Ecosystem Resources Research Articles

Variability in water quality of two meso-tidal estuaries of Odisha, East Coast of India

The increasing human population and rapid development along the east coast of India pose potential threats to coastal water quality. To assess the water quality of two tropical estuaries of Odisha, India, diurnal and seasonal variations along with the influence of differential anthropogenic impacts have been studied. From the results, it was evident, the seasonal variations in the water quality were largely influenced by anthropogenic sources at both the estuaries. Relatively lower seasonal variations in salinity were recorded in Mahanadi compared to Dhamara. Dissolved inorganic nitrogen (DIN) concentrations were found to be higher in the Dhamara estuary when compared to the Mahanadi estuary that can be attributed to decay of organic materials followed by the nitrification process. A reverse trend was recorded for dissolved inorganic phosphate (DIP), with significantly higher values recorded in Mahanadi. The partial pressure of carbon dioxide (pCO2) showed strong temporal variations in both the estuaries dominated by moderate CO2 supersaturation with respect to the atmosphere. The mean annual pCO2 was higher in the Mahanadi estuary and was largely attributed to its significant increase during the post-monsoon season. This study indicated the stronger influence of freshwater input and tidal activities compared to that of in situ biological processes in regulating the temporal variations in water quality of both the estuaries. The present study is helpful in understanding the natural state of the estuarine water and protection of ecosystems resources to fulfil the sustainable development at the regional level.

Integrating assemblage structure and habitat mapping data into the design of a multispecies reef fish survey

AbstractObjectiveSince 2010, three spatially disjunct reef fish video surveys have provided fishery‐independent data critical to the assessment and management of reef fishes in the Gulf of Mexico. Although analytical approaches have recently been developed to integrate data from these surveys into a single measure of relative abundance and size composition, a more parsimonious approach would be to integrate survey efforts under a single Gulf‐wide survey design. Accordingly, we conducted a retrospective analysis of historical video‐ and habitat‐mapping data to develop a novel stratified random sampling design for conducting surveys of natural and artificial reef habitats.MethodsWe conducted a series of classification and regression tree analyses to delineate both spatial and habitat strata, and conducted simulations to assess the performance of an optimized survey design.ResultSpatially, classification and regression tree results identified three depth strata (10–25 m, >25–50 m, >50–180 m) and three regional strata (north‐central Gulf, Big Bend, southwest Florida) in the eastern Gulf. For both natural and artificial reefs, habitat strata were delineated based on a combination of relative relief (low, medium, high) and size of the individual reef feature, although reef scale differed markedly between natural (<100 m2, 100–1000 m2, >1000 m2) and artificial habitats (<25 m2, 25–100 m2, >100 m2). To optimize effort among sampling strata, effort was allocated proportionally based on a combination of habitat availability and managed‐species richness for each stratum. Simulation results indicated that relative median biases were <10% and relative median absolute deviations <30% on estimates of abundance for most species examined on natural reefs under the optimal design, except Greater Amberjack Seriola dumerili. These measures of bias and imprecision were similar or higher for most species simulated using simple random and stratified random survey designs. Estimated relative median bias and relative median absolute deviations were notably higher for artificial reef surveys.ConclusionBased on these results, survey efforts were integrated as the Gulf Fishery Independent Survey of Habitat and Ecosystem Resources (G‐FISHER) in 2020.

Fine-scale spatial variation of northern shrimp and Atlantic cod across three Norwegian fjord systems and implications for management

The spatial complexity of coastal ecosystems represents a challenge for the management of inshore resources. Here we compared two large fjord systems in northern Norway that have been closed for all bottom trawling for 50 years to a fjord with continuous shrimp fishery with bottom trawls. No significant differences were found between fjords with and without commercial trawling in population density and stock composition of northern shrimp (Pandalus borealis) and their main predator, Atlantic cod (Gadus morhua). Shrimp density was instead linked with bottom depth, while shrimp size and stage composition as well as cod density were explained by seasonal effects and shrimp density. For shrimp, a large degree of the observed variation was captured by spatial correlation that could not be explained by other covariates. The results underline the complex ecology in heavily structured coastal habitats and indicate that coastal shrimp dynamics are shaped by an interplay of multiple ecological and environmental drivers, possibly in concert with local genetic adaptations. The substantial fine-scale spatial variation adds to the challenges of assessing and managing fisheries resources in these fjord ecosystems. Because shrimp are an important forage species, notably as prey for cod, there are potential management conflicts between rebuilding cod stocks and reopening closed shrimp trawling areas.

Farmers’ Perception towards Forest Ecosystem Services and Human Well-being

Bandarban hill district is one of the main hilly areas of Bangladesh which is surrounded by forests and enriched with ecological resources and biodiversity. Ecosystems sustain, generate for, regulate, and offer cultural services that are essential to human well-being. Hence, it is important to reconnoiter the current situation of forests’ ecosystem services available in the Bandarban hill district with the local farmers’ realization of the well-being they receive from those ecosystem services. Through the present study, it was investigated the available ecosystem resources in some two hilly upazilas of Bandarban district, the farmers’ perception towards those ecosystem services and human well-being and also farmers’ socioeconomic characteristics which influence their perception. To investigate these, 80 respondents were interviewed through the help of a semi structured interview schedule. The findings of the study suggested that 28 ecosystem services were identified and six out of these were showing increasing trend including crop and vegetable cultivation and other 22 were following decreased. The respondents received improve to moderate services from those 28 ecosystem services which were exhibited through their perception as 68% of them had moderate to improve perception towards ecosystem services. According to the study's findings, respondents who had higher levels of education, family income, agricultural training, residential distance from forests, and income from ecosystem services had better perceptions of ecosystem services and human well-being. Because the residents' perceptions would make them aware of the need to conserve the forest environment, policymakers should base future decisions on the findings of this study.

Boundary resource management in innovation ecosystems: The case of e-commerce

Major challenges in contemporary information systems development demand new development approaches, such as innovation ecosystems, consisting of a focal innovation platform surrounded by independent developers. The attraction of third-party developers and the amplification of generativity in extension development call for sophisticated boundary resources. As demarcation points between an innovation platform and external developers, boundary resources entail a strategic value and need to be managed carefully. However, existing research does not provide an approach for the holistic management of boundary resources from design to retirement. We apply a design science research approach consisting of two design cycles involving a literature review identifying 26 application lifecycles and the analysis of eight innovation platforms in e-commerce. We evaluated the model for boundary resource management in interviews with nine domain experts. We develop an integrated boundary resource management lifecycle as a specialization of application lifecycle management for the holistic management of boundary resources in innovation ecosystems addressing third-party developers. The boundary resource management lifecycle consists of four layers: boundary resource governance, continuous communication, technical boundary resources, and supplementary boundary resources. It decouples technical and supplementary boundary resources while emphasizing their intertwined nature for ecosystem participants. Owners of innovation platforms can instantiate the reference procedure model for attracting developers.

Strengthening food security through alternative carbohydrates in the city-state of Singapore

Strengthening food security, in places where land and natural resources are limited or no longer available, is challenging. This is especially true for the production of staple food carbohydrates. Unlike some alternative foods, such as cultured meats, producing food carbohydrates using conventional agri-food approaches requires many natural resources, which are not available in some regions such as Singapore. Therefore, we must develop new, sustainable methods to enhance the quantity and nutritional quality of foods rich in carbohydrates. In this article, we review current developments in food security in the city-state of Singapore and emphasize the essential role of food carbohydrates in the food security plan. We discuss technology developments (i.e., indoor vertical farming, urban farming) used to enhance crop quality and production. We also make a few recommendations such as exploring underutilized and unconventional crops that are resilient and nutrient-dense, identifying hidden resources in local ecosystems (i.e., revalorizing agri-food processing by-products), and producing alternative carbohydrates (i.e., microbial and synthetic carbohydrates). Experience and approaches developed in Singapore provide an example to other regions and may inspire creativity in securing food availability.

Assessing Environmental Sustainability Based on the Three-Dimensional Emergy Ecological Footprint (3D EEF) Model: A Case Study of Gansu Province, China

Quantifying the supply and demand relationship between human social consumption and natural ecosystem resources is an effective way to assess the sustainability of ecosystem services. This paper introduces the concepts of footprint size (EFsize) and depth (EFdepth) to emergy analysis to establish a three-dimensional emergy ecological footprint (3D EEF) model and evaluates the environmental sustainability development of Gansu Province from 2001 to 2020. The results show that the minimum value of the 3D emergy ecological footprint (EEF3D) of Gansu Province was 5.98 × 107 hm2 and that the maximum value was 1.41 × 108 hm2. The EEFdepth was slightly more than one in 2015 and 2016, and the ecological resources were in deficit. However, the ecological service system from 2001 to 2020 was almost in a sustainable state. The region’s emergy carrying capacity (ECC) and emergy ecological footprint (EEF) from 2021 to 2030 are predicted using the ARIMA and GM (1, 1) models. The projections show that the ECC and EEF will increase year by year from 2021 to 2030. In the short term, the flow of natural capital can satisfy the development requirements. Finally, policy recommendations are provided for the ecological sustainability of the region.

Study of Hard Coral Community Structure and Natural Recruitment on Rote Island in the Sawu Sea Marine National Park (TNP)

Rote Island and its surroundings are included in the Savu Sea Marine National Park (TNP) area and are administratively included in the Rote Ndao Regency, East Nusa Tenggara (NTT) Province. The waters of the area have high potential for coral reef ecosystem resources and are an important for the marine biota. But when the condition is under pressure due to anthropogenic and natural influences. Therefore it is necessary to carry out routine observations related to the condition of the community structure and its potenstial natural recruitment. Observations were made on 26-28 September 2021 at 12 observation stations. The observation method used was the belt transect method with 3 repetitions (20 m) with an area of 60 m2. Data collection using SCUBA equipment at a depth of 5-7 m on the reef flat. The results of the study found a total of 37 hard coral genera and the highest species richness was in Daiama 2 (30 genera) and the lowest was in Oelua and metina (13 genera). The dominant hard coral genera found were the Porites genera. Furthermore, the potential for natural recruitment of hard coral tillers reaches 21%. The highest potential for natural recovery is at Sotimori 1 (station 3) and the lowest at Boni (station 12). In general, the hard coral community structure at the observation site is in a stable condition with good natural recruitment potential.

Leaf water δ18O, δ2H and d‐excess isoscapes for Australia using region‐specific plant parameters and non‐equilibrium vapour

AbstractOxygen (δ18O) and hydrogen (δ2H) isotope ratios, and their relationship to one another (d‐excess) are altered as water travels from the atmosphere to the land surface, into soils and plants and back to the atmosphere. Plants return water to the atmosphere through transpiration (evaporation through the stomata), which causes isotopic fractionation concentrating the heavier isotopes (18O and 2H) in the water that remains behind in the leaves. The degree of isotopic fractionation during transpiration is controlled largely by climate, and as a result can be predicted using process‐based models and climate data. The modelled transpirational isotopic fractionation can be applied to plant source water isotopic values to predict leaf water isotope ratios and generate maps of isotopic composition, or isoscapes. This approach of mechanistic modelling has been well demonstrated in the first generation of global leaf water isoscapes (PLoS One, 3(6), e2447, 2008). However, use of leaf water isoscapes in fields such as hydrology, ecology, and forensics requires a new generation of updated region‐specific isoscapes. Here, we generate leaf water isoscapes of δ18O, δ2H and d‐excess for Australia, the driest vegetated continent on Earth, where leaf water represents a critical water resource for ecosystems. These isoscapes represent an improvement over previous global isoscapes due to their higher resolution, region‐specific, empirically derived plant parameters, and non‐equilibrium corrections for water vapour isotopic composition. The new isoscapes for leaf water are evaluated relative to observed isotope ratios of leaf cellulose and cherry juice. The model predictions for annual average leaf water isotope ratios showed strong correlations with these plant tissues that integrate over time. Moreover, inclusion of region‐specific leaf temperature estimates and non‐equilibirum vapour corrections improved prediction accuracy. Regionally based isoscapes provide improved characterisations of average leaf water isotope ratios needed to support research in hydrology, plant ecophysiology, atmospheric science, ecology, and geographic provenancing of biological materials.

Forest Carbon Sequestration Potential in China under Different SSP-RCP Scenarios

The estimation of forest carbon sequestration and its economic value as a carbon sink are important elements of global carbon cycle research. In this study, based on the predicted forestland changes under the future shared socioeconomic pathways SSP1-RCP2.6, SSP2-RCP4.5, and SSP5-RCP8.5, the growth equations of different tree species were fitted using forest inventory data, and the biomass conversion factor continuum function method was used to estimate forest vegetation carbon fixation at the national scale. The carbon sink potential of the forest ecosystems in 2020–2100 was estimated under the three scenarios. Under the three social scenarios, the fixed amount of forest carbon in China exhibits a significant upward trend. Forest area increases the most, and carbon sequestration increases the most rapidly under SSP1-RCP2.6. The carbon sequestration level in Southwest China is higher than in other parts of the country, and those in Northwest and East China are lower than the national average. In order to continuously improve the carbon sequestration capacity of terrestrial ecosystem resources in China, the following actions are recommended: strengthen the protection projects of natural forests in various regions, improve the level of forest management, and gradually achieve the goal of carbon neutrality in China.

Economic and environmental benefits by means of recycling processes grounded in the CE: Case studies in the metal mechanical sector

Industrial and economic growth activities induce an increase in the generation and emission of large amounts of polluting waste to the environment. However, the scarcity of natural resources in ecosystems denotes the importance of the practical application of Circular Economy (CE) at the micro level. This research aims to evaluate the environmental and economic advantages of adopting waste recycling and reuse processes based on the CE in four industrial companies in the metal-mechanical sector. Multiple cases studies were conducted, supported by direct observations of the production processes, in addition to document examination and interviews. In the data analysis, the companies' environmental and economic gains were calculated and compared. It was concluded that the implementation of closed-loop recycling by companies in the metal-mechanic sector is an important strategy to promote CE at the micro-enterprise level. In addition to generating a consistent financial return, it resulted in the reduction of environmental impacts in the abiotic compartment (contributing to the control of global warming and flora contamination); in biotic compartment (correct disposal of wastes does not affect terrestrial living beings); in water, (the disposal of industrial waste in water bodies); and elimination of emission of any nature into the air. Despite the evidence of economic gains and the reduction of the environmental impact, environmental gains were more significant at global levels. It is expected that these findings can encourage industry managers and researchers to implement closed-loop recycling at the micro level, in addition to making its CE actions transparent to the market and government, contributing to their competitive advantage.

A new Carboniferous edaphosaurid and the origin of herbivory in mammal forerunners

Herbivory evolved independently in several tetrapod lineages during the Late Carboniferous and became more widespread throughout the Permian Period, eventually leading to the basic structure of modern terrestrial ecosystems. Here we report a new taxon of edaphosaurid synapsid based on two fossils recovered from the Moscovian-age cannel coal of Linton, Ohio, which we interpret as an omnivore–low-fibre herbivore. Melanedaphodon hovaneci gen. et sp. nov. provides the earliest record of an edaphosaurid to date and is one of the oldest known synapsids. Using high-resolution X-ray micro-computed tomography, we provide a comprehensive description of the new taxon that reveals similarities between Late Carboniferous and early Permian (Cisuralian) members of Edaphosauridae. The presence of large bulbous, cusped, marginal teeth alongside a moderately-developed palatal battery, distinguishes Melanedaphodon from all other known species of Edaphosauridae and suggests adaptations for processing tough plant material already appeared among the earliest synapsids. Furthermore, we propose that durophagy may have provided an early pathway to exploit plant resources in terrestrial ecosystems.

Changes in the feeding ecology of an opportunistic predator inhabiting urban environments in response to COVID-19 lockdown.

Urban-dwelling species present feeding and behavioural innovation that enable them to adjust to anthropogenic food subsidies available in cities. In 2020, the SARS-CoV-2 virus outbreak resulted in unprecedented reduction in the human activity worldwide associated with the human lockdown. This situation opened an excellent opportunity to investigate the capability of urban wildlife to cope with this anthropopause event. Here, we investigated the effects of the COVID-19 lockdown on the feeding strategies of the urban yellow-legged gull (Larus michahellis) population inhabiting the highly dense city of Barcelona (NE Spain). We compared the diet of chicks (through stomach content and stable isotope analyses) sampled randomly around the city of Barcelona before (2018 and 2019), during (2020) and after (2021) the COVID-19 lockdown. The results revealed that the anthropopause associated with the lockdown had an effect on the diet of this urban-dwelling predator. The diversity of prey consumed during the lockdown was lower, and consumption of urban birds (pigeons and parakeets) and marine prey (fishery discards and natural prey) decreased during the year of lockdown. Although it was not analysed, these diet changes probably were associated with variations in the availability of these resources due to the decrease in human activity during the lockdown. These results demonstrate the trophic flexibility of urban-dwelling species to cope with the changes in the availability of human-related anthropogenic resources in urban marine ecosystems.

Distribution of Marine debris in Coral Reef Ecosystems on Mules Island, Sawu Marine National Park

Mules Island and its surroundings are included in the Savu Sea National Park (TNP) area and administratively included in the Manggarai Regency, East Nusa Tenggara Province (NTT). The waters of the area have a high potential for coral reef ecosystem resources and are important support for the marine life. However, the current condition of anthropogenic pressure continues to increase due to an increase in the number of people living on the coast and small islands. One of the pressures that are currently a big issue is the existence of marine debris, where studies related to its impact and distribution on coral reef ecosystems are still very few. The purpose of this study was to determine the distribution and types of marine debris in the coral reef ecosystem on Nucamolas Island and its surroundings. Observations were made on 1-3 November 2021 at 12 stations. The research method used is the belt transect method with an area of 500 m2. Data collection was assisted by SCUBA diving equipment at a depth of 5-7 m on the coral reef flat. The results of this study found that the dominant marine debris in the coral reef ecosystem was organic waste (64.3%) and a group of macro debris (71,4%). Based on the type, the dominant species found were logs (37%), which physically damaged the coral, especially when currents and waves were moving. The distribution of marine debris at the study site was only found at 8 stations while the other 4 were not found.

Seasonal precipitation regulates magnitude and direction of the effect of nitrogen addition on net ecosystem CO2 exchange in saline-alkaline grassland of northern China

Increased nitrogen (N) deposition and altered precipitation regimes have profound effects on carbon (C) flux in semi-arid grasslands. However, the interactive effects between N enrichment and precipitation alterations (both increasing and decreasing) on ecosystem CO2 fluxes and ecosystem resource use efficiency (water use efficiency (WUE) and carbon use efficiency (CUE)) remain unclear, particularly in saline-alkaline grasslands. A four-year (2018–2021) field manipulation experiment was conducted to investigate N enrichment and precipitation alterations (decreased and increased by 50 % of ambient precipitation) and their interactions on ecosystem CO2 fluxes (gross- ecosystem productivity (GEP), ecosystem respiration (ER), and net ecosystem CO2 exchange (NEE)), as well as their underlying regulatory mechanisms under severe salinity stress in northern China. Our results showed that N addition and precipitation alteration alone did not significantly affect the GEP, ER and NEE. While the interaction of N addition and increased precipitation over the four years significantly improved the mean GEP and NEE by 24.9 % and 15.9 %, respectively. The interactive effects of N addition and increased precipitation treatment significantly stimulated the mean value of WUE by 39.1 % compared with control, but had no significant effects on CUE over the four years. Based on the four-year experiment, the magnitude and direction of the effects of N addition on the NEE were related to seasonal precipitation. Nitrogen addition increased the NEE under increased precipitation and decreased it during extreme drought. Soil salinization (pH and base cations) could directly or indirectly affect GEP and NEE via plants productivity, plant communities, as well as ecosystem resource use efficiency (WUE and CUE) based on structural equation model. Our results address lacking investigations of ecosystem C flux in saline-alkaline grasslands, and highlight that precipitation regulates the magnitude and direction of N addition on NEE in saline-alkaline grasslands.

Investments in small retention as a factor influencing land-use changes. A case study of Poland

Building permit decisions are one of the most important elements of the investment process in Poland. It should be noted that water reservoirs influence the diversification of landscapes by increasing their attractiveness in both urban and rural areas. The article aimed to verify the relationship between the changes in land-use development and investments related to small retention. Another goal was classifying objects for which building permits have been obtained and registered. Changes in land-use development associated with the introduction of ponds, which blend in with the landscape, are desirable from the perspective of retaining water resources in urban and rural ecosystems. The research methodology was based on spatial data and included statistical analyses in three regions: Mazowieckie, Lodzkie and Swietokrzyskie. Studies carried out in these regions showed a spatial correlation associated with investments in small retention. The research used methods of the global I Moran statistic and local Moran statistics. The data used in the study came from the Register of Applications, Decisions and Notifications, made available by the Main Office of Construction Site. The research indicates clusters of investments in small retention in analysed regions. The majority of investors are residents who invest in earth ponds. The study shows that investment in small retention is connected with ecosystem services.

Seasonal Changes in the Biochemical Composition of Dominant Macroalgal Species along the Egyptian Red Sea Shore

Macroalgae are significant biological resources in coastal marine ecosystems. Seasonality influences macroalgae biochemical characteristics, which consequentially affect their ecological and economic values. Here, macroalgae were surveyed from summer 2017 to spring 2018 at three sites at 7 km (south) from El Qusier, 52 km (north) from Marsa Alam and 70 km (south) from Safaga along the Red Sea coast, Egypt. Across all the macroalgae collected, Caulerpa prolifera (green macroalgae), Acanthophora spicifera (red macroalgae) and Cystoseira myrica, Cystoseira trinodis and Turbinaria ornata (brown macroalgae) were the most dominant macroalgal species. These macroalgae were identified at morphological and molecular (18s rRNA) levels. Then, the seasonal variations in macroalgal minerals and biochemical composition were quantified to determine the apt period for harvesting based on the nutritional requirements for commercial utilizations. The chemical composition of macroalgae proved the species and seasonal variation. For instance, minerals were more accumulated in macroalgae C. prolifera, A. spicifera and T. ornata in the winter season, but they were accumulated in both C. myrica and C. trinodis in the summer season. Total sugars, amino acids, fatty acids and phenolic contents were higher in the summer season. Accordingly, macroalgae collected during the summer can be used as food and animal feed. Overall, we suggest the harvesting of macroalgae for different nutrients and metabolites in the respective seasons.

Determination of Exploitable Coefficient of Coral Island Freshwater Lens Considering the Integrated Effects of Lens Growth and Contraction

Groundwater on small coral islands (so-called freshwater lens) is an important water resource for residents and local ecosystems. However, an overexploitation of it may induce a contamination by saltwater. In this paper, we strive to determine the exploitable coefficient of the freshwater lens considering the integrated effects of lens growth and contraction and examine the impacts of well layout schemes on the evolution of the freshwater lens. For this purpose, a numerical model is setup to simulate the saltwater upconing and recovery process under pumping conditions during different evolution stages. Our results show that long-term and higher intensity pumping activities are suggested to be conducted at the latter stage of the lens evolution. Meanwhile, the seasonal contraction of the freshwater lens caused by the seasonal variation in rainfall is characterized by a quicker response of center thickness than maximum thickness of the lens, which further impacts the pumping intensity. The results also indicate that the exploitable coefficient (ρ) of the freshwater lens in small coral island is generally smaller than that in inland areas, ranging from 0.09 to 0.37 under different well layout schemes. Additionally, it is also affected by the uncertainty of hydrogeological parameters. Finally, a safe exploitable coefficient is proposed under the most unfavorable parameter combination for the studied island. The study has important implications for the protection and sustainable exploitation of subsurface freshwater resources on island.

Structure of payments for the use of resources and services of aquatic ecosystems

The importance of developing and optimizing the structure of a modern payment system, which will facilitate not only the accumulation of these funds in the budget, but also to make relevant management decisionson their allocation for conservation measures and restoration of lost aquatic ecosystem functions was demonstrated. The methodological and theoretical basis of the study is the key concepts of modern economic theory, economics of environmental management and sustainable development, international ecosystem ecosystem accounting, institutional and neo-institutional theories related to the problem of scientific substantiation of payments for the use of resources and services of aquatic ecosystems. The key elements of the structure of payments for the use of water resources in Ukraine (rent for special water use, environmental tax for discharges of pollutants into water bodies, rent for water bodies, fines) are studied and analytical evaluation of these taxes were studied and performed their analytical evaluation. The main factors of low efficiency of payments for the use of aquatic ecosystem resources are identified. It is proposed scientific concepts to optimize the structure of payments for the use of resources and services of aquatic ecosystems taking into account the best models of international experience. Attention was focused on the necceserity of the creation in Ukraine a special extra-budgetary National Environmental Fund of Water Resources in the form of a legal entity, similar to the National Fund for Environmental Protection and Water Management in Poland, with the aim of accumulating payments for water ecosystem services and introducing tools to stimulate and support water protection measures. Perspectives for further research on this issue, in particular, with regard to the formation of a comprehensive strategic ecosystem approach to the introduction of payments for the use of resources and services of aquatic ecosystems, development of modern methodological approaches to assessing the services of aquatic ecosystems and formation of an optimal structure of payments for the use of water resources, taking into account their functional characteristics were identified.

Characteristics of Soil Carbon, Nitrogen, Phosphorus, and Ecological Stoichiometry in Vegetable Fields and Orchard in the Coastal Area of Fuzhou

The soil ecological stoichiometric characteristics of different agricultural land use types have a certain indicator function for characterizing the level of soil nutrient supply and are of great significance to the management of nutrient resources in farmland ecosystems. In order to reveal the soil carbon (C), nitrogen (N), and phosphorus (P) contents and their ecological stoichiometric characteristics in different vegetable fields and orchard agricultural land use types, this study took vegetable fields (taro field and jicama field) and orchards (citrus tree orchard, watermelon field, and pear tree orchard) as the research objects in the coastal area of Fuzhou City. The contents of soil C, N, and P and their ecological stoichiometric characteristics in different vegetable fields and orchard agricultural land uses were measured and analyzed. The soil C and N contents were in the order of orchard>vegetable field (P<0.05). The C content in the citrus tree orchard was the highest (4.44 g·kg-1), and the N content in the watermelon field was the highest (1.46 g·kg-1). The soil P content was vegetable field>orchard (P<0.05), and the jicama field had the highest P content (0.19 g·kg-1). The soil carbon and nitrogen ratio (C/N), carbon and phosphorus ratio (C/P), and nitrogen and phosphorus ratio (N/P) were orchard>vegetable field (P<0.05). Among them, the citrus tree orchard had the highest C/N (7.40) and C/P (61.43), and the watermelon field had the highest N/P (10.27). Soil N content was significantly and negatively correlated with bulk density and conductivity (r=-0.49, r=-0.28, P<0.05), and there was a significant and positive correlation with soil water content (r=0.61, P<0.05). C/P and C/N were significantly and positively correlated with SOM (r=0.71, r=0.64, P<0.01). In the process of crop planting and management in the coastal area of Fuzhou City, it is necessary to reasonably add nitrogen fertilizer to compensate for the N limitation, and slow-release nitrogen fertilizer is better for promoting the sustainable supply of nitrogen nutrients in the growth and development of crops.