LZ说的第一个蜂鸟的阅读，好像GWD里面的一篇啊，也有蜂鸟，也有蝙蝠，麻烦帮我确认下，谢谢： Grassland songbirds oftennest in the same grassland-wetland complexes as waterfowl, particularly in acertain part of those complexes, namely, upland habitats surrounding wetlands. Althoughsome wildlife management procedures directed at waterfowl, such as habitatenhancement or restoration, may also benefit songbirds, the impact of others,especially the control of waterfowl predators, remains difficult to predict.For example, most predators of waterfowl nests prey opportunistically onsongbird nests, and removing these predators could directly increase songbirdnesting success. Alternatively, small mammals such as mice and ground squirrelsare important in the diet of many waterfowl-nest predators and can themselvesbe important predators of songbird nets. Thus. Removing waterfowl-nest predatorscould affect songbird nesting success through subsequent increases insmall-mammal populations. In 1995 and 1996, researchers trapped andremoved certain waterfowl-nest predators, primary raccoons and striped skunks,then observed subsequent survival rates for songbird nests. Surprisingly. Theyobserved no significant effect on songbird nesting success. This may be due toseveral factors. Neitherraccoons nor striped skunks consume ground squirrels, which are importantpredators of songbird nests. Thus, their removal may not have led tosignificant increases in populations of smaller predators. Additionally, bothraccoons and striped skunks prefer wetlands and spend little time in uplandhabitats; removing these species may not have increased the nesting success ofsongbirds in the uplands enough to allow detection.
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发表于 2010-2-26 21:05:19
楼主
数学太差，就不要出来误导大家，另外，答案也没有记住。