Block Island Deer Population to be Culled

By ecoRI News staff

The Rhode Island Department of Environmental Management (DEM) has filed emergency regulations establishing a non-recreational program to reduce the overpopulation of Virginia white-tailed deer that currently presents an imminent risk to the health, safety and welfare of Block Island’s natural resources.

DEM said it has determined that implementation of a non-recreational deer reduction program is required in order to protect the fragile habitats and natural communities found on Block Island.

The density of white-tailed deer in the 9.75-square-mile town of New Shoreham is estimated at 80-100 deer per square mile. This estimated population range was established by direct counts from an aerial sampling survey, and is about eight to 10 times the desirable level for cultural tolerance and ecological health on Block Island, according to DEM.

The town and its residents have raised concerns about crop and landscape damage caused by the excess deer population and impacts on the Island’s ecosystem.  Traditional management methods have been unsuccessful in reducing the Island’s deer population, according to DEM.

Scientists at DEM’s Division of Fish & Wildlife and The Nature Conservancy believe that the overabundance of deer on Block Island is also having long-term impacts on the Island’s ecology. The Nature Conservancy has documented negative effects of the white-tailed deer population on Block Island. The island has a wealth of unique species, including state and federally endangered/threatened species, and fragile habitats such as globally imperiled morainal grassland that are at risk from the overabundance of deer.

“The problems on Block Island are unique to the state,” DEM Director Janet Coit said. “The size of the deer population is substantially larger than that of any other community on the mainland, and is far beyond the capacity of the Island’s ecosystem system to withstand the damaging effects. These deer reduction techniques have been used effectively in other parts of the region and we look forward to obtaining similar results on Block Island.”

One of the plants on the island most affected is the state-endangered northern blazing star, which is found nowhere else in Rhode Island. Research conducted by The Nature Conservancy found that deer had consumed 97 percent of the Island’s unfenced northern blazing star wildflowers, thereby preventing most of this species from going to seed and sustaining the population.

In addition, the deer grazing on native plant species has caused a negative change in the habitat structure throughout Block Island. This has triggered a tremendous expansion of invasive plants inedible to deer, such as mile-a-minute weed vine and black swallowwort. This fundamental change in the habitat structure — from a healthy shrub community to a tangle of vines has a potential negative effect on migratory birds, mammals and butterflies, according to DEM.

The regulations, which allow DEM to conduct a bait and shoot culling operation, took effect immediately.