Invertebrate communities of subcanopy epiphyte mats subject to commercial moss harvest

Subcanopy epiphytic bryophyte mats are subject to the commercial removal of over 3.7 million kg/year of fresh epiphytic bryophytes (the non-timber forest product of “moss”) from the Coast and Cascade Mountain ranges in the Pacific Northwest of North America. This paper reports on four pilot studies that provide the first characterization of the invertebrates impacted by this harvest. Invertebrates were extracted from harvestable moss mats in both mountain ranges over a period of 4 years. A total of 205 morphospecies and over 143,000 individuals were found in 337 moss mats (totaling less than 25 kg of moss, fresh weight). Invertebrates associated with both canopy and forest floor habitats were recorded. Overall morphospecies composition did not differ between mats harvested from the shrubs vine maple ( Acer circinatum ) and huckleberry ( Vaccinium parvifolium ), nor between mats harvested from the stem bases and the branch tips of vine maple. The invertebrate fauna composition was correlated with elevation, stand age, and the vertical distance to water in both the Coast and Cascade Mountain ranges. The lack of differentiation in morphospecies with mat position or host species indicates that these commercial moss harvest practices do not discriminate among taxa, but the overall impacts of harvesting have yet to be determined.