Modeling and mapping distributions of common bryophytes across New Brunswick using a lidar-derived depth-to-water index

Abstract

Plant species distribution is known to vary along environmental gradients. This project uses a cartographic depth-to-water (DTW) index to model the potential distributions of six common mosses and one leafy liverwort in New Brunswick at a landscape scale. Species composition and relative abundance of bryophytes were measured along transects traversing the landscape, from wetlands to uplands. Frequency of occurrence patterns were quantified using regression models. Species were found to sort along the moisture gradient; Bazzania trilobata, Dicranum polysetum, Polytrichum commune, Hylocomium splendens, and Pleurozium schreberi had greater probabilities of occurrence in well-drained forested areas, whereas hydrophytic mosses such as Sphagnum fuscum and Sphagnum girgensohnii were predominantly in low lying wet areas. The results support the prediction that wetness-related changes in distributions of bryophytes can be modeled using the depth-to-water index in combination with other environmental variables such as forest type. This research contributes to existing knowledge regarding bryophyte species’ responses to environmental factors.