Unformatted text preview: fecting species richness Why do species diversity and genetic diversity
respond in opposite directions? How does fertilization affect genetic diversity?
-Trend is not dramatic, but it is real
-Adding more nutrients = more (+) genetic
diversity • Fertilizer eliminates a limiting resource of a
competitively dominant species
• Competitive dominants Measured w. molecular markers eliminate ‘weaker’ species • Elimination of ‘weaker’ competitors opens ‘niche
space’ for more genotypes of the remaining species
• Genotypes of A. odoratum: more dimensions of N, P, K,
and Mg to specialize on when fewer species are present For a focal species, Anthoxanthum odoratum
Silvertown et al. 2009, Ecology Letters 12: 165 170 28 Silvertown et al. 2009, Ecology Letters 12: 165 170 29 30 -Adding the resource: Limiting resources prevent 1 species from crowding out everyone out.
Adding more N allows this one species to crowd everything out, if only it had more N. Adding
more K allows another species to out compete etc. etc.
-As these dominant species are having their ABIOTIC LIMITS REMOVED, they out-compete
weaker species (------ species diversity)
-When weaker species are out-competed, this means that there is more NICHE space PER
G ENOTYPE of the remaining species (+++++++ genotype diversity) 5 -There are more resources available to be allocated to the thriving of weaker genotypes
-There are more resources that the weaker genotypes can specialize on, once we have eliminated weaker species 19/03/2013 Summary: Ecological consequences of genetic
• Ecology Selection
• Genetic variation in focal species Ecology Evolution evolutionary response Newer View
Ideas above PLUS: -Genetic variation affects ecological processes
• Genetic variation in focal species ecological processes
• Genetic variation within species will affect almost all ecological
Genomics – Distribution and abundance of other species
– Disturbance recovery
– Nutrient decomposition Bio 220 lives here 31 32 -"Look for parallels bet ween genetic/species diversity with Tilman example"
-Compare this to areas where we are harvesting key individuals (e.g. in corn)
-Where can we draw parallels bet ween these lectures? 6...
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