantial efforts have examined temporal and spatial variation in aboveground net primary production (ANPP) to precipitation (PPT) across this gradient. In contrast, net secondary...

Adaptive multi-paddock (AMP) grazing is hypothesised to improve livestock diet quality by allowing managers to move livestock among paddocks in a manner that tracks phenological variation in forage growth related to variation in plant community composition. We compared yearling steer (Bos taurus) dietary crude protein (CP), digestible organic matte...

Burrowing rodents have unusually disproportionate effects on rangeland ecosystems because they (1) engineer their environment through burrow construction and modification of vegetation structure, (2) influence ecosystem processes including aboveground plant production, nutrient cycling rates, and water infiltration patterns, (3) alter plant communi...

Sustainable management of grazinglands depends upon understanding how management practices influence livestock movements in space and time. We conducted a ranch-scale (2,600-ha) social-ecological experiment to examine how foraging behavior of cattle differs between a single large herd rotated adaptively among paddocks (collaborative, adaptive range...

Understanding the chemical composition of our planet's crust was one of the biggest questions of the 20th century. More than 100 years later, we are still far from understanding the global patterns in the bioavailability and spatial coupling of elements in topsoils worldwide, despite their importance for the productivity and functioning of terrestr...

Infectious diseases pose a significant threat to global health and biodiversity. Yet, predicting the spatiotemporal dynamics of wildlife epizootics remains challenging. Disease outbreaks result from complex nonlinear interactions among a large collection of variables that rarely adhere to the assumptions of parametric regression modeling. We adopte...

Habitat loss and changing climate have direct impacts on native species but can also interact with disease pathogens to influence wildlife communities. In the North American Great Plains, black‐tailed prairie dogs (Cynomys ludovicianus) are a keystone species that create important grassland habitat for numerous species and serve as prey for predato...

A potential mechanism for lower livestock weight gains with rotational grazing is the additional movement and associated energy expenditures incurred with rotation of animals among paddocks. We evaluated these metrics in 2016 and 2017 using pedometers affixed to free-ranging naïve yearling steers grazing semiarid, shortgrass steppe under contrastin...

Prairie dogs and livestock have long been viewed as competitors for forage resources, causing widespread exterminations of prairie dogs, resulting in the decline of other threatened and endangered wildlife species. In this study we model the impacts that prairie dogs exhibit on the long-term profitability and cow herd dynamics of a ranch over a 40-...

On the Ground •Grazing management for providing multiple ecosystem services at the ranch scale requires balancing desired outcomes. •Abundant challenges involve matching the spatial heterogeneity in soils and associated plant community characteristics with the temporal variability in precipitation. •Prescriptive grazing (season-long continuous and...

On the Ground •The combination of stocking rate and marketing date that maximizes average net return per head will not necessarily maximize average net return per hectare. •The combination of stocking rate and marketing date that maximizes average net return per hectare often comes with risk-related tradeoffs, such as a higher risk and magnitude o...

Context Technologies are now available to continuously monitor livestock foraging behaviours, but it remains unclear whether such measurements can meaningfully inform livestock grazing management decisions. Empirical studies in extensive rangelands are needed to quantify relationships between short-term foraging behaviours (e.g. minutes to days) an...

Black-tailed prairie dogs (Cynomys ludovicianus) exhibit boom and bust cycles in landscapes where they are affected by outbreaks of plague caused by the introduced bacterium Yersinia pestis. We examined spatiotemporal dynamics of black-tailed prairie dog colonies in the Thunder Basin National Grassland, Wyoming over a period of 21 years. The colony...

Quantifying spatial and temporal fluxes of phosphorus (P) within and among agricultural production systems is critical for sustaining agricultural production while minimizing environmental impacts. To better understand P fluxes in agricultural landscapes, P‐FLUX, a detailed and harmonized dataset of P inputs, outputs, and budgets, as well as estima...

Plant communities in rangeland ecosystems vary widely in the degree to which they can compensate for losses to herbivores. Ecosystem‐level factors have been proposed to affect this compensatory capacity, including timing and intensity of grazing, and availability of soil moisture and nutrients. Arid ecosystems are particularly challenging to predic...

Quantifying spatial and temporal fluxes of phosphorus (P) within and among agricul- tural production systems is critical for sustaining agricultural production while min- imizing environmental impacts. To better understand P fluxes in agricultural land- scapes, P-FLUX, a detailed and harmonized dataset of P inputs, outputs, and budgets, as well as...

We used a long-term herbivore removal experiment where paired exclosure–open treatments were established at the Mpala Research Centre, Laikipia, Kenya, in 1999 to examine changes in soil nitrogen (N) at nutrient-rich glades and adjacent nutrient-poor bushland sites after almost two decades of herbivore removal. Glades in this landscape are created...

Adaptive management requires rangeland managers to respond to changing forage conditions (e.g., standing herbaceous biomass) within the grazing season at the scale of individual pastures. While within-season biomass can be measured or estimated in the field, it is often impractical to make field measurements in extensive rangeland systems with adeq...

Rotational grazing studies have produced mixed results related to animal performance (weight gain), which has contributed to producer uncertainty regarding grazing management decisions. To enhance decision-support for producers, we improved algorithms in the Agricultural Policy/Environmental eXtender (APEX) model to better represent cattle weight g...

In the Great Plains of central North America, sustainable livestock production is dependent on matching the timing of forage availability and quality with animal intake demands. Advances in remote sensing technology provide accurate information for forage quantity. However, similar efforts for forage quality are lacking. Crude protein (CP) content...

Research in progress poster

Adaptive management of large herbivores requires an understanding of how spatial‐temporal fluctuations in forage biomass and quality influence animal performance. Advances in remote sensing have yielded information about the spatial‐temporal dynamics of forage biomass, which in turn have informed rangeland management decisions such as stocking rate...

Coverage of living (green) vegetation influences rangeland processes and biodiversity but remains a challenge to quantify at small spatial grain. We describe a technique for rapid airborne (unmanned aerial vehicle) measurements of continuous spatial coverage of living vegetation at a resolution (spatial grain) of 8 cm ground sampling distance. We t...

Rangelands are composed of patchy, highly dynamic herbaceous plant communities that are difficult to quantify across broad spatial extents at resolutions relevant to their characteristic spatial scales. Furthermore, differentiation of these plant communities using remotely sensed observations is complicated by their similar spectral absorption prof...

Significance Declines of wild megafauna are expected to transform ecosystems and are known to influence tree–grass balance in African savannas, but the effects of large herbivores on lianas are unknown. Using diet analysis, long-term exclosure experiments, and smaller-scale manipulations, we show that liana infestation occurred rapidly after the lo...

Grassland birds have experienced some of the steepest population declines of any guild of birds in North America. The shortgrass steppe contains some of North America’s most intact grasslands, which makes the region particularly important for these species. It is well known that grassland birds differentially respond to variation in vegetation stru...

State-and-transition models (STMs) are tools used in rangeland management to describe linear and nonlinear vegetation dynamics as conceptual models. STMs can be improved by including additional ecosystem services, such as wildlife habitat, so that managers can predict how local populations might respond to state changes and to illustrate the tradeo...

Frequent, severe defoliation reduces grass production and can alter plant species composition in grasslands. Multipaddock rotational grazing has been proposed as a grazing strategy that may reduce the frequency and intensity of defoliation on palatable grass plants without altering stocking rates. Previous studies evaluated this hypothesis using sm...

Advances in on-animal sensor technologies to monitor location and activity have enhanced the ability to study foraging decisions of free-ranging herbivores. Sensors monitoring jaw movements that quantify ingestive behaviours, such as the RumiWatch (RW) noseband sensor system, have primarily been used in indoor animal housing systems or structurally...

The conservation and management of black‐tailed prairie dogs (Cynomys ludovicianus) have been contentious issues in grasslands of central North America for much of the past century, primarily because of the perception that they compete with livestock for forage. Studies quantifying the magnitude of competition between prairie dogs and cattle are di...

Context Understanding how grazing management decisions influence the productivity and composition of rangeland plant communities is essential for the development of effective strategies to sustainably produce multiple ecosystem goods and services. Informed with experimental measurements, simulation models can advance our understanding and stewardsh...

On the Ground •Adaptive management should explicitly involve stakeholders, emphasize multiple iterations of identifying and prioritizing outcomes, and tightly link science-informed monitoring to decision-making benchmarks for effective feedback loops. •Short-term monitoring procedures should be simple, quick, and based on consistent methods that a...

On the Ground •As “co-produced” research becomes more popular, there is a need to evaluate the processes and outcomes of successful cases. •The Collaborative Adaptive Rangeland Management project is a case of a ranch-scale, 10-year grazing experiment ongoing in Colorado. We used social science to evaluate group learning. •We describe the complex,...

Livestock distribution in extensive rangelands of North America can present management challenges to land managers. Understanding the role of topography on livestock distribution, within and across diverse rangeland ecosystems, could provide land managers valuable information for adaptive management of livestock to address both conservation and pro...

Collaborative adaptive management (CAM) is hypothesized to benefit management of rangeland ecosystems, but the presumed benefits have seldom been quantified, and never in a multipaddock rotational grazing system. Here, we evaluated average daily weight gain (ADG) of livestock (kg steer⁻¹ d⁻¹) in four grazing management treatments during the summers...

Abstract Aboveground net primary productivity (ANPP) in grasslands is an important integrator of terrestrial ecosystem function, a key driver of global biogeochemical cycles, and a critical source of food for wild and domesticated herbivores. ANPP exhibits high spatial and temporal variability, driven by a suite of factors including precipitation a...

Livestock distribution in extensive rangelands of North America can present management challenges to land managers. Understanding the role of topography on livestock distribution, within and across diverse rangeland ecosystems, could provide land managers valuable information for adaptive management of livestock to address both conservation and pro...

Bement (1969) developed a stocking rate (SR) guide for yearling cattle grazing shortgrass steppe based on relationships among average daily weight gain (ADG, kg · d −1), beef production per hectare (BP, kg · ha −1), and stocking rate (animal unit days, AUD · ha −1) measured in long-term grazing experiments conducted from 1940 to 1963. These analyse...

Despite progress in trait‐based ecology, there is limited understanding of the plant traits that structure semi‐arid grasslands. In particular, it remains unclear how traits that enable plants to cope with water limitation are related to traits that influence other key functions such as herbivore defence and growth. The hypothesis that drought and...

Questions What are the rate, reversibility, and degree of symmetry in plant species compositional change in response to the addition and removal of cattle grazing in the shortgrass steppe? Specifically, how does the imposition and removal of grazing affect the abundance of perennial C4 shortgrasses and C3 midgrasses that are of primary importance f...

A comprehensive understanding of multipaddock, rotational grazing management on rangelands has been slow to develop, and the contribution of adaptive management (Briske et al. 2011) and sufficient scale (Teague and Barnes 2017) have been identified as key omissions. We designed an experiment to compare responses of vegetation and cattle in an adapt...

North American sagebrush ( Artemisia spp.)‐obligate birds are experiencing steep population declines due in part to increased disturbance, mainly human‐caused, across their range. At the eastern edge of the sagebrush steppe, this issue may potentially be exacerbated because of natural disturbance by black‐tailed prairie dogs ( Cynomys ludovicianus...

Habitat loss and altered disturbance regimes have led to declines in many species of grassland and sagebrush birds, including the imperiled Mountain Plover (Charadrius montanus). In certain parts of their range Mountain Plovers rely almost exclusively on black-tailed prairie dog (Cynomys ludovicianus) colonies as nesting habitat. Previous studies h...

Knowledge of climatic and management influences on large herbivore production (LHP, kg ha⁻¹) is needed for low productivity, semiarid grasslands to address potential consequences of both increasing climate variability and the need to increase animal protein for human consumption. Here, we evaluate the influence of climatic variability and herbivore...

Although studies have shown that mammalian herbivores often limit aboveground carbon storage in savannas, their effects on belowground soil carbon storage remain unclear. Using three sets of long‐term, large herbivore exclosures with paired controls, we asked how almost two decades of herbivore removal from a semiarid savanna in Laikipia, Kenya aff...

Rangeland ecosystems worldwide are characterized by a high degree of uncertainty in precipitation, both within and across years. Such uncertainty creates challenges for livestock managers seeking to match herbivore numbers with forage availability to prevent vegetation degradation and optimize livestock production. Here, we assess variation in annu...

A network to understand the changing socio-ecology of the southern African woodlands (SEOSAW): Challenges, benefits, and methods The SEOSAW partnership* This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly ci...

Grazing land models can assess the provisioning and trade-offs among ecosystem services attributable to grazing management strategies. We reviewed 12 grazing land models used for evaluating forage and animal (meat and milk) production, soil C sequestration, greenhouse gas emission, and nitrogen leaching, under both current and projected climate con...

Rangelands are temporally and spatially complex socioecological systems on which the predominant land use is livestock production. In North America, rangelands also contain approximately 80% of remaining habitat for grassland birds, a guild of species that has experienced precipitous declines since the 1970s. While livestock grazing management may...

As anthropogenic influences on the world’s rangelands accelerate, there is an urgency for humanity to develop a greater understanding of key drivers, and processes, underlying ecological dynamics and function, to inform improved management strategies. Browsing and grazing ungulates are important components of human-dominated and natural ecosystems,...