Comparing Percent Cover of Select Invasive Plant Species (Rubus armeniacus, Ilex aquifolum, and Hedera helix) at Salish Creek and Canyon Creek in Pacific Spirit Park

Abstract

Understanding the effect of invasive species is becoming increasingly important as they can directly impact the health of ecosystems. This study investigates the percent coverage of three select invasive species within Pacific Spirit Park: Himalayan Blackberry, English Holly, and English Ivy, specifically along Salish and Canyon Creek. Sampling was done by laying a transect line at the stream bank and at forest regions at both creeks, followed by calculation of percent cover for each species within random plots along the transect lines. No significant difference was found between the percent cover of invasive species at the two streams, with a p-value of 0.61927; yet data demonstrated that there was a significantly higher mean percent cover of invasive species within the forest at both creeks than at their respective streams, with a p-value of 0.01658. This can be explained by the similarity between Salish and Canyon environments and by the level of human activity between forests and streams and, implying that more disturbed sites (i.e. sites heavily affected by anthropogenic activity) are more susceptible to invasive species immigration. Thus, our findings suggest that removal efforts of invasive species at Pacific Spirit Park be focused on the forest regions.