Summary of Knowledge on the Status of Waders And
Total Page：16
File Type：pdf, Size：1020Kb
SUMMARY OF KNOWLEDGE ON THE STATUS OF WADERS AND COASTAL SEABIRDS ON KEY NATURAL SITES OF THE WEST AFRICA’S COASTLINE Knowledge synthesis written by Pierre Campredon Within the framework of the MAVA Action Plan for the conservation of wetlands and coastal birds in West Africa Thanks to the following contributors: Amadou Diam Ba Paul Ndiaye Mohamed Henriques ©2019 TABLE OF CONTENTS 3 TABLE OF CONTENTS ABSTRACT ............................................................................................................................ 4 INTRODUCTION .................................................................................................................... 6 INFORMATION AND DATA SOURCES ................................................................................... 8 CENSUS MODALITIES AND SCOPE ....................................................................................10 RELEVANT BIRD POPULATIONS .........................................................................................12 Waders ..............................................................................................................................................12 Coastal seabirds ..............................................................................................................................16 STATUS OF COASTAL WATERBIRDS ON KEY SITES ..........................................................18 Banc d’Arguin National Park ........................................................................................................18 Senegal River lower delta .............................................................................................................. 22 Saloum Delta National Park (PNDS) ............................................................................................ 25 The Bijagós Archipelago ................................................................................................................ 28 CONCLUSION ...................................................................................................................... 34 BIBLIOGRAPHY ................................................................................................................... 38 The status of waders and coastal seabirds on key natural sites of the West Africa’s coastline ABSTRACT A review of the status of coastal waterbirds º 6 to 8 months per year, West Africa’s on key sites of the West Africa’s coastline sites are home to a significant number was undertaken as part of the Plan of of small or migratory waders that breed action for the conservation of wetlands and from Northern Europe to the Canadian coastal birds (PAZHOC). The conclusions Arctic through Siberia, and belong to below were arrived at after examining, the East-Atlantic Flyway. in the light of international bird counts º Populations of these waders have been and scientific publications, the reports globally declining since 1980s-1990s. on priority sites, i.e. the Banc d’Arguin National Park (PNBA) and the Diawling º The causes of this decline are difficult National Park in Mauritania, the Langue to establish or prioritise, owing to the de Barbarie National Park and the Saloum fact these populations live in different Delta National Park (PNSD) in Senegal, and environments throughout the year. the Bijagós Archipelago Biosphere Reserve The two African sites hosting the big in Guinea-Bissau: majority of their individuals, i.e. the Banc The status of waders and coastal seabirds on key natural sites of the West Africa’s coastline ABSTRACT 5 d’Arguin and the Bijagós Archipelago, The overall status of coastal seabird species do not seem to have undergone covered by the Plan of action looks good, at changes that alone could explain such least for Caspian and Royal Terns as well as a decline. Although a few changes did Slender-billed Gulls whose populations are occur, including the evolving pressure considered to be either stable or growing. exerted by fisheries, it should be noted, Although improvements have been made however, that water birds feeding on to count techniques, especially through the fishes have been less affected than introduction of drones, these results need those feeding on invertebrates living in to be considered with precaution, owing the mud. to the threats facing colonial birds in the more or less long term. Indeed, on all sites, º The causes of the decline may lie observers have noted the erosion of sandy in the migratory process, when islets, which provide a nesting habitat weather conditions are not conducive, for those species, and frequent episodes compelling birds to change their of clutch submersion, which has to be itineraries and stopover sites. They may correlated with sea level rise. Other threats also be found on the stopover sites include nest predation, the disturbance which play a key role by enabling birds caused by tourism or the introduction to replenish their body reserves before of free-ranging pigs on the island where heading to their breeding grounds, often major colonies of terns are likely to find a located at more than 10,000 km from home in the Bijagós Archipelago. their wintering sites in Africa. It is a known fact that the Wadden Sea in the Waterbirds must not only be considered Netherlands is the key stopover site of for their intrinsic value as components these species, and that it has suffered of biodiversity. Their functions in the degradation due to mudflats being maintenance and balance of coastal mechanically dredged for the industrial ecosystems must also be recognised. exploitation of shells or sand extraction. Consideration must also be given to their role as indicators of changing º Finally, the causes may be linked environments. This is particularly true of to the very breeding grounds in waders which fly over large parts of the situations where weather conditions globe during their annual cycle through are unfavourable or when, for want of a variety of biomes and climate zones, lemmings (rodents) in great numbers, and can therefore serve as “integrative foxes or raptors hunt waders for food. sentinels” for the global changes that are º It is a fact that in the longer term, currently affecting our planet. climate changes will play a role in the In the face of the uncertainties about the evolution of wader species. On African future of coastal birds, there is a need sites, the rise in temperature could lead to step up efforts in terms of scientific to hyperthermia phenomena in birds research, technicians’ training and when during the moult. As for the rise institutional strengthening at the national in the sea level, it will impact the spatial level within the framework of partnerships and temporal accessibility of mudflats to be established on the scale of the flyway as a source of feeding for birds. as a whole, as is currently the case under the PAZHOC Plan. The status of waders and coastal seabirds on key natural sites of the West Africa’s coastline INTRODUCTION shorebirds, which are among the greatest The interface between sea and migratory birds in the world and have no land is where the world’s most other place to live. productive habitats are found The conservation of shorebirds and coastal seabirds as well as their habitats is of The interface between sea and land is particular importance, not only because where the world’s most productive habitats they represent a resource shared by several are found: shallow seas, intertidal mudflats, countries from the tropical latitudes to mangroves and coastal swamps. This is the Arctic Circle, but also because they where the bulk of human populations live, play an ecological role in the coastal where global industries are concentrated ecosystems that provide essential services and where food is produced on fertile soils. to human populations. For these reasons, This is also where the impact of sea level their conservation has been established rise and the fast-changing river flows is as a priority by national bodies dealing most felt. Present as well in this zone are with biodiversity and protected areas, in The status of waders and coastal seabirds on key natural sites of the West Africa’s coastline INTRODUCTION 7 partnership with regional and international count methods. Since it remains to be organisations involved in joint initiatives for established whether this is a structural the protection of their biodiversity under evolution or a temporal fluctuation, the PRCM and AEWA/CMS, among others. there is an urgent need for research and monitoring work to be done on the basis of concerted programmes, such as the Plan of Globally the size of the action on wetlands and coastal birds being implemented in West Africa by a range of populations of waterbirds national and international partners. concerned decreased by It was in this context that it was deemed appropriate to produce a document nearly 2.5 million individuals providing an overview of the status of between 2003 and 2014 the populations of waders and coastal seabirds on each of the key sites covered by the PAZHOC Plan. Summary papers In 2015, Wetlands International published were thus prepared for the Banc d’Arguin an alarming report on the status of National Park (Ba et al. 2018), the lower waterbirds of the East Atlantic Flyway. Delta of the Senegal River, including the The report reviewed the status of 66 bird Diawling National Park (Ba et al. 2018) and populations against data from international the Langue de Barbarie National Park (Diop counts covering several years (Wetlands et al.