Understory Biodiversity Plantings within Canopy Gaps in the King Creek Watershed of Haida Gwaii

Abstract

This project involved understory plantings at five sites in canopy gaps created in a riparian spacing prescription in the upper Yakoun watershed of Haida Gwaii. Five species were selected as high potential for understory restoration (Highbush cranberry (Viburnum edule), Western yew (Taxus brevifolia), Pacific crabapple (Malus fusca), Devil's club (Oplopanax horridus), Stink currant (Ribes bracteosum) based on three criteria (Haida cultural value, ability to reach free growing height (>1.5m), and berries used and dispersed by wildlife). If these species can become successfully established they may contribute to landscape level diversity through seed dispersal processes. A monitoring program was designed to measure the success of the understory plantings and to develop an understanding of natural revegetation of the shrub layer in canopy gaps. Canopy openness was measured with smartphone spherical photography at the centre of each gap to track changes in light availability in the gaps through time. This project aims to explore the opportunity created by canopy gaps to mitigate adverse impacts of introduced Sitka black tailed deer (Odocoileus hemionus sitkensis) on understory richness, by expanding existing silviculture methods to include important understory species.