The movie, The Day After Tomorrow, was a Hollywood blockbuster that also made a bold social statement: Sea level rise and associated storm tides are a serious matter.
Although the tidal waves in the movie surging through the streets of New York City and upending vehicles were unrealistic, the movie stimulated city and state officials’ thinking from Boston to Miami Beach and beyond. At the recent conclusion of the Paris conference on global climate change, the world’s political leaders are finally admitting that human-induced climate change is a serious issue that can no longer be ignored.
Sea level rise in the Chesapeake Bay is hardly a new phenomenon. William Cronin’s excellent 2005 book, The Disappearing Islands of the Chesapeake, reports on the reduction or loss of 44 Bay islands since the Bay was first explored. A number of islands formerly supporting small communities had to be abandoned during the 19th and 20th centuries often because of frequent storm flooding.
One of the more dramatic changes occurred at Poplar Island in Talbot County, MD, the subject of my October 2015 commentary, “A watery phoenix, Poplar Island rises from the spoils alive with the songs of birds.” Another of the most notable losses is Sharp’s Island (with the pseudonym, Devon Island, in James Michener’s book, Chesapeake) where a 446-acre (1848 estimate) island that once supported farms, a hotel and a lighthouse reverted to open water by 1963. As part of the drowned Susquehanna River bed, many of the islands of recent geologic time were originally the higher areas of a vast ancient marshland complex that continued to lose ground after the end of the icy Pleistocene Epoch.
While Cronin’s book provided a detailed chronicle of events on each island, the focus of his book was on the islands’ human history.
Relatively little was presented on most of the islands’ wildlife with the exception of traditional waterfowl hunting at some of the islands. Few attempts had been made by state or federal agencies to conduct systematic wildlife censuses before the 1960s, therefore wildlife population data were very limited. In 1955, the U.S. Fish and Wildlife Service, in coordination with Maryland and Virginia, initiated the midwinter waterfowl inventory.
Breeding populations of wading birds (herons, egrets, ibises) and seabirds (gulls, terns, pelicans, cormorants) were largely overlooked until the late 1970s. As nongame, or “non-hunted” birds, less attention had been paid to these species by wildlife management agencies; though some of these species were considered to be indicators of environmental changes occurring along our coastlines.
The ramping-up of funding in the 1970s by federal and state wildlife agencies resulted in coordinated surveys in the Chesapeake Bay (Maryland and Virginia) and other U.S. Atlantic coastal states. Fortunately, these surveys continue to this day, although the frequency of the surveys, as well as level of funding, has been reduced over the years.
Except for some local studies, little attempt has been made to correlate habitat changes with breeding bird population changes in the Bay. One opportunity presented itself in 2009 as a result of a state of Virginia assessment of sea level rise in the Bay. A GIS mapping study of 15 islands in the Tangier Sound region of Virginia compared land area changes using aerial imagery from two different time periods, 1993–94 and 2007–8. These changes were then compared to the breeding population data of more than 20 waterbirds species (seabirds, wading birds, and ducks) over the same periods.
The 15 islands were all less than 100 acres, largely devoid of human presence, and therefore mostly under the radar of the public. As a result, changes could easily be missed.
An exception was Great Fox Island, where the Chesapeake Bay Foundation maintains an environmental education facility. CBF personnel were keenly aware of rising waters, marsh erosion and losses on Great Fox as repairs to docks and buildings were a constant challenge.
The results of the GIS analyses were dramatic. The group of islands lost 21 percent of their collective land area over the 15-year period, a rather staggering figure by geologic standards. Great Fox had lost 26 percent in that period, while the tiny — less than 1 acre — Upper Bernard lost the most: 59 percent of its area. For state officials and natural resource managers, this was a wake-up call.
Simultaneous with the island losses, breeding wildlife suffered a great deal. For example, the American black duck, a species of high concern among resource agencies, suffered a 66 percent decline in nesting while wading birds — 9 species — lost 51 percent. Two seabird species of concern along the Atlantic, the common tern and black skimmer, lost 96 percent and 70 percent, respectively. Other duck populations, mostly mallards and a few gadwall, also declined by more than half during this period.
Is this pattern a microcosm of the Chesapeake Bay’s condition? From a breeding bird perspective, the future does not look favorable, as there are few “new” islands or suitable habitats developing.
The exceptions are sites that the U.S. Army Corps of Engineers is developing as dredged material islands, such as Poplar Island in Talbot County. The Corps is also focusing on other Maryland sites south of Poplar at James and Barren islands.
In the past, Hart-Miller Island in the Upper Bay had been developed using dredged material but is now inactive and at capacity. The island has had significant wildlife use over the years, but breeding potential was limited because of predator pressures.
In the Lower Bay, Craney Island near Portsmouth, VA, is a large depository of dredged material.
These dredged island sites may at first appear to provide good habitat, but little wildlife management occurs at such sites. Predators such as foxes, coyotes, raccoons and skunks have proven to be major limiting factors for ground-nesting waterbirds at some of these sites in some years. Thus, the overall situation looks fairly grim for this group of species to find sufficient nesting habitat to sustain their populations in the future.
Poplar Island is an exception because the Corps and Maryland Port Administration has provided sufficient funding for habitat creation, wildlife monitoring and management — including predator control.
The optimist might suggest that, because birds are highly mobile, they can seek islands in other regions to the north or south of the Bay. But similar island losses may be taking place in other areas. To wit, islands along western Long Island, NY, (Jamaica Bay) and in central New Jersey (Barnegat Bay) have also been lost or reduced in size over the last 30 years, and waterbirds have had to abandon a number of nesting sites. In coastal North Carolina, some of the dredged islands in Pamlico Sound and south have suffered extensive erosion the last 30 years as well.
Many waterbird species have shifted from using the Outer Banks barrier beaches to these dredged material islands because of the intense disturbance on the barrier islands from off-road vehicle and recreational access.
By now you might wonder: Where is some good news? Before my retirement, I had written a number of scientific papers concerning waterbird and wetland habitat losses along various coastlines. In the Chesapeake Bay, the prospects for island-building lie largely with various state agencies and the Corps of Engineers. As maintenance of shipping and boating channels is a constant need, there will frequently be the opportunity to either enhance or create new habitat with sands and silts from dredged materials.
The restored Poplar Island site has supported the only state-endangered,common tern population in Maryland’s portion of the Bay over the past decade or so. It also has an increasing population of wading birds, ospreys and ducks.
Another valuable, yet man-made island of great importance to nesting waterbirds is the eastern terminus island of the Hampton Roads Bridge-Tunnel in Virginia. It is home to the largest colony of common terns in Virginia, as well as large royal tern and black skimmer colonies. What had originally been designed as a parking area on the facility has become a waterbird sanctuary. Such sites have been successful for wildlife species because they have received management attention over the years.
Many excellent cooperative joint ventures have developed over the last 20–30 years in the Bay under the umbrella of the Chesapeake Bay Program, among others. No one agency can do all things for all constituent groups.
Where there is enough concern over declining wildlife, I remain hopeful that a consortium of federal, state, academic and private organizations can implement plans to not only mitigate the loss of habitat but restore significant areas of wetlands and upland islands to benefit more than 50 species of migratory birds and other species.
To generate public action and awareness, a wake-up call is sometimes warranted. Perhaps Jennifer Lawrence and Hugh Jackman could co-star in a new movie dramatizing how large flocks of gulls were forced to invade downtown Baltimore or Norfolk as their island sites disappeared — a modern-day version of Hitchcock’s The Birds?