《生物与气候》课件

生物地理學氣候陸生生態系1風—

地球循環系統的重要部份2地理生態學Todoscienceistosearchforpatterns,notsimplytoaccumulatefacts,andtodothescienceofgeographicalecologyistosearchforpatternsofplantandanimallifethatcanbeputonamap.3氣候Weather任何時間地點的溫度,壓力,溼度,降水,日照,雲量,風向,風速等物理特性Front兩個具不同溫度與密度的氣團的交界4氣候WarmFront暖空氣密度較低,遇冷空氣上升凝結成雲,逐漸厚實後雲層降低,釋放其濕氣時將飄小雨ColdFront冷空氣密度較高,於暖空氣下方呈楔形,被推擠向上的暖空氣凝結成大水滴,常有雷雨形成56氣候Tornado龍捲風於陸地上快速形成難以預測Tropicalcyclone熱帶暴風於海上長期形成可追蹤其路徑與風速生成於大西洋稱颶風,於太平洋稱颱風789氣候Climate長期的天氣狀況,平均溫度與平均雨量為決定氣候的兩個重要因子1011氣候氣流與氣候1.地表受熱不均2.地球軸線(假想線)為傾斜3.地球自轉4.太陽能量的偶發性衝擊地球5.空氣與水的特性1213141516洋流與氣候17181920溫室效應21Rainshadoweffect22SeaandLandBreezes23地球的主要生態系24溫度雨量與生態系25溫度雨量與生態系26海拔緯度與生態系27世界主要沙漠分布2829Twomajorbands:30oNand30oS.Occupyabout30%ofearth’slandsurface.Waterlossexceedsprecip.mostoftheyear.Soilusuallyextremelylowinorganicmatter.Plantcoverrangesfromsparsetoabsent.Animalabundancelow,butbiodiversitymayberelativelyhigh.Strongbehavioraladaptations.Humanintrusionincreasing.30人類對沙漠的衝擊31世界主要草原分布3233TropicalSavannaOftenoccurimmediatelyN/SofRainForests.Climatealternatesbetweenwet/dryseasons.Droughtassociatedwithdryseasonleadstodryconditionsandsubsequentlightning-causedwildfires.Soilshavelowwaterpermeability.Saturatedsoilskeepstreesout.Increasingpressuretoproducelivestock.3435TemperateGrasslandExtremelywidespreaddistribution.Annualrainfall300–1,000mm.Experienceperiodicdroughts.Soilstendextremelynutrientrichanddeep.Thoroughlydominatedbyherbaceousvegetation.Largeroamingungulates.Bisonvs.cattle3637TundraCoversmostoflandsNofArcticCircle.Climatetypicallycoolanddrywithshortsummers.200-600mmprecip.Lowdecompositionrates.Supportssubstantialnumbersofnativemammals.Humanintrusionhistoricallylow,butincreasingasresourcesbecomescarce.38人類對草原的衝擊39世界主要森林分布404142TropicalRainforestsMostoccurwithin10olat.ofequator.Littletemp.variationbetweenmonth.Annualrainfall2,000–4,000mmrelativelyevenlydistributed.Heavyrainfallquicklyleachessoilnutrients.Organismsaddverticaldimensiontoecology.Harborstaplefoodsandmedicinesforworld’shumanpopulations–increasinglyexploited.43LatitudinalGradientsinSpeciesRichnessMostgroupsoforganismsaremorespecies-richinthetropics.

Browngroupedhypothesesintosixcategories:

TimeSincePerturbationMorespeciesinthetropicsbecausetropicsareolderanddisturbedlessfrequently.Moretimeforspeciation,andlessfrequentdisturbancereducesextinctionrate.44LatitudinalGradientsinSpeciesRichnessProductivityHighproductivitycontributestohighspeciesrichness.Moreenergytodivideamongpopulation.EnvironmentalHeterogeneityMoreheterogeneitythusmorepotentialhabitatareasandniches.45LatitudinalGradientsinSpeciesRichnessFavorablenessTropicshavemorefavorableenvironments.Noextremestolimitdiversity.NicheBreadthandInterspecificInteractionsVariousthemesBrown

suggeststhatultimatecausesmustbyphysicaldifferences.46LatitudinalGradientsinSpeciesRichnessSpeciationandExtinctionRatesRosenzweigproposedimmigrationcanbelargelydiscountedatbroadscales,thusspeciationwillbeprimarysourceofnewspecies.Speciesremovalviaextinction.Tropicsrichnessisgreaterduetohigherratesofspeciationand/orlowerratesofextinction.4748TemperateForestMajorityliebetween40oand50o.Rainfallaverages650–3,000mm.FertilesoilsLonggrowingseasonsdominatedbydeciduousplants.Shortgrowingseasonsdominatedbyconifers.Biomassproductioncanbeveryhigh.Manymajorhumanpopulationcenters.495051BorealForest(Taiga)ConfinedtoN.hemisphere.Covers11%ofearth’slandarea.Thin,acidicsoilslowinfertility.Generallydominatedbyevergreenconifers.Relativelyhighanimaldensity.Historically,lowlevelsofhumanintrusion.52人類對森林的衝擊53MountainBiomesMakeupalmostafourthoftheworld’slandsurface.Containthemajorityoftheworld’sforest.Regulatetheearth’sclimatewhentheirsnow-andice-coveredtopsreflectsolarradiationbackintospace.Playacriticalroleinthehydrologicalcycle.54人類對山地的衝擊55ThreeMajorLessonsDifferent