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ABSTRACT The Cerrado biome, renowned for its biodiversity and threatened by rapid land transformation, encompasses a vast savanna ecosystem in Brazil. The region is characterised by a seasonal climate, influenced by a myriad of meteorological systems creating diverse and non‐homogeneous rainfall regimes across the region. To account for this heterogeneity, we propose a novel classification of the Cerrado using rainfall data to delineate three distinct climatic regions: Eastern, Southern and Central‐West Cerrado. The Eastern region exhibited the driest and most seasonal climate, marked by high vapour pressure deficit (VPD) and predominantly open‐canopy vegetation. Conversely, the Southern region, characterised by lower seasonality, boasts a higher proportion of forest cover and lower mean VPD. The Central‐West region, encompassing diverse landscapes, featured areas with higher precipitation levels, particularly along the Amazônia border. Furthermore, we conducted trend analyses on observed station data and used CMIP6 models to evaluate future scenarios under differing emissions trajectories. While observed trends in mean rainfall were marginal, VPD demonstrated a notable upward trend of approximately 1% annually throughout the biome. Climate models indicated a substantial drying close to the Amazônia border, and wetter conditions in the southeast. All Cerrado regions are anticipated to experience amplified seasonality and VPD, with VPD projected to surge by approximately 30% (60%) under low (high) emissions scenarios by the end of the century. Notably, the transition from the dry to wet season was the most affected. Our study provides critical insights on how the climatic heterogeneity of the Cerrado shapes vegetation structure distribution and how future changes will exacerbate water stress throughout the biome. These findings underscore the importance of understanding climate variability for effective conservation and management strategies in the region. [ABSTRACT FROM AUTHOR]

Forest landscape space is the basic unit of forest landscape resources. Healthy forest landscape resources can not only improve the sustainable cycle of forest ecological service function, but also have a positive impact on human health and well-being. Evidence supports the view that the forest environment is beneficial to people's health, and further discussion of the dose response between environmental attributes and physical and mental recovery has been widely carried out by scholars. As an important component of environmental attributes, it is necessary to clarify the relationship between vegetation distribution and users' health in order to better plan, design, and utilize forest environmental resources. This study mainly used the virtual immersive forest environment video in VR, and used the difference test in SPSS 23.0 to clarify whether the distribution of vegetation in the forest environment will affect the physiological and psychological recovery effect of users. The main results are as follows: (1) Experiencing the forest environment can promote users' physiological and psychological health, and its recovery effect is significantly better than the indoor environment (p < 0.05). (2) The distribution of vegetation in the forest environment will affect users' physiological and psychological recovery effect. Among them, in the cluster and randomly distributed forest environments, the relaxation and concentration of users can be improved mainly by alleviating their negative emotions. In the evenly distributed forest environment, users mainly achieve the purpose of relaxation by improving their vitality and positive emotions. These results show that the distribution of vegetation is one of the factors for the restoration of forest environment. In the future design and management of the forest environment, the health and well-being of users can be effectively enhanced by getting involved with the vegetation distribution in the site, aiming to provide a scientific basis for the promotion of the rehabilitation function of forest landscape space and its sustainable utilization, thus promoting the sustainable development of forest resources and improving people's quality of life. [ABSTRACT FROM AUTHOR]

Biogenic volatile organic compounds (BVOCs) are regarded as important precursors for ozone and secondary organic aerosol, mainly from vegetation emissions. In the context of the expanding trend of vegetation greening, the development of high‐precision vegetation data and accurate BVOC emission estimates are essential to develop effective air pollution control measures. In this study, by integrating the multi‐source vegetation cover data, we established a high‐resolution vegetation distribution (HRVD) data set to develop a high spatio‐temporal resolution emission inventory and investigated the impact of different land cover data sets on emission simulation and impact of land cover change on BVOC emissions during 2001–2020. The annual total BVOC emissions in China for 2020 was 15.66 Tg, which were mainly from trees. The emissions simulated by CNLUCC and MODIS data sets were 1.53% and 1.72% higher than those simulated by HRVD data sets, respectively. The spatial distribution of emission differences was consistent with that of land cover differences. The simulated BVOC emissions by the HRVD data set had the best accuracy as they improved the bias between modeling and observation from 69.06% to 65.35% and decreased the underprediction of observations by a factor of 2.13 compared with simulation by MEGAN default vegetation data. The annual BVOC emissions caused by changing vegetation distribution and LAIv (LAI of vegetation covered surfaces) enhanced at a rate of 72.06 Gg yr−1 during 2001–2020. LAIv was the main driver of emission variations. The total OH reactivity of the resulted BVOC emissions increased at a rate of 1.59 s−1 yr−1, with isoprene contributed the most. Plain Language Summary: Biogenic Volatile organic compounds (BVOCs) are the key precursors of fine particulate matter and ozone, that mainly from vegetation emissions. To help to develop effective air pollution control measures in the context of expanding vegetation coverage for realizing carbon neutralization in China, it is urgent to develop highly precise vegetation data and accurately estimate BVOC emission. A high‐resolution vegetation distribution data set was established through integrating multi‐source vegetation cover data. Using it, the simulated annual BVOC emission in China was 15.66 Tg and mainly emitted from trees. Emissions from varied growth forms had different compound compositions. The BVOC emission simulated using the high‐resolution vegetation distribution data set we developed had better accuracy than that using the single vegetation databases. The annual BVOC emissions caused by changing vegetation cover and leaf area index (LAI) enhanced at a rate of 72.06 Gg yr−1 during 2001–2020. LAI was the main driver of BVOC emission variations. The interannual variation and its spatial pattern of the OH loss rates of BVOCs during 2001–2020 were consistent with that of BVOC emissions, especially isoprene. Key Points: Annual total BVOC emissions in China for 2020 was 15.66 Tg and emissions from varied growth forms had different compositionsBVOC emission inventory simulated by the developed high‐resolution vegetation distribution (HRVD) data set had better accuracyBVOC emission enhanced at a rate of 72.06 Gg yr−1 during 2001–2020 caused by land cover change, mainly driven by changing leaf area index [ABSTRACT FROM AUTHOR]

With 263 reservoir pond wetlands in Erhai Lake Basin as the research object, this study discussed the purification effects of reservoir pood wetlands on nitrogen, phosphorus and organic matter, and the influence of vegetation distribution on the purification effect of reservoir wetlands. The results showed that the removal rates of TN and TP in farmland tail water, sewage tail water and river ectopic purification pond wetland were higher than that of COD, and the removal rates of TN, and TP in three functional types of reservoir pond wetlands were higher than that of COD. The purification effect of TP and COD in dry season were higher than that in rainy season. The vegetation types of reservoir pond wetland was single, and the emergent vegetation was the main vegetation. More than 70% of the reservoir pond wetland emergent vegetation coverage ranged from 25% to 75%. Invasive vegetation was widely distributed, with a total coverage of more than 11%. The number of species and coverage were positively correlated with the purification effect, and the effect of species and coverage on TP were greater than that of TN. The effect of vegetation coverage on TN and TP removal rate were greater than the number of species. [ABSTRACT FROM AUTHOR]

Background Natural forest resources in northwestern Ethiopia are currently under threat, requiring immediate conservation measures and a management strategy. Thus, an understanding of the present floristic diversity status is required. There is lack of such type of studies specific to fragmented forest patches and across environmental factors. Consequently, this study aimed to examine the existing state of these resources to apply sustainable forest management practices. Methods To achieve this, transects with 200 square plots measuring 400 m 2 were set up at nine forest patches with 200m spacing between plots and transects. Vegetation and environmental data were collected and analyzed using R version 4.1. Results Significant variations (p 0.008) were found in vegetation features along the slope, forest patches, and agroclimatic zone. When compared to other forest patches, highland, and mid-altitude forest patches had the highest species diversity (2.48) and stocking (2578 trees/ha). The gentle slope has the most species diversity (2.83). The species similarity between highland and mid-altitude forest habitats was found significant (69%). The vegetation cover in the mid-altitude forest patches was also high (abundance: 5-12%). In all the forest patches examined, tree life forms exceeded shrubs, climbers, and herbs. Conclusions According to the study’s findings, the state of forest resources varies considerably across different environmental variations. Despite the impression of entire forest patches from the outside, the interiors are open, with only huge and mature trees covering the canopy. This state has been triggered by deforestation, degradation, and inappropriate human and grazing operations.

The interaction between vegetation, sediment, and water flow creates various fluvial landscapes. Hydrological conditions and flood disturbances, as well as the habitat preference of vegetation, regulate its spatial distribution. To describe the spatial distribution of vegetation cover, here, we focus on vegetation distributions along river transverse transects that define vertical and horizontal distances from water areas during low flow periods. As one of the most dynamic river types, braided rivers can be significantly influenced by vegetation encroachment. However, the effects of vegetation distributions along river transects on braided river morphology remain unknown. To study the potential influence of vegetation distribution along river transects, a depth-averaged, hydro-morphodynamic model was employed. Using the model, we investigated a medium-sized, braided river with a gravel bed affected by riparian vegetation. The following scenarios of vegetation transect distributions were examined: (1) vegetation established near or covering the low water channel, and (2) vegetation established on bar tops and kept at a distance from the low water channel. The model successfully reproduced a reduction in the braiding index for a vegetated braided river. Depending on the transect distribution scenarios employed, significantly different effects for river morphology were obtained. For example, compared to vegetation on bar tops, vegetation located near the low water channel played a more critical role for changing river morphology, redirecting water flow, and changing the statistical characteristics of the riverbed elevation distribution. Vegetation near the low water channel not only concentrated water flow to low water channels but also redirected flow to the high elevation area by reducing low water channel flow capacity. The revealed effects of the vegetation transect distribution on river morphology development helped to determine effective management protocols for reducing the negative impact of vegetation encroachment. [ABSTRACT FROM AUTHOR]

The average temperature of the Korean Peninsula over the past 30 years has risen 1.4°C compared to the early 20th century (1912-1941), exceeding the global temperature increase trend. Vegetation responds very sensitively to climate change. Changes in phenological response, such as fall fliage, fruiting time of vascular plants, and appearance of insects, have occurred. Areas around Wando Arboretum, the target area of this study, belongs to the subtropical climate zone. In this study, we aimed to provide basic data for systematic management of biological resources through out the survey of vegetation distribution in the area around Wando Arboretum where warm-temperate plants distribute, using hyperspectral imaging-LiDAR. As a result of converting the classification images of individual information using hyperspectral images and Lidar into objects by vegetation correlation, a total of 27 classifications were confirmed with 18 families, 24 species, and three varieties. In addition, a total of 29,884 individuals were identified.

The study of modern pollen, and vegetation can improve the accuracy of paleoenvironmental reconstruction based on fossil pollen data. A total of 188 pollen surface samples were collected from Southern Xinjiang (34°00′–43°00′N, 74°00′–94°00′E) in China, with an elevation range of 888–1530 m. Surface pollen and vegetation were studied in the northern region of the Kunlun Mountains and the southern region of the Tianshan Mountains. The results showed that the surface pollen assemblages on the southern slope of the Tianshan Mountains (3530–1124 m) were divided into three pollen zones, namely, montane steppe, montane desert steppe, and montane desert. These zones were dominated by Artemisia, Chenopodiaceae, and Ephedra pollen. The surface pollen assemblages in the eastern Pamir Plateau (4530–1287 m) could be divided into alpine meadow, montane desert steppe, and montane desert zones, which were predominantly characterized by Artemisia, Chenopodiaceae, and Asteraceae pollen. However, the Southern Tarim Basin (3548–888 m) comprised montane desert steppe and montane desert zones, which was dominated by Artemisia and Chenopodiaceae pollen. The geographic distribution of the surface pollen sites obtained using ArcGIS, the R-value, and Pearson correlation analyses indicated that the over-represented Picea and Pinus pollen were of external origin and were transported by wind, water (rivers), and ice (glacier movement). Over-representation of Ephedra and Nitraria pollen was mainly distributed in the montane desert and desert steppe zones, respectively. Pollen from Chenopodiaceae and Artemisia were over-represented and broadly distributed across Southern Xinjiang. Juglans pollen was concentrated in areas with walnut trees, strongly indicating the presence of local parent plants. According to the Hybrid Single-particle Lagrangian Integrated Trajectory model, more Pinus pollen was transported to the Pamir region by external airflows during spring and summer, resulting in its higher surface pollen content. Research elucidating the relationship between modern pollen and vegetation in southern Xinjiang could provide data describing the surface palynological database of Xinjiang for use in large-scale paleoenvironmental reconstructions. [ABSTRACT FROM AUTHOR]

Studying the interactions between humans, land‐cover and biodiversity is necessary for the sustainable management of socio‐ecosystems and requires long‐term reconstructions of past landscapes, improving the integration of slow processes. The main source of information on past vegetation is fossil pollen, but pollen data are biased by inter‐taxonomic differential production and dispersal. The landscape reconstruction algorithm (LRA) approach is the most widely used to correct for these biases. The LOVE algorithm (LOcal Vegetation estimates), the second step in the LRA approach, also estimates the spatial extent of the local vegetation reconstruction zone (the relevant source area of pollen, RSAP). While LRA estimates have already been integrated into certain past land‐cover mapping approaches, none have been designed to allow the diachronic reconstruction of a land‐cover mosaic over the long term combining the following points: the direct integration of LOVE estimates as a source of variability in the composition and distribution of pollen taxa, without multiple scenarios, and the integration of spatiotemporal autocorrelation in the taxa distribution between periods. Here, we propose an innovative approach for BACKward LAND‐cover reconstruction (BACKLAND), combining these points and estimating the past land‐cover mosaic within a set of RSAPs. Based on three stages using parsimonious assumptions and easy‐to‐implement probabilistic and statistical tools, this approach requires LOVE estimates of sites close enough to each other for their RSAPs to overlap, botanical data, a digital elevation model and two recent land‐cover maps. Developed and tested on a small study area within the mountain landscape of the Bassiès valley (French Pyrenees), BACKLAND achieved the reconstruction of a past land‐cover map representing eight land‐cover types at a spatial resolution of 20 m with a good level of accuracy. We show in this study the originality of this approach and discuss its potential for palaeoenvironmental studies, historical ecology and the management of socio‐ecosystems. [ABSTRACT FROM AUTHOR]

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This study analyzed the trends and changes in climate-sensitive plants based on environmental attributes, using on-site survey data collected between 2006 and 2018. In combination with environmental attributes, 16 plant species were chosen as climate-sensitive biological indicator species and were spatially distributed based on national ecological survey data. With the use of regression methods and locally weighted scatterplot smoothing, possible changes in the vegetation distribution trends were simulated. The findings indicated that annual rainfall and temperature are critical environmental attributes, as they mostly affect the plant ecosystem. The simulated results suggest that plant habitats for the selected 16 individual species tend to be found in higher temperature zones, with a few exceptions. However, there was no clear pattern of the effects of annual rainfall on climate-sensitive plant species. The effects of climate change on these species are a risk to the environment; however, depending on the situation, adequate adaptation and management plans could provide opportunities for policy makers to make evidence-based decisions. [ABSTRACT FROM AUTHOR]

Among numerous vegetation studies, there are few studies on the elevation gradient distribution control mechanism and horizontal law of small-scale vegetation. In the same climate zone, topography is one of the most important factors affecting vegetation pattern. Here, we used the geo-informatic Tupu theory to construct topographic gradient-vegetation distribution information Tupu (TG-VDI Tupu) to display the topographical differentiation characteristics of vegetation. Moreover, an improved evaluation of topographical differentiation characteristics of vegetation was proposed based on topographic gradients, and the topographic composite index (TCI) was constructed to analyse the topographic variation in vegetation distribution. Meanwhile, the dominant factors and limiting factors affecting vegetation distribution under different topographic gradients were determined through statistical analysis. Combined with field surveys, Gaofen-1 (GF-1) satellite images were used to extract vegetation types, and the solar radiation value (SRV), topographic wetness index (TWI) and topographic variables were extracted from DEM data. The results indicate that TG-VDI Tupu can visually display topographic differentiation characteristics of vegetation on an elevation gradient. Elevation controls the horizontal distribution of vegetation on a small scale by changing ecological factors. At the same elevation, slope affects vegetation distribution by changing the SRV and TWI, while aspect changes the TWI. Coniferous forest is separated along a slope gradient and is more abundant on steep slopes. The percentage of broadleaf forest is negatively correlated with SRV and positively correlated with TWI, and the proportion is higher on the leeward slope facing north. The distribution of shrubs is more abundant on more xeric aspects and on steeper and more xeric slope configurations. In alpine areas above 2800 m, the abundance of vegetation types declines. This decline may be related to the weak solar radiation and widespread glacial landforms, exposed rocks and strong weathering. The methodology in our study can be applied to other regions and is expected to provide useful information for ecological conservation policy making.

The interaction between geomorphological and ecological processes plays a significant role in determining landscape patterns in glacier forelands. However, the spatial organization of this biogeomorphic mosaic remains unclear due to limited catchment-scale data. To address this gap, we used a multi-proxy analysis to map potential geomorphic activity related to surface changes induced by sediment transport on drift-mantled slopes and a glaciofluvial plain. High-resolution vegetation data were used to generate a catchment-scale map delineating vegetation cover and stability thresholds. The two maps were integrated, and an exploratory regression analysis was conducted to investigate the influence of geomorphic activity on vegetation colonization. The multi-proxy analysis resulted in an accurate mapping of catchment-wide geomorphic activity, with a validation accuracy ranging from 75.3% through field mapping to 85.9% through plot sampling. Through vegetation cover mapping, we identified biogeomorphic stability thresholds, revealing a mosaic of vegetation distribution. Distinct colonization patterns emerged across different geomorphic process groups, influenced by process magnitude and the time since the last disturbance event. The exploratory regression analysis showed that vegetation distribution is significantly affected by geomorphic processes. Based on the overlay of results regarding geomorphic activity and vegetation distribution, we suggest an age-independent framework that indicates four potential situations of biogeomorphic succession.

Under global warming, seasonal snow takes faster melting rate than before, which greatly changes the hydrological cycle. In this study, by targeting three typical seasonal snow-covered land types (i.e., open shrubland, evergreen needleleaf forest and mixed forest) in the Northern Hemisphere, the start of growing season (SGS) has been found obviously advanced in the past years, greatly contributed by the faster melting rate of seasonal snow. It is manifested that significantly positive correlation has been found between SGS and May snow depth for open shrubs, March and April snow depth for evergreen needleleaf forests and March snow depth for mixed forests. However, such close association is not appeared in all the climate conditions of same vegetation. In the future, as the rate of melting snow becomes faster in the high emission of greenhouse gasses than the current situation, continuously advanced SGS will accelerate the change of vegetation distribution in the Northern Hemisphere. These findings offer insights into understanding the effect from seasonal snow on vegetation and promote the sustainable utilization of regional vegetation in the Northern Hemisphere.

Predicting vegetation distribution strengthens ecosystem management, protection, and restoration in arid and degraded areas. However, data quality and incomplete data coverage limit prediction accuracy for Picea crassifolia Kom. (Qinghai spruce) forest in the Qilian Mountains of China. Here, we used a logistic regression model combined with high-resolution vegetation distribution data for different sampling scales and digital elevation models (DEMs) to determine the potential distribution of P. crassifolia forest in the Dayekou catchment in the Qilian Mountains. We found that the model with the best simulation accuracy was based on data with a DEM scale of 30 m and a sampling accuracy of 90 m (Nagelkerke's R2 = 0.48 and total prediction accuracy = 83.89%). The main factors affecting the distribution of P. crassifolia forest were elevation and potential solar radiation. We conclude that it is feasible to calculate the distribution of arid mountain forests based on terrain and that terrain data at 30 m spatial resolution can fully support the simulation of P. crassifolia forest distribution. [ABSTRACT FROM AUTHOR]

Vegetation shifts can directly alter habitat dynamics and indirectly impact habitat stability relative to disturbance response. Barrier island dune habitats exhibit spatiotemporally dynamic topography that is affected by vegetation. However, vegetation distribution data can be rare and vegetation persistence is largely unknown such that species turnover over in communities can occur unnoticed. This is true despite concerns and documented cases of woody encroachment related to climate change in these ecogeomorphic habitats where physical stability to resist storm erosion varies with vegetation distribution and density. In 1956 and 1957, the vegetation of Island Beach State Park, NJ, was mapped as a permanent record for subsequent ecological study. In June 2020, we remapped the vegetation of 5.4 of 17 km north to south, seaward of the thicket community boundary. We maintained the same classification system as the historic record, physically mapping vegetation patches via GPS. We quantified changes in thicket, heather, and grass community distribution between the two time periods. Habitat persistence and conversion varied in the 63 years. Heath communities saw 80%–97% habitat loss in conversion to woody thicket. Conversely, thicket community distribution drastically increased, replacing heath where it was previously prevalent. This represents the first known documented instances of woody encroachment for Morella pensylvanica. When they did not expand, thicket communities receded landward or underwent turnover to an invasive species. Woody species of interest for dune stabilization occupied areas of similar habitat characteristics. Dune vegetation distribution persistence from 1957 to 2020 was relatively consistent and stable with the exception of heath habitat conversion. Barrier island stability is directly related to vegetation stability such that understanding where community shifts might occur over time can aid in managing and modeling efforts surrounding these dynamic ecogeomorphic habitats. [ABSTRACT FROM AUTHOR]

Plastic pollution poses a serious threat to marine ecosystems; yet quantifying the mass concentrations of nano- and microplastics (NMPs) in saltmarsh sediments at the ocean-land interface remains a critical research gap. Here, the study employed reliable and efficient analytical techniques, namely pressurized liquid extraction and the double-shot model of thermal desorption/pyrolysis-gas chromatography-mass spectrometry, to quantify six different types of NMPs in the sediment of a multi-species saltmarsh, providing the first comprehensive assessment of NMP mass concentration and burial in this saltmarsh environment. The results demonstrate that polyethylene, polyvinyl chloride, and polypropylene dominated the NMP composition in sediments, constituting 72.6%, 17.3%, and 4.5% of the total NMPs, respectively. The measured NMPs represent an anthropogenic intrusion, constituting 0.10%-0.23% of the carbon storage in the saltmarsh. By examining the vertical concentration profiles, this study unveiled the influence of saltmarsh vegetation on NMP deposition in sediments, establishing a connection with local sedimentation patterns and the historical zonation of plant species such as Scirpus mariqueter, Phragmites australis and Spartina alterniflora. These findings underscore the crucial role of saltmarsh vegetation in facilitating NMP settling and retention, highlighting the necessity of considering vegetation dynamics in examining the emerging NMP pollution in coastal wetlands., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Exploring alpine vegetation dynamics and its driving factors help to predict changes in hydrothermal circulations at high elevations in the future. Currently, there is a lack of systematic research on this topic in the permafrost regions at a basin scale. Spatiotemporal variations of vegetation pattern and growth estimated from satellite remote sensing images at a 30 m spatial resolution on the Google Earth Engine cloud platform were investigated in the Shule River headwater region from 2000 to 2021. The results showed shrinking trends in alpine grassland (AG) and wetland (AW) area, while an expanding trend in alpine desert (AD) area. AD moved to lower altitudes and occupied AG and AW area, possibly owing to mountain permafrost degradation and extreme precipitation. Vegetation patches became fragmented and complex, reflected by increases in patch number and shape index. Vegetation growth, as approximated by the normalized difference vegetation index (NDVI), increased significantly in 42 % of the vegetated area (p

Terrestrial ecosystems are an important part of Earth systems, and they are undergoing remarkable changes in response to global warming. This study investigates the response of the terrestrial vegetation distribution and carbon fluxes to global warming by using the new dynamic global vegetation model in the second version of the Chinese Academy of Sciences (CAS) Earth System Model (CAS-ESM2). We conducted two sets of simulations, a present-day simulation and a future simulation, which were forced by the present-day climate during 1981–2000 and the future climate during 2081–2100, respectively, as derived from RCP8.5 outputs in CMIP5. CO2 concentration is kept constant in all simulations to isolate CO2-fertilization effects. The results show an overall increase in vegetation coverage in response to global warming, which is the net result of the greening in the mid-high latitudes and the browning in the tropics. The results also show an enhancement in carbon fluxes in response to global warming, including gross primary productivity, net primary productivity, and autotrophic respiration. We found that the changes in vegetation coverage were significantly correlated with changes in surface air temperature, reflecting the dominant role of temperature, while the changes in carbon fluxes were caused by the combined effects of leaf area index, temperature, and precipitation. This study applies the CAS-ESM2 to investigate the response of terrestrial ecosystems to climate warming. Even though the interpretation of the results is limited by isolating CO2-fertilization effects, this application is still beneficial for adding to our understanding of vegetation processes and to further improve upon model parameterizations. [ABSTRACT FROM AUTHOR]

The global distribution of vegetation is largely determined by climatic conditions and feeds back into the climate system. To predict future vegetation changes in response to climate change, it is crucial to identify and understand key patterns and processes that couple vegetation and climate. Dynamic global vegetation models (DGVMs) have been widely applied to describe the distribution of vegetation types and their future dynamics in response to climate change. As a process‐based approach, it partly relies on hard‐coded climate thresholds to constrain the distribution of vegetation. What thresholds to implement in DGVMs and how to replace them with more process‐based descriptions remain among the major challenges. In this study, we employ machine learning using decision trees to extract large‐scale relationships between the global distribution of vegetation and climatic characteristics from remotely sensed vegetation and climate data. We analyse how the dominant vegetation types are linked to climate extremes as compared to seasonally or annually averaged climatic conditions. The results show that climate extremes allow us to describe the distribution and eco‐climatological space of the vegetation types more accurately than the averaged climate variables, especially those types which occupy small territories in a relatively homogeneous ecological space. Future predicted vegetation changes using both climate extremes and averaged climate variables are less prominent than that predicted by averaged climate variables and are in better agreement with those of DGVMs, further indicating the importance of climate extremes in determining geographic distributions of different vegetation types. We found that the temperature thresholds for vegetation types (e.g. grass and open shrubland) in cold environments vary with moisture conditions. The coldest daily maximum temperature (extreme cold day) is particularly important for separating many different vegetation types. These findings highlight the need for a more explicit representation of the impacts of climate extremes on vegetation in DGVMs. [ABSTRACT FROM AUTHOR]

In this paper, based on the finite volume method, a high-precision hydrodynamic model coupled with the habitat suitability model is established, and the computational efficiency of the coupled model is improved by a graphics processing unit (GPU)-accelerated technology. The coupled model is used to solve the problem of the non-conservation of mass that may be caused by the nearshore hydrodynamic model in the processing of wetting and drying, while avoiding the unphysical high velocities at the wetting and drying boundaries. The coupled model is applied to simulate the high-precision hydrodynamic process of the Liao River estuary (LRE) and the hydrological habitat suitability of the estuarine vegetation (Suaeda heteroptera) growing in the LRE. The simulated values of the hydrological variables (the water level, the water depth, the current velocity and direction) are highly consistent with the measured values. The root mean square errors (RMSE) of the hydrological variables are 0.10m, 0.12m/s and 17.24°, respectively. Furthermore, the simulated combined suitability index (CSI) distribution of Suaeda heteroptera (S. heteroptera) matches with the distribution of S. heteroptera obtained from the high-resolution remote sensing satellite images during the same time period. The ratio of the simulated weighted usable area (WUA) of S. heteroptera to the area obtained from the remote sensing satellite images during the same period is 81.9%. This study reveals the phenomenon that the distribution of S. heteroptera in the LRE is highly correlated with the high-precision hydrodynamic processes, and provides a scientific basis and a valuable reference for the conservation and the restoration of the estuarine vegetation. [ABSTRACT FROM AUTHOR]

Evaluation of vegetation structure and distribution simulations in Earth system models (ESMs) is the basis for understanding historical reconstruction and future projection of changes in terrestrial ecosystems, carbon cycle, and climate based on these ESMs. Such assessments can also provide important information of models’ merits and shortcomings or systematic biases, and so clues for model development. Vegetation structure and distribution in ESMs are primarily characterized by three variables: leaf area index (LAI), tree height, and fractional coverage of plant functional type (PFT). However, for the ongoing Coupled Model Intercomparison Project Phase 6 (CMIP6), only temporal variabilities of global-averaged LAI time series were evaluated, others remain largely uninvestigated. This study systematically investigates the spatial and/or temporal variability of the three critical variables from 27 ESMs in CMIP6 using satellite observations. Our results show that all models and the multi-model ensemble mean (MME) can generally reproduce the observed LAI spatial pattern but all of them overestimate the global mean LAI mainly due to overestimation of LAI in non-forested vegetated areas. Most CMIP6 models fail to capture the temporal variability in the annual LAI because of large biases in both the simulated trend magnitude and temporal pattern of interannual variability. The average LAI seasonal cycles in different latitude zones are roughly reproduced by the models, but 1–2 months delays in the LAI peak appear in the Arctic-boreal zone. Additionally, CMIP6 models overall overestimate tree height, and largely overestimate the global grass area but underestimate tree and shrub areas, especially in the middle and high latitudes. It should be kept in mind that such biases may have further impacts on the simulations of the related carbon and land–atmosphere interaction variables (e.g., ecosystem production, carbon storage, transpiration, and temperature) for global change research. Hence, bias-correction should be made to improve reliability of vegetation structure and distribution when future projections and historical reconstructions. They also underscore the urgent need in development and parameterization of dynamic vegetation within Earth system models, such as phenology, allocation, and morphology schemes.

The impacts of climate change and human activities on vegetation dynamics have attracted wide attention, especially in sensitive and vulnerable areas such as the Qingzang Plateau of China. In this region, a series of ecological restoration projects have been launched while the effectiveness of these projects requires evaluation and further improvements. Remote sensing with high temporal resolution and spatial coverage is an effective way for the vegetation dynamics research in this region. In this study, the spatial and temporal distribution of climate factors and vegetation coverage as well as the influencing factors such as air temperature, precipitation, land use, slope, slope direction, soil and altitude were analyzed. The geographical detector was used to analyze the influence of climate factors on vegetation coverage and the interaction among factors in different eco-geographical regions. The results showed that: 1) the average values from the 20 years of normalized difference vegetation index (NDVI) decreased gradually from southeast (> 0.61) to northwest (0.12). The overall average of NDVI increased 0.02 per year from 1998 to 2018 and the impact factors varied among different eco-geographical regions; 2) some controlling factors showed nonlinear enhancement such as altitude and slope; 3) land use was an important factor affecting the distribution of vegetation especially in humid, semi-arid and arid areas, but the impacts of elevation and temperature were stronger than land use types in semi-humid and humid areas. The design and construction of ecological protection and restoration projects on the Qingzang Plateau required scientific and detailed demonstration as well as monitoring and evaluation. In addition, new tools and theories were also needed in the selection of ecosystem restoration strategies. Based on the findings, this study also provides suggestions for the sustainable ecological restoration on the Qingzang Plateau.

The influences of different emergent and rigid vegetation distributions on hydrodynamic characteristics in a 180° curved open channel are experimentally investigated in this study. Experimental results show that the transverse velocity gradient generated at the vegetation and non-vegetation interface is greater for the vegetation presence on the convex bank (inner case) than the vegetation on the concave bank (outer case) with the effect of centrifugal force pointing to the concave bank. The presence of uniform distributed vegetation will weaken the secondary flow, and theoretical analysis is also developed to indicate the influential range of emergent vegetation on secondary flow over a curved channel. In addition, the peak frequency determined from the spectrum at the vegetation and non-vegetation interface along a curved channel is still associated with the Kelvin–Helmholtz (K-H) instability. Both the curved channel and presence of emergent vegetation can reduce the occurrence frequency of turbulent ejection and sweep events. [ABSTRACT FROM AUTHOR]

The distribution of alpine vegetation is highly sensitive to climate change, which attracted the attention of climate scientists as well as ecologists. However, the dominant factors of vegetation distribution showed greatly spatiotemporal variation, especially the alpine grasslands on the Tibetan Plateau, which is known as an amplifier of climate warming. In this study, to identify the dominant factors of vegetation distribution, we verified the reliability and accuracy of the classification of alpine steppe and alpine meadow by Random Forest and tried to provide a new reference for the classification schemes. Dataset collected from the field investigations (200 sites) and previous publications(200 sites) were used in this study for model calibration and validation. Then climate models of CMIP6 were used to forecast the underlying transfers and changes of vegetation boundary in the future. Our results revealed that precipitation may be the dominant driver in the alpine grassland distribution, with the highest relative importance of 41.26%. Through different climate scenarios from 2000 to 2100, the vegetation boundary showed a shift from northeast to southwest. Within the SSP5-8.5 scenario it moves from 94.50° to 93.49° and shifted from north to south by 0.34°. Our results demonstrated the significant role of precipitation in the alpine grassland distribution and revealed the migration of the alpine grassland ecosystem under different climate change scenarios. Our work may be useful to deal with global climate change, early warning, and grassland protection, as well as adaptive management of grassland.

Hydrologic processes in tidal wetlands are important regulators controlling the growth and productivity of salt marsh plants. Understanding hydrodynamic and hydrological processes is therefore critical to sustaining ecosystem functions and productivity in tidal wetlands. We used remote sensing and geographic information system to determine the spatial distributions of Suaeda heteroptera and Phragmites australis plants on the tidal-flats of Liao River Estuary (LRE), China. Next, hydrodynamic modelling was performed to characterize the water levels and tidal currents in these wetland waters. After extensive calibration and validation against field data, we proposed a 2D circulation structure for the LRE that can be used to calculate the hydrological parameters in different areas of the tidal wetlands. The simulation results showed that the hydrological characteristics of the tidal wetlands were primarily dependent on local topography and water level. The prevalent plant community in the LRE, dominated by Suaeda heteroptera, was abundant across a large range of flood times (0.79 ~ 3.22 h/day), inundation frequencies (11 ~ 52 times/month), and max flooding depths (0.42 ~ 0.81 m). However, certain hydrological conditions did appear to limit the spatial distributions of wetland plant communities. These findings have provided detailed methods of a novel approach to quantitatively assess habitat status in tidal-flat wetlands. [ABSTRACT FROM AUTHOR]

We use remote sensing data, GIS, and spatial panel data regression to analyze the carbon sequestration capacity of different regions in China caused by climate and vegetation distribution. The results showed that (1) climate, soil types, and human activities significantly influenced vegetation distribution. Regional vegetation distribution is highly correlated with carbon sequestration intensity. (2) Ecological projects such as the "Three North Shelterbelts" increased the carbon sequestration in relevant regions, while the urbanization reduced the forestland and the carbon sequestration capacity. (3) For every 10,000 hectares of forestland, farmland, wetland, and grassland, the corresponding annual CO2 sequestration was 0.1854, 0.0795, 0.0623, and 0.0045 million tons, respectively. (4) The increase of 0.1 °C in average temperature, 1% in air humidity, 1 h in sunshine duration, 1 million tons in CO2 emissions could increase the annual carbon sequestration by −0.314, 1.0721, 0.0239, and 0.0857 million tons in China, respectively. [ABSTRACT FROM AUTHOR]

Desert pavements (DPs) are critical for maintaining ecological stability and promoting near‐surface hydrological cycling in arid regions. However, few studies have focused on eco‐hydrological processes of DPs in the ecological systems of fluvial fans. Although DP surfaces appear to be barren and flat, we found that the surfaces are characterized by surface mosaic patterns of desert pavement (mosaic DP) and bare ground (mosaic BG). We investigated the effects of mosaic DP on water infiltration and vegetation distribution at six sites in fluvial fans (one on a hillside and five within the sectors of fans) along a southwest belt transect in northern Linze County, in the central Hexi Corridor (China). We found significant differences in mosaic DP between the hillside and sector sites in terms of pavement thickness and vesicular horizon thickness (Av thickness), particle composition, and bulk density, although significant differences were absent for mass soil water content, gravel coverage, and surface gravel size. The mosaic DP inhibited water infiltration by the pavement layer, where the sorptivity (S), initial infiltration rate (iint), steady‐state infiltration rate (isat) and infiltration time (T) averaged 1.19 cm/min‐0.5, 0.64 cm/min, 0.13 cm/min and 12.76 min, respectively. Where the pavement layer was scalped, the S, iint, and isat increased by 0.27 cm/min‐0.5, 0.52 cm/min, and 0.40 cm/min, respectively, and the T reduced by 7.42 min. Water infiltration was mainly controlled by the pavement layer thickness (+), Av thickness (−), surface gravel coverage (−), fine earth (+) and fine gravel (−) in the pavement layer. The DP surfaces only had a sparse covering of shrubs, but an abundance of herbs. Few shrubs were present on the mosaic DP, but a greater number of shrubs and herbs grew on the mosaic BG. It can be concluded that DPs can maintain vegetation stability for different surface mosaic patterns. This study deepens our understanding of the eco‐hydrological cycle of DP landscapes in arid regions. [ABSTRACT FROM AUTHOR]

• Topographic gradient-vegetation distribution information Tupu can visually display topographic differentiation characteristics of vegetation on the elevation gradient. • Topographic composite index was constructed to analyze topographic gradients-vegetation distribution relationship. • Different vegetation types have different dominant and limiting factors. • Provide useful information for ecological conservation policy making. Among numerous vegetation studies, there are few studies on the elevation gradient distribution control mechanism and horizontal law of small-scale vegetation. In the same climate zone, topography is one of the most important factors affecting vegetation pattern. Here, we used the geo-informatic Tupu theory to construct topographic gradient-vegetation distribution information Tupu (TG-VDI Tupu) to display the topographical differentiation characteristics of vegetation. Moreover, an improved evaluation of topographical differentiation characteristics of vegetation was proposed based on topographic gradients, and the topographic composite index (TCI) was constructed to analyse the topographic variation in vegetation distribution. Meanwhile, the dominant factors and limiting factors affecting vegetation distribution under different topographic gradients were determined through statistical analysis. Combined with field surveys, Gaofen-1 (GF-1) satellite images were used to extract vegetation types, and the solar radiation value (SRV), topographic wetness index (TWI) and topographic variables were extracted from DEM data. The results indicate that TG-VDI Tupu can visually display topographic differentiation characteristics of vegetation on an elevation gradient. Elevation controls the horizontal distribution of vegetation on a small scale by changing ecological factors. At the same elevation, slope affects vegetation distribution by changing the SRV and TWI, while aspect changes the TWI. Coniferous forest is separated along a slope gradient and is more abundant on steep slopes. The percentage of broadleaf forest is negatively correlated with SRV and positively correlated with TWI, and the proportion is higher on the leeward slope facing north. The distribution of shrubs is more abundant on more xeric aspects and on steeper and more xeric slope configurations. In alpine areas above 2800 m, the abundance of vegetation types declines. This decline may be related to the weak solar radiation and widespread glacial landforms, exposed rocks and strong weathering. The methodology in our study can be applied to other regions and is expected to provide useful information for ecological conservation policy making. [ABSTRACT FROM AUTHOR]

Despite paleochannels play a key role in the evolution of aeolian dune patterns, little attention has been paid on the interactions between paleochannels and aeolian processes. The objective of this article is to analyze the interactions between paleochannels and aeolian processes and their implications on the aeolian dune patterns. One site in the Kuruk Tagh Desert in eastern margin of the Tarim Basin, northwestern China is selected as the case study area. We analyze the sedimentary environment of the aeolian dunes around paleochannels based on the grain-size parameters. Furthermore, we present spatial and temporal dynamics of the vegetation and aeolian dunes around the paleochannels. The results indicate that: (1) ground water determines the spatial distribution of the vegetation and controls the evolution of aeolian dune patterns indirectly; (2) aeolian dunes around the paleochannels are initially controlled by fluvial and aeolian processes collectively. Then, the aeolian processes always play a dominant role after the drying up of these paleochannels; (3) the paleochannels in aeolian processes dominated areas ultimately evolve into a belt sand source due to the deposition of aeolian sediments and the encroachment of aeolian dunes. The timescale of the paleochannels’vanishment depends not only on the depth and width of the channels, but also on the angle between bedform orientation and prevailing sand flux direction.

Semi-arid floodplain vegetation is an essential component of floodplain and terrestrial ecosystems due to the wide range of services provided for waterbirds, woodland birds, amphibians and mammals, together with their contribution to natural carbon sequestration. Since overbank flooding has been considered the driving factor of vegetation distribution on floodplains, sustainable water resource management requires a better understanding of the influence of inundation on vegetation distribution. We examined the relationship between the distribution of four flood-dependant vegetation communities and associated long term inundation metrics on the upper Darling River floodplain using electivity analysis and a generalised additive model (GAM) by generating a total of 10,478 individual inundation maps with a high spatial resolution over a period of 29 years. Our results show that the four dominant vegetation communities are situated differently in relation to inundation attributes. The inundation metrics better explained the variation in the distribution of River Red Gum than those of Black box, Coolabah and Lignum communities. We found that the floodplain forests and woodlands in the upper Darling can survive longer periods of drought and shorter inundation duration than previously reported. The results provide practical information for ecosystem management by offering a means of predicting changes in vegetation distribution in relation to alteration in flow regime resulting from water planning arrangements or climate change.

The dynamic responses of wetlands to upstream water conservancy projects are becoming increasingly crucial for watershed management. Poyang Lake is a dynamic wetland system of critical ecological importance and connected with the Yangtze river. However, in the context of disturbed water regime in Poyang Lake resulting from human activities and climate change, the responses of vegetation dynamics to the Three Gorges Dam (TGD) have not been investigated. We addressed this knowledge gap by using daily water level data and Landsat images from 1987 to 2018. Landsat images were acquired between October and December to ensure similar phenological conditions. Object‐oriented Artificial Neural Network Regression for wetland classification was developed based on abundant training and validation samples. Interactions between vegetation coverage and water regimes pre and post the operation of the TGD were compared using classification and regression trees and the random forest model. Since the implementation of the TGD in 2003, Poyang Lake has become drier, especially during the dry season. A more rapid plant growth rate was observed post TGD (44.74 km2 year−1) compared to that of the entire study period (12.9 km2 year−1). Average water level for the antecedent 20 days most significantly affected vegetation before 2003, whereas average water level for the antecedent 5 or 10 days was more important after 2003. The impoundment of the TGD after the flood season accelerated the drawdown processes of Poyang Lake, and the rapidly exposed wetlands accelerated vegetation expansion during the dry seasons, resulting in shrinkage and degradation of the lake area. This study deepens our knowledge of the influences of newly developed dams on lakes and rivers. [ABSTRACT FROM AUTHOR]

Compacted soil has an adverse effect on plant roots and affects water and nutrient availability. However, different degrees of soil compaction may be suitable for growth and development of different understory species. This study determined whether soil compaction could explain characteristics of 10 different Dahurian larch (Larix gmelinii Rupr.) forest types in the Daxing'anling area. The relationship of soil compaction to soil depth was also studied. Forty-five tests were conducted on soil compaction of the 10 forest types with multiple comparisons, of which five showed no significant differences. At different soil depths, there were significant differences in soil compaction among forest types. The correlation between the degree of soil compaction and depth was positive and significant. The Larix gmelinii—shrub forest type, L. gmelinii—herb forest type, and L. gmelinii—swamp forest type were significantly different in soil compaction according to soil depth. This research indicates that, as a physical property, soil compaction may be used to explain forest distribution spatial variabilities. [ABSTRACT FROM AUTHOR]

Although leaf area index (LAI) is one of the essential parameters employed to monitor global vegetation, no global LAI products which use a fine spatial resolution yet exist. To remedy this, we herein outline an adapted LAI retrieval algorithm which employs HuanJing-1 charge-coupled device (HJ-1 CCD) data, which was originally determined using Landsat thematic mapper (TM) data. Validation of this adapted LAI retrieval algorithm via field measurements demonstrates that errors for ∼72% of the sample sites were within a range of 0.2 for the Bashang Grassland in Hebei Province, and within 1.0 for the Taihe region in Jiangxi Province. In addition, the correlation coefficients (R) of HJ-1 LAI and ground-measured LAI data were similar to those of MODIS LAI and ground-measured LAI datasets for both regions. These results demonstrate the potential for transposing a mature Landsat LAI-retrieval algorithm to HJ-1 data. Furthermore, we generated 30 m HJ-1 LAI datasets for China for the summer of 2012. An analytical comparison between retrieved HJ-1 LAI and MODIS LAI data showed the coherence of the LAI distribution. Finally, a specific post-forest fire area was mapped using HJ-1 LAI datasets.

Despite paleochannels play a key role in the evolution of aeolian dune patterns, little attention has been paid on the interactions between paleochannels and aeolian processes. The objective of this article is to analyze the interactions between paleochannels and aeolian processes and their implications on the aeolian dune patterns. One site in the Kuruk Tagh Desert in eastern margin of the Tarim Basin, northwestern China is selected as the case study area. We analyze the sedimentary environment of the aeolian dunes around paleochannels based on the grain-size parameters. Furthermore, we present spatial and temporal dynamics of the vegetation and aeolian dunes around the paleochannels. The results indicate that: (1) ground water determines the spatial distribution of the vegetation and controls the evolution of aeolian dune patterns indirectly; (2) aeolian dunes around the paleochannels are initially controlled by fluvial and aeolian processes collectively. Then, the aeolian processes always play a dominant role after the drying up of these paleochannels; (3) the paleochannels in aeolian processes dominated areas ultimately evolve into a belt sand source due to the deposition of aeolian sediments and the encroachment of aeolian dunes. The timescale of the paleochannels'vanishment depends not only on the depth and width of the channels, but also on the angle between bedform orientation and prevailing sand flux direction. [ABSTRACT FROM AUTHOR]

Poyang lake is the largest freshwater lake in China, possessing global ecological functions. Impact of soil characteristics on vegetation distribution is potentially important but is poorly understood in this typical vast water-passing lake wetland. To explore the relationships between soil properties and vegetation distribution, soil moisture, soil nutrients, species construction, diversity and biomass were measured monthly in two dominant vegetation communities, namely, the Artemisia selengensis community and the Carex cinerascens community. Canonical correspondence analysis (CCA) and spearmen correlation were performed to evaluate the relationships between vegetation characteristics and edaphic variables. Results showed great heterogeneity in the ecological characteristics of plants. There are positive relationships between soil nutrients and ecological characteristics of plants, especially the biomass and the maximum height of the dominant species. Cynodon dactylon and Artemisia selengensis were mainly distributed in the upland with lower nutrient concentration and moisture content, whereas Cardamine lyrate, Triarrhena Lutarioriparia and Carex cinerascens were mainly found near the lake shore where the moisture and nutrients accumulated, demonstrating a legible zonal distribution along the edaphic gradient. The findings have provided an extension to the existing literatures, improving the understanding of the potentially crucial edaphic effects on vegetation in Poyang lake wetlands. [ABSTRACT FROM AUTHOR]

Premise of research. The soil seed bank (SSB) plays a critical role in vegetation regeneration after stress and/or disturbance events. Here, we analyzed how drought and grazing influence the SSB of shrub patches and interpatches in a rangeland from northern Patagonia. Methodology. Soil samples were collected from shrub patches and interpatches on heavily grazed, moderately grazed, and ungrazed sites at the end of a multiyear drought and 2 yr after the end of the drought. Sampling was done immediately before seed dispersion of the dominant species in order to study the persistent seed bank. Seeds were separated from the mineral soil by elutriation and grouped into four life-forms: annual grasses, perennial grasses, forbs, and shrubs. Pivotal results. In all sampling conditions, the SSB was markedly dominated by forbs. Total seed density and seed density of every life-form were higher in shrub patches than in interpatches. Seed density of grasses and shrubs was not influenced by drought and grazing in both shrub patches and interpatches. In contrast, seed density of forbs was negatively influenced by drought in interpatches and positively influenced by grazing in shrub patches. Conclusions. The results suggest that in patchy rangelands of northern Patagonia the SSB of shrub patches is less severely depleted than that of interpatches during multiyear droughts, particularly for forbs under high grazing intensity. However, the growth of the SSB after drought is a slow process in both shrub patches and interpatches. Our results highlight the importance of grazing pressure alleviation during drought conditions to safeguard the SSB, which is the only source of seedling recruitment for most species in northern Patagonia rangelands. [ABSTRACT FROM AUTHOR]

In order to solve the uneven distribution of vegetation in mineral resources areas, a data mining method for vegetation distribution in mineral resources areas is proposed. The preparation and distribution of mineral areas follow the spatial distribution law. The longitude, latitude and elevation of ground control points are measured by RTK, and the UAV data images are obtained. The original aerial images are corrected by the precise coordinates of ground control points. Based on Orthophoto image of sample plot, decision tree algorithm is used to establish sample training data to obtain vegetation coverage grade of mineral resources. The theory of linear decomposition method is used to establish the corresponding linear mixed model, and the sample data is substituted into the linear element decomposition model to calculate the contribution rate of soil and vegetation coverage. The results show that the contribution rate of vegetation coverage in mineral resources areas is about 70%, and the vegetation coverage level is higher. [ABSTRACT FROM AUTHOR]

Earth System Models (ESMs) are essential tools for understanding and predicting global change, but they cannot explicitly resolve hillslope‐scale terrain structures that fundamentally organize water, energy, and biogeochemical stores and fluxes at subgrid scales. Here we bring together hydrologists, Critical Zone scientists, and ESM developers, to explore how hillslope structures may modulate ESM grid‐level water, energy, and biogeochemical fluxes. In contrast to the one‐dimensional (1‐D), 2‐ to 3‐m deep, and free‐draining soil hydrology in most ESM land models, we hypothesize that 3‐D, lateral ridge‐to‐valley flow through shallow and deep paths and insolation contrasts between sunny and shady slopes are the top two globally quantifiable organizers of water and energy (and vegetation) within an ESM grid cell. We hypothesize that these two processes are likely to impact ESM predictions where (and when) water and/or energy are limiting. We further hypothesize that, if implemented in ESM land models, these processes will increase simulated continental water storage and residence time, buffering terrestrial ecosystems against seasonal and interannual droughts. We explore efficient ways to capture these mechanisms in ESMs and identify critical knowledge gaps preventing us from scaling up hillslope to global processes. One such gap is our extremely limited knowledge of the subsurface, where water is stored (supporting vegetation) and released to stream baseflow (supporting aquatic ecosystems). We conclude with a set of organizing hypotheses and a call for global syntheses activities and model experiments to assess the impact of hillslope hydrology on global change predictions. Plain Language Summary: Hillslopes are key landscape features that organize water availability on land. Valley bottoms are wetter than hilltops, and sun‐facing slopes are warmer and drier than shaded ones. This hydrologic organization leads to systematic differences in soil and vegetation between valleys and hilltops, and between sunny and shady slopes. Although these patterns are fundamental to understanding the structures and functions of water and terrestrial ecosystems, they are too fine grained to be represented in global‐scale Earth System Models. Here we bring together Critical Zone scientists who study the interplay of vegetation, the porous upper layer of the continental crust from vegetation to bedrock, and moisture dynamics deep into the weathered bedrock underlying hillslopes and Earth System Model scientists who develop global models, to ask: Do hillslope‐scale processes matter to predicting global change? The answers will help scientists understand where and why hillslopes matter, and to better predict how terrestrial ecosystems, including societies, may affect and be affected by our rapidly changing planet. Key Points: Lateral flow from ridges to valleys, and contrasts between sunny and shady slopes organize water, energy and vegetation across landscapesThese processes may affect Earth System Model predictions of terrestrial water storage and fluxes, as well as ecosystem resilience to stressThe greatest knowledge gap is the subsurface structure; Critical Zone science can offer new insights into terrestrial water storage/fluxes [ABSTRACT FROM AUTHOR]

Water regime is regarded as the primary factor influencing the vegetation distribution in natural wetland ecosystems. However, the effect of water regime change induced by large-scale hydraulic engineering on vegetation distribution is still unclear. In this study, multi-temporal TM/ETM+/OLI images and hydrological data from 1995 to 2015 were used to elucidate how the change in water regime influenced the vegetation distribution in the East Dongting Lake (EDTL), especially after the operation of the Three Gorges Dam (TGD) in 2003. Using unsupervised and supervised classification methods, three types of land cover were identified in the study area: Water and Mudflat, Grass, and Reed and Forest. Results showed that the total vegetation area in EDTL increased by approximately 78 km2 during 1995–2015. The areas of Reed and Forest and Grass exhibited a contrasting trend, dramatic increase in Reed and Forest but sharp decrease in Grass, particularly after the operation of TGD. The lowest distribution elevations of Grass and Reed and Forest decreased by 0.61 and 0.52 m, respectively. As a result of water level variation, submergence duration increased at 20–21 m and 28 m elevations (1–13 days), but significantly decreased at 22–27 m and 29–30 m elevations (-3 to -31 days). The submergence duration of Grass and Reed and Forest was 246 and 177 days, respectively. This study indicated that wetland vegetation pattern significantly changed after the operation of TGD, mainly as a result of changes in submergence condition. Submergence duration might be an effective indicator to predict the shift of vegetation distribution in EDTL, and which could provide scientific guidance for vegetation restoration and wetland management in this lake.

Estuary protection is a fundamental part of watershed management. However, land reclamation activities affect species distribution patterns and cause ecological degradation. To improve watershed management, we studied the distribution patterns of three typical salt marsh species and their interspecific interactions along groundwater table depth and salinity gradients using an index of Field Box Dimension and a Relative Interaction Index. We also simulated the groundwater gradient after two typical land reclamation activities, sea reclamation and embanking, after ten years. Our results showed that sea reclamation will change the location of the groundwater salinity peak along a land-to-sea transect and that there is no salinity peak after embanking. Vegetation distribution patterns also differed, from a zonal pattern (in salt marsh) to a mosaic pattern (after embanking). The decrease in the salinity gradient of the non-core area is an important cause for the differences we found in vegetation patterns. [ABSTRACT FROM AUTHOR]

Aims: Establishing a vegetation-soil model in Mediterranean saltmarshes based on the relationships between the plant communities and the abiotic factors, considering temporary variation.Methods: Relationships between perennial plant species abundances and plant communities were analysed by DCAs. A CCA was performed to study the relationships between floristic composition and edaphic variables. Sixteen soil variables and Pearson correlations between them were considered. Marginal and conditional effects were supported by mixed ANOVA. Statistical analyses were performed to check temporary variation.Results: DCAs results showed eight vegetation types. CCA showed E.C. as the main gradient, with the succulent halophyte communities growing in high E.C. soils. SAR and percentage of sand were considered as secondary gradients. Finally, the highest values of the edaphic variables were observed, in general, during the cold period.Conclusions: The main gradient of salinity, together with sodicity and texture gradients, would markedly influence the plant distribution in Mediterranean saltmarshes. Two principal plant zones were observed: succulent zone vs. non-succulent zone, with a specific edaphic distribution for each plant community and for the proposed Limonium morphotypes treatment. A plant-soil model based on these three gradients is here proposed. Our results would complement the previous knowledge about plant-soil relationships in Mediterranean saltmarshes. [ABSTRACT FROM AUTHOR]

In the past several decades, dynamic global vegetation models (DGVMs) have been the most widely used and appropriate tool at the global scale to investigate vegetation-climate interactions. At the Institute of Atmospheric Physics, a new version of DGVM (IAP-DGVM) has been developed and coupled to the Common Land Model (CoLM) within the framework of the Chinese Academy of Sciences’ Earth System Model (CAS-ESM). This work reports the performance of IAP-DGVM through comparisons with that of the default DGVM of CoLM (CoLM-DGVM) and observations. With respect to CoLMDGVM, IAP-DGVM simulated fewer tropical trees, more “needleleaf evergreen boreal tree” and “broadleaf deciduous boreal shrub”, and a better representation of grasses. These contributed to a more realistic vegetation distribution in IAP-DGVM, including spatial patterns, total areas, and compositions. Moreover, IAP-DGVM also produced more accurate carbon fluxes than CoLM-DGVM when compared with observational estimates. Gross primary productivity and net primary production in IAP-DGVM were in better agreement with observations than those of CoLM-DGVM, and the tropical pattern of fire carbon emissions in IAP-DGVM was much more consistent with the observation than that in CoLM-DGVM. The leaf area index simulated by IAP-DGVM was closer to the observation than that of CoLM-DGVM; however, both simulated values about twice as large as in the observation. This evaluation provides valuable information for the application of CAS-ESM, as well as for other model communities in terms of a comparative benchmark. [ABSTRACT FROM AUTHOR]

Water regime is regarded as the primary factor influencing the vegetation distribution in natural wetland ecosystems. However, the effect of water regime change induced by large-scale hydraulic engineering on vegetation distribution is still unclear. In this study, multi-temporal TM/ETMC/OLI images and hydrological data from 1995 to 2015 were used to elucidate how the change in water regime influenced the vegetation distribution in the East Dongting Lake (EDTL), especially after the operation of the Three Gorges Dam (TGD) in 2003. Using unsupervised and supervised classification methods, three types of land cover were identified in the study area: Water and Mudflat, Grass, and Reed and Forest. Results showed that the total vegetation area in EDTL increased by approximately 78 km2 during 1995-2015. The areas of Reed and Forest and Grass exhibited a contrasting trend, dramatic increase in Reed and Forest but sharp decrease in Grass, particularly after the operation of TGD. The lowest distribution elevations of Grass and Reed and Forest decreased by 0.61 and 0.52 m, respectively. As a result of water level variation, submergence duration increased at 20-21 m and 28 m elevations (1-13 days), but significantly decreased at 22-27 m and 29-30 m elevations (-3 to -31 days). The submergence duration of Grass and Reed and Forest was 246 and 177 days, respectively. This study indicated that wetland vegetation pattern significantly changed after the operation of TGD, mainly as a result of changes in submergence condition. Submergence duration might be an effective indicator to predict the shift of vegetation distribution in EDTL, and which could provide scientific guidance for vegetation restoration and wetland management in this lake. [ABSTRACT FROM AUTHOR]

Specifying the positions and attributes of plants (e.g., species, size and height) during the procedural generation of large-scale forests in virtual geographic environments is challenging, especially when reflecting the characteristics of vegetation distributions. To address this issue, a novel graph-based neutral landscape model (NLM) is proposed to generate forest landscapes with varying compositions and configurations. Our model integrates a set of class-level landscape metrics and generates more realistic and variable landscapes compared with existing NLMs controlled by limited global-level landscape metrics. To produce patches with particular sizes and shapes, a region adjacency graph is transformed from a cluster map that is generated based upon percolation theory; subsequently, optimal neighboring nodes in the graph are merged under restricted growth conditions from a source node. The locations of seeds are randomly placed and their species are classified according to the generated forest landscapes to obtain the final tree distributions. The results demonstrate that our method can generate realistic vegetation distributions representing different spatial patterns of species with a time efficiency that satisfies the requirements for constructing large-scale virtual forests. [ABSTRACT FROM AUTHOR]