Effects of animals on vegetation

In several agroforestry systems, animals are an important component. Animals graze and affect the grasslands and fodder trees considerably. The effect of animals on vegetation includes direct harmful and beneficial effects, which are described below:

Harmful effects

Grazing animals directly affects on vegetation by mechanical damage and browsing of young plants and regeneration, reduction in combustible materials such as fire wood, twigs, leaf litter due to the mechanical damage by grazing animals, and indirectly affects on regeneration, and effect on soil properties (soil compaction which results on reduction in pore space that means disturbance in aeration, infiltration and permeability), which affects on tree growth. These effects are very much related to the number of grazing animals to be grazed within the carrying capacity of the land, quantity of grass and fodder, grazing season, grazing frequency etc.

Over grazing can also result on soil erosion and land degradation, which will have negative effects on vegetation.

Beneficial effects

• Grazing animals help in seed dispersal by adhering to them or by being eaten by them.
• Add organic matter into soil by breaking down and mixing of leaf litter into the soil, and by urine and dung of grazing animals.
• Reduce fire hazard by reducing the amount of burning materials.