North Wildwood Boulevard (NJ Route 147)
Terrapin Barrier Fence Project
Submitted to: New Jersey Department of Transportation
Regarding: Preliminary plans for a proposed terrapin barrier fence on North Wildwood
Boulevard (NJ Route 147), which was initiated by the North Wildwood Terrapin Rescue,
a citizen-based conservation organization
Prepared by: The Wetlands Institute, 1075 Stone Harbor Boulevard, Stone Harbor, NJ 08247
December 14, 2010
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Table of Contents
Cover Sheet................................................................................................................................................... 1
Table of Contents ......................................................................................................................................... 2
Background ................................................................................................................................................ 3-4
Terrapin barrier fences.............................................................................................................................. 5-6
North Wildwood Terrapin Rescue ............................................................................................................ 6-7
Project details .......................................................................................................................................... 8-11
Conclusion…………………………………………………………………………………………………………………………………………….12
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Background
Right here in New Jersey lives one of the most remarkable turtles on the planet, the northern
diamondback terrapin (Malaclemys terrapin terrapin). Of the roughly 300 known species of
living turtles in the world, diamondback terrapins are the only ones exclusively adapted to life
in the brackish waters of coastal salt marshes. Terrapins play an important ecological role in
salt marsh ecosystems. Terrapin eggs, hatchlings, and juveniles are heavily preyed upon by a
wide range of predators including foxes, raccoons, skunks, crows, gulls, bald eagles, crabs and
large fish. The relatively few terrapins that survive to adulthood, however, are at the top of the
salt marsh food web and help keep populations of other animals from growing destructively
large. For example, in some southern coastal states, periwinkles, which are small snails that
terrapins are particularly fond of snacking upon, have undergone population explosions which
have resulted in large-scale degradation of salt marsh habitats.
Before human development of coastal barrier beach islands, terrapins nested on barrier
island sand dunes. However, most of this natural habitat has been leveled to create nearly
continuous resort communities along the Jersey shore. Consequently, female terrapins have
had to find a suitable alternative location to lay their eggs. Today, sadly, most of the readily
available nesting sites for terrapins in southern New Jersey are the shoulders of heavily
trafficked roads crossing and adjacent to salt marshes. The result is that an appalling number of
nesting females are killed by motor vehicles each year (Figure 1).
Figure 1 – A nest-seeking female terrapin approaches a busy road.
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Figure 2 – An egg-carrying female terrapin is crushed to death by a vehicle on a salt marsh road.
Since 1989, during terrapin nesting season (late May – mid July), The Wetlands Institute has
sent out road patrols around the clock every day to help nesting females cross roads safely. We
also record the number of female terrapin road mortalities (Figure 2). The carnage of adult
female terrapins on roads crossing and adjacent to coastal salt marshes during the annual
nesting season, which unfortunately coincides with the start of the summer tourist season, has
resulted in an annual average of 500 to 700 egg-laying female terrapins being killed by
motorists just along the coast of Cape May County. Over the 20 years that researchers from
The Wetlands Institute have been monitoring terrapin road kills, over 11,000 terrapin deaths
have been documented (refer to Figure 3 for more information on our long-term study site).
Figure 3 - The Wetlands Institute’s road patrol transect is highlighted in red. The locations of terrapin barrier fences within
transect are highlighted in blue.
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Terrapin barrier fences
To mitigate the terrapin road mortality problem, The Wetlands Institute conducted
experiments to find out whether roadside fencing might be an effective means of preventing
nest-seeking female terrapins from wandering onto the heavily-trafficked summertime roads.
Our research has demonstrated that terrapin barrier fences significantly reduce the number of
terrapin road kills. Their widespread use in appropriate places can save hundreds of terrapin
lives every nesting season (refer to Figure 4).
Terrapin barrier fence
installed
Terrapin barrier fence installed
Figure 4 – Data suggesting the effectiveness of terrapin barrier fences in reducing female terrapin road mortalities
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Furthermore, terrapin-free roads are much safer for people to drive on. The amount of
unexpected braking and sudden swerving to avoid hitting terrapins in the road is greatly
reduced. And there will be fewer well-intentioned drivers getting out of their vehicles and
putting themselves at risk to rescue terrapins wandering across traffic lanes.
Collaboration between volunteers, governmental agencies, local businesses, and The
Wetlands Institute has resulted in approximately six miles of terrapin barrier fences being
installed in recent years. The Wetlands Institute has an essential role in terrapin barrier fence
projects on Stone Harbor Boulevard, Avalon Boulevard, the Whale Beach section of Landis
Avenue in Sea Isle City, Roosevelt Boulevard (34th Street, Ocean City), Longport-Somers Point
Boulevard, and the Margate Causeway. The role The Wetlands Institute plays is to encourage
concerned citizens, as well as private and public agencies, to become involved. The Wetlands
Institute is committed to help the North Wildwood Terrapin Rescue with technical advice, by
offering access to our long-term road kill data, and by providing some necessary fence building
tools. This community-based conservation project should: (1) reduce the number of nesting
female terrapins killed on North Wildwood Boulevard; (2) make our roads safer for driving; (3)
encourage citizen science; (4) strengthen the local community; and (5) create awareness about
local wildlife conservation issues (Figure 5).
Figure 5 - In May 2010, volunteers installed over 7200 feet of corrugated tube barrier on Margate Causeway. Students from
Atlantic City High School’s Junior Navy ROTC learned about terrapins from experts while helping us install this barrier fence.
North Wildwood Terrapin Rescue
In late May of 2010, a North Wildwood summer resident, Patrice Dorfman, contacted The
Wetlands Institute regarding her concern for the unsettling number of terrapins being killed by
vehicles on North Wildwood Boulevard (NJ Route 147). The Wetlands Institute has never
officially monitored North Wildwood Boulevard for terrapin road mortalities, although
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anecdotally we know that a lot of terrapins are killed there every year. Logistically, researchers
at The Wetlands Institute cannot include North Wildwood Boulevard in their five-times-a-day
road patrol during terrapin nesting season.
For the first time, in the summer of 2010, Patrice Dorfman and her nephew Nicholas Plagge
have documented the extent of the terrapin road mortality problem on North Wildwood
Boulevard. The Wetlands Institute’s Research Director, Dr. Roger Wood, and Research and
Conservation Coordinator, Dan McLaughlin, provided the necessary training and materials (data
sheets and safety vests) to ensure data were collected according to The Wetlands Institute’s
protocol.
Over the course of the 2010 nesting season, 82 terrapin road mortalities were documented
on North Wildwood Boulevard (NJ Route 147) and an additional ten uninjured terrapins were
moved off the road to safety by Ms. Dorfman and Mr. Plagge.
Ms. Dorfman and Mr. Plagge are now spearheading a campaign for the installation of a
terrapin barrier fence on North Wildwood Boulevard (NJ Route 147), which should drastically
reduce terrapin road mortalities on this heavily travelled highway. Their citizen-based
conservation organization is called the North Wildwood Terrapin Rescue. The organization
plans to raise awareness about the plight of the diamondback terrapin. They also plan to raise
the necessary funds to install a terrapin barrier fence along North Wildwood Boulevard. They
would like to organize a community-based terrapin barrier fence installation on North
Wildwood Boulevard before the 2011 terrapin nesting season.
The Wetlands Institute is committed to help the North Wildwood Terrapin Rescue. In
September 2010, The Wetlands Institute hosted a press conference in which State Senator Jeff
Van Drew publically supported the goals of the North Wildwood Terrapin Rescue and The
Wetlands Institute (Figure 6). The event generated significant media coverage and produced an
influx of volunteer support (please visit http://site.terrapinrescue.org/Save_The_Terrapins__NORTH_.html to view some of the articles).
Figure 6 - New Jersey State Senator Jeff Van Drew holds a terrapin at a press conference, hosted by The Wetlands Institute,
regarding the proposed North Wildwood Boulevard terrapin barrier fence project
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Project details
The portion of North Wildwood Boulevard (NJ Route 147) that crosses salt marsh (terrapin
habitat) is approximately 2.5 miles long. Installing terrapin barrier fence along both sides of the
road (about 26,500 feet) should drastically reduce the number of terrapin road mortalities
(Figure 7).
Stone Harbor
Point
North Wildwood
Figure 7 - Satellite image of proposed project site on North Wildwood Boulevard (highlighted yellow)
Fortunately, about 75% of North Wildwood Boulevard has a safety guardrail paralleling the
road. For these sections, we propose installing a terrapin barrier made from chicken wire, or a
material like it. We will secure the chicken wire to the guardrail using zip ties. This particular
terrapin barrier fence design is very unobtrusive, inexpensive, and less labor intensive than
other types of barrier fence. This design will not compromise the function of the guardrail, so it
is also safe for drivers.
In April 2010, seventh and eighth grade volunteers from Jordan Road School in Somers Point,
NJ installed a terrapin barrier fence by securing chicken wire to guardrail along 2000 feet of
Longport-Somers Point Boulevard. Researchers at The Wetlands Institute provided technical
assistance. The fence proved to be an effective barrier, as well as indistinguishable from the
guardrail. Please refer to Figures 8 – 9.
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Figure 8 – Student volunteers attach a chicken wire terrapin barrier to a guardrail on Longport-Somers Point Boulevard.
Figure 9 - Close up of zip ties securing chicken wire terrapin barrier fence to a guardrail
For the sections of North Wildwood Boulevard not paralleled by guardrail, we propose
installing a low-profile corrugated tube, which is the newest and most innovative terrapin
barrier fence design employed by researchers at The Wetlands Institute. We recommend using
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a six or eight inch diameter high density polypropylene corrugated tube (which is black in
color). Thirty six inch long zip ties secure the tube to wooden stakes, which would previously be
hammered into the ground. This design has already been approved for use on county-owned
roads by Cape May County Engineer, Dale Foster (Figure 10).
Figure 10 – Corrugated tube terrapin barrier fence secured to a wooden stake by a zip tie
In May 2010, researchers from The Wetlands Institute helped volunteers of the Margate
Terrapin Rescue install over 7200 feet of this durable corrugated tube design along Margate
Causeway. The tube is durable and effective as a barrier which makes it a strong candidate for
a long term solution to terrapin road mortalities (Figure 11).
Figure 11 – A section of corrugated tube terrapin barrier fence installed on Margate Causeway
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Under the New Jersey Department of Transportation’s direction, we will install gates
wherever access is required. In 2010, we installed gates in terrapin barrier fences on Margate
Causeway and Landis Avenue in Sea Isle City (Figure 12). The gates were designed by retired
physicist and Wetlands Institute Research Committee member, Dr. John Cuthbert. They are
designed to be easily removed, which provides access to areas behind the terrapin barrier
fence. The gates are also easy to put back in place, which will reconnect the continuous and
inconspicuous barrier fence.
Figure 12 – In June 2010, Dr. John Cuthbert and student researchers from The Wetlands Institute installed an access gate
along a section of corrugated tube barrier on Margate Causeway.
The North Wildwood Terrapin Rescue would like to install the terrapin barrier fence through
a citizen-based operation with supervision being provided by The Wetlands Institute and the
New Jersey Department of Transportation. Researchers at The Wetlands Institute have the
required expertise to supervise a terrapin barrier fence installation that will minimize the
number of terrapins able to breach the barrier. In addition, maximizing terrapin nesting habitat
is an essential consideration in determining the exact location of the barrier fence. We have
worked closely with the Cape May County Engineer, Dale Foster, on several terrapin barrier
fence projects and also understand the importance of allowing enough space on the shoulder
of roads for vehicles. This must be considered for the sections of road without guardrail and we
will seek consultation from the New Jersey Department of Transportation.
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Conclusion
Researchers at The Wetlands Institute envision this terrapin barrier fence plan as a
potentially effective solution to the large number of terrapin road mortalities observed on
North Wildwood Boulevard (NJ Route 147) every terrapin nesting season. Patrice Dorfman and
Nick Plagge confirmed that a substantial number of female terrapins are killed on North
Wildwood Boulevard during terrapin nesting season (82 terrapin mortalities in 2010). Ms.
Dorfman and Mr. Plagge have generated considerable momentum by creating the North
Wildwood Terrapin Rescue, recruiting volunteers, and gaining the support of State Senator Jeff
Van Drew.
The Wetlands Institute is a listed “Potential Partnership to Deliver Conservation” on page
104 of the New Jersey Division of Fish and Wildlife’s Wildlife Action Plan. It is our hope that the
New Jersey Department of Transportation, the North Wildwood Terrapin Rescue, The Wetlands
Institute, and local volunteers will be able to work together to address the female terrapin road
mortality problem on North Wildwood Boulevard (NJ Route 147). Please do not hesitate to
contact Dan McLaughlin, for more detailed information, at (609) 368-1211, or
research@wetlandsinstitute.org.
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