Changes in the land-use landscape pattern and ecological network of Xuzhou planning area

Ongoing rapid urbanization has triggered significant changes in land use, rendering landscape patterns adversely impacted and certain habitat patches degraded. Ecological networks have consequently contracted overall. As such, an investigation into how land-use landscape patterns and ecological networks change over time and space is of major significance for ecological restoration and regional sustainability. Taking Xuzhou Planning Area as a case study, we examined spatiotemporal changes and features of the landscape pattern by employing the land-use change degree, the land-use transition matrix, and quantified landscape pattern indices. An ecological network analysis, which studies the changes in network connectivity and robustness, as well as their causes and contributors, was undertaken to probe into the features and trends of spatiotemporal changes in the land-use landscape pattern and ecological network amid expeditious urbanization. Analysis results unveiled the following: (1) From 1985 to 2020, there was a decline in the area of farmland, forest, and grassland, accompanied by an increase in land for construction, water bodies, and unused land. The southwestern research area witnessed farmland substantially give way to land for construction for this period, and the most dramatic change in land use occurred between 2000 and 2010. (2) The area of dominant patches in the research area shrank, along with more fragmented, complex landscapes. The land for construction was emerging as the dominant landscape by area, whereas patches of farmland, forest, grassland, and water bodies became less connected. (3) The ecological network was densely linked in the northeast, with sparser connections in the southwest. Spatial shrinkage was observed in the research area's southwestern and central ecological corridors. Overall, the number of ecological sources and corridors rose and subsequently dropped before a rebound. (4) The ecological network grew more connected and robust from 1985 through 1990, as portions of farmland were converted into water bodies, which led to an increase in ecological sources. Given a reduction in ecological sources and corridors in the southwestern and central regions between 1990 and 2010, network connectivity and robustness declined, which was reversed from 2010 onward with the addition of two ecological sources-Pan'an Lake and Dugong Lake. With an optimal ecological network in 1990, however, it deteriorated significantly by 2010. The research area saw the minimum value of its network connectivity indices of network stability index (α), evenness index (β), and connectivity index (γ), in 2010, when its ecological network was highly fragmented and vulnerable, attributing to a strong contrast between the maximal connected subgraph's relative size and connectivity robustness. The research findings can lay scientific groundwork for addressing ecological issues, restoring landscape patterns, and developing ecological networks amid urbanization.

Spatiotemporal dynamics of wetlands and their future multi-scenario simulation in the Yellow River Delta, China

Wetlands, known as the "kidney of the earth", are an important component of global ecosystems. However, they have been changed under multiple stresses in recent decades, which is especially true in the Yellow River Delta. This study examined the spatiotemporal change characteristics of wetlands in the Yellow River Delta from 1980 to 2020 and predicted detailed wetland changes from 2020 to 2030 with the patch-generating land use simulation (PLUS) model under four scenarios, namely, the natural development scenario (NDS), the farmland protection scenario (FPS), the wetland protection scenario (WPS) and the harmonious development scenario (HDS). The results showed that wetlands increased 709.29 km2 from 1980 to 2020 overall, and the wetland types in the Yellow River Delta changed divergently. Over the past four decades, the tidal flats have decreased, whereas the reservoirs and ponds have increased. The gravity center movement of wetlands differed among the wetland types, with artificial wetlands moving to the northwest and natural wetlands moving to the south. The movement distance of the gravity center demonstrated apparent phase characteristics, and an abrupt change occurred from 2005 to 2010. The PLUS model was satisfactory, with an overall accuracy (OA) value greater than 83.48 % and an figure of merit (FOM) value greater than 0.1164. From 2020 to 2030, paddy fields and tidal flats decreased, whereas natural water, marshes and reservoirs and ponds increased under the four scenarios. The WPS was a relatively ideal scenario for wetlands, and the HDS was an alternative scenario for wetland restoration and food production. In the future, more attention should be paid to restoring natural wetlands to prevent further degradation in the Yellow River Delta. This study provides insights into new understandings of historical and future changes in wetlands and may have implications for wetland ecosystem protection and sustainable development.

Analysis of spatial-temporal patterns and driving mechanisms of land desertification in China

Desertification is a major manifestation of land degradation in China. The monitoring and assessment of land desertification in China and the analysis of its driving mechanisms are crucial to the realization of the aspiration of "net zero land degradation" proposed by the United Nations Convention to Combat Desertification (UNCCD). An improved Mediterranean Desertification and Land Use (MEDALUS) model was applied to assess the multiyear spatial distribution of land desertification sensitivity across China in 2010, 2015, and 2020. A Principal Component Analysis (PCA) was used to evaluate the internal stability of the model. In addition, a Geographical Detector method was used to examine the driving mechanisms of desertification sensitivity in China. The results showed that extremely sensitive desertification areas were primarily concentrated within the Northwest Desert and Desertification Region, northern segment of the Qinghai-Tibet Plateau desert and desertification region, and western sector of the Inner Mongolia-Daxinganling Desert and Desertification Region. In addition, the proportion of land area showing an overall reduction in sensitivity (17.07 %) exceeded that showing an increase (16.56 %). This indicates an overall diminishing trend in sensitivity to land desertification across China. Land use intensity (LUI), drought resistance (DR), erosion protection (EP), and aridity index (AI) are consistently the most important drivers. From 2015 to 2020, the LUI emerged as the principal catalyst behind the transformation of land desertification sensitivity in China. Hence, emphasizing well-planned land use is vital for ensuring harmony between land utilization and ecological capacity. This study establishes a scientific basis for China's land desertification control strategy and serves as a quantitative analysis reference for the driving mechanisms.

Changes in the community structure of stony corals in the southern Mexican Caribbean

The Mexican Caribbean coral reef ecosystem has endured the effects of global and regional stressors and, recently, the massive arrivals of the free-living, floating brown algae Sargassum spp. This study aimed to evaluate spatiotemporal changes in the stony coral community structure in the southern Mexican Caribbean by a temporal comparison of live coral cover and colony density using a data set collected in 2008-2009 and a recent survey in 2021 within a Protected Natural Area. A multivariate analysis approach was used to reveal spatiotemporal changes in coral cover and colony densities. Coral cover ranged from 6.9 to 8.9% in 2008-2009 to 6.5% in 2021, the lowest values recorded for the area. Coral colony density ranged from 0.68 to 0.78 colonies m-1 in 2008-2009 to 0.68 colonies m-1 in 2021. The present results appear to represent subtle changes during the last decade.

Spatiotemporal changes in summer days (SU25) in China from 1961 to 2017 and associated circulation factors

Understanding the spatiotemporal variations in climate extremes indices, as well as the influencing factors, is critical to the scientific response to climate change. The temporal and spatial variations of SU25 (annual count of days when daily maximum temperature > 25 °C) were discussed in this study, based on daily maximum temperature data from 2398 meteorological stations in China from 1961 to 2017. The contributions of associated large-scale circulation factors to SU25 were quantitatively assessed by using the geographical detector method (GMD). The overall spatial distribution of SU25 was marked by a considerable increase from north to south. The SU25 increased significantly over time, with the national SU25 increasing at a rate of 2.5 days/decade. The Tibet Plateau (TP) had the slowest growth rate, with an average increase rate of 1.4 days/decade. The Hurst values of SU25 in all the subregions were generally high, indicating that most stations of SU25 would continue to increase in the future. Except for TP, the tipping years of other subregions were concentrated in the 1990s, and SU25 increased after the years. Among the large-scale circulation factors affecting SU25 in each subregion, Atlantic Multidecadal Oscillation (AMO) played a major role in SU25 variability. As a whole, the result of the pairwise interaction of each circulation factor was mainly nonlinear enhancement. The joint contributions of multiple factors to SU25 were larger than the contribution of each individual factor.

Spatial and temporal variations of vegetation cover and its influencing factors in Shandong Province based on GEE

Economic development has rapidly progressed since the implementation of reform and opening up policies, posing significant challenges to sustainable development, especially to vegetation, which plays a crucial role in maintaining ecosystem service functions and promoting green low-carbon transformations. In this study, we estimated the fractional vegetation cover (FVC) in Shandong Province from 2000 to 2020 using the Google Earth Engine (GEE) platform. The spatial and temporal changes in FVC were analyzed using gravity center migration analysis, trend analysis, and geographic detector, and the vegetation changes of different land use types were analyzed to reveal the internal driving mechanism of FVC changes. Our results indicate that vegetation cover in Shandong Province was in good condition during the period 2000 to 2020. The high vegetation cover classes dominated, and overall changes were relatively small, with the center of gravity of vegetation cover generally shifting towards the southwest. Land use type, soil type, population density, and GDP factors had the most significant impact on vegetation cover change in Shandong Province. The interaction of these factors enhanced the effect on vegetation cover change, with land use type and soil type having the highest degree of influence. The observational results of this study can provide data support for the policy makers to formulate new ecological restoration strategies, and the findings would help facilitate the sustainability management of regional ecosystem and natural resource planning.

Dynamic spatiotemporal change of net anthropogenic phosphorus inputs and its response of water quality in the Liao river basin

The Liao river is one of the seven major rivers in China, and the process of phosphorus (P) cycling and change of water quality in this basin are influenced to a considerable extent human activities. In this work, the traditional net anthropogenic phosphorus inputs (NAPI) model was improved by considering the dynamic change of wastewater treatment capacity and P deposition (PDEP) and reclassifying the sources of phosphorus into human P consumption (PHUM), agriculture P consumption (PAGR), livestock P consumption (PANIM) and PDEP to analyze its dynamic spatio-temporal change in the Liao river basin. The results showed that the annual mean NAPI was 785.53 kg P km^-2 yr^-1 (2001-2020), the maximum value was 940.49 kg P km^-2 yr^-1 in 2009, and the minimum value was 586.04 kg P km^-2 yr^-1 in 2001. The temporal variation of NAPI presented an increasing-fluctuation-increasing trend and was basically in line with that of the water quality throughout the three stages, and the spatial distribution of NAPI gradually increased from upstream to downstream. During the two decades, PANIM was the predominant component of NAPI with a share of 64.32%. PHUM, PAGR, and PDEP accounted for 15.97%, 11.54%, and 8.17%, respectively, and the point source NAPI (NAPIP) contributed to 4.95% of NAPI. Further, the INAPI (Improved NAPI) -MR (Multiple Regression) -SWAT (Soil and Water Assessment Tool) model was developed to predict the spatial distribution of P flux under two scenarios. The results showed that the Liao river basin experienced a reduction in P flux to different degrees due to the improvement of the wastewater treatment system, which was more significant in its downstream area. Long-term water quality monitoring is encouraged to develop refined water quality models in the future.

Spatiotemporal change and prediction of land use in Manasi region based on deep learning

The Manasi region is located in an arid and semi-arid region with fragile ecology and scarce resources. The land use change prediction is important for the management and optimization of land resources. We utilized Sankey diagram, dynamic degree of land use, and landscape indices to explore the temporal and spatial variation of land use and integrated the LSTM and MLP algorithms to predict land use prediction. The MLP-LSTM prediction model retains the spatiotemporal information of land use data to the greatest extent and extracts the spatiotemporal variation characteristics of each grid through a training set. Results showed that (1) from 1990 to 2020, cropland, tree cover, water bodies, and urban areas in the Manasi region increased by 855.3465 km², 271.7136 km², 40.0104 km², and 109.2483 km², respectively, whereas grassland and bare land decreased by 677.7243 km² and 598.5945 km², respectively; (2) Kappa coefficients reflect the accuracy of the mode's predictions in terms of quantity. The Kappa coefficients of the land use data predicted by the MLP-LSTM, MLP-ANN, LR, and CA-Markov models were calculated to be 95.58%, 93.36%, 89.48%, and 85.35%, respectively. It can be found that the MLP-LSTM and MLP-ANN models obtain higher accuracy in most levels, while the CA-Markov model has the lowest accuracy. (3) The landscape indices can reflect the spatial configuration characteristics of landscape (land use types), and evaluating the prediction results of land use models using landscape indices can reflect the prediction accuracy of the models in terms of spatial features. The results indicate that the model predicted by MLP-LSTM model conforms to the development trend of land use from 1990 to 2020 in terms of spatial features. This gives a basis for the study of the Manasi region to formulate relevant land use development and rationally allocate land resources.

Spatiotemporal changes in snow depth and the influence factors in China from 1979 to 2019

Snow depth is an important parameter to characterize the characteristics of snow cover, and it is also one of the most sensitive response factors to regional climate change. However, the extent of snow depth variability and its driving mechanisms are still unknown in China. Therefore, in this study, we used the regression analysis, root-mean-square error analysis, anomalous year analysis, and correlation analysis methods to explore the spatiotemporal variation characteristics of snow depth in China from 1979 to 2019 based on the reanalysis snow depth dataset. The results show that (1) the snow distribution in China is obviously spatially heterogeneous, and the southeastern, western, and southern regions of the Qinghai-Tibet Plateau, northern Xinjiang, and northeastern China have high values of snow depth; (2) the high-value regions are also the sensitive regions for anomalous variations in snow depth in China; (3) in the past 41 years, the interannual variability of snow depth in China has shown a significantly decreasing trend, and the linear tendency of snow depth is - 0.093 cm/10 a (p < 0.01) and the snow depth in four seasons showed a decreasing trend (p < 0.05); and (4) the driving factors of snow heterogeneity are dissimilar in different regions and seasons. In temperate zones, average air temperature is the main factor affecting snow depth in cold temperature, mid temperature, and warm temperature zones; the maximum air temperature is the main factor affecting snow depth in mid temperate and warm temperate zones. Both the minimum air temperature and the average land-surface temperature are important factors affecting the snow depth in the cold temperate, mid temperate and warm temperate zones, and all passed the significance test of 0.01.

Spatiotemporal exploration of ecosystem service, urbanization, and their interactive coercing relationship in the Yellow River Basin over the past 40 years

Understanding how ecosystem services (ESs) interact with urbanization is crucial for formulating sustainable development policies. Although previous literature has paid attention to this topic, information on complex spatiotemporal interactions between ESs and urbanization remains inadequate, especially in the Yellow River Basin (YRB), a typical basin that will usher in rapid progress of ecological protection and urbanization. In this study, we constructed a framework for evaluating ecosystem service values (ESV) and urbanization by synthesizing multi-source data in the YRB from 1980 to 2018, and further revealing the interactive coercing mechanisms of ESV and urbanization. We found that the YRB has experienced rapid urbanization, with an increasing growth trend for all urbanization indicators, especially from 2000 onwards. ESV had a significant negative correlation with urbanization, showing a decreasing trend with urbanization growth before 2000, but reversed this trend after 2000 as ecological restoration projects offset the adverse effects of urbanization on ESV. Furthermore, while significant negative spatial correlations occurred between ESV and urbanization, these correlations diminished over time. The results also revealed differences in the spatial correlations between global and local scales, with three types of spatial correlations at the local scale: High-Low (high ESV and low urbanization), Low-High (low ESV and high urbanization), and Low-Low (low ESV and low urbanization). Our results contribute to understanding the interactive coercing relationship between ESV and urbanization in the YRB, particularly at the local scale, and insights into coordinating future ecological protection and urban development.

The impact of land use and land cover changes on the landscape pattern and ecosystem service value in Sanjiangyuan region of the Qinghai-Tibet Plateau

Decades of intensifying human activities have caused dramatic changes in land use and land cover (LULC) in the ecologically fragile areas of the Qinghai-Tibet Plateau, which have led to significant changes in ecosystem service value (ESV). Taking the ecologically fragile Sanjiangyuan region of the Qinghai-Tibet Plateau as the research object, we focused on understanding the impact of LULC changes on the Sanjiangyuan's landscape pattern and its corresponding ESV, which was combined with a Markov-Plus model to predict LULC changes in 2030. The results showed: (1) from 2000 to 2020, the LULC of Sanjiangyuan has changed to varying degrees, respectively. In the central and southern regions where animal husbandry is the mainstay activity, the area of grass land converted to bareland had expanded; (2) from 2000 to 2010, the total regional ESV increased sharply. However, the total amount of ESV decreased from 2010 to 2020; (3) the overall ESV in the study area was observed to be trending down and is expected to decrease by approximately 4.25 billion CNY by 2030; (4) the fragmentation and complexity of regional landscape patterns will negatively affect local ecosystem stability and biodiversity. Overall, there is a strong temporal and spatial correlation between LULC and ESV. This study will provide a reference for the local government to provide targeted and sustainable land management policies, thereby promoting the improvement of the Qinghai-Tibet Plateau regional ecology value.

Spatiotemporal distribution characteristics of PM2.5 concentration in China from 2000 to 2018 and its impact on population

PM2.5 is an important indicator reflecting changes in air quality. In recent years, affected by climate change and human activities, the problem of environmental pollution has become more and more prominent. In this study, the PM2.5 data from 2000 to 2018 obtained by satellite remote sensing inversion algorithm were selected to analyze the temporal and spatial distribution of PM2.5 in China. The results show that the areas with higher PM2.5 concentrations were mainly in the North China, the Sichuan Basin, and the Tarim Basin. The areas with a significant increase in PM2.5 were mainly in the Northeast China, while the areas with a significant decrease were mainly in the Sichuan Basin and southeastern Gansu. The change of PM2.5 in southern China was not significantly correlated with the change of population and economy, while PM2.5 in Northeast China increases with the increase of population and economy. In 2000, 2005, 2010, and 2015, the proportion of the population polluted by PM2.5 was 8.65%, 7.2%, 22.99%, and 9.75%, respectively. The year with the highest percentage (37.63%) of population when air quality reached EXCELLENT was 2015. When the PM2.5 spatial cluster number was six, it can better reflect the PM2.5 spatial distribution state. The places with large changes in PM2.5 spatial clustering were mainly in the Northeast China, Sichuan Basin, and Tarim Basin, which were also areas with large changes in PM2.5. This study provides an important reference for atmospheric environmental monitoring and protection.

Ecological risk changes and their relationship with exposed surface fraction in the karst region of southern China from 1990 to 2020

Due to anthropogenic disturbances, the karst region in southern China is vulnerable to ecological problems such as soil erosion and surface exposure. However, limited studies on variations in large-scale ecological risk (ER) and their influencing factors, particularly the coupling/decoupling relationship with an exposed surface fraction (ESF), make ER regulations and ecological restoration challenging. The present study evaluates the ER of eight typical karst provinces in Southern China from 1990 to 2020 using the technique for order preference by similarity to an ideal solution (TOPSIS) model and ecosystem services (habitat quality, water yield, carbon storage, soil conservation, and food production), and extracts the contemporaneous ESF using Landsat satellite data in Google Earth Engine (GEE). The spatiotemporal change of ER and ESF are analyzed, and their coupling/decoupling relationship and driving mechanism are explored using coupling coordination degree (CCD) and multi-scale geographically weighted regression (MGWR) models. The results show that: (1) Over the past 30 years, the ER has increased until 2010 and subsequently declined, with an increasing mean value (0.463-0.503), except in Chongqing municipality. The ESF decreased significantly (the mean value dropped from 44.7% to 38.7%), except that in Sichuan province. (2) The average CCD between ER and ESF decreased with fluctuation of -0.017, with a decoupling relationship (58.18%). The coupling area is larger than the decoupling area in the Sichuan area, while other provinces are opposite. (3) The coupling/decoupling relationship in the study area is mainly driven by terrain (elevation, slope) and socio-economic (population density, per capita GDP) factors. More attention should be paid to the role of these factors in the continuous reduction and control of ESF and ER. This study can serve as a reference for similar studies in karst regions, such as risk assessment and surface monitoring, rocky desertification control, ecological engineering layout, and territorial planning.

Evolution patterns and spatial sources of water and sediment discharge over the last 70 years in the Yellow River, China: A case study in the Ningxia Reach

The hydrology and sediment processes in large rivers play important roles in maintaining aquatic and coastal ecosystems and advancing civilization and production in human systems. Therefore, quantitatively analyzing the spatiotemporal variability and dynamics of water and sediment discharge in large rivers is essential for improving watershed management and sustainable development in the areas surrounding rivers, especially the Yellow River, which is one of the most sediment-laden rivers in the world. In this study, we analyzed the evolution patterns and spatial sources of water and sediment discharge in the Yellow River from 1951 to 2020 and determined the impacts of different factors on water and sediment discharge variations. The results showed that the annual water and sediment discharge significantly decreased (p < 0.05) over the past 70 years, with an abrupt change occurring in 1986. The first dominant periodicity of water discharge was approximately 29 years, while the first dominant periodicity of sediment discharge was approximately 28 years. In terms of the water and sediment discharge sources, the dominant factor affecting variations in water discharge was water diversion from 1951 to 2020, while the dominant factor affecting variations in sediment discharge was sediment aggradation from 1951 to 1985 and changed to tributary inflow sediment from 1986 to 2020. In addition, the water and sediment discharge changes were also affected by anthropogenic activities, such as water and sediment diversions, dams and reservoirs, and water and soil conservation measures. In particular, the water and sediment interception capabilities of the established soil and water conservation measures gradually became saturated over time. Specifically, the maximum water and sediment interception capabilities of the current soil and water conservation measures were 12.2 billion m³ and 1.9 Gt, respectively. Overall, the results of the present study can help tailor water and sediment regulation countermeasures in the future.

Learning from the past: opportunities for advancing ecological research and practice using palaeoecological data

Palaeoecology involves analysis of fossil and sub-fossil evidence preserved within sediments to understand past species distributions, habitats and ecosystems. However, while palaeoecological research is sometimes made relevant to contemporary ecology, especially to advance understanding of biogeographical theory or inform habitat-based conservation at specific sites, most ecologists do not routinely incorporate palaeoecological evidence into their work. Thus most cross-discipline links are palaeoecology → ecology rather than ecology → palaeoecology. This is likely due to lack of awareness and/or the misnomer that palaeoecology invariably relates to the "distant past" (thousands of years) rather than being applicable to the "recent past" (last ~ 100-200 years). Here, we highlight opportunities for greater integration of palaeoecology within contemporary ecological research, policy, and practice. We identify situations where palaeoecology has been, or could be, used to (1) quantify recent temporal change (e.g. population dynamics; predator-prey cycles); (2) "rewind" to a particular point in ecological time (e.g. setting restoration/rewilding targets; classifying cryptogenic species); (3) understand current ecological processes that are hard to study real-time (e.g. identifying keystone species; detecting ecological tipping points); (4) complement primary data and historical records to bridge knowledge gaps (e.g. informing reintroductions and bioindicator frameworks); (5) disentangle natural and anthropogenic processes (e.g. climate change); and (6) draw palaeoecological analogues (e.g. impacts of pests). We conclude that the possibilities for better uniting ecology and palaeoecology to form an emerging cross-boundary paradigm are as extensive as they are exciting: we urge ecologists to learn from the past and seek opportunities to extend, improve, and strengthen their work using palaeoecological data.

Quantifying ecological and health risks of ground-level O3 across China during the implementation of the "Three-year Action Plan for Cleaner Air"

After China implemented the Air Pollution Prevention and Control Action Plan (APPCAP), PM_2.5 concentrations decreased but were still higher than national standards in major areas and ozone (O₃) concentration increased unintentionally. To further decrease PM_2.5 concentrations and reduce days with severe air pollution, the government promulgated the "Three-year (2018-2020) Action Plan for Cleaner Air" (the Three-year Action Plan) in 2018. During the three-year Action Plan, a few studies reported a continuous decline in PM_2.5, but it is unclear whether O₃ and its effects also increase with the decrease of PM_2.5 like during APPCAP. In this study, for the first time, we systematically assessed changes in ground-level O₃ concentrations and related ecological and health risks during the period of the Three-year Action Plan using nationwide O₃ measurements. The national MDA8, Exceedance, and SOMO35 indicators were reduced by 3.8%, 28.5%, and 12.6%, respectively, ecological risk indicators of M12, M7, SUM06, AOT40, and W126 were reduced by 5.4%, 5.6%, 19.5%, 15.4%, and 18.6%, respectively, from 2018 to 2020. Spatially, the greatest reduction in all the indicators except MDA8 occurred in Pearl River Delta, followed by Fen Wei Plains, while Beijing-Tianjin-Hebei, Chengdu-Chongqing, and Yangtze River Delta presented relatively small reductions. Between 2018 and 2020, the production losses caused by O₃ for wheat and rice decreased by 21.4% and 17.6%, respectively. Long-term exposure to O₃ across China over 2020 was estimated to cause about 160,795 (95% CI: 81,515-312,983) for all-cause mortality, 107,128 (95% CI: 36,703-173,823) for cardiovascular mortality, and 34,444 (95% CI: 0-72,609) for respiratory mortality, indicating decreases of 9.93%, 9.86%, and 9.78%, respectively, compared to the year 2018. Taken together, our results provided the first direct evidence for China's efforts to control O₃ pollution in recent years.

Investigating the spatiotemporal changes of land use/land cover and its implications for ecosystem services between 1972 and 2015 in Yuvacık

This study aims to determine the spatiotemporal changes of land use/land cover and ecosystem services in a 12,092.1 ha of Yuvacık planning unit (PU), by focusing on carbon storage, soil loss, water production, biodiversity, and forest fire vulnerability. Stand type maps and forest management plans designed in 1972, 2004, and 2015 were used to reveal the changes over 43 years. The results pointed out obvious changes in terms of the occurrence of private and cadastral forests as new types of land use, disappearance of coppice and pure oak stands, and the transformation of 99% of open lands into residential areas. Furthermore, degraded forests decreased considerably and mixed forests rose sharply by 117.2%. The outputs were highly related to the increase by 42% (5194.9 ha) of dense forest and shifting of 2548 ha from thinner development stage to mature stages during the period. With respect to ecosystem services, carbon storage in forest ecosystems went up by 19.3 Gg over 43 years. Moreover, soil loss declined significantly from 1.1 billion tons year^-1 to 108,549 tons year^-1, and water production decreased considerably from 1.8 billion to 2.7 million m³ year^-1. According to the Shannon evenness index, there was an increase by 0.3 and 0.2 successively. Biodiversity parameters such as tree density jumped from 18 to 46 ha^-1 in thicker development classes (more than 36 cm dbh) and positive developments in biodiversity chain noticed. Afterward, Yuvacık PU was classed in 2nd class of high wildfire vulnerability due to range of fire sensitivity index (5.22-6.88).

Appraising the historical and projected spatiotemporal changes in the heat index in Bangladesh

Climate change-derived extreme heat phenomena are one of the major concerns across the globe, including Bangladesh. The appraisal of historical spatiotemporal changes and possible future changes in heat index (HI) is essential for developing heat stress mitigation strategies. However, the climate-health nexus studies in Bangladesh are very limited. This study was intended to appraise the historical and projected changes in HI in Bangladesh. The HI was computed from daily dry bulb temperature and relative humidity. The modified Mann-Kendal (MMK) test and linear regression were used to detect trends in HI for the observed period (1985-2015). The future change in HI was projected for the mid-century (2041-2070) for three Representative Concentration Pathway (RCP) scenarios, RCP 2.6, 4.5, and 8.5 using the Canadian Earth System Model Second Generation (CanESM2). The results revealed a monotonic rise in the HI and extreme caution conditions, especially in the humid summer season for most parts of Bangladesh for the observed period (1985-2015). Future projections revealed a continuous rise in HI in the forthcoming period (2041-2070). A higher and remarkable increase in the HI was projected in the northern, northeastern, and south-central regions. Among the three scenarios, the RCP 8.5 showed a higher projection of HI both in hot and humid summer compared to the other scenarios. Therefore, Bangladesh should take region-specific adaptation strategies to mitigate the impacts of HI.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s00704-021-03705-x.

Changes in the analysis of temporal community dynamics data: a 29-year literature review

BACKGROUND

Understanding how biological communities change over time is of increasing importance as Earth moves into the Anthropocene. A wide variety of methods are used for multivariate community analysis and are variously applied to research that aims to characterise temporal dynamics in community composition. Understanding these methods and how they are applied is useful for determining best practice in community ecology.

METHODOLOGY

We reviewed the ecological literature from 1990 to 2018 that used multivariate methods to address questions of temporal community dynamics. For each paper that fulfilled our search criteria, we recorded the types of multivariate analysis used to characterise temporal community dynamics in addition to the research aim, habitat type, location, taxon and the experimental design.

RESULTS

Most studies had relatively few temporal replicates; the median number was seven time points. Nearly 70% of studies applied more than one analysis method; descriptive methods such as bar graphs and ordination were the most commonly applied methods. Surprisingly, the types of analyses used were only related to the number of temporal replicates, but not to research aim or any other aspects of experimental design such as taxon, or habitat or year of study.

CONCLUSIONS

This review reveals that most studies interested in understanding community dynamics use relatively short time series meaning that several, more sophisticated, temporal analyses are not widely applicable. However, newer methods using multivariate dissimilarities are growing in popularity and many can be applied to time series of any length.

Integrating ecosystem services and landscape ecological risk into adaptive management: Insights from a western mountain-basin area, China

There is an increasing interest in introducing ecosystem services (ESs) and landscape ecological risk (LER) into environmental policies and governance. Yet, we know little about how to integrate LER into real decision-making and ESs management. Using the ESs valuation method and the models of InVEST and LER, this study analyzed the spatiotemporal changes of cropland food production, carbon storage, water yield, biodiversity index and LER of Bailongjiang watershed (BLJW), China in 1990, 2002 and 2014, and the relationship between them. We found clear spatial differences in both ESs and LER levels in BLJW during the study period. The cropland food production service kept rising, and the areas of high yield mainly distributed in the loessal regions of BLJW with intensive human population. The carbon storage, water yield and biodiversity index first decreased and then increased. The LER was higher in the areas along the valleys with low elevation and intensive human activities. The regional ecological zoning based on overlay analysis of ESs with LER is effective for providing interactive spatial knowledge for adaptive landscape management. Our results illustrate the integrative approach on linking landscape ecological risk with ecosystem services is a comprehensive and helpful methodology for both regional risk reduction and ecosystem services enhancement at landscape scale.

Forestland landscape change induced spatiotemporal dynamics of subtropical urban forest ecosystem services value in forested region of China: A case of Hangzhou city

Understanding of urban forestland both type structure and change and their effects on forest ecosystem services (ES) is important for maintaining and enhancing the quality of life as well as ensuring sustainable urban planning in cities. In Hangzhou city of Zhejiang province in Southeast China, forestland covers more than 71% of its total land area, thereby providing a high variety of ES. Many studies have focused on the effects of land use change on ES value (ESV), but these have only applied to the first-level classification of land use. So there is an urgent need for studies to measure the effects of land use change on ESV applied to the second-level classification of land use. In this present study, from a rare insight into the forestland landscape change of Hangzhou city, the spatiotemporal dynamics of urban forest ESV (UFESV) during the period of 2000-2015 are analyzed based on the combination of remote sensing and a light-use-efficiency model (CASA). The results indicate that the total value of urban forest ES increases from 9.79 × 10⁸ Yuan in 2000 to 12.31 × 10⁸ Yuan in 2015, with a net increase of 2.52 × 10⁸ Yuan in Hangzhou city, and forested land has the highest UFESV, contributing about 99.49% of the total services value, although the area of forestland decreases by 101.99 km² over the past 15 years. Carbon fixation and oxygen release and organic matter production are the two dominant service functions, accounting for 87.56% of the total on average. The construction and planning of Hangzhou's forest city has a positive impact on the value of urban forest ES during 2000-2015.

Spatiotemporal Changes in Checkpoint Molecule Expression

Immune checkpoint inhibitors (ICIs), particularly PD-1/PD-L1 blockade, have led to therapeutic breakthrough in patients with advanced malignancy, covering the lung, breast, gastrointestinal, head and neck, urinary system, lymphoma, and solid tumor harboring MSI/dMMR. In certain cancer types, the expression level of immune checkpoint molecule will be required if the immune-based approaches are considered, especially the PD-L1 expression. However, in other types, survival benefit has been proven regardless of PD-L1 expression. It raises a question of how to select patients for immune therapy and whether the expression of immune checkpoint molecules will be optimal biomarkers. Before answering this question, a comprehensive map for the expression of immune checkpoint molecules is needed. In this chapter, we describe our current knowledge on the spatiotemporal changes in the expression of checkpoint molecules. We discuss the different frequencies of expression depending on tumor types and stages, the different patterns between primary and metastatic tumors, as well as the change of expression before and after treatment. The expression of PD-L1 has been most studied, but the threshold that separate "positive" and "negative" PD-L1 expressions and the consistency of testing platform remain under debate. Better understanding on the tumor microenvironment and expression of checkpoint molecules will help to identify patients who will benefit from checkpoint blockade therapy.

Spatial and temporal uncertainty in climatic impacts on watershed systems

Evaluating the uncertainty of climatic impacts on watershed systems is critical in planning for water supplies, water allocation, and demand at multiple scales. With the increasing frequency of water crises worldwide, understanding the nature of climatic impacts along spatial and temporal dimensions is vital to the development of timely, and spatially relevant mitigation options. This study aims to quantify the nature of hydrologic uncertainties at a spatial and temporal dimension in a regional watershed system under scenarios of varying climatic uncertainties. Watershed-wide impacts of climate change under uncertain future scenarios are modeled with the Soil and Water Assessment Tool (SWAT) for the Connecticut River Watershed of northeastern USA. Changes in watershed flows are quantified for at subbasin scale. The results show that uncertainty in climate change, primarily through variability in precipitation and temperature can lead to spatial and temporal uncertainty in hydrologic processes in the watershed system. In general, the results show that uncertainty in climate can significantly impact the spatial and temporal characteristics in runoff, infiltration, evapotranspiration, and water yield of watershed systems. Strategies to enhance watershed resilience to climatic uncertainty need dynamic information on the vulnerability. Spatial and temporal strategies for adaptation to climatic change conditions could include forest cover and management practices in sensitive locations at local and regional scales.

Spatiotemporal analysis of ecological vulnerability and management in the Tarim River Basin, China

The Tarim River Basin (TRB) is an extremely arid area in China, suffering from dry climate and intense human activities, which have brought about significant changes in ecological processes and then, led to serious ecological vulnerability (EV). This study proposes an assessment framework to evaluate EV and analyze its dynamic change in the TRB during 2005-2015. An integrated method is developed with the Fuzzy Analytic Hierarchy Process (FAHP) and the Pressure-State-Response (PSR) framework, which highlights impacts of nature and anthropogenic interference on the ecology. Specific management strategies are put forward based on the spatial recognition of ecologically vulnerable areas in the TRB. The EV is divided into four vulnerability levels including Light I, Medium II, Heavy III and Very heavy IV. Results show that the average EV is at Heavy III vulnerability level in the TRB in the last 2005-2015, and there has been an increasing trend in EV, which even has come up to the Very heavy IV vulnerability level in the year 2013-2015. As a whole, the EV displays a high-to-low gradient from east to west during the study period. Heavy III and Very heavy IV vulnerability levels, distributed in the East, mainly in the mainstream areas with characterization of frequent human interferences, tend to increase persistently. In contrast, Light I vulnerability level, mainly in the west source areas, shows a significant decline after 2010. Based on the results, some suggestions targeted at different vulnerable areas were proposed to help restore ecological environments by integrating legal managements with public efforts. The proposed methodology, reflecting the nature and human interaction on the EV is of practical use for the ecological restorations in the TRB.

Spatiotemporal evaluation of the groundwater quality in Gharbiya Governorate, Egypt

Groundwater quality indicators were monitored over 6 years (2007-2012) from 55 drinking water supply wells in Gharbiya Governorate (Egypt). The prime objective was to characterize, for the first time, the governorate-wide significant and sustained trends in the concentrations of the groundwater pollutants. Quality indicators included turbidity, pH, total dissolved solid (TDS), electric conductivity (EC), Cl^-, SO₄^2-, Na⁺, total alkalinity, hardness (total, Mg, and Ca), Fe²⁺, Mn²⁺, Cu²⁺, Zn²⁺, F^-, NH₄⁺, NO₂^-, NO₃^-, PO₄^3-, dissolved oxygen (DO), and SiO₂ contents. Detection and estimation of trends and magnitude were carried out applying the non-parametric Mann-Kendall and Thiel-Sen trend statistical tests, respectively. Factor analysis was applied to identify significant sources of quality variation and their loads. Violation of groundwater quality standards clarified emergence of Mn²⁺ (46%), Fe²⁺ (35%), and NH₄⁺ (33%). Out of the 55 wells, notable upward trends (deterioration) were significant (>95% level) for TDS (89%), NO₃^- (85), PO₄^3- (75%), NH₄⁺ (65%), total alkalinity (62%), Fe²⁺ (58%), NO₂^- (47%), Mg hardness (36%), turbidity (25%), and Mn²⁺ (24%). Ranges of attenuation rates (mg/l/year) varied for TDS (24.3, -0.7), Mg hardness (3.8, -0.85), total alkalinity (1.4, -1.2), NO₃^- (0.52, -0.066), PO₄^3- (0.069, -0.064), NH₄⁺ (0.038, -0.019), Mn²⁺ (0.015, -0.044), Fe²⁺ (0.006, -0.014), and NO₂^- (0.006, -0.00003). Highest rates marked Tanta (total alkalinity and Fe²⁺), Al-Mehala Al-Kubra (TDS, Mg hardness, and NO₃^-), Kafr Al-Zayat (NH₄⁺), Zifta (Mn²⁺), Bassyun (NO₂^-), and Qutur (PO₄^3-). Precision of the trend estimate varied in goodness of fit, for TDS (86%), Mg hardness (76%), total alkalinity (73%), PO₄^3- (67.4%), NH₄⁺ (66.8%), Mn²⁺ (55%), and Fe²⁺ (49.6%), arranged in decreasing order. Two main varimax-rotated factors counted for more than 55% of the quality variance and, in particular, significant loads of salinity (TDS, EC, Cl^-, Na⁺, and SO₄^2-), followed by the alkalinity, hardness, redox potentials (Mn²⁺ and Fe²⁺), and NH₄⁺, in decreasing order were identified. The spatial-temporal variation in pollutants originated from organic matter degradation, either naturally from the aquifer peaty sediments or anthropogenic due to improper well head protection in the urban centers or from the agricultural drains in low relief areas. Considering the latest contents of indicators and their rate of increase, the time that the permissible limits would be reached can be accurately estimated and alleviative actions could be effectively set.

Spatiotemporal changes of optical signals in the somatosensory cortex of neuropathic rats after electroacupuncture stimulation

Background

Peripheral nerve injury causes physiological changes in primary afferent neurons. Neuropathic pain associated with peripheral nerve injuries may reflect changes in the excitability of the nervous system, including the spinothalamic tract. Current alternative medical research indicates that acupuncture stimulation has analgesic effects in various pain symptoms. However, activation changes in the somatosensory cortex of the brain by acupuncture stimulation remain poorly understood. The present study was conducted to monitor the changes in cortical excitability, using optical imaging with voltage-sensitive dye (VSD) in neuropathic rats after electroacupuncture (EA) stimulation.

Methods

Male Sprague–Dawley rats were divided into three groups: control (intact), sham injury, and neuropathic pain rats. Under pentobarbital anesthesia, rats were subjected to nerve injury with tight ligation and incision of the tibial and sural nerves in the left hind paw. For optical imaging, the rats were re-anesthetized with urethane, and followed by craniotomy. The exposed primary somatosensory cortex (S1) was stained with VSD for one hour. Optical signals were recorded from the S1 cortex, before and after EA stimulation on Zusanli (ST36) and Yinlingquan (SP9).

Results

After peripheral stimulation, control and sham injury rats did not show significant signal changes in the S1 cortex. However, inflamed and amplified neural activities were observed in the S1 cortex of nerve-injured rats. Furthermore, the optical signals and region of activation in the S1 cortex were reduced substantially after EA stimulation, and recovered in a time-dependent manner. The peak fluorescence intensity was significantly reduced until 90 min after EA stimulation (Pre-EA: 0.25 ± 0.04 and Post-EA 0 min: 0.01 ± 0.01), and maximum activated area was also significantly attenuated until 60 min after EA stimulation (Pre-EA: 37.2 ± 1.79 and Post-EA 0 min: 0.01 ± 0.10).

Conclusion

Our results indicate that EA stimulation has inhibitory effects on excitatory neuronal signaling in the S1 cortex, caused by noxious stimulation in neuropathic pain. These findings suggest that EA stimulation warrants further study as a potential adjuvant modulation of neuropathic pain.