Plant competition?

Question

Do plants always compete with plants of a different species? How would competition be different between plants of the same species?

Answer 1

Plants within a species compete, too - survival of the fittest. For plants, that might be the ability to dig deeper or firmer roots, or to grow higher than other members of your species to get above the shrubs for sunlight.

Different species may not be competing for the same niche. Members of the same species are.

Answer 2

Intraspecific competition, or competition within a species, is how natural selection acts. Every population has a range of traits. As the environment changes one portion of the species will have traits more suited to those new conditions possibly allowing them an increase in offspring and a greater representation of those alleles in future generations. Plants compete less directly than animals. They do not have males fighting to keep harems from younger males but they do fight to pollinate more flowers in their own way. The plant that puts out a better scent for pollen foraging beetles will receive more visits so may have more pollen delivered to more pistils than another plant in the same species.

Competition for Pollinator Service: A Stimulus for the Evolution of Autogamy

http://www.nature.com/hdy/journal/v56/n2...

http://www.sciencedirect.com/science?_ob...

Interspecies competition, refers to how species compete for resources like sunlight or root space. Plants compete for sunlight so they may partition the canopy space or adapt to different levels of light exposure.  Understory plants use low light level and avoid exposure to strong storms by sheltering under larger plants. They also avoid high UV damage so have fewer expensive repair mechanisms. There are always trade offs in avoiding competition by coexisting. This is another way selection acts by shifting the environment. As each species adapts it forces all other species to also change. This is the Red Queen Theorem. Each species must change as fast as possible just to hold its place.

http://www.springerlink.com/content/v538...

http://privatewww.essex.ac.uk/~scher/My%...

http://www.blackwell-synergy.com/doi/abs...