These existing shrubs, weeds and grasses are typically pioneer or early succession species that compete fiercely for existing nutrient and water resources.
(These existing shrubs, weeds and grasses; are typically; pioneer or early succession species) (early succession species; compete fiercely; for existing nutrient and water resources)
These existing shrubs, weeds and grasses early succession species
are typically compete fiercely
pioneer or early succession species
for existing nutrient and water resources