Vegetation restoration on Reef Island

  • Mar. 13, 2009 7:00 p.m.

Submitted by RGIS– Since 1997, the Research Group on Introduced Species (RGIS), a consortium of researchers including Dr. Jean-Louis Martin, from Montpellier, France and Dr. Tony Gaston of Environment Canada, has been studying changes in Haida Gwaii forest vegetation and native animals that depend on it. These changes are a mainly a result of the introduction of deer a century ago. Part of their experimental research strategy has included reducing deer numbers on remote Reef Island in Laskeek Bay to observe the recovery of the vegetation. Over the past decade the density of deer on the island has been maintained at less than 25-percent of pre-cull level. The result of this reduction is a remarkable recovery both in forest understorey plants and in vegetation of the shoreline.To fully understand the recovery process, the team is hoping to eliminate the last deer on the island, because even very low deer densities have a strong effect on their favourite food plants, such as salmonberry, huckleberry and deer fern. However, the deer have proven wily and a few have managed to evade the best efforts of hunters. Consequently, last summer and fall, a variety of new techniques for finding or attracting deer were tested in the hope that deer resistant to normal hunting methods might prove susceptible to other techniques. Once eradicated, it is not expected that deer would remain absent from the islands for long, because genetic evidence suggests that recolonization would probably occur over time. However, the interim deer-free period allows researchers to assess vegetation recovery in the absence of deer.Last summer, a variety of attractants, including scent and food baits were deployed, along with automatic cameras set up to record any deer visits. The resulting pictures showed a minimum of eight deer visiting the bait stations. Two more individuals seen by observers were recognisably different from those in the pictures, so we had a minimum of ten deer on the island, one of which later gave birth to a fawn. Given that only a small portion of the island was covered by observers and cameras, we think there were approximately 30 deer present on the island – about half the number present in 1997 at the start of the project. To maintain the reduced density of the deer population, a small hunting party including Jake Pattison and Carita Bergman, supported by Malcolm Hyatt, visited the island in October. After 9 days of hunting, they succeeded in taking ten deer, despite the challenges presented by the wet and stormy fall weather. During their stay, a major storm rolled through with 10 metre waves thrashing the island, causing the ground they were camping on to shake at night!Despite the continued presence of deer, the vegetation of Reef Island, especially less-preferred plants like sword fern and salal, continues to expand. Because of the expansion of the food supply, it is clear that if deer recovery proceeds there will be a point reached when the deer population greatly exceeds the density present before culling began. It could be that in future we can maintain the population on Reef Island at a level where the native vegetation is restored while a healthy deer population is maintained. We hope that continued research on Reef Island will allow us to determine the optimal level of deer density that can coexist with native vegetation diversity and tree regeneration. Finding that balance and discovering cost-effective methods of maintaining it are our future aims. RGIS thanks our partners (Parks Canada, Environment Canada, Centre for National Research in France and Laskeek Bay Conservation Society) and Gwaii Forest Society for support for the success of this year’s work.