Aims
Viable seeds in herbivore dung constitute the dung seed bank, and the contribution of livestock dung to this seed bank in grazing pastures is often overlooked. Grazing season (warm and cold), ...seed characteristics (size and shape), and forage preference are the main factors that affect the size and composition of the dung seed bank and ultimately affect grassland ecology. However, how these three factors interact is unclear.
Methods
We collected yak dung as well as seeds of the common plant species from warm- and cold-season alpine meadows in northeastern Qinghai-Tibetan Plateau, and explored how grazing season (warm and cold), seed characteristics (size and shape) and foraging preferences (temporary cages method) affects yak dung seedling density, richness and diversity in an alpine pasture.
Results
Forty-three plant species (mainly perennials) germinated from yak dung. Dung seedling density, richness, and diversity did not differ significantly between the two grazing seasons. Small to medium-sized spherical seeds (seed size < 10 mg, shape index < 0.5) had the greatest germination potential.
Conclusions
Yaks vary their forage preference depending on the season (phenological period), and endozoochory occurs throughout both grazing seasons. Seed shape and size directly regulate the dung seedling density, richness, and diversity. Dung seedlings increase the heterogeneity of the aboveground vegetation near the microsites of the dung pieces and therefore promote grassland patching. Our study demonstrates that grazing season, seed characteristics, and yak forage preferences affect the dung seed bank in grazing ecosystems.
Rumen microbiota in ruminants are vital for sustaining good rumen ecology, health, and productivity. Currently, limited information is available regarding the response of yaks (Bos grunniens) to ...fluctuating environments, especially the rumen microbiome. To address this, we investigated the diet, rumen bacterial community, and volatile fatty acids (VFA) of rumen fluid of yaks raised in the great Qinghai-Tibet plateau (QTP) at 2800 (low altitude, L), 3700 (middle altitude, M), and 4700 m (high altitude, H) above sea level.
The results showed that despite a partial diet overlap, H yaks harbored higher fibrous fractious contents than the M and L grazing yaks. Bacteria including Christensenellaceae_R-7_group, Ruminococcus_1, Romboutsia, Alloprevotella, Eubacterium coprostanoligenes, Clostridium, Streptococcus, and Treponema were found to be enriched in the rumen of yaks grazing at H. They also showed higher rumen microbial diversity and total VFA concentrations than those shown by yaks at M and L. Principal coordinates analysis (PCoA) on weighted UniFrac distances revealed that the bacterial community structure of rumen differed between the three altitudes. Moreover, Tax4fun metagenome estimation revealed that microbial genes associated with energy requirement and carbohydrate metabolic fate were overexpressed in the rumen microbiota of H yaks.
Collectively, our results revealed that H yaks had a stronger herbage fermenting ability via rumen microbial fermentation. Their enhanced ability of utilizing herbage may be partly owing to a microbiota adaptation for more energy requirements in the harsh H environment, such as lower temperature and the risk of hypoxia.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Aims
Deposition of urine and dung is a key mechanism by which herbivores influence the nutrient cycling of terrestrial ecosystems. Yet, little is known about the roles of urine, dung and their ...mixtures in regulating the plant and soil carbon:nitrogen:phosphorus (C:N:P) stoichiometry and their interactions.
Methods
We explored how different excrement types (urine, dung and their mixtures) and supply levels urine: 0.5, 1.0 and 1.5 L m
−2
; dung: 4.7, 9.4 and 14.2 g m
−2
; mixtures (urine+dung): 0.5 + 4.7, 1.0 + 9.4 and 1.5 + 14.2 altered the plant and soil C:N:P stoichiometry in a semi-arid grassland on the Loess Plateau.
Results
We found that the aboveground biomass of the whole community was highest at the highest mixtures application rate, while the highest aboveground biomass of the three dominant species was detected at applications of 0.5 L m
−2
urine for
Stipa bungeana
, 9.4 g m
−2
dung for
Lespedeza davurica
and 1.0 L m
−2
urine +9.4 g m
−2
dung for
Artemisia capillaris
. Urine and dung alone increased plant N concentration, which peaked at 1.0 L m
−2
urine. Plant P concentration at 1.5 + 14.2 mixtures was significantly higher than that at control without significant difference between excrement types. Compared to the control, excrement deposition did not significantly change plant C concentration and C:N, C:P and N:P ratios. However, plant C:P and N:P ratios under the mixtures were significantly lower than those under urine or dung. Excrement applications led to more soil (total, microbial and organic) C, N and P accumulations. Compared to urine and dung, the mixtures induced higher total P concentration but lower total N concentration in soil.
Conclusions
Our study demonstrated that the impacts of sheep urine and dung on plant and soil C and nutrient concentrations and stoichiometry differed from that of mixtures. The plant N:P ratio indicated balanced N:P supply for urine and dung applications but N limitation for mixtures application. This study provides experimental evidence that the excrement of herbivores plays an important role in altering ecological stoichiometry in plants and soil.
The Loess Plateau of China is one of the most fragile ecosystems worldwide; thus, human production activities need to be conducted very cautiously. In this study, MiSeq high-throughput sequencing was ...applied to assess the relationship between bacterial and fungal community structures and changes in vegetation and soil physical and chemical properties induced by grazing, in four grasslands with different levels of grazing intensity (0, 2.67, 5.33, and 8.67 sheep/ha) in the semiarid region of the Loess Plateau. The relative abundances of the bacterial community in the grasslands with 2.67 and 5.33 sheep/ha were significantly higher than those in grasslands with 0 and 8.67 sheep/ha, and the fungal diversity was significantly lower for grasslands with 2.67 sheep/ha than for the other grasslands. Redundancy analysis (RDA) showed that plant biomass, nitrate, and total nitrogen have significant effects on bacterial community structure, whereas nitrate and total nitrogen also significantly affect fungal community structure. Variation partitioning showed that soil and plant characteristics influence the bacterial and fungal community structures; these characteristics explained 51.9 and 52.9% of the variation, respectively. Thus, bacterial and fungal community structures are very sensitive to grazing activity and change to different extents with different grazing intensities. Based on our findings, a grazing intensity of about 2.67 sheep/ha is considered the most appropriate in semiarid grassland of the Loess Plateau.
Ruminants are completely dependent on their microbiota for rumen fermentation, feed digestion, and consequently, their metabolism for productivity. This study aimed to evaluate the rumen bacteria of ...lactating yaks with different milk protein yields, using high-throughput sequencing technology, in order to understand the influence of these bacteria on milk production.
Yaks with similar high milk protein yield (high milk yield and high milk protein content, HH; n = 12) and low milk protein yield (low milk yield and low milk protein content, LL; n = 12) were randomly selected from 57 mid-lactation yaks. Ruminal contents were collected using an oral stomach tube from the 24 yaks selected. High-throughput sequencing of bacterial 16S rRNA gene was used.
Ruminal ammonia N, total volatile fatty acids, acetate, propionate, and isobutyrate concentrations were found to be higher in HH than LL yaks. Community richness (Chao 1 index) and diversity indices (Shannon index) of rumen microbiota were higher in LL than HH yaks. Relative abundances of the Bacteroidetes and Tenericutes phyla in the rumen fluid were significantly increased in HH than LL yaks, but significantly decreased for Firmicutes. Relative abundances of the Succiniclasticum, Butyrivibrio 2, Prevotella 1, and Prevotellaceae UCG-001 genera in the rumen fluid of HH yaks was significantly increased, but significantly decreased for Christensenellaceae R-7 group and Coprococcus 1. Principal coordinates analysis on unweighted UniFrac distances revealed that the bacterial community structure of rumen differed between yaks with high and low milk protein yields. Furthermore, rumen microbiota were functionally enriched in relation to transporters, ABC transporters, ribosome, and urine metabolism, and also significantly altered in HH and LL yaks.
We observed significant differences in the composition, diversity, fermentation product concentrations, and function of ruminal microorganisms between yaks with high and low milk protein yields, suggesting the potential influence of rumen microbiota on milk protein yield in yaks. A deeper understanding of this process may allow future modulation of the rumen microbiome for improved agricultural yield through bacterial community design.
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•We studied effect of slope direction and gradient on biocrust and soil physiology.•SEM used to investigate effects of biocrusts on vegetation-soil coupling conditions.•Middle slope ...has least severe soil erosion for continuous slope change.•Biocrust mediates changes in vegetation-soil coupling.
Biocrust is widely distributed on land surfaces worldwide, it is especially important in arid and semi-arid areas with serious soil erosion; however, the impact of biocrust on vegetation soil coupling in complex topography has not been reported. This study revealed the variation of biocrust coverage in different slope direction and gradient, and the fluctuation of vegetation and subsoil physicochemical properties mediated by it. The SEM (Structural equation modeling) further investigated the effects and pathways of biocrusts on soil-vegetation coupling conditions. The results indicated that the degree of coupling of the sunny slope showed a trend of gradual dispersion with a starting point of 1 as the slope decreased, whereas the coupling degree of the shady slope showed an overall process of gradual aggregation towards 1. In addition, the SEM showed that the moss on sunny slopes affected degree by nourishing vegetation (47%) and the effect of soil on coupling degree is more obvious (23%) on shady slopes. As for lichen system, it affected the coupling degree (27%) by itself on sunny slopes, and it further influencing coupling on shady slopes through the mediation of vegetation (54%). Our research results provide a theoretical of the coupling of soil and vegetation in middle slope (45°) is best in two directions, and provide a reference for the segmented management of soil erosion under continuous slope changes.
Grasslands occupy 40% of the world’s land surface (excluding Antarctica and Greenland) and support diverse groups, from traditional extensive nomadic to intense livestock-production systems. ...Population pressures mean that many of these grasslands are in a degraded state, particularly in less-productive areas of developing countries, affecting not only productivity but also vital environmental services such as hydrology, biodiversity, and carbon cycles; livestock condition is often poor and household incomes are at or below poverty levels. The challenge is to optimize management practices that result in “win-win” outcomes for grasslands, the environment, and households. A case study is discussed from northwestern China, where it has been possible to reduce animal numbers considerably by using an energy-balance/market-based approach while improving household incomes, providing conditions within which grassland recovery is possible. This bottom-up approach was supported by informing and working with the six layers of government in China to build appropriate policies. Further policy implications are considered. Additional gains in grassland rehabilitation could be fostered through targeted environmental payment schemes. Other aspects of the livestock production system that can be modified are discussed. This work built a strategy that has implications for many other grassland areas around the world where common problems apply.
The dominance of Ligularia virgaurea and Ligularia sagitta related to significant changes in plant community and soil microenvironment. Red and blue lines represent positive and negative influences, ...respectively. Purple lines indicate the largest relative influence.
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•Plant community productivity and species richness were reduced by Ligularia spp.•Ligularia spp. reduced the organic mater and nitrogen content of soil.•Proteobacteria and Bacteroidetes abundance in soil increased under Ligularia spp.•Actinobacteria and Verrucomicrobia abundance in soil declined under Ligularia spp.
Exploring how plants adapt to and change the surrounding environment has become essential to understanding their survival strategies and co-evolution mechanisms. Ligularia virgaurea and Ligularia sagitta are the two most common species in the alpine grazing ecosystems of the eastern Qinghai-Tibetan Plateau (QTP) and becoming increasingly dominant. Studies have suggested that overgrazing has allowed Ligularia to gain a competitive advantage by changing plant community structure, which is often closely related to the soil environment. However, we don’t fully understand the soil environment changes during this process, and the underlying mechanisms have not been explored. Therefore, we investigated plant community characteristics, soil fertility and soil microbial diversity in the L. virgaurea and L. sagitta communities on the eastern QTP. Ligularia spp. significantly changed the plant community by reducing biomass, vegetation coverage, abundance, and biodiversity, and the effect of L. sagitta on the plant community was stronger than that of L. virgaurea. In the plant communities dominated by L. virgaurea and L. sagitta, soil nutrients and soil microbial communities changed significantly. Aggregated boosted trees analysis revealed that soil Mg levels had the greatest relative influence on the structure and diversity of the soil microbial community. Our study provides data and a theoretical basis for revealing the survival strategies of L. sagitta and L. virgaurea and, provides a basis for weed management in grazed ecosystems.
•We verified if salty, sweet, and bitter taste agents affect yak grazing behaviour.•Application of sweet and salty agents increased grazing intake.•Application of bitter agent had an inhibitory ...effect on grazing intake.•Taste agents may influence grazing behaviour by regulating feeding behaviour.•The results provide a method to promote grassland community stability.
Feeding behaviour plays a significant role in promoting good animal health and welfare. It is also reflective of the quality and quantity of available feed. In fact, grazing livestock do not select their feed randomly, rather their behaviour is influenced by the texture, taste, and smell of each pasture species. Although taste agents are often used to modify feed intake for captive livestock, the effect on the feeding behaviour of grazing livestock has not yet been extensively evaluated in native grasslands. To address this gap in knowledge, herein, we sprayed three types of taste agents—salty (SA), sweet (SW), and bitter (BT)—on alpine meadows to investigate their effect on the grazing behaviour of yaks (Bos Grunniens) on the Qinghai-Tibetan Plateau (QTP). Behavioural observations showed that grazing was concentrated primarily in the morning and afternoon, while ruminating/resting peaked at noon; however, the diurnal behavioural patterns of grazing yaks were not affected by the taste agents. Application of the SA agent significantly increased the yaks’ grazing time, bites per minute, bites per step, time per feeding station, and steps per feeding station, while significantly reducing walking time, steps per minute, and number of feeding stations per minute. Meanwhile, application of the SW agent significantly increased the yaks’ time per feeding station, however, significantly reduced the steps per minute and number of feeding stations per minute. In contrast, the BT agent significantly increased the yaks’ walking time, steps per minute, and number of feeding stations per minute, while significantly reducing grazing time, bites per minute, bites per step, and time per feeding station. Application of the SA agent also significantly increased the intake of favoured, edible, and inedible forage, while the SW agent improved inedible forage intake, however, had a more subtle effect on favoured and edible forage intake. Meanwhile, the BT agent had an inhibitory effect on grazing intake. Hence, the structural equation model suggested that taste agents may directly or indirectly influence grazing behaviour by regulating feeding behaviour. Our findings provide a theoretical basis for using taste agents in grasslands to control the grazing behaviour of livestock and provide a method to promote the stability of grassland communities, while mitigating the degradation of grasslands in the QTP.
Caffeic acid (CA) is one of the major phenolic acids of coffee with multiple biological activities. Our previous study found that 500 mg/kg of chlorogenic acid (CGA) had the potential capacity of ...alleviating colonic inflammation. Moreover, CGA can be degraded into caffeic acid (CA) by the gut microbiota in the colon. Therefore, we hypothesize that CA can exert protective effects on colonic inflammation. To test the hypothesis, 251 mg/kg CA was supplemented to DSS-induced colitis mice. The results showed that CA treatment recovered DSS-induced disease activity index (DAI), colon length, and histopathology scores of colon tissue. Additionally, CA treatment significantly decreased pro-inflammatory cytokines and malondialdehyde (MDA) levels and increased the level of IL-10, total antioxidant capacity (T-AOC), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) in serum. qPCR results indicated that CA treatment dramatically downregulated mRNA expression of
IL-1β
,
IL-6
, and
TNF-α
as well as upregulated
SOD1
,
GPX1
,
GPX2
,
CAT
, and
IL-10
. In addition, CA supplementation significantly increased mRNA expression of
Nrf-2
,
HO-1
, and
NQO1
, which showed its antioxidant and anti-inflammatory capacities potentially by activating the Nrf-2/HO-1 pathway. Moreover, CA supplementation prevented gut barrier damage by enhancing
Occludin
gene expression. Furthermore, CA supplementation altered the gut microbiome composition by decreasing the relative abundance of
Bacteroides
and
Turicibacter
, and enhancing the relative abundance of
Alistipes
and
Dubosiella
. Meanwhile, CA supplementation increases the abundance of
Dubosiella
and
Akkermansia
. In conclusion, CA supplementation could effectively alleviate DSS-induced colitis by improving the defense against oxidative stress and inflammatory response.
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