GERMINATION AND EARLY ESTABLISHMENT OF TILLANDSIA CIRCINNATA SCHLECHT. (BROMELIACEAE) ON SOME OF ITS HOSTS AND OTHER SUPPORTS IN SOUTHERN FLORIDA

Abstract

Epiphytes cast significant shade and cause limb breakage when they are present in great numbers in the crowns of host trees. These considerations aside, the classical notion persists among most botanists that vascular epiphytes are basically commensals with nonspecific host preferences and little negative impact on their supports. However, accounts have been accumulating at an increasing rate which suggest that some trees may, in fact, be adversely affected in a more systemic manner by their epiphytic associates (Cook, 1926; Went, 1940; Ruinen, 1953; Furman, 1959; Johansson, 1974, 1977; Benzing, Seemann & Renfrow, 1978). The authors of these reports
postUlate that, under some circumstances, heavily infested hosts may be forced into states of nutritional stress by the activities of their epiphytes. Conventional parasitism, epiparasitism and, most recently (Benzing & Seemann, 1978), stress-inducing degrees of nutritional piracy have been suggested as operative in the supposedly commensalistic epiphyte-host relationship. Attempts to describe the role epiphytes play in tropical forest ecology in a context of parasitism or within that of the biologically distinct but functionally equivalent phenomenon of nutritional piracy are motivated by the increasing realization that many trees harboring orchids or bromeliads experience reduced vigor as their infestations grow heavier.