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Unformatted text preview: Exam 2 Tuesday Nov 3 Exam
Today and next week:
1. Mid-latitude Grasslands 1. 2. D climates: • Humid Continental climates (D) • Subarctic climates (D) 3. E Climates • Arctic and Alpine Tundra (E) • Polar Ice Caps (E) 4. Highland (H) Be there! Tall-grass Prairie, Ohio Mid-latitude (Temperate) Grasslands: a naturally treeless ecosystem
-continuous cover of grass -mostly perennial grasses (come back every year) Tall-Grass Prairie—Kansas Flint Hills Tall Humid Continental-Dfa Geography: Vast in extent, esp. in N. Am and Eurasia. Geography: Temperate Grasslands exist mainly in 2 climate types 1. Steppe (semi-arid, BS) (short grass steppe) (semi-arid, 2. Humid Continental (D) (mixed- and tall grass prairies) (mixed- *Remember TROPICAL grasslands are Tropical Savanna (Aw) TROPICAL 3 types Pre-settlement Pre N. American Prairies: N. Short, Mid, Tall Grass Short Mid Tall Grass height varies with Grass precipitation gradient precipitation Tallgrass Mixed grass Short grass Some images of different prairie types…. Short-Grass Prairie—Ft. Collins, CO—Steppe (BS) Short Short grass prairie—N. Dakota, near boundary between Short Humid Continental (D to the east) and Steppe (BS to the west) Humid Mid Grass Prairie with large grazers, Nebraska Mid Humid Continental Tall Grass prairie, Kansas Flint Hills (Humid Continental-D) Tall Tallgrass prairie, Humid Continental; often grows higher than your head! Michigan Ontario, Canada
Illinois Pre-Settlement Prairies Why grassland in Illinois and Indiana? Can’t trees grow there? Tallgrass Mixed grass Short grass Prairie Peninsula: A RECENT ECOSYSTEM formed during the Prairie Hypsithermal Period 8000—4000 yrs BP (Before Present) a warmer-drier period, bad for trees—good for grasses Became cooler and wetter after 4000 BP, but prairies were still there when Europeans arrived ….WHY? Prairie peninsula maintained until European arrival by Indian burning, probably combined with buffalo grazing burning, Fire and grazing help maintain Tall Grass Prairie like in Tropical Savannas—kills trees and favors grass Without fire, some moist grasslands may convert to forest Prairie restoration by tree removal, Squaw Creek, Iowa Without Indian burning, trees grew Without in former tall-grass prairies Prairie restoration through a controlled burn, WI Prairie Tall Grass Prairie is a NEARLY EXTINCT ecosystem: Less than 0.06% of original tall grass prairies in N. America remain What happened to them? Tall-Grass Prairie, Ontario Tall Pretty much all tall grass prairie has been converted to Pretty agriculture agriculture Best soil for agriculture! Mollisol soil type Southern Minnesota Dark, fertile Mollisol soils develop Mollisol develop under temperate grasslands under -Organic and Nutrient rich 1837 John Deere invented steel-bladed plow…. Most tall grass prairies disappeared within 50 years Tall Grass Prairie Peninsula has nearly disappeared Last Evolved First Dissolved Ecosystem in North America Key Point Key Of ALL biomes, Of biomes, Mid-Latitude Latitude (temperate) Grasslands are Grasslands are the MOST MOST heavily heavily modified by humans humans Questions on grassland? Microthermal (D and E) climates are next! Microthermal Climates (D)
*Key: Have at least 1 month below freezing, Snow is common Have month 1. Humid Continental — hot/warm summer, cold winter 1. 2. Subarctic — cool summer, VERY cold winter 2. Subarctic Geography: Subarctic D climates are at higher latitudes or in more continental locations than Humid Continental Humid Humid Humid Cont. Cont. SubSubArctic Arctic Hmmm…D climates are conspicuously climates missing from…? missing 2 Classic Classic Humid Humid Continental Continental (D) Climates New York, 40°N New Moscow, 55°N Moscow, Humid Continental
• No dry season (thus “Humid”) • At least one month below freezing but warm summer (thus “Continental”) How do you expect Moscow (55°N) to compare with NY city (40°N)? Humid Continental Humid Continental • drier, more extreme, WHY? Much of the winter precipitation falls as snow in Humid Continental climates and lakes commonly ice over Continental Plants can’t use water locked use up in ice, so they experience drought if all precip is frozen precip 4 major vegetation types in Humid Continental climates
Needleleaf Grass Broadleaf Mixed Forest But remember, most of the grasslands are gone to farming Examples of Humid Continental vegetation… Mixed forest, Vermont Hardwood forest, KY Pine Forest on sandy soils in WI Agriculture DOMINATES the Agriculture DOMINATES Humid Continental landscape Humid Major Crops: Major • corn • soybeans • wheat • hay hay The plant crops feed The people AND the animal crops: Dairy, Beef, Hogs Commercial forestry is less important, except in very cold areas (highest Commercial (highest latitudes of Humid Continental), mountains, and wet/poor soil areas that latitudes eas are unsuitable for food crops unsuitable Subarctic climates (E) - higher latitudes >50º climates higher >50º
…and very continental locations a little lower 40° Humid Cont Humid Cont SubSubArctic Arctic • Very low precip = virtual desert; Cold air is dry! Very precip How can we describe patterns of temp,winters—steep curve! rainfall, seasonality? How short summers and long COLD winters—steep • Very Subarctic The SUBARCTIC climate has a homogeneous cover of The coniferous forest called BOREAL (N. Am) or TAIGA (Russia) =Vast needle-leaf forests that =Vast needle that needle-leaf cover 11% of earth’s surface cover earth’s –25% of earth’s closed-canopy forest –25% earth’s closed-canopy Plant adaptations: 1. Conifers have conical shape that sheds snow and keep branches from breaking Any ideas on plant adaptations in Boreal climates? Russia Russia Boreal-type forest exists not only at high latitudes but also high Boreal altitudes. Pikes Peak, CO (elevation ~12000 ft). Other advantages of conifers (evergreen needleleaf trees) over Other broadleaf trees in biome with short summers and long winters? 2. Needles have reduced surface area, thus lower water loss during winter winds and drought (frozen) 3. Conifers don’t lose leaves; can immediately photosynthesize and grow more quickly when weather warms (good in places with few warm days) Some Boreal areas, primarily southern, have broadleaf Some (hardwood) trees along with conifers: Mixed Boreal forest (hardwood) Other Biome Characteristics: 1.. Low plant growth rate, relatively low biomass, sm. trees 1 2. Relatively low biodiversity
Alaska Low evaporation causes lots of bog Low and pond formation Subarctic landscapes are poorly suited for agriculture Subarctic • Growing season too short • Poorly developed wet soils, acidic, decomposition slow Major economic activities (and ecosystem disturbances) in Major Subarctic regions: Subarctic 1. Timber and pulpwood production from vast boreal forests 2. oil and gas wells
Potential Also Also Production •Hydroelectric •Mining As you move poleward, what biome do you come As to when you run out of boreal forests? Tundra (E) – means a treeless, plain Tundra Tundra Geography: High latitudes mostly well above 60° Check out the southern hemisphere: No Tundra, no Subarctic, no Humid Continental No Subarctic Found at BOTH High Latitudes (Arctic Tundra)… Arctic tundra, Alaska … and High Altitudes (Alpine Tundra) and High Cushion plants Alpine Tundra in Rocky Mountain N.P. Note distinct treeline on distant mountains treeline In Tundra MAX mean temps barely > freezing! Very dry In High-llat tundra controls: Stable H Press & dry cP air masses at cP What large-scale features (controls) most influence climate? Low temps =“Permafrost” Low =“Permafrost”
Soil that stays permanently frozen -surface goes through freeze/thaw cycles -surface Tundra vegetation has NO trees due mainly to short Tundra growing season and permafrost (deters roots) Permafrost defines where trees grow, treeline occurs where Permafrost
continuous permafrost is present Melting permafrost collapses ground “drunken trees” Low Growing Plants (grass, mosses, lichens, low shrubs) – adapted to low temps, wind, poor drainage Tundra Vegetation Tundra • simple structure • low biomass • low diversity Tundra not great for tea-cup poodles! Large body size is a good adaptation to cold temps. What do all these tundra (and boreal forest) animals have in common? What group of animals are missing in tundra environments? What Reptiles and amphibians are rare or absent-record for a reptile is 54° S Reptile that lives at high latitude. Cold-blooded
Body temp depends on outside conditions Wood frog- Only frog to live in Arctic circle Human activities and impacts are relatively low in Tundra, but it is a fragile habitat not well able to repair itself. Greatest negative impacts are from Mining and Oil Drilling (Russia, Greenland, Canada, Alaska) -ground and water pollution and especially oil spills What kind of human activities What affect tundra? Tundra areas are rich in minerals! Oil, gold, zinc, nickel, Tundra copper, coal…can pollute ground and water copper, Oil spill on Alaskan oil pipeline Oil Gold mining in AK Another impact: indigenous people in Norway, Finland, Sweden, Russia who do traditional reindeer husbandry; Reduces Forest Overhunting is a problem in some areas and for some animals: Large numbers of musk oxen in Greenland, Canada, Alaska were hunted nearly to extinction in mid 1800s by non-native whalers Musk oxen are making a slow comeback in Alaska Other examples of overhunted tundra species: overhunted Caribou, arctic fox, whales Climatic warming and melting polar ice threatens polar bears, some seals, indigenous cultures indigenous
A few links: Bloomberg Daily Mail-UK article NRDC Discovery NY Times NSIDC Many scientists see Many the Arctic as the “canary in a coal canary mine” for the earth. mine What is the landscape like poleward of the Arctic tundra? Just ICE! Just The Ice Caps (EF) Tundra Ice Cap Geography: Antarctica and Greenland (in middle) NO months above freezing, almost no precip - Polar deserts! NO precip Highland Climates Highland Too complex for global scale maps Distribution of Major Highlands Distribution • Note absence of major highlands in Australia Snow and Glaciers at the EQUATOR?
A brief note on Altitudinal Zonation… Mt. Kilimanjaro 3° S, Tanzania, Africa Altitudinal Zonation Altitudinal “Tropics to Tundra” Altitudinal zonation of crops Humans live in even some of the highest highlands Village in Himalayas Faces age rapidly in high UV at high elevations (little filtering in low density air) Man in Nepal Himalaya Mountains 16 years old ☺ Yak dung is used for fuel because of lack of wood Stacks of dried yak dung, Tibet For your studying pleasure: General Relationship between Biomes and Climate factors
tropical deciduous forest Mid-Lat Mixed Forest Mid Questions? Questions? The “Death Road” in Bolivia ...
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This note was uploaded on 04/09/2010 for the course GEOG 1104 at Virginia Tech.