2. Basic Ecology

3. Study of the interactions among ecosystem residents and their environment Residents… …individuals …populations …communities Ecology – the basics Niche… …the role or function of a population within its ecosystem

4. Study of the interactions among ecosystem residents and their environment Ecology – the basics Abiotic components… …air …water …soil …temperature Habitat… …the local environment of a population, biotic and abiotic

5. Fundamental concerns: …flows through ecosystems; not recycled Ecology – the basics Fixed by producers, harvested by consumers & detritivores Used for respiration, tissue maintenance & reproduction Some is lost with each transformation Transformed, stored and transferred

6. The trophic pyramid of a terrestrial ecosystem 1-10% energy transformation efficiencies

7. Fundamental concerns: Ecology – the basics …cycles within ecosystems. Assembled by producers, harvested by consumers, reused by producers

8. Reservoirs: GT Transfers: GT/yr

9. Compartments: GT Transfers: GT/yr Compartments: MT Transfers: MT/yr

10. Compartments: MT Transfers: MT/yr

11. A Food Web (Trophic Web) illustrates energy and nutrient transactions in an ecosystem

12. Ecosystems are dependent on their primary producers soil nutrients Limits to Primary Production Light Water Nutrients Temperature On land, the most favorable combination of these assets is found in tropical rainforests !!Tropical rainforest litter residence time is very low!! Essentially free resources

13. The effect of climate on organic decomposition temperate forest floortropical rainforest floor over comparable time periods

14. GPP – R = NPP Gross Primary Production – Respiration = Net Primary Production

15. NPP is higher in tropical rainforests than other forest ecosystems

16. Energy Budget Energy available for consumer trophic levels depends on… …NPP*efficiency of transfer(s) (5-20%)* assimilation efficiency(ies) = assimilated/ingested …depends on type of ingested material e.g. wood: 15%; seeds/animal tissues: 90%

17. Energy Budget Consumer production… =assimilated energy – respiration – excretion Net Production Efficiency = production/assimilation …depends on the animal bird: 1%; sedentary cold-blooded: 75%

18. O (organic) Horizon A Horizon Zone of Leaching B Horizon Zone of Accumulation C Horizon Partially decomposed parent material Soils develop from above and below organic mineral provide primary producers with… …water …mineral nutrients …anchorage Soils

19. Soil Texture Classification Soil particle size classes <0.002 mm clay 0.002-0.05 mm silt 0.05-2 mm sand % clay % silt % sand

20. Some Soil Properties Influenced by Soil Texture Texture Class Soil PropertySandSilt LoamClay Aerationexcellentgoodpoor Drainageexcellentgoodpoor Tillageeasymoderatedifficult Spring Warmingrapidmoderateslow Water holdinglowmoderatehigh Cation Exchangelowmoderatehigh

21. Soil Weathering in Tropical Rainforests Laterization – wet warm climates – clay particles broken down – silica leached downward – iron & aluminum oxides retained – low nutrient holding capacity – low organic content