tailieunhanh - WILDLIFE SCIENCE: LINKING ECOLOGICAL THEORY AND MANAGEMENT APPLICATIONS - CHAPTER 6

Bờ biển Texas xếp hạng là một trong những lĩnh vực ưu tiên cao nhất cho bảo tồn chim ở Bắc Mỹ bởi vì sự phong phú và đa dạng tuyệt vời của cuộc sống gia cầm. Khu vực này cung cấp giống, mùa đông, hoặc môi trường sống cho khoảng 400 loài chim di trú dừng chân (Rappole và Blacklock năm 1994; DeGraaf Rappole 1995). Hơn nữa, có khả năng nhiều hơn so với 100 triệu con chim di cư qua khu vực này mỗi mùa thu và mùa xuân. Một số loài phụ thuộc rất nhiều vào bờ biển Texas cho một. | 6 Linking Waterfowl Ecology and Management A Texas Coast Perspective Bart M. Ballard CONTENTS The Texas Coast. 96 Coastal Habitats. 96 The Rice Prairies. 98 Declines in Wetland Habitats. 98 The Northern Pintail. 99 Trends in Northern Pintail Abundance. 99 Factors Potentially Limiting Population. 100 Winter Survival. 101 Linking Optimal Migration Theory and Management. 104 References. 104 The Texas coast ranks as one of the highest priority areas for bird conservation in North America because of its great abundance and diversity of bird life. This region provides breeding wintering or migratory stopover habitat for about 400 species of birds Rappole and Blacklock 1994 DeGraaf and Rappole 1995 . Further potentially more than 100 million birds migrate through this region each fall and spring. Some species rely heavily on the Texas coast for part or all of the annual cycle. For example about 75 of all redhead ducks Aythya americana spend winter in the Laguna Madres of Texas and Tamaulipas Weller 1964 . Fish and Wildlife Service unpublished data 2004 however all these birds most likely use Texas coastal areas during migration and portions of the winter. Similarly most reddish egrets Egretta rufescens breed in Texas estuaries whereas a large proportion of western Gulf coast mottled ducks Anas fulvigula rely on coastal habitats in Texas throughout the annual cycle. Many species of neotropical migrant birds breed in temperate regions of North America and migrate to and from wintering grounds in Central and South America. A narrowing of the North American continent along with an east-west restriction of habitats suitable to many species causes large-scale convergence of migratory corridors along the Texas coast Lincoln et al. 1998 . The most direct route from breeding to wintering areas in Central and South America for species that breed in eastern portions of North America is across the Gulf of Mexico. However many species have limited flight range capabilities and are