March 5, 2009

 

By Lindsay Key ‘11MFA

 

UNCW environmental scientists Anthony Snider and John Taggart are helping the Bald Head Island Conservancy determine whether the island’s rapidly increasing white-tailed deer population is restricted to the immediate area, and what impact the deer are having on its maritime forest. Hunting is not allowed on the island and the animals have no natural predators there. 

 

Taggart, in building on the 2008 research of former UNCW professor Steven Brewer, is studying the diet of the deer and what effects their grazing habits might have on the island’s vegetation.  Taggart is studying Live Oak tree seedlings and saplings most closely, by placing 12’ x 12’ wooden fence exclosures around established tree plots.  Over the next two years, he will compare the health of the quarantined trees to the health of those accessible to the deer.

 

The Live Oak tree is the keystone species in the maritime forest, according to Suzanne Dorsey, executive director of the Bald Head Island Conservancy.

 

“It is a salt tolerant tree and functionally is important because that beautiful canopy, so picturesque, actually serves to knit together the entire canopy in the forest,” explained Dorsey. “When hurricane force winds hit the forest the canopy will shear the wind off, keeping it out of the understory. It prevents tree falls by protecting the understory. It is so important to our maritime forest because without this species we couldn't survivehurricanesnearly as well.”

 

If the deer are found to be overgrazing on the Live Oak tree population, then they could alter the entire island’s ecosystem.  Consequently, the issue of how to manage the deer population has been a source of contention on the island for more than five years.  While most residents are in agreement that the population must be controlled, they are divided on whether to use lethal or non-lethal means, Dorsey said. 

 

Currently, the village brings in sharp shooters each winter to reduce the population.  But some residents argue that gun firing on a four-mile long strictly residential landscape is a safety hazard.  Others stress that the killing of the animals isn’t warranted until researchers determine exactly what impact they are having on the forest.

 

The conservancy will be closer to understanding if one non-lethal method is an option when Snider completes his research on the movement and habitat use of the population.  If he finds that the deer are not intermingling with other deer in the Smith Island marshes or at Fort Fisher, then the conservancy may be qualified to tranquilize and inject the deer with an experimental drug called PZP, an immunocontraceptive that functions as deer birth control. 

 

However, this method would not be suitable if the population is open and injected deer could be hunted and eaten, Dorsey said, as the drug has yet to be tested for its effect on humans. 

 

In his research, Snider is assisted by NC State graduate student Brandon Sherrill and North Carolina Coastal Reserve employee Paula Gillikin, who visit the island to tranquilize and tag the deer with radio collars.  Over the next year, they will monitor the migration patterns of the deer; so far,zero have moved outside the island’s population.

 

Meanwhile, several environmental studies graduate students at UNCW have expressed interest in expanding Snider’s research into a long-term multi-year monitoring project—especially if the immunocontraceptive is approved.

 

 “The population dynamics of white tail deer have been in the literature for some time but not very many studieson islands- this is the first aspect that caught my attention,” wrote environmental studies graduate student Andy Almeider in an e-mail. “The potential for non-lethal means ofpopulation controlis also of interest; coming froma veterinary background, I am incredibly interested in how immunocontraceptive use will alter their migration and population dynamics.”

 

UNCW’s research is funded by the Village of Bald Head Island through the Bald Head Island Conservancy.

 

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UNCW/Jamie Moncrief. Bald Head Island.