The Paradox of Shorebird Diversity and Abundance in the West Coast and East Coast of India: A Comparative Analysis

Migratory shorebirds that move across continents along their flyways are undergoing a drastic decline globally. A greater proportion of them that regularly winter along the Indian coasts within the Central Asian Flyway (CAF) are also undergoing severe declines. However, the mechanisms underlying the population trends in these areas remain little understood. This study investigated the diversity, abundance, population dynamics and distribution patterns of shorebirds along the Indian coasts based on the available literature. The west coast of India is relatively less studied than the east coast in the CAF. Further, we observed that the diversity, abundance, population dynamics and distribution pattern of the shorebirds follow different trends on the west coast compared to the east coast. These variations are in accordance with the differences in topography and biotic and abiotic factors between the coasts. Anthropogenic activities have far-reaching effects on the survival and persistence of shorebirds along the coasts. The west coast is evidently more productive than the east coast at every trophic level and thus the west coast is expected to account for more abundance and diversity of shorebirds. Paradoxically, we found that the east coast supports a greater abundance and diversity of shorebirds than the west coast. The west coast, therefore, requires further investigations to obtain a better understanding of the causes of apparent differences in abundance and diversity as well as the observed declines in shorebirds, compared to the east coast of India

Traditional fishing activities enhance the abundance of selected waterbird species in a wetland in India

Abstract Background Waterbirds are globally declining as a result of habitat loss, alteration or degradation. Fishing activities may affect waterbird distribution, abundance and diversity, and traditional fishing activities often enhance waterbird abundance. We tested this hypothesis by studying the abundance and diversity of selected common waterbird species in the Kadalundi–Vallikkunnu Community Reserve, a globally significant wetland in southwestern India in relation to fishing activities. Methods We monitored waterbird abundance four times a month from 2012 to 2015 using direct observation method during low tide. Traditional bamboo fish traps were deployed during the first and third weeks of each month. ANOVAs (one-way and multi-way) were used to examine how waterbird counts diversity varied in relation to years, seasons and period of fishing traps. Additionally we conducted a linear regression to examine the relationship between fish occurrence and waterbird counts and diversity. Results Waterbird counts varied with years and seasons, with the maximum counts being recorded during the post-monsoon (winter). Individual species varied in their responses to trap deployment. Small waterbird species usually forage in shallow shorelines, increased during trap deployment whereas the larger waterbirds were not affected by trap deployment because they tend to hunt in deeper waters. The total fish captured was an important predictor of both waterbird abundance and diversity. Conclusion In this study we documented a positive association between traditional fish trap deployment and waterbird counts and diversity. Providing high quality habitats for waterbirds as well as effective sustainable livelihoods through traditional fisheries is a critical management issue

Activation of innate immunity by 14-3-3 ε, a new potential alarmin in osteoarthritis

International audienceObjective: The innate immune system plays a central role in osteoarthritis (OA). We identified 14-3-3ε as a novel mediator that guides chondrocytes toward an inflammatory phenotype. 14-3-3ε shares common characteristics with alarmins. These endogenous molecules, released into extracellular media, are increasingly incriminated in sustaining OA inflammation. Alarmins bind mainly to toll-like receptor 2 (TLR2) and TLR4 receptors and polarize macrophages in the synovium. We investigated the effects of 14-3-3ε in joint cells and tissues and its interactions with TLRs to define it as a new alarmin involved in OA.Design: Chondrocyte, synoviocyte and macrophage cultures from murine or OA human samples were treated with 14-3-3ε. To inhibit TLR2/4 in chondrocytes, blocking antibodies were used. Moreover, chondrocytes and bone marrow macrophage (BMM) cultures from knockout (KO) TLRs mice were stimulated with 14-3-3ε. Gene expression and release of inflammatory mediators [interleukin 6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor alpha (TNFα)] were evaluated via reverse transcription quantitative polymerase chain reaction (RT-qPCR) and ELISA.Results: In vitro, 14-3-3ε induced gene expression and release of IL6 and MCP1 in the treated cells. The inflammatory effects of 14-3-3ε were significantly reduced following TLRs inhibition or in TLRs KO chondrocytes and BMM.Conclusions: 14-3-3ε is able to induce an inflammatory phenotype in synoviocytes, macrophages and chondrocytes in addition to polarizing macrophages. These effects seem to involve TLR2 or TLR4 to trigger innate immunity. Our results designate 14-3-3ε as a novel alarmin in OA and as a new target either for therapeutic and/or prognostic purposes

Long-term anthropogenic stressors cause declines in kingfisher assemblages in wetlands in southwestern India

Fragile wetland habitats are susceptible to multiple threats from anthropogenic activities. Direct waste deposition, habitat modification and overexploitation of fish have caused alternations in food webs in wetlands. Kingfishers are ecological indicators with the potential ability to respond to the minute changes in their microenvironment. Their abundance and distribution at wetland habitats are affected by multiple environmental factors. We studied the kingfisher assemblages in India to determine proximate and ultimate causes of their decline. We recorded the abundance of five species of kingfishers across five wetland habitats from 2011 to 2020 in Kerala, southwest coast of India. Kingfishers were counted twice in a month between 6.00 and 12.00 hrs. Air temperature, water temperature, humidity and turbidity were recorded. We measured fish diversity and abundance and organic waste as an additional explanatory variable. One-way ANOVA, Autoregressive Integrated Moving Average model and structural equation modelling were used to determine which explanatory variables affected kingfisher populations. Air temperature, water temperature and turbidity increased significantly during the study and had negative effects on the abundance of kingfishers. Humidity decreased significantly but had no effect on the kingfisher abundance. Fish abundance declined and had a strong positive effect on the abundance of kingfishers. The analysis of incidence of wastes across the study areas revealed that, all the sites were severely polluted. We also observed drastic decline in the abundance of all the species of kingfishers studied across the sites with a rapid decline in Pied Kingfisher and slower decline in White-throated Kingfisher. Black-capped Kingfisher is a local migrant to the study areas and is already red listed and categorized as Vulnerable (VU). This study suggests that kingfisher assemblages are declining along with the health status of the habitat. Urgent action is needed to help in designing and implementing effective management strategies for the sustainability of wetlands in the region.Peer reviewe

The Paradox of Shorebird Diversity and Abundance in the West Coast and East Coast of India: A Comparative Analysis

Migratory shorebirds that move across continents along their flyways are undergoing a drastic decline globally. A greater proportion of them that regularly winter along the Indian coasts within the Central Asian Flyway (CAF) are also undergoing severe declines. However, the mechanisms underlying the population trends in these areas remain little understood. This study investigated the diversity, abundance, population dynamics and distribution patterns of shorebirds along the Indian coasts based on the available literature. The west coast of India is relatively less studied than the east coast in the CAF. Further, we observed that the diversity, abundance, population dynamics and distribution pattern of the shorebirds follow different trends on the west coast compared to the east coast. These variations are in accordance with the differences in topography and biotic and abiotic factors between the coasts. Anthropogenic activities have far-reaching effects on the survival and persistence of shorebirds along the coasts. The west coast is evidently more productive than the east coast at every trophic level and thus the west coast is expected to account for more abundance and diversity of shorebirds. Paradoxically, we found that the east coast supports a greater abundance and diversity of shorebirds than the west coast. The west coast, therefore, requires further investigations to obtain a better understanding of the causes of apparent differences in abundance and diversity as well as the observed declines in shorebirds, compared to the east coast of India

Long-Term Population Trends and Diversity Shifts among Shorebirds: A Predictor of Biodiversity Loss along the Arabian Gulf Coasts

Bahrain is a cluster of islands in the mid-section of the Arabian Gulf that serves as an important wintering and stop-over ground for many migratory shorebirds in the Central Asian Flyway (CAF). However, natural and anthropogenic factors have had a significant impact on these ecosystems over the last few decades. Long-term, systematic studies based on standardized survey observations are needed to understand the population dynamics and diversity changes of shorebirds in these critical sites. We systematically surveyed the shorebird population and community in Bahrain between 2010 January to 2021 December. This is the first comprehensive study from the entire Kingdom of Bahrain, and covered 13 sites over 12 years to establish the results. A total of 39 species were encountered during the study period from all 13 sites in Bahrain, of which 27 species were common and regular migrants to all the study sites; these were selected to analyze the population trend. Five species represented 77% or more of the total wintering shorebird population. All the shorebird species assessed exhibited significant declining trends over the years, and majority of them had over 1% relative abundance. Shorebirds in Bahrain were severely threatened at these sites, indicating that their population trend in the area could be crucially affected. Further conservation efforts are needed, aided by an understanding of the mechanisms driving the decline and diversity changes of shorebirds in the most stressed coastal regions of Bahrain. Further studies organized throughout the country’s coasts may aid in establishing improved conservation measures to protect the shorebirds of the CAF in Bahrain