Wetland habitats supporting waterbird diversity: Conservation perspective on biodiversity-ecosystem functioning relationship

Mechanisms of Soil Microbial Community Adaptation in Cold-Region Wetlands Under Retrogressive Succession

Retrogressive succession alters soil conditions and microbial community dynamics in cold-region wetlands, yet its ecological implications remain understudied. This study explored the structure and function of soil microbial communities across three successional stages: swamp (SP), swamped meadow (SM), and meadow (MW). High-throughput 16S rRNA gene sequencing identified 2852 operational taxonomic units (OTUs), with 1682 shared among all stages (58.85%). Alpha diversity indices, including Shannon, Chao, ACE, and Sobs, were significantly higher in MW, with the Shannon index increasing by approximately 32% compared to SP, indicating enhanced richness and evenness. In contrast, Simpson and Coverage indices were highest in SP. Proteobacteria, Actinobacteriota, and Acidobacteriota were dominant phyla, showing distinct distributions across stages. Beta diversity analysis (PCoA and NMDS) revealed clear separation of microbial communities. Soil organic carbon (SOC), pH, soil water content (SWC), cation exchange capacity (CEC), and bulk density (BD) significantly influenced microbial composition and distribution. Functional prediction using FAPROTAX and BugBase indicated a shift from anaerobic metabolism, nitrogen fixation, and cellulolysis in the SP to aerobic chemoheterotrophy and stress tolerance in MW. These results demonstrate that microbial communities adapt to changing soil environments during retrogressive succession, highlighting their role in ecosystem function and resilience in cold-region wetlands.

Ecological network degradation and conservation prioritization analysis of red-crowned crane habitats: a multi-model approach

The loss of coastal wetlands and the degradation of their ecological functions have posed a serious threat to the habitats of global migratory waterbirds, particularly the red-crowned cranes (Grus japonensis). Exploring dynamic changes in the habitat of this flagship species is essential for conserving waterbird diversity and improving wetland ecosystem functions. Therefore, using the Yancheng Biosphere Reserve (YBR)-the largest overwintering site for red-crowned cranes along the East Asian-Australasian Flyway-as a case study, we expanded beyond traditional habitat suitability assessments to include ecological networks, establishing a comprehensive evaluation framework. Specifically, we first enhanced the Habitat Suitability Index (HSI) by incorporating a fuzzy analytic hierarchy process based on the habitat preferences of red-crowned cranes. Ecological corridors were then extracted using the Minimum Cumulative Resistance (MCR) model and their importance was prioritized through a combination of gravity models and landscape connectivity indices. Additionally, circuit theory was employed to identify critical stepping stones and delineate key regions for protection. Our results demonstrated that the current ecological network exhibits poor stability and connectivity, characterized by the fragmentation and loss of ecological sources, degradation and breakup of ecological corridors, and increasing risks to stepping stones. Specifically, during 1991-2022, the total area of ecological sources significantly decreased from 1161.98 km2 to 221.81 km2, and the ecological sources in the southern YBR entirely loss after 2013. Optional low-importance, weak-connectivity corridors largely disappeared, while a few single high-importance, strong-connectivity corridors gradually emerged in their place, as a result of largely decreasing of key ecological corridors from 43 to 15. The proportion of stepping stones associated with natural wetlands decreased from 55.47 % to 38.37 %, accompanied by a reduction in area of the northern YBR. Based on the above analysis, we proposed three categories of conservation areas, aiming to bolster wetland conservation efforts and enhance waterbird biodiversity.

Soil Bacterial Community Characteristics and Functional Analysis of Estuarine Wetlands and Nearshore Estuarine Wetlands in Qinghai Lake

Qinghai Lake, the largest inland saline lake in China, plays a vital role in wetland carbon cycling. However, the structure and function of soil bacterial communities in its estuarine and nearshore estuarine wetlands remain unclear. This study examined the effects of wetland type and soil depth on bacterial diversity, community composition, and functional potential in the Shaliu, Heima, and Daotang River wetlands using high-throughput sequencing. The results showed that wetland type and soil depth significantly influenced bacterial communities. Nearshore wetlands exhibited lower bacterial diversity in the 0-10 cm layer, while deeper soils (10-20 cm) showed greater regional differentiation. Estuarine wetlands were enriched with Proteobacteria, Actinobacteriota, and Chloroflexi, whereas nearshore wetlands were dominated by Actinobacteriota and Cyanobacteria. Functionally, estuarine wetlands had higher sulfate reduction and anaerobic decomposition potential, with Desulfovibrio, Desulfobacter, and Desulfotomaculum regulating sulfur cycling and carbon decomposition. In contrast, nearshore wetlands showed greater nitrogen fixation and organic matter degradation, facilitated by Rhizobium, Azotobacter, Clostridium, and nitrogen-fixing Cyanobacteria (e.g., Anabaena, Nostoc). Microbial metabolic functions varied by depth: surface soils (0-10 cm) favored environmental adaptation and organic degradation, whereas deeper soils (10-20 cm) exhibited lipid metabolism and DNA repair strategies for low-oxygen adaptation. These findings highlight the spatial heterogeneity of bacterial communities and their role in biogeochemical cycles, providing insights into wetland carbon dynamics and informing conservation strategies.

Waterbird community response to wetland and climate changes in the Liaohe River Estuary wetlands, China

The Liaohe River Estuary (LRE) wetland is a critical stopover on the East Asian-Australasian Flyway (EAAF), vital to coastal ecological balance and biodiversity. However, the drivers of changes in waterbird diversity remain unclear. This study utilised random forests to produce reliable time-series wetland mapping from 2010 to 2023. Spatial and temporal changes in wetlands and landscape structures were analysed using landscape pattern indices-the Alpha and Beta diversity analyses were based on monitoring records that assessed waterbird diversity and community structure. The response of waterbirds to wetland, landscape, and climate changes was quantified using a Generalized Linear Mixed Effects Model (GLMM). Between 2010 and 2023, 78 species of waterbirds from 8 orders and 14 families were recorded. In 2023, waterbird counts reached 1,014,908, marking an increase of 868,102 compared to 2010. Over 14 years, waterbird diversity consistently increased, with community structure becoming more stable. Positive responses to climatic factors, such as seasonal precipitation and mean temperatures (both year and seasonal), were observed, while extreme weather inhibited recovery, like heavy precipitation and strong winds. Changes in Suaeda salsa (Sua) and forested areas significantly impacted waterbird diversity compared to other land cover types. These findings highlight the strong influence of climate, wetland, and landscape changes on waterbird diversity and community structure. Managers are encouraged to prioritise monitoring temperature, precipitation, Sua, and forested landscapes while enhancing artificial wetland management to support waterbird diversity and ecological balance in the LRE.

Trends in the Application of Citizen Science in Waterbird Conservation: A Bibliometric Analysis

Waterbirds serve as indicator species for the quality and health of wetland ecosystems, and their conservation is of critical significance for global biodiversity. Citizen science has gradually emerged in recent years, playing an increasingly positive role in scientific research, particularly in ornithological studies. However, a systematic description of the application of citizen science data in waterbird conservation remains lacking. Bibliometrics is an effective method for analyzing the development of scientific disciplines, exploring trends, and examining thematic evolution. This paper utilizes bibliometric analysis of citation data from the Web of Science database, covering the period from 1970 to September 2024. The analysis reveals that this research field has undergone three distinct developmental phases, with a significant increase in annual publication volume during the third phase. Research focus has shifted from specific species and types of waterbirds to key hotspots and ecological phenomena. Future research hotspots are expected to include migratory birds, China, citizen science, and biodiversity. Influential papers within the field emphasize that the primary focus of waterbird conservation is habitat protection and the construction of habitat networks. As the discipline has developed, there is growing recognition that increasing public awareness of waterbird conservation, starting with student education, plays a crucial role in the accumulation of citizen science data and the advancement of waterbird conservation efforts.

How a constructed wetland within a natural park enhances plankton communities after more than 10 years of operation: Changes over space and time

Constructed wetlands are increasingly used as a solution to treat polluted water in natural environments. Located in the Albufera de València Natural Park, a constructed wetland was built in 2009 as a pilot project to act as an intermediary between low-quality waters and the largest protected coastal lagoon in the Iberian Peninsula. With a unique dataset spanning more than a decade (2009-2023), this study assessed changes in plankton communities both spatially (comparing six sampling sites) and temporally (comparing four periods of years). The results show how the constructed wetland, after nearly 15 years of operation, has not only maintained but also improved its capacity to enhance the biological quality of the water which is released into the protected lagoon, thus fulfilling one of the main aims of its construction. During the last period (2020-2023) of the time series, the constructed wetland outlets had significantly higher zooplankton biomass, particularly filter-feeding cladocerans, compared to the inlets. This clear improvement in the plankton community was due to management interventions (e.g., drying sectors of the constructed wetland during the summers since 2019) and the rise in temperature. These circumstances promoted earlier hatching of cladoceran diapause eggs from the sediments compared to previous years, maintaining their presence throughout all seasons. Consequently, the outlets of the constructed wetland had significantly lower phytoplankton abundance and sestonic chlorophyll-a concentrations than in the past, nearly oligotrophic states, and a reduced biovolume of potentially toxic cyanobacteria in the released waters.

The taxonomic, functional and phylogenetic diversity of birds in Xiaohongxiang Wetland, southwest China

Small wetlands are essential for preserving global biodiversity, yet they are frequently neglected in conservation strategies due to vague definitions and a lack of research attention. In this study, we conducted thirty-six surveys via the point count method in the Xiaohongxiang Wetland, Anning City, Yunnan Province, China, from November 2023 to June 2024. We aimed to evaluate the impact of various habitats surrounding Xiaohongxiang Wetland (wetlands, villages, farmlands, cherry plantations and pine forests) on the taxonomic, functional and phylogenetic diversity of avian species and investigate the significance of these habitats for ecological conservation and restoration efforts. A total of 62 species were recorded. Small wetlands are vital for supporting common waterbirds, but may not safeguard rare species effectively. While cherry plantations and pine forests enhance avian diversity near wetlands, their low functional diversity could limit the ecological niches available to birds. This indicates that monoculture plantations might restrict the habitat variety needed for a diverse bird community. Our study found no clear phylogenetic clustering or overdispersion amongst bird species across habitats, suggesting that community assembly is shaped by competitive exclusion, habitat filtering and neutral processes. Despite a limited sample size, our results highlight a gap between taxonomic and functional diversity, indicating that multidimensional biodiversity metrics are essential for thoroughly evaluating wetland restoration and habitat impacts on bird diversity.

Ecosystem health assessment of East Kolkata Wetlands, India: Implications for environmental sustainability

The East Kolkata Wetlands (EKW) in Kolkata, India, span 12,500 ha and are a vital ecological zone providing several benefits, including water purification, flood control, and biodiversity support. This study investigated land use and land cover (LULC) alterations in the EKW from 1991 to 2023, using a random forest (RF) machine learning model. Significant LULC changes were observed over the 32 years, with wetland areas decreasing from 91.2 km2 in 1991 to 33.4 km2 in 2023, reflecting substantial habitat loss and reduced ecosystem services. Conversely, agricultural land expanded from 27.8 km2 to 58.7 km2, driven by economic and food production needs, and built-up areas increased dramatically from 0.2 km2 to 10.5 km2, indicating rapid urbanization. This study evaluated the health, resilience, and ecosystem functionality of EKW by analysing human-induced land use changes and using ecological indicators and landscape metrics. Landscape and class level metrics such as PLAND, largest patch index (LPI), total edge (TE), edge density (ED), number of patches (NP), and patch density (PD) were used to analyse the spatiotemporal dynamics of the wetlands. This study revealed a significant increase in fragmentation, with the number of patches increasing from 2689 in 1991 to 4532 in 2023, despite a consistent decrease in core wetland areas. Ecosystem health indicators, such as the ecosystem structure index (ESI) and landscape deviation degree (LDD), were used to assess landscape metrics and fragmentation changes. The ESI and other metrics revealed significant temporal fluctuations, providing insights into landscape structure, connectivity, and heterogeneity. The ESI improved from 0.87 in 1991 to 1.03 in 2023, indicating enhanced connectivity and diversity. Conversely, the LDD increased from 20.6% to 56.85%, indicating a shift towards impervious surfaces. The vegetation productivity and ecosystem health index (EHI) decreased, indicating biodiversity loss and reduced carbon sequestration. The EHI also dropped from 0.67 to 0.55, signifying ongoing environmental stress. This study emphasizes the need for conservation efforts to maintain the ecological integrity of the EKW amidst urbanization and land use changes and recommends a balanced approach for sustainable urban development and enhanced wetland resilience.