This study addresses the degradation of shrub ecosystems and emphasizes the essential role that shrubs play within ecological systems. The use of advanced technological methods to swiftly and accurately capture information on shrub disturbance is crucial for preserving ecological security.
Utilizing the LandTrendr temporal segmentation algorithm on the Google Earth Engine cloud platform, and grounded in land cover data, we conducted dynamic monitoring of shrubland change across the Qinghai–Tibet Plateau from 1990 to 2022.
From 1990 to 2022, the cumulative total area of shrub disturbance in the Qinghai–Tibet Plateau amounted to 372.23 km2, primarily concentrated in the eastern and southeastern regions, with an overall decreasing trend observed. The duration of shrub disturbance was predominantly concentrated within a 1–2-year period, covering approximately 80.43% of the total disturbed area. Pixel-scale validation indicated an overall accuracy of 95.71%, with a Kappa coefficient of 0.93. User's accuracy for each year surpassed 73.82% and producer's accuracy was above 70.08%. Shrub disturbance on the Tibetan Plateau is mainly concentrated in areas with an altitude of 2000–4000 m, a slope gradient of 15°−40°, and a shady slope aspect. Shrub disturbance shows a moderately significant negative correlation with temperature (r = −0.436, p < 0.05) and a weakly significant positive correlation with precipitation (r = 0.124, p < 0.05), respectively.
Incorporating contextual data, the study identified climate, and topography as primary factors driving shrub disturbance. This study offers valuable scientific evidence and methodological references for monitoring large-scale shrub dynamics.
Autotoxicity is a type of intraspecific allelopathy in which compounds released by a plant inhibit the growth of other plants of the same species. In alfalfa (Medicago sativa L.), an herbaceous perennial legume widely used in hay and pasture production, autotoxicity is associated with re-establishment failure, reduced yields, and decreased persistence. Several compounds in the phenolic and saponin groups are suspected to contribute to alfalfa autotoxicity, but the exact compounds, ratio of compounds, and concentration of compounds necessary for autotoxicity are not fully defined. Symptoms of autotoxicity, including decreased germination and inhibited root elongation, are consistently observed in laboratory bioassays, but evidence to consistently implicate autotoxicity in poor alfalfa growth at field scale is lacking. This review article presents three criteria that address the production and accumulation of autotoxic compounds in alfalfa and distinguish symptoms of autotoxicity from other inhibitory factors in the field. These criteria provide a useful framework to highlight both competencies and gaps in our current understanding of alfalfa autotoxicity.
Fructan content and flux in temperate forages can benefit the grasses through increased cold hardiness, increased drought tolerance, and improved forage quality. Orchardgrass (Dactylis glomerata L., or cocksfoot) produces relatively long and unbranched levan-type fructans, but the genes involved in their biosynthesis are uncharacterized.
Through the evaluation of five orchardgrass cultivars and breeding lines that differ in their cold hardiness and freezing tolerance, we tested fructan and monosaccharide accumulation upon cold acclimation. The glycoside hydrolase-32 (GH32) gene family members involved in fructan biosynthesis were identified and grouped with homologous genes from Triticum aestivum and Lolium perenne.
In each of four GH32 gene families, there were specific genes with high transcript levels and no deletions in GH32 motifs. The candidate for sucrose:fructan 6-fructosyltransferase (6-SFT) exhibited the highest transcript levels of any GH32 gene in this study and was induced upon cold acclimation. Conversely, three invertase and two fructan exohydrolase genes, with roles in sucrose and fructan hydrolysis, had reduced transcript levels upon cold acclimation.
These data provide putative roles of GH32 genes in orchardgrass, and show that 6-SFT, vacuolar invertase (VI), and fructan exohydrolases (FEH) genes play a role in fructan biosynthesis and metabolism for cold acclimation in orchardgrass.
To optimize animal production systems for future sustainability, research now focuses on improving feed quality to enhance livestock performance. Here, we test the impact on goat metabolism of varying leaf proportions in the alfalfa component of an alfalfa–maize diet.
In a pen-feeding experiment, 16 three-month-old goats were divided into eight groups, four of which were fed a ration containing 40% alfalfa with leaves intact (LI) and four of which were fed an otherwise identical diet containing stemmy alfalfa (leaves removed, LR).
As expected, LR reduced protein intake compared to LI (48.3 vs. 93.3 g d−1; p < 0.001) and increased acid detergent fiber intake (239 vs. 167 g d−1; p < 0.001), but neutral detergent fiber and dry matter digestibility did not differ between LR and LI. The LR group had lower gross energy, digestible energy, and metabolizable energy intakes than the LI group (p = 0.080, 0.030, and 0.022, respectively). Retained nitrogen for LI and LR was 2.30 and 1.72 g d−1, respectively. Body weight gain was 74 g d−1 in LI and 52 g d−1 in LR (p < 0.001).
These results highlight that even where alfalfa is only one component of a mixed diet, the nutritive quality and leaf content of the alfalfa component are important to animal performance.
This research aimed to elucidate the components of rainfall variation, their influence on the natural vegetation growing season and consequent impacts on the livestock population.
This study evaluates the influence of rainfall metrics and drought on vegetation and livestock in Central District, Botswana. It uses Pearson correlation analysis to assess the relationships between rainfall metrics, drought, vegetation and livestock. Trends were analysed using Mann–Kendal and Sen's slope analysis.
It was found that rainfall variability and drought frequently occur in Central District, with continuing effects on vegetation and livestock. From 1990 to 2020, the district experienced moderate droughts on cycles of approximately alternating years. Severe drought occurred in 2003, and 2000 was a wet year. No significant trend was observed in rainfall metrics. The normalised difference vegetation index (NDVI), and the number of cattle and goats significantly declined. Annual NDVI shows a significant relationship with the number of rainy days, drought and consecutive wet days; cattle numbers are negatively correlated with consecutive dry days. Seasonal results show that NDVI is highly correlated to the number of rainy days in April–June (AMJ) and October–December, and NDVI is correlated to the standardised precipitation evapotranspiration index (SPEI) during AMJ and July–September.
The study findings revealed a seasonal and annual relationship between rainfall metrics, SPEI 12, livestock (goats, sheep and cattle population) and NDVI in the Central District of Botswana.
In West African semi-arid areas, grazing ecosystems are exposed to severe anthropogenic and climatic pressures. However, little is known about the contribution of local land management practices to increasing herbaceous forage in semi-arid environments. To recommend sustainable practices, this study therefore assessed the effect of three land management types on the diversity, functional structure and forage provision of the herbaceous vegetation in the Great Green Wall in Burkina Faso.
Floristic diversity, functional structure and the aboveground biomass of the herbaceous vegetation were assessed in 60 plots across three land management types, including fenced land (less disturbed), community forest (moderately disturbed) and fallow land (highly disturbed).
The herbaceous vegetation species richness increased with disturbance, where fenced land (71 species) had lower richness than community forest (95 species) and fallow land (103 species). The dominant life forms in each land management type were therophytes (fenced land: 75.73%, community forest: 78.87% and fallow land: 77.89%). The average cover of grasses (p < 0.001) and forbs (p = 0.049) varied significantly and showed a trend opposite to that of anthropogenic pressure. However, the net pastoral value (p = 0.002) and the total biomass (p < 0.001) decreased significantly according to the disturbance gradient. The net pastoral value ranged from 32.83% in fenced land to 27.69% in fallow land. The total biomass was higher in fenced land (1317 kg ha−1) than in community forest (1205 kg ha−1) and fallow land (1009 kg ha−1).
This study highlights an increase in herbaceous vegetation diversity, which is offset by a decline in the pastoral value of the grazing lands across the disturbance gradient.
Life cycle assessment (LCA) serves as an essential tool for the quantitative evaluation of production efficiency, environmental impacts, and sustainability across the entire life cycle of grass-based agricultural systems. This study systematically examines the progress of LCA applications in grass-based agriculture, analyzes the shortcomings of current methods, and proposes a new LCA approach based on an economic, social, and environmental multidimensional framework. The study emphasizes (1) the selection of LCA methods should align with specific research objectives, focusing not only on environmental impacts but also comprehensively considering social impacts and economic benefits; (2) it provides a comprehensive overview with an expanded scope selection beyond the “from cradle to farm gate” boundary and uses product value as the functional unit to facilitate assessments across various crop types, particularly focusing on inventory analysis and impact assessment; (3) challenges including model integration, impact sensitivity, and data uncertainty persist in the LCA of grass-based agriculture; and (4) multidimensional frameworks effectively integrate both quantitative and qualitative factors into grass-based agriculture, further enhancing the understanding of LCA results and supporting decision-making. Addressing these challenges through the integration of LCA with other models facilitates the sustainable evolution of grass-based agriculture, ensuring its long-term viability.
Meadow fescue (Schedonorus pratensis (Huds.) P. Beauv.) is a reemerging pasture grass for temperate regions of North America. One disadvantage of this species is its lack of tolerance to frequent defoliation at low residual sward heights. This experiment was designed to conduct one cycle of selection and evaluation for persistence under frequent defoliation.
The experiment included four locations with intensive grazing: two on silt loam soils and two on loamy sand soils. A fifth location was managed with frequent mowing to a 5-cm residual sward height, approximately 12–15 mowings per year. One cycle of selection was conducted with a population size of 1000 plants and 20 plants were selected for survivorship and vigor. Seed of all selected populations was evaluated at all five selection locations.
Gains were made in all eight populations, both due to increases in endophyte infection frequency and genetic gains associated with improved host genotypes. Selection was successful on both silt loam and loamy sand soils, but none of those gains were realized on the alternate soil type. Selection was successful at two of the four grazing farms, the two located on silt loam soils, but these gains were not realized on the farms with loamy sand soils or under the frequent mowing method of defoliation.
Selection for tolerance to intensive grazing should be conducted under grazing conditions and selection for adaptation to both sandy and silt loam soils will require a more complex and imaginative selection scheme.
The persistence of summer-active perennial species is critical for pasture-fed meat production in the temperate, uniform rainfall environment of south-eastern Australia.
To investigate the limitations of important pasture species under contrasting levels of drought and soil acidity stress, we monitored replicated field plots for persistence and productivity at three sites on the Southern Tablelands over 2–3 years.
All sites experienced a period of severe drought. At one site, persistence was ranked lucerne > phalaris > Porto cocksfoot > Savvy cocksfoot, tall fescue, chicory > plantain, red clover. Bromes survived via recruitment. Lucerne and chicory were the most productive immediately post-drought in summer and phalaris and chicory in autumn. Cocksfoot outyielded tall fescue. At a higher-elevation site, less drought-tolerant species were more persistent and productive. At a site with deep soil acidity, lucerne failed to persist; chicory performed better but declined with overgrazing during drought. Tall fescue declined severely during drought.
Lucerne remains the most productive summer option if soil conditions allow its growth, with chicory a potential replacement on acidic soils. Good productivity combined with acid soil tolerance favours cocksfoot over tall fescue. The ability to survive occasional severe drought is an important factor in species choice.
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