首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Recently, researchers investigated the foraging profiles of bird species in two separate eucalyptus forests in Australia: Dryand
Recently, researchers investigated the foraging profiles of bird species in two separate eucalyptus forests in Australia: Dryand
admin
2021-09-28
68
问题
Recently, researchers investigated the foraging profiles of bird species in two separate eucalyptus forests in Australia: Dryandra in Western Australia and the Southern Tablelands, roughly 3000 km west in New South Wales. Despite their geographical separation, there is a broad overlap in species between the two locations. However, at Dryandra, a much larger proportion of species (61 percent) than at the Southern Tablelands (34 percent) are ground foragers.
The high proportion of ground foragers in Dryandra might be explained by the openness of habitats there, that is, the absence of dense ground vegetation, and the lack of a continuous shrub layer. Ground foraging appears to be facilitated by an open habitat with area of bare ground. However, the researchers found that the Tablelands were also open with sparse to dense litter layers, abundant in woody debris, and had discontinuous or absent ground and shrub layers. Thus, differences in habitat structures between these areas and Dryandra cannot entirely explain the greater abundance of ground foragers in Dryandra.
The researchers offered several hypotheses to explain the difference. First, there may be important differences in habitat structure that are not revealed by casual observation. For example, differences in tree heights and
canopy complexity
may contribute to differences in species richness and foraging behavior among bark- and foliage-foraging birds. Second, despite structural similarities, it is possible that there are differences between habitats in the abundance or availability of litter and ground-dwelling prey. Such differences, if they exist, may indicate fundamental differences between eucalypt ecosystems in how and where energy and nutrients are cycled, as well as in overall productivity. Finally, the differences in foraging profiles between Dryandra and Tablelands may be the result of historical changes in bird species as a consequence of changed grazing and fire regimens, the impact of introduced predators, such as
foxes and feral cats
, and logging following European settlement.
The greatest impact of these processes is on ground-foraging and ground-nesting birds.
Dryandra has not been free of these changes, but the impact may have been less or more recent with the result that Dryandra may retain a more natural or complete bird diversity relative to the Tablelands.
The passage suggests which of the following about “canopy complexity”?
选项
A、Decreased canopy complexity can lead to a greater abundance of ground foragers.
B、Increased canopy complexity usually helps in retaining a more natural bird diversity.
C、Increased canopy complexity is usually detrimental to ground-nesting species.
D、Differences in canopy complexity between two regions are not always obvious.
E、Differences in foraging behavior among foliage-foraging birds can lead to differences in canopy complexity.
答案
D
解析
第三段第二句表明两个地方的栖息地结构差异可能不容易被发现。第三句列举的便是这种不容易被发现的结构差异:树木高度和树冠复杂性,因此选项D正确。A项有的考生可能会觉得,树冠复杂性降低表明以树叶为食的鸟类只能来到地面觅食。但是文中并没有说树冠复杂性到底会增加还是减少地面觅食者的数量,因此选项A不能选。
转载请注明原文地址:https://kaotiyun.com/show/uGVO777K
本试题收录于:
GRE VERBAL题库GRE分类
0
GRE VERBAL
GRE
相关试题推荐
Excessinventory,amassiveproblemformanybusinesses,hasseveralcauses,someofwhichareunavoidable.Overstocksmayaccum
Nearlyacenturyago,biologistsfoundthatiftheyseparatedaninvertebrateanimalembryointotwopartsatanearlystageof
In1977theprestigiousEwhaWomen’sUniversityinSeoul,Korea,announcedtheopeningofthefirstwomen’sstudiesprogramin
Damagednervesinthespinalcorddonotregeneratethemselvesnaturally,norevenunderthespurofnerve-growthstimulants.Th
Themostwidelyusedtherapyforacertaintypeofulcercompletelyhealssuchulcersin44percentofpatientswithinsixmonth
2.Spidersofmanyspecieschangecolortomatchthepigmentationoftheflowerstheysiton.Theinsectspreyedonbythosesp
Efficiencyandredundancyarecontradictorycharacteristicsoflinguisticsystems;however,theycanbeusedtogethertoachieve
Itwaslongthoughtthatanow-rarediseaseofthejoints,alkaptonuria,wasepidemicinEgypt2,500yearsago.Evidencecamefr
CharlottePerkinsGilman,alatenineteen-centuryfeminist,calledforurbanapartmenthousesincludingchild-carefacilitiesan
WhatistheapproximatemeasureofthecentralanglerepresentingAtkinsdietersin1995?
随机试题
患儿,4岁。右前臂骨折后行石膏管型固定,2小时后出现手部苍白、发凉,桡动脉搏动减弱,不让人碰右手手指,一碰即大哭不止。在确诊后,对此并发症最有效的处理措施是
甲、乙、丙、丁、戊拟共同组建一饮料有限责任公司,注册资本200万元,其中甲、乙各以货币20万元、30万元出资;丙以实物出资,经评估机构评估为40万元;丁以其一项高新专利技术出资,作价100万元;戊以劳务出资,经全体出资人同意作价10万元。全体股东首次出资额
(2008年)匀质杆AB长l,质量m,质心为C,点D距点A为,(见图4—53)。杆对通过点D且垂直于AB的轴y的转动惯量为()。
雇主在评价建议书时,尤其重视()。
大跨度悬索桥的刚架式桥塔通常采用()。
在FIDIC于1999年出版的新型合同条件下,没有业主委托的工程师这一角色的合同条件是()。
下列关于年金的说法中,正确的有()。I.教育费支出属于期初年金Ⅱ.期初年金的现值大于期末年金的现值Ⅲ.期末年金的终值大于期初年金的终值Ⅳ.房贷支出属于期初年金
下列学派、代表人物及其教育思想对应错误的是()
ExploretheScottishHighlandswithBaketbahTravelandTours!Ifyou’relookingforafunandeducationaltourof
Wheredoestheannouncementtakeplace?
最新回复
(
0
)