Road fragmentation in forested peatlands
Photo: Caitlin Willier
A forested wetland bisected by a road, with oobservable hydrological and vegetation changes on both sides.
Evaluating differences in plant community composition and stand structure caused by road fragmentation in forested peatlands
Northern Alberta, Canada
Graduate Student
M.Sc. (Conservation Biology) (Fall 2015-2017)
Supervisor
Associate Professor & Alberta Biodiversity Conservation Chair
Status: Completed, Msc Student Thesis Defended

When a road is built through a peatland with horizontal water flow, the road can act as a dam; as a result, trees on the “upstream” side of a road can become waterlogged and either die or become stunted, whereas on the “downstream” side of a road, a prolonged drop in the water table can cause the trees to root deeper and grow taller than what is average in the wetland. Interestingly, this phenomenon does not occur consistently. In fact, the same road constructed through two different wetlands may disrupt tree growth patterns in one wetland whereas the other location may appear unaffected. This study examines the conditions that maintain wetlands: landscape position and soil substrate in wetlands with road disturbances and compares the magnitude of stand structure and vegetation changes among different peatland types. We used LiDAR derived tree canopy height and cover from 96 peatlands and vegetation field sample plots from 48 peatlands in North Eastern Alberta. We analyzed the data using Generalized Linear Mixed models to explain the variation in canopy height and cover. Results from this study are anticipated to help guide management decisions for building roads through areas with complex forested wetlands by identifying peatland and substrate types that are more susceptible to road impacts.