*Repost from Nantucket Conservation Foundation' Science and Stewardship Blog Nov 2012*
There are a few local legends about how deer first came to live on Nantucket that range from deer swimming from the Cape (16 miles at the shortest point) to deer being purposefully brought to the island in the 1920s for hunting. Looking at archaeological evidence, deer have likely been present since Nantucket became an island but over hunting drastically decreased populations until deer were re-introduced for hunting purposes. However they officially got to our little island, deer are definitely here to stay.
The Massachusetts Division of Fisheries and Wildlife estimates 45-55 deer per square mile on Nantucket – no matter how you slice it, that’s a lot of deer in one place. Increasing deer populations are having negative impacts on native plant communities across New England and the Midwest states. Impacts range from decreasing native and rare plants to increasing populations of invasive plants. Scientists typically study the impacts of deer by constructing deer exclosures – tall fences designed to keep deer out of an area. While those exclosures are in place, typically for 5-10 years, researchers monitor plant populations inside and outside of the fence. We can see if some plants grow inside the exclosure but not outside of it where deer browsing pressure is high – we can also see if plant density is higher inside the fence.
On Nantucket, we have been observing high deer densities and hence, high deer pressures for a long time now – long enough that we don’t have a good idea of what many plant communities on island would look like without deer grazing. Some of the unique habitats that we study on Nantucket, the sandplain grasslands and coastal heathlands tend to be disturbance driven – they thrive when disturbance is present, prescribed fire, grazing, etc. We started to wonder what/if any effect deer browsing might be having on these unique communities so we decided to set up a deer browse experiment.
In 2011, the NCF maintenance staff constructed a 50x50ft fence, tall enough to keep deer out. If you hike at our Sanford Farm property, you can’t miss this large fence – located on the shorter hiking loop from the parking lot. For the next 5 years (at least) we will be monitoring vegetation plots both inside and outside of this fence to see what happens to the plant communities when deer can no longer browse them.
Sanford Farm is a perfect place to study the effects of deer browsing – as anyone who walks this area can tell you, there are a lot of deer and a lot of deer sign (deer trails, scat,etc.). Additionally, this area has a high abundance of several rare plants species palatable to deer – sandplain blue-eyed grass, bushy rockrose, New England blazing star). Hopefully this study will help us understand how deer are influencing this unique landscape.
On a side note: As the shotgun hunting season starts on Nantucket this week, please be aware of the Foundation's hunting regulations and restrictions.