Increasing liana abundance and biomass may have far-reaching consequences for tropical forest community composition, says Sanford.
For example, in a tropical moist forest on Barro Colorado Island, Panama, researchers found that the proportion of liana infestation in the crowns of trees changed from 32 percent in 1967-68 to 47 percent in 1979, to nearly 75 percent in 2007.
The number of trees with severe liana infestation (more than 75 percent of a tree's canopy covered by lianas) increased by 65 percent between 1996 and 2007.
In this forest, liana leaf litter and flower production, compared with that of host trees, increased substantially from 1986 to 2002, says Schnitzer.
Lianas have also overgrown other tropical forests.
In an old-growth forest surrounding the Nouragues Biological Research Station in French Guiana, scientists found that over the decade from 1992 to 2002, the number of lianas shot up while that of trees fell.
In a forest in the central Amazon, biologists discovered that over the six-year-period from 1993 to 1999, new liana seedlings were 500 percent higher than estimates from previous periods whereas tree seedling recruitment decreased.
But a tree need not live in the tropics to fall victim to lianas.
More than 80 non-native liana species have invaded North America.
Kudzu is joined by English ivy, Japanese honeysuckle and oriental bittersweet, to name a few. Oriental bittersweet is expanding in North American forests, where it has reduced native tree survival.
After hurricane damage in a Florida forest, invasive lianas rapidly colonized the damaged trees and persisted for many years afterward, reducing numbers of native trees, shrubs and herbs.
In 50-year-old forests in the Piedmont region of New Jersey, lianas are now abundant.
"A major factor limiting liana abundance in temperate fore
|Contact: Cheryl Dybas|
National Science Foundation