Noting that bison herds appear to graze selectively in areas occupied by prairie dog colonies, Coppock hypothesized that the att

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问题     Noting that bison herds appear to graze selectively in areas occupied by prairie dog colonies, Coppock hypothesized that the attraction is due to improved forage quality: prairie dogs’ own grazing activities alter herbage dynamics, plant species composition, and nutrient cycling. The colonies’ territory contains relatively little low-quality mature standing herbage and is characterized by communities of plants that are high in crude protein and highly digestible. However, such effects are not produced only by prairie dogs. Willms showed that sites selectively grazed by cattle had reduced standing dead plant material, altered species composition, and increased soil nitrates, ammonium, and available phosphorus. In fact, long-term, intensive use by any grazer will cause comparable changes in plant communities.
The author of the passage would most likely agree with which of the following statements about mature standing herbage?

选项 A、It tends to be fairly easy for grazing animals to digest.
B、It is likely to predominate at sites with increased soil nitrates.
C、Its abundance at a site will make the site less attractive to bison.

答案C

解析 根据第二句,土拨鼠所在的地方之所以吸引野牛是因为这片区域没有直立牧草,因此这些牧草越多,野牛就越不喜欢这里,选项C正确。
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