Acta Univ Latv (2006) 710: 103–116

Epiphytic bryophytes in old growth forests of slopes, screes and ravines in north-west Latvia

Abstract

Little is known about the ecology of epiphytic bryophytes in broad-leaved forests of slopes, screes and ravines. Factors determining the epiphytic bryophyte distribution in such forests were investigated. In total 45 epiphytic bryophyte species were found (12 of them were signal species, including three specially protected species in Latvia – Antitrichia curtipendula, Neckera crispa and Plagiothecium latebricola). The total number of bryophyte and number of signal species were higher on tree species with relatively basic bark pH (Acer platanoides, Ulmus glabra, Fraxinus excelsior, Populus tremula, Sorbus aucuparia, Tilia cordata, Salix sp.), but lower on tree species with acidic bark (Alnus glutinosa, Betula pendula, Picea abies). Tree diameter, age and distance from tree to top of slope were not related to epiphytic bryophyte distribution. The highest bryophyte species richness (including signal species) was found up to a 0.5-m height on the southern exposure of trees and on the upper side of inclined trees (on south exposure of trees on north facing slopes, and on east exposure of trees – on west facing slopes).