Key conservation issues for migratory land- and waterbird species on the world's major flyways

Abstract

SummaryAn estimated 19% of the world's 9,856 extant bird species are migratory, including some 1,600 species of land-and waterbirds. In 2008, 11% of migratory land-and waterbirds were classed by BirdLife International as threatened or near-threatened on the IUCN Red List. Red List indices show that these migrants have become more threatened since 1988, with 33 species deteriorating and just six improving in status. There is also increasing evidence of regional declines. Population trend data show that more Nearctic-Neotropical migrants have declined than increased in North America since the 1980s, and more Palearctic-Afrotropical migrants breeding in Europe declined than increased during 1970-2000. Reviews of the status of migratory raptors show unfavourable conservation status for 51% of species in the African-Eurasian region (in 2005), and 33% of species in Central, South and East Asia (in 2007). Land-use change owing to agriculture is the most frequently cited threat affecting nearly 80% of all threatened and nearthreatened species. However, while agricultural intensification on the breeding grounds is often proposed as the major driver of declines in Palearctic-Afrotropical migrants, some species appear to be limited by the quantity and quality of available habitat in non-breeding areas, notably the drylands of tropical Africa. Forest fragmentation in breeding areas has contributed to the declines of Nearctic-Neotropical migrants with deforestation in non-breeding areas another possible factor. Infrastructure development including wind turbines, cables, towers and masts can also be a threat. Over-harvesting and persecution remain serious threats, particularly at key migration locations. Climate change is affecting birds already, is expected to exacerbate all these pressures, and may also increase competition between migratory and non-migratory species. The conservation of migratory birds thus requires a multitude of approaches. Many migratory birds require effective management of their critical sites, and Important Bird Areas (IBAs) provide an important foundation for such action; however to function effectively in conserving migratory species, IBAs need to be protected and the coherence of the network requires regular review. Since many migratory species (c. 55%) are widely dispersed across their breeding or nonbreeding ranges, it is essential to address the human-induced changes at the wider landscape scale, a very considerable challenge. Efforts to conserve migratory birds in one part of the range are less effective if unaddressed threats are reducing these species' populations and habitats elsewhere. International collaboration and coordinated action along migration flyways as a whole are thus key elements in any strategy for the conservation of migratory birds.

Quantifying drivers of population dynamics for a migratory bird throughout the annual cycle

“…Quantifying the causes of population fluctuations is particularly challenging for migratory species because the breeding abundance of these species can be influenced by events experienced across the annual cycle [3,4]. Worldwide, migratory species, including over half of migratory bird species [5], are undergoing rapid, enigmatic declines, and implementing effective conservation measures is hindered by both the lack of information about limiting factors and the political, social and economic complexities of international conservation [6].…”

Convergence of broad-scale migration strategies in terrestrial birds

“…The migration of birds is a well-studied example, with ca 19% of extant bird species identified as migratory [2]. The hazards associated with migration can have negative effects on the survival and reproductive success of bird populations [3,4].…”

Landscape-Level Associations of Wintering Waterbird Diversity and Abundance from Remotely Sensed Wetland Characteristics of Poyang Lake

“…More than 400 waterbird species, including long-distance migrants, critically depend on wintering habitat in wetlands of warm low-latitude regions, large extents of which have been lost to agriculture, residential sprawl and modifications to store or manage water resources in recent decades [1][2][3][4][5][6][7][8]. The United Nations has designated a number of conservation targets and wetlands of international importance under the Ramsar Convention [9].…”