What are Ecosystems and Why Do We Need to Protect Them?
Points of Emphasis Ecological Systems are Complex, but Logical Ecosystems are Dynamic, yet Homeostatic Ecological Responses to Humans Varies with Duration of Stress Values of Ecosystems
What is an Ecosystem? Group of interacting organisms and the physical and chemical elements in a defined area. Abiotic Chemicals (CO 2, H 2 O, O 2, NH 3 ) Producers (Plants) Consumers (Animals) Decomposers (Bact.) Sun Temp Moisture
What is an Ecosystem? Group of interacting organisms and the physical and chemical elements in a defined area.
Watershed Hydrology & Sourcesheds Routes of Resources and Contamination
Allochthonous Input Light Nutrients Plants GrazersAlgae Shredders Collectors Predators CPOM/ FPOM Bact. & Fungi Aquatic Ecosystems
Allochthonous Input Nutrients Plants GrazersAlgae Shredders Collectors Predators CPOM/ FPOM Bact. & Fungi Material Cycling
Allochthonous Input Light Plants GrazersAlgae Shredders Collectors Predators CPOM/ FPOM Bact. & Fungi Heat Energy Energy Cycling
Allochthonous Input Light Plants GrazersAlgae Shredders Collectors Predators CPOM/ FPOM Bact. & Fungi Heat Energy Respiration (R) Energy Cycling Balance GPP GPP = R
Allochthonous Input Light Nutrients Plants GrazersAlgae Shredders Collectors Predators CPOM/ FPOM Bact. & Fungi
Allochthonous Input Light Nutrients Plants Grazers Algae Shredders Collectors Predators CPOM/ FPOM Bact. & Fungi
Allochthonous Input Light Nutrients Plants Grazers Algae Shredders Collectors Predators CPOM/ FPOM Bact. & Fungi
Allochthonous Input Light Nutrients Plants Grazers Algae Shredders Collectors Predators CPOM/ FPOM Bact. & Fungi O2O2
Bioconcentration of Contaminants ( Residues of DDT (ppm) in various trophic levels of an estuary food web) Organic Debris ( ) Cladophora (0.03) Plankton (0.04) Marsh Plants ( ) Shrimp (0.16) Mud Snail (0.26) Clam (0.42) Insects ( ) Fish ( ) Fish-eating Birds ( )
Interactions among Organisms and Their Environment Biotic Interactions –Trophic Interactions (i.e. predator/prey) –Competition Intraspecific Interspecific –Disease/Parasitism –Mutualistic Interactions Abiotic Factors (Limiting factors) –Climate Temperature Rainfall Day – Length Seasons –Geology Soils & Water Chemistry Hydrology Soil Moisture –Resources Light Nutrients –Physical Disturbance
Abiotic Regulation (non-resource) of Populations (Species) Environmental Gradient (e.g. Temp) Comp. Level Metabolism (e.g. growth, reproduction) Range of Tolerance Zone of stress
Resource Regulation of Populations Resource Gradient (Light, N, P, Prey) Comp. Level Metabolism (e.g. growth, reproduction) Range of Tolerance Zone of stress
Carrying Capacity (CC) of Populations Time (d, wks, mon, yrs) Population Abundance CC
Carrying Capacity (CC) of Populations Time (d, wks, mon, yrs) Population Abundance CC
Interactions Among Land, Streams, Lakes, and Wetlands Land Lakes Wetlands Streams
Habitat Functions Storage and Transformation – (Water, Nutrients, Sediments) –Settling or Biological Uptake and Retention Transport (Water, Nutrients, Sediments, Biota) Habitat for Spawning/Breeding Habitat for Development of Young Habitat for Adults Productivity Support of Diversity Homeostasis from Interactions
Natural Regulatory Factors & Ecoregions
Natural Sources of Variability Primary Factors –Climate (Temp/Rain) –Geology Secondary Factors –Hydrologic Variability –Soils –Temperature –Water Chemistry –Light Species Membership Competition Predation Mutualism Production Primary Production Secondary Production Nutrient and Energy Cycling Soil fertility Fisheries productivity