Monitoring Environmental Degradation and Restoration of Wetlands and Arid Lands Using Remote Sensing and Big Geospatial Data

1. Introduction

Intensified human activities and climate change are posing great challenges to the fragile thresholds of ecosystems [1,2]. Some developments, e.g., deforestation, urban expansion, and pollution, directly compromise ecological structure and function [3,4,5], while climate change threatens ecosystem services through rising temperatures, extreme weather events, and sea-level rise [6,7,8]. Together, all these external disturbances not only weaken ecological resilience and natural recovery [9,10], but also result in biodiversity decline, essential ecosystem services degradation, and ultimately threaten to push vulnerable ecosystems toward irreversible collapse [11].

Wetlands and arid lands rank among the most fragile ecosystems on earth, and are highly vulnerable to climate change and human disturbances [12,13]. Wetlands, usually defined as transitional zones between terrestrial and aquatic environments, are among the world’s most productive ecosystems and provide multiple ecosystem services for both humans and wildlife [14,15]. Meanwhile, arid lands, characterized by sparse vegetation and low productivity, support more than two billion people by providing critical crop yields and forage for wildlife and livestock [16,17], and have also been identified as key contributors to global atmospheric CO₂ dynamics [18,19]. However, over the past few decades, wetlands and arid lands have experienced widespread degradation and loss dramatically due to enhanced climate change and intensified anthropogenic activities [20]. Thus, advanced monitoring of environmental degradation and restoration of wetlands and arid lands is essential for improving our understanding about these ecosystem conditions and management implementations, such as ecosystem protection, biodiversity conservation, and habitat assessment.

The aim of this Topic is to capture the recent advancements in the applications of remote sensing and big geospatial data in the monitoring of global or regional wetlands and arid lands, such as automatic and accurate mapping algorithms, spatial–temporal dynamics and identification of major driving factors for the gains and losses of wetlands and arid lands. This Topic demonstrates the broad interest of scholars and readers in the research topic of ecology, environment, and geography, which received almost 60 k views since February 2023. Furthermore, it features 21 papers, including 8 articles from Remote Sensing, 6 articles from Land, 4 papers from Diversity, 2 papers from Forests, and 1 paper from Conservation.

2. An Overview of Published Articles

2.1. Innovations in Remote Sensing Methods and Technologies for Ecosystem Monitoring

Accurate monitoring of ecosystem structure, function, and dynamics of wetlands and arid lands increasingly relies on advances in remote sensing technologies. A scientific challenge lies in effectively integrating multi-source data with advanced algorithms to improve monitoring accuracy, which is a critical index in ecological research and environmental management. Addressing this, Fan et al. (Contribution 2) captured near-surface vegetation phenology with high fidelity using multi-source remote sensing datasets. For heavily disturbed underwater mining areas, Mi et al. (Contribution 7) developed an integrated “Status–Habitat–Potential” assessment framework using time-series remote sensing and the Google Earth Engine (GEE) platform to evaluate current vegetation conditions, habitat characteristics, and ecological recovery potential, thereby offering a novel perspective for conservation planning. Meanwhile, Jun et al. (Contribution 11) combined LiDAR and hyperspectral observations to map the spatial distribution of foliar carbon, nitrogen, and phosphorus, delivering valuable insights for assessing the functional recovery of restored ecosystems.

At the same time, several studies have reported methodological advances enabling large-scale monitoring and intelligent analysis in arid environments. For instance, one study demonstrated the effectiveness of mapping dryland ecosystems by integrating GEE with random forest algorithms (Contribution 14). In addition, a newly proposed dual-branch embedded multivariate attention network effectively fused spectral and multi-scale spatial features and improved hyperspectral image classification accuracy significantly. This breakthrough underscores the potential of deep learning architectures to extract complex ecological information from big remote sensing data (Contribution 13).

2.2. Evolutionary Dynamics and Landscape Pattern Changes in Ecosystems

Understanding the long-term trajectories of wetland and arid land ecosystems has emerged as a pivotal issue in ecological management and restoration science. In this Topic, Ontel et al. (Contribution 6) developed an integrated assessment framework based on multi-source remote sensing indicators to systematically analyze the spatiotemporal patterns and recent trends of land degradation. Their results reveal pronounced regional differences in these processes, which are primarily driven by the combined effects of land-use change and climatic forcing. Similarly, Xue et al. (Contribution 15) utilized a 40-year sequence of remote sensing data and landscape metrics to demonstrate significant wetland shrinkage, frequent transitions among wetland types, and increased landscape fragmentation. This evidence underscores the cumulative risk that intensive human disturbance and climate variability pose to the long-term stability of wetland ecosystems.

In addition, long-term ecosystem changes are further elucidated by research focusing on hydrological processes and forest structural dynamics. Varugu et al. (Contribution 20) applied rapid-repeat InSAR for the first time to monitor tidal influences on hydrological connectivity in Louisiana’s coastal wetlands, and captured intermittent flow pathways that are undetectable by traditional optical sensors. Meanwhile, Ferreira et al. (Contribution 21) analyzed stem mortality and tree recruitment dynamics between 2012 and 2021, and identified an accumulative effect of recurrent droughts. This effect was manifested in elevated mortality rates and diminished recruitment capacity, thereby amplifying forest ecosystems’ vulnerability to future extreme climate events. Together, these studies, which span diverse ecosystem types and spatial scales, clarify the multi-dimensional evolutionary trajectories of arid and wetland ecosystems, offering crucial scientific evidence for identifying ecological tipping points and vulnerable zones.

2.3. Vegetation Response Mechanisms and Ecological Processes Under Water Limitation

Severe water limitation is the primary constraint on ecosystems in arid regions and hydrologically stressed wetlands. Studies spanning dryland river floodplains, semi-arid shrublands, desert riparian forests, and coastal salt marshes reveal both shared and distinct ecological responses to water stress. In areas governed by hydrological processes, plant communities show high sensitivity to water availability. In the Populus pruinosa floodplain forests of Central Asia, for instance, flood frequency and groundwater depth were found to shape species composition and diversity, confirming that river hydrology directly controls community assembly in arid river-floodplain systems (Contribution 4). Research in the western Loess Plateau further verified that soil moisture and topography affect species richness and govern community assembly via environmental filtering and biotic interactions, a result that clarifies the formation of distinct functional communities in semi-arid shrublands under environmental pressure (Contribution 9). Likewise, in desert riparian forests of northwestern China, rainfall and soil moisture were quantitatively determined as key drivers of compositional variation, which underscores the decisive role of water availability in the formation of riparian structure and function (Contribution 17).

At finer biological scales, drought shapes the persistence strategies of species and their long-term evolutionary trajectories. In the highly drought-tolerant cactus Sclerocactus wrightiae, a persistent soil seed bank functions as an “ecological insurance mechanism” that aids population recovery after drought or disturbance, underscoring the role of belowground life stages in the conservation of rare arid-land species (Contribution 10). Meanwhile, in coastal Spartina salt marshes, comparative phylogeographic and historical demographic analyses of three common animal species revealed that past sea-level fluctuations and environmental gradients jointly influenced genetic structure and dispersal history, which reflects long-term adaptation and differentiation within these wetland ecosystems (Contribution 3). Collectively, spanning from community structure to species persistence and evolutionary history, these studies demonstrate how water availability, environmental filtering, and historical processes collectively form the biodiversity patterns and ecological dynamics observed in arid and wetland ecosystems.

2.4. Ecological Restoration, Constructed Wetlands, and Ecosystem Function Assessment

Ecological restoration has emerged as a vital strategy to combat wetland degradation, water scarcity, and the loss of ecosystem services. Chakraborti et al. (Contribution 1) evaluated the treatment of reverse osmosis concentrate (ROC) in constructed wetlands and its effects on the restoration of a natural coastal wetland, which demonstrates an innovative approach that combines wastewater reuse with coastal wetland rehabilitation. Meanwhile, Coccia et al. (Contribution 16) employed airborne hyperspectral data to retrieve water depth, turbidity, and chlorophyll concurrently, a method that supports multi-metric monitoring of restored water bodies and provides a novel framework for assessing the water-quality outcomes of wetland restoration projects. Together, these studies deliver valuable practical experience and theoretical insights that inform ecological restoration, resource utilization, and environmental management in arid and wetland ecosystems.

2.5. Synergistic Analysis of Land Use, Ecosystem Functions, and Carbon Goals

Under global environmental change, coordination among land-use patterns, ecosystem services, and carbon sequestration capacity has become a key challenge for sustainable management in arid lands and wetlands. Jin et al. (Contribution 8), for example, developed an evaluation framework that integrates agricultural production efficiency and ecological transition efficiency in the Yangtze River Economic Belt. Their analysis revealed clear spatiotemporal variations between agricultural development and ecological protection, providing quantitative support for both agricultural modernization and ecological governance. At the urban scale, Wang et al. (Contribution 18) assessed the carbon sequestration potential under various spatial configurations and management scenarios in Shanghai’s constructed wetlands, offering strategic guidance for wetland-based pathways toward urban carbon neutrality.

At the community and resource-development levels, the effects of land-use decisions on ecosystem functions are more immediate. In the Affem Boussou community forest, changes in land use correlated closely with shifts in plant zonation diversity, which shows that decisions at the community level substantially affect forest structural diversity and the stability of local ecosystem services (Contribution 5). In the Gobi region, Wang et al. studied the influence of large-scale photovoltaic development and observed a clear day–night asymmetry in land surface temperature. This suggests that while solar installations help reduce carbon emissions, they may also modify the surface energy balance and impact ecological processes in arid areas (Contribution 12). At the scale of dryland mountains, Yuan et al. (Contribution 19) developed an ecological security pattern for the Kunlun Mountains based on ecosystem services and the distribution of dominant species. Their work identified key ecological sources and corridors, highlighting the need to integrate land-use layout, ecosystem services, and ecological security objectives into spatial planning.

3. Conclusions

This Topic of “Environmental Monitoring and Environmental Restoration for the Arid Lands and Wetlands” enhances the understanding of wetlands and arid lands by highlighting recent advances in ecosystem monitoring, ecological process analysis, restoration assessment, and land use–ecosystem interactions. By integrating remote sensing and geospatial technologies, the contributions collectively illustrate how modern observational tools enhance the detection and interpretation of ecosystem changes in these sensitive environments. The 21 articles provide new data, methods, and insights that support ecological conservation, improve restoration practices, and inform sustainable land-use planning. Together, their findings provide a robust scientific foundation for managing wetlands and arid regions amid escalating climatic and anthropogenic pressures. Looking forward, future efforts should prioritize long-term monitoring, predictive modeling, and interdisciplinary approaches to better anticipate ecosystem responses and enhance resilience. Ongoing innovation in Earth observation and ecological assessment will remain crucial to protect these vulnerable ecosystems in a rapidly changing world.