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Plant–microbial interaction for nitrogen (N) is important in plant growth, soil fertility, and function of grasslands. However, it remains unclear how plant–microbial competition for N changes after the restoration of degraded alpine grasslands. This study aimed to explore the dynamics of plant–microbial competition for N in restoration chronosequences (i.e., short-, medium-, and long-term) in an alpine meadow and an alpine steppe on the Qinghai–Tibetan Plateau. Two inorganic forms of N (ammonium (NH4+) and nitrate (NO3−)) and one organic N (glycine) were used for the in situ 15N labeling experiments. The competition between microorganisms and plants (i.e., ratios) for N increased by 4.8 times after medium- than short-term restoration in the alpine meadow and remained stable after each restoration. Compared to short-term restoration, medium-term restoration increased the N uptake of microorganisms by 2.4 times in alpine meadow and 4.3 times in alpine steppe. Microorganisms and plants showed chemical niche differentiation between NH4+ and NO3− uptake in both alpine ecosystems after medium-term restoration, with microorganisms taking up more NH4+ but plants taking up more NO3−. Competition between microorganisms and plants decreased after long-term compared with medium-term restoration, maintaining the microbial to plant N uptake ratio > 1. Long-term restoration increased plant N uptake in the alpine meadow, while decreased the microbial N uptake in the alpine steppe. Neither microorganisms nor plants showed a preference for glycine, but glycine uptake by microorganisms was higher than plants after medium- and long-term restorations. These findings provide valuable insights into the restoration of degraded alpine grasslands from the perspective of plant–microbial competition for available N in soil, which may be useful for developing sustainable grassland management practices. [ABSTRACT FROM AUTHOR]

Strengthening the construction of rural resilience and improving the rural ecotope and biodiversity are of great significance to improving the governance’s abilities of rural areas to resist external disturbances and various crises. Based on the 1786 documents which are associated with the research topics collected in the “Web of Science” database from 1992 to 2022, this study uses the visualization analysis method of the “CiteSpace document” to focus on the rural resilience from the ecosystem perspective, sort out the hotspots of rural resilience construction research, and study and judge the future development tendencies. It pertinently put forward the research evolution trends of “bottom–up ecological restoration” and “top–down planning improvement.” The research results are beneficial to provide useful references and direction enlightenment for the sustainable research of rural resilience and the formulation of planning strategies from the perspectives of biodiversity.

Under the background of promoting the construction of ecological civilization and the goal of carbon peak and carbon neutralization, it is of great significance to explore the measurement method and improvement strategy of the carbon effect of agricultural land consolidation. Based on a quantitative analysis and the whole life cycle of land consolidation, this study constructed a carbon effect accounting and analysis framework of agricultural land consolidation project from three stages of project initiation and design, project implementation, and operation management. Taking the agricultural land consolidation project in the Shiyan town on the urban edge of the Three Gorges Reservoir Area as a case, this study made empirical analysis and calculation and analyzed the carbon effect and influencing factors in different consolidation stages. The results showed that the overall carbon effect in the project area was a carbon source. The net carbon emission generated by the project construction was 8358t, which was mainly from workers input and concrete carbon emission; the carbon storage brought about by the adjustment of land use structure was 2,378.20t, which mainly came from the carbon storage increment of newly cultivated land; the carbon storage generated by the agricultural ecosystem was 1,100.04t, which was mainly based on the increase of cultivated land and the improvement of cultivated land quality; the carbon emission from agricultural production activities was 18.18t. Research conclusions: ① the carbon source effect of engineering construction is obvious. Artificial input and concrete are the main carbon sources in the hilly area at the edge of the metropolis; ② the adjustment of land use structure is manifested as a carbon sink effect, which mainly comes from the contribution of carbon storage of newly increased cultivated land; ③ the carbon effect of project operation and management may be a carbon source in the short term, and the long-term effect should be exerted; and ④ based on the concept of whole life cycle, promoting ecological land consolidation, optimizing project design, reasonably arranging consolidation projects, and strengthening operation management are effective measures to improve the carbon effect of land consolidation projects, which are conducive to the realization of the “double carbon” goal.

Understanding the connections between biological communities and elemental cycles is increasingly important given that alterations to both are occurring on a global scale. Biological control of elemental cycles is tied to patterns of biomass and the elemental stoichiometry of organisms and organic matter (OM) pools that comprise ecosystems. The structure and size of these ecosystem components are, in turn, shaped by key environmental factors that influence species composition, functional traits, and OM and element storage. In stream and river ecosystems, temperature and flow regime have a strong influence on ecosystem structure and function, yet little is known about their relative importance in driving patterns of ecosystem OM and stoichiometry. We quantified ecosystem OM pools and elemental stoichiometry in 11 Icelandic streams across a wide gradient of temperature (~ 5 to 25 °C) and flow. Across these environmental gradients, we observed two orders of magnitude variation in ecosystem OM mass, as well as relatively large variation in certain ecosystem stoichiometries (that is, C:N, C:P). We found that flow regime was more important than temperature in driving variation in OM pools and stoichiometry because of large shifts in community structure, that is, from dominance by large-bodied macrophyte and bryophyte communities to epilithic and detrital OM pools. Although temperature is known to influence mass-specific rates of metabolic and chemical processes, our study suggests that the flow disturbance regime may be the dominant control on patterns of OM storage and may thus control ecosystem fluxes by constraining ecosystem OM pool mass, organism size structure, and stoichiometric traits. [ABSTRACT FROM AUTHOR]