Changes In Vegetation Cover Research Articles

A categorical quantification of the effects of vegetation restorations on streamflow variations in the Loess Plateau, China

The Loess Plateau is the world’s largest and most typical loess accumulation area, and its recent change in vegetation cover has had significant hydrological effects. Understanding the impact of vegetation restorations in this region is essential for local water security and the sustainable development of Loess regions. This investigation concentrates on the upper basin of the Beiluo River, a representative watershed on the Loess Plateau. Using the coupled application of the hydrological model and the DFI baseflow segmentation method, as well as the analysis of extreme land cover transfer scenarios, the impact of typical land cover transition categories on the watershed runoff process on the Loess Plateau is systematically evaluated. Depending on the change in runoff introduced by the unit transfer area, a rapid estimation method for river runoff in the Loess Plateau is proposed. The results show that base flow contributes considerably to river runoff on the Loess Plateau, and the SWAT-DFI coupling has substantially improved the hydrological model’s simulation accuracy during the dry season. From 1985 to 2020, the primary land cover transfer categories in the upper basin of the Beiluo River were agricultural land to the forest (AL2F), agricultural land to pasture (AL2P), pasture to agricultural land (P2AL), and pasture to the forest (P2F), of which P2AL is the only form of transfer that increases discharge. From a spatial perspective, the intensity of the impact of AL2F and AL2P on runoff is greater in the upstream region than in the downstream region. From the standpoint of land cover transfer type, the intensity of runoff depth change caused by transfer per unit area varied, which was primarily manifested by the fact that the impact of AL2F was greater than that of AL2P, both of which were greater than that of P2AL and significantly higher than that of P2F. The proposed rapid estimation method based on land cover transfer equivalents can rapidly estimate river runoff changes and spatial distribution under various land cover change conditions, which is critical for understanding the hydrological effects of vegetation restoration on the Loess Plateau. The quantified effect of land cover change on runoff and the proposed quick estimation approach can serve as benchmarks for water security and ecological restoration on the Loess Plateau and other loess accumulation areas around the globe.

Dune belt restoration effectiveness assessed by UAV topographic surveys (northern Adriatic coast, Italy)

Abstract. Unoccupied aerial vehicle (UAV) monitoring surveys are used to assess a dune restoration project in the protected natural area of the Bevano River mouth on the northern Adriatic coast (Ravenna, Italy). The impacts of the installed fences to aid dune development are quantified in terms of sand volume and vegetation cover changes over 5 years using a systematic data processing workflow based on structure-from-motion (SfM) photogrammetry and the Geomorphic Change Detection (GCD) toolset applied to two drone surveys in 2016 and 2021. Accuracy assessment is performed using statistical analysis between ground-truth and model elevation data. Results show that the fence proves to be effective in promoting recovery and growth since significant sand deposition was observed along the dune foot and front – a total area of 3799 m2, volume of 1109 m3, and average depositional depth of 0.29 m. Progradation of around 3–5 m of the foredune and embryo development were also evident. There was a decrease in blowout features of about 155 m2 due to increased deposition and vegetation colonization. There was also an average percent increase of 160 % on wave-induced driftwood and/or debris along the beach and of 9.6 % vegetation within the fence based on the cover analysis on selected transects. Erosion of around 1439 m2 is apparent mostly at the northern portion of the structure, which could be accounted for by the aerodynamic and morphodynamic conditions around the fence and its configuration to trap sediments and efficiency in doing so. Overall, dune fencing coupled with limiting debris cleaning along the protected coast was effective. The proposed workflow can aid in creating transferable guidelines to stakeholders in integrated coastal zone management (ICZM) implementation on Mediterranean low-lying sandy coasts.

The temporal variation of sediment connectivity from 1982 to 2020 in the Wei River basin, China

AbstractSediment connectivity is a valuable metric that characterizes the relationship between sediment transport from the source to the sink, and the ease of sediment erosion. Over the past four decades, changes in land use types and vegetation cover have significantly altered sediment dynamics in the Wei River basin. In this study, we used the index of connectivity (IC) to assess the temporal changes in sediment connectivity at a watershed scale. We employed Landsat images to analyse the relationship between changes in vegetation cover or land use type and sediment connectivity. We used factor detector and interaction detector in Geodetector to analyse the importance and impact of vegetation and slope on IC changes. We assessed the correlation of sediment yield and connectivity to validate our results and it shows that IC has strong or moderate positive correlation with sediment yield from eight out of nine stations in the Wei River Basin. Our findings demonstrate that soil and water conservation measures, as well as the grain for green project, have led to the transformation of cropland and grassland into woodland. This change is reflected in the decrease of the maximum IC value from 6.24 to 5.72 in the Beiluo sub‐basin, indicating a decreasing trend in sediment connectivity. Although the maximum IC value increased from 5.76 to 5.08 in the Jing sub‐basin, driven by human activity, showing an increasing trend. Furthermore, the IC value decreased in the western part of the Wei sub‐basin. Overall, sediment connectivity exhibits a weak decreasing trend in most regions of the Wei River basin, while it shows an increasing trend slightly in the Jing sub‐basin. The correlation coefficients ranged from 0.47 to 0.86, with sediment yield being moderately or strongly correlated with IC. Our study identified vegetation, human activity, and slope as the main influencing factors of IC. The results of factor detector showed that the q value of vegetation was 0.63 and the slope was 0.1, Vegetation played a major role in the change of IC. The results of interaction detector showed that interaction between vegetation and slope was greater than the single factor. The temporal variability of sediment connectivity in the basin provides valuable insights for sediment transport management. Our research highlights the importance of studying sediment connectivity and offers proposals for measures that can be taken to address sediment transport challenges in the Wei River basin.

Detection of Vegetation Cover Changes from 1988-2022 in the University of Baghdad Campus by Remote Sensing and GIS Techniques (Normalized Difference Vegetation Index (NDVI) and Soil-Adjusted Vegetation Index (SAVI)

This study aims to investigate changes in vegetation cover of the University of Baghdad campus by Normalized Difference Vegetation Index (NDVI) and Soil-Adjusted Vegetation Index (SAVI) as a tool to determine the changes in vegetation cover on the University landscape were used for the period 1988 and 2022 for two seasons (Winter and Summer). Land cover was divided into four categories: Barren & buildings, Low, Medium, and Dense vegetation. The results showed an increase in NDVI values in winter (-0.2-0.5), and (-0.1-0.9) in 1988, and 2022 respectively, and recorded in summer (-0.3-0.5) and (-0.04-0.4) in 1988, and 2022 respectively. The highest value was recorded in winter of 2022. Barren & buildings recorded the highest value 1470630 Km2 with 43% in summer of 1988 while in 2022 recorded 1411156 Km2 with 40%, for both seasons. The Low vegetation recorded the highest value 130031 Km2 with 377% in winter 1988 and the lowest was recorded at 941671 Km2 with 28% in summer 2022. Medium vegetation was recorded the highest 787580 Km2 with 22% in winter 2022 and lowest 667730 Km2 with 19 %. Dense vegetation was the highest 413614 Km2 with 12 % in summer 2022 while the lowest was recorded 211763 Km2 with 6 % in winter 1988. SAVI values were recorded in winter (-0.3-0.7), (-0.1-0.4) in 1988 and 2022 respectively and in summer (-0.4 - 0.7)(-0.06 - 0.6) in 1988 and 2022 respectively. The results showed slight differences from NDVI values of vegetation cover (Dense). The integration of remote sensing and geographic information systems is an effective and sustainable tool for studying land cover changes in order to obtain reliable and accurate rapid and economical results.

Impact of increasing vegetation coverage on gaining and losing streams in an arid endorheic river watershed

AbstractTo improve the ecology in northern China, the Chinese government has launched a series of revegetation projects. However, the impact of increasing vegetation coverage on gaining and losing streams remains largely unexplored, particularly in arid endorheic watersheds with frequent exchanges of water and other materials between surface water and groundwater. To address this, we modified the vegetation growth module of the soil and water assessment tool (SWAT) to simulate the vegetation coverage change proposed for the middle and lower reaches of the Bayin River. We then coupled the modified SWAT to a modular finite‐difference groundwater flow model to simulate the surface and subsurface water exchange. Hydrological, meteorological, and hydrogeological observation data were then used to build and calibrate the coupled model for the period 2001–2019. We set two vegetation coverage scenarios (non‐revegetation and vegetation) and two irrigation variants (non‐irrigation and irrigation) to investigate the impact of changes in vegetation coverage and the related irrigation variant on gaining and losing streams. The results showed that the vegetated land area and annual leaf area index both increased significantly between 2019 and 2001. The groundwater discharge to the gaining streams was more strongly affected by revegetation and related irrigation than the groundwater recharge from the losing streams. Irrigation related to revegetation emphasizes the effect of revegetation on streamflow. We suggest that in arid endorheic river basins, because of the related irrigation, revegetation has a substantial impact on groundwater level and streamflow, which is mainly composed of baseflow. Therefore, the irrigation efficiency of newly planted vegetation must be improved to stabilize the groundwater level and related ecological conditions.

Decadal changes in vegetation cover within coastal dunes at the regional scale in Victoria, SE Australia

Vegetation is a critical boundary condition for the stability of coastal dunes. Globally, vegetation cover is increasing on the coast with many dunes being stabilised in the past decades. This pattern is driven by site-specific (e.g., coastal management) and global (e.g., climatic changes) factors. This study examines changes in dune vegetation during the past six decades at the regional scale along the southeast coast of Australia to understand the relative importance of the climate and human interventions in vegetation cover change. A total area of >31,000 ha, comprising 53% of the open coast of Victoria was studied. Since the 1960's, a general trend of dune stabilisation and coastal greening has occurred with total vegetation cover increasing from 61% to 84% coverage until 2020. At the regional scale, the increase in vegetation cover has been primarily driven by both climatic-related drivers, such as rising temperature, elevating CO2 concentrations and declining windiness, and state-wide coastal management interventions (e.g., marram grass planting, fencing, fire control, grazing removal). The only areas where there was a decline in total area of vegetation was where substantial coastal recession had occurred. The decrease in vegetation is a result of a loss of land area rather than a loss of plant biomass over the dunefields. Therefore, it is considered that the overall decadal changes in both climate and coastal management are forcing the dunes toward a more stabilised state at the regional scale. At the same time, compelling local drivers (e.g., storms and local sediment deficiency) can be the most crucial factor to regulate vegetation change and shift dune mobility at the site-specific scale.

Aeolian Sediment Transport Responses to Vegetation Cover Change: Effects of Sampling Error on Model Uncertainty

AbstractAlthough it is widely known that observations of aeolian sediment transport are susceptible to large sampling errors, sample designs are frequently used that do not sufficiently reduce the measurement uncertainties inherent in the study of aeolian processes. Here, we examine the influence of sample size (n) and sampling location on uncertainty in models of aeolian sediment transport responses to vegetation cover change. We compare measurements from a stratified random array of 27 horizontal sediment mass flux samplers to vegetative cover data collected at a 1 ha site over a period of nearly 6 years. To assess the sensitivity of modeled relationships between aeolian transport and vegetative cover to sample design, we analyze statistical regressions for all possible combinations of sample size and sampler locations. We show that at least 17 randomly located samplers are needed to consistently capture the sediment mass flux response to vegetative cover change. We found that multiple statistically significant models can describe the sediment flux‐vegetative cover relationship when using smaller sample sizes, demonstrating the risks of inferring sediment transport response from an underpowered sample design. Across vegetative functional groups, we found that woody cover generally influenced aeolian sediment transport rates more than herbaceous cover, while model uncertainty at large sample sizes (n > 17) showed the limitation of using vegetative cover as an indicator of aeolian sediment transport. Our results suggest an evaluation of sampling practices in aeolian sediment transport studies may be needed to avoid inferential errors that are likely pervasive in this field of study.

Tropical forest birds after 20 years of the establishment of a reservoir: Extinction, colonization, and recolonization events

Reservoirs are fundamental for human well-being but can cause landscape changes (e.g., habitat fragmentation and loss), altering biodiversity and ecosystem services. However, we know little about reservoir long-term effects on bird communities of tropical rainforests at different temporal scales. We assessed species richness and composition changes in four consecutive periods in a reservoir area in the Colombian Tropical Andes. After 20 years of monitoring avifauna within the reservoir, we recorded 360 bird species along with 47 local extinction and 184 colonization events. We found that species richness increased by 42% during the first 11 years after reservoir establishment. After that, changes in species bird composition were largely explained by species turnover. Eighty-two percent of the expected species in the region were recorded within the reservoir area. Also, forests surrounding the reservoir are a habitat for several threatened bird species. Bird community changes observed can be explained by secondary succession, changes in vegetation cover (i.e., increase in forest area), the transformation of aquatic ecosystems, forest protection, and restoration programs focused on biodiversity conservation. Long-term systematic bird sampling in tropical forests is key to understanding biodiversity dynamics and the effectiveness of conservation actions.

Assessing long-term trends in vegetation cover change in the Xilin River Basin: Potential for monitoring grassland degradation and restoration

Under the influence of climate change and human activities, the problem of grassland degradation is becoming increasingly severe. Detection of changes in vegetation cover is crucial for a better understanding of the interaction between humans and ecosystems. This study maps changes in vegetation cover using the Google Earth Engine (GEE). We used 36 years of Landsat satellite imagery (1985–2020) in the Xilin River Basin, China, to classify grassland conditions and validated the results with field observation data. The overall classification of the model accuracy assessment was 83.3%. The Dynamic Reference Vegetation Cover Method (DRCM) was adopted to remove the effect of interannual variation of rainfall, allowing to focus on the impact of human activities on vegetation cover changes. The results identify five categories of vegetation cover changes: significantly increased, potentially increased, stable, potentially decreased, and significantly decreased. The reference level is derived from the most persistent land surface coverage across different grassland types and all years. Overall, 9.3% of the study area had a significant increase in vegetation cover, 14.2% a potential increase, 48.6% of the area showed a stable vegetation condition, 9.8% showed a potential decrease, and 18.1% a significant decrease in vegetation cover. The largest proportion of combined potential and significant reduction was 35.2% for desert grassland, where the vegetation faced the most severe reduction. This study will provide a basis for identifying grassland degradation and developing scientific management policies.

Remote sensing reveals how armed conflict regressed woody vegetation cover and ecosystem restoration efforts in Tigray (Ethiopia)

In recent years, armed conflicts are globally on the rise, causing drastic human and environmental harm. The Tigray war in Ethiopia is one of the recent violent conflicts that has abruptly reversed decades of ecosystem restoration efforts. This paper analyzes changes in woody vegetation cover during the period of armed conflict (2020–2022) using remote sensing techniques, supplemented by field testimony and secondary data. Extent of woody vegetation cover was analyzed using Normalized Difference Vegetation Index (NDVI) thresholding method from Sentinel 2 images in Google Earth Engine, and scale of de-electrification was qualitatively analyzed from Black Marble HD nighttime lights dataset, acquired from NASA's Black Marble team. The magnitude, direction as well as the mechanisms of change in woody vegetation cover varied across the region and over time. Tigray's woody vegetation cover fluctuated within 20% of the landmass. Mainly scattered to mountainous areas, the dry Afromontane forest cover declined from about 17% in 2020 to 15% in 2021, and 12% in 2022. About 17% of the overall decline was observed between 500 m and 2000 m elevation, where there is higher anthropogenic pressure. Land restoration practices meant to avert land degradation and desertification were interrupted and the area turned warfare ground. In many areas, forests were burned, the trees cut and the area became barren. The suspension of public services such as electricity for household or industrial use created heavy reliance on firewood and charcoal, further threatening to compound weather and climate. The magnitude of disturbance in a region that is already at a very high risk of desertification requires urgent national and international attention. Continued ecosystem disturbance could eventually make the domain part of a wider desert connecting the Sahel to the Afar Triangle, a scenario which may render the area uninhabitable.

The impacts of armed conflict on vegetation cover degradation in Tigray, northern Ethiopia

Efforts made to restore the degraded landscape of the Tigray region, Northern Ethiopia, over the last three decades have been relatively successful. However, an armed conflict that broke out in the region in November 2020 has significantly destroyed the restored vegetation, either directly associated with conflict (environment, pollution, fire) or indirectly (agricultural abandonment). This study aimed at assessing spatio-temporal changes in vegetation cover in a 50 km radius zone centered on Mekelle city, Tigray. Vegetation cover dynamics was evaluated using Landsat Enhanced Thematic Mapper Plus (ETM+) and Operational Land Imager (OLI) datasets for the years 2000, 2020, and 2022 and analysed using ENVI 5.3 and ArcGIS 10.8.1 software. These data were analysed using the Modified Normalized Difference Vegetation Index (MNDVI), Optimized Soil Adjusted Vegetation Index (OSAVI), and Moisture Adjusted Vegetation Index (MAVI). Based on the MNDVI, results show that vegetation cover increased in the period 2000–2020 by 179 km2 or 2% of the area, whereas in the period 2020–2022, there was a decrease in vegetation cover by 403 km2 or 5% of the area. This was accompanied by a decrease in vegetation density. These vegetation changes in 2020–2022 are attributed to the impact of armed conflict on the land surface which can include farmlands and village abandonment, spread of weeds and scrub vegetation, or failure to harvest crops. Monitoring vegetation change using Landsat data can help understand the environmental impacts of armed conflict in rural agricultural landscapes, including potential food security risks.

Anthropisation and Sustainable Management of the Sorobouly and Pâ Classified Forests in the Balé Province

The aim of this research is to study the dynamics of land use in the Sorobouly and Pâ classified forests and the factors responsible for these dynamics. These factors are both natural and anthropogenic. In the province of Balé, demographic and pastoral pressures have increased the level of degradation of the classified forests to over 20%. The methodology used is based on a diachronic analysis of Landsat images from 1998 to 2017 and on field surveys. A projection of land-use dynamics using the Markov and CA Markov cellular automaton was carried out with a view to providing decision-makers with the necessary data for decision-making. The results of image processing in 1998, 2007 and 2017 show a faster rate of degradation in the Sorobouly classified forest than in the Pâ classified forest. Dwellings and fields occupied 53.6% of the Sorobouly classified forest in 2017. Numerous human and natural factors are responsible for this regressive change in vegetation cover. The land-use simulation predicts a vegetation cover of 32.16% of the Sorobouly CF and 97% of the Pâ CF by 2027, according to the trend scenario. The green environmental and economic scenarios developed offer sustainable management alternatives for the Sorobouly classified forest

Unraveling plant-pollinator interactions from a south-west Andean forest in Colombia.

Loss of biological connectivity increases the vulnerability of ecological dynamics, thereby affecting processes such as pollination. Therefore, it is important to understand the roles of the actors that participate in these interaction networks. Nonetheless, there is a significant oversight regarding the main actors in the pollination networks within the highly biodiverse forests of Colombia. Hence, the present study aims to evaluate the interaction patterns of a network of potential pollinators that inhabit an Andean Forest in Totoró, Cauca, Colombia. The interactions between plants and potential pollinators were recorded through direct observation in 10 transects during six field trips conducted over the course of one year. Subsequently, an interaction matrix was developed, and network metrics such as connectance, specialization, nestedness, and asymmetry of interaction strength were evaluated by applying null models. An interpolation/extrapolation curve was calculated in order to assess the representativeness of the sample. Finally, the key species of the network were identified by considering degree (k), centrality, and betweenness centrality. A total of 53 plant species and 52 potential pollinator species (including insects and birds) were recorded, with a sample coverage of 88.5%. Connectance (C = 0.19) and specialization (H2' = 0.19) were low, indicating a generalist network. Freziera canescens, Gaiadendron punctatum, Persea mutisii, Bombus rubicundus, Heliangelus exortis, Chironomus sp., and Metallura tyrianthina were identified as the key species that contribute to a more cohesive network structure. The present study characterized the structure of the plant-pollinator network in a highly diverse Andean forest in Colombia. It is evident that insects are the largest group of pollinators; however, it is interesting to note that birds form a different module that specializes in pollinating a specific group of plants. On the other hand, the diversity and generality of the species found suggest that the network may be robust against chains of extinction. Nevertheless, the presence of certain introduced species, such as Apis mellifera, and the rapid changes in vegetation cover may affect the dynamics of this mutualistic network. So, it is imperative to apply restoration and conservation strategies to these ecosystems in order to enhance plant-animal interactions and prevent the loss of taxonomical and functional diversity.

Changes in Water Balance Elements in the Basins of the Largest Tributaries of Lake Baikal in the Late XX–Early XXI Century

Long-term variations in the water balance were analyzed in the basins of 20 largest tributaries of the Baikal. The values of river runoff were derived from actual data on the period from 1976 to 2019, and those of evaporation, precipitation, and potential evaporation, from ERA5-Land reanalysis since 1976 to 2020. Data were obtained to show an increase in the potential evaporation in all analyzed drainage basins by values from 0.39 to 0.62% per year since 1976 to 2020. A moderate or statistically insignificant decrease is typical of precipitation (0.25 to 0.59% per year) and water discharges, mostly due to a decrease in the summer runoff at a rate of 5.6%/10 years. The possible role of changes in vegetation cover in these processes was studied by evaluating NDVI parameter in 2019 compared with 2002 by data of space surveys MOD13A3 and MYD13A3 with MODIS spectroradiometer of Terra and Aqua satellites. A conclusion was made about the key role of precipitation in the decrease in the maximal runoff in Lake Baikal basin.

Determination and analysis of groundwater ecological level in Changling County

In order to determine and analyze the groundwater ecological level in Changling County, a total of Landsat 8 series remote sensing images from 2017 to 2021, buried depth data of 51 groundwater observation Wells and 47 phreatic salinity detection data in 2021 were collected. Based on the field investigation and laboratory experiment, the spatial and temporal changes of groundwater level and vegetation coverage in the study area from 2013 to 2017 were determined by using remote sensing technology (the Environment for Visualizing Images) and geographic information system. Through the analysis of the vegetation coverage ratio and the relationship between the groundwater depth and diving salinity, we determine the appropriate growth of vegetation in the study area of diving level and diving salinity water. The results showed that from 2017 to 2021 in the average groundwater level and vegetation cover degree decline year by year, the study area northwest shallow depth of groundwater, vegetation cover degree better, however, in the central and eastern regions, the groundwater depth is larger and the vegetation coverage degree is poor. When the depth of local groundwater is 3.3–4.5 m and the phreatic salinity is less than 0.85 g/L, the ecological water level and phreatic salinity are suitable for vegetation growth in the study area. When the depth of local water is less than 3 m, soil salinization occurs in the surface soil near the lake marsh. When the depth of local water was greater than 8.4 m, the phenomenon of soil desertification appeared in some areas of central China.

Hydro-Climatic and Vegetation Dynamics Spatial-Temporal Changes in the Great Lakes Depression Region of Mongolia

The Great Lakes Depression region basin is among the most sensitive regions to vegetation change due to climate change. This study estimated spatial-temporal changes and relationships in hydro-climate and vegetation dynamics in the basin. Studying the spatial-temporal variation between vegetation dynamics and hydro-climate in this basin is essential for assessing climate change and sustainability. This research involved an examination of the mean yearly air temperature, overall annual rainfall, fluctuations in river discharge, vegetation cover, and alterations in vegetation types within the selected basin stations. This was accomplished through the utilization of hydro-meteorological analysis, satellite assessment, land cover determination, and statistical analysis. Over the course of the study, it was observed that the average annual air temperature increased at all stations (with a positive change of Z = +1.16). The amount of precipitation decreased (Z = −0.79), especially from 2000 to 2014, and its statistical significance decreased. During the study period, average river discharge significantly decreased (Z = −3.51). Due to these combined factors, the lake’s water level also decreased (Z = −2.03). Vegetation cover change varied in high mountains, near river and lake water surfaces, and in arid regions. Changes in air temperature and precipitation in the current year determine vegetation cover. Because of the large amount of precipitation in the summer months from 2000 to 2010 and 2020, the growth of vegetation cover during that period was relatively good. This study was conducted in arid and semi-arid regions of Central Asia and demonstrates the impact of climate change on changes in vegetation cover.

Assessment of pluri-annual and decadal changes in terrestrial water storage predicted by global hydrological models in comparison with the GRACE satellite gravity mission

Abstract. The GRACE (Gravity Recovery And Climate Experiment) satellite gravity mission enables global monitoring of the mass transport within the Earth's system, leading to unprecedented advances in our understanding of the global water cycle in a changing climate. This study focuses on the quantification of changes in terrestrial water storage with respect to the temporal average based on an ensemble of GRACE solutions and two global hydrological models. Significant changes in terrestrial water storage are detected at pluri-annual and decadal timescales in GRACE satellite gravity data that are generally underestimated by global hydrological models though consistent with precipitation. The largest differences (more than 20 cm in equivalent water height) are observed in South America (Amazon, São Francisco and Paraná River basins) and tropical Africa (Congo, Zambezi and Okavango River basins). Smaller but significant (a few centimetres) differences are observed worldwide. While the origin of such differences is unknown, part of it is likely to be climate-related and at least partially due to inaccurate predictions of hydrological models. Pluri-annual to decadal changes in the terrestrial water cycle may indeed be overlooked in global hydrological models due to inaccurate meteorological forcing (e.g. precipitation), unresolved groundwater processes, anthropogenic influences, changing vegetation cover and limited calibration/validation datasets. Significant differences between GRACE satellite measurements and hydrological model predictions have been identified, quantified and characterised in the present study. Efforts must be made to better understand the gap between methods at both pluri-annual and decadal timescales, which challenges the use of global hydrological models for the prediction of the evolution of water resources in changing climate conditions.

Quantifying vegetation change and driving mechanism analysis in Sichuan from 2000 to 2020

Vegetation cover is a crucial indicator of biodiversity and ecological processes, but there are still uncertainties about the factors driving changes in vegetation. In this study, we conducted a comprehensive analysis of vegetation cover changes in Sichuan Province from 2000 to 2020 using Formation Vegetation Cover (FVC) derived from MODIS13Q1 data. Our results revealed a consistent increase in vegetation FVC, rising from 0.506 to 0.624 over the 21-year period, with an annual growth rate of 0.0028. The turning point in this growth occurred in 2006. Of significance, the expansion of vegetation covered a substantial portion, accounting for 84.76%, while the decrease constituted 13%. Elevation proved to be an effective explanatory factor, with a coefficient of 0.417, indicating its role in explaining vegetation cover changes. It is important to note that FVC trends and averages exhibited distinct patterns concerning elevation, land use, population density, topography, and soil type, while their correlation with meteorological factors was relatively weak. Concurrently, the increase in construction and urban development had a negative impact on vegetation cover.

Are we promoting green cities in Latin America and the Caribbean? Exploring the patterns and drivers of change for urban vegetation

As cities opt for green policies to address urban socio-ecological challenges it becomes important to evaluate how the urban landscape responds to them, and if these responses are strengthening the benefits of nature for all. The Latin American and Caribbean (LAC) region is one of the most biodiverse and urbanized regions of the world, which makes it imperative to understand how greening policies have impacted the distribution, accessibility, and quantity of vegetated areas in cities through time. Using a landscape ecology approach, we explored the effects of local urban dynamics on the pathways of urban vegetation in ten LAC capital cities in the last 20 years. Our results showed a great fluctuation of vegetation cover change for the region, with Santiago (Chile) losing more than 10% of its urban vegetation to Brasilia gaining 19%, while fragmentation and inequities in the distribution of vegetation increased in all cities. Cities followed four pathways of vegetation change, displaying different patterns of change in fragmentation, size of the vegetated patches and their clustering. This discloses that the greening policies and actions adopted in LAC cities led to increased vegetation cover, or avoided its loss, but did not assure a better distribution of the green and its benefits. Vegetation in LAC cities are still fragmented, where vegetation is not connected and is not equitably distributed, showing that policies in place have not addressed distributional injustice yet. This is corroborated by the assessment of drivers of change where we found social factors were the most important determinants of urban vegetation dynamics. Results from our study provide evidence for developing policies towards urban greening and connectivity, not only to prevent further biodiversity loss but also for creating more resilient communities and cities that address environmental inequities.

Analysis of Vegetation Cover Change in the Geomorphic Zoning of the Han River Basin Based on Sustainable Development

The Han River Basin, a critical water conservation and ecological barrier in Hubei Province, is intricately associated with the United Nations Sustainable Development Goals (SDGs). Research results show that vegetation cover changes are affected by multiple factors, and understanding the influences of climate change and human activities on vegetation is imperative for achieving sustainable development in the basin. Through quantitative assessment of vegetation changes in diverse landform regions, implementing adaptive ecological construction and environmental protection will foster the sustainable development of ecological civilization in the Han River Basin. This study utilizes MODIS13Q1 data and employs diverse analytical methods to investigate the characteristics of vegetation change and the interrelationships between climate change, meteorological factors, and vegetation cover in various geomorphological areas of the Han River Basin from 2000 to 2020. The results showed that (1) throughout the entire study period, the NDVI of the six types of geomorphological divisions in the Han River Basin exhibited a fluctuating upward trend, with the changes in the low-altitude hilly geomorphic regions being particularly noteworthy. (2) Within the study area, approximately 92.67% of vegetation coverage displayed an increasing trend, while 7.33% showed degradation, predominantly in plains and platforms. Notably, the area of continuous improvement (31.16%) outweighed the area of continuous degradation (3.05%), with low and middle-relief mountain areas demonstrating the most robust growth and sustainability. (3) Human agriculture activities and urbanization processes have emerged as the primary driving force behind vegetation changes in the Han River Basin. The responses of vegetation to climate change and human activities exhibited significant variations across diverse geomorphological regions. In areas characterized by vegetation improvement, the contribution rate of human activities to NDVI changes in different vegetation types surpassed 70%, with plain areas displaying the highest contribution rate at a remarkable 90%. In contrast, the plain and platform regions of the vegetation degradation area were significantly influenced by climate change. In future watershed ecological environment management, it is essential to not only recognize the dominant role of human activities in promoting the growth of mountain vegetation NDVI but also address the impact of climate change on the degradation of vegetation NDVI in plains and platforms. A comprehensive understanding of these factors is crucial for devising effective strategies to ensure sustainable development and ecological balance in the Han River Basin.