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
8
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
Whenbotheredbyotheranimalsorhumans,somespeciesofhornedlizardswillpo
A$10bill(1,000cents)wasreplacedwith50coinshavingthesametotalvalue.
Thehumanbodyissuitablydescribedas"ahighlycomplexself-generator"b
请阐述弗洛伊德的人格结构说。
驾驶汽车在山区道路下陡坡时,怎样利用发动机制动控制车速?()A.挂入空挡 B
可致儿童昏迷及惊厥()A:氯霉素 B:维生素A:C:抗组胺药 D:苯妥英钠
对尊重病人自主权的正确理解是()A.必须听从有地位的患者的决定 B.此准则适
厚朴“燥湿消积、行气平喘”功效相关的药理作用不包括的是A促进消化液分泌 B抑制
瞬时记忆的信息储存方式具有鲜明的()。 A.形象性B.直观性 C.抽象性
处理工程质量事故,有时需要通过定期检测才能得到结论。对此,项目监理机构应与建设单
最新回复
(
0
)