Experimental transplants reveal strong environmental effects on the growth of non-vascular epiphytes in Afromontane Forests

Transplant studies can provide valuable information on the growth responses of epiphytic bryophytes and lichens to environmental factors. We studied the growth of six epiphyte species at three sites in moist Afromontane forests of Taita Hills, Kenya. With 558 pendant transplants we documented the growth of the selected four bryophytes and two lichens over the time course of one year. The transplants were placed into the lower canopy of one forest site in an upper montane zone and two forest sites in a lower montane zone. Several pendant moss species grew very well in the cool and humid environment of the upper montane forest, with some transplants more than doubling their biomass during the year. Conversely, all transplanted taxa performed poorly in the lower montane zone, presumably because of the unfavorable combination of ample moisture but excessive warmth and insufficient light which characterizes lower canopy habitats in dense lower montane forests. The results demonstrate that transplantation studies with pendant transplants can be used for monitoring growth of nonvascular epiphytes in tropical forests. The start weight of 0.25 g for pendant transplants worked well and can be recommended for future studies.