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Altitudinal Gradients

Altitudinal Gradients

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Altitudinal Gradients

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  1. Altitudinal Gradients • An increase in altitude (elevation) mimics a progression towards northern biomes

  2. Altitudinal gradient on a tropical mountain

  3. In Western Maine and New Hampshire… • At the mountain base, northern hardwood species (sugar maple, American beech, yellow birch) or oak hardwood species • Spruce and balsam fir forests further up • Krummholtz “sub alpine” zone - stunted, dwarf trees, often flagged • Alpine zone - above treeline (grasses, lichens, specialized plants)‏ • Drastic changes in plant communities and forest structure

  4. Alpine Communities • Very rare (<5% of terrestrial habitat on planet)‏ • Very similar species to tundra biomes • Mount Washington biggest alpine zone east of Mississippi (Mt. Katahdin is second). • Plants remenants of last glacial retreat (9000 years ago)‏ • Very fragile (easily trampled by humans)‏ • Endemic plant species present • Threated by warming trend (global warming)‏

  5. Alpine Vegetation • Low lying (cushions) for protection against snow • Have thick, waxy leaves to prevent wind/snow damage • Alpine plants can tolerate extremes in environment (drying winds, acidic soils, scant water, ice coating)‏ • Evergreen leaves to save energy of foliation in spring

  6. Moss CampionSilene acaulis

  7. Alpine Azalea

  8. Diapensia lappocona

  9. Cladina stellarisStar-tipped reindeer lichen • Lichen - mutualism between algae and fungi • Attaches to hard substrates (rocks, trees)‏ • Nutrients from air and photosythesis • Bioindicator • Cladina stellaris important food for caribou

  10. Birds of the Alpine Zone • American Pipit • Rare in the East • Only nests on Katahdin and Presidentials

  11. Mammals • Caribou once roamed throughout New England’s alpine zones • Extirpated by turn of century • Reintroduction to Baxter State Park failed in 1980s

  12. What we will do on Bald Face? • Measure canopy height • Measure % canopy cover and light intensity • Record tree species and diameter (dbh) in 10x10 meter plots • Collect a soil sample and measure horizons • Record height and % cover of forest layers (herbacious, shrub, subcanopy, canopy)‏ • Identify plant species (herbs, shrub, fern, etc)‏ • Determine Stand Age • Incidental mammals, herps, birds