CompetitionDisturbance2011

CompetitionDisturbance2011 - 9/2/2011 Ecological Principles...

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Unformatted text preview: 9/2/2011 Ecological Principles 2: Competition and Disturbance Ecological Community Species that interact within a given habitat Biology of corals How do so many species coexist? Competition and succession Intermediate disturbance hypothesis Most diverse 32 Phyla Coral Reefs Most complex Symbiosis, competition, predation Most productive 200 g C m-2 y-1 Chlorophyll Oldest 400 million yr. fossil record 1 9/2/2011 Symbiotic algae: Zooxanthellae Cnidarians "Fix" Carbon : Carbohydrates, Sugars Cnidos = "stinging needle" Nematocyst "Harpoons" Symbiotic algae 2 9/2/2011 Photosynthesis [ O2 ] Respiration Video 1: NG : Photosynthesis and coral reefs Time CO2 + H2O Plant Plant Plant C6H12O6 + O2 Animal O2 Sugars O2 The Nature of Coral Symbiosis Algae Produces / Coral Needs Coral Produces / Algae Needs A perfect CO2 Animal balance of production N & P Animal and consumption CO2 Nitrogen "waste" Phosphorous "waste" Limestone (Calcium) "Tree trunk" Starches Amino Acids Photosynthesis 3 9/2/2011 Hi Common corals were getting commoner. Rare corals were getting rarer ! Lo Rare Common 4 9/2/2011 Ecological succession Directional and continuous patterns of species turnover at a site Temporal change in species composition Succession and competition Competition: when two or more individuals attempt to use the same resource Competition is a dominant force structuring ecological communities! Video 2: Hurricane Allen, 1980 5 9/2/2011 Hi Lo Rare Common Disturbance: storms, fires, tornados, floods, drought, volcano Intermediate Disturbance Hypothesis High Can `reset' the stage for ecological competition Low Low Intermediate Frequency of Disturbance High 6 9/2/2011 Intermediate Disturbance Hypothesis Diversity is maintained if : Natural disturbances Physical Factors Selectively remove the commonest species (best competitors) Coral Abundance Discovery Bay, Jamaica Surface Area ( cm2/10 m2 ) and Colony Occurrence ( #/10 m2 ) Species Acropora palmata Agaricia agaricites Montastrea annularis Porites astreoides 1980 12,033 ( 59 ) 1,337 ( 56 ) 278 ( 2 ) 326 ( 12 ) 1981 1,419 ( 6 ) 429 ( 24 ) 289 ( 2 ) 112 ( 4 ) 1982 1,413 ( 4 ) 429 ( 24 ) 217 ( 2 ) 112 ( 4 ) Coral Abundance Discovery Bay, Jamaica Surface Area ( cm2/10m2 ) and Colony Occurrence ( #/10m2 ) Long-term Change on Jamaican Coral Reefs Date Ecosystem Control Biological : Competition Physical : Hurricane Biological : Predation Causative Agent Natural Natural Natural Species Acropora palmata 1980 12,033 ( 59 ) 1,337 ( 56 ) 278 ( 2 ) 326 ( 12 ) 1981 1,419 ( 6 ) 429 ( 24 ) 289 ( 2 ) 112 ( 4 ) 1982 1,413 ( 4 ) 429 ( 24 ) 217 ( 2 ) 112 ( 4 ) 1983 1900 - 1980 3,820 ( 21 ) 1980 631 ( 29 ) 1980 - 1983 291 ( 5 ) 201 ( 6 ) Agaricia agaricites Montastrea annularis Porites astreoides Dominant ecological forces can change over time 7 9/2/2011 Coral Loss in Jamaica Hurricane Allen Recovery ? Sea Urchin Loss Followed the Currents 8 9/2/2011 Coral Loss in Jamaica Hurricane Allen Sea urchin die-off Nutrient addition Video 3: HBOI: Jamaican coral reefs, 1999 Long-term Change on Jamaican Coral Reefs Date 1900 - 1980 1980 1980 - 1983 1983 - 1990 1990 - 2000 Ecosystem Control Biological : Competition Physical : Hurricane Biological : Predation Biological: Grazer Removal Physical : Nutrient Addition Causative Agent Natural Natural Natural Introduced Pathogen? Anthropogenic ( Human ) Video 4: Australia Barrier Reef Long-term Change on Jamaican Coral Reefs 1. The ecosystem was resilient to one stressor ( hurricane), but not multiple stressors. 2. Chronic stress ( pollution ) is worse than short-term stress ( the hurricane ). 3. Anthropogenic stress is worse than natural stress. 4. Increasingly, human interference controls this ecosystem. 9 ...
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This note was uploaded on 10/04/2011 for the course ECOL 1000 taught by Professor Altizer during the Fall '08 term at University of Georgia Athens.

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