Vegetation Distribution Patterns Research Articles

Assessing Seasonal and Inter-Annual Changes in the Total Cover of Submerged Aquatic Vegetation Using Sentinel-2 Imagery

Remote sensing is a valuable tool for surveying submerged aquatic vegetation (SAV) distribution patterns at extensive spatial and temporal scales. Only regular mapping over successive time periods (e.g., months, years) allows for a quantitative assessment of SAV loss or recolonization extent. Still, there are only a limited number of studies assessing temporal changes in SAV patterns. ESA Sentinel-2 (S2) has a high revisiting frequency permitting the multi-temporal assessment of SAV dynamics both seasonally and inter-annually. In the current study, a physics-based IDA (Image Data Analysis) model was used for the reconstruction of past SAV percent cover (%cover) patterns in the Baltic Sea coastal waters based on S2 archived images. First, we aimed at capturing and quantifying intra-annual spatiotemporal SAV dynamics happening during a growing season. Modeling results showed that significant changes took place in SAV %cover: the extent of low-cover (0–30% coverage) and intermediate-cover (30–70% coverage) areas decreased, while high-cover (70–100% coverage) areas increased during the growing period. Secondly, we also aimed at detecting SAV %cover spatiotemporal variations inter-annually (over the years 2016–2022). Inter-annual variability in %cover patterns was greater in the beginning of the vegetation period (May). The peak of the growing period (July/August) showed greater stability in the areal extent of the %cover classes.

Effects of Geomorphic Spatial Differentiation on Vegetation Distribution Based on Remote Sensing and Geomorphic Regionalization

As the core area of human activities and economic development in the Xinjiang Autonomous Region, the hilly oasis zone of Xinjiang directly affects the regional sustainable development and stability of the ecosystem. Understanding the effects of different geomorphic types on vegetation distribution is crucial for maintaining vegetation growth and development, especially the improvement in the terrestrial ecological environment in arid areas under the background of climate change. However, there are few studies on the effect of spatial differences in detailed geomorphic types on vegetation distribution patterns. Therefore, this paper divides the Xinjiang hilly oasis zone into six geomorphologic level zones and innovatively investigates the influence of detailed geomorphologic types on the spatial distribution of vegetation and vegetation cover. Further, the area proportion of detailed landform types corresponding to different vegetation coverage in each geomorphic area was quantitatively calculated. Finally, the Geodetector method was used to detect the drivers of interactions between vegetation and the environment. The findings are shown as follows: (1) In the same climate zone, the spatial differentiation of landforms has a great influence on the vegetation distribution, manifesting as the significantly different vegetation distribution in different landform types. Grassland is the main vegetation type in the erosion and denudation of Nakayama; cultivated vegetation and meadows have a larger coverage in the alluvial flood plain and alluvial plain; and the distribution of vegetation in the Tianshan economic zone is characterized by obvious vertical zoning with the geomorphology. (2) The landform type and morphological types are the strongest driving factors for vegetation coverage with q values of 0.433 and 0.295, respectively, which effectually fill the gap caused by only using two terrain indicators, slope and elevation, to study the relationship between landforms and vegetation. (3) In addition, the improved nonlinear interaction resulting from the double factor of landform type and slope is 0.486, which has a stronger control on vegetation coverage than the single factor of landform type. These findings are conducive to enhancing the supply services of vegetation to the ecosystem in arid areas as well as providing important scientific guidance for the construction of ecological civilization and sustainable development in Xinjiang.

Elevation gradients alter vegetation attributes in mountain ecosystems of eastern Himalaya, India

The present study describes how vegetation (the tree layer) is shaped along the elevation gradients in the eastern part of the Indian Himalayan Region. Various vegetation attributes, distribution, population structure, and regeneration patterns of 75 tree species belonging to 31 families were studied. Tree species richness shows a low plateau (peaked between 1,300–1,500 m) with a linearly decreasing pattern above 1,500 m asl. Ericaceae was found as the dominant family, followed by Lauraceae and Rosaceae. The distributional pattern of species-to-genera ratio (S/G) did not follow any particular trends, while β-diversity increased along the elevation gradient. The Margalef index of species richness, the Menheink index of species richness, and the Fisher alpha were found to be highest at lower altitudes (1,000–1,500 m), while the Simpson index was highest at middle altitudes (2,600–3,000 m). Random distribution was shown by maximum tree species (47.3%), followed by a contagious distribution (42.9%), and regular distribution (10.8%). The regeneration of tree species was found to be good with a healthier number of seedlings (10.2%), fair (43.5%), poor (30.3%), while 16% were observed not regenerating. Acer laevigatum (1,500 m), Prunus nepalensis (3,300 m), Viburnum sympodiale (3,400 m) were among the new regenerating species at the respective altitudes. The population structure of tree species in terms of proportion of individuals in seedlings, saplings, and the adult class varied in all the elevation transects. Species with better regeneration on upper distribution limits have been recognized as probable for upward movement.

Alpine vegetation community patterns in the Khumbu region, Nepalese Himalaya

ABSTRACT The Himalayan alpine zone (HAZ)—a high-altitude zone above approximately 4,100 m.a.s.l., is projected to experience strong eco-environmental changes with climate change. As plants expand their range in this region, other processes are likely to be impacted; for example, flows and stores of water. A first vital step in conceptualizing HAZ ecohydrology is to understand the distribution pattern of HAZ vegetation communities. Satellite remote sensing provides one means of doing so, but the often patchy distribution of alpine vegetation creates challenges when using coarse-grained satellite data whose pixels are typically coarser than the grain of vegetation pattern. Here we use fine spatial resolution satellite imagery from WorldView-2 (2 m2 per pixel) coupled with elevation model data from the Copernicus GLO-30 product to produce a land cover classification for the HAZ. Field data captured during in situ surveys in the Gokyo valley, Nepal, were used to drive and then test a random forest classifier. Grassy meadows and dwarf shrubs belonging to the Rhododendron and Juniperus families dominate the ecology of the alpine zone in this region, so we created three vegetation classes for mapping indicative major plant communities dominated by these species. We found that altitude and aspect were dominant drivers of vegetation distribution in the HAZ and that the average vegetation cover of Rhododendron spp. and Juniperus spp. reduces with increasing altitude, as expected. South- and east-facing slopes were dominated by Juniperus spp., whereas north- and west-facing slopes were dominated by Rhododendron spp., and the growth extent of Rhododendron spp. (between 4,010 and 4,820 m.a.s.l.) and meadow (between 4,010 and 4,680 m.a.s.l.) were vertically wider than that of Juniperus spp. (between 4,010 and 4,660 m.a.s.l.). Results from this study demonstrate the vegetation distribution pattern in HAZ at the plant community level and provide an impetus for further studies that seek to understand ecohydrological interactions between dwarf plants and water flows and stores in the HAZ.

Bioturbating megafauna limits the expansion of Cymodocea nodosa seagrass meadows

In seagrass systems, there is a realization that biotic interactions affecting sediment stability might be as important as abiotic stressors in shaping the growth and distribution patterns of seagrass vegetation. However, few studies have looked at the interaction between seagrass and large (mega) bioturbating species, although through sediment reworking activity they may have the capacity to cause large scale impact on seagrass establishment. We assessed the effect of bioturbation by mobile megabioturbators (species lager than 5 cm) on subtidal seagrass (Cymodocea nodosa) using a manipulative field experiment where access by megabioturbators was restricted for 4 months during the growth season. There was a negative effect of megabioturbators on both the biomass and density of young seagrass ramets extending outwards from a mature seagrass meadow, but megabioturbators did not have a notable effect on seagrass growth in the meadows. Interestingly, the exclusion of megabioturbators in all tested habitats significantly modified the infaunal community composition, indicating the presence of complexity in biotic interactions and the possibility of indirect effects caused by the megabioturbators. Overall, megabioturbators have direct and indirect impact in seagrass habitats, playing a significant role in seagrass distribution patterns.

Earthworm diversity and community assemblage: influencing factors at plot-scale in urban areas

Soil fauna including earthworms play a crucial role in various ecosystem functions, thereby contributing to human well-being. The relationships between earthworm populations and environmental factors have frequently been established at regional scales, particularly in urban soils. However, the diversity and community assemblage of earthworms, as well as their influencing mechanism at plot scale, have rarely been studied. Based on the earthworm assemblage from 29 sites in 12 residential communities, the average earthworm abundance, biomass, and species richness were 59.0 individuals/m2, 21.7 ​g/m2, and 1.59 species, respectively. Based on a generalized linear mixed model, vegetation distribution pattern, vegetative cover type, and surrounding built environment all affected earthworm biomass. However, none of these residential variables significantly affected its community assemblage. Variation partitioning in canonical ordination revealed that edaphic properties, rather than landscapes, played a significant role in explaining the variation in its community assemblage, with an approximate contribution of 23%. The abundance and biomass of earthworms at the plot-scale in this study were consistent with previous studies at regional scales. However, the species richness at plot scale was lower than those at regional scale, suggesting that earthworm biodiversity may not accurately represent that at a larger scale, species-area relationship. The results indicate a shift in the driving factors of earthworm community assemblage from edaphic property variation at the plot scale to edaphic, historical, and biogeographical heterogeneities at the regional scale. Certain species that are sensitive to key edaphic/landscape parameters are potential candidates for monitoring soil ecological health.

Anthropogenic Impact and Ethnographic Study of Flora and Fauna of Silvassa Region

This research study presents a comprehensive investigation into the vegetation, floristic diversity, and anthropogenic influences within the Silvassa region. The study aims to elucidate the distribution patterns of vegetation, document the diverse flora, and understand the intricate relationships between plant species and their environment. Through a combination of participatory observation, data analysis, plant collection, interviews, and mapping, this research offers valuable insights into the botanical and ecological aspects of Silvassa. Both primary and secondary data sources were utilized to gather a holistic understanding of the area's flora and vegetation. The research methodology encompassed participation in local activities, soil property evaluation, and analysis of historical rainfall data, season-based plant collection, and ethnobotanical documentation. Interviews with local inhabitants facilitated the recording of traditional plant uses and local names. Additionally, herbarium specimens were created, rare endemic plants were cataloged, and photographic documentation of plant species and forest environments was undertaken. Group talks, field observations, and semi-structured interviews enriched the data collection process, providing qualitative dimensions to the study. However, certain limitations were acknowledged during the study

Sediment Grain Size Affects Vegetation Patterns in River-Dominated Deltas

River deltas contain some of the most densely populated areas in the world and are characterized by a rich biodiversity and highly productive ecosystems. Although previous studies have revealed that sediment grain size plays a key role in determining delta morphology, its subsequent effects on deltaic vegetation distribution patterns remain elusive. We used a theoretical templet to facilitate our study by conducting numerical experiments to simulate deltaic morphological evolution in response to various sediment grain sizes and explored the vegetation distribution determined by the elevation profile of a typical river-dominated delta. Our results showed that a fine-grained, cohesive delta would develop vegetation patterns transitioning from high- to low-elevation adapted vegetation species with increasing distance, whereas the same vegetation transformation trend could occur with decreasing distance to the center of a large-grained, noncohesive delta. The modeled vegetation distribution pattern of fine-grained, cohesive and large-grained, noncohesive deltas could be well demonstrated in the natural deltas. In addition, vegetation distribution patterns are related to the grain size-driven morphological processes of deltas, and the leading role of cohesive and noncohesive sediments on constructed delta is critical in determining the resulting vegetation distribution pattern. The dominance of each vegetation type would gradually become stable as delta matures. The interspecies competitions could influence distribution patterns of each vegetation type by enhancing the fragmentation of mid-elevation adapted vegetation. The effects of sediment grain size on the deltaic vegetation patterns associated with a delta’s morphological processes have potential implications for the conservation and restoration of deltaic habitats.

Boreal to temperate forests transition within Kunashir Island (the Kuril Archipelago): Insights from the novel vegetation map

The vegetation of the Kuril Islands remains insufficiently explored due to their remote location and harsh environment. Understanding the factors that influence vegetation distribution in this extensive volcanic chain of islands, spanning over a thousand kilometers, is important for global biogeography. Our paper presents the first vegetation map of Kunashir Island from the Kuril archipelago, compiled using Sentinel-2 medium-resolution multispectral satellite imagery, incorporating original field research data and the Random Forest machine-learning algorithm. The temperate broad-leaved forests are mainly composed of Acer mono subsp. mayrii and Quercus mongolica, predominantly limited to the southwestern coast, and true-boreal dark-coniferous Abies sachalinensis–Picea jezoensis forests located in the northeast part of Kunashir. The vegetation distribution pattern is associated with the warming effect of the Soja current on the east coast of Kunashir Island and the cooling effect of the Kuril current on the west coast. Kunashir's vegetation displays features of an ecotone between temperate and boreal zones. Still, the boundary between these zones should be drawn within the island, rather than between Kunashir and Hokkaido or Kunashir and Iturup, as suggested in some previous biogeographic generalizations.

Effects of coal mine waste dump on soil seed bank and vegetation distribution pattern

Long-term occupation of coal gangue dumping sites (CGDS) may destroy ecological environment of nearby area. However, how the CGDS affects the distribution pattern of soil seed banks and vegetation in the nearby area is not clear. In this study, we investigated soil seed bank and vegetation at different distances from the second CGDS of Yangchangwan in Ningdong mining area, Lingwu, Ningxia. The results showed that soil seed bank was mainly distributed in 0-10 cm layer and decreased with increasing soil depth. Species richness of soil seed bank and vegetation first increased and then tended to be stable with increasing distance to the CGDS. The influence range of CGDS on soil seed banks was 300-500 m and was 100-300 m on aboveground vegetation. The CGDS did not affect the vertical distribution pattern of soil seed bank, but significantly affected the horizontal distribution pattern of soil seed banks and aboveground vegetation. The key area of vegetation restoration around the CGDS was between 100 m and 300 m.

Topographic conditions as governing factors of mire vegetation types analyzed from drone‐based terrain model

AbstractQuestionsPrevious studies have shown that mire vegetation responds to fine‐scale differences in topography; however, very few studies have examined the relationship between multiple topographic conditions and vegetation distribution patterns by using topographic information with a resolution finer than microtopographic patches of sub‐meter scale in mires. Is it possible to predict vegetation distribution patterns in a mire using topographic information derived from drone imagery? How do topographic conditions affect the emergence of vegetation types?Location3 km2 of sloping mire in eastern Hokkaido, northern Japan.MethodsDigital surface models (DSMs) and orthomosaics were created using an affordable drone (Phantom3 advanced) and photogrammetry. We calculated 23 variables reflecting topographic conditions from DSMs. The locations of four vegetation types (Moliniopsis japonica–Eriophorum vaginatum, ME; Moliniopsis japonica–Carex lasiocarpa, MC; Sphagnum fuscum–Ledum palustre, SL; and Carex lyngbyei–Thelypteris palustris, CT) were recorded by field survey and orthomosaics. Random forest models that predicted vegetation types from topographic variables were created and we evaluated the prediction accuracy, importance of variables and effect of variables on the occurrence probability of the vegetation types.ResultsAll predictive indicators (recall, precision, overall accuracy, kappa) were very high (>0.9). Important variables for modeling were altitude, relative height to the surroundings, slopes at a scale of several 10 m, soil wetness index and terrain ruggedness. Each vegetation type appeared under different topographic conditions; altitude was a key factor in ME and MC, and slope in CT. SL showed patchy distribution predictions on hummocks.ConclusionsVegetation distribution in the mire was strongly related to topographic information based on the DSMs. Analysis of the variable effects indicates that the emergence of the vegetation types was explained by a combination of multiple topographic conditions. This approach has the outstanding advantages of obtaining many survey points quickly and retrieving topographic conditions difficult to measure using on‐ground field surveys.

Alternating dominant effects of temperature and precipitation along elevational gradient on the alpine and subalpine vegetation activities in southwestern China

Elevation plays a pivotal role in modulating hydroclimatic dynamics, changing vegetation activity and shaping vegetation distribution patterns in alpine regions. Nevertheless, a conspicuous knowledge gap persists regarding the interaction between climate drivers on vegetation activity. In this study, we investigated the spatio-temporal patterns of the Normalized Difference Vegetation Index (NDVI), a proxy for vegetation activity, and examined its interactions with temperature (T) and precipitation (P) along elevational gradient (EG) in the Alpine and Sub-alpine Woodlands of Southwest China (ASWSC) during 2001–2018. We found that approximately 24% vegetation in ASWSC exhibited significant greening trend, as a result of regional warming and slight wetting during the study period. The greening and browning rates were both elevational asymmetric, with higher rates at lower elevations. We also illustrated an alternating domination of T - P on vegetation activity along EG. This suggested a roughly antagonistic effect between the two drivers within the whole vegetation elevation range except for a synergistic effect in the sub-alpine forests zone between 2300 - 4200 m. The antagonistic effect tended to be more pronounced in warm and dry years, while the synergistic effect was more evident in cold and wet years. Specifically for different vegetation types, we found an insignificant T - P interactive effect along EG in indigenous evergreen needleleaf forest (ENF) and evergreen broadleaf forest (EBF), in contrast to the significant synergistic effect in the regenerated deciduous broadleaf forest (DBF) and mixed forest (MF) and antagonistic effect in shrubland and grassland types. In summary, our study revealed alternating-dominant effects of temperature and precipitation on vegetation activity along EG. These findings will deepen our understanding of vegetation resistance and resilience to climate change and eventually contribute to establishing a scientific foundation for effective ecosystem management and conservation practices in alpine region.

Flow Structures in Open Channels with Emergent Rigid Vegetation: A Review

On the edges of rivers where the flow velocity is low, aquatic plants flourish, with emergent rigid herbs being the most common. Since the flow structures of vegetated flow are strongly influenced by vegetation distribution patterns, homogeneous and heterogeneous canopies are defined based on the characteristics of vegetation distribution. A review summarizing recent advances in flow structures under the influence of different types of canopy arrangements, including ribbon-like homogeneous canopies, ribbon-like heterogeneous canopies, and patched heterogeneous canopies, is needed. Their flow development process, shear layer properties, coherent structure features, and momentum exchange characteristics are summarized, and a future research agenda for an in-depth understanding of the interactions between vegetation and flow is also highlighted.

Influence of Climate, Topography, and Hydrology on Vegetation Distribution Patterns—Oasis in the Taklamakan Desert Hinterland

Vegetation in natural desert hinterland oases is an important component of terrestrial ecosystems. Determining how desert vegetation responds to natural variability is critical for a better understanding of desertification processes and their future development. The aim of this study is to characterize the spatial distribution of vegetation in the natural desert hinterland and to reveal how different environmental factors affect vegetation changes. Taking a Taklamakan Desert hinterland oasis as our research object, we analyzed the effects of different environmental factors on desert vegetation using a time-series normalized difference vegetation index (NDVI) combined with meteorological, topographic, and hydrological data, including surface water and groundwater data. Vegetation was distributed in areas with high surface water frequency, shallow groundwater levels, relatively flat terrain, and dune basins. NDVI datasets show greening trends in oasis areas over the past 20 years. The frequency of surface water distribution influences water accessibility and effectiveness and shapes topography, thus affecting the spatial distribution pattern of vegetation. In this study, areas of high surface water frequency corresponded with vegetation distribution. The spatial distribution of groundwater depth supports the growth and development of vegetation, impacting the pattern of vegetation growth conditions. Vegetation is most widely distributed in areas where the groundwater burial depth is 3.5–4.5 m. This study provides data for restoring riparian vegetation, ecological water transfer, and sustainable development.

Spatiotemporal heterogeneity of inundation pattern of floodplain lake wetlands and impact on wetland vegetation

The inundation pattern is an important ecohydrological indicator for studying floodplain lake wetlands, as it is the key factor affecting the wetland vegetation distribution patterns. Poyang Lake, the largest freshwater lake in China, is a typical floodplain lake wetland. This study presents a hydrodynamic model and vegetation survey of Poyang Lake, analyzed the spatiotemporal heterogeneity of the inundation pattern (inundation duration and depth), assessed the response patterns of wetland vegetation concerning the inundation pattern, and examined the impact of the proposed Poyang Lake Water Conservancy Hub (PLWCH) on the inundation pattern and wetland vegetation. The results revealed that the inundation pattern of Poyang Lake had significant spatial heterogeneity. Inundation pattern was found to have a significant impact on the vegetation succession. The response relationship between the distribution areas of different wetland vegetation types and inundation pattern was in accordance with the Gaussian curve, and the ecological threshold range of the Carex spp. community was the greatest. Owing to factors such as climate change and anthropogenic activities, the inundation pattern of Poyang Lake varied significantly since 2003, with the average inundation duration and average inundation depth decreasing by 15 d and 0.32 m, respectively. Consequently, the spatial distribution of wetland vegetation changed significantly, whereby the Carex spp., Polygonum criopolitanum, and Phalaris arundinacea communities extended down to the lower elevation zone. In the future, the PLWCH may result in increases in the inundation duration and depth, restrain the downward vegetation extension trend, and promote the vegetation to move to higher elevations similar to the status prior to 2003. These findings provide a detailed description of the spatiotemporal heterogeneity of the inundation pattern and the drivers of wetland vegetation distribution patterns in floodplain lake wetlands, serving as a scientific basis for conservation and restoration of these ecosystems.

Catchment-scale patterns of geomorphic activity and vegetation distribution in an alpine glacier foreland (Kaunertal Valley, Austria)

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.

Effects of vegetation distribution and landscape pattern on water conservation in the Dongjiang River basin

Water conservation is important for maintaining a well-functioning ecosystem. Using the Soil & Water Assessment Tool (SWAT) model, we simulated the hydrological cycle and evaluated the spatial and temporal variability of water conservation in the Dongjiang River. Spatial autocorrelation analysis and geographically weighted regression (GWR) were used to investigate the effects of landscape patterns and normalized difference vegetation index (NDVI) on water conservation. Four hydrological stations with regular rate, validation period deterministic coefficient R2, and efficiency coefficient ENS (Nash–Sutcliffe) met the adaptation requirements, and the model accurately simulated the hydrological process of the Dongjiang River. The interannual variation of water conservation showed a non-significant upward trend (0.12 mm/10a), and the spatial distribution is given as follows: midstream > downstream > upstream. Regression coefficients of NDVI of high, medium, and low-density forest land in the sub-basin with water conservation decreased from the upper to lower reaches. The negative correlation of LPI, CONTAG, and IJI was concentrated in the upper reaches and southeast of the basin, and that of SHDI was concentrated in the middle and lower reaches; the regression coefficients of LPI and PLAND of forest land decreased from middle reaches to north and south, and ED decreased from southwest to northeast. The positive correlation of grassland was concentrated in the watershed’s upper reaches; the regression coefficient of construction land showed an increasingly negative correlation from the lower to upper reaches. This study provides scientific support for promoting the hydrological ecosystem and comprehensive utilization of water resources in the Dongjiang River basin.

A Quantitatively Divided Approach for the Vertical Belt of Vegetation Based on NDVI and DEM—An Analysis of Taibai Mountain

Vertical vegetation differentiation is the most important form of spatial pattern in mountainous areas. It is of great significance to accurately divide vegetation into vertical zones for the study of mountain ecosystems and ecological protection. In order to accurately divide the vertical zone of mountain vegetation and determine the spatial distribution of mountain vegetation, the relationship between the vegetation index of various vegetation types and altitude was examined using remote sensing and geographic information technology. Taking Taibai Mountain, the main peak of the Qinling Mountains in China, as the study area, based on the difference in NDVI between summer and autumn (DNSA), this work constructed a DEM-NDVI scatter plot and quantified the boundary of the vertical zone by the half-peak width calculation method. The findings showed that: (1) the vertical distribution pattern of mountain vegetation may very well be reflected in the scatterplot that NDSA and DEM created; (2) Six vertical belts could be accurately identified to the meter level on Taibai Mountain’s south slope. Up to the altitude, the oak forest zone from the bottom of the mountain to the elevation of 1919 m, the pine-oak mixed forest zone is distributed in 1919–2331 m, the birch forest is distributed in 2115–2585 m, the fir forest is distributed in 2516–3150 m, the redwood forest is distributed in 3109–3551 m, and the alpine scrub meadow is distributed in 3551 m to the peak. On the north slope, 1053–2087 m above sea level is oak forest, 2087–2693 is birch forest, 2562–3006 is fir forest, 2987–3513 m is redwood forest, and 3513 to the top of the mountain is alpine scrub meadow; and (3) the distribution pattern of the vegetation vertical belt on the DEM-NDVI scatter plot was essentially compatible with the vegetation classification results derived from remote sensing images. The DEM-NDVI scatter plot can reflect the average distribution of vegetation population and can more accurately express the characteristics of vegetation vertical zone changes with altitude.

Vegetation responses to ecological water delivery and prolonged droughts in an artificial desert oasis, Northwestern China

Irrational water usage in the middle reaches of inland rivers is detrimental to downstream oases, and the Qingtu Oasis is a typical downstream oasis that is degraded by water resource scarcity. The Qingtu Lake ecological water diversion project (EWDP) has restored the oasis, but the response pattern of different vegetation communities to environmental water and the dominant drivers of vegetation dynamics are not clear. Here, based on ground and satellite observations, this study investigated the spatial and temporal patterns of vegetation distribution and growth in the Qingtu Oasis from 2010 to 2022, and the reasons for the interannual variability in vegetation growth were also explained. The results showed that temporal variations in the distribution area of Phragmites australis (PA) followed a logistic curve after the EWDP, which increased rapidly from 2010 to 2019 and stabilized afterward. Meanwhile, the distribution area of Nitraria tangutorum (NT) presented a linear increase during the study period, with a 121.2% increase. Due to water inundation, the central region was occupied by PA communities, while NT communities moved to the edge. The spatial connectivity of PA patches increased significantly in contrast to the overall fragmentation tendency of NT patches in 2010–2022. The oasis tended to be homogenized and aggregated according to the morphological spatial pattern analysis, along with the landscape diversity and contagion indices. Enhanced vegetation growth, as indicated by the normalized difference vegetation index (NDVI), was observed in 76.1% of the vegetated lands, and the NDVI increasing rate was high near the canal. Using the random forest model, this study found that changes in groundwater depth were the most important driver of NDVI variability. The following influencing factors were atmospheric CO2 concentration, water inundation area and water delivery amount. In the absence of large increases in water delivery amount, oasis vegetation growth was susceptible to prolonged droughts. This study uncovers a nonlinear response of different vegetation communities to climate change and the EWDP in the downstream region of arid endorheic basins and identifies meteorological droughts as a key factor that should be fully considered in water delivery strategies. These findings lay a solid foundation for managing oasis restoration and water resource allocation in arid inland river basins.

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

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