Ecosystem Productivity Research Articles

Temporal dynamics of stream algae under the combined impacts of climate and land‐use stressors

Abstract Ecosystems are increasingly challenged by the multiple facets of climate change, coupled with intensifying land‐use pressures. These co‐occurring stressors can interact in complex ways, but we lack an empirical understanding of the impact of higher‐order interactions on temporal patterns. Using 128 flow‐through circular stream mesocosms, we investigated the individual and combined effects of two climatic stressors (CO2 enrichment, flow variability) and two land‐use‐related stressors (siltation, light—as lack of shading) on algal communities and net ecosystem productivity (NPP) in a full‐factorial design. The sediment pulses coincided with high flow to mimic erosion events, whereas CO2 and light disturbances were applied continuously, as they would in nature. Sediment emerged as a key stressor for algal biomass. Land‐use stressors had more pervasive individual effects, whereas climate‐change‐related stressors were more important in up to three‐way interactions with other stressors. However, CO2 was a key driver of NPP, followed by sediment and light, whereas flow variability was only important in interactions with other stressors. The effects of sediment and flow on algal biomass depended strongly on their temporal patterns. The combined effect of an increasing number of stressors on algal biomass appeared to reach saturation with three active stressors, with no apparent additional effect caused by the fourth stressor. Synthesis. Sediment emerged as a key stressor in streams. Despite the mounting evidence and the multitude of available mitigation strategies, this problem persists worldwide. The complex interactions uncovered in our study illustrate context‐dependency that can be masked in two‐factor experiments. Our findings also highlighted that temporal patterns of individual and co‐occurring stressors can determine the ecological outcome.

Monitoring seagrass meadows in Maputo Bay using integrated remote sensing techniques and machine learning

Seagrass meadows are one of the most productive and valuable ecosystems on the planet. Monitoring seagrass meadows is essential to understand how these habitats change, and to develop better management and conservation practices. This study integrated satellite imagery from Sentinel-2 and Unmanned Aerial Vehicles (UAV) using machine learning to provide a consistent classification approach for monitoring seagrass in Maputo Bay, southern Mozambique. Sentinel-2 imagery was used to map seagrass extent and changes in Maputo Bay. The UAV systems were used to map seagrass at species level and biomass. All three algorithms tested in the ArcGIS environment could detect seagrass with high producer accuracy and Kappa coefficient. The area of seagrass in Maputo Bay decreased by 33.4 % between 1991 and 2023, with a decreasing trend of 0.48 km2/yr. A zonation pattern was observed for Oceana serrulata and Zostera capensis from the UAV imagery. The small and narrow leaved species (Z. capensis) occurred in the intertidal zone replaced by the broadleaved species (O. serrulata) in the subtidal. The total average aboveground biomass was 33.2 kg dry weight for the mapped area. The results of this study will guide implementation of combined satellite and UAV imagery with machine learning techniques for seagrass monitoring and restoration in Mozambique.

Flow-weighted sourcing of freshwater runoff from Pacific-draining continental and coastal basins in south-western Patagonia (41-56° S): characterizing regional inputs to Chilean fjords

Global estimates of the supply of dissolved and suspended materials to the ocean, in order to be relevant at either political or ecological scales, belie a finer-scale analysis necessary for understanding specific terrestrial-marine interactions. This is especially true for continental runoff to the marine critical zone of inland fjords and channels, where mechanisms, drivers, and predictions need to be elaborated in the context of changing land use and shifting climate forcing. In fjords in south-western Patagonia, runoff from small coastal and large continental basins (~310 x103 km2), sourced from a diverse geography and wide climatic gradient (<150 – 6,000+ mm/year), correspond with a very low density of hydrological and water quality observations. Based on the recently developed regional runoff model (FLOW), we estimated the coastal freshwater discharges and characterized flow-weighted sourcing (land use-cover type, climate, glaciers/geology, and soil province) for Pacific drainages from 41° to 56° south latitude. An estimated 692 km3/year (mean across 1979-2018), or 2% of worldwide total, is more than 85% of previous estimates for the much larger Pacific South American input. Based on limited water quality observations and inference from runoff sourcing, we predict general patterns of export for four groups of continental resources important for marine productivity, including: significant regional variation in flow seasonality, a N-S gradient in declining input of silicic acid and increased glacial input of sediment and iron, and potential shift in dissolved organic matter input sources from rainforest (potentially labile) to peatlands (refractory). Finally, we emphasize the temporal and spatial consequences of near-reference condition river runoff for marine ecosystem productivity and function in the Patagonian fjords, with specific recommendations for water quality standards and sustained monitoring for coupled river and marine ecosystems.

Growth rate as a link between microbial diversity and soil biogeochemistry.

Measuring the growth rate of a microorganism is a simple yet profound way to quantify its effect on the world. The absolute growth rate of a microbial population reflects rates of resource assimilation, biomass production and element transformation-some of the many ways in which organisms affect Earth's ecosystems and climate. Microbial fitness in the environment depends on the ability to reproduce quickly when conditions are favourable and adopt a survival physiology when conditions worsen, which cells coordinate by adjusting their relative growth rate. At the population level, relative growth rate is a sensitive metric of fitness, linking survival and reproduction to the ecology and evolution of populations. Techniques combining omics and stable isotope probing enable sensitive measurements of the growth rates of microbial assemblages and individual taxa in soil. Microbial ecologists can explore how the growth rates of taxa with known traits and evolutionary histories respond to changes in resource availability, environmental conditions and interactions with other organisms. We anticipate that quantitative and scalable data on the growth rates of soil microorganisms, coupled with measurements of biogeochemical fluxes, will allow scientists to test and refine ecological theory and advance process-based models of carbon flux, nutrient uptake and ecosystem productivity. Measurements of in situ microbial growth rates provide insights into the ecology of populations and can be used to quantitatively link microbial diversity to soil biogeochemistry.

Net Primary Production of Steppe Ecosystems and the Reasons for its Spatial Variability

The purpose of the article is to analyze the values change of net primary production: aboveground (ANP), belowground (BNP) and total (NPP) for meadow, true and dry steppes. The investigated meadow and true steppes are located between 36 and 116° E, 47 and 56° N. In Tyva, the production of dry steppes is determined on various elements of the relief – from the upper part of the mountain to the depressions located in the bottom of the slope. The value of ANP in the meadow steppes varies from west to east from 10.2 to 3.1, in the true steppes from 5.8 to 0.7 t/ha per year and depends on many factors, including air temperature, precipitation, and soil properties. The soil properties are defined by a set of conditions: the position of the ecosystem on the relief, which leads to different soil moisture. Both, the meadow and true steppes, have irregularities in the decrease of the ANP value from west to east. In some cases, in a series of meadow steppes instead of a decrease, an increase of ANP is observed, which is explaining by changes in soil conditions. The first increase from 4.8 (63° E) to 6.1 t/ha per year (73° E) occurs when Luvic Chernozem (Loamic) is replaced by Inclinigleyic Chernozem (Loamic), as a result of additional soil moistening. The second increase of ANP from 3.6 (75° E) to 6.6 t/ha per year (90° E) is observed when the soil changes from Tonguic Chernozem (Siltic) to Haplic Chernozem (Siltic, Pachic). The increases of ANP were observed in the true steppes: 1) when Skeletic Kastanozem (Siltic) changed to Calcic Chernozem (Siltic), 2) when Haplic Solonetz (Loamic) changed to Calcic Chernozem (Loamic), 3) when soil changes from Mollic Leptosol (Siltic) to Calcic Chernozem (Siltic). The value of BNP in meadow and true steppes in the soil layer of 0–30 cm generally decreases from west to east from 26.8 to 7.7 t/ha per year, varying without a visible pattern. In Tyva, due to the change in the relief, ANP of dry steppes varies from 3.7 to 1.7, BNP – from 27.0 to 8.7 t/ha per year. Consequently, the amount of aboveground production of grass ecosystems is determined not only by air temperature and precipitation, but also by the properties of soils, which vary in structure, Corg content, nutrients, and watering.

Characterization and mechanism of phthalic acid esters bioaccumulation in dominant mangrove fish at different habitats in the mangrove ecosystem of Dongzhai Harbor, China

With the wide application of phthalic acid esters (PAEs) in the manufacturing of plastic products, a large number of PAEs were discharged into marine ecosystem and accumulated in fish, which has posed a serious threat to marine ecological environment and fishery resources. However, the bioaccumulation of PAEs in fish in mangrove ecosystem, the most productive marine ecosystem, has not been well characterized. In this study, dominant fish and their potential food sources (including particulate organic matter (POM), sedimentary organic matter (SOM), Metapenaeus ensis (Shrimp) and Oreochromis (Ore) were collected from Dongzhai Harbor, a typical mangrove ecosystem. The concentrations of nine PAEs in fish and their potential food sources were determined. Then stable nitrogen and carbon isotope analysis, combined with a new Bayesian mixing model (MixSIMMR) was used to quantify the diet compositions of fish and elucidate the effect of dietary habit on PAEs bioaccumulation in fish. The results indicated that the median concentration of ∑9PAEs in fish was 1119 μg/kg ww, positioning it at a moderate to low level in comparison to other regions. di-n-butyl phthalate (DBP) and diisononyl ortho-phthalate (DINP) were the dominant PAEs in fish. The PAEs concentration in demersal fish was significantly higher than that of pelagic fish, which may be attributed to the substantial contributions of shrimp (28.5 %) and POM (25.3 %) to the diet of demersal fish. This study provided new insights on the bioaccumulation of PAEs in dominant mangrove fish and confirmed that habitat preferences and food sources could significantly influence the bioaccumulation of PAEs in fish.

Spatial variations of annual net ecosystem productivity and its trend over Chinese terrestrial ecosystems based on spatial downscaling.

Annual net ecosystem productivity (NEP), the amount of net carbon sequestration during a year, serves as the basis of terrestrial carbon sink. Quantifying the spatial variations of NEP and its trend would enhance our understandings on the response and adaption of ecosystems to environmental change, which also serves for the regional carbon management targeting at carbon neutrality. Based on process-based model and data-driven model simulating NEP, we selected the optimal simulating NEP mostly representing NEP spatial variations with multiple site eddy covariance measurements to develop the spatial downscaling method and generate high resolution NEP data of China, which was used to examine the spatial variations of NEP and its trend and driving factors during 2000-2017. Compared with process-based model results, data-driven model simulating NEP could mostly represent the spatial variation of site measurements. The random forest regression based on climate, soil, and biological data combining with the simple scaling could successfully downscale NEP to a high spatial resolution. From 2000 to 2017, the total amount of NEP in China was (1.30±0.03) Pg C·a-1, showing a decreasing-increasing pattern with the inflection point in 2009. Chinese NEP decreased from southeast to northwest, showing a descending latitudinal distribution and an ascending longitudinal distribution, with the combined effects of climate and biotic factors. NEP trend decreased from east towards west, which was only accompanied with a slightly ascending longitudinal distribution, while photosynthetically active radiation and soil organic carbon content dominated the spatial variations of NEP trend. Therefore, the spatial patterns of generated NEP obviously differed from those of NEP trend, suggesting the obvious difference between the responses and adaptions of ecosystems to environmental changes.

High heat tolerance and thermal safety margins in mangroves from the southwestern coast of India

Mangroves are key components of productive ecosystems that provide a multitude of ecosystem goods and services. How these species will respond to future climates with more frequent and severe extreme temperatures has not received much attention. To understand how vulnerable mangroves are to future warming, we quantified photosynthetic heat tolerance and estimated thermal safety margins for thirteen mangrove species from the southwestern Indian coast. We quantified heat tolerance as temperatures that resulted in a 5 % (T5) and 50 % (T50) decline in photosystem II function, and thermal safety margins (TSM) as the difference between T50 and maximum leaf temperatures. T50 ranged from 48.9 °C in Avicennia Marina to 55.3 °C in Bruguiera gymnorhiza, with a mean of 53.3 °C for the thirteen species. Heat tolerance was higher for species with bigger leaves which experience higher leaf temperatures, but was not related to the other leaf traits examined. Heat tolerance was exceptionally high in these mangroves compared to other woody species. With their high tolerance and large safety margins these mangroves may be relatively less vulnerable to future climates with higher temperatures.

SOCIOCULTURAL VALUATION OF ECOSYSTEM SERVICES OF THE BAJO SINÚ MARSH COMPLEX IN THE DEPARTMENT OF CÓRDOBA, COLOMBIA

Wetlands are one of the most productive ecosystems on earth; however, they are threatened by multiple factors. Despite society's interdependence and continuous interaction with these ecosystems, they are often overlooked in management and decision-making. Therefore, this research aims to socially value the Bajo Sinú Marsh Complex (Marshes: Momil, Zapal, and Guartinaja) according to the importance that the local community and experts place on the ecosystem services they provide. For its development, an environmental characterization was carried out, covering the biophysical and social dimensions. Subsequently, different ecosystem services validated with professionals were identified and then valued through semi-structured surveys and analyzed using statistical software such as SPSS. The results show that, for the community, the most important ecosystem services are cultural (35.86%), regulation (33.72%), and provisioning (30.42%), while experts rank regulation as the most important (36.3%), followed by cultural services (35.1%) and provisioning (28.6%). The results provide a necessary knowledge base for the analysis of the use and exploitation of services, as well as for developing guidelines for the sustainable management of the resources provided by these wetlands.

Effects of Biophysical Factors on Light Use Efficiency at Multiple Time Scales in a Chinese Cork Oak Plantation Ecosystem

Light use efficiency (LUE) characterizes the efficiency of vegetation in converting photosynthetically active radiation (PAR) into biomass energy through photosynthesis and is a critical parameter for gross primary productivity (GPP) in terrestrial ecosystems. Based on the eddy covariance measurements of a Chinese cork oak plantation ecosystem in northern China, the temporal variations in LUE were investigated, and biophysical factors were examined at time scales ranging from hours to years. Our results show that diurnal LUE first increased sharply before 8:30 and then decreased gradually until 12:00, thereafter increasing gradually and reaching the maximum value at sunset during the growing season. The daily and monthly LUE first increased and then decreased within a year and showed a substantial drop around June. The annual LUE ranged from 0.09 to 0.17 g C mol photon−1, and the multiyear mean maximal LUE was 0.30 g C mol photon−1 during 2006–2019. Only GPP (positive) and clearness index (CI) (negative) had consistent effects on LUE at different time scales, and the effects of the remaining biophysical factors on LUE were different as the time scale changed. The effects of air temperature, vapor pressure deficit, precipitation, evaporative fraction, and normalized difference vegetation index on LUE were mainly indirect (via PAR and/or GPP). When CI decreased, an increased ratio of diffuse PAR to PAR produced a more uniform irradiance in the canopy, which ultimately resulted in a higher LUE. Due to climate change in our study area, the annual LUE may decrease in the future but improving management practices may slow or even reverse this trend in the annual LUE in the studied Chinese cork oak plantation.

Exploring the Influencing Factors of Net Ecosystem Productivity (NEP) Based on Random Forest and SHAP

As global climate change intensifies, Net Ecosystem Productivity (NEP) serves as a crucial indicator for measuring the carbon absorption and release of ecosystems, playing a vital role in understanding the carbon cycle and shaping climate policy. The Northwestern region of China, characterized as a typical inland arid and semi-arid area, is particularly sensitive to global changes. Understanding the environmental drivers of NEP in this region is critical for both regional ecological protection and global environmental management. This study utilized environmental data from five provinces in Northwestern China, applying the Random Forest (RF) model and SHapley Additive exPlanation (SHAP) method to analyze the primary environmental factors influencing NEP. The research integrated climatic data (including temperature, precipitation, wind speed, and solar radiation), soil characteristics such as pH, organic carbon content, and soil texture, topographic attributes elevation and slope, and a Human Footprint. The RF model identified significant environmental factors impacting NEP, and SHAP values were used to explain the specific contributions of these factors. Furthermore, multiple linear regression analysis revealed interactions among environmental factors. The results indicate that solar radiation (Srad), precipitation, topsoil reference bulk density (T_REF_BULK), temperature, and the topsoil clay fraction (T_CLAY) significantly influence NEP. Notably, interactions between aspect and T_CLAY, aspect and T_REF_BULK, as well as the human footprint (HFP) and Srad, also show significant impacts on NEP. This study confirms that solar radiation, precipitation, soil characteristics, and human activities are the primary environmental drivers of NEP in the Northwest region of China, with solar radiation playing the most critical promotional role. The findings not only provide a scientific basis for the management of ecosystems in Northwestern China but also offer references for formulating global climate change mitigation strategies and estimating the global carbon budget. Future research should further explore the specific mechanisms and interactions of these drivers across different ecosystems to more comprehensively understand and predict the trends in NEP changes.

Insights into prokaryotic communities and their potential functions in biogeochemical cycles in cold seep.

Deep-sea cold seeps are among the most productive ecosystems, sustaining unique fauna and microbial communities through the release of methane and other hydrocarbons. Our study revealed that the influence of seepage fluid on the prokaryotic community in the water column is surprisingly limited, which challenges conventional views regarding the impact of seepage fluids. In addition, we identified that different DOM compositions play a crucial role in shaping the prokaryotic community composition, providing new insights into the factors driving microbial diversity in cold seeps. Furthermore, the study highlighted Proteobacteria as key and multifaceted drivers of biogeochemical cycles in cold seeps, emphasizing their significant contribution to complex interactions and processes. These findings offer a fresh perspective on the dynamics of cold-seep environments and their microbial communities, advancing our understanding of the biogeochemical functions in deep-sea environments.

Exploring Community-Supported Agriculture through Maslow’s Hierarchy: A Systematic Review of Research Themes and Trends

Community-supported agriculture (CSA) has emerged as a pivotal model for sustainable and humanistic agricultural practices, emphasizing the symbiotic relationship between food production, consumption, and sustainable ecosystems. Despite the growing interest, a comprehensive analysis of research themes and trends within the CSA framework remains sparse. This paper undertakes a systematic review of CSA literature from 1999 to 2023, identifying evolving research hotspots, dominant themes, and prospective directions by keyword analysis to corroborate Maslow’s hierarchy of needs theory. The research analysis location is categorized into four temporal phases, revealing a geographical expansion from North America to encompass Asia, Africa, and other continents. This expansion corroborates Maslow’s theory, illustrating a global shift from fulfilling basic physiological needs towards recognizing sustainable practices, particularly in developing regions. The results of temporal trends (5 phases) and the hotspots of keyword analysis support each other by showing a societal shift from basic sustenance to a deeper understanding of nutrition and diet. Most of the recent research keywords are grouped into the “environment” and “health and education” categories, indicating an increasing emphasis on transforming the food system and nutrition education. This review suggests conducting an integrated analysis that links the various stages of the food supply chain with the criteria outlined in the Sustainable Agriculture Matrix (SAM). It highlights that the “environment” theme is a stage of building up esteem and self-realization that needs to be unfolded in the future, given that most research on community-supported agriculture (CSA) focuses on the “economy and society” aspect and consumption stage, which burnish self-morality in the theory of Maslow. Overall, this review proposes an analysis of the relevance among different subject categories and between food supply chain stages, which reveals that the trend of research under CSA development is accorded to the theory of Maslow’s hierarchy of needs and calls for a more holistic approach to agricultural research that considers ecological, health, and social imperatives.

Trends in the Research and Development of Soil Nitrogen Mineralization in Forests from 2004 to 2024

Nitrogen (N) is a vital mineral nutrient for plant growth and occupies a pivotal position in biogeochemical systems. Soil nitrogen mineralization (SNM) in forests represents a significant limiting factor in terrestrial ecosystem productivity in the context of global climate change. To understand the research status and development trends of SNM in forests, 3576 articles spanning 2004 to 2024 from the Web of Science (WOS) database were analyzed using CiteSpace software. The results indicated that (1) the mean number of articles published in the recent ten-year period is 193, marking an approximate 17.8% increase compared to the preceding ten-year period (2004–2013), highlighting the continuous development of SNM research; (2) among the sampled articles, Soil Biology and Biochemistry, Forest Ecology and Management, Plant and Soil, and Biogeochemistry emerged as leading international journals that played a key role in shaping the development of the field and laid a solid foundation for future research efforts; (3) the USA and China emerged as the most productive countries in this field, with the Chinese Academy of Sciences standing out as a prominent institution at the forefront of this research domain; and (4) recent research is focusing on understanding the interactions between microbial communities and the environment during SNM. In summary, this study offers valuable insights into the research status and development trends of SNM in forests. It underscores the importance of ongoing interdisciplinary collaboration and innovation to further enhance our understanding of key ecological processes. Future research on SNM in forests is encouraged to delve deeper into its associations with forest productivity, carbon cycling, microbial functions, and global change. Additionally, exploring sustainable land management and process optimization is recommended to promote the healthy and sustainable development of forest ecosystems.

Changing circulations challenge the sustainability of cold water mass and associated ecosystem under climate change

Bottom cold water mass provides abundant nutrients and cool water in summer, playing a pivotal role in the productivity of marine ecosystem and sustainable aquaculture development. Located in the most densely populated region, the Yellow Sea cold water mass (YSCWM) is a unique one influencing hundreds of millions of people living in the rim of the Yellow Sea. As anthropogenic carbon emissions continue, how the YSCWM will be altered by climate change becomes a pressing issue, but remains elusive. Using an unprecedented set of climate models with high resolution and biogeochemical components, we find that the volume of the YSCWM will shrink by 48% to 2040–2050, along with the bottom temperature warming of 0.4 ± 0.1 °C dec−1 and the dissolved oxygen concentration declining of 0.09 ± 0.04 mg (L dec)−1. The significant destruction of the YSCWM is driven by the strengthened Yellow Sea Warm Current (YSWC). The reduced land-sea thermal contrast is the cause of the circulation change, by weakening the East Asian winter monsoon. Due to the resultant profound habitat reduction for marine life, predicting the change of the YSCWM will have far-reaching influences on the future policy-making for sustainable development of offshore aquaculture.

Landscape patterns of carbon fluxes in natural and disturbed ice-wedge-polygon tundra

ABSTRACT The degradation of ice-rich permafrost ecosystems due to climate change and infrastructure development strongly impacts carbon exchange dynamics in tundra landscapes. This study investigates the effects of surficial geology and infrastructure disturbances from road dust and flooding on vegetation and trace gas fluxes in polygonal ice-wedge tundra in arctic Alaska. We compared CO2 and CH4 fluxes from closed-chamber measurements at common landform elements (polygon centers, troughs, and rims) at a natural site and a disturbed site within the Prudhoe Bay Oil Field. Relationships among environmental parameters, plant species composition, and trace gas fluxes were assessed through nonmetric multidimensional scaling. Map extrapolations showed spatial variations in midsummer landscape-level ecosystem productivity and CH4 efflux at the various geologic landforms. Highest carbon uptake occurred in ice-rich drained thaw lake basins with aquatic, graminoid-dominated polygon troughs. In contrast, wet, featureless areas associated with more recently drained, ice-poor thaw lake basins showed a net carbon loss even during summer. The damming effect of road infrastructure led to deeply flooded, minimally vegetated troughs with low ecosystem respiration and high CH4 fluxes close to the road. This work highlights the importance of the complex interactions among surficial geology, landform elements, vegetation type, and disturbance factors in understanding carbon exchange dynamics in ice-rich permafrost environments.

From resources to capital: Investigating the efficiency of forest ecosystem products value realization in China

Forest resources provide a good ecological environment for human beings and offer economic well-being and benefits. Value realization of ecosystem products reflects the process from resources to capital. This study investigates the two-stage value realization efficiency of China's forest ecosystem products from 2011 to 2021. A parallel nested network Data Envelopment Analysis model is applied to assess product supply and value transformation stages. In addition, the evolution of the spatial pattern is depicted by a multilayer Standard Deviational Ellipse. The results reveal that (1) the overall value realization trend of China's forest ecosystem products shows a fluctuating growth trend, with an average annual efficiency value of 0.86. (2) The efficiency level of the value transformation stage is lower than that of the product supply stage. (3) Regional disparities persist. The efficiency values in East China and South China are higher than that in other regions. (4) The value realization capacity of China's forest ecosystem products may be closely related to national development strategies and policy orientations.

Deciphering the differences of bacterial communities between high- and low-productive wheat fields using high-throughput sequencing.

Microbial communities have been demonstrated to be essential for healthy and productive soil ecosystems. However, an understanding of the relationship between soil microbial community and soil productivity levels is remarkably limited. In this study, bulk soil (BS), rhizosphere soil (RS), and root (R) samples from the historical high-productive (H) and low-productive (L) soil types of wheat in Hebei province of China were collected and analyzed by high-throughput sequencing. The study highlighted the richness, diversity, and structure of bacterial communities, along with the correlation networks among different bacterial genera. Significant differences in the bacterial community structure between samples of different soil types were observed. Compared with the low-productive soil type, the bacterial communities of samples from the high-productive soil type possessed high species richness, low species diversity, complex and stable networks, and a higher relative abundance of beneficial microbes, such as Pseudoxanthomonas, unclassified Vicinamibacteraceae, Lysobacter, Massilia, Pseudomonas, and Bacillus. Further analysis indicated that the differences were mainly driven by soil organic matter (SOM), available nitrogen (AN), and electrical conductivity (EC). Overall, the soil bacterial community is an important factor affecting soil health and crop production, which provides a theoretical basis for the targeted regulation of microbes in low-productivity soil types.

Substantial nitrogen abatement accompanying decarbonization suppresses terrestrial carbon sinks in China

China faces challenges in reaching its carbon neutrality goal by the year 2060 to meet the Paris Agreement and improving air quality simultaneously. Dramatic nitrogen emission reductions will be brought by this ambitious target, yet their impact on the natural ecosystem is not clear. Here, by combining two atmospheric chemistry models and two process-based terrestrial ecosystem models constrained using nationwide measurements, we show that atmospheric nitrogen deposition in China’s terrestrial land will decrease by 44–57% following two emission control scenarios including one aiming at carbon neutrality. They consequently result in a pronounced shrinkage in terrestrial net ecosystem production, by 11–20% depending on models and emission scenarios. Our results indicate that the nitrogen emission reductions accompanying decarbonization would undermine natural carbon sinks and in turn set back progress toward carbon neutrality. This unintended impact calls for great concern about the trade-offs between nitrogen management and carbon neutrality.

Plant functional trait is a strong predictor of ecosystem productivity under altered precipitation in desert steppes

AbstractThe relationship between biodiversity and ecosystem function has always been one of the hot issues in the field of ecology. With the acceleration of global warming, the precipitation pattern has become one of the main drivers of biodiversity loss, which has a profound impact on ecosystem functional services and stability. However, the studies on the effects and mechanisms of plant community diversity and ecosystem productivity under precipitation changes in desert steppe are still unclear. According to the change rate (−41.1% to 39.2%) of precipitation in the study area in recent 50 years, five precipitation gradients (i.e., −40%, −20%, CK, +20% and +40%) were set to simulate the possible future precipitation pattern changes. Aboveground biomass increased with the increase of precipitation. Compared with CK, the aboveground biomass increased by 22.81% with +40% and decreased by 80.71% with −40%, and the negative impact of precipitation decrease on aboveground biomass was more significant. Through multiple stepwise regression analyses, species diversity, functional diversity and phylogenetic diversity were identified as the best models of aboveground biomass. The results showed that the aboveground biomass changes could be explained by 51.3%, 81.6%, 32.6% and 60% respectively. Combined with plant community diversity, the final index model was obtained through multiple stepwise regression analyses, which could explain 88.3% of changes in aboveground biomass. In this model, The average coefficient of specific leaf area and leaf thickness had a very high significance level, and these two functional traits of dominant species had a greater explanatory power for ecosystem system function. There was a nonlinear correlation between precipitation and aboveground biomass, and drought had a more significant negative effect on aboveground biomass. Compared with species diversity and phylogenetic diversity, plant functional traits can better explain ecosystem productivity. Selection effects are the main maintenance mechanism of desert steppe community productivity under the background of precipitation change.