Changes In Water Yield Research Articles

Spatiotemporal changes and influencing factors of ecosystem services in the Nanchang metropolitan area, China

Ecosystem services (ES) such as carbon storage (CS), soil conservation (SC), habitat quality (HQ), and water yield (WY) play a crucial role in maintaining ecological balance and supporting sustainable regional development. With increasing environmental changes, understanding the spatiotemporal dynamics of these services and their driving factors has become essential in environmental science. This study focuses on the Nanchang metropolitan area, quantifying CS, SC, HQ, and WY from 2000 to 2020. It explores the impacts of major factors, including climate, topography, and social aspects, on the spatial heterogeneity of ES. The results reveal that between 2000 and 2020, CS and HQ decreased by 0.1385×108 tons/ha and 0.0507, respectively, while SC and WY increased by 2.4754×109 tons/ha and 1.6668×1010 m3, respectively. Notable spatial heterogeneity exists in the correlation between driving factors and changes in ES. The spatial distribution of ESs is higher in mountainous regions compared to central plains. Among human factors, population (POP) and gross domestic product (GDP) predominantly influenced changes in CS and HQ, whereas climate and POP drove changes in SC. Changes in WY were primarily affected by climate and topography. These findings suggest a need to focus on key driving factors to formulate targeted land policies aimed at enhancing the ES value in the Nanchang metropolitan area.

Impact of Climate and Vegetation Dynamics on the Ecosystem Services of Subtropical Forests—A Case Study of Baishanzu National Park Area, China

Forest ecosystems, as the primary component of terrestrial ecosystems, provide essential ecosystem services (ESs) critical for sustainable human development. However, changes in climate and vegetation can alter these forest ESs. Understanding the complex relationships between regional climate, vegetation, and ESs is key to ensuring the sustainable management of forest ESs. Therefore, this study, using Baishanzu National Park as a case example, analyzed the impacts of regional climate and vegetation dynamics (vegetation coverage, forest type, and forest structure) on forest ESs, specifically water yield (WY), soil conservation (SC), net primary productivity (NPP), and habitat quality (HQ). The results indicate that from 2000 to 2020, the forest Composite Index of Ecosystem Services (CIES) in Baishanzu National Park increased. Climate and vegetation dynamics have significant effects on forest ESs. Specifically, changes in WY and SC are primarily influenced by climate change, while changes in NPP and HQ are mainly affected by changes in forest type and structure. Complex trade-offs and synergies exist among different ESs, and the driving mechanisms of climate and vegetation changes on ES variations are also complex, involving both direct and indirect effects, with significant spatial heterogeneity. This study provides important references for the sustainable management and appropriate restoration of regional forest ESs.

Climate and vegetation change impacts on future conterminous United States water yield

Future water availability is influenced by both climate and associated vegetation dynamics. This study coupled vegetation projections from a dynamic global vegetation model (MC2) with an ecohydrological model, Water Supply Stress Index (WaSSI), to predict water yield at the 8-digit Hydrologic Unit Code (HUC8) watershed level for the conterminous United States (CONUS) for the 21st century. We considered two contrasting warming scenarios (Representative Concentration Pathways 8.5 and 4.5) and accounted for simulation uncertainty by using a large ensemble of climate model outputs. The coupled model projects a decrease in water yield across much of CONUS, especially towards end-century (2080–2099) under RCP 8.5 (warmer scenario), reaching up to −30% at the regional level, relative to the 2008–2027 baseline period. Overall, the projected water yield reduction under RCP 8.5 is roughly twice as high as under RCP 4.5. Substantial changes in water yield for watersheds in the central and southeastern United States are expected by mid-century (2040–2059), reaching up to −40% (RCP 4.5) and −75% (RCP 8.5) at at the century’s end (2080–2099), relative to 2008–2027, respectively. Climate change, rather than vegetation change, strongly dominates the projected future changes in water yield, with contributions typically one order of magnitude higher. For a small number of watersheds, the effects of vegetation change can mitigate or exacerbate the effects of climate change on water yield. Our simulation results suggest a widespread increase in aridity and evaporative indices and a decrease in soil moisture, especially under RCP 8.5. Our integrated modeling results can inform policy makers and resource development planners quantitative information of future water availability.

Water yield response to forest treatment patterns in a sierra nevada watershed

Study regionSierra Nevada Study focusSnow dominated forests serve as source water supplies to much of the western United States. In recent years, these forests have experienced an increase in both drought and wildfire, which threaten critical water resources. By reducing forest density, treatments offer a promising solution to reducing fuel loads and potentially increasing surface water yield. However, the amount of fuel load reduction necessary to produce a change in water yield is not well-characterized. The objectives of the current study are to: 1) calibrate a distributed parameter, fully-integrated and physically-based hydrologic model to available watershed data and evaluate predicted hydrologic changes for a range of fuel treatment scenarios in a heavily forested experimental basin in the Sierra Nevada (Sagehen Creek basin near Truckee, California, USA), and 2) determine the extent (threshold) of forest treatments necessary to produce substantial changes, i.e. a 25% increase, in surface runoff. New hydrological insights for the regionUsing DHI’s physically-distributed code, MIKESHE, to develop the model for Sagehen Basin, twenty forest treatment scenarios with varying canopy density reductions (CDRs) and areas of treatment were simulated for a five-year period. Statistical testing showed that significant change in runoff occurred for every developed scenario at the annual scale (99% confidence interval). Surface water yield is highly correlated with precipitation patterns, however, treatments have a compounding effect over the years and the basin has a more dramatic response to higher treatment intensities. Increasing treatment CDR was more effective at increasing water yield than increasing treatment area. Results suggest that as forest managers implement fuel treatments, water yield response depends on: 1) the degree to which treatments are implemented by either area or CDR, 2) future climate variability including extended periods of drought, and 3) basin storage conditions and how this might buffer disturbance response in the basin.

Assessing watershed-scale impacts of best management practices and elevated atmospheric carbon dioxide concentrations on water yield

Changes in water yield are influenced by many intersecting biophysical elements, including climate, on-land best management practices, and landcover. Large-scale reductions in water yield may present a significant threat to water supplies globally. Many of these intersecting factors are intercorrelated and confounded, making it challenging to separate the factors' individual contributions to shaping local streamflow dynamics. Comprehensive hydrological models constructed based on a well-established understanding of biophysical processes are often employed to address these matters. However, these models rarely incorporate all relevant factors influencing local hydrological processes, due to the reliance of these models on the latest, albeit limited, state-of-the-art research. For instance, complexities inherent in watershed hydrology, which involve multilayered interactions among potentially many biophysical factors, leave the direct analysis of subtle impacts on water yields measured in-situ largely intractable. Therefore, we propose an innovative approach to assess impacts of elevated atmospheric CO2 concentrations and flow diversion terraces (FDTs) on stream discharge rates at the watershed scale. Initially, we use a comprehensive hydrological model to account for the impacts of major climatic and landuse/landcover factors on changes in field-acquired measurements of water yield. Next, we employ conventional and advanced statistical methods to decompose the residuals of model predictions to facilitate the identification of subtle influences promoted by increases in atmospheric CO2 concentrations and the application of FDTs in an agriculture-dominated watershed. Through this innovative approach, we find that FDTs contributed to a watershed-wide, net water-yield reduction of 188.0 mm (or 28.9 %) from 1992 to 2014. Ongoing increases in ambient CO2 concentrations, which are responsible for an overall reduction in a watershed-level assessment of stomatal conductance, have led to a minor increase in stream discharge rates during the same 23-year period, i.e., 0.45 mm of water yield per year, or 1.6 % overall. Streamflow reductions explicitly caused by regional warming in the area alone, on account of increased evapotranspiration, may be overestimated due to the opposing, synergistic effects on water yield associated with CO2-enrichment of the lower atmosphere and the annual application of FDTs.

Exploring future ecosystem service changes and key contributing factors from a “past-future-action” perspective: A case study of the Yellow River Basin

Understanding the impacts of climate change and human activities on ecosystem services (ESs) and taking actions to adapt to and mitigate their negative impacts are of great benefit to sustainable regional development. In this paper, we integrate the System Dynamics Model (SD), the Future Land Use Simulation (FLUS) model, the Integrated Valuation and Trade-offs of ESs (InVEST) model, and the Structural Equation Model (SEM). We select three scenarios, SSP1–1.9, SSP2–4.5, and SSP5–8.5, from the Coupled Model Intercomparison Project 6 (CMIP6) to forecast future changes under these scenarios in the Yellow River Basin (YRB) by 2030. We predict future changes in water yield (WY), carbon storage (CS), soil retention (SR), and habitat quality (HQ) in the YRB. The results show that: (1) Under the SSP1–1.9 scenario, ecological land types such as forests, grasslands, and water bodies are protected and restored to a certain extent; under the SSP2–4.5 scenario, the degree of land spatial development occupies an intermediate state among the three scenarios; and under the SSP5–8.5 scenario, there is an obvious increase in the artificialization of the watershed's land use. (2) Under scenario SSP1–1.9, there is a comprehensive approach to sustainable development that significantly improves all ESs in the watershed, while the SSP5–8.5 and SSP2–4.5 scenarios demonstrate an increase in trade-offs between WY, HQ, and CS, especially in the downstream area. (3) Anthropogenic factors having more significant impacts in the SSP5–8.5 scenario. In this paper, we not only summarize the differences in trade-offs among various ESs but also provide an in-depth analysis of the key factors affecting future ESs, providing new ideas and insights for the sustainable development of ES in the future. In summary, we propose a prioritized development pathway for the future, a reduction of trade-offs between ESs, and an improved capacity to respond to challenges.

Novel method for ecosystem services assessment and analysis of road-effect zones

To explore the cumulative ecological effects of roads in ecologically fragile areas, the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) tool was applied to assess the spatiotemporal changes in habitat quality, water yield, and soil erosion in road-effect zones of the Western Sichuan Plateau, China. Then, generalized estimating equations were formulated to analyze the impact of synergies among road attributes, climate, topography, land cover, and other factors on ecosystem service changes. The results showed that the habitat quality within the road-effect zones was mostly affected by road grade and structure, and water yield and soil erosion were attributed to the factors of road structure, rainfall, and topography. Roadbed sections had the greatest negative impact on ecosystem services, followed by bridge sections and tunnel sections. Overall, the results of this study address habitat encroachment and soil and water loss in ecologically fragile areas, contributing to knowledge on green infrastructure planning.

Study of the effects of land use change on water yield in the Qilian Mountains in western China

The Qilian Mountains serve as significant ecological security barriers in the western region of China. Their continuous and stable water supply is essential for the sustainability of the human oasis in the Hexi Corridor, as well as for the maintenance of the desert ecosystem in the north. In the past three decades, land use in this area has changed significantly because of human activities, which has had a profound impact on water yield services. Based on the Water Yield module of the InVEST model, we evaluated the area and water yield of land use during 1990–––2020, and discussed the characteristics of water yield response to changes in land use. As a result of the study, it was found that in the Qilian Mountains during the period 1990–––2020: (1) the areas of swamp, unused land, medium coverage grassland, and woodland reduced, while the areas of high coverage grassland, low coverage grassland, cultivated land, construction land, glaciers, and water area increased, and each land use type exhibited a different degree of transformation. (2) In terms of total water yield, this declined by 1.09 × 108 m3, water yield of medium coverage grasslands, unused land, and swamp decreased, while water yield of other land uses increased, however, the responses to the change in water yield as a result of the change in land use were significant. (3) The areas with decreased water yield fall mainly within the high-altitude areas of the Qinghai Lake and Qaidam river watersheds, while the low-altitude areas were characterized by an increase in water yield. This study may provide decision-makers with guidance for protecting the ecosystem of the Qilian Mountains and developing a national park in the Qilian Mountains.

Response of water yield to silvicultural treatments in a temperate forest in northern Mexico

Forest management modifies tree cover, directly influencing various ecosystem services, such as water regulation. Evapotranspiration, water interception, surface runoff, stemflow, and throughfall are among those processes that depend on tree cover. The objective of this study was to evaluate the changes in water yield, defined as the difference between precipitation and evapotranspiration, after the application of silvicultural treatments in a temperate forest ecosystem in northern Mexico. Fifteen experimental plots were established in which the following treatments were applied: intensive management (clearcutting), semi-intensive management (selection, tree cutting of 59–61% of basal area), conservative management (selection, tree cutting of 29–31% of basal area), and no treatment (control group). Incident precipitation, throughfall, stemflow, net precipitation, interception, and surface runoff were analyzed. Results show that conservative management treatments increase water yield between 2 to 3.6 mm per m-2 ha-1 of tree basal area removed. Water flow distribution, in relation to the incident precipitation, ranged from 72.3 to 91.8% for throughfall, 0.2 to 0.4% for stemflow, 72.7 to 91.8% for net precipitation, 8.19 to 27.42% for interception or evaporation, and 0.54 to 1.93% for surface runoff. The conservative management treatment was the most viable alternative for increasing water yield without compromising timber harvesting and loss of soil due to hydric erosion.

Spatiotemporal changes in future water yield and the driving factors under the carbon neutrality target in Qinghai

The carbon neutrality target has prompted China to restructure its environmental governance system, influencing regional hydrological processes and ultimately affecting future water yield. Considering land use/land cover changes (LUCC) and climate changes, this study examines the impact of China's carbon neutrality target on future water yield. By integrating Future Land Use Simulation and Coupled Model Intercomparison Project datasets, the future water yield is characterized and analyzed under three distinct scenarios: the baseline scenario, carbon neutrality target scenario, and rapid development scenario. Furthermore, the study identifies the dominant driving factors of water yield under different scenarios at both regional and sub-basin scales from 2000 to 2060. Results reveal a clear increase in future water yield with a short-term lag effect of LUCC and climate change. Precipitation emerges as the dominant driving factor of water yield in Qinghai, though its contribution will decrease while vegetation's contribution will increase. The primary driving factors differ across various sub-basins, and the result indicates that maintaining the current land-use policy in Qaidam and Hexi corridor-Alxa Basins is conducive to the improvement of future water yield, while aligning land use with carbon neutrality targets benefits water yield in the Lancang River, Qangtan, Yellow River, and Yangtze River Basins. Notably, this underscores that the pursuit of carbon neutrality goals may not uniformly benefit water yield across all sub-basins. Instead, Qinghai can rely on higher quality and more extensive vegetation to enhance future water yield. This study offers valuable insights that can contribute to the effective management of water resources at the regional level under the carbon neutrality target.

Aerodynamic effects cause higher forest evapotranspiration and water yield reductions after wildfires in tall forests.

Wildfires are increasing in frequency, intensity, and extent globally due to climate change and they can alter forest composition, structure, and function. The destruction and subsequent regrowth of young vegetation can modify the ecosystem evapotranspiration and downstream water availability. However, the response of forest recovery on hydrology is not well known with even the sign of evapotranspiration and water yield changes following forest fires being uncertain across the globe. Here, we quantify the effects of forest regrowth after catastrophic wildfires on evapotranspiration and runoff in the world's tallest angiosperm forest (Eucalyptus regnans) in Australia. We combine eddy covariance measurements including pre- and post-fire periods, mechanistic ecohydrological modeling and then extend the analysis spatially to multiple fires in eucalypt-dominated forests in south-eastern Australia by utilizing remote sensing. We find a fast recovery of evapotranspiration which reaches and exceeds pre-fire values within 2 years after the bushfire, a result confirmed by eddy covariance data, remote sensing, and modeling. Such a fast evapotranspiration recovery is likely generalizable to tall eucalypt forests in south-eastern Australia as shown by remote sensing. Once climate variability is discounted, ecohydrological modeling shows evapotranspiration rates from the recovering forest which reach peak values of +20% evapotranspiration 3 years post-fire. As a result, modeled runoff decreases substantially. Contrary to previous research, we find that the increase in modeled evapotranspiration is largely caused by the aerodynamic effects of a much shorter forest height leading to higher surface temperature, higher humidity gradients and therefore increased transpiration. However, increases in evapotranspiration as well as decreases in runoff caused by the young forest are constrained by energy and water limitations. Our result of an increase in evapotranspiration due to aerodynamic warming in a shorter forest after wildfires could occur in many parts of the world experiencing forest disturbances.

Land use/land cover change and soil property variation increased flood risk in the black soil region, China, in the last 40 years

Land use/land cover change and soil property variation driven by agricultural development substantially affect hydrological processes. Although previous studies have shown that land use/land cover change increases flood risk, how much soil property variation contributes to changes in water yield remains unclear in large-scale regions. Quantifying the water yield response to long-term land use/land cover change and soil property variation in agricultural regions is critical for flood risk control. The black soil area in China was chosen as the study area, and land use/land cover change, soil property variation, and changes in water yield during 1980–2020 were estimated. Land use/land cover change and soil property variation scenarios were established to separate the contributions of land use/land cover change and soil property variation to changes in water yield. The results showed that cultivated land and urban land expanded from 1980 to 2020. The plant available water capacity decreased by 2.10% and 7.27% in the black soil area and typical black soil area, respectively, and the water yield increased by 5.52% and 8.49% in the black soil area and typical black soil area, respectively. Land use/land cover change and soil property variation accounted for 58.64% and 36.67% of the increase in water yield in the black soil area. However, in comparison to land use/land cover change (47.40%), soil property variation (48.77%) accounted for a larger portion of the increase in water yield in the typical black soil area. Both land use/land cover change and soil property variation increased flood risk, however, the effects of soil property variation may exceed those of land use/land cover change, as determined by the spatial scale. This study can provide important information for land use planning and soil hydrological property improvements to reduce flood risk.

Impacts of Land Use and Climate Change on Ecosystem Services in Agro-pastoral Ecotone

Land use and climate change are the most important factors driving the change in ecosystem services (ESs). It is critical to understand the mechanisms behind such changes for improving ESs. However, there is still a lack of accurate understanding of change and dominant influencing factors of ESs in the agro-pastoral ecotone. This study took Naiman Banner, a typical farming pastoral ecotone in China, as the case study area. Based on the InVEST model, the revised wind erosion equation (RWEQ) and the revised universal soil loss equation (RUSLE) were used to calculate water yield, soil retention, and windbreak and sand-fixing in Naiman Banner in 2005 and 2015. Finally, the impacts of land use and climate change on these three ecosystem services were analyzed by using contribution rate formula, Pearson correlation coefficient, and geodetector methods. The results indicate that:① from 2005 to 2015, water yield and soil retention in Naiman Banner showed an overall upward trend, increasing by 22.41% and 6.74%, respectively, and windbreak and sand-fixing decreased by 66.24%. ② The change in water yield and windbreak and sand-fixing was mainly affected by climate change, and the change in soil retention was mainly affected by land use change. ③ Actual evapotranspiration change and land use change were the main factors affecting the spatial differentiation of water yield, with the explanatory powers of 94.50% and 50.05%, respectively. The main factors influencing the spatial differentiation of windbreak and sand-fixing were actual evapotranspiration change and land desertification degree, with the explanatory power of 19.84% and 16.15%, respectively. ④ The correlation of ESs in Naiman Banner was weak, and only windbreak and sand-fixing and water yield showed a weak significant synergy. Based on the results, we recommend that managers increase the proportion of grassland in sandy areas, implement closed management in pastoral areas, and introduce drip irrigation and other water-saving technologies in farmland, and ecological protection should continue to be given priority in city.

The Impacts of Land Use Changes on Water Yield and Water Conservation Services in Zhangjiakou, Beijing’s Upstream Watershed, China

The Water Conservation Functional Zone and Ecological Environmental Supporting Zone (the Capital Two Zones in China), Zhangjiakou (ZJK) City, situated in China, has played a key role in mitigating water scarcity pressure on Beijing via delivering sustainable and high-quality water yield, as well as water conservation services aimed at maintaining the ecological functions of the Capital Two Zones. However, the changing mechanism for both water yield and water conservation services instigated by the combined impacts of human activities and climate change remains poorly understood. In this study, we used the Integrated Valuation of Ecosystem Services and Trade-offs Tools (InVEST) model to analyze the changes in water yield and water conservation services, revealing the impacts of different land use scenarios. The results showed significant forest and impervious land area increment, while the water surface area decreased sharply from 1990 to 2020, with obvious urbanization expansion in ZJK during the period. Average annual water yield and water conservation from 1990 to 2020 were recorded at 48.98 mm and 2.35 mm, respectively. Precipitation emerged as the primary driver of water yield and conservation service changes, while the south of ZJK generally exhibited higher water yield and conservation service than the north of ZJK. Results also indicate that grassland had the highest water yield, with an average of 56.60 mm, followed by forest (55.66 mm) and shrub (55.07 mm). Further, the forest had the highest water conservation value (3.73 mm), followed by shrub (2.56 mm), and grassland (2.37 mm), respectively. The return of cropland to forest scenario had the most substantial decrease in water yield. Findings suggest that precipitation has a direct impact on water yield and conservation services via the amount of atmospheric water input, while land use alteration contributes to changes in regional-scale water.

Influences of Ecological Restoration Programs on Ecosystem Services in Sandy Areas, Northern China

Ecosystem services (ESs) are important for supporting human development. However, a changing climate and anthropogenic impacts are resulting in the degradation of dryland ecosystems to varying degrees. While there has been the global implementation of Ecological Restoration Programs (ERPs) to restore degraded ecosystems, there remains limited comprehensive assessment of their impacts on ESs of drylands. In this study, the sandy areas of northern China were used as the study area. The RUSLE, RWEQ, CASA, and InVEST models were used to simulate four major ESs: soil conservation (SC), sand fixation (SF), carbon sequestration (CS), and water yield (WY). The study aimed to evaluate the influences of various ERPs on major ESs. The dominant factors affecting the overall benefits provided by ESs were also identified. Since ERPs were implemented, forest areas have increased by 2.8 × 104 km2, whereas the areas of cropland, shrubland, and grassland have decreased. There were generally increasing trends in SF, SC, and CS, whereas there was a decreasing trend in WY. We then used a scenario-based simulation approach to eliminate the influence of climate variability on ESs. The results showed increasing trends in SF, SC, and CS, whereas there were minimal changes in WY. The results suggested that although ERPs can significantly increase regional ESs, unregulated expansion in vegetation can result in a water crisis and affect regional water security.

Analysis of Water Yield Changes in the Johor River Basin, Peninsular Malaysia Using Remote Sensing Satellite Imagery

Changes in land-use–land-cover (LULC) affect the water balance of a region by influencing the water yield (WY) along with variations in rainfall and evapotranspiration (ET). Remote sensing satellite imagery offers a comprehensive spatiotemporal distribution of LULC to analyse changes in WY over a large area. Hence, this study mapped and analyse successive changes in LULC and WY between 2000 and 2015 in the Johor River Basin (JRB) by specifically comparing satellite-based and in-situ-derived WY and characterising changes in WY in relation to LULC change magnitudes within watersheds. The WY was calculated using the water balance equation, which determines the WY from the equilibrium of precipitation minus ET. The precipitation and ET information were derived from the Tropical Rainfall Measuring Mission (TRMM) and moderate-resolution imaging spectroradiometer (MODIS) satellite data, respectively. The LULC maps were extracted from Landsat-Enhanced Thematic Mapper Plus (ETM+) and Landsat Operational Land Imager (OLI). The results demonstrate a good agreement between satellite-based derived quantities and in situ measurements, with an average bias of ±20.04 mm and ±43 mm for precipitation and ET, respectively. LULC changes between 2000 and 2015 indicated an increase in agriculture land other than oil palm to 11.07%, reduction in forest to 32.15%, increase in oil palm to 11.88%, and increase in urban land to 9.82%, resulting in an increase of 15.76% WY. The finding can serve as a critical initiative for satellite-based WY and LULC changes to achieve targets 6.1 and 6.2 of the United Nations Sustainable Development Goal (UNSDG) 6.

Quantifying the independent contributions of climate and land use change to ecosystem services

Ecosystem services (ESs) are critical to human welfare and play an important role in supporting sustainable social and economic development. Climate change (CLC) and land use change (LUCC) are two of the most important factors influencing ESs. However, few studies have tried to distinguish the independent contributions of CLC and LUCC to ESs. Using meteorological, soil, land use, and remote sensing data for Liaoning Province (China) from 2000 to 2020, the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model and Carnegie-Ames Stanford Approach (CASA) model were used to construct scenario simulation frameworks based on three hypothetical scenarios: 1) CLC effect only; 2) LUCC effect only; 3) a combined effect of CLC and LULC. The three scenario simulation frameworks were then used to determine the independent contributions of CLC and LUCC to net primary productivity (NPP), water yield (WY), soil retention (SR), and their temporal dynamics. Results showed that under the combined effect of CLC and LULC, NPP, WY and SR in Liaoning Province exhibited a trend of gradual increase from 2000 to 2020, increasing by 124.62 gC/m2, 30.64 mm/a and 0.63 t/km2, respectively. Under the CLC only scenario, WY and SR changed by 6.24% and 2%, respectively, exhibiting a more significant effect than under the LUCC only scenario. In contrast, NPP changed by 25.71% under the LUCC only scenario, which was more significant than under the CLC only scenario. Overall, CLC was found to be the dominant factor affecting changes in WY and SR in Liaoning Province, with independent contribution rates of 81.79%-84.02% and 73.57%-85.44%, respectively, whereas LUCC was the dominant factor affecting changes in NPP with an independent contribution rate of 86.12%-92.50%. Decreased precipitation levels and an increase in temperature were the two primary factors driving fluctuations in the independent contributions of CLC to WY and SR, while large-scale forest land area damage and rapid urbanization were the two primary factors driving fluctuations in the independent contribution of LUCC to NPP. The results of this study identify the specific effects of different climatic conditions on ESs and highlight the conflict between urbanization and ecosystem service provision, providing a theoretical foundation for improving and increasing ESs and regional sustainable development in Liaoning Province.

Spatiotemporal Changes in Water Yield Function and Its Influencing Factors in the Tibetan Plateau in the Past 20 Years

The Tibetan Plateau, known as the “Water Tower of Asia”, has made important contributions to global climate regulation and water conservation. With global climate change and water shortages, the yield and reserves of water on the Tibetan Plateau have undergone obvious changes, and its water yield function and water conservation function have gradually attracted widespread attention. The results show that the total water yield in the past 20 years is 128,403.06 billion m3, spatially reduced from southeast to northwest, and the interannual variation is large but increases slowly overall. The water yield capacity is higher in the areas of less than 3000 m and 3500~4500 m, and it is stronger with the increase in slope. The water yield capacity is extremely strong in the middle and north subtropical zone. Ecological zones with high water yield capacity are mostly covered with woodland and alpine meadows. The precipitation (P) is the dominant factor in the water yield function before actual evapotranspiration (AET) = 500 mm, and then the negative force of AET is enhanced. High altitude inhibits the positive effect of the normalized vegetation index (NDVI), and the water yield at altitudes of less than 3000 m shows an almost linear relationship with the leaf area index (LAI). When LAI > 0.2, the slower the slope, the higher the water yield and the lower the growth rate. The spatial distribution of P change and water yield change is consistent and significantly positively correlated; P and NDVI changes positively affected changes in water yield, while AET and LAI changes had the opposite effect. In summary, combined with topographic factors, this study emphasizes the influence of climate and vegetation changes on the spatiotemporal changes in water yield on the Tibetan Plateau, which can provide a theoretical basis for the assessment and prediction of water yield capacity and water conservation capacity in this area.

Analysis of water yield changes in the Yellow River basin based on the INVEST model

As one of the most important ecological environments in northern China, the productivity of the Yellow River basin as well as the conservation of water resources is of vital importance. The study of water production mechanisms in the basin is important to maintain environmental and ecological harmony.Based on the understanding of spatial analysis, this study combined with the InVEST model to conduct water yield analysis of the Yellow River basin, using the measured data of precipitation, evapotranspiration, and land use types in the Yellow River basin for the four years 2005, 2010, 2015, and 2020, respectively, to summarize the factors affecting the water yield of the basin. The conclusions show that the total water yield of the Yellow River and its basin increased by 49.7 mm from 2005 to 2020, with high water yield concentrated in the western and southwestern parts of the basin and low water yield concentrated in the northwestern part. High water yield was found in areas with high precipitation intensity in the basin; the influence of grassland was the most significant, providing nearly 62.6% of the total water yield.

Modeling wildfire effects on streamflow in the Cascade Mountains, Oregon, USA

Increasing occurrence of large and severe wildfires represents a growing threat to forested watersheds and the many ecosystem services they provide. Past research has shown that wildfires can cause substantial increases in peak flows and annual water yields, leading to potential water quality concerns and land and water management challenges. However, responses have been variable, and there have been few studies at large basin scales, leading to uncertainties about post-fire hydrologic responses. To address these uncertainties, we projected the effect of three large wildfires (>70,000 ha) on streamflow in two important forested watersheds in the Cascade Range of Oregon, US. We modeled the streamflow response using the Soil and Water Assessment Tool (SWAT) model, calibrated on data from prior to the wildfires. We modified model parameters to represent the impacts of the wildfires based on burn severity maps. Burned and unburned scenarios were compared using random forest models to identify drivers of increased annual water yields and peak flows. Post-fire annual water yield changes were controlled by burn severity, annual precipitation, area burned, aridity, and vegetation type, while post-fire peak flow changes were controlled by burn severity, area burned, aridity, soil type, and geologic province. We also found that post-fire increases in annual water yields, peak flows, and low flows were greatest at the headwater scale but were more muted at the downstream basin scale. Our work provides valuable insights into the range of potential post-fire streamflow changes at the headwater and larger basin scale, which is becoming increasingly critical for effective forest and water management decisions.