Comparison of avian biodiversity and community similarity between Nansihu wetland and the Yellow River Delta wetland across different seasons.

Comparison of avian biodiversity and community similarity between Nansihu wetland and the Yellow River Delta wetland across different seasons - PMC Skip to main content An official website of the United States government Here's how you know Here's how you know Search Log in Primary site navigation Search Log in Search PMC Full-Text Archive Search in PMC Journal List User Guide As a library, NLM provides access to scientific literature. Inclusion in an NLM database does not imply endorsement of, or agreement with, the contents by NLM or the National Institutes of Health. Learn more: PMC Disclaimer | PMC Copyright Notice BMC Zool . 2026 May 12;11:18. doi: 10.1186/s40850-026-00268-0 Comparison of avian biodiversity and community similarity between Nansihu wetland and the Yellow River Delta wetland across different seasons Yuewei Yang 1, 2, ✉, # , Xingjia Zheng 1, 2, # , Lingyue Lv 3 , Fengfei Sun 1, 2 , Wei He 1, 2 , Yi Li 3, ✉ Author information Article notes Copyright and License information 1 School of Life Sciences, Qufu Normal University, Qufu, Shandong Province 273165 China 2 Shandong Key Laboratory of Wetland Ecology and Biodiversity Conservation in the Lower Yellow River, Qufu, Shandong Province 273165 China 3 Shandong Academy for Environmental Planning, Jinan, 250101/250102 China ✉ Corresponding author. # Contributed equally. Received 2026 Mar 6; Accepted 2026 May 4; Collection date 2026. © The Author(s) 2026 Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/ . PMC Copyright notice PMCID: PMC13227624  PMID: 42121213 Abstract Birds are widely recognized as important bioindicators, particularly in wetland ecosystems that support high biodiversity. This study investigated the structure and seasonal dynamics of bird communities in the Nansi Lake wetland and the Yellow River Delta wetland in Shandong Province, China. Bird surveys were conducted using the point count method, and species diversity, richness, evenness, and abundance were analyzed. A total of 220 bird species (347,599 individuals) were recorded across the two wetlands. The results revealed clear differences in community structure between the wetlands, with the Yellow River Delta consistently supporting higher species diversity, particularly in spring and summer, while the Nansi Lake wetland exhibited lower diversity during autumn and winter. Seasonal variation significantly influenced bird abundance and community composition, with stronger differences between the wetlands observed during the wet season. In addition, species similarity was generally higher in the Yellow River Delta wetland, indicating a more stable community structure across seasons. These findings suggest that habitat characteristics and seasonal environmental changes jointly shape bird community dynamics in coastal and inland wetlands. Overall, this study highlights the importance of seasonal processes in structuring wetland bird communities and provides a scientific basis for the conservation and management of wetland-dependent bird species in eastern China. Supplementary Information The online version contains supplementary material available at 10.1186/s40850-026-00268-0. Keywords: Bird species, Relative abundance, Species diversity, Community similarity Introduction Wetlands are among the most biologically productive ecosystems on Earth, providing critical ecological functions such as water purification, flood regulation, carbon storage, and biodiversity conservation [ 37 , 38 , 78 ]. As globally distributed but highly vulnerable ecosystems, wetlands are widely recognized as “the kidneys of the Earth” due to their essential role in maintaining environmental stability and ecosystem services [ 7 ]. However, rapid urbanization, land reclamation, and climate change have led to significant wetland degradation and habitat loss worldwide, resulting in severe declines in biodiversity, particularly among wetland-dependent species [ 61 ]. Biological resources are an indispensable and important part of human survival and are vital to the development of human society and the building of an ecological civilization [ 42 ]. However, in recent years, with the expansion of the scope of human activities and the rapid increase in the ability of human beings to transform nature, the natural landscapes of wetlands and other areas have been altered as a result of over-exploitation by human beings, and the diversity of wildlife, especially birds, has declined significantly as a result of the reduction of suitable habitats [ 55 ]. Birds are widely recognized as effective bioindicators of ecosystem health due to their sensitivity to environmental change, wide distribution, and ease of monitoring [ 8 , 76 ]. In wetland ecosystems, bird community structure, species diversity, and abundance patterns are frequently used to assess habitat quality and ecological status [ 64 ]. Previous studies across different regions have demonstrated that wetland bird communities are strongly influenced by habitat heterogeneity, food availability, and seasonal environmental fluctuations [ 27 , 54 , 57 ]. For instance, research in South American wetlands has shown that waterbird assemblages respond strongly to hydrological changes and nutrient availability, influencing both species richness and functional diversity [ 5 ]. Similarly, studies have revealed that landscape configuration and wetland connectivity play key roles in structuring bird communities [ 10 , 29 ]. In recent decades, global research has increasingly focused on the ecological drivers of bird community dynamics in wetland ecosystems. For example, research in European and North American wetlands has emphasized the role of hydrological regimes and landscape structure in shaping bird assemblages, while studies in Asia have increasingly focused on the impacts of human disturbance and habitat fragmentation [ 12 , 32 ]. Seasonal variation, in particular, has been identified as a critical factor influencing species composition, migration patterns, and resource use. And a study in Argentina have reported significant seasonal shifts in bird abundance linked to water level fluctuations and food resource availability [ 45 ]. Likewise, investigations in the eastern United States have demonstrated that migratory bird diversity peaks during transitional seasons, reflecting the importance of wetlands as stopover and wintering habitats [ 28 ]. In China, wetland bird diversity has been extensively studied in several ecologically important regions, including the Yangtze River floodplain, Poyang Lake, and coastal wetlands of the Yellow Sea [ 20 , 23 , 28 ]. Certain studies have also highlighted the influence of habitat heterogeneity, human disturbance, and seasonal hydrological changes on bird community structure. For example, research in Poyang Lake has shown that water level fluctuations significantly affect the distribution and abundance of wintering waterbirds [ 79 ], while studies in the Yellow River Delta have emphasized the importance of coastal wetlands for migratory species along the East Asian-Australasian Flyway [ 83 ]. Seasonal variation plays a fundamental role in shaping bird assemblages, influencing species migration, breeding behavior, and habitat use [ 36 ]. Understanding how bird communities respond to seasonal changes across different wetland types is crucial for biodiversity conservation and ecosystem management, particularly in the context of increasing environmental pressure. The Nansi Lake wetland, the largest freshwater lake system in northern China [ 87 ], and the Yellow River Delta wetland, a representative coastal wetland, are both key habitats for diverse bird communities [ 13 ]. These wetlands differ markedly in hydrological conditions, vegetation structure, and degrees of human disturbance, which may lead to distinct patterns in bird community composition and seasonal dynamics. However, despite their ecological importance, comparative studies examining bird diversity and community structure between inland lake wetlands and coastal delta wetlands under a unified seasonal framework remain scarce. The number of species occurring in different seasons is a difference between bird assemblages, and wetland managers should be extremely concerned about the dramatic loss of species diversity and the seasonal persistence of dominant assemblages. Therefore, the objectives of this study are to: (1) investigate the seasonal variation in bird species diversity and community structure in the Nansi Lake (NSH) and Yellow River Delta (YRD) wetlands; (2) compare differences in species richness, abundance, and diversity between inland and coastal wetland ecosystems; and (3) provide a scientific basis for wetland bird conservation and management in eastern China. Materials and methods The study areas The Nansi Lake (NSH) belongs to the Huaihe River basin, with a basin area of 31,700km 2 (Kugarajah et al.,), located at the junction of Shandong Province, Henan Province, Jiangsu Province and Anhui Province. Among them, the upper lake is 27,573km 2 and the lower lake is 4,127km 2 , with an area of 25,700km 2 within the territory of Shandong Province, which mainly flows through the four regions of Zaozhuang, Heze, Tai’an and Jining [ 40 ]. NSH is the largest freshwater lake in northern China, consisting of four tandem lakes, namely Nanyang Lake, Dushan Lake, Zhaoyang Lake, and Weishan Lake [ 43 ], geographically situated between longitude 116°34′~117°21′E and latitude 34°27′~35°20′N, with long and narrow shapes. Nansi Lake Provincial Nature Reserve includes the entire NSH and its beachland, surrounding farmland, mountains and forests. The lake area is an important habitat and breeding ground for many rare and endangered birds, and is also an important place for migratory birds to migrate and take a rest in spring and autumn [ 44 ]. The distribution area of wetland biodiversity and more than 95% of rare and endangered bird habitats are in the core area and buffer zone, which are the habitats of many freshwater birds. Nansi Lake Provincial Nature Reserve has a high density of higher plants, high ecological quality of vegetation and a large area effectiveness of wetlands. Bordered by the Bohai Sea to the north and Laizhou Bay to the east, the Yellow River Delta (YRD) is one of the largest deltas in China [ 89 ], with geographic coordinates ranging from 117º31´E~119º18º31´E to 36º55º31´ N ~ 38º16º31´N. YRD is the most complete and extensive new wetland ecosystem in China’s warm-temperature zone [ 85 ]. Covering an area of 5450 km², the YRD has complex and diverse wetland types due to the influence of freshwater and the sea, and is the most extensive and concentrated area of warm-belt wetlands in China, rich in terrestrial, oil and gas, biological, marine and warm-temperate climate resources [ 81 ]. YRD is not only an ecological functional area for biodiversity conservation that plays an important role in national ecological security, but also an irreplaceable and important ecological region in China and even in the world [ 58 ]. In 2013, YRD was approved by the Secretariat of the Convention on Wetlands of International Importance to be included in the List of Wetlands of International Importance [ 90 ], with a total area of 457,000 hectares of wetlands, rich wetland resources, accounting for about one-quarter of the total area of wetlands in Shandong Province, and a total area of 153,000 hectares of national nature reserves, providing important habitats for a variety of rare birds. With a total area of 153,000 hectares, it provides an important habitat for many kinds of rare birds, and is an important ‘transit, wintering and breeding ground’ for birds migrating from the inland rivers of Northeast Asia to the Western Pacific Rim, and is also an important place for the protection of species, migration of migratory birds, and research on ecological succession in estuaries [ 46 ]. For example, many nationally protected birds winter and breed in the Yellow River Delta Nature Reserve (YRDNR), including the Saunders’s Gull ( Chroicocephalus saundersi ), Red-crowned Crane ( Grus japonensis ) and Oriental Stork( Ciconia boyciana ) [ 91 ]. The number of bird species in the reserve has increased from 283 in 2000 to 368 today, with 38 species exceeding 1% of the global average population. Both wetlands have a temperate continental monsoon climate with four distinct seasons and a hot wet season. The average annual temperature in the YRD is 11.7–12.6 °C. The average annual precipitation is 530–630 mm, of which 70% is concentrated in summer. The annual evaporation is 1900–2400 mm [ 53 ]. NSH annual average temperature of 14.2 ℃, 13.7 ℃ along the lake land, the average annual rainfall of 624 mm, precipitation seasonal changes are significant, and flood season rainfall accounted for 60–70% of the annual rainfall [ 63 ]. In recent decades, both regions have experienced increasing temperatures and changes in precipitation patterns, consistent with broader climate change trends in eastern China. Annual mean temperature has shown an increasing trend, while precipitation variability has increased, with more frequent extreme events. These climatic changes may influence wetland hydrology and subsequently affect bird community dynamics. Methods Data were collected in the NSH wetland and the YRD wetland during the periods of June 2022 to May 2023 and January 2023 to December 2023, respectively, and were classified into spring (March to May), summer (June to August), autumn (September to November), and winter (December to February), and into dry (September to December and January to May) and wet (June to August) seasons [ 75 , 92 ]. In order to ensure data completeness, the surveys covered each season evenly, all surveys were conducted using a standardized point count protocol to investigate the structure and diversity of bird assemblages in the study area. Although the sampling periods of the two wetlands were not completely synchronized, both covered a full annual cycle, allowing for seasonal comparisons. When the sample point method was used to conduct a survey, with the help of monoculars and binoculars, with the point as the center, record the occurrence of birds within a radius of 50 m from the sample point, and directly count the species and number of birds within a certain area. To prevent duplication of bird counts, the spacing between each observation point was greater than or equal to 200 m. In order to reduce the interference in the process of point counting, wait for 5 min before counting to make preparations and adjustments to the birds, and carry out bird observation of each point for not less than 15 min [ 6 ]. Data were collected between 06:00 to 09:00 in the morning and 15:00 to 17:00 in the afternoon, when bird activities were most active [ 19 ]. During surveys, bird calls can be recorded to be used later for identification, and the time and weather of the sampling cycle can be recorded during the bird adjustment phase. Bird species were identified in the field using standard ornithological references, primarily a field guide to the birds of China [ 47 ]. Taxonomy and nomenclature of all recorded species were standardized according to the IOC World Bird List. Photographs of birds were taken with a digital camera for greater certainty. Bird sounds were also used for identification. 25 sample points were deployed in the wetland of NSH wetland, while 18 sample points were deployed in the wetland of the YRD, and the survey points were set up randomly at moderate distances. To account for differences in sampling effort between the two wetlands, rarefaction analysis was conducted to standardize species richness. The locations of each survey point are shown in Fig. 1 . Fig. 1. Open in a new tab A study area map Data analysis All the recorded bird species were analyzed using various parameters like the Species Diversity Index (H’), species evenness (E), species abundance, and richness [ 26 ]. The number of individuals recorded for each bird species was evaluated using the Species Diversity Index (H’). The more evenly distributed the individuals are among the species, the greater the value of the index. The diversity index is largest if each individual belongs to a different species and smallest if each individual belongs to the same species. The formula is as follows: Where H’ is the diversity index, P i is the proportion of each species in the sample, and S is the number of bird species that make up the community. The average density of bird species in the study area was calculated as the proportion of individuals of a given species relative to the total number of individuals recorded (Abramova, [ 1 ]): One of the most commonly used measures of uniformity is the Simpson’s Uniformity Index. Simpson’s uniformity index is defined as: Where H’ and S are as above and H max should refer to the theoretical maximum value of the Shannon Index when individuals in the community are evenly distributed among all species. Richness: The number of species per sample is a measure of richness. The more species present in a sample, the richer the sample becomes. The Margalef Index is used as a simple measure of species richness [ 70 ]. Where S is the total number of species, N is the total number of individuals in the sample, and ln is the natural logarithm. To evaluate bird species variation between habitats in the dry and wet seasons, a one-way ANOVA test was employed. The similarity among sites and seasons in terms of bird species composition was evaluated using the Similarity Index (SI) [ 35 ]. Where SI denotes the similarity index, A represents the number of species recorded at site A, B represents the number of species recorded at site B, and C represents the number of species shared by both sites. Species numbers were directly obtained from field survey data. The SI was calculated based on species presence-absence data. Differences in bird abundance or density between habitats and seasons were analyzed using one-way analysis of variance (ANOVA). A significance level of 0.05 was applied in all statistical analyses. In the ANOVA, habitat type (NSH vs. YRD) was treated as the independent variable, and bird abundance or density was treated as the dependent variable. Each survey sample (sampling site or survey unit) was considered as an independent replicate. Bird abundance data were log-transformed prior to analysis to improve normality and homogeneity of variances. ANOVA was then performed on the transformed data. In addition, a non-parametric Kruskal-Wallis test was conducted to verify the robustness of the results. Results Comparison of bird species diversity in four seasons in NSH and YRD wetlands The rarefaction curves (Fig. 2 ) show the species richness patterns of NSH wetland and YRD wetland as sampling effort increases. The curves indicate that while both wetlands exhibit increasing species richness with the number of individuals sampled, the YRD wetland reaches a higher plateau at a lower sampling intensity compared to the NSH. These results suggest that, after standardizing for sampling effort, the species richness of the two wetlands can be compared on an equal footing. Fig. 2. Open in a new tab The rarefaction curves of species in NSH and YRD wetlands During the study period, a total of 347,599 individual birds, including 220 species, 17 orders, and 51 families, were recorded in the study area. In NSH and YRD wetlands, a total of 217,945 and 129,654 individual birds were recorded during the four seasons, respectively. During the four seasons of spring, summer, autumn and winter, the NSH wetland recorded 90, 70, 55 and 65 bird species, respectively, while the YRD wetland recorded 163, 120, 151 and 77 bird species, respectively. Overall, more bird species were recorded in the YRD wetland than in the NSH wetland, while more individual birds were recorded in the NSH wetland. Protected animals such as the Baer’s Pochard ( Aythya baeri ), the Dalmatian Pelican ( Pelecanus crispus ), the Red-crowned Crane ( Grus japonensis ) [ 66 ] and the Oriental Stork ( Ciconia boyciana ) were observed in the study area (See the supplementary materials for details) [ 4 , 14 , 33 , 69 ]. The order Passeriformes is represented by the highest number of species ( N = 76), followed by the order Charadriiformes ( N = 53) and Anseriformes ( N = 27), orders Accipitriformes and Pelecaniformes with 14 species each, and there are 10 species in the order Gruiformes. The order Falconiformes includes 6 species and the order Columbiformes includes 4 species. Orders Piciformes and Coraciiform with 3 species each, orders Podicipediformes, Galliformes and Ciconiiformes with 2 species each, and orders Strigiformes, Suliformes, Cuculiformes, Bucerotiformes with a single species each (Fig. 3 ). Order Passeriformes also have the highest number of families ( N = 25), followed by order Charadriiformes ( N = 7) and order Pelecaniformes ( N = 3), orders Accipitriformes and Gruiformes with two families each, and orders Anseriformes, Bucerotiformes, Columbiformes, Podicipediformes, Galliformes, Ciconiiformes, Piciformes, Suliformes, Falconiformes, Coraciiform, Cuculiformes and Strigiformes with a single family each (Fig. 3 ). Fig. 3. Open in a new tab Bird orders and number of species in YRD and NSH wetlands Overall, the number of bird species recorded in the YRD wetland was greater than that in the NSH wetland in all three seasons except winter; while both the maximum (NI max =182,549) and minimum (NI min =7134) numbers of individual birds surveyed occurred in the NSH wetland. Bird abundance in the YRD wetland was higher than that in the NSH wetland in all four seasons. The highest and lowest values of abundance in NSH wetland an YRD wetland were both in spring (RI max =9.023, 16.167) and in winter (RI min =5.283, 7.771). The YRD wetland had higher species diversity in spring (H’ = 3.4894) and summer (H’=3.485) conditions. The NSH habitat, on the other hand, had a lower species diversity in both autumn (H’=1.869) and winter (H’=1.225) conditions. Species evenness in the habitats of the YRD wetland and NSH wetland in the three seasons except winter was the highest in summer, followed in spring, and the lowest in autumn; the difference was that the evenness in winter of the NSH wetland was lower than that in the other three seasons, whereas the YRD wetland had the highest evenness in winter. And the evenness of bird species in the YRD wetland was higher than that in NSH wetland in all four seasons. The highest species evenness (E) was found in the YRD wetland in winter, which was 0.730 (Table 1 ). The orders of birds recorded in the four seasons are shown in Fig. 4 . Table 1. The diversity of bird species in the study area during the wet and dry seasons Wetland Season NS NI RI H’ H’/H max NSH Spring 90 19,215 9.023 2.255 0.501 Summer 70 7134 7.777 2.745 0.646 Autumn 55 9047 5.927 1.869 0.466 Winter 65 182,549 5.283 1.225 0.294 YRD Spring 163 22,479 16.167 3.489 0.685 Summer 120 19,010 12.078 3.485 0.728 Autumn 151 70,497 13.437 2.568 0.512 Winter 77 17,668 7.771 3.172 0.730 Open in a new tab NS=Number of species, NI=Number of individuals, RI=Richness, H’=Shannon-Wiener diversity index, H’/H’ max =Evenness, H’ max =ln(S) Fig. 4. Open in a new tab Seasonal variation in the number of individual birds across different orders Bird species’ similarity between seasons and habitats Simpson’s similarity index (SI) of the bird species in the two wetland habitats indicated that a higher (SI = 0.587) similarity of bird species between the four seasons was observed at the YRD wetland habitat when compared to the NSH wetland (SI = 0.543) (Table 2 ). Bird species showed similarities between the NSH and YRD wetlands. The highest bird species similarity (SI = 0.6338) was found between the NSH wetland and the YRD wetland in winter; the lowest bird species similarity was found in autumn (SI = 0.408). In addition, species similarity between the two wetlands was 0.609 and 0.516 in spring and summer, respectively (Table 3 ). One-way ANOVA revealed significant differences in bird abundance between the two wetlands in both seasons (Table 4 ). During the wet season, bird abundance was significantly higher in the YRD wetland than in the NSH wetland (F = 14.820, P < 0.01). Similarly, in the dry season, bird abundance in the YRD wetland remained significantly higher than that in the NSH wetland, with an even stronger statistical difference (F = 21.540, P < 0.001). Overall, these results indicate that the YRD wetland consistently supports higher bird abundance than the NSH wetland across seasons. Table 2. The overall similarity (SI) of bird species within habitats during the wet and dry seasons Wetland Spring Summer Autumn Winter Common species Similarity index (SI) NSH 90 70 55 65 76 0.543 YRD 163 120 151 77 150 0.587 Open in a new tab Table 3. Comparison of the similarity of bird species’ habitats during the four seasons Wetland Season Spring Summer Autumn Winter Species No SI Species No SI Species No SI Species No SI NSH wetland with YRD 77 0.609 49 0.516 42 0.408 45 0.634 Open in a new tab Table 4. One-way ANOVA test for differences in bird abundance between sites in the dry and wet seasons Season Habitat Species number Mean value (bird abundance) SD F P Wet NSH 70 69.954 10.456 14.820 < 0.01 * YRD 120 119.958 15.235 Total 190 189.959 12.288 Dry NSH 107 106.966 18.380 21.540 < 0.001 ** YRD 194 193.964 25.121 Total 301 300.967 23.467 Open in a new tab Comparison between average density of birds A total of 217,945 and 129,654 individual birds were recorded from the NSH and YRD wetlands in investigation period. The seasonal distribution pattern of the number of individual birds in the NSH wetland was highest in winter ( N = 182,549), followed by spring ( N = 19,215) and autumn ( N = 9047), and lowest in summer ( N = 7134), whereas in the YRD wetland was highest in autumn ( N = 70,497), followed by spring ( N = 22,479), summer ( N = 19,010), lowest in winter ( N = 17,668). In winter, the highest number of individual birds was recorded in the NSH wetland, while lower was recorded in the YRD wetland, which could be attributed to the fact that the NSH wetland is an important wintering site for waterbirds. Meanwhile, when we compared the two wetlands, the maximum and minimum numbers of individual birds both appeared in winter ( N = 182,549) and summer ( N = 7134) of the NSH wetland, whereas the YRD wetland recorded a more homogeneous number of individual birds in the four seasons than the NSH wetland. In general, in all habitats of the present study, bird species abundance during the dry season was high (Fig. 5 ). Additionally, the findings showed that while there was no significant difference in bird density between the two wetlands during the dry season (F = 0.782, P > 0.05), whereas a significant difference was observed during the wet season (F = 4.530, P < 0.05) (Table 5 ). Fig. 5. Open in a new tab Individual (N) bird count in the study habitats Table 5. One-way ANOVA test for differences in bird density between sites in the dry and wet seasons Season Habitat Individual number Mean value (bird density) SD F P Wet NSH 7134 0.033 0.001 4.530 0.041 * YRD 19,010 0.147 0.009 Total 26,144 0.0752 0.014 Dry NSH 210,811 0.967 0.000038 0.782 0.536 YRD 110,644 0.853 0.021 Total 321,455 0.925 0.033 Open in a new tab Discussion Species diversity is a critical indicator in conservation biology, reflecting the health and resilience of ecosystems across various geographical scales [ 48 , 52 , 60 ]. This metric, typically measured by the richness and abundance of species within a habitat, has become a focal point for global biodiversity monitoring and management [ 11 , 56 ]. In previous studies, a total of 215 bird species from 18 orders and 55 families were recorded in Hongze Lake Wetland National Nature Reserve, Sihong, China [ 31 ]; a total of 162 species of birds belonging to 16 orders, 47 families have been recorded in Xinjizhou National Wetland Park, Nanjing, China [ 62 ]. And in worldwide, the Mississippi Alluvial Valley in North America [ 30 ] and the Mekong Delta in Southeast Asia [ 9 ] serve as critical habitats for numerous migratory species. Similar patterns of high avian diversity linked to wetland integrity have also been documented in the Kilombero Valley of East Africa [ 77 ]. In our present study, a total of 220 species of birds from 17 orders and 51 families were recorded, which was similar to the number of orders, families and species of birds recorded in Hongze Lake Wetland National Nature Reserve and Xinjizhou National Wetland Park. This may be due to the fact that they are both on the East Asian-Australian bird migration route. It should be noted that the sampling periods for the two wetlands were not perfectly aligned, which may introduce potential interannual variability (e.g., climatic differences). Therefore, the results should be interpreted with caution when making direct comparisons. The rarefaction analysis highlights the differences in species richness between NSH wetland and YRD wetland. Although the sampling efforts were not perfectly matched, the use of rarefaction curves allows for a fair comparison by standardizing the data. The patterns of species richness suggest that NSH wetland may host a more diverse community in terms of species composition at lower sampling intensities, potentially due to differences in habitat or ecological conditions between the two wetlands. This study showed that the seasonal occurrence of these two wetland bird species was different. In general, most birds were locally common. Bird abundance and species diversity in the YRD wetland were higher than those in the NSH wetland in spring, summer, and autumn. However, in winter, bird abundance in NSH wetland was higher than in the YRD wetland. This seasonal difference may be related to habitat characteristics and resource availability [ 36 ]. For example, coastal wetlands such as the YRD typically provide abundant food resources, including benthic invertebrates and fish, which support higher bird diversity during migration and breeding seasons [ 15 , 41 , 73 ]. In contrast, large inland wetlands such as the NSH wetland may provide more stable open-water habitats during winter [ 16 , 80 ], which are suitable for the aggregation of overwintering waterbirds, particularly large flocks of Anatidae species. Compared with inland wetlands, the YRD wetland also has a larger and more dynamic habitat structure influenced by tidal processes, which may further enhance ecological niches and resource diversity, thereby supporting higher bird abundance and diversity [ 84 , 86 , 88 ]. Differences in bird species composition between wetlands may be due to habitat heterogeneity, bird nesting behavior, resource availability and human disturbance conditions [ 3 , 17 ]. Changes in habitat conditions, wetland area and resource access determine the diversity of bird species in a given environment [ 21 , 25 ]. In winter, the exceptionally high abundance observed in the NSH wetland (> 180,000 individuals) appears to be driven by both the presence of dominant species forming large wintering flocks and favorable habitat conditions. Studies have shown that extensive wetlands with abundant shallow water areas and diverse microhabitats often attract large numbers of migratory waterbirds, particularly Anseriformes and other waterfowl such as Fulica atra , Phalacrocorax carbo , Aythya ferina , Mareca strepera , Mergus merganser and so on, during wintering periods due to available food resources and roosting sites [ 49 , 65 ]. Moreover, environmental factors such as water body extent, vegetation cover, and habitat heterogeneity significantly influence waterbird abundance and habitat selection [ 82 ]. In inland Chinese wetlands, dominant wintering waterbird species often partition resources based on feeding strategies and habitat zones, leading to concentrated aggregations in productive areas [ 34 ]. These ecological mechanisms likely contribute to the peak in bird abundance observed in NSH wetland during winter. The destruction of plant cover, nesting, feeding and breeding habitats, and foraging grounds threatens the survival of birds [ 22 , 50 ], which is consistent with the situation in the NSH wetland. In a similar study around the Lake Dianchi, Yunnan-Guizhou Plateau, bird species diversity in all habitats was highest during the dry season and was lowest in the rainy season in the calendar year, with the lowest species diversity observed in June and July [ 74 ]. Our results showed that in the NSH wetland, the evenness and Shannon-Wiener diversity index of birds were higher in the wet season than in the dry season; in the YRD wetland, the order of evenness of birds was the highest in winter, followed by summer and spring, and the lowest in autumn, while the order of Shannon-Wiener diversity index of birds was the highest in spring, the second highest in summer and winter, and the lowest in autumn. And in both habitats, bird richness was higher in the dry season than in the wet season. There were differences in the number of individuals and species between the two wetlands during the dry and wet seasons. According to Balwan and Kour, wetland habitats provided ample food resources for many bird species [ 7 ], such as frogs, worms and insects. However, in both wetlands, the highest values of species diversity occurred in the YRD wetland. In addition, the presence of multiple habitat types around this wetland may be a contributing factor. Awash and Tekalign described that food resources as one of the key determinants of species diversity in a given area [ 6 ], and the richness of habitat types provides a wide variety of food resources. On the other hand, relatively low bird diversity was observed in the NSH wetland. This pattern may be related to differences in habitat conditions between wetlands. Although previous studies suggest that human activities can negatively affect bird diversity [ 6 ], no direct measurements of human disturbance were conducted in this study, and therefore this factor should be interpreted with caution. In future investigations and studies, we will focus on the interference caused by human factors. The similarity of bird species observed between the two wetlands among four seasons showed to be higher in the YRD wetland, and bird species between the two wetlands in NSH and YRD also showed similarities, with the highest similarity of bird species between the NSH wetland and the YRD wetland in the winter (SI = 0.634), followed by the spring (SI = 0.609) and the summer (SI = 0.516), with lower species similarity in autumn (SI = 0.408). This may be due to the high structural similarity between the two wetlands [ 71 ], and the fact that the climates were more similar during the spring and summer seasons. At the same time, both places are located on the East Asia-Australasia migratory route, and become the wintering grounds for many kinds of waterfowls in winter. These migratory birds move southward to the wetlands of Shandong at lower latitudes due to the cold climate, resulting in a high degree of overlap of bird species between the two sites due to common wintering needs; spring and autumn are the peak migratory seasons, with frequent turnover of bird species and short stopover times, and the two sites may attract different staging populations due to geographical differences (e.g., inland freshwater lakes vs. coastal estuaries), which are diminished by stable wintering populations in winter. Saline habitats in the YRD and freshwater habitats in the NSH differed significantly in spring, summer and autumn, attracting birds of different ecological niches (e.g. coastal plovers vs. freshwater herons). However, the increased salinity tolerance of many bird species in winter, coupled with reduced competitive pressure for food, made cross-habitat use possible. Resident and breeding birds dominated the two sites in spring and summer, but species differentiation was due to geographic isolation; the proportion of resident birds declined in winter, and migratory birds of wide range of fitness became the mainstay, and the similarity increased. The effect of season on bird data was also evident, with significant differences in bird abundance data between the NSH wetland and the YRD wetland in the wet season (F = 14.820, P < 0.01). Similarly, there was significantly higher difference between bird abundance in the two wetland environments in the dry season (F = 21.540, P < 0.001). In addition, the seasonal study of bird density showed the different results as above, with no significant difference in average density between the two wetlands during the dry season (F = 0.782, P > 0.05), whereas a significant difference was observed during the wet season (F = 4.530, P < 0.05). This may indicate that climate such as rainfall, high temperature and wind speed during the wet season had a greater effect on bird species and bird abundance [ 72 ]. Overall, bird species abundance was high during the dry season of this study. The decline in global bird diversity has been linked to a number of anthropogenic factors [ 24 ], including agricultural intensification [ 59 ], habitat segregation, logging and urbanization [ 51 ], global warming and the effects of human land-use changes such as grazing pressure and afforestation [ 39 ]. Bird species occurred in different seasons in the two wetlands and this difference might be due to the availability of food resources, habitat conditions, breeding seasons and migratory behavior of the birds [ 67 ]. Similarly, seasonal changes in food resource abundance led to seasonal changes in bird abundance [ 2 ]. In general, wetlands enable bird populations to persist through complementarity and replenishment of resources, and are important feeding and breeding sites for birds [ 68 ]. Farmers around the wetlands cultivate crops such as maize and wheat in the area. Currently, severe human encroachment has caused the wetlands to shrink in size, resulting in many areas being permanently reclaimed. Ultimately, this may eliminate habitat for birds unless conservation measures are taken by the relevant agencies. However, there were also many birds that we did not record during the survey, which may be due to the fact that birds in open wetland habitats are less visible resulting in poorer visibility [ 18 ]. The two wetlands are inhabited by a large number of birds including many endemic and treasured species, such as Oriental Stork ( Ciconia boyciana ), Baer’s Pochard ( Aythya baeri ), Red-crowned Crane ( Grus japonensis ) and so on. The Ciconiiformes in the NSH wetland only appeared in the spring and were not recorded in the rest of the seasons, which may be due to that the Ciconiiformes pass through southwestern Shandong Province during their spring migration. On the other hand, Gruiformes and Pelecaniformes were not recorded in winter only in the NSH wetland, suggesting that the wintering grounds of them might not be in the NSH wetland. Cuculiformes were found in both wetlands only in summer. Nansi Lake, where the NSH wetland is located, is a freshwater lake, while the YRD is located at the mouth of the Yellow River, which is seawater. Thus the difference in water environment also contributes to the differences in bird data between the two wetlands. In addition to this, the numbers of resident and migratory birds are also quite high, suggesting that the two wetlands are both ideal habitats for resident and migratory birds, as well as important stopover sites along the East Asian-Australian bird migration routes. In order to protect the wetlands and bird populations in the study area and to enhance in-situ conservation of birds, clear signs of conservation areas are to be installed for the habitats of key protected birds adjacent to tourist areas. Attention also needs to be paid to bird behavior and dynamics during the breeding season to control the flow of external visitors and to ensure the safety of birds during the breeding season. As with all ecological studies, our study has some shortcomings in the data collection and analysis process, which we will improve in the upcoming studies. Conclusions The NSH and YRD wetlands have a high bird species diversity since they are home to a variety of bird species. In the present study, bird diversity was studied at all sampling sites in the study area and seasonal variations in bird diversity were observed and described, with differences in bird diversity between seasons. Many treasured bird species were recorded in our surveys, such as the national first-level protected animals Saunders’s Gull ( Saundersilarus saundersi ), Siberian Crane ( Grus leucogeranus ), Hooded Crane ( Grus monacha ), White-naped Crane ( Grus vipio ) and Baer’s Pochard ( Aythya baeri ), etc., and the national second-level protected animals Common Crane ( Grus grus ), Pheasant-tailed Jacana ( Hydrophasianus chirurgus ), Eurasian Skylark ( Alauda arvensis ) and Reed Parrotbill ( Paradoxornis heudei ), etc., which frequently rely on these wetlands. Overall, the number of bird species recorded in the YRD wetland was higher than that in the NSH wetland in all three seasons except winter, and the bird richness and bird species diversity of the YRD wetland were higher than that of the NSH wetland in all four seasons. Bird species diversity during the wet season was generally higher than that during the dry season in both wetlands; bird species diversity during both the wet and dry seasons was higher in the YRD wetland than in the NSH wetland. The larger the wetland area, the higher the bird diversity, which was attributed to the fact that the wetland provided a better habitat for waterbirds and a peripheral plant diversity for land birds. Of the 220 bird species we recorded, the Passeriformes order had the highest number of species with 76. In the current study, the similarity of bird species in the YRD wetland was higher than in the NSH wetland, which had suitable water bodies, denser canopy cover and better bird diversity. Higher similarity of bird species was observed in the YRD wetland than in the NSH wetland during all seasons. There were significant differences in bird density between two wetlands during the wet season and no insignificant differences during the dry season. In contrast to this, there were higher significantly differences in bird abundance of birds between dry season but significant differences between wet season. Different seasons have a strong influence on species richness, and human activities also affect the diversity and abundance of wetland birds. In addition, the presence of diverse waterbird groups, particularly Anatidae and Gruiformes, as well as the co-occurrence of resident and migratory species, may serve as potential indicators of high biodiversity and habitat quality in wetland ecosystems. These findings highlight the importance of maintaining habitat heterogeneity and resource availability to support diverse bird communities. Conservation of all biodiversity, especially bird species, should be a top priority. The conservation of these treasured birds has high ecological and economic values for the protection and restoration of wetland biodiversity. Therefore, it is very important to carry out long-term, systematic and continuous monitoring and tracking studies. Management strategies that emphasize the long-term use of wetlands should be developed in order to learn more about the extent of these impacts and to plan the most effective conservation measures. Accordingly, the development and implementation of conservation initiatives and the establishment of responsible institutions and wetland management policies to protect wetlands in the study area are important. Supplementary Information Below is the link to the electronic supplementary material. Supplementary Material 1 (53.1KB, docx) Supplementary Material 2 (17.8KB, docx) Acknowledgements The authors gratefully thank the financial support provided by the National Natural Science Foundation of China (31672314). Author contributions Y. Y. and X. Z.: Conceptualization, Data Curation, Formal Analysis, Methodology, Software, Visualization, Writing-Original Draft, Investigation, Writing-Review & Editing, Supervision, Validation, Funding Acquisition. F. S. and W. H.: Conceptualization, Methodology, Supervision, Writing-Original Draft, Writing-Review & Editing.L.L. and Y.L.: Data Curation, Formal Analysis, Software. Funding The authors gratefully thank the financial support provided by the National Natural Science Foundation of China (31672314). Data availability We declare that the data supporting the findings of this study are available within the article. Declarations Ethics approval and consent to participate No applicable. Consent for publication Not applicable. Competing interests The authors declare no competing interests. Footnotes Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Yuewei Yang and Xingjia Zheng contributed equally to this work. Contributor Information Yuewei Yang, Email: yangyuewei@163.com. Yi Li, Email: sdsly77@163.com. References 1. Abramova I, The dynamics of bird species abundance during the succession of oak forests in Southwestern Belarus. Zoologichesky Zhurnal. 2022;101(11):1232–42. [ Google Scholar ] 2. Almeida BA, Bochio GM, Calsavara LC, Marques FC, Anjos D, L. Seasonality in niche occupation revealed through bird community functional structure in the southern Atlantic rainforest. Ibis. 2023;165(3):986–97. [ Google Scholar ] 3. Almeida BA, Sebastián-González E, dos Anjos L, Green AJ. Comparing the diversity and composition of waterbird functional traits between natural, restored, and artificial wetlands. Freshw Biol. 2020;65(12):2196–210. [ Google Scholar ] 4. An R, Lu N, Ju H, Li Z, Zelang X, Lu P, Sheng L, Bian H, Guan J. Driving mechanism of iron cycling towards energy recovery and pollutant removal in constructed wetland-microbial fuel cell. J Environ Chem Eng. 2025;13(5):118885. 10.1016/j.jece.2025.118885. [ Google Scholar ] 5. Asmus JP, Romano M, Barberis IM. Hydrological conditions and climatic factors shape waterbird functional diversity in a Ramsar site of Argentina. Ecohydrology. 2025;18(3):e70053. 6. Awash N, Tekalign W. Comparison of bird assemblage structures and diversity patterns between seasons among two Ethiopian wetlands. BMC Zool. 2023;8(1):3. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ] 7. Balwan WK, Kour S. Wetland-an ecological boon for the environment. East Afr Scholars J Agric Life Sci. 2021;4(3):38–48. [ Google Scholar ] 8. Bart J. Monitoring the Abundance of Bird Populations. Auk. 2005;122(1):15–25. 10.1093/auk/122.1.15. [ Google Scholar ] 9. Buckton S. The conservation of key wetland sites in the Mekong Delta. 1999. 10. Buelow CA, Baker R, Reside AE, Sheaves M. Spatial dynamics of coastal forest bird assemblages: the influence of landscape context, forest type, and structural connectivity. Landscape Ecol. 2017;32(3):547–61. [ Google Scholar ] 11. Cardinale BJ, Duffy JE, Gonzalez A, Hooper DU, Perrings C, Venail P, Narwani A, Mace GM, Tilman D, Wardle DA, Kinzig AP, Daily GC, Loreau M, Grace JB, Larigauderie A, Srivastava DS, Naeem S. Biodiversity loss and its impact on humanity. Nature. 2012;486(7401):59–67. 10.1038/nature11148. [ DOI ] [ PubMed ] [ Google Scholar ] 12. Chawaka SN, Mereta ST, Goethals PLM, Lens L, Boets P. Effect of Human-induced Environmental Changes on Bird Diversity and Abundance in Natural Wetlands of Southwest Ethiopia. Waterbirds. 2017;40(2):129–43. 10.1675/063.040.0205. [ Google Scholar ] 13. Chen A, Sui X, Wang D, Liao W, Ge H, Tao J. Landscape and avifauna changes as an indicator of Yellow River Delta Wetland restoration. Ecol Eng. 2016;86:162–73. [ Google Scholar ] 14. Cheng L, Zhou LZ, Yu C, Wei ZH, Li CH. Nest habitat distribution and spatio-temporal dynamics based on multi-scale modeling: Implications for the endangered Oriental Storks (Ciconia boyciana) conservation in China. GLOBAL Ecol Conserv. 2023;43:e02439. 10.1016/j.gecco.2023.e02439. [ Google Scholar ] 15. Choi C-Y, Battley PF, Potter MA, Ma Z, Liu W. Factors affecting the distribution patterns of benthic invertebrates at a major shorebird staging site in the Yellow Sea, China. Wetlands. 2014;34(6):1085–96. [ Google Scholar ] 16. Clair TA, Warner BG, Robarts R, Murkin H, Lilley J, Mortsch L, Rubec C, Koshida G, Avis W. Canadian inland wetlands and climate change. The Canada country study: climate impacts and adaptation. National sectoral volume. Environment Canada, Ottawa, Ontario, Canada. 1998;189–218. 17. Daniel J, Polan H, Rooney RC. Determinants of wetland-bird community composition in agricultural marshes of the Northern Prairie and Parkland Region. Wetlands. 2021;41(1):14. [ Google Scholar ] 18. Derebe Y, Derebe B, Kassaye M, Gibru A. Species diversity, relative abundance, and distribution of avifauna in different habitats within Lewi Mountain, Awi zone, Ethiopia. Heliyon. 2023;9(6):e17127. 10.1016/j.heliyon.2023.e17127. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ] 19. Dessalegn T. Species diversity and abundance of birds of Addis Ababa bole international Airport Master Thesis. Addis Ababa University, Addis Ababa. 2011. 20. Dronova I, Beissinger SR, Burnham JW, Gong P. Landscape-level associations of wintering waterbird diversity and abundance from remotely sensed wetland characteristics of Poyang Lake. Remote Sens. 2016;8(6):462. [ Google Scholar ] 21. Elliott LH, Igl LD, Johnson DH. The relative importance of wetland area versus habitat heterogeneity for promoting species richness and abundance of wetland birds in the Prairie Pothole Region, USA. Condor. 2020;122(1):duz060. [ Google Scholar ] 22. Evans T. Quantifying the global threat to native birds from predation by non-native birds on small islands. Conserv Biol. 2021;35(4):1268–77. [ DOI ] [ PubMed ] [ Google Scholar ] 23. Fan J, Wang X, Wu W, Chen W, Ma Q, Ma Z. Function of restored wetlands for waterbird conservation in the Yellow Sea coast. Sci Total Environ. 2021;756:144061. [ DOI ] [ PubMed ] [ Google Scholar ] 24. Feeley K, Bravo-Avila C, Fadrique B, Perez T, Zuleta D. Climate-driven changes in the composition of New World plant communities. Nat Clim Change. 2020;10(10):965–70. [ Google Scholar ] 25. Gibru A. Species composition, seasonal abundance and distribution of avifauna in Lake Hawassa and part of the Eastern Wetland habitats, Southern Ethiopia. Southern Ethiopia (March 31, 2021). 2021. 26. Goudarzian P, Erfanifard S. The efficiency of indices of richness, evenness and biodiversity in the investigation of species diversity changes (case study: migratory water birds of Parishan international wetland, Fars province, Iran). Biodivers Int J. 2017;1(2):41–5. [ Google Scholar ] 27. Green AJ, Elmberg J. Ecosystem services provided by waterbirds. Biol Rev. 2014;89(1):105–22. [ DOI ] [ PubMed ] [ Google Scholar ] 28. Guo F, Buler JJ, Smolinsky JA, Wilcove DS. Seasonal patterns and protection status of stopover hotspots for migratory landbirds in the eastern United States. Curr Biol. 2024;34(2):235–44. e233. [ DOI ] [ PubMed ] [ Google Scholar ] 29. Haig SM, Mehlman DW, Oring LW. Avian movements and wetland connectivity in landscape conservation. Conserv Biol. 1998;12(4):749–58. [ Google Scholar ] 30. Hokhlova TY, Artemjev AV. Reassessment of the Southern Limit for Whooper Swans Breeding in Northwest Russia. Waterbirds: Int J Waterbird Biology. 2002;25:67–73. http://www.jstor.org/stable/1522336 . [ Google Scholar ] 31. Hu H, Hu W, Xu Z, Lu C. Occurrence dataset of birds in Sihong Hongze Lake Wetlands National Nature Reserve in China. Biodivers. Data J. 2023;11. 10.3897/BDJ.11.e113108. [ DOI ] [ PMC free article ] [ PubMed ] 32. Isaac MM, Muya SM, Kiiru W, Muchai M. Avian Abundance, Diversity and Conservation Status in Etago Sub-County Kisii County Kenya. Open J Ecol. 2019;9(05):157. [ Google Scholar ] 33. Jiao SW, Gungaa A, Lou KX, Wu M, Lei GC, Li YY, Liang W, Jia YF. The current status of the East Asian population of the Dalmatian Pelican (Pelecanus crispus) along the East Asian-Australasian flyway. GLOBAL Ecol Conserv. 2026;65:e04002. 10.1016/j.gecco.2025.e04002. 34. Jinyun C, Zhou L. Guild structure of wintering waterbird assemblages in shallow lakes along Yangtze River in Anhui Province, China. Shengtai Xuebao/ Acta Ecol Sinica. 2011;31:5323–31. [ Google Scholar ] 35. Jokimäki J, Kaisanlahti-Jokimäki ML. Spatial similarity of urban bird communities: a multiscale approach. J Biogeogr. 2003;30(8):1183–93. [ Google Scholar ] 36. Karr JR. Seasonality, resource availability, and community diversity in tropical bird communities. Am Nat. 1976;110(976):973–94. [ Google Scholar ] 37. Kumari R, Shukla SK, Parmar K, Bordoloi N, Kumar A, Saikia P. (2020). Wetlands Conservation and Restoration for Ecosystem Services and Halt Biodiversity Loss: An Indian Perspective. In A. K. Upadhyay, R. Singh, & D. P. Singh, editors, Restoration of wetland ecosystem: a trajectory towards a sustainable environment (pp. 75–85). Springer Singapore. 10.1007/978-981-13-7665-8_6. 38. La Creta KMZ. Avifauna occupancy as an indicator of future wetland condition in Vermont, USA: A Case Study [Dissertation/Thesis]. 2022. 39. Lehikoinen A, Brotons L, Calladine J, Campedelli T, Escandell V, Flousek J, Grueneberg C, Haas F, Harris S, Herrando S, Husby M, Jiguet F, Kålås JA, Lindström Å, Lorrillière R, Molina B, Pladevall C, Calvi G, Sattler T, Trautmann S. Declining population trends of European mountain birds. Glob Change Biol. 2019;25(2):577–88. 10.1111/gcb.14522. [ DOI ] [ PubMed ] [ Google Scholar ] 40. Li C, Zhao J. Investigating the Spatiotemporally Varying Correlation between Urban Spatial Patterns and Ecosystem Services: A Case Study of Nansihu Lake Basin, China. ISPRS Int J GEO-INFORMATION. 2019;8(8):346. 10.3390/ijgi8080346. [ Google Scholar ] 41. Li D, Ding Y, Yuan Y, Lloyd H, Zhang Z. Female tidal mudflat crabs represent a critical food resource for migratory Red-crowned Cranes in the Yellow River Delta, China. Bird Conserv Int. 2014;24(4):416–28. [ Google Scholar ] 42. Li J, Pei Y, Zhao S, Xiao R, Sang X, Zhang C. A review of remote sensing for environmental monitoring in China. Remote Sens. 2020;12(7):1130. [ Google Scholar ] 43. Li J, Yuan G-L, Deng X-R, Jing X-M, Sun T-H, Lang X-X, Wang G-H. Major ion geochemistry of the Nansihu Lake basin rivers, North China: chemical weathering and anthropogenic load under intensive industrialization. Environ Earth Sci. 2016;75:1–16. [ Google Scholar ] 44. Liu H, Jiang Y, Misa R, Gao J, Xia M, Preusse A, Sroka A, Jiang Y. Ecological environment changes of mining areas around Nansi lake with remote sensing monitoring. Environ Sci Pollut Res. 2021;28:44152–64. [ DOI ] [ PubMed ] [ Google Scholar ] 45. Lorenzón RE, Beltzer AH, Olguin PF, León EJ, Sovrano LV, Antoniazzi CE, Ronchi-Virgolini AL. Temporal variation of bird assemblages in dynamic fluvial wetlands: seasonality and influence of water level and habitat availability. Revista de Biología Trop. 2019;67(6):1131–45. [ Google Scholar ] 46. Lu M, Jiang Y. Research progress on the evolution characteristics of wetlands in the Yellow River Delta. Adv Resour Res. 2022;2(3):87–98. [ Google Scholar ] 47. MacKinnon JR, Phillipps K. A field guide to the birds of China. Oxford University Press; 2000. 48. Magurran AE. Measuring biological diversity. Wiley; 2003. [ DOI ] [ PubMed ] 49. Malekian M, Salarpour R, Ranaie M. Wetland characteristics affect abundance and diversity of wintering birds: A case study in South-Western Iran. Ecol Evol. 2022;12(11):e9558. 10.1002/ece3.9558. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ] 50. Maseko MS, Zungu MM, Ehlers Smith DA, Smith E, Y. C., Downs CT. Effects of habitat-patch size and patch isolation on the diversity of forest birds in the urban-forest mosaic of Durban, South Africa. Urban Ecosyst. 2020;23(3):533–42. [ Google Scholar ] 51. Matuoka MA, Benchimol M, de Almeida-Rocha JM, Morante-Filho JC. Effects of anthropogenic disturbances on bird functional diversity: A global meta-analysis. Ecol Ind. 2020;116:106471. [ Google Scholar ] 52. Methorst J, Rehdanz K, Mueller T, Hansjürgens B, Bonn A, Böhning-Gaese K. The importance of species diversity for human well-being in Europe. Ecol Econ. 2021;181:106917. [ Google Scholar ] 53. Miao X, Hao Y, Zhang F, Zou S, Ye S, Xie Z. Spatial distribution of heavy metals and their potential sources in the soil of Yellow River Delta: a traditional oil field in China. Environ Geochem Health. 2020;42:7–26. [ DOI ] [ PubMed ] [ Google Scholar ] 54. Milton W. Wetland bird’s habitat resources and conservation implications. In: United Kingdom: Cambridge University Press; 2003. [ Google Scholar ] 55. Negret PJ, Maron M, Fuller RA, Possingham HP, Watson JE, Simmonds JS. Deforestation and bird habitat loss in Colombia. Biol Conserv. 2021;257:109044. [ Google Scholar ] 56. Newbold T, Hudson LN, Hill SLL, Contu S, Lysenko I, Senior RA, Börger L, Bennett DJ, Choimes A, Collen B, Day J, De Palma A, Díaz S, Echeverria-Londoño S, Edgar MJ, Feldman A, Garon M, Harrison MLK, Alhusseini T, Purvis A. Global effects of land use on local terrestrial biodiversity. Nature. 2015;520(7545):45–50. 10.1038/nature14324. [ DOI ] [ PubMed ] [ Google Scholar ] 57. Peterson AC, Niemi GJ. Evaluation of the Ohio Rapid Assessment Method for wetlands in the western Great Lakes: An analysis using bird communities. J Great Lakes Res. 2007;33:280–91. [ Google Scholar ] 58. Qiu M, Yang Z, Zuo Q, Wu Q, Jiang L, Zhang Z, Zhang J. Evaluation on the relevance of regional urbanization and ecological security in the nine provinces along the Yellow River, China. Ecol Ind. 2021;132:108346. [ Google Scholar ] 59. Rigal S, Dakos V, Alonso H, Auniņš A, Benkő Z, Brotons L, Chodkiewicz T, Chylarecki P, De Carli E, Del Moral JC. Farmland practices are driving bird population decline across Europe. Proc Natl Acad Sci. 2023;120(21):e2216573120. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ] 60. Sala OE, Stuart Chapin F, Armesto JJ, Berlow E, Bloomfield J, Dirzo R, Huber-Sanwald E, Huenneke LF, Jackson RB, Kinzig A, Leemans R, Lodge DM, Mooney HA, Oesterheld Mn, Poff NL, Sykes MT, Walker BH, Walker M, Wall DH. Global Biodiversity Scenarios for the Year 2100. Science. 2000;287(5459):1770–4. 10.1126/science.287.5459.1770. [ DOI ] [ PubMed ] [ Google Scholar ] 61. Salimi S, Almuktar SA, Scholz M. Impact of climate change on wetland ecosystems: A critical review of experimental wetlands. J Environ Manage. 2021;286:112160. [ DOI ] [ PubMed ] [ Google Scholar ] 62. Shen W, Zhao Z, Xu Z, Zhang Y. Occurrence dataset of birds in the Xinjizhou National Wetland Park, Nanjing, China. Biodivers. Data J. 2023;11. [ DOI ] [ PMC free article ] [ PubMed ] 63. Shi H, Lv R, Liu Y, Xiao D, Wang Z, Yuan X, Liu L, Yu C. Spatial Variability Characteristics and Influencing Factors of Soil Fluoride in the Western Nansihu Lake Basin. Water. 2023;15(21):3855. https://www.mdpi.com/2073-4441/15/21/3855 . [ Google Scholar ] 64. Soultan A, Pavon-Jordan D, Bradter U, Sandercock BK, Hochachka WM, Johnston A, Brommer J, Gaget E, Keller V, Knaus P. The future distribution of wetland birds breeding in Europe validated against observed changes in distribution. Environ Res Lett. 2022;17(2):024025. [ Google Scholar ] 65. Squalli W, Mansouri I, Douini I, Achiban H, Saghrouchni H, El Agy A, Fadil F, Wink M, Dakki M. Diversity and Population Sizes of Wintering Waterbirds in the Wetlands of the Saïss–Middle Atlas Region (North–Central Morocco): Main Survival Factors and Evaluation of Habitat Loss. Animals. 2024;14(9):1352. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ] 66. Tan SL, Zhan TT, Zeng FW, Chen XJ, Chen TZP, Li L, Wei HX, Zhang SQ, Zuo KJ. Visualization of sex identification in red-crowned crane (Grus japonensis) via recombinase-aided amplification combined with pyrococcus furiosus argonaute assay. Ecol Evol. 2025;15(7):e71780. 10.1002/ece3.71780. [ DOI ] [ PMC free article ] [ PubMed ] 67. Tesfahun T, Ejigu D. Avian communities of alatish national Park, Ethiopia. Int J Zool. 2022. 68. Thompson-Ambriz J, Moreno CE, Rangel-Salazar JL, Martínez-Morales MA. Multi-scale response of wetland bird assemblages to landscape patterns on a Neotropical island: when wetland type matters more than size. Wetlands Ecol Manage. 2020;28(2):251–69. [ Google Scholar ] 69. Tian Z, Huo D, Yi K, Que J, Lu Z, Hou J. Evaluation of suitable habitats for birds based on maxEnt and google earth engine—A case study of baer’s pochard (Aythya baeri) in Baiyangdian, China. Remote Sens. 2023;16(1):64. [ Google Scholar ] 70. Tu H-M, Fan M-W, Ko JC-J. Different Habitat Types Affect Bird Richness and Evenness. Sci Rep. 2020;10(1):1221. 10.1038/s41598-020-58202-4. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ] 71. Tubelis DP, Cavalcanti RB. Community similarity and abundance of bird species in open habitats of a central Brazilian Cerrado. Ornitologia Neotropical. 2001;12(1):57–73. [ Google Scholar ] 72. Walther BA, Chen JRJ, Lin HS, Sun YH. The Effects of Rainfall, Temperature, and Wind on a Community of Montane Birds in Shei-Pa National Park, Taiwan. ZOOLOGICAL Stud. 2017;56:Article23. 10.6620/ZS.2017.56-23. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ] 73. Wang H, Chi Y, Zhong Y, Wang Q. Habitat Suitability Dynamics of Yellow River Delta Nature Reserves for Rare Waterbirds. Sustainability. 2025;17(12):5326. [ Google Scholar ] 74. Wang RX, Yang XJ. Seasonal pattern of waterbird communities at Lake Dianchi, Yunnan– Guizhou Plateau, south-west China. Forktail. 2020;36:97–105. [ Google Scholar ] 75. Wang X, Hou X, Li Z, Wang Y. Spatial and Temporal Characteristics of Meteorological Drought in Shandong Province, China, from 1961 to 2008. Adv Meteorol. 2014;2014:873593. 10.1155/2014/873593. [ Google Scholar ] 76. Wang Y, Cheng Y-W, Dong Z-H, Zhang S-M-Y, He X-C, Zhong Y-H, Wu Y-J. Diversity and distribution of birds in Zhaojue County, Sichuan Province. 2022. 77. Wieczkowski J. Tree mortality due to an El Niño flood along the lower Tana River, Kenya. Afr J Ecol. 2009;47(1):56–62. 10.1111/j.1365-2028.2007.00918.x. [ Google Scholar ] 78. Xia C, Liu G, Xia H, Jiang F, Meng Y. Influence of saline intrusion on the wetland ecosystem revealed by isotopic and hydrochemical indicators in the Yellow River Delta, China. Ecol Ind. 2021;133:108422. 10.1016/j.ecolind.2021.108422. [ Google Scholar ] 79. Xia S, Liu Y, Chen B, Jia Y, Zhang H, Liu G, Yu X. Effect of water level fluctuations on wintering goose abundance in Poyang Lake wetlands of China. Chin Geogra Sci. 2017;27(2):248–58. [ Google Scholar ] 80. Xu D, Bisht G, Tan Z, Sinha E, Di Vittorio AV, Zhou T, Ivanov VY, Leung LR. Climate change will reduce North American inland wetland areas and disrupt their seasonal regimes. Nat Commun. 2024;15(1):2438. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ] 81. Xu XG, Chen ZX, Feng Z. From natural driving to artificial intervention: Changes of the Yellow River estuary and delta development. OCEAN Coastal Manage. 2019;174:63–70. 10.1016/j.ocecoaman.2019.03.009. [ Google Scholar ] 82. Yang X, Duan Z, Li S, Zhang C, Qu M, Hua G, Niu X, Hu H, Yu D. Factors driving the abundance of wintering waterbirds in coastal areas of Guangdong Province, China. Front Ecol Evol. 2022;9–2021. 10.3389/fevo.2021.808105. [Original Research]. 83. Yong DL, Liu Y, Low BW, Espanola CP, Choi C-Y, Kawakami K. Migratory songbirds in the East Asian-Australasian Flyway: a review from a conservation perspective. Bird Conserv Int. 2015;25(1):1–37. [ Google Scholar ] 84. Yu X, Zhang Z, Xue Z, Wu H, Zhang H. Effects of tidal channels and roads on landscape dynamic distribution in the Yellow River Delta, China. Chin Geogra Sci. 2020;30(1):170–9. [ Google Scholar ] 85. Yu X, Zhu W, Wei J, Jia S, Wang A, Huang Y, Zhao Y. Estimation of ecological water supplement for typical bird protection in the Yellow River Delta wetland. Ecol Ind. 2021;127:107783. [ Google Scholar ] 86. Zhang H, Wang F, Zhao H, Kang P, Tang L. Evolution of habitat quality and analysis of influencing factors in the Yellow River Delta Wetland from 1986 to 2020. Front Ecol Evol. 2022;10:1075914. [ Google Scholar ] 87. Zhang Q, Wu Y, Yang L, Li Z, Li Z, Yang Y, Chen S, Liu E. Tracing Aquatic Macrophyte Development in Nansi Lake, Northern China’s Largest Freshwater Lake: Plant Macrofossils From 1855 to Present. Ecol Evol. 2025;15(1):e70878. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ] 88. Zhang X, Wang G, Xue B, Zhang M, Tan Z. Dynamic landscapes and the driving forces in the Yellow River Delta wetland region in the past four decades. Sci Total Environ. 2021;787:147644. [ DOI ] [ PubMed ] [ Google Scholar ] 89. Zhi C, Cao W, Zhang Z, Li Z, Ren Y. Hydrogeochemical characteristics and processes of shallow groundwater in the Yellow River Delta, China. Water. 2021;13(4):534. [ Google Scholar ] 90. Zhou K. Wetland landscape pattern evolution and prediction in the Yellow River Delta. Appl Water Sci. 2022;12(8):190. [ Google Scholar ] 91. Zhou YY, Huang HQ, Nanson GC, Huang C, Liu GH. Progradation of the Yellow (Huanghe) River delta in response to the implementation of a basin-scale water regulation program. Geomorphology. 2015;243:65–74. 10.1016/j.geomorph.2015.04.023. [ Google Scholar ] 92. Zuo D, Cai S, Xu Z, Li F, Sun W, Yang X, Kan G, Liu P. Spatiotemporal patterns of drought at various time scales in Shandong Province of Eastern China. Theoret Appl Climatol. 2018;131(1):271–84. 10.1007/s00704-016-1969-5. [ Google Scholar ] Associated Data This section collects any data citations, data availability statements, or supplementary materials included in this article. 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