EAS 1540 Lecture Notes - Lecture 14: Pisaster, Seaweed, Kelp Forest

• School: Cornell University
• Department: Earth & Atmospheric Sciences
• Course: EAS 1540
• Professor: Bruce Monger

Document Summary

Zonation - organisms are in distinct layers a. b. Lower limit set by biological interactions (competition and predation) Species diversity within a rocky intertidal community a. b. Communities are divided into distinct bands/zones (lower intertidal, middle intertidal, upper intertidal) Species are not randomly distributed through intertidal zone, they are arranges within relatively narrow vertical ranges. Physical stresses set upper limit to species distribution (eg. heat, wave energy, food availability, salinity, oxygen, etc) Biological interactions set lower limit to species distribution. Physical disturbance can regulate species diversity within a community. Physical disturbance (waves) can open up gaps/patches in rocky intertidal. Intermediate disturbance hypothesis - disturbance maximizes species diversity by removing competitively dominant species and allowing less competitive species to reestablish themselves. Leads to higher species diversity within rocky intertidal community. Keystone species - species that have effects on their communities that are proportionately much greater than their abundance would suggest. Species that is determining diversity of rocky intertidal.