Browsing (herbivory)

Browsing is a type of herbivory in which a herbivore (or, more narrowly defined, a folivore) feeds on leaves, soft shoots, or fruits of high-growing, generally woody plants such as shrubs.

[7] Overbrowsing occurs when overpopulated or densely-concentrated herbivores exert extreme pressure on plants, reducing the carrying capacity and altering the ecological functions of their habitat.

[8][9][10] Examples of overbrowsing herbivores around the world include koalas in Southern Australia, introduced mammals in New Zealand, and cervids in forests of North America and Europe.

[14] Compositional and structural changes in forest vegetation can have cascading effects on the entire ecosystem, including impacts on soil quality and stability, micro- and macro- invertebrates, small mammals, songbirds, and perhaps even large predators.

[16] Also, landscape changes due to human development, such as in agriculture and forestry, can produce fragmented forest patches between which deer travel, browsing in early successional habitat at the periphery.

[17] Agricultural fields and young silvicultural stands provide deer with high quality food leading to overabundance and increased browsing pressure on forest understory plants.

The negative effects of browsing are greater among intolerant species, such as members of the genus Trillium, which have all photosynthetic tissues and reproductive organs at the apex of a singular stem.

[22][23][24] Overbrowsing can change near-ground forest structure, plant species composition, vegetation density, and leaf litter, with consequences for other forest-dwelling animals.

[27] Refugia in the form of windthrow mounds, rocky outcrops, or horizontal logs elevated above the forest floor can provide plants with substrate protected from browsing by cervids.