Module 3. Basic Ecological Principles

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1 Module 3. Basic Ecological Principles Ecosystem Components Abiotic Biotic Species & Habitat The Biomes of North America Communities Energy & Matter Cycles in Ecosystems Primary Productivity Simple Ecosystem Models Terrestrial Biomes of North America Patterns driven by atmospheric circulation & geography green = low chlorophyll = low productivity red = high chlorophyll = high productivity resource availability is controlled by weather and landscape vegetation zones mirror these resources Biology 105 Module 3 1

2 Terrestrial Ecoregions of the United States Eastern broadleaf Everglades climate establishes distinct biomes or ecoregions on land these are characterized by distinct vegetative assemblages Biomes Across the United States Water availability across the 39 th parallel 15,000 10,000 5,000 precipitation chaparral coniferous coniferous prairie desert shortgrass tallgrass prairie deciduous water availability is controlled by prevailing climate & geography regional & local water availability influences vegetation Biology 105 Module 3 2

3 Latitude & Altitude Influence temperature regimes latitude polar ice tundra coniferous northern deciduous tropical s altitude vegetative zonation occurs in response to temperature regimes temperature influences water and nutrient availability Nutrient Availability in Ecosystems Balances between inputs, retention, & outflows Atmosphere dry deposition wet deposition Biology uptake fixation Cycling Precipitation Land use Soils geology weathering N, P, K, Ca, Mg Leaching Precipitation Land use soils and atmosphere are sources of nutrients availability varies with geology, climate, vegetation, land use human activity alters availability, acquisition, & leaching processes Biology 105 Module 3 3

4 Species Distributions The interaction between genotype & environment Sequoia sempervirens Redwood Highly sensitive to cold and dry conditions, limited to the western slopes of the coastal range in California Acer rubrum Red maple Highly tolerant of variable moisture, temperature, and soil conditions, found ubiquitously in the East distribution reflects patterns of resource availability best suited for the growth, survival, and reproduction of each species this combination of resources defines the species habitat Indicator Species Species that reflect the status of the environment indicator species reflect the health of the environment deformations, declines, behavioral changes reflect changes in environmental conditions Biology 105 Module 3 4

5 Amphibian Declines Loss of populations and species changes in the environmental conditions affect lifecycles (droughts) alteration of habitat limits ranges (development) species interactions may change with environment (parasites) global change factors exacerbate other factors Florida The Earth From Space 71% of the Earth is covered with water Columbia River, WA Texas coastal plain Pautuxent River, MD Marquette, MI Biology 105 Module 3 5

6 Aquatic, Wetland, & Coastal Systems Connections establish structure and function lakes streams wetlands weathering & erosion estuaries wetlands salt marshes deltas bays barrier island shoal reef bank upwelling 100 m 200 m photosynthetic zone continental margin continental shelf continental slope fresh and salt water systems vary in structure and function resource availability determines productivity resources derived from land and sea sources The Hydrologic Cycle precipitation infiltration & percolation transpiration surface runoff groundwater condensation evaporation water cycles through various pools in the environment cycling occurs when water changes state (liquid to vapor) this cycling is driven by solar energy Biology 105 Module 3 6

7 North American Biome Primary Productivity aquatic & ocean systems terrestrial systems high low high low ecosystem primary productivity exhibits distinct patterning, which reflects resource availability Energy Flow in Ecosystems Captured energy flows one-way through food web herbivores autotrophs carnivores heterotrophs decomposers ecosystems have two major biotic components { autotrophs heterotrophs autotrophs capture and transform solar energy this fixed energy is passed through a food web Biology 105 Module 3 7

8 Pyramid of Energy Flow Biomass or energy is ecosystem currency top carnivores carnivores herbivores producers decomposers energy flows from autotrophs (producers) to rest of ecosystem resource availability limits the complexity of the ecosystem Matter Cycles in Ecosystems Nutrients cycle through ecosystem compartments atmospheric pool autotrophs herbivores heterotrophs carnivores soil pools: organic matter inorganic nutrients decomposers the soil is the major pool for inorganic & organic matter autotrophs capture & fix nutrients (matter) heterotrophs rely on this productivity unlike energy, matter is cycled through a food web Biology 105 Module 3 8

9 Ecosystem Productivity Estimated net primary productivity in major biomes estuaries swamps & marshes tropical rain s temperate s taiga savannah agricultural lands temperate grassland lakes & streams open ocean tundra desert scrub NPP (kcal/m 2 /yr) ecosystems vary extensively in their energy & nutrient capture the most productive ecosystems are under the most pressure from human activity R 1 F 1 Ecosystem Models Lake ecosystem energy pools & pathways f- R 2 F 2 F 3 F 4 P 1 P 2 P 3 P 4 R = Resources F = Resource flow path P = Population size f = feedback (control over R, F, P) Biology 105 Module 3 9