Search Results (496)

Wetlands play a crucial role in maintaining biodiversity and ecological balance. Preserving the ecological security of wetlands is critically important for regional environmental protection and sustainable development. However, in the core area of the Wuhan metropolitan circle, which is rapidly urbanizing, its wetlands are more susceptible to external natural environmental risks, such as changes in temperature and rainfall, as well as risks to human activity, such as social and economic activities, urban expansion, land use changes, and population growth. Meanwhile, the internal vulnerability of wetlands in terms of their spatial extent, structure, and functions also exacerbates ecological risks. These factors collectively influence the formation and development of wetland ecological risks. This study aims to comprehensively assess wetland ecological risks in the core area of the Wuhan metropolitan circle by combining external hazards and internal vulnerabilities and to construct and optimize the wetlands’ ecological security pattern. We used the MSPA method to identify potential ecological sources. Additionally, the MCR model was employed to integrate ecological risk assessment results into the resistance surface, identify potential ecological corridors and nodes, construct the wetland ecological security pattern for the urban circle, and propose specific optimization strategies. In total, 31 primary and 106 secondary ecological sources were selected, along with 20 primary and 42 secondary ecological nodes. Furthermore, 10 major ecological corridors were constructed. Considering the landscape characteristics of the wetlands in the core area of the Wuhan metropolitan circle, the southern Yangtze River region will center around the Liangzi Lake group to establish a crucial corridor network, promoting overall wetland restoration and connectivity. Meanwhile, the northern Yangtze River region will form a chain-like distribution along the river, creating diverse ecosystems. This study provides a theoretical foundation for constructing and optimizing the ecological security pattern of wetlands, laying a solid groundwork for promoting regional wetland conservation and sustainable development. Full article

Considering the importance of coastal wetlands as key land resources and the ecological degradation caused by large-scale and multi-stage reclamation, as well as the significant synergistic and superimposed effects of reclamation on wetland degradation in temporal and spatial dimensions, it is vital to conduct in-depth research on the impact mechanisms and cumulative effects of reclamation on wetland degradation. However, the existing methods for evaluating these cumulative effects still have some shortcomings in characterizing the spatiotemporal scale. Consequently, it is urgent to introduce or develop a cumulative effect evaluation method based on remote sensing. Taking the Jiangsu coastal wetland as a typical case study area, the present study constructed a cumulative effect evaluation method based on calculus theory combined with landscape succession modeling and statistical analysis. This method was then used to quantitatively analyze the impacts and cumulative effects of reclamation on wetland degradation in the Jiangsu coastal region from 1980 to 2024. The results show that degradation of the Jiangsu coastal wetlands over the last 45 years covered 2931.54 km², accounting for 46.92% of the area in 1980. This degradation primarily reflects a shift from natural wetland to constructed wetland. In addition, the reclaimed area of 2119.61 km² is mainly used for aquaculture and agricultural cultivation. The reclamation rate of Jiangsu showed insignificant fluctuations and significant spatial differences. The reclamation rate of the north counties and cities presented a downward trend, while that of the south counties and cities presented an upward trend. Reclamation has a significant impact on wetland degradation, with a contribution rate of 50.62%. The cumulative effect in the study area reached its maximum value in 2015, except for Nantong City. This study provides a new perspective for quantitatively analyzing the impacts and cumulative effects of coastal wetland reclamation and provides guidance for the effective management and sustainable utilization of coastal wetland resources. Full article

Upper estuarine forested wetlands (UEFWs) play an important role in the sequestration of atmospheric carbon (C), which is facilitated by their position at the boundary of terrestrial and maritime environments but threatened by sea level rise. This study assessed the change in aboveground C stocks along the estuarine–riverine hydrogeomorphic gradient spanning salt-impacted freshwater tidal forested wetlands to freshwater forested wetlands in seasonally tidal and nontidal landscape positions. Standing stocks of C in forested wetlands were measured along two major coastal river systems, the Winyah Bay in South Carolina and the Savannah River in Georgia (USA), replicating and expanding a previous study to allow the assessment of change over time. Aboveground C stocks on these systems averaged 172.9 Mg C ha⁻¹, comparable to those found in UEFWs across the globe and distinct from the terrestrial forested ecosystems they are often considered to be a part of during large-scale C inventory efforts. Groundwater salinity conditions as low as 1.3 ppt were observed in conjunction with losses of aboveground C. When viewed in context alongside expected sea level rise and corresponding saltwater intrusion estimates, these data suggest a marked decrease in aboveground C stocks in forested wetlands situated in and around tidal estuaries. Full article

An aerated greenhouse ecosystem, often referred to as a Living Machine^®, is a technology for biological wastewater treatment within a greenhouse structure that uses plants with their roots submerged in the wastewater. This system has a small footprint relative to traditional onsite wastewater treatment systems and constructed wetland, can treat high-strength wastewater, and can provide a high level of treatment to allow for reuse for purposes such as irrigation, toilet flushing, and landscape irrigation. Synthetic and actual craft beverage wastewaters (wastewater from wineries, breweries, and cideries) were examined for their treatability in bench-scale greenhouse ecosystems. The tested wastewater was high strength with chemical oxygen demands (COD) concentrations of 1120 to 15,000 mg/L, total nitrogen (TN) concentrations of 3 to 45 mg/L, and total phosphorus (TP) concentrations of 2.3 to 90 mg/L. The COD, TN, and TP concentrations after treatment ranged from below 125 to 560 mg/L, 1.5 to 15 mg/L, and below 0.25 to 7.8 mg/L, respectively. The results confirm the ability of the aerated greenhouse ecosystem to be a viable treatment system for craft beverage wastewater and it is estimated to require 54 and 26% lower hydraulic retention time than an aerobic lagoon and a low temperature, constructed wetland, respectively, the types of systems that would likely be used for this type of wastewater for onsite locations. Full article

In recent years, the Chinese government implemented many policies and actions to restore coastal wetlands. This study focused on assessing how these projects have influenced the landscape patterns of the Liaohe Estuary, an area of critical importance. By analyzing remote sensing images from 2009 to 2022, we determined the spatiotemporal changes in landscape pattern, fragmentation, and conversion. Results showed that (1) Reed (Phragmites australis) fields were the dominant landscape feature and covered 46.3–48.2% of the area; however, road was the serious factor in fragmenting these wetlands. Seepweed (Suaeda salsa) marshes, an iconic and characteristic wetland of the region, gradually expanded towards the estuary and coast over the study years. (2) Landscape fragmentation increased and seasonally changed during the study period and restoration measures actually resulted in more fragmentation of the landscape. (3) Ponds replaced 14.28 km² natural landscape in the development stage and 40.93 km² were restored to natural landscape during restoration and maintenance. (4) Active restoration projects caused landscape fragmentation to sharply increase initially, but then fragmentation declined as passive restoration continued in the maintenance stage. This study suggests that road construction should be carefully deliberated in ecologically sensitive areas and that ecological restoration (a combination of active and passive restoration) in the Liaohe Estuary region showed evidence of temporal lag and hysteresis that may be important for research in the future. Full article

Research on ecosystem services (ES) has become central to landscape planning, framing the relationship between people and nature. In Sub-Saharan regions, local communities rely heavily on wetlands for various ES. For the first time, we assessed perceptions of ES provided by these wetlands, focusing on marshes, peatlands, swamps, and inland valleys/floodplains in eastern DR Congo. Fieldwork combined with a survey of 510 households, using both open-ended and 35 direct questions, evaluated perceptions of wetland ecosystem services (WESs). The most frequently reported WES were provisioning (38%) and regulating (24%), while supporting (22%) and cultural (16%) were less mentioned. These perceptions varied across wetland types and among communities based on gender, religion, seniority in wetland use, land tenure, and educational level. Rural communities had a deep relationship with nature, shaped by cultural, economic, and geographical factors. Wetlands are viewed positively as sources of goods but also negatively as sources of diseases. A structural equation model (SEM) helped in identifying four latent variables—livelihood, knowledge, personal, and geographical factors—driving WES perceptions. These findings are relevant for developing wetland management policies and suggest including community engagement and collaboration in wetland restoration and regulatory frameworks. Full article

The Shaanxi section is the central region of the Loess Plateau. Its unique wetland environment plays an indispensable role in regional ecological environment security. Clarifying the characteristics of wetland changes in the region is an important prerequisite for wetland management and protection. This study, based on the remote sensing data of the Shaanxi section of the Loess Plateau, analyzed the changes in the wetland area and type transfer in this region in 1980, 1990, 2000, 2010 and 2020 using the wetland dynamic degree model, the Markov transfer matrix, the landscape pattern index, and centroid analysis. The results showed that, from 1980 to 2020, the total wetland area and natural wetland area in the Shaanxi section of the Loess Plateau continued to shrink, decreasing by 79.35 km² and 80.50 km², respectively, while the artificial wetland area increased by 1.14 km². Among the regions, Xi’an experienced the most significant reduction, with a total decrease of 83.04 km² over 40 years, followed by Xianyang City, where the wetland area decreased by 6.50 km². In contrast, the wetland areas of Yulin City, Weinan City, Yan’an City, Baoji City and Tongchuan City increased slightly. From 1980 to 2020, the change in the wetland types in the Shaanxi section of the Loess Plateau was mainly characterized by transfers between beach lands and river canals. River canals are the primary type of wetland in this region. The degree of fragmentation is the highest in reservoir potholes, while marshes have the largest clumpiness index. Over the same period, the centroid of the wetlands in the Shaanxi section of the Loess Plateau moved from south to north as a whole, although, between 1990 and 2000, the centroid position remained relatively stable. These results provide a theoretical basis and data support for wetland monitoring and protection in the Shaanxi section of the Loess Plateau and also provide a reference for the protection and sustainable development of other inland wetland resources in arid and semi-arid regions. Full article

Rapid urbanization leads to fragmentation and reduced connectivity of urban landscapes, endangering regional biodiversity conservation and sustainable development. Constructing a red, green, and blue spatial ecological network is an effective way to alleviate ecological pressure and promote economic development. Using circuit theory, hydrological analysis, and suitability analysis, this study constructs a composite ecological network under urban–rural integration. The results show the following: (1) A total of 22 ecological corridors with a length of 349.20 km, 22 ecological pinch points, and 22 ecological barrier points are identified in the municipal area, mainly distributed in Haidong Town. There are 504 stormwater corridors, which are more evenly distributed, 502 riverfront landscape corridors, and 130 slow-moving landscape corridors. (2) A total of 20 ecological corridors, with a length of 99.23 km, 19 ecological pinch points, and 25 barrier points were identified in the main urban area, and most of them are located in the ecological corridors. There are 71 stormwater corridors, mainly located in the northwestern forest area, 71 riverfront recreation corridors, and 50 slow-moving recreation corridors. (3) Two scales of superimposed ecological source area of 3.65 km², and eleven ecological corridors, are primarily distributed between Erhai Lake and Xiaguan Town. There are two superimposed stormwater corridors and fourteen recreational corridors. The eco-nodes are mostly distributed in the east and south of Dali City; wetland nodes are mainly situated in the eighteen streams of Cangshan Mountain; and landscape nodes are more balanced in spatial distribution. The study results can provide a reference for composite ecological network construction. Full article

Understanding the spatial heterogeneity of bird community distribution within urban greenways is crucial for optimizing ecological functions and supporting urban biodiversity. While ecological corridors enhance connectivity and biodiversity, specific mechanisms by which landscape composition and configuration influence bird diversity remain unclear. This study examines bird community distribution along the Qingshan Lake Greenway in Hangzhou during autumn and winter, using 17 observation points across wetlands, forests, and mixed habitats. The key findings indicate that wetlands have significantly higher species richness compared to forests and mixed habitats, underscoring wetlands’ critical role in supporting diverse bird communities. Greenways primarily facilitate short-distance bird movement with limited permeability between habitats. Additionally, greenway effectiveness in enhancing bird diversity depends heavily on design and structural characteristics. This research highlights the necessity of incorporating microhabitat design and diverse habitat configurations in greenway planning to enhance ecological connectivity and biodiversity. It provides essential insights for urban planners and ecologists, emphasizing detailed landscape composition and configuration analyses. Future research should include year-round studies and advanced ecological monitoring technologies to validate and expand these findings, ultimately contributing to more effective urban biodiversity conservation and sustainable development strategies. Full article

The morphological aspects of urban growth on wetlands in Africa are under-researched. Using the Densu Delta Ramsar site in Accra, Ghana, as a case study, this paper analyses the morphological patterns and drivers of urban growth and its impact on wetlands. Data were obtained through remote-sensing, ground truthing, and limited key informant interviews. The analysis combined land use/land cover, building coverage and spatial autoregressive and ordinary least square regression techniques with the aid of ArcGIS version 10.8.2, QGIS version 3.34 and STATA version 17 software. The findings reveal that urban growth at the Ramsar site follows discernible spatial patterns consistent with the spreading pancake, village magnet, and ribbon development models. However, the primary force behind these patterns is growing demand for land to meet housing needs, aided by the failure of state institutions to perform their land use control and wetland protection functions. To achieve sustainable urban development, there is an urgent need to ensure effective wetland management by enforcing existing land use, development control, and wetland protection measures. This calls for the strengthening, resourcing, and closer collaboration of the relationships between the various state agencies responsible for urban planning and wetland management. There is also the need to engage and sensitise political leaders to increase their commitment to implementing wetland protection and pro-environmental policies. Full article

This paper conducts a scientific assessment of aesthetic quality to provide intuitive and scientific planning strategies for national park construction. Focusing on Qianjiangyuan National Park, the study used the scenic beauty evaluation (SBE) method to subjectively assess landscape photos from 16 sample sites. Objective eye movement indicators describing visual behavior were also analyzed. A national park landscape visual quality assessment model was derived through multiple linear regressions correlating subjective evaluations with objective indicators. Spatial technologies like ArcGIS were used to analyze the visual quality and its spatial distribution. Key findings include (1) subjective evaluations showed higher SBE scores for wetland landscapes, followed by recreational, village, and forest landscapes, (2) eye movement behavior varied across landscape types, with the forest landscape having the shortest first fixation time and the lowest saccade frequency, while recreational landscapes had the lowest average saccade speed, (3) strong correlations were found between SBE and indicators such as average fixation time and saccade frequency, with fixation duration ratio being the leading factor influencing visual aesthetic quality, and (4) visual aesthetic quality was highest in the north and south areas of the park, with significant differences between sample sites in these regions compared to the central area. Among different functional zones, the ecological protection area had the highest quality, while the Suzhuang management area excelled in aesthetic quality compared to the Hetian management area. Full article

Land use and land cover changes (LULCCs) are vital indicators for assessing the dynamic relationship between humans and nature, particularly in diverse and evolving landscapes. This study employs remote sensing (RS) data and machine learning algorithms (MLAs) to investigate LULCC dynamics within the Indus River Delta region of Sindh, Pakistan. The focus is on tracking the trajectories of land use changes within mangrove forests and associated ecosystem services over twenty years. Our findings reveal a modest improvement in mangrove forest cover in specific areas, with an increase from 0.28% to 0.4%, alongside a slight expansion of wetland areas from 2.95% to 3.19%. However, significant increases in cropland, increasing from 22.76% to 28.14%, and built-up areas, increasing from 0.71% to 1.66%, pose risks such as altered sedimentation and runoff patterns as well as habitat degradation. Additionally, decreases in barren land from 57.10% to 52.7% and a reduction in rangeland from 16.16% to 13.92% indicate intensified land use conversion and logging activities. This study highlights the vulnerability of mangrove ecosystems in the Indus Delta to agricultural expansion, urbanization, resource exploitation, and land mismanagement. Recommendations include harmonizing developmental ambitions with ecological conservation, prioritizing integrated coastal area management, reinforcing mangrove protection measures, and implementing sustainable land use planning practices. These actions are essential for ensuring the long-term sustainability of the region’s ecosystems and human communities. Full article

Sub-Saharan Africa (SSA) is undergoing rapid urbanization, yet research comparing urban expansion and agricultural land loss in peri-urban areas is scarce. This study utilizes multi-temporal Landsat imagery to examine the impact of urban growth on agricultural land and fragile ecosystems in Kampala (a mega city) and Mbarara (a regional urban center) in Uganda. We distinguish between random and systematic land-use and land-cover (LULC) transitions in the landscape. The results reveal substantial urban expansion. Kampala’s urban area surged from 7.14% in 1989 to 55.10% in 2015, while Mbarara increased from 6.37% in 2002 to 30.95% in 2016. Correspondingly, agricultural land decreased, from 48.02% to 16.69% in Kampala, and from 39.92% to 32.08% in Mbarara. Notably, a significant proportion of urban growth in both cities encroached upon agricultural land (66.7% in Kampala and 57.8% in Mbarara). The transition from agricultural to built-up areas accounted for 14.72% to 28.45% of the landscapes. Additionally, unsustainable practices led to the conversion of wetlands and forests to agricultural land, with approximately 13% of wetlands and 23% of Savannah and forests being converted between 2001 and 2015. These findings underscore the necessity of monitoring LULC changes for sustainable urban growth management, emphasizing the importance of preserving agricultural land and ecosystems to ensure present and future food security. This research contributes to the understanding of urbanization’s impact on peri-urban agricultural land and ecosystems in SSA, providing insights that are crucial for informed urban planning and policy formulation aimed at sustainable development in the region. Full article

As one of the most important ecosystems, the water body is losing water during the rapid development of the city. To understand the impacts on water body change during the rapid urbanization period, this study combines data from the OpenStreetMap platform with Landsat 5/Thematic Mapper images to effectively and accurately identify small urban water bodies. The findings indicate that the trained U-net convolutional neural network (U-Net) water body extraction model and loss function combining Focal Loss and Dice Loss adopted in this study demonstrate high precision in identifying water bodies within the main urban area of Hangzhou, with an accuracy rate of 94.3%. Trends of decrease in water areas with a continuous increase in landscape fragmentation, particularly for the plain river network, were observed from 1985 to 2010, indicating a weaker connection between water bodies resulting from rapid urbanization. Large patches of water bodies, such as natural lakes and big rivers, located at divisions at the edge of the city are susceptible to disappearing during the rapid outward expansion. However, due to the limitations and strict control of development, water bodies, referring to as wetland, slender canals, and plain river networks, in the traditional center division of the city, are preserved well. Combined with the random forest classification method and the U-Net water body extraction model, land use changes from 1985 to 2010 are calculated. Reclamation along the Qiantang River accounts for the largest conversion area between water bodies and cultivated land, constituting more than 90% of the total land use change area, followed by the conversion of water bodies into construction land, particularly in the northeast of Xixi Wetland. Notably, the conversion of various land use types within Xixi Wetland into construction land plays a significant role in the rise of the carbon footprint. Full article

This study develops a structure for mapping native vegetation in a transition area between the Brazilian Cerrado and the Atlantic Forest from integrated spatial information of Sentinel-1 and Sentinel-2 satellites. Most studies use integrated data to improve classification accuracy in adverse atmospheric conditions, in which optical data have many errors. However, this method can also improve classifications carried out in landscapes with favorable atmospheric conditions. The use of Sentinel-1 and Sentinel-2 data can increase the accuracy of mapping algorithms and facilitate visual interpretation during sampling by providing more parameters that can be explored to differentiate land use classes with complementary information, such as spectral, backscattering, polarimetry, and interferometry. The study area comprises the Lobo Reservoir Hydrographic Basin, which is part of an environmental conservation unit protected by Brazilian law and with significant human development. LULC were classified using the random forest deep learning algorithm. The classifying attributes were backscatter coefficients, polarimetric decomposition, and interferometric coherence for radar data (Sentinel-1), and optical spectral data, comprising bands in the red edge, near-infrared, and shortwave infrared (Sentinel-2). The attributes were evaluated in three settings: SAR and optical data in separately settings (C1 and C2, respectively) and in an integrated setting (C3). The study found greater accuracy for C3 (96.54%), an improvement of nearly 2% compared to C2 (94.78%) and more than 40% in relation to C1 (55.73%). The classification algorithm encountered significant challenges in identifying wetlands in C1, but performance improved in C3, enhancing differentiation by stratifying a greater number of classes during training and facilitating visual interpretation during sampling. Accordingly, the integrated use of SAR and optical data can improve LULC mapping in tropical regions where occurs biomes interface, as in the transitional Brazilian Cerrado and Atlantic Forest. Full article