Biology 3445F Lecture Notes - Lecture 20: Keystone Species, Primary Production, Intercropping

• School: Western University
• Department: Biology
• Course: Biology 3445F
• Professor: Zoe Lindo

Document Summary

Biodiversity: variability of living organisms (genetic, species, ecosystems, biodiversity loss leads to homogenisation at all ecological scales. Ecosystem function: cycling of materials, nutrients, energy; productivity, monocultures are the most productive systems in the world. Three bef hypotheses: a) species are primarily redundant: species are primarily singular, species impacts are context-dependent (aka idiosyncratic) (a) species are primarily redundant. Relationship is linear or single species are important (keystone: loss or addition of species detectable, species make unique contributions, positive linear relationship if all species matter, keystone species or ecosystem engineers (c) species impacts are context-dependent. Impact of loss or addition of species depends on environmental conditions: species make different contributions depending on conditions. Species are primarily redundant (3 groups of study = biomass production, nutrient uptake and decomposition: rivet hypothesis was most common. 3 ways to study bef: observations of diversity gradients, addition experiments (cedar creek, removal experiments.