REWM 3500Rangeland Plant EcophysiologyMonday, November 9, 2009
Plant-plant interactions
Facilitation and Competition
Models of resource competition
Can plants sense presence of neighbors?
What traits confer competitive success in arid and semiarid rangeland?
Interference competition (Allelopathy)
responsesp-A sp-B
Neutral 0 0Mutualism + +Commensalism + 0Amensalism - 0Parasitism + -Herbivory + -Predation + -Competition - -
Biotic interactions
Facilitation of Agave by Hilaria
Facilitation of neighboring plants
Hydraulic lift in Artemisia improves growth of neighbor plants
Facilitation of neighboring plants
Tilman (1988) model of resource competition
Direct evidence of resource competition
Can plants sense presence of other plants?
Mahall and Callaway 1991
Root-root communication and interference
Ambrosia roots growing into Larrea roots
Larrea roots growing into Ambrosia roots
Mahall and Callaway 1991
Root-root communication and interference
Allelopathic compound released to soil may account for root-root interference
Allelopathic compound leached from leaves of black walnut (Juglans niger)
Bais et al. (2003) - Allelopathy in spotted knapweed (Centaurea maculosa)
Terms and concepts to know:
facilitationparasitismneutral interactions competition nurse plantresource competitioninterference competition (Allelopathy)relative growth rateGrime and Tilman models of competitionR/FR light ratios