Vegetation Response to Goats Grazing Intensity in Semiarid Hilly Grassland of the Loess Plateau, Lanzhou, China

Abstract

Quantitatively estimating the grazing intensity (GI) effects on vegetation in semiarid hilly grassland of the Loess Plateau can help to develop safe utilization levels for natural grasslands, which is a necessity of maintaining livestock production and sustainable development of grasslands. Normalized difference vegetation index (NDVI), field vegetation data, and 181 days (one goat per day) of GPS tracking were combined to quantify the spatial pattern of GI, and its effects on the vegetation community structure. The spatial distribution of GI was uneven, with a mean value of 0.50 goats/ha, and 95% of the study area had less than 1.30 goats/ha. The areas with utilization rates of rangeland (July) lower than 45% and 20% made up about 95% and 60% of the study area, respectively. Grazing significantly reduced monthly aboveground biomass, but the grazing effects on plant growth rate were complex across the different plant growth stages. Grazing impaired plant growth in general, but the intermediate GI appeared to facilitate plant growth rate at the end of the growing seasons. Grazing had minimal relationship with vegetation community structure characteristics, though Importance Value of forbs increased with increasing GI. Flexibility in the number of goats and conservatively defining utilization rate, according to the inter-annual variation of utilization biomass, would be beneficial to achieve ecologically healthy and economically sustainable GI.

The Nitrogen Cycling Key Functional Genes and Related Microbial Bacterial Community α−Diversity Is Determined by Crop Rotation Plans in the Loess Plateau

“…Diversity of Shannon index and richness index (Chao1, ACE) were calculated using "phyloseq" package [48]. Nonlinear regression and spearman correlation analyses were performed using the "survival" and "basicTrendline" packages, respectively [49]. Heatmaps were used to illustrate the Z-score-normalized relative abundance of N-cycling functional genes using the "pheatmap" package [50].…”

Distribution of Grazing Paths and Their Influence on Mountain Vegetation in the Traditional Grazing Area of the Tien-Shan Mountains

“…In July 2022, during the field survey, sixty samples (Figure 1) were set up in areas with typical grazing path distribution based on the distribution characteristics of grazing behavior and other factors, including accessibility and terrain (Figure 1), which were evenly distributed on the hilltop (No. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20], hillside (No. [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40], and hillbottom (No.…”

“…Grazing paths are diverse, with primarily parallel, oblique, and grid patterns [14]. In contrast, in areas with high slopes, animals move at a lower rate, so the density and tortuosity of grazing paths are greater [15]. Zhang [16] found that grazing has an influential effect on the structure of plant communities, with foraging and trampling by goats reducing plant density as well as cover.…”

UAV Assisted Livestock Distribution Monitoring and Quantification: A Low-Cost and High-Precision Solution

“…Unlike the designed experiments, GD under real-world conditions have rarely been quantified because of the limitations of efficient monitor technology and available data. Some studies have focused on quantifying GD through vegetation indices and ground observation visually or by using time-lapse cameras [15][16][17], while some other researchers have attempted to quantify GD only by the remote sensing indices [1,17,18]. However, these studies usually provide rough estimates based on some specific indicators, which may not be sufficient for precise and reasonable management of grassland.…”