280 likes | 559 Vues
UNDERC HABITATS (terrestrial & aquatic). CHANGE CONTINUES. EVOLUTIONARY AND GEOLOGICAL CHANGE (inherent) ECOLOGY OF AQUATIC HABITATS (inherent) ECOLOGY OF TERRESTRIAL HABITATS (inherent) HISTORICAL CHANGES WITH HUMANS (Native Americans and Europeans) – environmental history. FORESTS
E N D
UNDERC HABITATS (terrestrial & aquatic)
CHANGE CONTINUES • EVOLUTIONARY AND GEOLOGICAL CHANGE (inherent) • ECOLOGY OF AQUATIC HABITATS (inherent) • ECOLOGY OF TERRESTRIAL HABITATS (inherent) • HISTORICAL CHANGES WITH HUMANS (Native Americans and Europeans) – environmental history
FORESTS (taught by Dr. Walt Carson, U. of Pittsburgh) AQUATICS (taught by Dr. Todd Crowl, Utah State U. & NSF)
Aquatic Environments • Oceans • Coastlines/Estuaries • Streams • Lakes • Wetlands: bogs and fens
Streams Open systems, constant input of water and nutrients Precipitation flows into streams via 2 routes: • Overland flow through surface runoff • Infiltrating soil surface, then flowing underground and into streams as groundwater Types of flow – permanent, intermittent, interrupted
Watershed The area that a stream drains, a.k.a, drainage basin, or catchment area UNDERC area is near continental divide between Great Lakes drainage basin and Mississippi River basin Water flows downhill • Upstream • Downstream
River Continuum Hypothesis Predictable structure of river (physical features, dominant organisms) from upstream “headwaters” to downstream
Lakes May be created by a variety of geologic and climatic events: • Movement of tectonic plates • Volcanic eruptions • Landslides • Fluvial processes • Glaciation
Lake StratificationDifferent zones or layers due to water temperature and water density
Lake StratificationDifferent zones or layers due to water temperature and water density
Nutrients Temperature not the only stratified element of a lake • Oxygen: highest concentration near surface (photosynthesis) • Nitrogen: NO3- at surface, NH4+ at benthos • Sulfur: SO4 at surface, H2S at benthos • Iron: Fe+3 at surface, Fe+2 at benthos
Aquatic Succession Oligotrophic Lake Mesotrophic to Eutrophic Lake Sphagnum Marsh (Eutrophic) Bog (Dystrophic) Terrestrial
Wetlands: technical definition Vegetation • presence of “hydrophytic” (water-loving, flood-tolerant) plants Soils • presence of “hydric” (flooded, reduced) soils Hydrology • water table at or near the surface for part of the growing season
Wetland examples • Marshes • Swamps • Glades • Bogs • Fens
Acidic (pH < 4.1) Nutrient-poor soils Ombrotrophic: precipitation-fed system Dominant vegetation: Sphagnum moss, Vaccinium (cranberries and blueberries), and other low-lying species Slightly less acidic (pH 4.1-6.0) Soil more nutrient-rich Minerotrophic: groundwater-fed system Dominant vegetation: sedges, rushes, and grasses Fens Bogs
Ecological succession results in change over time as lakes gradually become terrestrial habitats.
Succession in Terrestrial Plant Communities After a community reverts from aquatic to terrestrial, succession continues resulting in successive species replacements until a climax community is established. The species composition of the climax community is determined by climate.
TYPES OF SUCCESSION • PRIMARY -- from bedrock (no soil) through a series • of communities (seres) to climax. • SECONDARY -- successional progression is pushed back • by a disturbance to a point where soil still exists • and then proceeds. • What did the glaciers do at UNDERC? • What does a large windstorm do? • What does aquatic succession represent?
White Pine Hemlock Other Modeling Forest Dynamics(SimForest, a simplified version of JABOWA, a model by Dr. Dan Botkin,http://ddc.hampshire.edu/simforest/you will try to parameterize the model for UNDERC, learn about it to be prepared) 2% 10% 88% 0.08 trees/m2
CHANGES WITH FOREST SUCCESSION
ANIMALS CAN MODIFY FORESTS & AQUATIC HABITATS
FROM A CONSERVATION PERSPECTIVE: WHAT FOREST & AQUATIC HABITAT AGES DO WE WANT TO ENCOURAGE?