Gefässepiphyten in temperaten Wäldern

Abstract

Vascular epiphytes are most abundant in the humid tropics with a large amount of ecological information accumulating in recent decades. Surprisingly, there is very little quantitative information on the ecology of temperate taxa. This paper summarizes the existing information on epiphytism in the temperate zone, discusses hypotheses on the abiotic conditions limiting epiphytism in non-tropical regions, and reports first results of a pilot study on epiphytic Polypodium vulgare L. (Polypodiaceae) in a montane forest in Central Switzerland. It is concluded that this fern can be locally abundant in temperate forests, but its occurrence is restricted to particular microsites within the canopy of particular tree species. The exact mechanism constraining vascular epiphytes in the temperate zone still awaits experimental analysis.