Seasonal pattern of breeding, population trend and conservation status of bank cormorants Phalacrocorax neglectus off south western Africa

被引:29
作者
Crawford, RJM
Dyer, BM
Cordes, I
Williams, AJ
机构
[1] Sea Fisheries Res Inst, ZA-8012 Cape Town, South Africa
[2] Minist Fisheries & Marine Resources, Luderitz, Namibia
[3] Cape Nat Conservat, ZA-7600 Stellenbosch, South Africa
关键词
bank cormorant; breeding season; conservation status; Namibia; population; South Africa;
D O I
10.1016/S0006-3207(98)00042-1
中图分类号
X176 [生物多样性保护];
学科分类号
090705 ;
摘要
At Robben and Malgas islands off western South Africa, the main breeding season for bank cormorants Phalacrocorax neglectus normally extends from May to October. At Ichaboe and Mercury islands, off central Namibia, most breeding activity is usually concentrated between November and April. The overall number of breeding pairs of bank cormorants fell from 8672 in 1978-80 to 4888 in 1995-1997. Human disturbance resulted in the loss of four colonies and reduced populations at six others. About 3000 pairs were lost from the Mercury and Ichaboe islands because of displacement of birds from Mercury Island by Cape fur seals Arctocephalus pusillus in the 1980s and a severe reduction in food off central Namibia in the 1990s. Competition with seals for space occurs at several other localities. Using IUCN criteria, the bank cormorant merits classification as 'vulnerable'. (C) 1998 Elsevier Science Ltd. All rights reserved.
引用
收藏
页码:49 / 58
页数:10
相关论文
共 33 条
[1]  
[Anonymous], [No title captured]
[2]  
BROOKE RK, 1984, 97213 S AFR NAT SCI
[3]  
Collar N.J., 1985, THREATENED BIRDS AFR
[4]  
Cooper J., 1988, Cormorant, V16, P55
[5]   BIOLOGY OF THE BANK CORMORANT .1. DISTRIBUTION, POPULATION-SIZE, MOVEMENTS AND CONSERVATION [J].
COOPER, J .
OSTRICH, 1981, 52 (04) :208-215
[6]   BIOLOGY OF THE BANK CORMORANT .2. MORPHOMETRICS, PLUMAGE, BARE PARTS AND MOLT [J].
COOPER, J .
OSTRICH, 1985, 56 (1-3) :79-85
[7]  
Cooper J., 1982, Cormorant, V10, P57
[8]   COMPETITION FOR SPACE - RECOLONIZING SEALS DISPLACE ENDANGERED, ENDEMIC SEABIRDS OFF NAMIBIA [J].
CRAWFORD, RJM ;
DAVID, JHM ;
WILLIAMS, AJ ;
DYER, BM .
BIOLOGICAL CONSERVATION, 1989, 48 (01) :59-72
[9]  
CRAWFORD RJM, 1995, S AFR J MARINE SCI, V15, P269
[10]  
CRAWFORD RJM, 1987, OCEANOGR MAR BIOL, V25, P353