Large shrubs partly compensate negative effects of grazing on hydrological function in a semi-arid savanna

A Global Synthesis of the Effects of Livestock Activity on Hydrological Processes

The livestock sector supports billions of people worldwide, yet when poorly managed, can have substantial negative effects on soils and ecosystem functions. Despite numerous studies and reviews of the effects of livestock activity on hydrological functions, a global synthesis of their effects on different biotic (vegetation, herbivore type) and abiotic (climate, soil, spatial scales) factors remains elusive. This makes it difficult to provide ecologically based advice on how best to manage grazing to minimise environmental damage and maximise hydrological functions. We used a global meta-analysis to examine the effects of livestock activity on hydrological inflows (infiltration, soil moisture), and outflows (runoff, sediment) using a dataset compiled from 3044 contrasts of grazed and ungrazed data from 129 publications between 1935 and 2020. Overall, we found that livestock activity increased sediment production (+ 52 ± 19.8%; mean ± 95% CI), reduced infiltration (− 25 ± 5.2%), but had no significant effect on either runoff (+ 27 ± 29.6%) or soil moisture (− 5 ± 5.9%). These impacts varied markedly among herbivore types and intensity, with greatest reductions in infiltration at high and low grazing contrasts, and more pronounced negative effects of grazing when sheep and cattle grazed together than either alone. The impact of livestock activity also varied with climatic region, soil texture, and the interaction between aridity and plant cover. Our study demonstrates the nuanced effects of livestock activity, with herbivore type and intensity, and environmental context modifying the hydrological outcomes. Livestock grazing is unlikely to result in positive environmental outcomes for infiltration and sediment production.

Effect of vegetation patchiness on the subsurface water distribution in abandoned farmland of the Loess Plateau, China

Patchiness of grassland results in important effects on ecohydrological processes in arid and semiarid areas; however, the influences on subsurface water flow and soil water distribution remain poorly understood, particularly during vegetation succession on slopes. This study examined these effects by comparing the water flow behaviors and preferential infiltration between vegetation patches (VP) and interspace patches (IP) in three sites at different states of vegetation succession (grass, subshrub and shrub) in abandoned farmland of the Loess Plateau, China. Dye tracer infiltration showed that patchiness of vegetation increased spatial variations of soil water and preferential infiltration by increasing the densities of fine root length and fine root volume in the soil profile. Moreover, the more abundant and intricate roots following a lateral direction beneath VP likely contributed to lateral flow and infiltration variability. However, differences between VP and IP were not significant because considerable living fine roots and decayed roots of IP also provided preferential flow pathways. Our finding indicated that IP could compete with VP for access to soil water resources, which potentially increased hillslope-scale infiltration and reduced surface runoff and erosion risk. Under the different states of vegetation succession, subshrub patches showed significantly greater preferential infiltration volume (28.53 mm) and contribution of preferential infiltration to total infiltration (60.58%) than grass and shrub patches. Vegetation patch size made positive effects on improving preferential flow and water movement. Greater preferential flow in subshrub patches played a positive role in soil water storage and replenishment. Therefore, natural restoration of a slope area with small heterogeneity in preferential flow can be successfully applied in the Loess Plateau, particularly during the subshrub succession state.

Grazing trajectory statistics and visualization platform based on cloud GIS

It is very important for ranchers and grassland livestock management departments to master the information on the trajectory and feeding behavior of the herd timely and accurately. Therefore, this study developed a statistics and visualization platform for grazing trajectory. The platform was implemented by using the Web AppBuilder for ArcGIS framework and ArcGIS Online server. In particular, the trajectory processing service on the server was used to calculate walking speed, walking trajectory and feed intake of the herd in the platform. And these results were published to the ArcGIS Online server. The relevant information was analyzed and displayed by Web AppBuilder for ArcGIS calling the data on ArcGIS Online. Moreover, the paltform provided some visualization functions to support the visualization of user-defined analysis results. When users use the functions of spatial analysis (such as buffer analysis, finding hot pots analysis and interpolation point analysis), they can choose to analyze spatial data and related field information to conduct customized spatial data analysis. In a short, the platform realized the visualization functions of feed intake statistics, walking speed statistics, spatial analysis, line chart analysis and pie chart analysis of spatial data related attributes. It can provide technical support and data support for the relevant management departments to monitor grazing information and study the living habits of the herd.