SpruceRoots Magazine - September 2001

 

REEF, LOW & LIMESTONE

by Jean-Louis Martin, RGIS

On June 27 the Research Group on Introduced Species invited guests from communities on-Island to its main study site at Laskeek Bay.

The outing was organised to share the findings of the Research Group on Introduced Species (RGIS) project and to show comparative vegetation and fauna on islands with deer (East Limestone) to islands with no deer (Low island), or that had deer but where they had been culled 4 years ago (Reef Island).

The people who flew down to Laskeek camp were Shirley Kircheldorf (Masset Village Council), Dwight Welwood (Port Clements Village Council), Barb Wilson (Skidegate), Gary Wunsch (Queen Charlotte Management Committee), Tony Smith (Graham Island Advisory Planning Committee), Kiku Dhanwant (CHN Forest Guardians), Simon Davies (SpruceRoots Magazine) and Alyssa King (The Observer).
The party was welcomed by Dr. Jean-Louis Martin from the Centre National de la Recherche Scientifique (CNRS) in France who represented RGIS and by Charlotte Tarver of the Laskeek Bay Conservation Society (LBCS). The Society is one of the founding members of RGIS.

The visit started at East Limestone Island, where since 1989, LBCS has operated a volunteer-based project, monitoring marine and terrestrial organisms with a special emphasis on Ancient Murrelets. The visit to Limestone was to show participants the features that characterise forests that have been heavily browsed by deer. The island has become an open park-like landscape with a mossy understory, the absence of berry-bearing bushes, a total absence of regenerating Western red cedar, and a delayed regeneration of Sitka spruce. The group also stopped at exclosures on the island that were installed to serve as controls for the deer cull on Reef Island and as an educational tool-the exclosures show that the amount and diversity of plant life is much higher inside than outside the exclosure where deer are present.

The interactions between deer, squirrels and songbirds also stirred interest with the group. Squirrels affect songbirds by eating their eggs and nestlings. RGIS research revealed that the level of predation by squirrels is closely related to the abundance of spruce cones, their main food. Hence nest predation fluctuates from year to year in synchrony with fluctuations in squirrel abundance which is driven by fluctuations in cone production. The predation of nests is also affected by the deer browsing that opens up the understory. With the understory open, nests become more visible and more likely to be found by other predators like crows and ravens

 

Understory on island with deer

 

 

 

 

 

 

Understory on island without deer

 

 

 

 

After setting the stage on East Limestone guests headed by boat to Low Island. The remote nature and relatively small size (10 ha), combined with a rugged coastline has prevented Low Island from being colonized by deer. Only three other forested islands with no sign of current or past deer presence are known on the east coast of Haida Gwaii-South Low and Lost Island both in Laskeek Bay and Tar Island, off Lyell Island.

On Low Island, the group was welcomed by a profusion of flowers growing in every single crack and soil patch found along the rocky shoreline. The abundance of Lupin, Indian paint brush, Black lilly to name just a few, contrasts remarkably with the barren rocks that surround East Limestone Island. The forest interior was equally remarkable, here the lush dense shrubs and ferns make it a real challenge to move through the forest. The type and abundance of shrubs varies from site to site in response to canopy closure and soil quality. It varies from a 3 to 4 m high Salmonberry grove that forces you to crawl, to a more open mix of Salal, Red huckleberry and Ferns in the more typical forest interior. Research by RGIS has shown that songbirds are three to seven times more abundant on Low than on a similar sized island with deer. Songbird reproductive success is also higher on islands without deer.

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Retracing their steps to the shoreline the group embarked for the 249 hectare Reef Island. The island was home until 1997, to about 70 Black tailed deer which had turned most of it to the park-like forest that is seen on East Limestone. Deer are the only introduced mammal on Reef Island.

Between 1995 and 1997 RGIS researchers established 22 permanent study plots in the forest interior, and 15 plots on the shoreline, to collect pre deer-cull data on vegetation and songbirds. During the winter of 1997-1998 deer were culled. Regular culls have occurred since to prevent population recovery. Since this program was instituted the vegetation and the song birds have been monitored to document and understand how they respond to this dramatic reduction in deer. After only 3 years of growth the changes are already remarkable. The young spruce that were repeatedly browsed back before, have resumed normal and vigorous growth. Fifty to 70 year old red huckleberry stems are finally able to rejuvenate by producing new shoots at their base that now reach a height averaging 1.5 m. Depending on the site, different slopes are covered with ferns or huckleberry bushes. Seedlings of Crabapple, Alder, False Azalea, and Salal are now found in great abundance, whereas, they were entirely missing before the cull, and finally, vegetation sampling by RGIS this year has shown that young cedar 0.3 m in height or more are now a common sight in all sites with mature cedar. Not a single cedar seedling had been observed in the hundreds of vegetation samples that took place before the cull. The pattern on the shoreline is identical, confirming that when browsing pressure is sufficiently reduced even plants that seemed to be entirely extirpated can make it back in a short period of time.

This recovery has been remarkable to witness, but there was even more for guests to absorb. RGIS student, Bruno Vila, explained how a study of the tree and shrub growth-rings and of the scars left by browsing or antler rubbing can help show the history of deer colonization and Sylvain Allombert, who is working on insects took the visitors' breath away when he revealed RGIS findings on the huge reduction of insect abundance and diversity observed when comparing islands with deer to islands with no deer. This work, and his graphic illustration of it, provided the missing link and helps to show the cascade of effects connecting deer, plants, insects and birds.

Throughout the day all of this new information fuelled very lively discussion on the pros and cons of a deer cull and the remarkable difference in islands that have deer on them and islands that do not. Members in the group wanted their friends and neighbours in the community to see for themselves the clear and remarkable differences. There was also discussion about the benefits of ensuring that islands such as Reef and SGaang Gwaii be maintained without or at least with very little deer, to serve as reference of how the forests of Haida Gwaii were before the deer changed them. ·

For more information or to contact RGIS: Barb Rowsell, project coordinator, rgis@qcislands.net or telephone: 250 559 2345

SpruceRoots Magazine - September 2001