2.27.97
Weedy Life Cycles
feedback.html
Feedback from Developing vegetation and its Influenceon the
Recruitment of Seedlings
Presence of vegetation profoundly influences subsequent recruitment of seedlings
from the soil seedbank (the environmental sieve)
Order and organization of plant communities appear in populations because
of feedback from existing populations on new recruits
Recruit seedlings themselves interact: presence of vegetation profoundly
influences the environmental sieve
Almost all the feedback from existing vegetation on seeds is to inhibit
further seedling recruitment
Developing vegetation causes major changes in the environment at and beneath
the soil surface:
-shading decreases quantity and changes quality of light and affects light
regulated germination
-crop canopy alters rate of water loss, slowing loss and creating better
temperature and humidity conditions on surface
-falling leaves and vegetation, and later decomposition products, alter
chemical and physical surface qualities, cover seeds
-rising carbon dioxide levels in soil due to root respiration and litter
decomposition can reduce the number of seedlings germinating
-allelopathic compounds (toxins) from vegetation can inhibit germination
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