Changes In Vegetation Cover Research Articles

Enhancing resilience against geological hazards and soil erosion through sustainable vegetation management: A case study in Shaanxi Province

As an important component of terrestrial ecosystems, vegetation performs a necessary function in linking the atmosphere, hydrosphere, biosphere as well as soil sphere. The response of vegetation to its driving factors has been a hot research issue that needs to be further explored. Here, the temporal and spatial changes in vegetation cover in Shaanxi Province from 2000 to 2020 was characterized, and the responses to topographic elements, climate factors, geological hazards, and human activities was addressed. The outcomes proved that the average annual vegetation coverage in Shaanxi Province displayed a slight upward trend with a growing rate of 0.0545/10a. Specifically, enhanced vegetation index (EVI) increased significantly in most parts of the study area, while EVI decreased significantly in the border areas of Xi'an and Xianyang. There are differences in the effects of the driving factors on vegetation change during the study period. According to correlation analysis, vegetation was positively associated with temperature and negatively associated with precipitation. In addition, when the elevation was under 2500 m, EVI increased with elevation, while when the elevation used to be above 2500 m, EVI decreased with elevation. Moreover, geological disasters and soil erosion are the major driving factors in the reduction of vegetation cover. Human activities and national policies are the main driving factors for vegetation recovery in the study area. The results of the study are of great significance for ecosystem monitoring and provide a scientific basis for ecosystem restoration.

El Niño–Southern Oscillation (ENSO)-driven hypersedimentation in the Poechos Reservoir, northern Peru

Abstract. Although extreme El Niño events (EENEs) have always impacted hydrological anomalies and sediment transport in South America, their intensification by global warming and their association with changes in human activities and land cover after humid periods may lead to the acceleration of sediment transfers in river systems and dam reservoirs. This situation may threaten soil and water resources in arid and semiarid regions highly dependent on water originating from large dams. In this study, we investigated the sediment sequence accumulated in the Poechos Reservoir (northern Peru) and provided a retrospective reconstruction of the interactions of El Niño–Southern Oscillation (ENSO), agricultural practices and vegetation cover changes with sediment dynamics (1978–2019). To this end, a sediment core was dated and characterized by physical and chemical analyses (e.g., scanner tomography, X-ray fluorescence, particle size analysis) to estimate the evolution of sedimentation rates and changes in sediment sources during the last 5 decades. Sediment tracing results indicated the occurrence of changes in sediment sources associated with positive and negative phases of the Eastern Pacific index with a greater contribution of the lowland dry-forest area in comparison to that of the Andean area to sediment during the El Niño events (mean contribution of 76 %; up to 90 % during the coastal El Niño events (CENEs) of 2016–2017). This source contribution was mostly controlled by the stationary rainfall occurring during the EENEs in the lowland dry-forest area characterized by a low vegetation cover. Overall, after an extreme phase of ENSO, like after the EENE 1982–1983, the normal discharges and persistent sediment supplies from the middle- and upper-catchment parts led to river aggradation and the storage of substantial amounts of sediment in alluvial plains. In the absence of a significant EENE between 1983 and 1997, the large volume of sediment stored in the alluvial plains was exported by the EENE 1997–1998 resulting in an increase in sedimentation rate of 140 % after 1997 with a significant aggradation of the deltaic zone of the reservoir. In addition to the impact of extreme climate events on sediment dynamics, the development of agriculture along the riverine system after an extreme phase of ENSO increased the availability of sediments in the main channel of the rivers, easily transported by the next EENE. This study suggests that intensification of human activities associated with a higher frequency of extreme rainfall events amplified the quantity of sediment transported by the river system, which will significantly decrease the lifespan of the reservoir, which is essential to meeting the freshwater demands of the farmers and the populations living in this arid and semiarid region.

Heterogeneity Analysis of Spatio-Temporal Distribution of Vegetation Cover in Two-Tider Administrative Regions of China

Vegetation cover is a crucial component of regional ecological environments that plays a vital role in maintaining ecosystem balance. This investigation utilized Google Earth Engine and MODIS NDVI products to examine the spatiotemporal heterogeneity of regional vegetation coverage based on the multi-year average NDVI in China. Using the multi-year average NDVI, multi-year change trend slope, coefficient of variation, and Hurst exponent, the spatial and temporal heterogeneity of provincial and prefectural administrative regions were quantified. The results indicated an upward trend in vegetation coverage from 2000 to 2021 at both provincial and prefectural levels, with growth rates of 0.032/10a and 0.03/10a, respectively. Moreover, the multi-year average NDVI significantly correlated with regional precipitation. Notably, vegetation growth was fastest in the Loess Plateau, while degradation was observed in southern Jiangsu and northern Zhejiang. Additionally, the degree of vegetation cover change in Ningxia and Macau was particularly prominent. These findings support the effectiveness of the Loess Plateau greening project and highlight the potential cost of economic and population growth on the ecosystem in eastern and southeastern coastal areas, where local vegetation degradation occurs. This study can serve as a valuable reference for ecosystem restoration and developmental planning at the administrative regional level, with the goal of enhancing vegetation management and conservation efforts in China.

Dynamic monitoring of vegetation coverage in weibei dry plateau based on remote sensing

Taking Fu County, a typical area of Weibei dry plateau, as the research object, the normalized difference vegetation index ( NDVI ) was calculated by using Landsat 8 OLI remote sensing image. On this basis, the vegetation coverage in the study area was estimated and graded according to the binary pixel model, and the dynamic changes of vegetation coverage in the study area from 2013 to 2017 were quantitatively analyzed. Results showed that the overall NDVI value in the study area increased from 2013 to 2017. The vegetation cover in the study area is dominated by extremely high vegetation cover. The coverage area of low, medium and high vegetation cover decreases, and the coverage area of extremely high and extremely low vegetation cover increases. The coverage area of high vegetation and extremely high vegetation cover accounts for more than 75% of the study area. The study area showed a transfer trend of extremely low vegetation→low vegetation→medium vegetation→high vegetation coverage. The vegetation coverage generally developed to a good trend, but there was also a transfer of high vegetation coverage to medium vegetation coverage. The areas with the greatest changes in the study area are mainly concentrated in the northwest and near the southern Damagou, and the high NDVI area of Ziwuling National Nature Reserve has moved eastward and narrowed. Accuracy assessment indicates that the dynamic monitoring using the fused image time series produces results with relatively high accuracy. Bangladesh J. Bot. 52(2): 479-486, 2023 (June) Special

Dynamic monitoring of vegetation coverage in weibei dry plateau based on remote sensing

Taking Fu County, a typical area of Weibei dry plateau, as the research object, the normalized difference vegetation index ( NDVI ) was calculated by using Landsat 8 OLI remote sensing image. On this basis, the vegetation coverage in the study area was estimated and graded according to the binary pixel model, and the dynamic changes of vegetation coverage in the study area from 2013 to 2017 were quantitatively analyzed. Results showed that the overall NDVI value in the study area increased from 2013 to 2017. The vegetation cover in the study area is dominated by extremely high vegetation cover. The coverage area of low, medium and high vegetation cover decreases, and the coverage area of extremely high and extremely low vegetation cover increases. The coverage area of high vegetation and extremely high vegetation cover accounts for more than 75% of the study area. The study area showed a transfer trend of extremely low vegetation→low vegetation→medium vegetation→high vegetation coverage. The vegetation coverage generally developed to a good trend, but there was also a transfer of high vegetation coverage to medium vegetation coverage. The areas with the greatest changes in the study area are mainly concentrated in the northwest and near the southern Damagou, and the high NDVI area of Ziwuling National Nature Reserve has moved eastward and narrowed. Accuracy assessment indicates that the dynamic monitoring using the fused image time series produces results with relatively high accuracy. Bangladesh J. Bot. 52(2): 479-486, 2023 (June) Special

Influence of Cattle Grazing Methods on Changes in Vegetation Cover and Productivity of Pasture Lands in the Semi-Desert Zone of Western Kazakhstan

Influence of Cattle Grazing Methods on Changes in Vegetation Cover and Productivity of Pasture Lands in the Semi-Desert Zone of Western Kazakhstan

Analysis of Spatial and Temporal Changes in Vegetation Cover and Driving Forces in the Yan River Basin, Loess Plateau

The Yan River Basin of the Loess Plateau is a key region for ensuring the environmental protection and sustainable development of the Yellow River Basin. Therefore, it is essential to identify how vegetation cover has changed and determine the factors that have driven these changes. In this study, we applied a three-dimensional vegetation cover model to examine the spatiotemporal variation characteristics of vegetation cover at the watershed scale in the Yan River Basin from 2001 to 2020 and forecast future trends. Subsequently, the driving forces of fractional vegetation cover (FVC) change were quantified based on meteorological, surface, and anthropogenic factors to explore the common driving relationships among these factors. (1) The accuracy of 3DFVC is better than that of FVC in the Yanhe River Basin, where the terrain is complex. (2) The temporal change trends indicated that the vegetation cover in the Yan River Basin significantly recovered and the basin FVC increased rapidly from 2001 to 2013 (S = 0.0152/a, p < 0.01) and increased gradually from 2013 to 2020 (S = 0.0015/a). The main reason for the increase in vegetation cover was the enhanced growth of medium FVC. (3) The vegetation spatial distribution showed that the FVC values varied substantially from north to south, indicating spatial heterogeneity, and 83.9% of the area presented a trend of increasing vegetation. Furthermore, vegetation cover was predicted to improve in the future. (4) The spatial heterogeneity of FVC was mainly influenced by relative humidity and rainfall, and the spatial variations in FVC were mainly determined by climate factors. Land use and cover change variations, which are influenced by human activities, represent major factors underlying the observed spatial heterogeneity. Most interactions between driving factors showed two-way enhancement or non-linear enhancement, with relative humidity and land use patterns presenting the strongest explanatory power. This study provides a scientific basis for vegetation conservation in the Yan River Basin and contributes theoretical support for decision-making regarding ecological environmental protection in the Loess Plateau and sustainable development in the Yellow River Basin.

Characterization of water status and vegetation cover change in a watershed in Northeastern Brazil

The existing water scarcity in the Brazilian semiarid region, associated with anthropic activities, imply in the degradation of the watersheds present in the Caatinga. Therefore, the objective of this study was to characterize water and vegetation cover changes in the Ipanema River Watershed (IRW). IRW is inserted in municipalities that make up the dairy basins of the states of Alagoas and Pernambuco, one of the main economic activities in the Northeast of Brazil (NEB). Land use and land cover (LULC) maps, Modified Normalized Difference Water Index (MNDWI) and rainfall product via TerraClimate were used in the study. The MNDWI was based on the annual mean between 2010 and 2020 for the dry and rainy periods. For rainfall patterns and variability, pixel values were extracted and submitted to the Inverse Distance Weighted (IDW) interpolation method. We highlight the inverse relationship between the categories Forestry, Agriculture and Cattle Raising, with a decrease in the area of Caatinga due to agriculture and cattle raising. In the dry period via MNDWI there was higher water availability in 2010, 2017, 2018, 2019 and 2020, the exceptions were the years 2013–2016. In the rainy season, clouds interfered in the MNDWI analyses, with lower water availability in 2013, the exceptions were 2017 and 2018. Comparatively, the images from 2010 to 2020 via MNDWI, showed a water reduction in the IRW, mainly in the southern portion. For the dry period, the years 2011, 2012, 2016 and 2019 showed less than 138 mm of rainfall, especially in 2016 (<64 mm). In the rainy season, the years 2012, 2013, 2016, 2018 and 2019 also showed less than 482 mm of rainfall, with 2012 and 2016 standing out (<101 mm), mainly, the months with the highest rainfall record at IRW. The results obtained in this study show that droughts in the NEB continue to the present day, followed by an increase in water deficit. Anthropic action implies environmental degradation in one of the most threatened ecosystems (Caatinga), affecting mainly the water resource, an important factor in the survival of the local population and in the territorial dynamics.

Spatial and Temporal Variation in Vegetation Cover and Its Response to Topography in the Selinco Region of the Qinghai-Tibet Plateau

In recent years, the vegetation cover in the Selinco region of the Qinghai-Tibet Plateau has undergone significant changes due to the influence of global warming and intensified human activity. Consequently, comprehending the distribution and change patterns of vegetation in this area has become a crucial scientific concern. To address this concern, the present study employed MODIS-NDVI and elevation data, integrating methodologies such as trend analysis, Hurst exponent analysis, and sequential cluster analysis to explore vegetation cover changes over the past 21 years and predict future trends, while examining their correlation with topographic factors. The study findings indicate a fluctuating upward trend in vegetation cover, with a notable decrease in 2015. Spatially, the overall fractional vegetation cover (FVC) in the study area showed a basic stability with a percentage of 78%. The analysis of future trends in vegetation cover revealed that the majority of areas (68.26%) exhibited an uncertain trend, followed by stable regions at 15.78%. The proportion of areas showing an increase and decrease in vegetation cover accounted for only 9.63% and 5.61%, respectively. Elevation and slope significantly influence vegetation cover, with a trend of decreasing vegetation cover as elevation increases, followed by an increase, and then another decrease. Likewise, as the slope increases, initially, there is a rise in vegetation cover, followed by a subsequent decline. Notably, significant abrupt changes in vegetation cover are observed within the 4800 m elevation band and the 4° slope band in the Selinco region. Moreover, aspect has no significant effect on vegetation cover. These findings offer comprehensive insights into the spatial and temporal variations of vegetation cover in the Selinco region and their association with topographic factors, thus serving as a crucial reference for future research.

Effects of Groundwater Depth on Vegetation Coverage in the Ulan Buh Desert in a Recent 20-Year Period

As a typical desert in the Inner Mongolia Autonomous Region, the Ulan Buh Desert has a dry climate and scarce precipitation all year round. Groundwater has become the main factor limiting the growth of vegetation in this region. It is of great significance to study the influence of groundwater depth on the spatial distribution pattern of vegetation in this region. Based on the PIE-Engine platform and using long-term time-series Landsat data, this paper analyzed the spatial–temporal distribution characteristics and trends in vegetation coverage in the Ulan Buh Desert in the last 20 years using a pixel dichotomy model and the image difference method. The Kriging interpolation method was used to interpolate the groundwater depth data from 106 monitoring wells in the Ulan Buh Desert over the past 20 years, and the spatial distribution characteristics of groundwater depth in the Ulan Buh Desert were analyzed. Finally, the correlation coefficient between changes in vegetation coverage and changes in groundwater depth was calculated. The results showed the following: (1) The vegetation coverage in the Ulan Buh Desert was higher in the periphery and lower in the center of the desert. The overall vegetation level showed an increasing trend year by year; the growth rate was 4.73%/10 years, and the overall vegetation cover showed an improving trend. (2) The overall groundwater depth in the Ulan Buh Desert was deep in the southwest and shallow in the northeast. In the past 20 years, the groundwater depth in the Ulan Buh area has become shallower, and the ecological condition has gradually improved. (3) On the whole, the vegetation coverage varied with the groundwater depth, and the shallower the groundwater depth, the greater the vegetation coverage. When the groundwater depth increased to more than 4 m, the change in the groundwater depth had a significant effect on the vegetation coverage. However, when the groundwater depth was greater than 6 m, the change in the groundwater depth had no significant effect on the change in vegetation coverage.

Vegetation as an ecological indicator in assessing environmental restoration in mining areas

As global demand for natural resources escalates, the environmental impact stemming from resource extraction has risen to the forefront of contemporary discussions. This paper probed the potential of using vegetation cover as an ecological barometer to gauge the level of environmental damage and restoration in mining areas: a decline in vegetation cover may signify detrimental impacts from intense mining activities, while an increase may indicate effective local environmental stewardship. Therefore, this paper undertook an assessment and discussion of mining damage and environmental management at China's Ta'ershan Mining Area since 2007, calculating and visualizing FVC (Fractional Vegetation Cover) of the Ta'ershan Mining Area to track changes in vegetation cover between 2007 and 2021. Changes in vegetation cover in the Ta'ershan Mining Area could act as a reflection of both mining-induced damage and subsequent successful environmental management by local authorities, providing a practical way to evaluate ecological effects in resource development.

Temporal and spatial analysis of vegetation cover change in the Yellow River Delta based on Landsat and MODIS time series data.

Based on the Landsat normalized difference vegetation index (NDVI) and the NDVI product of MODIS, this study synthesized two kinds of time-series images. The features were selected according to the characteristics of the time series, and the random forest algorithm was used for classification. Based on the classification results and GIS spatial analysis, the temporal and spatial changes in vegetation cover in the Yellow River Delta from 2000 to 2020 were studied. The results showed that from 2000 to 2020, the vegetation first increased and then decreased, and the dynamic degree of land cover change was generally low. The monthly average minimum NDVI values during the vegetation growth period mostly occurred before 2010, and the maximum values occurred after 2010. From the spatial perspective, the average vegetation area of the Yellow River Delta accounted for 31.54% of the total study area; specifically, the spatial pattern of vegetation distribution was relatively fixed, and the fixed vegetation area accounted for 63.90% of the total vegetation area. The spatial distribution had significant differences, and the vegetation was distributed radially from the center of the Yellow River to the periphery, with significant fragmentation found outside the watershed. The Yellow River had a strong interference with vegetation growth, and the stable vegetation distribution areas were concentrated near the Yellow River. The correlation coefficient between vegetation distribution and the location of the Yellow River was - 0.9964.

Contributions of natural and anthropogenic factors to historical changes in vegetation cover and its future projections in the Yellow River basin, China

AbstractThe fragile ecology of the Yellow River basin (YRB) is vulnerable to global warming and human activities. As the second largest river in China, the YRB covers the subhumid, semi‐arid, arid and alpine climate zones, with considerably spatial differences in vegetation cover (VC), thus demonstrating substantial variations in response to climate change. In this study, characteristics of VC variations in different climate zones of the YRB during 1982–2019 were analysed, impacts of climate change and human activities on VC variations were identified, and possible VC variations in the future were projected under different climate scenarios. Results show that NDVI in the YRB significantly increased at a rate of 2.3 × 10−3 year−1 from 1982 to 2019, especially in the middle reaches of the YRB. Temperature is the main driver of VC variations in the source region of the YRB (alpine zone), wherein the warming trend contributes to the greening. The internal variability of VC is also influenced by temperature, with a marginal effect of precipitation minus evaporation (P − E). In the middle and lower reaches of the YRB consisting of arid, semi‐arid, and subhumid zones, VC benefited only from the warming trend and had a less relationship with the internal variability of temperature, whereas the internal variability of VC was influenced by P − E and had a weaker relationship with the P − E trend. Contributions of climate change to VC variations in the source region and middle and lower reaches of the YRB are approximately 62%, 42%, and 27%, respectively. Human activities considerably impact the ecological environment but mostly play a positive role. In the future, VC will increase in the YRB, especially under the SSP5‐8.5 scenario, and VC reveals the most prominent changes in the lower reaches. This study suggests that climate change might be favourable to VC in YRB, and emphasizes that human activities should adapt to climate change in an orderly manner.

Morphometry of the cold-climate Bory Stobrawskie Dune Field (SW Poland): Evidence for multi-phase Lateglacial aeolian activity within the European Sand Belt

Abstract Aeolian dunes have been widely identified in the European Sand Belt, which was formed during the Pleniglacial and Late Glacial when cold and dry climatic conditions were favorable for intense Aeolian processes. In this study, we mapped and analyzed the fixed Bory Stobrawskie Dune Field (SW Poland) to determine factors that drive the evolution of dunes, expressed by the occurrence of different dune types and their spatial patterns. The study identified the longitudinal zonation within the dune field, as shown by the changeable proportion of specific dune types comparable to low-latitude dune fields. However, climatically controlled periodic and low sand supply combined with a changing vegetation cover caused the non-continuous and multi-phase evolution of the dune field. Additionally, we found that a dense pattern of streams has controlled the extent of the dune field. The trapping of sand by rivers led to a limitation of the dune field expansion; on the other hand, the supply of sand into rivers led to overloading of the fluvial system, affecting their transformation into braided rivers.

WATER AND VEGETATION COVER CHANGE DETECTION USING MULTISPECTRAL SATELLITE IMAGERY: A CASE STUDY ON JHENAIDAH DISTRICT OF BANGLADESH

Water and vegetation are the two most important land cover features of any natural setting. The Jhenaidah District of Bangladesh is known for its remarkable physical geography, featuring diversified vegetation cover and numerous oxbow lakes. Due to several anthropogenic causes, this majestic land cover is degrading rapidly. This study examines the study area's spatiotemporal water and vegetation cover change from 1990 to 2020. Freeware Satellite imageries from the USGS data archive were used as the main secondary data source, ensuring consistency by collecting dry season images. In addition, open discussions with the residents provided valuable insights into the situation. Remote sensing (RS) based Soil Adjusted Vegetation Index (SAVI) was used to detect the water and vegetation cover from the preprocessed satellite imageries. Furthermore, the water and vegetation cover were classified based on a scheme developed by field observation and discussion with the residents. The analysis reveals an overall 84.47% decline in dense vegetation, 63.01% decline in deep water cover, 185.69% increase in shallow water cover, and 16.08% increase in agricultural lands within the mentioned time frame. Almost all the upazila of Jhenauidah district experience the criticality of the land cover change. Among the upazila, Shailkupa faced an unprecedented decline in deep water (95.29%), and Kaliganj faced a heavy decrease in forested vegetation (92.40%). In contrast, shallow water expanded significantly in Sadar Upazila (251.37%), and agricultural land experienced the most increasing trend (32.70%) in Shailakupa Upazila.

Past and projected future patterns of fractional vegetation coverage in China

With the intensifying climate change and the strengthening ecosystem management, quantifying the past and predicting the future influence of these two factors on vegetation change patterns in China need to be analyzed urgently. By constructing a framework model to accurately identify fractional vegetation coverage (FVC) change patterns, we found that FVC in China from 1982 to 2018 mainly showed linear increase (29.5 %) or Gaussian decrease (27.4 %). FVC variation was mainly affected by soil moisture in the Qi-North region and by vapor pressure deficit in other regions. The influence of environmental change on FVC, except for Yang-Qi region in the southwest (−2.0 %), played a positive role, and weakened from the middle (Hu-Yang region: 2.7 %) to the northwest (Qi-North region: 2.4 %) to the east (Hu-East region: 0.8 %). Based on five machine learning algorithms, it was predicted that under four Shared Socioeconomic Pathways (SSPs, including SSP126、SSP245、SSP370、SSP585) from 2019 to 2060, FVC would maintain an upward trend, except for the east, where FVC would rapidly decline after 2039. FVC in the eastern region experienced a transition from past growth to future decline, suggesting that the focus of future ecosystem management should be on this region.

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.

Wetland vegetation cover changes and its response to climate changes across Heilongjiang-Amur River Basin.

The Heilongjiang-Amur River Basin is one of the largest and most complex aquatic systems in Asia, comprising diverse wetland resources. The wetland vegetation in mid-high latitude areas has high natural value and is sensitive to climate changes. In this study, we investigated the wetland vegetation cover changes and associated responses to climate change in the Heilongjiang-Amur River Basin from 2000 to 2018 based on the growing season (May to September) climate and LAI data. Our results indicated that the wetland LAI increased at 0.014 m2·m-2/yr across Heilongjiang-Amur River Basin with the regional climate showed wetting and warming trends. On a regional scale, wetland vegetation in China and Russia had positive partial correlation with solar radiation and minimum air temperature, with precipitation showing a slight lag effect. In contrast, wetland vegetation in Mongolia had positive partial correlation with precipitation. These correlations were further investigated at different climate intervals. We found the precipitation is positively correlated with LAI in the warm regions while is negatively correlated with LAI in the wet regions, indicating an increase in precipitation is beneficial for the growth of wetland vegetation in heat sufficient areas, and when precipitation exceeds a certain threshold, it will hinder the growth of wetland vegetation. In the cold regions, we found solar radiation and minimum air temperature are positively correlated with LAI, suggesting SR and minimum air temperature instead of mean air temperature and maximum air temperature play more important roles in affecting the wetland vegetation growth in the heat limited areas. The LAI was found to be negatively correlated with maximum air temperature in the arid areas, indicating excessive temperature would inhibit the wetland vegetation growth when the water is limited. Our investigation can provide a scientific foundation for the trilateral region in wetland ecosystem protection and is beneficial for a more comprehensive understanding of the responses of wetlands in the middle and high latitudes to climate change.

Use of Geospatial Technologies to Identify the Impact of Deforestation and its Associate Event (Soil Erosion) in the North-Bilate Watershed, Southern Ethiopia

The rapid population growth in Southern Ethiopia's North-Bilate watershed, specifically in the Boyo Lake area, has resulted in widespread deforestation and soil erosion, affecting the livelihood of farmers. Thus, the current study aimed at assessing the effects of land cover change on soil erosion and agricultural land. For this purpose, 2 lands sat ETM images for the years 2000 and 2020 which have 30*30m resolution were used. The main trajectories of land use change are based on five land use classes which are farmland, built-up area, forest, bare land, water, and open area derived from the remotely sensed images. The analysis showed that Bushland and built-up areas increased with a rate of 1.2 and 2.6 ha/year between 2000 and 2020, respectively. On the contrary, woodland, farmland, and bare land had decreased by 0.2, 0.4, and 3.2 ha/year in the same study period. The NDVI value response of the study period clearly shows the highest value for vegetation cover change, as the maximum value was +0.91 in 2000 and the minimum value was -0.38 in 2020. The dramatic expansion of settlements was due to the runoff of farmland, woodland, and bare land within the allotted period due to rapid population growth and migration from the surrounding rural areas, poor land management, and illegal housing. In summary, signs of deforestation and consequent soil erosion due to population growth, agricultural expansion, forest depletion, and mismanagement are leading to reductions in vegetation cover and agricultural productivity. To minimize soil erosion, physical measures such as terracing and dams should be implemented. In addition, to preserve and increase the biodiversity of the study area, the planting of various types of native vegetation and plantation tree species should be carried out with a viable afforestation and reforestation program.

How Did the Southwest China Mountains Turn Green from 2000 to 2020? A Case Study in Chongqing

Vegetation, as a comprehensive ecological indicator of environmental change, plays an essential role in terrestrial ecosystems. Dramatic climate change and increasing anthropogenic disturbances have led to a profound change in vegetation cover. This study employed Moderate Resolution Imaging Spectroradiometer (MODIS) and other relevant data in Southwest China mountains, using Chongqing as a case study, to explore the variation in Normalized Difference Vegetation Index (NDVI) and its spatial differentiation mechanisms, quantify the relative contributions of climate change and human activities to these variations, and assess the effects of ecological policies, including afforestation, mountain closure forestry and natural forest conservation, and agricultural improvement. Results showed that the spatial distribution of annual NDVI, on average, varied 0.109 to 0.929, with the rate varying from −0.033 to 0.017 yr−1. NDVI was improved in 83.4% areas of Chongqing, and human activities contributed 69.1% of revegetation, whereas climate contributed 30.9%. On the other hand, human activities and climate change contributed 76.3% and 23.7% to vegetation degradation in 17.6% areas, respectively. Moreover, the explanatory power of anthropogenic factors on spatial differentiation of NDVI were stronger than that of climatic factors, and land use type was the dominant factor. The cumulative afforestation area, effective irrigation rate, fertilizer application, and total agricultural machinery power of the whole city was extremely significantly correlated with NDVI (p &lt; 0.01), and the vegetation cover fluctuation in the region affected by natural forest protection and mountain closure forestry project was much more stable than that in non-protected areas, which to a certain extent reflected the effective implementation of local ecological protection, agricultural improvement, and other related policies.