REN R322 Lecture Notes - Lecture 16: Ericaceae, Germination, Lichen
24 Oct 2016
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Commensalism: epiphytes, provision of habitat, primary cavity nesters. Competition: between organisms for limiting resources: e. g. plants for light, water nutrients; animals for food, nesting or shelter sites, mates. Competition: individuals of the same (intra-speci c) or different (inter-speci c) species, using the same resource which is (potentially) in limited supply, both partners are negatively affected (energy cost, scramble competition: soil water, nutrients, interference competition: light. Competition for light: moderating in uence of below-ground competition. Herbivory: most often species-speci c, reduce growth, cause mortality, moderates competitive interactions. Allelopathy: chemicals released by one plant negatively affect another: root exudates, decomposition. Microbes: take up atmospheric nitrogen (n2 gas) make it available to other organisms. E. g. microbes in root modules of legume plants (the pea family includes lupines) Lobar oregano - n2 xing, epiphytic lichen: wind river canopy crane: 1. 5 kg n/ha/yr, h. j. Nostoc cyanobacteria within leaf axils of the moss pleurozium schreberi (big red stem)
