GG354 Final Exam Review Package.docx

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Department
Geography
Course
GG354
Professor
Geographyand Environmental
Semester
Winter

Description
Not all lessons include text book readingsLesson 4 readingThe Evolution of Polar Desert and Tundra EcosystemsKonrad GajewskiNature of Arctic ecosystemsLeast diverse terrestrial ecosystem in the worldLow amounts of energyNature of the EnvironmentInfluenced my meso and microclimates affected by topographic and geomorphic variabilityClimate is determined by general circulation not necessarily isothermsTopography is regional determines by bedrock and historyLow precipitation low areas have higher plant density from runoffNutrient poor bedrocklow plant growth and densityWhere there is animal and human activity there is an abundance of vegetationArctic soils are considered Gelisols or Cryosols permafrost in upper 2 mCoastal tundraHistosols soil with thick accumulations of organic matterShort growing season and cold temp slow the process slow nutrient cycleEcology of Arctic PlantsCharacteristics that allow plants to survive in the arctico Prostrate growth form protected by snow warmer near the groundo Conserve nutrients less waste of resourceso Rapid growth with snowmelt use resources as long as possibleo Can tolerate snow during growing seasono Ability to live with low nutrientsDubious and ever green shrubs cushion plants sedges and grasses and other herbaceous plantsPerennial plantsChallenge for sexual reproduction pollen dispersal is difficultPlants were dispersed across the arctic after deglaciationDisturbance is common in the Arctic plants show signs of cryoturbation and frost heaveITEX project started late 1980s monitors impacts of climate change on vegetationFactors that limit plant survivalo Tempo Length of growing seasono Watero Nutrient availabilityo Solar radiationo Windo Interaction of a few of theseSummer temps are very important in plant metabolism small change in temp canalter growthLength of growing season effects sexual reproduction very short mid june augustLow precipitation affects the plants specifically in the High Arctic need summer moisture to survive the wintero Permafrost can form a barrier to water drainage and soil may become saturated low arcticStrong surface winds because of the lack of plant canopy increase transpirationo Abrasion of sediment transportedo Helps spread seedsSolar radiation affects the plants as well complicated by canopy effectIncrease in nutrients increase growth and reproduction in the short term long term needs to consider other factors such as soil temp nutrient cycle rates grazing frost sensitivityYet no evidence of nutrient deficiency in Arctic PlantsVegetation ZonationMacroclimate plant diversity is associate with summer temps3 subdivisions of Arctic Vegetationo low Arctic tundramore plant diversitynot circumpolartreeline is where the forest meets the tundrao middle Arctic polar semideserttransition zoneo high Arctic sparselyvegetated polar desertcircumpolar plantsmostly herbaceous plants few low prostrate shrubso distinguished by floristic and physiognomic characteristicso Foresttundra where the forest meets the Arctic treelineTreecover over entire landscapeSpruceArctic OasesSeveral areas in the High Arctic where plant production and biodiversity is greater than what is found in the polar desertcalled oaseso Can be defined as sites with more than 50 cover in an otherwise polar deserto Extensive muskox populationo Warmer climate due to mountainso Lowlands with higher soil moisture temp and radiationo Temps have been recorded on Ellesmere Island the same as the Low arctico Devon Island Oasis Truelove lowlandSedgemoss meadows97 different plant specieso Hot Weather Creek on Fosheim PeninsulaHigh amounts of moisture from precipiation and melting of ground iceLongTerm evolution of Canadian Arctic EcosystemsArctic flora is recent since late TertiaryDeveloped from many deposits during the PaleoceneAlso due to the connection with Asia and EuropeFossil forest of Axel Heiberg Island Eocene VegetationChanges in the earth during this timeo Uplifting of Tibetan plateau and rocky mountainso Separation of the Atlantic and Pacific oceanso This caused north and south temp gradient to increaseo This caused the current vegetation to be how it is todayThe dominant tree was Metasequoia now found in China and Japano During this time period it was much warmer there was less freezing and lack of gaciers and snowfallThe flora of the Oligocene related more to Asiao General climate deterioration and fluctuationso Broadleaf evergreen during this erao Increase in broadleaf deciduousMiocene erao More taxa than most other places on eartho Evergreen and deciduous increase in coniferso Connection with Asia created a more diverse forestPiloceneo No strong evidence of tundra it was developing further northo Increase in ice sheets killing treesThe QuaternaryPeriod of planetary cooling alternating glacial and interglacial periodsNot a lot is known during the early parts of the Quaternaryo Isolated terrestrial depositso Warmer as summer insolation was greater than it is todayTundra was constantly covered and uncovered by ice sheetsPlants displaced even from Asia to north America as sea levels were lower AmphiAtlantic plants only found in northern Europe and Greenland but may haveoriginated from CanadaPost Glacial Climate and Vegetation Change in arctic CanadaThe Canadian Arctic postglacial climate is determined by a variety of recordso Long term cooling past 30004000 yearso Millennialscale climate variabilityo Warming since 1850sVariability within decade and centuryo Response of climate system to changing topography melting of ice sheetso Seasonal and latitudinal distribution of incoming solar radiationo Other factors such as changes in volcanic activity solar variability and greenhouse gaseso All of these affect the flora and fauna during a given timeWarm period directly after deglaciation early Haloceneo Several plant taxa were growing further north than where they can survive now
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