The epiphyte vegetation of the palm Socratea exorrhiza - correlations with tree size, tree age and bryophyte cover

Abstract

Abstract:We conducted a survey of the epiphyte flora growing on the stilt palm Socratea exorrhiza in a primary lowland rain forest in Panama by means of a canopy crane. For each palm in a 0.9-ha plot, we determined diameter at breast height, tree height, per cent bryophyte cover and the number, identity and attachment site of all vascular epiphytes. The 118 palm trees hosted a total of 701 epiphytes and hemi-epiphytes, belonging to 66 species. Trees were estimated to be c. 20 y old before colonization with vascular epiphytes began. Epiphyte species were highly clumped and segregated along the vertical axis of the trunk. Sequential colonization led to an increased number of species and individuals as the tree grows. Epiphytes were associated with bryophyte patches much more than expected by chance, but no species seemed to depend upon them for establishment. The influence of tree size, age and bryophyte cover on the composition of the epiphyte community are discussed.

Diversidade de bromélias epífitas na Reserva Particular do Patrimônio Natural Serra do Teimoso - Jussari, BA

“…Esta hipótese é baseada em trabalhos realizados em escala local, que mostraram que algumas espécies arbóreas são desproporcionalmente propícias ao epifitismo (Waechter 1980, Benzing 1990), que C. legalis ocorre desde o estado de Pernambuco até o estado de São Paulo, sendo uma espécie característica do dossel, com grandes diâmetros (Sebben et al 2000). Uma vez que a Floresta Atlântica é um bioma predominantemente úmido e que árvores com grandes diâmetros são, em sua maioria, forófitos de epífitas (Migenis & Ackerman 1993, Zotz & Vollrath 2003, Alves 2005) é provável que esta hipótese seja verdadeira.…”

“…de 5 cm) e mais freqüentemente em árvores que possuem diâ-metros acima de 10 cm. A maior freqüência de epífitas em árvores com grandes diâmetros aparentemente não é uma exclusividade das bromélias das matas higrófilas sul baianas, mas ocorre de maneira geral em outras áreas de florestas tropicais (Migenis & Ackerman 1993, Zotz & Vollrath 2003. Além deste padrão de ocupação das árvores, levantamentos realizados nas florestas do Panamá (Nieder et al 2001), México, Bolívia e Venezuela têm indicado que a área necessária para amostrar a maioria das espécies epífitas a ocorrer em uma região é relativamente pequena se comparada à área necessária para amostrar a maioria das espécies de plantas terrestres (Nieder et al 1999, Gradstein et al 2003.…”

Habitat utilization and CAM occurrence among epiphytic bromeliads in a dry forest from southeastern Brazil

“…Phorophytes of general epiphytes have larger sizes than trees that do not host these plants, a pattern already reported for forested areas in Bahia (Alves 1990, Alves 2005, Ecuador (Dunn 2000), and Central America (Zotz & Vollrath 2003). One of the factors that may contribute toward this pattern is that large trees have been there longer, as usually the largest trees are also the oldest, being easier targets to be reached by seeds (Bennett 1987).…”

“…This is probably the case with the epiphytic fl ora in the Jacarepiá dry forest, with an annual rainfall below 1000 mm (Sá 1992). Comparatively, rainfall in Jacarepiá is more similar to the dry forests from Ecuador (800 mm y -1 ) than to other Atlantic forests located in Panama or Brazil (Fischer & Araújo 1995, Zotz et al 1999, Zotz & Vollrath 2003, Borgo & Silva 2003, Gonçalves & Waechter 2003, with annual precipitations above 1,600 mm.…”

“…In this regard, although it is biologically reasonable to assume that large trees have higher abundance and richness of epiphytes, correlations between diameter and abundance are by no means the rule (see Ingram & Nadkarni 1993, Moran et al 2003. Some authors have suggested that correlations may occur because of longer exposition of the trunks to epiphytic seeds (Bennet 1987), while other authors have stated that the lack of correlation may occur due to environmental conditions, such as microclimatic variations, or accidents caused by foraging arboreal animals (Perry 1978, Zotz & Vollrath 2003. Besides the infl uence of tree diameter, the microsites available on large trees are important for the vertical zonation of epiphytes, especially in humid forests (Johansson 1974) where epiphytes are more abundant and rich on the primary ramifi cations of phorophytes.…”