首页
登录
职称英语
Neotropical coastal mangrove forests are usually “zonal,” with certain mangr
Neotropical coastal mangrove forests are usually “zonal,” with certain mangr
游客
2025-02-27
19
管理
问题
Neotropical coastal mangrove forests are usually “zonal,” with certain mangrove species foundpredominantly in the seaward portion of the habitat and other mangrove species on the morelandward portions of the coast. The earliest research on mangrove forests produced descriptions ofspecies distribution from shore to land, without exploring the causes of the distributions.
The idea that zonation is caused by plant succession was first expressed by J. H. Davis in a studyof Florida mangrove forests. According to Davis’ scheme, the shoreline is being extended in aseaward direction because of the “land-building” role of mangroves, which, by trapping sedimentsover time, extend the shore. As a habitat gradually becomes more inland as the shore extends, the“land-building” species are replaced. This continuous process of accretion and succession wouldbe interrupted only by hurricanes or storm flushings.
Recently the universal application of Davis’s succession paradigm has been challenged. It appearsthat in areas where weak currents and weak tidal energies allow the accumulation of sediments,mangroves will follow land formation and accelerate the rate of soil accretion; succession willproceed according to Davis’s scheme. But on stable coastlines, the distribution of mangrovespecies results in other patterns of zonation; “land building” does not occur.
To find a principle that explains the various distribution patterns, several researchers have lookedto salinity and its effects on mangrove. While mangroves can develop in fresh water, they can alsothrive in salinities as high as 2.5 times that of seawater. However, those mangrove species found infreshwater habitats do well only in the absence of competition, thus suggesting that salinitytolerance is a critical factor in competitive success among mangrove species. Research suggeststhat mangroves will normally dominate highly saline regions, although not because they requiresalt. Rather, they are metabolically efficient (and hence grow well) in portions of an environmentwhose high salinity excludes plants adapted to lower salinities. Tides create different degrees ofsalinity along a coastline. The characteristic mangrove species of each zone should exhibit ahigher metabolic efficiency at that salinity than will any potential invader, including other speciesof mangrove.
选项
A、refute the idea that the zonation exhibited in mangrove forests is caused by adaption to salinity
B、describe the pattern of zonation typically found in Florida mangrove forests
C、argue that Davis’ succession paradigm cannot be successfully applied to Florida mangrove forests
D、discuss hypotheses that attempt to explain the zonation of coastal mangrove forests
E、establish that plants that do well in saline forest environments requre salt to achieve maximum metabolic efficiency
答案
D
解析
This question asks you to identify the primary purpose of the passage as a whole. The best answer is D. The passage discusses two hypothesis concerning zonation of mangrove forests. Choice A can be eliminated because the passage presents as a viable hypothesis the idea that mangrove zonation may be caused by adaptation to salinity. Choice B is incorrect because the passage is concerned with the causes of zonation patterns, not simple with a description of those patterns. Both C and E contradict information that is presented in the passage.
转载请注明原文地址:https://tihaiku.com/zcyy/3974446.html
相关试题推荐
Homeostasis,ananimal’smaintenanceofcertaininternalvariableswithinan
Neotropicalcoastalmangroveforestsareusually“zonal,”withcertainmangr
Acertainmayorhasproposedafeeoffivedollarsperdayonprivatevehiclese
Certainmessengermoleculesfightdamagetothelungsfromnoxiousairbytellin
Themostwidelyusedtherapyforacertaintypeofulcercompletelyhealssuchu
AuthoritiesinCaliforniarequireddriverstousetheirheadlightsonacertain
LikemostothercoastaltownsinNorway,thetownofStavangerwasquietandpea
AcertaintypeofdinnerwaremadeinGanandiacontainslead.Leadcanleachinto
Acertaintypeofshrimphabituallyhoversaroundsuperheateddeep-seageysers,
Fromacertainfarmingregion,truckscancarryvegetablestomarketinNewMexi
随机试题
Criticismofresearchlaysasignificantfoundationforfutureinvestigative
AhandwrittennotefromAlbertEinsteinsoldformorethan$1.5million
肥胖obesity;fatness
A.水分测定B.灰分测定C.膨胀度的测定D.酸败度E.色度检查主要用于含黏液质、
左边给定的是多面体的外表面,右边哪一项能由它折叠而成?请把它找出来。 A.如上
拟开挖一高度为8m的临时性土质边坡,如下图所示。由于基岩面较陡,边坡开挖后土体易
菊花的明目作用是A.平肝明目 B.清肝明目 C.养肝明目 D.疏风明目
华星公司成立于2011年,是一家致力于汽车零配件研发、生产及销售的公司。201
计划成本核算体系下,本期发出材料应负担的成本差异应按期(月)分摊结转。()
说明事物在时间上的变化和发展趋势的指标是A.比例 B.百分率 C.相对比
最新回复
(
0
)