No abstract

Grassland ecosystems on the Qinghai–Tibet Plateau (QTP) provide numerous ecosystem services and functions to both local communities and the populations living downstream through the provision of water, habitat, food, herbal medicines, and shelter. This review examined the current ecological status, degradation causes, and impacts of the various grassland degradation mitigation measures employed and their effects on grassland health and growth in the QTP. Our findings revealed that QTP grasslands are continually being degraded as a result of complex biotic and abiotic drivers and processes. The biotic and abiotic actions have resulted in soil erosion, plant biomass loss, soil organic carbon loss, a reduction in grazing and carrying capacity, the emergence of pioneer plant species, loss of soil nutrients, and an increase in soil pH. A combination of factors such as overgrazing, land-use changes, invasive species encroachment, mining activities, rodent burrowing activities, road and dam constructions, tourism, migration, urbanization, and climate change have caused the degradation of grasslands on the QTP. A conceptual framework on the way forward in tackling grassland degradation on the QTP is presented together with other appropriate measures needed to amicably combat grassland degradation on the QTP. It is recommended that a comprehensive and detailed survey be carried out across the QTP to determine the percentage of degraded grasslands and hence, support a sound policy intervention.

Water plays an important role in power generation, fuel manufacturing, and processing. This has been valid for several decades, but lately, primarily due to climate change, the limitations and insecurity related to water energy connections have become more prominent. The article is a quantitative review study conducted to evaluate the water–energy nexus in the Middle East and North Africa (MENA) region. Information about the review was generated from online databases by using keywords such as water–energy nexus, MENA region, Power Generation, Fuel Manufacturing, Energy-intensive, Energy Management Decisions, and Desalination Systems. Drip irrigation in Morocco played a vital role in the water–energy nexus for resource conservation and their better utilization. From the findings, it was revealed that distorted coupling with a relatively low reliance on freshwater energy systems has a high reliance on conceptual water and energy production systems. For Saudi Arabia, extraction and desalination of groundwater are projected to be up to 9% of total annual electricity use. Policymakers should consider energy implications for water-intensive food imports and possible water demand restructuring. This would lead to more coordinated water and energy management decisions. A comprehensive evaluation in some cases promotes the reuse of water and improvements in the agricultural sector rather than the development of energy-intensive and expensive desalination systems. One of the limitations for water–energy nexus in the MENA region is its unintelligible patterns for policy and decision-makers, and this quantitative review can be a major advancement in this regard. This study also highlights the use of water as an energy production source as well as the energy that is being utilized in water treatment and processing and their interrelationship. Cohesive and strategic tactics can lead technology’s research and development to reporting local issues of water and energy issues. Improving and participating models and data will better assist scholars, decision-makers, and the community. This water–energy nexus study mounts relevant challenges and areas of improvement for future research.

Grazing is a substantial threat to the sustainability of grassland ecosystems, while it is uncertain about the variety of plant and soil microbial community and the linkages between them limit the comprehensive understanding of grazing ecology. We conducted an experiment on the effects of the grazing regimes rotational grazing (RG), continuous grazing (CG), and grazing exclusion (GE) on an alpine meadow in Qinghai-Tibetan Plateau. The differences of plant community composition, soil microbial community assembly mechanism, and taxonomic and functional composition between grazing regimes were examined, and the relationship between plant species and the soil microbes was assessed by constructing a co-occurrence network. The results showed that the plant community composition varied with the grazing regimes, while the soil microbial community composition did not vary with the grazing regimes. The soil bacterial functional composition was similar under RG and CG, while the soil fungal functional composition was similar under GE and RG. The soil microbial community under all grazing regimes was assembled mainly according to stochastic rather than deterministic mechanisms, and RG and CG reduced the relative importance of the stochastic ratio. At the microbial phylum level, CG and GE increased the relative abundance of Acidobacteria and Armatimonadetes and CG and RG increased the relative abundance of Elusimicrobia. In the network of plant species and soil microbial classes, plants and bacteria themselves were mainly positively linked (symbiosis and promotion), while plants and soil microbes were mainly negatively linked (competition). There were five microbial generalists in the network, which connected with many microbes, and four showed no difference in their abundance among the grazing regimes. Overall, the stable key microbes in the network and the fact that many of the plants are unconnected with microbes weakened the impact of grazing-induced changes in the plant community on soil microbes, probably resulting in the stable soil microbial community composition. Moreover, there was still a dominant and tolerant plant species, Kobresia pygmaea, that connected the plant and microbial communities, implying that the dominant plant species not only played a crucial role in the plant community but also acted as a bridge between the plants and soil microbes; thus, its tolerance and dominance might stabilize the soil microbial community.