Internationally Important Waterbird Sites in Manila Bay, Philippines
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Internationally Important Waterbird Sites in Manila Bay, Philippines Arne E. Jensen October 2018 Pages from this publication may be reproduced freely for educational, conservation and other non-commercial purposes. Prior permission must be given for all other forms of reproduction. Full credit must always be given to the copyright holders. Technical Report: Internationally Important Waterbird Sites in Manila Bay, Philippines. Arne E. Jensen. Version October 2018. Citation: Jensen, A.E. (2018). Internationally Important Waterbird Sites in Manila Bay, Philippines, October 2018. Technical Report. Wetlands International and IUCN National Committee of the Netherlands. Cover photograph: Congregations of Black-headed Gull Chroicocephalus ridibundus at the Sasmuan Bangkung Malapad wetland in Pasac River, Pampanga province by Christian Perez. The statements and the conclusions found in the report are those of the author, and may not necessarily be the view of Wetlands International and IUCN NL. CONTENTS Contents i Acronyms iv Summary v Background……………………………………………………………………………………………………………… 1 Introduction……………………………………………………………………………………………………………… 2 Methods…………………………………………………………………………………………………………………… 2 Limitations……………………………………………………………………………………………………………… 3 Results……………………………………………………………………………………………………………………… 5 5.1 Waterbirds………………………………………………………………………………………………… 5 5.1.1 Waterbirds in Manila Bay……………………………………………………………………. 5 5.1.2 Distribution of waterbirds…………………………………………………………………… 7 5.1.3 Population size…………………………………………………………………………………… 10 5.1.4 Waterbird species and populations of international conservation importance………………………………………………………………………………………… 13 5.1.5 Globally Threatened and Near Threatened waterbirds……………………… 18 5.1.6 Waterbird population trends……………………………………………………………… 22 5.2 Habitats……………………………………………………………………………………………………… 30 5.2.1 Foreshore areas ………………………………………………………………………………… 30 5.2.2 Mudflats and sandbars……………………………………………………………………… 33 5.2.3 Mangroves………………………………………………………………………………………… 37 5.2.4 Fishponds (former mangroves, nipa swamps and foreshore areas)…… 43 5.2.5. Brackish tidal swamps………………………………………………………………………… 45 5.2.6 Saltmarshes………………………………………………………………………………………… 46 Chapter 6 Conclusions……………………………………………………………………………………………… 47 Chapter 7 Acknowledgements………………………………………………………………………………… 51 Chapter 8 References……………………………………………………………………………………………… 52 List of Tables Table 1. Globally Threatened and Near Threatened species……………………………………… 6 Table 2. Number of resident and migratory waterbird species…………………….…………… 7 Table 3. Main habitat preferences by migratory waterbirds……………………………………… 8 Table 4. Minimum number of waterbirds based on peak count data compared to 11 average count values 2014 to 2018……………………………………………………………… Table 5. Ramsar Convention criteria relevant for waterbirds and their habitats……… 13 Table 6. Sites in Manila Bay of international importance for congregation of migratory waterbirds and for threatened waterbird species………………………… 14 Table 7. Waterbird species of international flyway importance…………………….………… 15 Table 8. Population trends of waterbirds in AWC and WBCP monitored sites…………… 24 i Table 9. Population trends for species occurring in international important numbers……………………………………………………………………………………………………… 25 Table 10. Trends of 18 internationally important waterbird populations in annually monitored wetland sites……………………………………………………………… 26 Table 11. Population trends of Heron and Egret species in AWC and WBCP monitored sites……………………………………………………………………………………………. 27 Table 12. Trends of shorebird species in AWC and WBCP monitored sites………………… 28 Table 13. Trends of Gull and Tern species in AWC and WBCP monitored sites……………. 29 Table 14. Estimated changes in Manila Bay wetlands within 2 meter water depth……………………………………………………………………………………………….… 30 Table 15. Mudflat areas per province in Manila Bay……………………………………………..………… 36 List of Figures Figure 1. Distribution of waterbirds in numbers of international importance……………… 9 Figure 2. Distribution of main wetlands habitats in Manila Bay………………………………… 31 Figure 3. Fish biomass distribution in 2015, waterbird congregation areas and proposed reclamation areas in northern Manila Bay…………………………………… 32 Figure 4. Distribution of coastal mangroves in Manila Bay……….………………………………… 38 Figure 5. Trend in mangrove extent along the coastline of Manila Bay from 1977 to 2015……………………………………………………………………………………………… 39 Figure 6. Development of fishponds in the Pampanga Delta and Hagonoy, Bulacan from 1976 to 2013……………………………………………………………………………………… 44 List of Plates Plate 1. Flock of Kentish Plover and Red-necked Stint at lowtide in coastal Bulacan… 6 Plate 2. Feeding congregation of Great Egret, Intermediate Egret and Little Egret in a drained fishpond in Bulakan municipality……………………………………………… 10 Plate 3. Congregations of Black-winged Stilt at coastal fishponds at Balanga City………………………………………………………………………………………………… 12 Plate 4. Murmurations of shorebirds in Bulacan………………………………………………………. 12 Plate 5. Black-winged Stilts and Whiskered Terns feeding in a drained fishpond in Obando, Bulacan……………………………………………………………………………………… 12 Plate 6. Thousands of Great Egrets and Little Egrets overwinter in Bataan and in the Pampanga Delta………………………………………………………………………………… 16 Plate 7. Congregations of more than 29,000 Black-headed Gulls are found in the coastal Pampanga ………………………………………………………………………………… 17 Plate 8. More than 19% of the EAAF population of Pacific Golden Plover overwinter in Bulacan…………………………………………………………………………………… 19 Plate 9. Caspian Tern has in Manila Bay its second Philippine overwintering site………………………………………………………………………………………………………….…… 20 ii Plate 10. The globally threatened Chinese Egret occur in Manila Bay wetlands……………………………………………………………………………………………………….. 2 2 Plate 11. Dredging of shallow foreshore areas and of rivers is a widespread activity in Manila Bay…………………………………………………………………………………… 33 Plate 12. Foreshore area under conversion into fishponds in Bataan and Pampanga province……………………………………………………………………………………………………… 34 Plate 13. Mudflat sample from Barangay Talitip, Bulacan showing the richness of macrobenthic organisms……………………………………………………………………………… 35 Plate 14. Mudflat habitats found in the Province of Bulacan……………………………………… 36 Plate 15. Patches of old growth natural mangroves in Bulacan province……………………… 40 Plate 16. Most of the foreshore, intertidal mudflats in Manila Bay are converted to mangrove plantations……………………………………………………………………………… 41 Plate 17. Conversion of mudflats of Sasmuan Bangkung Malapad Critical Habitat and Ecotourism Area has reduced migratory shorebirds’ feeding 42 area……………………………………………………………………………………………………………… Plate 18. Pond dikes disconnecting the tidal inundation of natural mangroves as part of fishpond conversion in the Pampanga Delta…………………………………… 45 Plate 19. Nipa plantations located in the central Pampanga Delta……………………………… 46 Annexes Annex 1. Coastal localities in Manila Bay searched for waterbirds from 2016 to 2018… 56 Annex 2. Taxonomic list of waterbirds recorded in Manila Bay from 2003 to 2018……… 57 Annex 3. Waterbird species in Manila Bay listed under the Convention on Migratory Species………………………………………………………………………………………………………… 59 Annex 4. Localities in Manila Bay with waterbird concentrations, the peak numbers and the average number of waterbirds………………………………………………………… 61 Annex 5. Map of Key Areas for Waterbirds of International Importance……………………… 64 Annex 6. Migratory threatened and Near Threatened species in Manila Bay wetland sites and numbers of individuals recorded from 2003 to 2018……………………… 66 Annex 7. Trends of waterbirds in the five Manila Bay sites monitored annually since 2003 (2009)…………………………………………………………………………………………………… 69 Annex 8. Development and conversions of natural wetland habitats in the Pampanga Delta and Hagonoy, Bulacan.…………………………………………………………………………. 71 iii ACRONYMS AFP Armed Forces of the Philippines AWC Asian Waterfowl Census BFAR Bureau of Fisheries and Aquatic Resources BMB Biodiversity Management Bureau DA Department of Agriculture DENR Department of Environment and Natural Resources DPWH Department of Public Works and Highways EAAF East Asia- Australasia Flyway ESSC Environment Science for Social Change IBA Important Bird and Biodiversity Area (an area identified as being globally important for the conservation of bird populations) IUCN NL International Union for Conservation of Nature – National Committee of the Netherlands KBA Key Biodiversity Area (a site contributing significantly to the global persistence of biodiversity) LPPCHEA Las Piñas - Parañaque Critical Habitat and Ecotourism Area NAMRIA National mapping and Resource Information Authority NEDA National Economic Development Authority NCR National Capital Region NGO Non-Government Organization PRA Philippine Reclamation Authority TEEB The Economics of Ecosystems and Biodiversity UNEP United Nations Environment Program WBCP Wild Bird Club of the Philippines iv SUMMARY Information about the presence and status of migratory waterbirds and their habitats in Manila Bay, Philippines are lacking. This study presents the results of the species, numbers and distribution of migratory waterbirds as well as the status of their wetland habitats of international importance for conservation. Intertidal wetlands, such as those located in Manila Bay provide many ecosystem services but they are not well known in the Philippines. These ecosystems and migratory waterbirds, among other lifeforms, are increasingly under threat from socio-economic activities that result to their poor status. In Manila