The Natural History of Lianas on Barro Colorado Island, Panama

Abstract

Liana (woody vine) abundance, height, diameter, and climbing mode were studied in the mature tropical moist forest on Barro Colorado Island, Panama (BCI). Because lianas are capable of extended horizontal as well as vertical growth, sample plots were 100—m2 cylinders extending from the ground up to the treetops. The plots were randomly located in areas representing different stages of regeneration following treefalls. In order to examine canopy lianas closely, trees in or adjacent to the sample plots were climbed freehand or with the aid of mechanical rope ascenders. Lianas are abundant on BCI and play important roles in forest dynamics. A hectare of old—growth forest had 1597 climbing lianas distributed among 43% of the canopy trees. Trees with a least one liana has higher than random probability of having more than one liana, and individual lianas connected an average of 1.56 canopy trees. In the understory, 22% of the upright plants <2 m tall were lianas, and, depending on the species, between 15 and 90% of these plants were vegetative offshoots (ramets) and not true seedlings (genets). Lianas were most abundant in recent treefall gaps and decreased in abundance with time since last disturbance. Trellis availability was found to be a major factor limiting liana access to the forest canopy. Experimental manipulation of supports and experimental planting of Dioclea reflexa seedlings revealed that trellises consisting of small diameter, closely spaced supports are most abundant on the edges of treefall gaps. Tree and liana stems on the edges of treefall gaps provided a major pathway to the canopy for climbing plants. Trees carrying lianas suffered higher mortality rates and upon falling caused more other trees to fall than did liana—free trees. Few lianas died when their host tree fell, and many grew back to the canopy using the abundant trellises that occur on the edges of treefall gaps. Tree sapling growth rates in treefall gaps and Luehea seemannii growth rates in the canopy were slower where lianas were abundant.

Estrutura fitossociológica da comunidade de lianas em uma floresta estacional semidecidual na Fazenda Canchim, São Carlos, SP

“…A diversidade de lianas em florestas tropicais é um dos principais itens abordados ao se estudar a Flora Neotropical (Putz 1984, Gentry 1991. O índice de diversidade de Shannon (H'), estimado para as espécies de lianas amostradas neste estudo foi de 3,20 nats.…”

“…As lianas são componentes estruturais importantes e representam parte significativa da flora de florestas tropicais (Putz 1984, Gentry 1982. Nas florestas estacionais semidecíduas do Estado de São Paulo, que sofreram diferentes formas de perturbações e que atualmente encontram-se restritas a pequenos fragmentos (Leitão Filho 1987), as lianas tornaram-se muitas vezes abundantes, podendo, até mesmo, interferir na dinâmica natural destas florestas, muito embora sua presença seja mais benéfica que prejudicial (Morellato & Leitão Filho 1996;Engel et al 1998).…”

“…As lianas, que apresentam rápido crescimento comparado com as espécies arbóreas (Putz 1984), chegam a dominar as copas das árvores suportes e das árvores vizinhas. Para o estudo da dinâmica e manejo florestal, é fundamental o conhecimento deste grupo de vegetais, devido à sua diversidade e importância ecológica (Putz 1984).…”

“…Para o estudo da dinâmica e manejo florestal, é fundamental o conhecimento deste grupo de vegetais, devido à sua diversidade e importância ecológica (Putz 1984).…”

Mortality and diameter growth of lianas in a semideciduous forest fragment in Southeastern Brazil

“…Dense groupings of one species were considered as only one individual, these probably being rooted ramets left, after the fall of the originalliana or its canopy support (Putz 1984). Stem diameters were measured at the same point every six months with the use of calipers; only the lianas alive after the 30-month period of study were counted for diameter growth rate ca1culations.…”