Liana - Ecology

Ecology

Lianas compete intensely with trees, greatly reducing tree growth and tree reproduction, greatly increasing tree mortality, preventing tree seedlings from establishing, and altering the course of regeneration in forests. Lianas also provide access routes in the forest canopy for many arboreal animals, including ants and many other invertebrates, lizards, rodents, sloths, monkeys, and lemurs. For example, in the Eastern rainforests of Madagascar, many prosimians achieve higher mobility from the web of lianas draped amongst the vertical tree species. Many lemurs prefer trees with lianas for their roost sites. Lianas also provide support for trees when strong winds blow. However, they may be destructive in that when one tree falls, the connections made by the lianas may cause many other trees to fall.

As noted by Charles Darwin, because lianas are supported by other plants, they may conserve resources that other plants must allocate to the development of structure and use them instead for growth and reproduction. In general, lianas are detrimental to the trees that support them: growth rates are lower for trees with lianas, they directly damage hosts by mechanical abrasion and strangulation, render hosts more susceptible to ice and wind damage, and increase the probability that the host tree falls. Lianas also make the canopy of trees more accessible to animals which eat leaves. Because of these negative effects, trees which remain free of lianas are at an advantage; some species have evolved characteristics which help them avoid or shed lianas.