Theory 32/Grassland & Savanna/Shrub encroachment
Encroachment Follows Grazing
The claim
Shrub encroachment occurs above a threshold in grazing removal, because grass competition is what keeps shrubs from establishing.
01Mechanism
Grasses compete for water in the surface layers; when grazing reduces them, shrubs escape the competitive filter.
02Prediction
Encroachment should track grazing pressure.
03Refutation
Encroachment tracking rainfall would remove competition.