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Grassland songbirds often nest in the same grassland-wetland [#permalink]
17 Oct 2007, 09:58
Grassland songbirds often nest in the same grassland-wetland complexes
as waterfowl, particularly in a certain Line part of those complexes, namely, upland habitats surrounding wetlands. Although some wildlife management procedures directed at waterfowl, such as habitat enhancement 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 on songbird nests, and removing these predators could directly increase songbird nesting success. Alternatively, small mammals such as mice and ground squirrels are important in the diet of many waterfowl-nest predators and can themselves be important predators of songbird nest. Thus, removing waterfowl-nest predators could affect songbird nesting success through subsequent increases in small-mammal populations.
In 1995 and 1996, researchers trapped and removed certain waterfowlnest predators. primary raccoons and striped skunks, then observed subse- quent survival rates for songbird nests. Surprisingly. They observed no significant effect on songbird nesting success. This may be due to several factors. Neither raccoons nor striped skunks consume ground squirrels, which are important predators of songbird nests. Thus, their removal may not have led to significant increases in populations of smaller predators. Additionally, both raccoons and striped skunks prefer wetlands and spend little time in upland habitats; removing these species may not have increased the nesting success of songbirds in the uplands enough to allow detection.
Q1-According to the passage, which of the following is true about the role played by ground squirrels in the ecology of grassland-wetland complexes?
A. While not important in the diet of raccoons or striped skunks, ground
squirrels are a significant source of food for other waterfowl-nest predators.
B. Whereas ground squirrels are typically important as predators of
songbird nests, their opportunistic predation on waterfowl nests also has an observable effect on waterfowl nesting success.
C. Although most waterfowl-nest predators prey on small mammals such as mice and ground squirrels, populations of ground squirrels tend to increase quickly enough to compensate for this level of predation.
D. Although ground squirrels have been known to prey on songbird nests, a larger portion of their diets is usually provided by predation on waterfowl nests.
E. Since larger predators tend to prefer small mammals to songbird eggs as a food source, a large population of ground squirrels plays an important role in controlling opportunistic predation on songbird nests.
Q2-Which of the following best describes the function of the sentence “Neither
raccoons…songbird nests” (lines 34-37 - underlined ) in the context of the passage as a whole?
A. It raises questions about the validity of a theory described in the first paragraph.
B. It points out an oversimplification that is inherent in the argument presented in the first paragraph.
C. It introduces information that may help explain the results of the experiment that are presented earlier in the paragraph.
D. It provides a specific example of the type of data collected in the experiment described earlier in the paragraph.
E. It anticipates a potential objection to the conclusions drawn by the researchers involved in the experiment described earlier in the paragraph.
Q3: The primary purpose of the passage is to
A. describe some procedures used for wildlife management and consider
some problems associated with the execution of those procedures
B. outline a problem related to a wildlife management procedure and offer
potential explanations for the results of an experiment bearing on that problem
C. present experimental results that illustrate the need for certain wildlife
management procedures and point out some inconsistencies in those results
D. argue that a certain procedure used for wildlife management should be
modified because of its unintended consequences
E. propose that further experiments be performed to assess the long-term effects of certain wildlife management procedures
Last edited by singh_amit19
on 17 Oct 2007, 10:18, edited 3 times in total.