Week 10: Community, Ecosystem, and Global Ecology

Competition Intraspecific competition = within species Interspecific competition = between species Two possible outcomes Niche differentiation, coexistence 2) Competitive exclusion

Disturbance and Succession Primary succession: when a disturbance removes soil and its organisms as well as organisms that live above the surface. Caused by: glaciers, floods, volcanic eruptions, and landslides Secondary succession: when a disturbance removes some or all of the organisms from an area but leave soil intact. Caused by: fire and logging

Disturbance and Succession Patterns affected by: The particular traits of a species involved Dispersal ability Tolerance to harsh abiotic conditions Reproductive rate How the species interact Facilitation Tolerance Inhibition Historical and environmental circumstances Size of burn patch Weather conditions

Trophic cascade Top down control

Productivity NPP = GPP - R Limited by any factor that limits photosynthesis Terrestrial: highest near equator Marine: highest near coastlines Productivity

Threats to biodiversity Habitat destruction Habitat fragmentation Edge effect Small, isolated populations Overexploitation Invasive species Pollution Climate change

Biodiversity Significance More productive Resource use efficiency – niche differentiation facilitation More resistant to disturbances and invasions More resilient More ecosystem services Artemisia annua Antimalarial drug

Preserving Biodiversity Sustainability: the managed use of resources at a rate only as fast as the rate at which they are replaced Genetic restoration Wildlife corridors Protected areas Accounting for ecosystem services in public policy