Tidal Exchange: Winter 2005
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Winter 2005 Issue
Harbor Estuary News Contents
NYC Audubon’s 2004 Harbor Herons Shore Monitoring Program
Tracking the Harbor Herons from Nesting Sites to Foraging Grounds
Little Hell Gate Wetlands at Randall’s Island Park, New York City
HEP Priority Restoration Site LI15 (Click Here)
Eric Rothstein and Anne K. Wilson
Issues Affecting Winter Flounder Biology in the Northeast (Click Here)
Transition of Habitat Work Group Chair (Click Here)
NYC Audubon’s 2004 Harbor Herons Shore Monitoring Program
Tracking the Harbor Herons from Nesting Sites to Foraging Grounds back to top
The most recent expansion of long-legged wading bird populations in the New York City area dates back to the mid to late 1970s. Herons, egrets, and ibis - known collectively as the Harbor Herons - first settled near the western shore of Staten Island, on the uninhabited islands of Shooters, Pralls, and Isle of Meadows. Each summer during the birds’ breeding season, these islands were transformed into noisy colonies. Shortly after the proliferation of the Harbor Herons, New York City Audubon began conducting annual nesting surveys to monitor their populations and track the location of their colonies. Although the birds do not currently nest on Shooters, Pralls, and Isle of Meadows, a number of the Harbor Estuary’s other islands do have thriving colonies. The 2004 nesting survey, headed by NYC Audubon ornithologist-consultant Paul Kerlinger, PhD, counted approximately 1,700 pairs of wading birds nesting in
seven colonies throughout the
NY-NJ Harbor Estuary.
The Harbor Herons’ arrival in New York Harbor was an important event. These magnificent creatures were both easy to spot because of their large size and beautiful to look at. In fact, some consider them to be a “charismatic species,” similar to elephants and lions in Africa’s Serengeti. These birds are also important for other reasons. Since they feed on the Estuary’s fish and invertebrates, their success depends on the improved environmental quality of the Harbor and its watershed. In this sense they are an “indicator species,” telling us something about the quality of our environment.
It is the combination of these birds’ beauty, vulnerability, and usefulness as an indicator species that has made them the focus of many different conservation and research programs. One such program is NYC Audubon’s Harbor Herons Project, which has conducted the aforementioned annual nesting surveys since 1982. A more recent initiative within this Project is the Harbor Herons Shore Monitoring Program, funded by a generous grant from New York City Environmental Fund.
The Harbor Herons Shore Monitoring Program, now in its third year, aims to identify and protect the foraging grounds of the Harbor Herons. But given that the birds can fly more than 10 miles in search of food, the main challenge becomes finding these areas which could be scattered all over the Tri-State region. One could simply make a list of all the areas in which wading birds were known to feed, but this method would not tell us whether the birds were residents of the Harbor Estuary. Satellite telemetry could also be used to track the Harbor Herons’ movement, but this technology is very expensive.
Because these other techniques were not feasible, NYC Audubon developed its own method for locating the Harbor Herons’ foraging grounds. First, identify and chart the flight lines of the Harbor Herons as they leave and enter their island-colonies. Second, use these flight lines to lead us to the foraging grounds. The flight lines are identified by monitoring the birds from shore locations opposite the island-colonies.
During the 2004 breeding season 2,811 birds were observed flying to or from the island-colonies of Brother Islands (North and South Brother) in the Bronx, Hoffman Island off of Staten Island, and Canarsie Pol in Jamaica Bay. Evening and morning monitoring was conducted by a group of dedicated NYC Audubon volunteers using spotting scopes and binoculars to identify the various wading birds. The main species observed were Black-crowned Night-heron, Great egret, Snowy egret, and Glossy ibis.
As the data accumulated, it was possible to chart circular graphs showing the percentage of birds observed flying in each of the 8 major compass directions at each island-colony. These circular graphs showed most of the birds flying in and out of the colonies using one main direction. For instance, at the Brother Islands we found about 80 percent of the birds flying in a southwesterly direction (when flying out of the colony). The graphs also revealed interesting differences with respect to the flight patterns of each species (see Figures A & B). While Great and Snowy egrets were mostly flying in one direction in and out of the colony at the Brother Islands, Black-crowned Night-herons used other flight directions.
The circular graphs were also used to chart the flight lines in each colony (see Figure C).
Again, the Brother Islands colony proved to be an interesting case. By combining this season’s data with last year’s, it became apparent that many of the birds were flying southwest from the colony, and then taking a turn westwards towards Manhattan. We knew about this “turn” from work done in 2003 by volunteers led by Andy Bernick – a PhD candidate at CUNY’s Graduate Center. Assuming the birds did not forage in Manhattan, we continued drawing the flight line towards New Jersey and were not surprised to find that this projected line lead directly to the 7,000-acre NJ Meadowlands. Based on this information, we theorized that most of the Brother Island birds were flying to this site. Flight lines for the Hoffman and Canarsie Pol colonies were projected in a similar fashion.
This season’s experience was like piecing together a grand puzzle, with each piece shedding more light on the birds’ foraging locations. Towards the end of the season we conducted various field surveys in some of the areas indicated by the projected flight lines, including the NJ Meadowlands. Visiting this area we spotted, quite by accident, a roosting colony numbering about 85 egrets. Were these the same egrets that nested on Brother Islands? The answer seemed to be yes. Not only because the flight lines suggested each colony was using its own separate foraging grounds, but also because no ibis were spotted during the NJ Meadowlands field survey. We would not expect ibis to come over from the Brother Islands (since no ibis were nesting there), but ibis from the nearby Hoffman colony might have foraged in the Meadowlands. The fact that they didn’t supports the notion that Hoffman birds foraged in other regions, while Brother Island birds foraged in the NJ Meadowlands.
While certain questions remain, this season has been a great success. We came closer to understanding where the Harbor Herons forage. Finding these birds in the NJ Meadowlands, for instance, underscored the goal of the Harbor Herons Project – the need to preserve the birds’ foraging grounds as well as their nesting sites. Like a pair of shoes – where one is worthless without the other – only the preservation of both habitats will ensure that the Harbor Herons continue to call this place home. NYC Audubon’s Harbor Herons Shore Monitoring Program was successful in its other goal as well, which is to create a community of informed stewards to advocate on behalf of wading birds and their nesting and foraging sites in the Harbor Estuary. I wish to thank all the NYC Audubon volunteers for their dedication and hard work.
The Shore Monitoring Program will continue this summer. To learn more about volunteer opportunities, call NYC Audubon at (212) 691-7483 or visit www.nycaudubon.org.
Yigal Gelb was the Program Coordinator of NYC Audubon’s Harbor Herons Shore Monitoring Program in 2004, and is currently the Program Director for NYC Audubon. Mr. Gelb is in the process of writing a paper to be published in a peer reviewed journal: Inter-Colony Differences in Wading Bird Flight Patterns in New York Harbor.
Little Hell Gate Wetlands at Randall’s Island Park, New York City
HEP Priority Restoration Site LI15 back to top
Eric Rothstein and Anne K. Wilson
Randall’s Island comprises a 480-acre New York City park located in the East River at the intersection of the Triborough Bridge linking Manhattan, Queens, and the Bronx. The Island offers a rare mix of recreational amenities and natural habitats adjacent to some of the City’s most under-resourced neighborhoods, including the South Bronx and East Harlem. Unfortunately, the Island’s wetlands and natural areas are degraded with garbage and construction debris, and its seawalls are crumbling and unsafe. To fulfill its vision of the Island as an important public and natural resource, the New York City Department of Parks and Recreation Natural Resources Group (NRG), in public-private partnership with the Randall’s Island Sports Foundation (RISF), is undertaking a wetlands restoration project at Little Hell Gate Wetlands (HEP Restoration Site LI15).
Little Hell Gate Inlet - situated on the western edge of the landmass, where two islands (Randall’s and Wards) were once separated by water - offers remarkable restoration potential, with associated benefits for water quality, habitat and environmental education. This site is one of the last remaining areas of undeveloped, un-bulkheaded waterfront on Randall’s Island. Plans include restoration of a total of 5.25 acres, including 3.25 acres of salt marsh and 2 acres of freshwater wetlands.
To restore salt marsh conditions at Little Hell Gate, approximately 30,000 cubic yards of fill will be removed. The site will then be regraded with clean sand and planted with salt marsh grasses. Spartina alterniflora will be planted over 3 acres of low marsh, and Spartina patens and Panicum virgatum will be planted as high marsh/upland transition habitat.
Spartina alterniflora has an unparalleled ability to take up heavy metals and petroleum byproducts, improving water quality and creating habitat conditions for ribbed mussels and fiddler crabs. In addition, the restored site will provide foraging grounds for the wading birds that breed on nearby North and South Brother Islands (HEP Acquisition Site LI1) - part of the Harbor Herons Complex and designated an Important Bird Area by the National Audubon Society and New York State.
Excavation in the freshwater wetlands area involves removal of fill and construction debris from a two-acre area currently dominated by invasive plant communities such as Artemesia sp. and Phragmites australis. Planting plugs will provide rapid root growth to stabilize soils and prevent erosion.
The natural presence of surface water and upland buffers adjacent to the freshwater restoration site offers enormous potential for wildlife habitat. Plantings will include native herbaceous, shrub, and tree species. Rare in New York City, native plant-dominated wetlands are critical breeding areas for a variety of organisms, including several species of dragonflies and damselflies that require slow-moving water to complete their breeding cycle. These restored wetlands will also provide excellent breeding and migratory habitat for birds such as red-winged blackbirds, marsh wrens, common yellowthroats, swamp sparrows, and green herons.
By restoring tidal flow and salt marsh grasses, this project will reduce nonpoint source pollution and nitrogen inputs into the East River and Long Island Sound, improving the health of a system that experiences severe hypoxia. Additionally, restoring two acres of freshwater wetlands will absorb and filter nonpoint source pollution from the Island’s parking lots and roads before runoff reaches the East River.
Funding for the restoration project's design and construction documents has been provided by the New York State Department of State (NYSDOS) Division of Coastal Resources through the Environmental Protection Fund, and is matched locally by the New York City Council. The New York State Department of Environmental Conservation is providing construction funding through the Clean Air/Clean Water Bond Act, matched by the New York City Department of Environmental Protection and managed by NYSDOS.
Environmental restoration work is just one component of RISF’s Management, Restoration and Development Plan (1999) for the Island, developed in collaboration with local community groups and City leadership. The Plan guides all development and stewardship activities in the Park. In addition to wetlands restoration, new Park recreational facilities are being built, including the $42 million Icahn Stadium - an Olympic-caliber track and field facility opening in spring 2005; a 20-court Tennis Center; and over 60 new and improved athletic fields. Also in keeping with RISF’s Plan, an Island-wide pedestrian and bicycle pathway system will be built to provide easy access to the waterfront and the Inlet, facilitating bird-watching, fishing, and the enjoyment of scenic views.
The first pathway section, to be constructed in spring 2005, is fully funded through grants from NYSDOS, New York State Department of Transportation (NYSDOT), New York State Office of Parks, Recreation and Historic Preservation, the Office of the Manhattan Borough President and the New York City Council. This pathway will lead visitors from Manhattan directly to Little Hell Gate Inlet’s restored wetlands, where an educational boardwalk and overlook has been built with funding from NYSDOT and City Council Member Philip Reed. This boardwalk is especially geared toward participants in RISF’s free environmental education programs for local public schools and community-based organizations in East Harlem and the South Bronx.
Finally, RISF is working to expand on these habitat and public access improvements with another major capital project - a Visitor and Nature Center to house environmental programs to be constructed at a reclaimed building adjacent to the Inlet just south of the restoration site. The restored habitats of Little Hell Gate Inlet thus serve as a nexus of waterfront exploration, education and appreciation in this remarkable urban park.
Eric Rothstein is a Project Manager and Hydrologist for The City of New York Department of Parks and Recreation Natural Resources Group (NRG). NRG, founded in 1984, implements management programs for the protection, acquisition, and restoration of the City’s vast natural resources. NRG inventories flora, fauna, soils, hydrology, and generates plans that guide management of the City’s 28,000-acre park system.
Anne K. Wilson is Director of Planning and Development at the Randall’s Island Sports Foundation (RISF), founded in 1992 as a public-private partnership with the City of New York Department of Parks and Recreation. The Foundation, in conjunction with City leadership, works to realize the unique potential of Randall’s Island Park, by developing sports and recreational facilities, restoring its vast natural environment, reclaiming and maintaining parkland, and sponsoring community-linked programs for the children of New York City. For more information see www.risf.org.
Issues Affecting Winter Flounder Biology in the Northeast back to top
Winter flounder (Pseudoplueronectes americanus) constitutes an important fishery among anglers and commercial fishers in the northeast each winter. As the name suggests, these fish prefer cooler waters, migrating inshore during winter and moving off shore as the waters warm up in late spring. This estuarine-dependent species spawns in the inshore estuaries, where larvae settle to the bottom 5-6 weeks after hatching. The larvae possess a traditional pisciform body shape when first hatched, but quickly metamorphose into the asymmetrical form characteristic of flatfish. Winter flounder can grow up to 25” long and are believed to live up to 12 years.
The geographic range of winter flounder is from Labrador to Georgia. The Atlantic States Marine Fisheries Commission (ASMFC) and the Mid-Atlantic Fisheries Management Council manage this species jointly. For management purposes, winter flounder stocks on the northeastern seaboard are divided into three groupings — Gulf of Maine, Southern New England-Mid-Atlantic, and Georges Banks (federal waters). Recently, genetic research suggests that stocks may be more discrete than previously believed, and sub-populations may exist within these geographic boundaries.
The news isn’t good for this species; the most recent stock assessment indicates that stocks are at a fraction of the historic level and continue to be overfished. Biomass has declined by more than half (70-30 million lbs) over two decades (1981-2001) and the response to management has been mixed in the various regions. Although the Gulf of Maine has shown promising signs of recovery, this has not been the case in the Mid-Atlantic region. This fact has prompted the agencies to undertake efforts to revise and update the goals of their winter flounder fisheries management plan.
Research in recent years demonstrates the potential role of the environment as it affects the general health status of winter flounder stocks. A growing concern raised among anglers is the effect of habitat loss and degradation on juvenile stages. Young-of the-year fish (y-o-y) spend their first winter inshore among beds of submerged aquatic vegetation, which helps them hide from predators. Research suggests that vegetation type can enhance survivorship, with eelgrass beds (Zostera marina) showing lower mortality rates than sea lettuce (Ulva lactuta) or unvegetated sand. The winter flounder’s vulnerability depends on several factors, however, including its activity level and the vision of its predators’ optic range (vision), which varies by species. Predators include sand shrimp, striped bass, bluefish, summer flounder, green crab, and American lobster.
Previously, discussions blamed nuclear plants for the noticeable decline in this species; however, there isn’t sufficient evidence to support these claims. Researchers believe that global warming is more likely to have impacts on winter flounder populations, and survival rates are expected to be lower after a warm winter. In fact, it is believed that warm waters give predators the advantage, causing them to appear in the water column earlier in the season when y-o-y are still settling to the bottom.
Pollution is another factor that has undermined these stocks and evidence suggests that winter flounder are sensitive to contamination. The results of one study showed that y-o-y held on contaminated sediment experienced significantly higher mortality.
Other evidence supports claims of the negative impacts that contaminated sediments have on winter flounder biology. Jamaica Bay receives millions of gallons of effluent each day, and these sediments contain high levels of estrogenic mimics that are believed to cause endocrine disruption. When compared to an eastern Long Island reference site (Shinnecock Bay), fish samples collected in Jamaica Bay showed a significant difference in sex ratios, in favor of females, and unusual levels of female hormones. These biases in sex ratios can affect the stocks’ ability to recover in the long term.
Several diseases have been documented in winter flounder in recent years. Gulf of Maine stocks have been suffering from skin ulcers that appear to be more pronounced in late spring. Researchers haven’t yet pinpointed the source of these infections; although the ulcers contain high levels of bacteria, this is not considered to be the primary source. Fin rot, a disease characterized by fin loss and muscular degeneration, has been reported for stocks in Connecticut (New Haven). Although the etiology of fin rot is still unknown, it is believed to be caused by toxins that are concentrated through the food chain.
Although no single factor has been identified as the primary cause of decline, there is agreement that winter flounder stocks require attention. To respond to the continued decline, the Atlantic States Marine Fisheries Commission began a series of public hearings in fall 2004 to review the winter flounder fisheries management plan. For more information, contact the ASMFC or visit www.asmfc.org.
This article was compiled by a review of literature and represents research results from several institutions. For more information on flatfish biology research visit www.nefsc.noaa.gov/publications/crd/crd0413.
Antoinette Clemetson is the Marine District Fisheries Specialist for
New York Sea Grant.
Transition of Habitat Work Group Chair back to top
As many of you know, Nancy Welsh, of the New York State Department of State, has very skillfully chaired the Habitat Work Group (HWG) of the New York-New Jersey Harbor & Estuary Program (HEP) for nearly three years. She has championed the OASIS interactive habitat mapping effort, overseen the nomination, review and addition of numerous sites to the HEP Acquisition and Restoration list, encouraged us all think long and hard about improving wetland mitigation policy, and has been an active proponent of restoration work. Unfortunately for HEP, Nancy has too many other obligations and some months ago, requested that a new chair be sought. I would like to thank Nancy Welsh for her tireless work and trust that she will continue to interact with us as her schedule permits.
After a long search for a replacement, I would like to welcome Alex Brash as the new Chair of the Habitat Work Group. Alex is the Senior Director of the Northeast Region of the National Parks Conservation Association (NPCA). Many of you know Alex from his role at New York City Department of Parks & Recreation (Parks). During his time there, he was the Director of the Management Planning Division; Chief of the Urban Park Service; and Chief of the Natural Resources Group. In this latter position he was responsible for overseeing large scale environmental restoration projects, acquiring parkland for preservation and habitat restoration, and for formulating Park’s environmental policies. He also conceptualized and oversaw its first program to re-introduce extirpated plants and animals to New York City and built a series of partnerships and led a major fund-raising campaign for Park’s environmental efforts. While Alex’s official job at NPCA initially is to develop support for the National Park units in the metropolitan area, he is anxious to lead HEP’s Habitat Work Group in its efforts on non-NPS habitat issues as well.
- Bob Nyman, HEP Director