Climate change and variability impacts on grazing herds: Insights from a system dynamics approach for semi‐arid Australian rangelands

Abstract

Grazing livestock are an important source of food and income for millions of people worldwide. Changes in mean climate and increasing climate variability are affecting grasslands' carrying capacity, thus threatening the livelihood of millions of people as well as the health of grassland ecosystems. Compared with cropping systems, relatively little is known about the impact of such climatic changes on grasslands and livestock productivity and the adaptation responses available to farmers. In this study, we analysed the relationship between changes in mean precipitation, precipitation variability, farming practices and grazing cattle using a system dynamics approach for a semi‐arid Australian rangeland system. We found that forage production and animal stocking rates were significantly affected by drought intensities and durations as well as by long‐term climate trends. After a drought event, herd size recovery times ranged from years to decades in the absence of proactive restocking through animal purchases. Decreases in the annual precipitation means or increases in the interannual (year‐to‐year) and intra‐annual (month‐to‐month) precipitation variability, all reduced herd sizes. The contribution of farming practices versus climate effect on herd dynamics varied depending on the herd characteristics considered. Climate contributed the most to the variance in stocking rates, followed by forage productivity levels and feeding supplementation practices (with or without urea and molasses). While intensification strategies and favourable climates increased long‐term herd sizes, they also resulted in larger reductions in animal numbers during droughts and raised total enteric methane emissions. In the face of future climate trends, the grazing sector will need to increase its adaptability. Understanding which farming strategies can be beneficial, where, and when, as well as the enabling mechanisms required to implement them, will be critical for effectively improving rangelands and the livelihoods of pastoralists worldwide.

An Evaluation of Historical Trends in New Mexico Beef Cattle Production in Relation to Climate and Energy

“…At the same time, the US's Fourth National Climate Assessment highlighted an observed and projected decline in livestock production that was linked to climate change impact through resources consumption (e.g., water and energy) and degradation (pasture land) [6]. Unless there is a clear understanding of the factors affecting this industry coupled with a science-based balanced vision about its impact on climate, enhancing the sustainability of this industry would be a great challenge [7][8][9]. While accounting for beef industry as an individual system is important, this vision also highlighted the need to include and consider the integration of this system with the interconnected food-energy-water (FEW) systems [10].…”

“…Therefore, the beef cattle industry is connected with the other sectors that include water [21], crops, labor, machineries, equipment, vehicles [22], and energy [16]. These interconnected sectors further highlighted the need to consider the livestock production system (including beef industry) within integrated FEW systems [8,10,23]. Within this context, this analysis was aimed to understand the behavior of beef cattle industry and environmental changes.…”

“…Research is lacking on proper characterization of the relationships between the beef cattle system and water-energy systems which can negatively affect the development of sustainable production systems [8,44]. Providing such characterization not only can potentially help in improving the sustainability of the overall food production but also FEW systems.…”

Historical Trends in New Mexico Forage Crop Production in Relation to Climate, Energy, and Rangelands

“…These initial results, however, also suggested that there can be a relationship (i.e., correlation) between mean annual precipitation and mean annual range conditions that can directly or indirectly affect their corresponding individual relationships with hay prices [11,59,60]. A regression analysis was conducted to evaluate the significance of this relationship between these two predictors (i.e., mean annual precipitation and mean annual range conditions) and it was found to be significant at P ≤ 0.05 with R 2 = 0.52.…”

Potential and restrictions of Poincianella pyramidalis (Tul.) L. P. Queiroz as native forage in the Brazilian semi-arid region

“…Studies relating to rainfall input and the nutritional aspects of forage plants could result in tools that would help in the better management and use of these plants by the animals (Godde et al, 2019;Habermann et al, 2019;Hui et al, 2018). Aspects of the nutritional potential of the plant were studied by Gonzaga Neto et al (2001), andMendonça Júnior, Braga, andGalvão (2008) and there are many studies of the pharmacological and medicinal potential of the species due to the presence of biflavanoids and other compounds (Oliveira, David, & David, 2016a).…”