An advanced TSMK-FVC approach combined with Landsat 5/8 imagery for assessing the long-term effects of terrain and climate on vegetation growth.

Introduction: As an exceptional geographical entity, the vegetation of the Qinghai-Tibetan Plateau (QTP) exhibits high sensitivity to climate change. The Baima Snow Mountain National Nature Reserve (BNNR) is located in the south-eastern sector of the QTP, serving as a transition area from sub-tropical evergreen broadleaf forest to high-mountain vegetation. However, there has been limited exploration into predicting the temporal and spatial variability of vegetation cover using anti-interference methods to address outliers in long-term historical data. Additionally, the correlation between these variables and environmental factors in natural forests with complex terrain has rarely been analyzed. Methods: This study has developed an advanced approach based on TS (Theil-Sen slope estimator) MK (Mann-Kendall test)-FVC (fractional vegetation cover) to accurately evaluate and predict the time and spatial shifts in FVC within the BNNR, utilizing the GEE (Google Earth Engine). The satellite data utilized in this paper consisted of Landsat images spanning from 1986 to2020. By integrating TS and MK methodologies to monitor and assess the FVC trend, the Hurst index was employed to forecast FVC. Furthermore, the association between FVC and topographic factors was evaluated, the partial correlation between FVC and climatic influences was analyzed at the pixel level (30×30m). Results and discussion: Here are the results of this research: (1) Overall, the FVC of the BNNR exhibits a growth trend, with the mean FVC value increasing from 59.40% in 1986 to 68.67% in 2020. (2) The results based on the TS-MK algorithm showed that the percentage of the area of the study area with an increasing and decreasing trend was 59.03% (significant increase of 28.04%) and 22.13% (significant decrease of 6.42%), respectively. The coupling of the Hurst exponent with the Theil-Sen slope estimator suggests that the majority of regions within the BNNR are projected to sustain an upward trend in FVC in the future. (3) Overlaying the outcomes of TS-MK with the terrain factors revealed that the FVC changes were notably influenced by elevation. The partial correlation analysis between climate factors and vegetation changes indicated that temperature exerts a significant influence on vegetation cover, demonstrating a high spatial correlation.

Spatio-temporal effects of built environment on running activity based on a random forest approach in nanjing, China.

Running activity is closely related to the urban built environment in terms of mental and physical health, and this relationship can change as a result of spatio-temporal changes. Most studies, however, do not account for this and assume a linear relationship exists between the built environment and running activity. This study, therefore, collected running data spanning 2019-2022, studied spatial distribution of four-year running activity, established built environment indicators, used a random forest approach to investigate the non-linear relationship between them, and evaluated spatio-temporal changes in the relationships over time. The findings suggested that running activities are spatially clustered and the degree of clustering varies over time, and nonlinear relationships and threshold effects between the built environment and running activity can be found through the random forest algorithm and partial dependence plots. Urban park green space, greenway, and the normalized difference vegetation index had the most significant effects on running activity. The effects of population, buildings, streets, road intersections, and points of interest on running activity changed during the Coronavirus disease 2019 pandemic. In 2022, however, these effects were consistent with those during the pre-pandemic period. Our findings fill research gaps by using spatio-temporal analysis and a non-linear approach; they can also provide a reference for urban planners in building running-suitable and healthy cities.

The Allocation Change of Rural Land Consolidation Type Structure under the Influence Factors of Different Geographical and Economic Development of China.

Land consolidation structure reflects land consolidation function, and studies about its spatio-temporal change and driving mechanism can serve for regional management and control land consolidation. At present, the analysis of regional differences, time changes, and driving factors of land consolidation type structure change is relatively lacking. Based on the data of provincial acceptance projects from 2000 to 2014, this paper analyzes the spatio-temporal change of rural land consolidation type structure in China, discusses the impact of relevant policies, and identifies the socio-economic driving factors in key regions by employing correlation analysis and the PLSR (partial least squares regression) method. The results showed that from 2000 to 2014, the proportional increase of land arrangement in China was significantly correlated with the proportional decrease of land reclamation (R2 = 0.93), and the proportional decrease of land development (R2 = 0.99) showed an obvious co-evolution pattern of increase and decrease; TILC (The area of land development/The area of land arrangement) decreased from 2.14 to 0.91 in 2002-2003. Since 2003, the dominant type of land consolidation in China has gradually changed from land development to land arrangement. However, the proportion of land development in QT (Qinghai-Tibet), JY (Jin-Yu), and FGH (Fujian-Guangdong-Hainan) areas is still more than 40%; the change of land consolidation type structure was influenced by policies, social and economic factors, such as urbanization rate, fixed assets investment, industrial proportion, and population density, and the regional difference was significant: the eastern section (JZS, Jiangsu-Zhejiang-Shanghai) is the industry proportion, the central area (HHAJ, Hunan-Hubei-Anhui-Jiangxi) is grain production and fixed assets investment, the western region (NW, Northwest China) has the urbanization rate, grain production, population density, and fixed assets investment. Land consolidation structure should be configured differentially in each region based on the identification of regional function orientation and comprehensive consideration of regional resource endowment and development needs and directions to improve the efficiency of land consolidation.

[Spatial and Temporal Distribution and Source Variation of Heavy Metals in Cultivated Land Soil of Xiangzhou District Based on EBK Interpolation Prediction and GDM Model].

In order to explore the spatial and temporal changes in spatial patterns and source changes in heavy metals in Xiangzhou District, 395 and 326 soil samples were collected from cultivated soil in Xiangzhou District in November 2009 and November 2019, respectively. The contents of Cr, Pb, As, Hg, and Cd during these two years were measured. The spatial pattern and variation distribution of five types of heavy metals during these two years were obtained by using the empirical Bayesian Kriging (EBK) method. The effect (q-statistic) of 19 environmental factors and 5 types of heavy metals was calculated by using the geographical detector model (GDM), and the changes over the two years were compared. The results showed that compared with that in 2009, the heavy metal contents of Cr, Pb, Hg, and As in Xiangzhou District were decreased as a whole in 2019, whereas the Cd content increased overall. The spatial differentiation of heavy metals in the soil in Xiangzhou District in 2019 was more complicated than that in 2009. Pb, Hg, and Cd in the south and Hg in the central urban area and surrounding areas also increased. The content of each element decreased to the north and northwest. Compared with that in 2009, the explanatory power of natural factors and the distance between pollution enterprises on the single factor of the five soil heavy metal contents in 2019 decreased, and the influence on the contents under the control of single factors decreased significantly. The superposition influence of human activity factors increased, especially the distance between residential land, road, and land for pollution enterprises and environmental factors on soil heavy metal elements. These results indicated that the changes in soil heavy metal sources in 2019 tended to be complex, with structural factors as the main influencing factor. The influence of the emission of polluting enterprises on heavy metal elements decreased, whereas the influence of human activities on heavy metal content increased.

Assessment of vegetation change on the Mongolian Plateau over three decades using different remote sensing products.

As a major component of temperate steppes in the Eurasian continent, the Mongolian Plateau (MP) plays a pivotal role in the East Asian and global carbon cycles. This paper describes the use of five remote sensing indices derived from satellite data to characterize vegetation cover on MP, namely: gross primary production (GPP), net primary production (NPP), normalized difference vegetation index (NDVI), leaf area index (LAI) and fractional vegetation cover (FVC). It is found that GPP, NPP, and NDVI exhibit increasing trends, whereas LAI and FVC present decreasing trends on the MP since 1982. The different indices highlight discrepancies in the spatial pattern of vegetation growth, with the greatest increase in the southeast of MP. Only 3.4% of the total land area of MP exhibited consistent trends in the indices (0.1% degradation and 3.3% growth, P < 0.01), with the synchronous change of both LAI and NPP exhibiting higher consistency than that of raw NDVI and NPP. Understanding of the characteristics and status of vegetation change on the MP has far-reaching implications for its ecological protection management, and climate change mitigation.

Small-area spatial-temporal changes in pre-exposure prophylaxis (PrEP) use in the general population and among men who have sex with men in the United States between 2012 and 2018.

PURPOSE: Oral emtricitabine/tenofovir disoproxil fumarate was approved for use as pre-exposure prophylaxis (PrEP) by the U.S. Food and Drug Administration in 2012. We used national pharmacy data to examine trends of PrEP use in U.S. counties from 2012 to 2018. METHODS: Using multi-level small-area spatio-temporal modeling, we calculated the estimated annual percentage change (EAPC) in prevalence of PrEP use in the general population from 2012 to 2018. We also used a proxy measure for prevalence of PrEP use among men who have sex with men (MSM) to evaluate trends of use among MSM, the PrEP use-to-MSM ratio (PmR) or number of male PrEP users per 1000 MSM population. RESULTS: The prevalence of PrEP use and PmR increased (EAPC range: (+26.9%, +71.0%) and (+28.4%, +158.7%), respectively) in all counties with varying magnitude of increase. Counties of the Midwest and the upper South and upper West had the slowest increase in prevalence of PrEP use (EAPC range: (+26.9%; +52.9%)). Counties of the northern part of the South had the lowest PmR (EAPC range: (+28.4%; +76.0%)). Counties of the most populous core-based statistical areas had a relatively faster increase in population prevalence of PrEP use but slower increase in PmR. CONCLUSIONS: All counties in the U.S. have witnessed an increase in PrEP use with important geographic variabilities. Identifying areas with slow improvement in PrEP use, as well as "model counties" with the fastest pace of progress in PrEP coverage, is critical to inform local and state-level policies and program evaluation for PrEP scale up, particularly among MSM at higher risk for HIV.

The spatial and seasonal variations of bacterial community structure and influencing factors in river sediments.

Studying the composition and structure of bacterial communities in sediments helps to understand the contribution of bacteria to environmental changes and the role of feedback in response to disturbances. However, seasonal changes in bacterial communities of river sediments with different pollution levels and sources have not been clear yet. In this study, we collected sediment samples during the dry season, wet season and level season from 40 sites with various pollution sources in three inflow rivers (Fengle-Hangbu River, Nanfei River and Zhegao River) of Chaohu Lake. Bacterial community compositions were determined based on high-throughput sequencing. The 'Bioenv' in the R package 'Vegan' and redundancy analysis was used to explore the influence of environmental factors on the bacterial community in the river sediments. Results showed that a significant deviation in bacterial communities was found among seasons and rivers. In addition, seasonal dynamics had a greater impact on shaping bacterial communities than rivers with different pollution sources. A higher diversity was found in the wet season as compared to the other seasons. The bacterial diversity was negatively correlated with nutrients (OM, TN, NH4+, IP, OP and TP) and metals (Cu and Zn). Bacterial communities were more sensitive to heavy metals pressure than nutrients. We also concluded that heavy metals (Cu and Cd) were the key contributing factors in explaining variations in bacterial communities. This study provided a valuable reference for assessing ecological stress.

[Spatial-temporal distribution of vegetation net primary productivity and its driving factors from 2000 to 2015 in Shaanxi, China.] / 2000­2015å¹´é™•è¥¿æ¤è¢«å‡€åˆçº§ç”Ÿäº§åŠ›æ—¶ç©ºåˆ†å¸ƒç‰¹å¾åŠå ¶é©±åŠ¨å› ç´ .

Using MOD17A3 NPP time series data, surface cover type data, weather data, MOD16 evapotranspiration products and terrain data, the temporal and spatial variability of vegetation net primary productivity (NPP) in Shaanxi Province from 2000 to 2015 was analyzed, and its response to each influencing factor were discussed. The results showed that the NPP of Shaanxi had a significant upward trend in the past 16 years with a slope of 5.02 g C·m-2·a-1. The annual average of NPP was 344 g C·m-2·a-1 with a range from 247 to 390 g C·m-2·a-1. The NPP at 61.2% area of Shaanxi Province showed a significant increasing trend, which were mainly distributed at northern part of Shaanxi, Weibei area and western part of Qinba Mountain. There was a decrease trend of NPP for the area around Xi'an and Baoji City, accounting for only 2.5% of the whole province. During the study period, the variation of annual mean temperature and annual precipitation in Shaanxi showed no significance. The temperature showed a increase trend and the precipitation showed a decrease trend, implying a drier and warmer climate trend in Shaanxi Province. The areas with significant correlation between NPP and precipitation and temperature accounted for 9.4% and 1.5% of the total area of the province. The frequent intervention of human activities reduced the impact of climate on the changes of NPP, so human activity had gradually become the dominant factor. NPP in northern Shaanxi and Guanzhong areas was significantly correlated with evapotranspiration. The increases of NPP in these areas would have great influence on the water and heat balance. The average NPP at different land cover was farmland > forestland > grassland > garden, increasing rate of NPP at different land cover was garden > grassland > forestland > farmland, and proportional changes of NPP was grassland > garden > forestland > farmland. The increasing percentage of NPP at three gradient ranges were 14.6% (0°-5°), 25.7% (5°-25°) and 35.9% (>25°), respectively.

[Temporal and spatial change of climate resources and meteorological disasters under climate change during winter crop growing season in Guangdong Province, China.] / 气候变暖背景下广东冬种生产季气候资源和气象灾害的时空变化.

Trend analysis method was applied to analyze the general variation characteristics of the climate resources and meteorological disasters of growing season of the winter planting in Guangdong before (1961-1996) and after climate warming (1997-2015). Percentile method was employed to determine thresholds for extreme cold and drought in major planting regions, and the characteristics of extreme disasters since climate warming were analyzed. The results showed that, by comparing 1997-2015 with 1961-1996, the heat value in winter growing season increased significantly. The belt with a higher heat value, where the average temperature was ≥15 ℃ and accumulated temperature was ≥2200 ℃·d, covered the main winter production regions as Shaoguan, Zhanjiang, Maoming, Huizhou, Meizhou and Guangzhou. Meanwhile, the precipitation witnessed a slight increase. The regions with precipitations of 250-350 mm included Zhanjiang, Maoming, Huizhou, Guangzhou and Meizhou. Chilling injury in the winter planting season in the regions decreased, the belt with an accumulated chilling of <2 ℃·d covered the major geographic parts of the involved regions as Zhanjiang, Maoming, Guangzhou and Huizhou; and the belt with an accumulated chilling of 8-16 ℃·d covered the major geographic parts of Shaoguan and Meizhou. Meanwhile, the drought days decreased, the belt with drought days ≥50 included the major geographic parts of Zhanjiang, Maoming, Huizhou, Guangzhou and the belt with drought days <50 included the major geographic parts of Shaoguan. The typical case of the extreme disasters showed that the extreme chilling injury and drought in the main producing regions should not be overlooked. Maoming, Huizhou and Meizhou were at higher risk of extreme chilling injury, followed by Shaoguan and Guangzhou. Zhanjiang and Maoming faced the highest risk of extreme drought, Huizhou and Guangzhou took the second place, Shaoguan and Meizhou went last. During 1997-2015, the heat of winter season increased significantly, the trend of chilling and drought decreased, however, the extreme disasters occurred frequently and the risks were higher in winter production areas. It was suggested that the winter planting should be closely integrated with climate resources and the occurrence law of meteorological disasters in growing season.

Ergosterol and Water Changes in Tricholoma matsutake Soil Colony during the Mushroom Fruiting Season.

The purpose of this study is to understand spatio-temporal changes of active fungal biomass and water in Tricholoma matsutake soil colonies during the mushroom fruiting season. The active fungal biomass was estimated by analyzing ergosterol content at four different points within four replicated locations in a single circular T. matsutake colony at Ssanggok valley in the Sogri Mt. National Park in Korea during 2003 to 2005. The four points were the ahead of the colony, the front edge of the colony and 20 cm and 40 cm back from the front edge of the colony. Ergosterol content was 0.0 to 0.7 µg per gram dried soil at the ahead, 2.5 to 4.8 µg at the front edge, 0.5 to 1.8 µg at the 20 cm back and 0.3 to 0.8 µg at the 40 cm back. The ergosterol content was very high at the front edge where the T. matsutake hyphae were most active. However, ergosterol content did not significantly change during the fruiting season, September to October. Soil water contents were lower at the front edge and 20 cm back from the front edge of the colony than at the ahead and 40 cm back during the fruiting season. Soil water content ranged from 12 to 19% at the ahead, 10 to 11% at the edge, 9 to 11% at the 20 cm back and 11 to 15% at the 40 cm back. Our results suggest that the active front edge of the T. matsutake soil colony could be managed in terms of water relation and T. matsutake ectomycorrhizal root development.

Ergosterol and Water Changes in Tricholoma matsutake Soil Colony during the Mushroom Fruiting Season

The purpose of this study is to understand spatio-temporal changes of active fungal biomass and water in Tricholoma matsutake soil colonies during the mushroom fruiting season. The active fungal biomass was estimated by analyzing ergosterol content at four different points within four replicated locations in a single circular T. matsutake colony at Ssanggok valley in the Sogri Mt. National Park in Korea during 2003 to 2005. The four points were the ahead of the colony, the front edge of the colony and 20 cm and 40 cm back from the front edge of the colony. Ergosterol content was 0.0 to 0.7 microg per gram dried soil at the ahead, 2.5 to 4.8 microg at the front edge, 0.5 to 1.8 microg at the 20 cm back and 0.3 to 0.8 microg at the 40 cm back. The ergosterol content was very high at the front edge where the T. matsutake hyphae were most active. However, ergosterol content did not significantly change during the fruiting season, September to October. Soil water contents were lower at the front edge and 20 cm back from the front edge of the colony than at the ahead and 40 cm back during the fruiting season. Soil water content ranged from 12 to 19% at the ahead, 10 to 11% at the edge, 9 to 11% at the 20 cm back and 11 to 15% at the 40 cm back. Our results suggest that the active front edge of the T. matsutake soil colony could be managed in terms of water relation and T. matsutake ectomycorrhizal root development.