Primary Productivity  Amount of energy or mass created during photosynthesis  gC/m 2 /yr or kcal/m 2 /yr  Net Primary Productivity: biomass for herbivores  GPP – CR = NPP  Factors that contribute to its success  Nutrients, temperature, sunlight, moisture

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

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

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

Ecosystems are stable, resilient, and resistant  Resistant: ability to protect itself

Secondary Succession: soil is there.

Change is natural

PRIMARY: NO SOIL SECONDARY: STARTS WITH SOIL MICROCLIMATE Lichen are pioneer species

YELLOWSTONE  700,000 aces burn for 2 months  Changed the structure of the ecosystem.  Stable ecosystems are resilient to change

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

 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

 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.