Growing Deer Population Threatens Native Species—or How Bambi is Morphing into Godzilla

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Deer munching in a garden. Photo by Amy Roberts.

Whitetail deer were brought to the Virgin Islands from the US mainland more than once, and when a St. Thomas family imported deer to their Lameshure property on St. John in the 1920’s, they were looking to provide hunters with a steady source of sport and meat. They had no idea that decades later, the population of deer would explode and endanger the entire ecosystem of the island.

Herds of deer now roam unmolested through carefully tended gardens and natural protected areas as they consume almost every type of plant species on the island.

The effects of deer on the island’s vegetation is nothing short of alarming, according to Eleanor Gibney, an expert in plant native species.  “I’ve done a lot of looking, and it’s mind-blowing,” she said.  “There are areas where there’s nothing below the browse line.  No seedlings.  Nothing.”

The “browse line” refers to height at which mature deer can reach to feed on leaves and herbaceous vegetation.

Deer feeding patterns affect terrestrial and marine life

Gibney said the deer could totally change the upland forest composition, and also do incalculable damage by eating mangrove seedlings which grow along the shoreline.  In the territory, all species of mangroves are protected because they serve as buffers from storm surge during hurricanes.

“What’s gotten the attention of marine biologists is that deer like to eat mangroves, particularly red mangroves,” said Gibney.   “In coastal areas where there’s a high concentration of deer, like Lameshure, there are no mangrove seedlings whatsoever, or any mangroves less than ten years old.”

Deer grazing by black mangroves. Photo by Gail Karlsson.

In the past when a major hurricane like Hugo or Marilyn hit, the mangroves recovered quickly, according to Gibney.  Now if a hurricane blasts St. John, there will be no mangrove seedlings to take root, and any new ones that are produced would likely be eaten by the hungry deer.

If the mangroves can’t repopulate, there will be little to prevent the sea from flooding low coastal areas that were formerly protected. The damage can come from another direction as well; mangroves also protect coral reefs from sediment and contaminants that wash down hills in the runoff following heavy rains.

“The damage the deer are doing and repercussions could be disastrous,” said Gibney.

“Any plant is vulnerable to deer,” said Gibney.  “Apart from mangroves, we have a dozen seriously endangered plants from St. John, and about 30 species of high concern.  The deer are eating the seedlings of at least one of the two plant species that are unique to St. John, found nowhere else in the world”, she said.

Gibney said twelve species of native orchids grow on St. John, and the deer eat all of them. “One species of orchid has been completely extirpated from the National Park.  The few that remain on island exist only in a south shore subdivision, she added.

Although Gibney characterizes the native plants on St. John as “tough and resistant,” she says they’re not able to withstand the constant browsing. Aside from “one or two plant families that the deer tend to avoid,” the deer consume most native and imported plants. “They even eat the things goats don’t eat,” she said.

Damage to trees from deer on the road to Annaberg and Francis Bay. Photo by Gail Karlsson.

Dr. Gary Ray, an ecologist based on St. John, said deer like to “graze” (eat herbaceous, grasslike plants) as well as “browse” (consume shrubs and trees, more woody plants.)

The signs of the damage caused by deer are visible to anyone who knows what to look for:  In areas where deer thrive, there is little vegetation below the browse line.

St. John residents, who are all too aware of how deer plunder their gardens, are now seeing their effects in forested areas.  “Up until five or six years ago, you could not see through or walk through the growth on my property in Coral Bay,” said Julie Fortunato, “and now you can.”

Gibney said there are places where it’s possible to see into the forest for as far as 300 feet.

The browse lines are particularly visible in areas that were pasture lands and cattle estates until the mid-20th century—areas like Lameshure Bay, Reef Bay, and Maho Bay, where recent secondary vegetation tends to be leafier near the ground.

But aside from the highly visible effects, there are uncountable unknown repercussions from the deer browsing, according to Gibney.  “Maybe a species of insect or bird is totally reliant on the leaves or fruit of a particular native plant, and they may in turn be the only pollinators or seed dispersers of other native plants. St John is unique in the region for the diverse native vegetation under protection from development. It’s a precious legacy that’s getting destroyed very fast.”

Deer population surges

Gibney grew up on St. John but said she never saw a deer until the mid 1970’s.  Sightings became more frequent in the late 1980’s.

She noted that the deer population started to increase dramatically between 1995 and 2015, a 20-year period in which no serious droughts occurred, and vegetation became abundant.

Deer no longer have natural predators on the island. Hunting was outlawed in the Virgin Islands decades ago (although there are rumors of clandestine hunting still going on).  Packs of stray dogs, which used to roam in parts of the island and presumably feed on deer, have been rounded up in recent years, largely due to the efforts of the Animal Care Center.

No one knows if the deer population on St. John numbers is in the hundreds or even thousands.

“We’re reluctant to put out any facts about their number and range, and less inclined to discuss whether it’s growing or declining,” said Thomas Kelley, the natural resource manager for the Virgin Islands National Park.

The park is responsible for managing the wildlife within its boundaries.  They have plans for most of the larger mammals–rats, cats, mongoose, sheep, goats and hogs.

Developing a management plan is a multistep process that can take many months, according to Kelley.  The park is required by the National Environmental Policy Act (NEPA) to coordinate with federal and territorial agencies, file documents, conduct studies, and hold public hearings before the plan can be implemented.

“When you hold a public meeting about killing deer, it will be controversial,” observed Julie Fortunato.

“People romanticize deer as ‘wild creatures.’  There will be more resistance than the plans for managing other non-native animals like goats and pigs,” Gibney admitted.

Facing budget cuts, the National Park and other wildlife agencies are struggling to find the funding for the research required to develop a management plan.

Gibney said the lack of funding has prevented the park from hiring someone to take the lead.  “The VI National Park has never had a terrestrial biologist on staff,” said Gibney.  If they did, we would have had a deer control program in place eight years ago.”

She would like to see the National Park and the U.S. Department of Agriculture collaborate to establish a deer culling program.  “It really is inhumane to let populations breed uncontrollably.”

It would not be the first time that deer were culled on St. John. In October 2014, a portion of the herd of deer at Caneel Bay Resort was euthanized by members of the U.S. Agriculture Department’s Animal and Plant Inspection Service. The animals had become debilitated following a tick infestation, according to Patrick Kidd, Caneel’s director of marketing.

Gibney worked for many years as a horticulturalist at Caneel Bay. She said that Laurance Rockefeller, who founded the Virgin Islands National Park and established the resort at Caneel Bay, would never have tolerated the deer on the resort’s grounds. “He was a plant person, the trees and grounds at Caneel were very important to him” she said.

1 COMMENT

  1. Nothing is going to be easy about this. If the money was there, you could possible launch a full scale catch and neuter by injecting the females with birth control. Non native species wreck havoc throughout the Caribbean. Removal? Expensive and very time consuming and where would you take them?