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Analysis of the characteristic changes in water use efficiency in alpine meadows and its influencing factors plays an important role in improving the water use efficiency of these alpine meadows. Our study used gross primary productivity (GPP) and evapotranspiration as calculated by the latent heat flux (LE) and the latent heat of evaporation (latent heat of evaporation, λ) to evaluate the water dynamics of Potentilla fruticosa shrub meadows in Haibei, Qinghai Province between 2003 and 2010. The water use efficiency (WUE) of these shrub meadows was evaluated across eight consecutive years, allowing for a robust evaluation of their response to meteorological factors. Our results showed the following: 1) On an interannual scale, the gross primary productivity, evapotranspiration, and water use efficiency increased at an annual rate of 98.55 g·m−2, 40.15 mm, and 138.70 g·(m2·mm)−1, respectively. While gross primary productivity, evapotranspiration, and water use efficiency all reached their maximum in July and their minimum in January when evaluated on a seasonal scale. 2) The annual average temperature, relative humidity, and net radiation have the highest relative contribution to the annual water use efficiency, and these factors can explain up to 73.50% of the variation in the annual water use efficiency values. The following three environmental factors: photosynthetically active radiation, air temperature, and relative humidity contribute as much as 74.14% to the values on the growth season scale. The annual average temperature and photosynthetically active radiation rates are both relatively important contributing factors to both the annual and growing season scales, with these values accounting for up to 43.09% and 30.79% of the total, respectively. Correlation analysis revealed that relative humidity was the main factor affecting water use efficiency. Annual average temperature and vapor pressure deficit also exerted some effect on the annual scale values under these conditions. The main influencing factors for the growing season scale also included photosynthetically active radiation and net radiation. The results of this study make a significant contribution toward clarifying the underlying regulatory mechanisms mediating the dynamic changes in water use efficiency in shrub meadows in response to changing environmental conditions.
This study aimed to provide a scientific basis for soil and water conservation in alpine shrub grasslands. The hydrological effects of grazing different livestock on the litter layer and soil layer of alpine shrub grassland were studied, including the moisture capacity, water holding rate, and interception amount of the litter layer and soil layer of grazing Gansu wapiti and mixed grazing yak and Tibetan sheep in the alpine shrubland in the Tianzhu alpine region of the eastern Qilian Mountains from July to August 2020. The result showed that the total litter thickness of the mixed grazing yak and Tibetan sheep plot (3.53 cm) was greater than the grazing Gansu wapiti plot (2.83 cm), and the total litter storage is expressed as the mixed yak Tibetan sheep plot (219.45 g·m−2) > the grazing Gansu wapiti plot (92.86 g·m−2) (P < 0.05); The average water holding capacity and initial water holding rate of litter in the mixed grazing yak and Tibetan sheep plot were higher than those in the grazing Gansu wapiti plot; the average maximum water holding capacity of litter is represented by the mixed grazing yak and Tibetan sheep plot (20.78 t∙ha−1) > the grazing Gansu wapiti plot (10.71 t∙ha−1), the average maximum water holding rate is represented by the mixed grazing yak and Tibetan sheep plot (221.00%) > the grazing Gansu wapiti plot (148.11%), and the average maximum interception is represented by the mixed grazing yak and Tibetan sheep plot (939.21 t∙ha−1) > the grazing Gansu wapiti plot (348.58 t∙ha−1), and the effective interception is shown as the mixed yak Tibetan Sheep plot (627.52 t∙ha−1) > the grazing Gansu wapiti plot (187.90 t∙ha−1) (P < 0.05). The soil moisture content of the shallow layer (0 – 40 cm) in the grazing Gansu wapiti plot between and under the shrubs were significantly higher than in the mixed grazing yak and Tibetan sheep plot, while the deep soil (40 – 100 cm) showed the opposite result; the bulk density of the 0 – 30 cm soil layer between shrub of the mixed grazing yak and Tibetan sheep plot > the grazing Gansu wapiti plot, the opposite of under shrub. The initial soil infiltration rate showed the grazing Gansu wapiti plot (10.98 mm∙min−1) > the mixed grazing yak and Tibetan sheep plot (6.92 mm∙min−1), and the steady infiltration rate also showed the grazing Gansu wapiti plot (7.12 mm∙min−1) > the mixed grazing yak and Tibetan sheep plot (5.90 mm∙min−1). To summarize; the mixed grazing of yak and Tibetan sheep is more conducive to water conservation and soil and water conservation in alpine shrubland.
Evaporation is severe in arid and semi-arid areas, and vegetation growth in these areas depends on the groundwater supply. The growth of the underground part of vegetation is limited by the depth of the groundwater table. To determine if the underground part of vegetation (root biomass), growth environmental factors (soil nutrients and pH), and their relationship are affected by the groundwater table depth, a controlled experiment with an increasing groundwater table depth (0.5, 1.0, and 2.0 m) was conducted in Horqin sandy grassland. The results were as follows: 1) soil total nitrogen, total phosphorus, and pH increased as the groundwater table depth changed in the control tests, and there were significant differences among the treatments (P < 0.05). However, the soil organic carbon content showed a downward trend, and there was no significant difference among the treatments. The soil organic carbon, total nitrogen, and total phosphorus contents all decreased as the groundwater table depth increased, whereas the pH increased as the soil depth increased, but the difference was not significant. 2) The root biomass decreased as the soil depth increased at different groundwater depths. 3) Soil organic carbon, total nitrogen, and total phosphorus were positively correlated with the root biomass, whereas the pH was not negatively correlated with the root biomass. Therefore, this study shows that different groundwater table depth treatments have different effects on different soil nutrient types, but the groundwater table depth in Horqin sandy grassland will accelerate the loss of soil organic carbon, total nitrogen, and total phosphorus contents and the increase in root biomass.
Salt stress can accelerate the rate of yellowing and affect the overall value of turfgrass. Although NAC transcription factors have been reported to play important roles in plant salt tolerance, only a few studies have described the functional characterization of NAC genes in Zoysia japonica. In this study, we used yeast strain YPH500 transformed with the ZjNAC3 gene to evaluate the contribution of this gene to salt stress tolerance. Our preliminary data determined that ZjNAC3 negatively regulates yeast cell growth during salt stress with this being further confirmed in a transgenic Arabidopsis thaliana treated with salt. Our analysis showed that the growth of these transgenic plants was significantly weaker than wild-type (WT) plants after 7 days of treatment with 150 mmol·L−1 NaCl. Proline, MDA content, and cell membrane permeability were also all significantly higher in ZjNAC3−overexpressing lines than in WT (P < 0.05), whereas chlorophyll and soluble sugar content was decreased in transgenic plants (P < 0.05). In addition, the expression of AtNHX1 in the transgenic lines was significantly lower than that in WT plants (P < 0.05). Taken together, these data indicate that the overexpression of the ZjNAC3 gene decreases salt tolerance in Arabidopsis plants. It is thus rational to deduce that the decline in osmotic regulation, severe cell damage, and weakened ability to isolate Na+ into vacuoles all contribute to the salt-sensitive phenotype of these transgenic Arabidopsis plants. This study revealed that ZjNAC3 is an important gene regulating salt stress tolerance and lays the foundation for the future exploration of NAC transcription factors in Zoysia japonica.
Grassland is an important part of terrestrial ecosystems, and its ecological environment is closely related to national ecological security. However, the grassland degradation in China is becoming more serious, with grassland area and yield decreasing yearly, which not only affects the economic development, but also triggers various environmental problems, such as soil erosion and desertification. Thus, there is an urgent need for good ecological grass species with strong resistance and wide adaptability, while adhering to the principle of natural restoration, to improve the current situation of grassland degradation and actively respond to environmental changes. Wild barley (Hordeum brevisubulatum) is widely distributed in salinized meadows in China. It has high yield, good quality, well-developed root system, drought and cold tolerance, barren tolerance, salt-alkali tolerance, and an improved resistance and adaptability to endophytic fungal infection. In addition to grazing, mowing, silage, grass meal processing, or hay modulation, there is a promising future in establishing cultivated grasslands in low wetlands and in improving saline soil. This study summarized the excellent characteristics of wild barley, its utilization value, and the influence of endophytic fungi on its growth, resistance, and competitiveness. This study also analyzed its potential as an ecological grass species. An in-depth study and rational use of wild barley-endophytic fungus symbionts provide a reference.
Alfalfa flowers are rich in anthocyanins, which can be used as food coloring agents. In this study, ultrasonic-assisted extraction was used to extract anthocyanins from alfalfa, and response surface methodology (RSM) was used to improve the extraction rate of these anthocyanins. These anthocyanins were then microencapsulated to improve their stability. Our results showed that the optimal extraction conditions for these compounds were as follows: 61% ethanol as extraction agent, liquid to solid ratio was 30 ꞉ 1, extraction temperature of 65 ℃, extraction time of 25 min, and ultrasonic power of 250 W. The use of these conditions produced a maximum anthocyanins content of 1.581 mg·g−1. Microcapsules wereprepared using maltodextrin, xanthan gum, and acacia gum as wall materials. The optimal wall material ratio was maltodextrin ꞉ xanthan gum = 30 ꞉ 1 (w : w), and the encapsulation rate was well. The microencapsulated anthocyanins were stable.
Anthracnose caused by Colletotrichum cereale is the main limiting factor in the production of oats (Avena sativa) in the northern Shanxi Province; however, no research has been carried out on the prevention and control of oat anthracnose using chemical fungicides. To clarify the inhibitory effects of fungicides with different mechanisms of action on oat anthracnose, 10 fungicides from six categories were selected and studied, and their antifungal effects were measured using the hyphae growth rate method and the droplet method. The results showed that carbendazim (50% wettable powder, WP), propiconazole (50% WP), azoxystrobin (25% suspension concentrates, SC), and pyraclostrobin (25% SC) had strong inhibitory effects on the growth of C. cereale hyphae, with EC50 (50% effective concentration) values of 0.0921, 0.8774, 0.1180, and 0.0029 mg·L−1, respectively. Chlorothalonil (75% WP), carbendazim (50% WP), azoxystrobin (25% SC), and pyraclostrobin (25% SC) had a strong inhibitory effect on the germination of C. cereale spores. For chlorothalonil (75% WP), when the concentration was ≥ 0.80 mg·L−1, the spore germination inhibition rate was 100%, and the EC50 of carbendazim (50% WP), azoxystrobin (25% SC), and pyraclostrobin (25% SC) were 0.1124, 0.1184, and 0.0059 mg·L−1. Based on the different mechanisms of action, it is recommended that chlorothalonil (75% WP) be used as a protective fungicide before anthracnose occurs, whereas carbendazim (50% WP), azoxystrobin (25% SC), and pyraclostrobin (25% SC) should be used as protective and therapeutic fungicides. In addition, producers should promptly rotate chemical fungicides with different mechanisms of action to prevent and control diseases, improve planting conditions, introduce and select disease-resistant varieties, and ensure the sustainable production of oats.
The use of calorific value as a measure of photosynthesis in plants and the ability of reducing sugars to directly supply energy to plants through redox reactions, both play an important role in plant regreening and regrowth. In this study, field sampling and laboratory analysis were used to analyze the calorific value, reducing sugar content, and dry matter weight of Stipa breviflora under different stocking rates; correlations between the variables were also assessed. Results showed that 1) Calorific value, reducing sugar content, and dry matter weight decreased consistently with increasing stocking rate. Heavy grazing also decreased significantly when compared with enclosure (P < 0.05). 2) Leaf calorific value and dry matter weight changed at a consistent rate throughout the study, with no variation between months; both increased significantly with time (P < 0.05). Reducing sugar content decreased initially and then increased. 3) There was a significant positive correlation between leaf calorific value and dry matter weight (P < 0.001), and a significant negative correlation (P < 0.05) between reducing sugar content and dry matter weight. These results demonstrate that enclosure promotes the transfer of energy from grasslands to S. breviflora and encourages growth and development, indicating its importance in maintaining and improving the desert grassland ecosystem.
The purpose of this study was to establish a near-infrared (NIR) prediction model for nutrient content in different parts (tissues) of silage corn using near-infrared spectroscopy (NIRS). Two hundred and twenty-seven silage corn samples were collected from Minqin County, Gansu Province. Near-infrared prediction models for dry matter (DM), organic matter (OM), crude protein (CP), ether extract (EE), neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL) contents in the different parts (tissues) of silage corn were established using the improved partial least squares (MPLS) method. There were three derivative treatments and ten spectral scattering treatments included in the model. The results showed that the coefficient of determination for validation (RSQv) and the ratio of performance to deviation for validation (RPD) of the ADF content prediction model were higher than those for other components, while RSQv and RPD for the NDF, CP, and OM contents were lower than those for ADF. The RSQv values for ADF, NDF, CP, and OM were all greater than 0.9, while the RPD was greater than 2.5, which means that they can be used for accurate analysis during actual production. The RSQv and RPD for EE content were 0.701 and 1.838, respectively, and the RSQv and RPD for DM and ADL were 0.525 and 1.549, and 0.631 and 1.602, respectively. These two models cannot be used in actual production and the models need to be further optimized. In conclusion, near infrared prediction models for ADF, NDF, CP, and OM contents in different parts (tissues) of silage corn were established, and these models can be applied to production practice.
The objective of this study was to investigate the effect of citric acid (CA) and fermentation time on the fermentation quality of Chamaecrista rotundifolia silage. Chamaecrista rotundifolia was used as the raw material and the treatments were the addition of 0 (CK), 0.1% (group Ⅰ), 0.3% (group Ⅱ), 0.5% (group Ⅲ), and 1.0% (group Ⅳ) CA to silage for 30, 45, and 60 days. After the silage process, samples were taken to measure and analyze the nutrient composition and fermentation quality of Chamaecrista rotundifolia silage. The results showed that 1) CA had little influence on the dry matter (DM) and water soluble carbohydrate (WSC) contents of Chamaecrista rotundifolia silage. 2) The crude protein (CP) and lactic acid (LA) contents of the experimental groups were significantly higher than those in CK (P < 0.05). The detergent fiber (NDF), acid detergent fiber (ADF), and propionic acid (PA) contents, pH, and the NH3-N/TN ratio of the experimental groups were significantly lower than those for CK (P < 0.05), and the effects of groups Ⅲ and Ⅳ were better than the other experimental groups. However, the acetic acid (AA) content in group Ⅲ was significantly lower than that in the other treatment groups (P < 0.05). 3) The interaction effect between the CA additive and fermentation time had significant effects on the NDF, ADF, NH3-N/TN, and PA contents (P < 0.05), but had no significant effects on other nutrient and fermentation indexes (P > 0.05). In conclusion, different CA levels and different fermentation times can improve the nutrient quality and fermentation characteristics of Chamaecrista rotundifolia silage and the best improvement effect was observed when the CA supplemental level was 0.5% (FM) for silage at 30 days.
The aim of the current study was to determine the best sowing mixture and sowing ratios of triticale (× Triticosecale Wittmack ‘Gannong No. 2’) with common vetch (Vicia sativa). The production performance and nutritional value of three vetch varieties (i.e., Lvjian 1, Lvjian 2, and Lvjian 431) and the triticale variety Gannong No. 2 were tested in different mixed sowing ratios (0 ꞉ 100, 20 ꞉ 80, 30 ꞉ 70, 40 ꞉ 60, 50 ꞉ 50, 60 ꞉ 40, 70 ꞉ 30, 80 ꞉ 20, and 100 ꞉ 0). A spilt-plot design was used in the experiment, where sowing mixtures were assigned to main plots, and sowing ratios were assigned to subplots. The results showed that the sowing mixture of Lvjian 431 and Gannong No. 2 triticale scored the highest performance for hay yield, nutritional value, and the comprehensive evaluation value (0.941 6); the sowing ratio of 50 ꞉ 50 had the best mixed broadcast effect among the mixed sowing ratios. The interaction showed that the mixed sowing treatment of Lvjian 431 and Gannong No. 2 triticale at a ratio of 50 ꞉ 50 scored the highest hay yield (11.15 t·ha−1), the highest comprehensive evaluation value (0.832 1), high crude protein (CP) content (13.25%), and the highest mixed broadcast effect. These results will assist the scientific establishment and management of grass–legume mixed grasslands in Gannan alpine pasture areas.
Grassland biomass is an important indicator of the productivity of grassland ecosystems and an important factor in evaluating the material cycle of grassland ecosystems. This study was designed to systematically evaluate the research progress of using remote sensing to monitor grassland biomass. To this end, we collected 557 documents related to the remote sensing-based evaluation of grassland biomass from the Web of Science produced between 1995 and 2020. This dataset was then evaluated using CiteSpace, which allowed for information visualization and analysis from the perspective of country/institution/discipline distribution, keyword co-occurrence, document co-citation and journal co-citation. The results show that the number of papers produced using remote sensing technologies has largely increased over the last few decades. The top three countries producing this type of research are the United States, China and Germany. The number of documents issued by the Chinese Academy of Sciences far exceeds that of any of the other institutions, and ecology, environmental science, and remote sensing are the primary disciplines described in these papers. “Ecology” is the most cited journal and has the greatest influence in this field. The keyword co-occurrence map shows that vegetation, grassland, climate change, ecology, and above-ground biomass are all important node keywords. Additional analysis of the hot keywords and the results of cited literature clustering show that new remote sensing data sources and model construction methods should bring new opportunities for the development of novel applications for remote sensing-based monitoring of grassland biomass.
In order to present the current trends in the research field on Elymus and the influence of different countries, institutions, researchers, and journals on this field, the VOSviewer and CiteSpace softwares were used to perform statistical analysis and investigate the relevant literature on Elymus in the CNKI and Web of Science between 1980–2020. The results showed that the quantity of Elymus-related articles was stabilized after a period of increase over 1980 to 2020. The results also showed that China made the greatest contribution to international cooperation and ranked the first in the number of articles, accounting for 56.6% of the WOS database, indicating that China had a high influence in the research field on Elymus. In the WOS database, the Lanzhou University ranked the first in terms of article numbers and total citations, while the United States Department of Agriculture rated at the top of the list in the highest average citation times. Among the Chinese research institutions, the Inner Mongolia Agricultural University, Lanzhou University, and Chinese Academy of Sciences ranked first to third, respectively, in the highest number of published articles, total citation times, and average citation times. The analysis of the research frontier trend and citation showed that the keywords in the research field on Elymus, such as ‘Species richness’, ‘Qinghai-Tibet Plateau’, and ‘Vegetation restoration’, were the research hotspots in recent years. Therefore, the wide application of Elymus in ecology restoration and related research fields will be key research directions on Elymus.
The growth performance indices of Hu sheep male lambs during the fattening period such as feed intake, body size, and body weight in 80～180 days were measured by single pen feeding for 20 days as a test cycle, with the aim of studying the effect of average daily gain (ADG) on growth performance, slaughter performance, and muscle quality of Hu sheep. Slaughter performance and muscle quality were measured immediately after the measurement of growth performance. According to the ADG from 80 to 180 days, the test group was divided into high (H), medium (M), and low (L) groups, with 76, 110, and 66 Hu sheep, respectively. The results showed that: 1) The increases in body height, body length, and chest circumference of Hu sheep in group H were significantly higher than those in group L (P < 0.05), and better than those in group M (P > 0.05). 2) The pre-slaughter live weight, carcass weight, and carcass length of Hu sheep in group H were significantly higher than those in group L (P < 0.05), and the proportion of head and hoof weight and organ weight (except liver weight) to pre-slaughter live weight of Hu sheep in group L was significantly higher than those in the other two groups (P < 0.05), and the proportion of liver weight and its proportion to pre-slaughter live weight in group H were significantly higher than those in groups L and M (P < 0.05); the GR value, backfat thickness, tail fat weight, perirenal fat weight, and mesenteric fat weight in group H were significantly higher than those in the other two groups (P < 0.05), and the proportion of mesenteric fat weight to pre-slaughter live weight was significantly higher than that in group L (P < 0.05). 3) There were no significant differences (P > 0.05) between the three groups of Hu sheep in terms of cooked meat percentage, water loss, drip loss, shear force, pH1, and 24 h meat color. Furthermore, 45 min a* (redness) and 45 min b* (yellowness) were significantly higher in group L than in the other two groups (P < 0.05), and pH24 and 45 min L* (brightness) were significantly lower in group H than in the other two groups (P < 0.05). The production performance of Hu sheep in group H was the best, with higher body weight and meat production absolute value, and there was no significant difference in muscle quality among the three groups. The relative weight of the liver had a significant effect on the growth rate of Hu sheep, which may be related to the metabolic capacity of the liver, but the exact mechanism needs to be confirmed by further studies.
The effects of different ratios of mixed hay on the rumen and intestinal microflora of male dairy goats were studied using high-quality forage grass planted between rows in Weibei orchard, thereby providing a theoretical basis for the ecological breeding cycle model of “orchard – grass – livestock” in Weibei dry highland. (Method) Twenty-four 2 month-old healthy male goats of similar weight were selected and randomly divided into four groups with three replicates in each group and two goats in each replicate. The local traditional feeding method was used for the control group (CK), which included crop stalks (corn stalks and wheat stalks), alfalfa, and a small amount of field weeds. The three treatment groups consisted of a mixture of two types of hay (1 ꞉ 1), alfalfa + oat mixed hay (group Ⅰ), alfalfa + perennial ryegrass (group Ⅱ), and vetch + perennial ryegrass (group Ⅲ). Sampling and determination were conducted after 85 d of feeding. The bacterial composition of the rumen and cecum was determined using the 16S rDNA technique. (Results) The results showed that 1) group Ⅱ significantly increased the alpha diversity of the lamb intestinal flora (P < 0.05) compared with that of CK. Groups Ⅰ and Ⅲ had higher alpha diversity of lamb rumen bacteria, but this difference was not significant (P > 0.05). 2) For intestinal bacteria, the three orchard mixed hay combinations (groups Ⅰ, Ⅱ, and Ⅲ) had a significant effect on the relative abundance of Firmicutes compared with CK (P < 0.05). The relative abundance of Bacteroides in group Ⅱ was significantly higher than that in the other three groups (P < 0.05), and the relative abundances of Romboutsia and Clostridium in groups Ⅰ, Ⅱ, and Ⅲ were significantly higher than those in CK (P < 0.05). For rumen bacterial flora, the relative abundance of Bacteroides in group Ⅲ was significantly higher than that in the other three groups (P < 0.05), the relative abundance of Proteobacteria in group Ⅱ was significantly higher than that in the other three groups (P < 0.05), the relative abundance of Prevotella in group Ⅲ was significantly higher than that in the other groups (P < 0.05), and the relative abundance of Rikenellaceae RC9 in groups Ⅱ and Ⅲ was significantly higher than that in CK (P < 0.05). (Conclusion) In summary, feeding mixed hay from different orchards can increase the diversity of the gastrointestinal bacterial community, increase the abundance of beneficial bacteria in the gastrointestinal tract, and reduce the abundance of pathogenic bacteria in lambs, thereby keeping the lambs healthy. Alfalfa + perennial ryegrass was the best hay mixture.
Habitat fitness is a broad concept of environmental factors including climate, food, and risk; it has a decisive influence on the natural distribution pattern and population dynamics of the plateau pika (Ochotona curzoniae). Based on the plateau pika’s habitat selection and preferences, and basic habitat characteristics, this paper investigated the relationship between habitat fitness of plateau pikas and snowfall by comparing the characteristics of pika populations among different vegetation patches. The results showed that the rate of snowmelt was positively correlated with the pika population density, the area of bare land, and the number of mounds, while it was negatively correlated with the height of vegetation. Whether food can be obtained shortly after snowfall was an important indicator for habitat fitness, and the basic driver of plateau pika behavioral orientation. Vegetation characteristics are an important factor affecting the rate of snowmelt, and vegetation patchiness is an important indicator for determining the distribution pattern of the plateau pika population and predicting its dynamic trend.
The traditional methods used for surveying underground rodent populations, such as the manual trapping and mound counting methods, are time consuming and labor intensive. Aerial photography by an unmanned aerial vehicle (UAV) is a flexible, easy-to-operate technology that can realize the dynamic analysis of ground data and aerial images. In this study, UAV-facilitated aerial photography, conducted at different flight altitudes and shooting areas, was used to investigate the density of ground mounds of Myospalax psilurus at 13 representative locations in the meadow grasslands of Hulunbuir. In combination with a manual ground survey of the mound numbers, the aerial images were visually interpreted to determine the number of mounds and to analyze the best aerial height of the drone. The relationship between the aerial photography area and the mound density was analyzed, and the minimum sampling area for the UAV investigation of the M. psilurus ground mounds was clarified. The results indicated that for investigating the relative population of M. psilurus in the meadow grasslands of Hulunbuir, the best aerial photography height of the drone is 50 m and the minimum sampling area is 2.21 ha.
Estimation of the ecosystem service value of grasslands is important for understanding the importance of this land type and maintaining ecological security in Gansu Province. In this study, the benchmark unit price of the ecosystem service value of grasslands in Gansu Province was calculated using data of the main grain crops in the province. Combined with the biomass data of each grassland type, the ecosystem service value equivalent of each grassland type in Gansu Province was both revised and calculated. The results showed that 1) the value of other ecosystem services provided by grasslands was much greater than the value of the providing services; 2) the ecosystem service value per unit area of warm shrub herbosa in Gansu Province was the highest (84 418.28 CNY·ha−1) and that of the temperate desert was the lowest (10 120.21 CNY·ha−1); 3) the grassland ecosystem service value was 7 069.73 × 108 CNY, which was 23 times more than the total output value of animal husbandry in Gansu Province and almost equal to the gross domestic product of the province in 2016; and 4) the alpine meadow had the highest ecosystem service value (1 733.27 × 108 CNY), and its contribution rate to the grassland ecosystem service value in Gansu Province was 24.52%. The ecosystem service value of the alpine desert was the lowest (58.51 × 108 CNY), and its contribution rate was 0.83%. The data from this study provide a basis for the scientific and reasonable estimation of ecosystem service values and the formulation of punitive measures against players contributing to ecosystem damage.
Grassland is the largest terrestrial ecosystem in China, and consequently, grassland security closely mirrors national ecological security. As an important area of grassland distribution in the country, the Loess Plateau is one of the most seriously affected areas in the world in terms of soil erosion. Accordingly, with respect to the restoration and reconstruction of vegetation and ecological protection, it is of considerable significance to examine the evolution of grassland vegetation on the Loess Plateau. In this study, we systematically studied the transmutation of grassland vegetation on the Loess Plateau based on a literature review and examination of the historical data. The results indicate that grassland has been the main vegetation type on the Loess Plateau during geological history. From the Pleistocene to the mid-Holocene, grassland vegetation on the plateau underwent numerous changes in the characteristics of forest-grassland, grassland, and desert grassland in response to climate change. Coinciding with an end to the warm period during the late Holocene, there was an overall cooling and drying of the climate, an increase in the human population base, and the development of agricultural civilization. Furthermore, forest steppe on the Loess Plateau changed to dry steppe and the steppe belt migrated southward, whereas the grassland vegetation became severely damaged and reduced in area, and the distribution of desert grassland expanded. Since modern times, with the gradual development of soil and water conservation work on the Loess Plateau, ecological restoration initiatives have gradually been highlighted from the 1980s. Under the implementation of ecological projects such as the construction of the three-north shelterbelt system, the return of farmland to forest and grassland, the restoration and reconstruction of natural grassland vegetation, and a pilot project for the protection and restoration of the mountains, rivers, forests, farmlands, lakes, and grassland systems, there has been an effective control of environmental problems, such as grassland degradation and soil erosion, on the Loess Plateau. Currently, vegetation coverage on the Loess Plateau grasslands and mountains has been markedly promoted, and the degree of vegetation restoration has satisfied the requirements of the regional water resource capacity. Despite these achievements, however, this essentially represents a new phase of development in the ecological reconstruction of Loess Plateau grassland, and one that needs to be continually monitored.