Asymmetric impact of piscivorous birds on sizestructured fish populations

被引:16
作者
Beckmann, Christa [1 ]
Biro, Peter A. [1 ]
Post, John R. [1 ]
机构
[1] Univ Calgary, Dept Biol Sci, Calgary, AB T2N 1N4, Canada
关键词
D O I
10.1139/Z06-151
中图分类号
Q95 [动物学];
学科分类号
071002 ;
摘要
Fish are frequently considered the top predator in freshwater food web models despite evidence that predatory birds can impact fish populations. In this study, we quantified bird predation rates on experimental populations of rainbow trout (Oncorhynchus mykiss (Walbaum, 1792)) created by stocking nine small lakes in British Columbia, Canada. Combining estimates of fish mortality with estimated bird predation rates allowed us to partition fish mortality into that due to birds versus cannibalism. Our results indicated that bird predators had significant impacts on age-1 trout populations, but little impact on age-0 trout. Common loons (Gavia innner Brunnich, 1764) were the principle predator among eight predatory bird species present, apparently consuming nearly 50% of all stocked age-1 trout and explaining almost 50% of variation in mortality rates. Age-1 trout mortality did not differ significantly from zero in lakes without loons. Birds consumed a small proportion of age-0 trout, and estimated consumption explained none of the variation in age-0 trout mortality among lakes. We conclude that birds affect fish populations by asymmetric predation on different age (size) classes and can be important top predators that should not be ignored when characterizing freshwater food webs in lakes.
引用
收藏
页码:1584 / 1593
页数:10
相关论文
共 45 条
[1]   ELEVATED PREDATION RISK ASSOCIATED WITH INSHORE MIGRATIONS OF FISH IN A LARGE LAKE, LOCH-LOMOND, SCOTLAND [J].
ADAMS, CE ;
BROWN, DW ;
KEAY, L .
HYDROBIOLOGIA, 1994, 290 (1-3) :135-138
[2]   SEASONAL MORTALITY OF RAINBOW-TROUT (SALMO-GAIRDNERI) PLANTED IN SMALL EUTROPHIC LAKES OF CENTRAL CANADA [J].
AYLES, GB ;
LARK, JGI ;
BARICA, J ;
KLING, H .
JOURNAL OF THE FISHERIES RESEARCH BOARD OF CANADA, 1976, 33 (04) :647-655
[3]   Aspects of Common Loon (Gavia immer) feeding biology on its breeding ground [J].
Barr, JF .
HYDROBIOLOGIA, 1996, 321 (02) :119-144
[4]   From individuals to populations: Prey fish risk-taking mediates mortality in whole-system experiments [J].
Biro, PA ;
Post, JR ;
Parkinson, EA .
ECOLOGY, 2003, 84 (09) :2419-2431
[5]  
Biro PA, 2003, ECOLOGY, V84, P691, DOI 10.1890/0012-9658(2003)084[0691:PCOAPI]2.0.CO
[6]  
2
[7]   Density-dependent mortality is mediated by foraging activity for prey fish in whole-lake experiments [J].
Biro, PA ;
Post, JR ;
Parkinson, EA .
JOURNAL OF ANIMAL ECOLOGY, 2003, 72 (04) :546-555
[8]   Predators select against high growth rates and risk-taking behaviour in domestic trout populations [J].
Biro, PA ;
Abrahams, MV ;
Post, JR ;
Parkinson, EA .
PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES, 2004, 271 (1554) :2233-2237
[9]  
Crowder LB, 1997, ECOLOGY, V78, P1796
[10]   Predation on fish by cormorants and pelicans in a cold-water river: a field and modeling study [J].
Derby, CE ;
Lovvorn, JR .
CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES, 1997, 54 (07) :1480-1493