A systematic network-based migratory bird monitoring and protection system is needed in China

Exploring the conservation of historic avian corridors under urbanization threats in China: A case study of egrets in the Greater Bay Area

This study explores the conservation of historic flyway corridors for egret in the Greater Bay Area (GBA), with a focus on habitat connectivity and dynamic corridors. To address the gaps in previous research, we used field observations, bio-climatic data and landcover information spanning three decades. Our approach involves MaxENT modeling and the Linkage Mapper method. The results showed that the MaxENT model effectively simulated the egret habitats at different levels, with coastlines and riverbanks emerging as primary habitat zones. Moreover, bio-climatic factors, particularly Bio 19 and Bio 8, played a dominant role, accounting for 90 % of the habitat suitability in 2020. Other factors contributed rather minimally. Through the utilization of resistance surface and corridor extraction methods, noteworthy alterations in the flyway networks emerged post-2000, followed by a gradual return to normal. Connectivity analyses highlighted a critical 30 km threshold for the egret preservation. Corridor widths should be determined based on cost-effective considerations. We conclude that combining MaxENT with the Linkage Mapper method, even with limited egret observations and integrating multi-source data, such as land cover, might simulate potential suitable habitats and flyway dynamics for waterbirds such as egrets. This study provides valuable insights for the egret conservation and the preservation of their habitats in the GBA, contributing to a global waterbird diversity and habitat quality.

Identification and scoring of conservation gaps in wetlands of China's coastal provinces: Implications for extending protected areas

Wetlands in China's coastal provinces are strategically positioned along migratory flyways for waterbirds, serving as essential habitats and stopover sites due to the expansive land area and abundant wetland resources they offer. This study aimed to introduce a simplified index system to enable rapid assessment and prioritization of unprotected areas for wetlands in China's coastal provinces. A spatial analysis was conducted, combining wetland distribution and existing protected areas data and spatial extent of wetlands extracted by remote sensing data. Results indicate substantial gaps in coverage, covering an area of 108.33 × 104 ha, with 76% being natural wetlands. Over half of these gaps are identified as high-value wetlands with significant ecological functions. The uneven distribution of unprotected wetlands reflects a tension between economic development and wetland conservation. Our findings support the expansion of the existing coastal wetland protected areas' coverage, as well as protecting critical habitats in conservation gaps, and establishing of a network-based waterbird protection system. This research contributes to informed decision-making and policy in wetlands' conservation planning.

Assessment of the correlation between the nutrient load from migratory bird excrement and water quality by principal component analysis in a freshwater habitat

Waterbirds depend on a dispersed network of wetlands for their annual life cycle during migration. Climate and land use changes raise new concerns about the sustainability of these habitat networks, as water scarcity triggers ecological and socioeconomic impacts threatening wetland availability and quality. During the migration period, birds can be present in large enough numbers to influence water quality themselves linking them and water management in efforts to conserve habitats for endangered populations. Despite this, the guidelines within laws do not properly account for the annual change of water quality due to natural factors such as the migration periods of birds. Principal component analysis and principal component regression was used to analyze the correlations between the presence of a multitude of migratory waterbird communities and water quality metrics based on a dataset collected over four years in the Dumbrăvița section of the Homoród stream in Transylvania. The results reveal a correlation between the presence and numbers of various bird species and the seasonal changes in water quality. Piscivorous birds tended to increase the phosphorus load, herbivorous waterbirds the nitrogen load, while benthivorous duck species influenced a variety of parameters. The established PCR water quality prediction model showed accurate prediction capabilities for the water quality index of the observed region. For the tested data set, the method provided an R² value of 0.81 and a mean squared prediction error of 0.17.

Habitat loss exacerbates pathogen spread: An Agent-based model of avian influenza infection in migratory waterfowl

Habitat availability determines the distribution of migratory waterfowl along their flyway, which further influences the transmission and spatial spread of avian influenza viruses (AIVs). The extensive habitat loss in the East Asian-Australasian Flyway (EAAF) may have potentially altered the virus spread and transmission, but those consequences are rarely studied. We constructed 6 fall migration networks that differed in their level of habitat loss, wherein an increase in habitat loss resulted in smaller networks with fewer sites and links. We integrated an agent-based model and a susceptible-infected-recovered model to simulate waterfowl migration and AIV transmission. We found that extensive habitat loss in the EAAF can 1) relocate the outbreaks northwards, responding to the distribution changes of wintering waterfowl geese, 2) increase the outbreak risk in remaining sites due to larger goose congregations, and 3) facilitate AIV transmission in the migratory population. In addition, our modeling output was in line with the predictions from the concept of "migratory escape", i.e., the migration allows the geese to "escape" from the location where infection risk is high, affecting the pattern of infection prevalence in the waterfowl population. Our modeling shed light on the potential consequences of habitat loss in spreading and transmitting AIV at the flyway scale and suggested the driving mechanisms behind these effects, indicating the importance of conservation in changing spatial and temporal patterns of AIV outbreaks.

Is Ecological Birdwatching Tourism a More Effective Way to Transform the Value of Ecosystem Services?-A Case Study of Birdwatching Destinations in Mingxi County, China

Ecological birdwatching tourism is an ecological product and an essential part of ecotourism, and the realization of its recreation value is crucial for improving human well-being, and realization of the local benefits of ecosystem services for areas focused on biodiversity conservation, especially in bird species. In this study, we use travel cost interval analysis, one of the travel cost derived models featuring more easily satisfied assumptions and less limited data, to evaluate the recreation value of the ecological bird-watching tourism destination, and compare it with the general ecotourism, of Mingxi County destination in China. The results show that, firstly, the per capita recreation value of eco-birdwatching is 3.9 times that of general eco-tourism, its per capita social benefit is three times that of general eco-tourism, and its per capita economic benefit is 4.5 times that of general eco-tourism. Secondly, compared with general ecotourists, the per capita travel costs of eco-birdwatchers are higher, and there were significant statistical differences in the expenses for catering, tickets, shopping, opportunity cost, and total travel expenses between these two groups. Thirdly, in comparison with general ecotourists, the marginal cost of an individual eco-birdwatcher is higher, and the travel intention of an eco-birdwatcher is more robust at the same cost level. The price of a single eco-birdwatcher is higher under the same travel intention demand level. In short, the ecological bird-watching industry has a higher marginal value than general eco-tourism and has higher social, economic, and ecological benefits, bringing a higher level of development for the local tourism industry.