There is still no consensus as to why lianas are gaining the upper hand. They may survive seasonal droughts that are becoming more common as climate becomes more variable. They may recover more quickly from natural disturbances such as hurricanes and El Nio events and from human disturbances like logging, clearing land for agriculture and road building. Lianas respond quickly to an increase in atmospheric carbon dioxidegrowing faster than associated tree species in several experiments.
In North American forests, invasive vines such as kudzu, oriental bittersweet, English ivy and Japanese honeysuckle often reduce native tree regeneration and survival, although there is no obvious trend as there is in the American tropics. In contrast, two studies of forests in tropical Africa did not detect vine overgrowth.
To understand the nature of this contemporary spell that has been cast on the tropical forests of the Americas, the authors propose to take advantage of the widespread network of large-scale, long-term monitoring plotsthe Smithsonian Institution Global Earth Observatory network coordinated by the Center for Tropical Forest Sciencecombined with experiments to reveal what gives vines a competitive edge over trees.
Business models for investment in climate-mitigation schemes through carbon storage, climate models and water availability all rely upon accurate information about tree growth and cover in tropical forests. The major physical transformations indicated by this research call the reliability of such models into question.
|Contact: Beth King|
Smithsonian Tropical Research Institute