Experience of a Synthetic Approach to an Ecological Classification of Vascular Epiphytes

Abstract

On the basis of an investigation into epiphytic ferns and taking into account the literature data, information on ecological classifications of vascular epiphytes has been summarized and a multiple ecological classification is proposed in which vascular epiphytes are grouped into three blocks of morphofunctional types (MFT): facultative epiphytes (protoepiphytes), obligate epiphytes (holoepiphytes), and hemiepiphytes. The main criterion underlying this division is the degree of specialization of plants to the epiphytic life pattern. Each group includes several subgroups diverging on the basis of the presence of special morphological structures providing epiphytes with nutrients and water under conditions of their deficit, as well as life under the conditions of low irradiation and high hydrature. Within the subgroups, the variants are distinguished and the preadaptive and adaptive mechanisms used by the epiphytes in order to cope with the specific environment are defined for the variants. Physiofunctional types with specialization to an epiphytic mode of life are distinguished as well.