Elements of disturbance that affect epiphyte vitality in a temperate rainforest:an experimental approach  

作　　者：Nalini M.Nadkarni Kevin D.Kohl 

机构地区：[1]Department of Biology,University of Utah,257 South 1400 East,Salt Lake City,UT 84112,USA [2]Department of Biological Sciences,University of Pittsburgh,403B Clapp Hall,4249 Fifth Avenue,Pittsburgh,PA 115260,USA

出　　处：《Journal of Plant Ecology》2019年第2期306-313,共8页植物生态学报（英文版）

基　　金：National Science Foundation(EHR 15-14494 and DEB 11-41833 to N.M.N.and DBI 1400456 to K.D.K.).

摘　　要：Aims Epiphytes are an abundant and diverse component of many wet temperate forests and have significant roles in ecosystem processes.Little is known about the processes and rates of their death and decomposition when they fall from the canopy,which limits our understanding of their role in forest carbon sequestration and nutri-ent cycling.In the temperate rainforest of the Quinault River Valley,Washington State,our aim was to test hypotheses regarding four elements of disturbance that might contribute to their decline.Methods We established set of experiments in which we placed samples of canopy epiphytes and their branch segments:(i)in the canopy versus forest floor microenvironment(stratum);(ii)attached to live versus dead branch substrates;(iii)subjected to physical disruption and‘jarring’;and(iv)in direct versus indirect con-tact with the forest floor.Over the 2-year study,we assigned a non-destructive‘vitality index’(based on color and appar-ent mortality and dryness)to each sample every 2-3 months to compare effects of the experimental treatments and analyzed with a statistical model and post hoc pairwise comparisons of treatments.Important Findings The canopy versus ground stratum and live/dead branch status sig-nificantly affected epiphyte vitality.Effects of physical disruption and ground contact were not significant.There were seasonal effects(low vitality during the sampling times in the summer,revitalization upon sampling times in the winter)for all treatments except samples in contact with the ground.One implication of these results relates to effects of climate change,which is predicted to shift to hotter,drier summers and wetter winters.Climate change may affect forest dynamics and nutrient cycling in unpredictable ways.Results also point to future experiments to understand biotic and abiotic effects on epiphyte disturbance and dynamics.

关 键 词：DISTURBANCE EPIPHYTES forest canopy forest dynamics MOSS Olympic rainforest 

分 类 号：S71[农业科学—林学]