Ecosystem Quality Research Articles

Analysis of the Characteristics Aquatic Ecosystem Poso Energy Hydropower Plant in Lake Poso Central Sulawesi

It is feared that the use of the Poso Energy Hydroelectric Power Plant (PLTA) and various industrial, agricultural, and domestic waste disposal activities can reduce the quality of Poso Lake waters. Until now, studies on the impact of PLTA on waters quality have never been carried out. This study aims to analyze the characteristics of the ecosystem quality of Lake Poso waters based on phisical, chemical, and biological parameters. The research was conducted using the sampling method at 6 location points in the area before the PLTA, around the PLTA, and after the PLTA from July to September 2022. Data were analyzed statistically with ANOVA. The results showed that phisical parameters (TSS, odor, colour, turbidity), chemical (pH, DO, BOD, COD, NO3-N, total phosphate), and biological (fecal coliform, plankton diversity) showed significantly different values in the area before PLTA, around PLTA, and after the PLTA. The existence of PLTA is concluded to have an impact on changes the waters quality. A management strategy that accomodates more environmental factors is needed to ensure the sustainability of Lake Poso aquatic resources.

Evaluation and driving force analysis of ecological environment in low mountain and hilly regions based on optimized ecological index.

In low mountain and hilly regions, vegetation cover is higher and plant growth has an accumulative effect, sequestering carbon more strongly. The traditional remote sensing based ecological index (RSEI) lacks the consideration of vegetation productivity, and using it to evaluate ecological environment in low mountain and hilly regions will be biased. In this study, the vegetation productivity was introduced to construct a natural remote sensing based ecological index (NRSEI) that responds to the low mountain and hilly regions, as an example of Gaizhou City, China. Additionally, this study explored the spatiotemporal evolution of ecological environment quality from 2014 to 2020 and quantified the influences of factors. The results show that the first principal component (PC1) increased from 56 to 67% to 65-87% and considered the accumulation process in the ecosystem. NRSEI was more valid. From 2014 to 2020, the quality of the ecological environment generally declined and then increased. The area with "Excellent" increased from 23 to 38%. The quality of ecosystems in the west, northwest, and south deteriorated significantly, a distribution pattern of "high in the center, low in the north and south". Landuse and topographic conditions dominate the impacts on the ecosystem in the context of social, economic and policy influences. The interactions of the factors were two-factor enhancement that together affect the ecological environment. The results contribute to the development of urban conservation policies in low mountain and hilly regions.

Improvement of water quality through coordinated multi-trophic level biomanipulations: Application to a subtropical emergency water supply lake

Artificial emergency water source lakes have been built in most cities in the middle and lower reaches of the Yangtze River, China, to ensure water safety for residents. However, these new ecosystems are prone to algal blooms or other degraded water quality conditions. A newly built water supply lake in the lower reaches of the Yangtze River was selected as a model system to test whether the coordinated manipulation of fish and submerged macrophyte communities could enhance ecosystem function and quality. The coordinated manipulations spanned a five-year period, aiming to enhance both top-down and bottom-up control of phytoplankton. As a result of these manipulations, the catch per unit effort of small-bodied zooplanktivorous fishes decreased by >95 % from year two and remained low. The coverage and biomass of submerged macrophytes increased year by year. Water transparency increased from 1.07 to 3.33 m. Total phosphorus and total nitrogen showed a decreasing trend (not significant though). The annual mean biomass of Cyanophyta, Chlorophyta and Bacillariophyta decreased from 2.99 to 0.03 mg/L, 3.90 to 0.16 mg/L, and 3.50 to 0.3 mg/L, respectively. The biomass of phytoplankton in different groups decreased in all four seasons. The annual mean biomass of Cladocera and Copepoda remained low. The biomass of Cladocera and Copepoda decreased in summer, fall, and winter. The Ecosystem Health Index - increased from 15.9 to 32.0. The pros and cons of the various top-down and bottom-up control measures employed are discussed. This research presents a valuable case study on the enhancement of ecosystem structure and function in newly constructed emergency water supply lakes and offers insights into the restoration of other subtropical shallow lakes.

Odonata assemblages at two urban wetlands in West Bengal, India

Adult Odonata represent valuable indicators of natural habitat quality, ecosystem integrity, and pollution status in freshwater ecosystems. This study aimed to investigate how varying climatic condition, sub-habitat types, and physicochemical ambience of wetlands impact Odonata diversity. We compared the abundance and richness of Odonata in two urban wetlands and their surrounding areas: Purulia Sahebbandh (PS) located amidst Purulia town and faced higher anthropogenic threats, and Adra Sahebbandh (AS) located in a slightly remote location. Sampling was conducted over a period of one year (December 2018 to November 2019) using the Pollard walk method and direct search technique. A total of 47 Odonata species were recorded, including 33 species of dragonflies (Anisoptera) and 14 species of damselflies (Zygoptera). AS exhibited significant higher overall abundance compared to PS, with the monsoon season showing the highest abundance in both wetlands. Water-associated vegetation zones harbored the highest species richness. Species richness and abundance significantly differed among most of the sub-habitat types. Physicochemical factors such as pH, electrical conductivity, salinity, nitrate and phosphate concentrations, and dissolved oxygen significantly influenced Odonata abundance and species richness. The urban location, pollution load, and lack of natural vegetation in PS’s surrounding areas likely contributed to the lower Odonata abundance. Implementing sustainable management measures for wetlands and their surroundings is crucial to enhancing ecosystem services and supporting Odonata populations.

Windthrow in riparian buffers affects the water quality of freshwater ecosystems in the eastern Canadian boreal forest

Despite the wide application of riparian buffers in the managed boreal forest, their long-term effectiveness as freshwater protection tools remains unknown. Here, we evaluate windthrow incidence in riparian buffers in the eastern Canadian boreal forest and determine the effect of windthrow on the water quality index of the adjacent freshwater ecosystems. We studied 40 sites—20 riparian buffers, aged 10 to 20 years after harvesting and 20 control sites within intact riparian environments—distributed among clay and sandy (esker) soils and black spruce (Picea mariana) and jack pine (Pinus banksiana) stands. We observed more windthrow in the harvested stands (36%) relative to the control sites (16%), regardless of substrate and species. We determined that the most important factors explaining windthrow were exposition, harvesting, aquatic environment size, and stand characteristics. These factors drive wind exposure, speed, and force, which determine post-harvest windthrow risk. Furthermore, windthrow negatively affected the water quality index of the adjacent aquatic systems, i.e., greater windthrow decreased the protective effect of the riparian buffer. We recommend increasing the use of partial harvest near riparian environments and adapting riparian buffers to site conditions to ensure the long-term protection of adjacent freshwater ecosystems.

Life cycle assessment of common urban trees - The environmental performance of three Mediterranean cities

Given the increasing pressure from extreme events due to climate change, the planting of new trees has become a priority in the political agendas of cities. However, the rush to plant trees often fails to account for the reduced performance and lifespan of trees in heavily urbanized areas and the environmental impact of their production, maintenance, and eventual disposal. By means of the Life Cycle Analysis, this study aims to investigate the potential environmental benefit and impact of trees planted in three European cities located in Mediterranean areas (Perugia, Thessaloniki, and Cascais), that have adhered to the management guidelines of the LIFE Clivut project. The environmental performance of each tree is mainly affected by the tree management operations performed, by the climatic conditions, and by the tree performance in carbon dioxide (CO2) uptake and Particulate matter (PM) capture. The impact assessment obtained by ReCiPe 2016 Endpoint (H) methodology evidenced that the trees' beneficial effects widely overcome the impact of the operations carried out during the tree management. Broadleaved species showed an average environmental performance higher than conifers. The best results have been obtained by Tilia cordata Mill., Quercus ilex L., Populus spp. and Celtis australis L. in the case of broadleaved trees, and by Calocedrus decurrens (Torr.) Florin and Cedrus spp. for Conifers. The results of the Environmental Footprint (EF 3.1) method highlighted the urban trees' potentiality to mitigate Human Health problems and to improve Ecosystem Quality. Future studies may explore other management scenarios to optimize energy and materials use, reduce emissions, hence obtaining an increase of the environmental benefit for the urban areas.

Ecological Effects of the Huge Invasive Species Removal Project in Coastal China.

Saltmarsh wetlands are recognized as some of the most ecologically valuable yet vulnerable ecosystems globally. However, since the 1970s, saltmarsh wetlands in coastal China have been seriously threatened by the invasive Spartina alterniflora. Although the Chinese government has initiated a nationwide S.alterniflora removal project, the potential benefits and risks of this project remain unknown. Here, we focus on the Yangtze River Estuary Saltmarsh Wetland (YRESW) and simulate its future ecosystem structure, function, and quality under three scenarios based on remote sensing and field investigation data. The simulation scenarios include the absence of a removal project, natural regeneration postproject (NRP), and planted restoration postproject. The results show that the removal project will reverse the escalating invasion trend of S.alterniflora in the YRESW. Compared to the baseline year of 2022, there is a remarkable increase in ecosystem structure (composition: +107%, configuration: +27%) and ecosystem quality (+10.5%) under the NRP scenario. Although blue carbon storage sharply decreases under both scenarios involving project implementation, planted restoration can restore YRESW's carbon sequestration capacity to 0.19 Tg C per year, achieving 87% of the carbon storage present before the project. This study underscores the necessity of comprehensive and detailed risk assessments in ecological projects, particularly when dominant species are involved. Our findings hold significant implications for stabilizing coastal wetland ecosystems and promoting sustainable development in coastal areas.

Assessing the sustainability and safety of Polyethylene Terephthalate (PET) liners for Lead Service Lines (LSL) Upgrades

Polyethylene Terephthalate (PET) liners have been proposed by industry as a more cost effective and less disruptive alternative to lead service lines (LSL) replacement. However, concerns have been raised about their aging under real-use conditions and their potential health and environmental impacts. In this study, two approaches were implemented. First, bench and pilot scale experiments were carried out to investigate the aging of a PET liner under conditions that simulate normal usage. Results show early surface oxidation and leaching of potentially hazardous metals (lead, zinc and titanium). No short-term fragmentation of the PET liner into microplastics was observed. Next, a life cycle assessment (LCA) compared the health and environmental impacts of three LSL upgrades alternatives: PET liners and full LSL replacement using either copper or PEX pipes. The installation phase was shown to be the main contributor to impact scores, while the benefits of PET liners are highly dependent on its lifespan. PEX installed by torpedoing lowers impacts as compared to PET liners and copper pipes for equal lifespan, while the use of PET liners remains less impactful regarding human health and ecosystem quality when a complete excavation is needed. LCA derived global human health effects due to ingestion of leached metals from PET liners, copper pipes, and unreplaced LSL and showed that PET liners and copper pipes significantly reduce health impacts by 14 and 80 DALY respectively compared to unreplaced LSL. Finally, the Integrated Exposure Uptake Biokinetic (IEUBK) model was used to assess the impact of lead exposure specifically for drinking water ingestion. Estimated Blood Lead Levels (BLL) in children and infants in households with long unreplaced LSL was up to 263.7% and 207.8% greater compared to either replacement with copper pipes or rehabilitation with PET liners, showing the clear benefits of corrective action. Combining experimental results, LCA and biokinetic modelling provides actionable information for utilities to select the best upgrade options, considering environmental, health and practical constraints, whilst identifying remaining data gaps. The relative benefits of the PET liner should be carefully evaluated considering its lifespan under real-life conditions, the complete replacement costs after failure, and the growing evidence of micro- and nanoplastics (MNP) risks.

Valorization of phosphate mine waste rock as alternative aggregates for high-performance concrete

Natural aggregate quarrying significantly impacts the environment while phosphate mine waste rock (PMWR) offers alternative aggregates for use in high-added value construction materials. This study was the first to investigate the application of three aggregate types from PMWR as a complete substitute to natural aggregate to produce high-performance concrete (HPC). For this aim, three coarse aggregate (CA) types: Flint (F), Phosflint (PF), and Dolomite (D) from PMWR in Morocco were selected and compared with a natural Reference CA (R). Two mixtures were tested: HPC-0.40 and HPC-0.36 with a w/c ratio equal to 0.40 and 0.36. D-HPC and PF-HPC achieved a slump exceeding 20 cm and a 28-d compressive strength (CS) equal to 55 MPa ± 5 MPa on average, similar to the R-HPC, while F-HPC did not meet the requirement for HPC (i.e. a 28-d CS superior to 55 MPa). Scanning electron microscope observations showed that D-HPC exhibited a very dense and indistinguishable interfacial transition zone (ITZ), while F-HPC showed a debonding of F-CA and a larger ITZ size which explain its lower CS. Life ycle assessment revealed a major positive environmental impact on ecosystem quality that reduced land occupation and land transformation by up to 32 %. A secondary evaluation of the valorization of PMWR as alternative fine aggregate (FA) in high-strength mortar (HSM) was investigated and showed that the 28-d CS is equal to 93 MPa for PF-HSM and equal to 81 MPa for D-HSM, superior to RS-HSM which is equal to 61 MPa. Dolomite and Phosflint FA offered a better alternative to natural River sand to overcome the ceiling effect. These findings encourage the construction sector to adopt a sustainable consumption of aggregates by using PMWR as alternative CAs and FAs to produce high-strength construction materials.

Analysis of Spatial and Temporal Variation of Water Quality: A Case Study of Kotagala Wetland, Nuwara Eliya, Sri Lanka

Water quality of wetland ecosystems is a critical concern due to its implications on human health and aquatic life. This study was conducted to assess the spatial and temporal variation of water quality in Kotagala wetland to understand its impact on water safety for domestic uses and ecosystem health. Water samples were collected (n = 70) from six inlets and the wetland outlet from November 2021 to August 2022, and analyzed for pH, electrical conductivity (EC), salinity, total dissolved solids (TDS), total suspended solids (TSS), nitrate, and phosphate. The pH, EC, and nitrate showed significant correlations. Spatial clustering divided the monitoring sites into two clusters, as areas of higher and lower pollution levels. Discriminant analysis highlighted the significance of EC, pH, and nitrate concentrations in differentiating these clusters. Principal According to principal component analysis (PCA) 88.8% of the total variance of spatial variation in water quality was explained by the first two components. Temporal clustering following seasonal variations revealed the influence of rainfall pattern on water quality. EC, TDS, TSS, and nitrate concentrations emerged as the most important factors in this temporal categorization. In PCA, 76.8% of the total variance of temporal variation in water quality was explained by the first two components. Findings highlight the urgent need for sustainable strategies and policies to mitigate the impacts of human activities on wetland water quality, since water quality variations in the wetland was significantly impacted by direct human activities, and variations in rainfall trends in the area.

Assessing the sources and spatiotemporal variability of dissolved trace elements in the upper Nakdong River based on multivariate analysis

Various sources associated with mining activities adversely affect water quality in aquatic ecosystems. This study aimed to estimate the sources of dissolved trace elements (DTEs: Al, As, B, Ba, Cd, Co, Cr, Cs, Cu, Fe, Li, Mn, Mo, Ni, Pb, Rb, Sb, U, and Zn) affecting water chemistry in the upper Nakdong River (UNR) catchment and determine the hydrological processes associated with the inflow from anthropogenic sources. Hierarchical cluster analysis (HCA) and principal component analysis (PCA) were employed to estimate main sources affecting water chemistry and its spatiotemporal variability in the four tributaries and main channel of the UNR. Water samples were classified into four groups based on their chemistry. The spatiotemporal variations of DTEs were driven by the presence of anthropogenic sources (including smelters, AMD, mining-related sources), while running toward downstream. The correlations among PCA (and HCA), Zn as smelter impact, and deuterium excess (d-excess = δ2H – 8 × δ18O) indicated that smelters had a strong influence on water chemistry in the main channel after passing through the smelter. In the dry season, d-excess < ~12 ‰ was observed with increasing Zn levels and factor score for PC2, especially samples influenced by DTEs from smelter, indicating that groundwater affected by the smelters recharged mainly by summer rainwater impacted the spatiotemporal variability of DTEs. This multivariate study suggests that the spatiotemporal variation in DTEs is associated with the complex contributions of natural and anthropogenic sources to water chemistry, which are strongly influenced by hydrological processes and seasonality.

Economic optimization of sustainable soil management: a Dutch case study

Soil quality is pivotal for crop productivity and the environmental quality of agricultural ecosystems. Achieving sufficient yearly income and long-term farm continuity are key goals for farmers, making sustainable soil management an economic challenge. Existing bio-economic models often inadequately address soil quality. In this study, we apply the novel FARManalytics model, which integrates chemical, physical, and biological indicators of soil quality indicator, quantitative rules on how these indicators respond to farmers’ production management over time, and an economic calculation framework that accurately calculates the contribution of production management decisions towards farm income. This is the first study applying this model on existing arable farms. FARManalytics optimizes crop rotation design, cover crops, manure and fertilizer application and crop residue management. Nine Dutch arable farms were analyzed with a high variation in farm size, soil type, and cultivated crops. First, we assessed farm differences in soil quality and farm economics. Second, we optimized production management to maximize farm income while meeting soil quality targets using farm-specific scenarios. Third, we explored the impact of recent policy measures to preserve water quality and to increase the contribution of local protein production. The results show that the case farms already perform well regarding soil quality, with 75% of the soil quality indicators above critical levels. The main soil quality bottlenecks are subsoil compaction and soil organic matter input. We show that even in front-runner farms, bio-economic modeling with FARManalytics substantially improves economic performance while increasing soil quality. We found that farm income could be increased by up to €704 ha−1 year−1 while meeting soil quality targets. Additionally, we show that to anticipate on stricter water quality regulation and market shift for protein crops, FARManalytics is able to provide alternative production management strategies that ensure the highest farm income while preserving soil quality for a set of heterogenous farms.

Ecotoxicity of alkaline residue from the pulp and paper industry to soil faunal organisms

The increased production and expanding demand for cellulosic products have required companies to provide solutions for the proper disposal of generated residues without compromising soil quality. In this context, the current research aimed at evaluating the ecotoxicological impacts of dregs application in subtropical soils. The experiments were carried out with the earthworm Eisenia andrei, the springtail Folsomia candida, and the potworm Enchytraeus crypticus in two subtropical soils (Neosol and Cambisol) collected in the southern region of Brazil. The considerable differences in texture and organic matter content motivated the choosing of these soils. The reproductive rate of all organisms was influenced, with varying EC50 values depending on the soil type. However, more pronounced effects were observed for Neosol. The springtail F. candida proved to be the most sensitive to contamination (EC50 = 5.8 g kg−1 for Neosol and 48.5 g kg−1 for Cambisol), followed by the earthworm E. andrei (EC50 = 62.4 g kg−1 for Neosol and 129.5 g kg−1 for Cambisol) and the potworm E. crypticus (EC50 = 67.2 g kg−1 for Neosol and 230.4 g kg−1 for Cambisol). As a result, while dregs can be used to correct soil acidity, they have been shown to have negative effects on important organisms responsible for functions critical to maintaining ecosystem quality.

Effects of woody debris on alluvial sediment differentiation and particulate organic matter accumulation in a mountainous forest stream in the Polish Carpathians

Woody debris (WD) stabilizes riverbeds, creates habitats, supports biodiversity, and enhances water quality in ecosystems. This study investigates the impact of WD on sediment characteristics and particulate organic matter (POM) accumulation in the Roztoka stream, located within a forested catchment in the Polish Carpathians. The focus is on the influence of different WD types: coarse (CWD, length &amp;gt; 1 m and diameter &amp;gt; 10 cm), fine (FWD, length &amp;lt; 1 m and diameter &amp;lt; 10 cm), and mixed (MWD, a combination of CWD and FWD) on sediment differentiation and POM accumulation. Stand age, ranging from 20 to over 120 years (in 20-year intervals), was also analyzed as a factor affecting WD structure and POM deposition. Results indicate that MWD had the greatest effect on sediment differentiation, with mean grain size (Mz) ranging from −3.91 phi to −0.95 phi. Stand age significantly influenced POM accumulation, with the highest content (19.51%) observed in age classes III and VI. Older stands (&amp;gt; 120 years) had a diminished effect on both WD structure and POM accumulation. This study underscores the critical role of WD in sediment differentiation and provides insights for improving the ecological function of natural streams. Although the findings are region-specific, they have broader implications for similar temperate mountainous forests.

One century of carbon dynamics in the eastern Canadian boreal forest under various management strategies and climate change projections

Partial cutting has lower canopy removal intensities than clearcutting and has been proposed as an alternative harvesting approach to enhance ecosystem services, including carbon sequestration and storage. However, the ideal partial cutting/clearcutting proportion that should be applied to managed areas of the eastern Canadian boreal forest to enhance long-term carbon sequestration and storage at the landscape scale remains uncertain. Our study projected carbon dynamics over 100 years (2010–2110) under a portfolio of management strategies and future climate scenarios within three boreal forest management units in Quebec, Canada, distributed along an east–west gradient. To model future carbon dynamics, we used LANDIS-II, its Forest Carbon Succession extension, and several extensions that account for natural disturbances in the boreal forest (wind, fire, spruce budworm). We simulated the effects of several management strategies on carbon dynamics, including a business-as-usual strategy (clearcutting applied to more than 95 % of the annually managed area), and compared these projections against a no-harvest natural dynamics scenario. We projected an overall increase in total ecosystem carbon storage, mostly because of increased productivity and broadleaf presence under limited climate change. The drier Western region under climate scenario RCP8.5 was an exception, as stocks decreased after 2090 because of the direct negative effects of extreme climate change on coniferous species’ productivity. Under the natural dynamic scenario, our simulations suggest that the Quebec Forest in the Central and Western regions may act as a carbon sink, despite high fire-related carbon emissions, particularly under RCP4.5 and RCP8.5 Conversely, the eastern region periodically switched from carbon sink to source following SBW outbreaks, thus being a weak sink over the simulation period. Applying partial cutting to over 50 % of the managed forest area effectively mitigated the negative impacts of climate change on carbon balance, reducing differences in stand composition and carbon storage between naturally dynamic forests and those managed for timber. In contrast, clearcutting-based scenarios, including the business-as-usual approach, substantially reduced total ecosystem carbon storage— by approximately double (10 tC ha−1 yr−1) compared to partial cutting scenarios (<5 tC ha−1 yr−1). Clearcutting led to higher heterotrophic respiration due to the proliferation of fast-decomposing broadleaves, resulting in lower carbon accumulation compared to partial cuts. Our findings underscore the importance of balancing canopy removal intensities to increase carbon sequestration and storage while preserving other ecosystem qualities under climate change.

Do establishment of protected areas and implementation of regional policies both promote the forest NPP? Evidence from Wuyi Mountain in China based on PSM-DID

Establishing protected areas has been a longstanding strategy to conserve forests. Net Primary Productivity (NPP) offers a reflection of ecosystem quality and vegetation vitality compared to traditional spatial indicators, making it a valuable metric for evaluating conservation outcomes in protected areas. Additionally, there is a lack of knowledge about the concurrent influence of in situ conservation and pertinent policies on forest conservation. Through Propensity Score Matching (PSM) and the Difference-in-Difference (DID) model, we evaluated the conservation outcomes of NPP within protected areas and identified different policies’ impacts. Wuyi Mountain in China, known for its rich forest resources, was selected as the study area. The results revealed: (1) NPP within all protected areas fluctuated within a stable range from 1985 to 2021, with some exhibiting a significant upward trend; (2) A total of 62.5 % of protected areas demonstrated a positive effect on forest NPP. There is a 72 % effective conservation rate for nature reserves, one type of protected area in China, making them the most effectively protected in Wuyi Mountain; (3) In 50 % of the cases, the policies resulted in positive outcomes. The impact of policies on forest NPP varies across different types of protected areas; (4) Only 16.67 % of policy scenarios demonstrated a concurrent positive effect from both protected areas and conservation policies. By analyzing the impact of protected area establishment and conservation policy implementation on NPP, our research can offer valuable insights for policymakers aiming to enhance forest conservation in mountain areas.

An Evaluation of Ecosystem Quality and Its Response to Aridity on the Qinghai–Tibet Plateau

Exploring the response of spatial and temporal characteristics of ecological quality change to aridity on the Qinghai–Tibet Plateau (QTP) can provide valuable information for regional ecological protection, water resource management, and climate change adaptation. In this study, we constructed the Remote Sensing Ecological Index (RSEI) and Standardized Precipitation Evapotranspiration Index (SPEI) based on the Google Earth Engine (GEE) platform with regional characteristics and completely analyzed the spatial and temporal variations of aridity and ecological quality on the QTP in the years 2000, 2005, 2010, 2015, and 2020. Additionally, we explored the responses of ecological quality to aridity indices at six different time scales. The Mann–Kendall test, correlation analysis, and significance test were used to study the spatial and temporal distribution characteristics of meteorological aridity at different time scales on the QTP and their impacts on the quality of the ecological environment. The results show that the ecological environmental quality of the QTP has a clear spatial distribution pattern. The ecological environment quality is significantly better in the south-east, while the Qaidam Basin and the west have lower ecological environment quality indices, but the overall trend of environmental quality is getting better. The Aridity Index of the QTP shows a differentiated spatial and temporal distribution pattern, with higher Aridity Indexes in the north-eastern and south-western parts of the plateau and lower Aridity Indexes in the central part of the plateau at shorter time scales. Monthly, seasonal, and annual-scale SPEI values showed an increasing trend. There is a correlation between aridity conditions and ecological quality on the QTP. The areas with significant positive correlation between the RSEI and SPEI in the study area were mainly concentrated in the south-eastern, south-western, and northern parts of the QTP, where the ecological quality of the environment is more seriously affected by meteorological aridity.

Current status and research prospects of terrestrial ecosystem carbon sink in Northeast China.

Increasing the carbon sink capacity of terrestrial ecosystems is a primary strategy to mitigate climate change and achieve the "carbon neutrality" goal. Clarifying the status and future dynamics of carbon sink of terrestrial ecosystems in Northeast China is crucial for achieving "carbon neutrality" as this region is a core contributor to carbon sink in China's terrestrial ecosystems. Here, we systematically summarized current research on carbon sink of terrestrial ecosystems across Northeast China, including the measurements and spatial-temporal patterns of carbon sinks, driving mechanisms of carbon sinks, the assessments of carbon sink potential, and technologies for increasing carbon sequestration. There are substantial uncertainties in quantifying terrestrial ecosystem carbon sink in Northeast China due to differences in data sources and methods, especially for forest carbon sink measurements, ranging from 0.020 to 0.157 Pg C·a-1. Carbon sink function depends on carbon exchange processes across plant-soil-atmosphere interfaces. The key pathways to enhance carbon sequestration in Northeast China under different temporal and spatial scales remains unclear. Improving terrestrial ecosystem quality is the key and core of carbon sequestration and sink enhancement. However, there is an urgent need to develop a multi-ecosystem collaborative carbon sequestration and sink enhancement technology system for the "dual carbon" goal. Future research needs to develop an accurate carbon sink measurement system that integrates multi-source data and multi-scale technologies to accurately assess the function and potential of carbon sink in Northeast China, focus on the multi-scale driving mechanism of carbon sink functions, develop new technical systems for coordinated enhancement of carbon sink for the Northeast terrestrial ecosystems, and carry out demonstrations of carbon sink enhancement technologies. These efforts will provide the scientific and technological supports for achieving the "carbon neutrality" goal.

Realistic nitrate concentrations diminish reproductive indicators in Skiffia lermae, an endemic species in critical endangered status.

Goodeinae is a subfamily of critically endangered fish native to central Mexico. Populations of Skiffia lermae, a species belonging to this subfamily, have significantly decreased in the past two decades. A previous study showed that S. lermae is sensitive to acute nitrate-nitrogen (NO3-N) exposure, leading to noticeable changes in both behavioral and histopathological bioindicators. The aim herein was to determine the vulnerability of S. lermae to NO3-N exposure at realistic concentrations registered in freshwater ecosystems in central Mexico where the species was historically reported. Offspring of S. lermae were chronically exposed during 60 days to concentrations of 5, 10 and 20 mg NO3-N/L, with 2 mg NO3-N/L used as the reference value (control). Survival rate, feeding behavior, aquatic surface respiration, body growth, scaled mass index, immature red blood cells, as well as histopathological changes in branchial, hepatic and gonadal tissues were evaluated. Additionally, this study analyzed water quality in freshwater ecosystems where S. lermae presently persists. The results showed decreased survival as NO3-N concentration increased, as well as increased feeding latency, aquatic surface respiration and histological damage in the gills and liver. These organs showed differential sex-dependent responses to NO3-N exposure; females were more sensitive than males. In the ovaries, a decreased density of stage III oocytes was associated with increased NO3-N concentrations. No changes were observed in body growth and number of immature red blood cells. Concentrations recorded in the three freshwater ecosystems that S. lermae inhabit were below 2 mg NO3-N/L. Together, the results could explain why the species has disappeared from more contaminated freshwater ecosystems where NO3-N levels exceed 5 mg/L. Moreover, the study warns about the risks of increasing NO3-N concentrations in the current sites where the species lives.

Does the electric vehicle promotion policy drive Thailand's passenger transport towards environmental sustainability?

Electric vehicles (EVs) are considered an alternative to internal combustion engine vehicles (ICEVs) for promoting sustainable transport, with environmental benefits depending on many local factors. This study performed a comprehensive life cycle assessment of passenger transport in major urban areas of Thailand, encompassing on-road, metro trains, and inland water transport, to determine the benefits of EV deployment. The findings showed that the vehicle life cycle (manufacture, maintenance, and disposal) was a significant contributor to human health and ecosystem quality impacts when comparing across transport life cycle phases in both ICEVs and EVs. Among private vehicles, with the current electricity mix, EVs had impacts on human health and ecosystem quality comparable to small-size ICEVs. At the projected 2037 electricity mix, the EVs will have lower impacts on human health, ecosystem quality and resource scarcity in comparison with the ICEVs. In scenario analysis, when considering only on-site emissions, it was found that private EV promotion had an environmental cost by about 16–43 % lower than the business-as-usual (BAU) scenario, depending on the rate of EV adoption, while shifting to public electric buses or metro trains had a lower environmental cost by 21 % and 23 % compared to BAU, respectively. If assessing the full transport life cycle, shifting to public electric buses or metro trains had a lower environmental cost (22–23 %) than the promotion of EVs with current electricity mix (14 %). The effectiveness of environmental impact mitigation through deployment of private EVs might increase to a comparable level with public electric bus or metro train shifts when Thailand achieves the electricity mix target with 34 % of renewable energy in 2037.