Primary Productivity

1. Primary Productivity • Amount of energy or mass created during photosynthesis • gC/m2/yr or kcal/m2/yr • Net Primary Productivity: biomass for herbivores • GPP – CR = NPP • Factors that contribute to its success • Nutrients, temperature, sunlight, moisture

4. Primary Productivity • Factors that contribute to its success • Nutrients, temperature, sunlight, moisture • Nutrients as limiting factor • P = freshwater • N = terrestrial + marine

6. Ecosystems are stable, resilient, and resistant Stable: self perpetuating

7. Ecosystems are stable, resilient, and resistant • Resilient : repair itself • If a tree has been damaged it can regrow using suckers

8. Ecosystems are stable, resilient, and resistant • Resistant: ability to protect itself

9. Secondary Succession: soil is there.

10. Change is natural

11. Lichen are pioneer species Disturbances & the changes they bring about establish community characteristics Primary: No soil Secondary: starts with soiL MICROCLIMATE

12. Are major disturbances can be useful Yellowstone- 1988 • 700,000 aces burn for 2 months • Changed the structure of the ecosystem. • Stable ecosystems are resilient to change

13. Did the Yellowstone wildfire affect the abundance or diversity of organisms? How does the selective pressures Change? • Abundance of shade tolerant species decrease • Abundance of shade intolerant species increased • Diversity remained the same. • Disturbance adapted species: • Prairies • Deep roots • Forests • Serrotinous cones

14. Communities in Transition • Ecological Succession • Primary Succession - A community begins to develop on a site previously unoccupied by living organisms. Example: A lava flow creates a new land area that is colonized. The first colonists are termed pioneer species. • Secondary Succession - an existing community is disrupted and a new one subsequently develops at the site • Climax community - community that develops last and remains the longest

15. Disturbances • A disturbance is any force that disrupts established patterns of species diversity and abundance, community structure, or community properties e.g. storms, fires, logging. • Disturbance tends to disrupt the superior competitors the most and allows less competitive species to persist. • Some landscapes never reach a climax community because they are characterized by periodic disturbances (such as wildfires) and are made up of disturbance-adapted species.