Nellie Tsipoura

Shorebird diet during spring migration stopover on Delaware Bay

During spring migration, thousands of shorebirds gather in Delaware Bay at the same time as horseshoc crabs (Linudus polyphemus) are spawning. During their stopover, the birds store enough fuel in the form of fat and muscle protein to complete their migration to the Canadian breeding grounds. We documented the changes in body mass of shorebirds migrating through Delaware Bay and determined how much of the shorebird diet during this period consisted of horseshoc crab eggs. Migrating shorebirds were captured, morphometric measurements taken, and gut samples collected by stomach flushing. Red Knots (Calidris canutus). Ruddy Turnstones (Arenaria interpres), Sanderlings (C. alba), and Semipalmated Sandpipers (C. pusilla) increased their body mass up to 70-80% while staging on Delaware Bay. Horseshoe crab egg membranes constituted the bulk of the gut contents for all species at all collection sites. Polychaete and oligochaete worms were found in substantial concentrations in gut samples collected from shorebirds in certain beaches. Sand and unidentified decomposed material were found in varying amounts in gut samples of all species and locations. Apparent declines in spawning horseshoe crab populations may adversely affect migratory shorebirds.

Metal concentrations in three species of passerine birds breeding in the Hackensack Meadowlands of New Jersey

The New Jersey Meadowlands is an important natural area, a diverse mosaic of wetland habitats positioned within the heavily urbanized NY City Metropolitan area and the NY/NJ Harbor. Persistent contaminants may pose threats to wildlife inhabiting these habitats, affecting reproduction, egg hatchability, nestling survivorship, and neurobehavioral development. Metals of concern in the Meadowlands include arsenic, cadmium, chromium, lead, and mercury. These metals were analyzed in feathers and blood of three passerine birds breeding in wetland habitats, including red-winged blackbirds (Agelaius phoeniceus), marsh wrens (Cistothorus palustris), and tree swallow (Tachycineta bicolor), as well as eggs of the first two species. These widespread species are abundant in wetland habitats across the Meadowlands District, and eat insects and other invertebrates. Lead levels were low in eggs, higher in feathers and very elevated in blood in all species compared to those that have been reported for other bird species. Lead levels were especially high in blood of marsh wren (mean of 0.8 ppm) and swallow (mean of 0.94 ppm, wet weight). Levels of lead in the blood for all three species sampled were higher than the negative impact threshold of 0.4 ppm. Mercury levels, while below the levels considered biologically harmful, were higher in eggs (mean of 0.2, wet weight) and feathers (3.2 ppm, dry weight) of marsh wren from Meadowlands than those seen in other passerines, and even some fish-eating birds. Furthermore, unhatched wren eggs had higher mercury levels (0.3 ppm, wet weight) than eggs randomly selected before hatch (0.18 ppm, wet weight). Blood tissue levels of mercury were low in all three species (mean of less than 0.035 ppm, wet weight). Chromium levels were relatively high in eggs and in blood, but lower in feathers when compared to those reported in the literature. Cadmium and arsenic levels were generally low for all tissues and in all species studied compared to those measured in other studies. Finally, all metal levels for tree swallow tissues in our study were much lower than those reported previously for this species in the Meadowlands District.

Lead, mercury, cadmium, chromium, and arsenic levels in eggs, feathers, and tissues of Canada geese of the New Jersey Meadowlands

The New Jersey Meadowlands are located within the heavily urbanized New York/New Jersey Harbor Estuary and have been subject to contamination due to effluent and runoff from industry, traffic, and homes along the Hackensack River and nearby waterways. These extensive wetlands, though heavily impacted by development and pollution, support a wide array of bird and other wildlife species. Persistent contaminants may pose threats to birds in these habitats, affecting reproduction, egg hatchability, nestling survival, and neurobehavioral development. Metals of concern in the Meadowlands include arsenic, cadmium, chromium, lead, and mercury. These metals were analyzed in eggs, feathers, muscle, and liver of Canada geese (Branta canadensis) breeding in four wetland sites. We sampled geese collected during control culling (n=26) and collected eggs from goose nests (n=34). Levels of arsenic were below the minimum quantification level (MQL) in most samples, and cadmium and mercury were low in all tissues sampled. Chromium levels were high in feather samples. Mercury levels in eggs of Canada geese, an almost exclusively herbivorous species, were lower (mean ±SE 4.29±0.30μg/g wet weight) than in eggs of omnivorous mallards (Anas platyrhynchos), and insectivorous red-winged blackbirds (Agelaius phoeniceus) and marsh wrens (Cistothorus palustris) from the Meadowlands, consistent with trophic level differences. However, lead levels were higher in the goose eggs (161±36.7ng/g) than in the other species. Geese also had higher levels of lead in feathers (1910±386ng/g) than those seen in Meadowlands passerines. By contrast, muscle and liver lead levels were within the range reported in waterfowl elsewhere, possibly a reflection of metal sequestration in eggs and feathers. Elevated lead levels may be the result of sediment ingestion or ingestion of lead shot and sinkers. Finally, lead levels in goose liver (249±44.7ng/g) and eggs (161±36.7ng/g) may pose a risk if consumed frequently by humans. Mill Creek, the site with the most documented prior contamination, had significantly elevated cadmium, chromium, mercury, and lead in goose tissues.

Corticosterone and growth hormone levels in shorebirds during spring and fall migration stopover.

Large numbers of shorebirds stop over at Delaware Bay during spring migration and undergo major mass increases within a two- to three-week period. We studied plasma levels of corticosterone and growth hormone in three species of migrants that use this site, sanderlings, Calidris alba, semipalmated plovers, Charadrius semipalmatus, and semipalmated sandpipers, Calidris pusilla. Semipalmated sandpipers were also studied at a fall migration stopover in Manomet, Massachusetts. These two hormones were chosen because they modulate the physiological processes of lipogenesis/lipolysis and promote increased feeding in birds. The stress response was not suppressed in the shorebirds studied, and plasma levels of corticosterone were elevated compared to other studies. We believe that the high levels of corticosterone relate to the rapid fat deposition that takes place at this stop-over site. There was a significant negative correlation between plasma growth hormone and body mass, indicating the lipolytic effects of the growth hormone. Because the lighter birds are recent arrivals to Delaware Bay they may have elevated plasma growth because of fat breakdown during flight to this stop-over site. High levels of growth hormone may also result in protein synthesis, replenishing tissues broken down during the previous migratory bout. J. Exp. Zool. 284:645-651, 1999.

Metal levels in horseshoe crabs (Limulus polyphemus) from Maine to Florida

There is considerable concern for the health of spawning populations of horseshoe crabs (Limulus polyphemus) along the east coast of North America because of an increase in the harvest, an apparent decrease in population levels, and the dependence of migrating shorebirds on a superabundant supply of horseshoe crab eggs during their migratory stopover on Delaware Bay. In addition to overfishing, population declines could be caused or recovery slowed, by pollution. In this paper, we examine the levels of metals (arsenic, cadmium, chromium, lead, manganese, mercury, and selenium) in the eggs, leg muscle, and apodeme of 100 horseshoe crabs collected at nine sites from Maine to Florida. Arsenic levels were the highest, followed by manganese and selenium, while levels for the other metals averaged below 100ppb for most tissues. Arsenic and mercury levels were highest in the leg muscle; cadmium, lead, manganese, and selenium levels were highest in eggs; and chromium levels were highest in the apodeme. There were significant geographical differences for all metals in all three tissues. No one geographical site had the highest levels of more than two metals. Arsenic, with the highest levels overall, was highest in Florida in all the three tissues. Manganese levels were highest in Massachusetts for eggs and apodeme, but not leg, which was highest in Port Jefferson, New York. Selenium was highest in apodeme from Florida, and in eggs and leg muscle from Prime Hook, Delaware. The patterns among locations and tissues were not as clear for the other metals because the levels generally averaged below 100ppb. The levels of contaminants found in horseshoe crabs, with the possible exceptions of arsenic in Florida, and mercury from Barnegat Bay and Prime Hook, were below those known to cause adverse effects in the crabs themselves or in organisms that consume them or their eggs. Our results indicate that site-specific data are essential for managers to evaluate the potential threat from contaminants to both the horseshoe crabs and those that consume them.

Mercury, Lead, Cadmium, Arsenic, Chromium and Selenium in Feathers of Shorebirds during Migrating through Delaware Bay, New Jersey: Comparing the 1990s and 2011/2012

Understanding temporal changes in contaminant levels in coastal environments requires comparing levels of contaminants from the same species from different time periods, particularly if species are declining. Several species of shorebirds migrating through Delaware Bay have declined from the 1980s to the present. To evaluate some contaminants as cause for the declines, we examine levels of mercury, lead, cadmium, arsenic, chromium and selenium in feathers of red knot (Calidris canutus, N = 46 individuals), semipalmated sandpiper (Calidris pusilla, N = 70) and sanderling (Calidris alba, N = 32) migrating through Delaware Bay, New Jersey, USA, from 1991 to 1992 (N = 40), 1995 (N = 28), and 2011–2012 (N = 80) to determine if levels have changed. We found: (1) arsenic, chromium, and lead increased in red knot and decreased in semipalmated sandpiper; (2) cadmium decreased in semipalmated sandpipers; (3) mercury decreased in red knot and sanderlings; (4) selenium decreased in red knot and increased in semipalmated sandpipers. In 2011/2012 there were significant interspecific differences for arsenic, mercury and selenium. Except for selenium, the element levels were well below levels reported for feathers of other species. The levels in feathers in red knots, sanderling, and semipalmated sandpipers from Delaware Bay in 2011/2012 were well below levels in feathers that are associated with effect levels, except for selenium. Selenium levels ranged from 3.0 µg·g−1 dry weight to 5.8 µg·g−1 (semipalmated sandpiper), within the range known to cause adverse effects, suggesting the need for further examination of selenium levels in birds. The levels of all elements were well below those reported for other marine species, except for selenium, which was near levels suggesting possible toxic effects.

Ecological Considerations for Evaluating Current Risk and Designing Long-Term Stewardship on Department of Energy Lands

In this paper, we discuss methods to integrate ecological resources, ecosystem services, risk, and the transition to long-term stewardship on Department of Energy lands. Three types of information are required about ecological resources before decisions can be made about remediation, site transitions, and long-term stewardship: (1) the ecological resources and ecosystem functions (such as productivity) present on site and their spatial pattern, (2) the ecosystem services these resources provide to people, and (3) the risks from the interactions between people and these ecosystems. Once the ecological resources and ecosystem services are evaluated, then decisions about future land use, preservation, conservation, or protection of ecological resources within a designated land use can be implemented. Long-term stewardship requires both ecosystem protection in terms of biological resources and ecosystem function as well as biomonitoring to ensure minimal radiological or chemical risk and to inform future management. In some cases, protection of ecological resources may be preferable to cleanup that is physically disruptive, provided land use designation is consistent with ecological protection. In such instances, less site cleanup can prove preferable to more.

Metals in tissues of migrant semipalmated sandpipers (Calidris pusilla) from Delaware Bay, New Jersey.

There is an abundance of field data on levels of metals for feathers in a variety of birds, but relatively few data for tissues, especially for migrant species from one location. In this paper we examine the levels of arsenic, cadmium, chromium, lead, manganese, mercury and selenium in muscle, liver, brain, fat and breast feathers from migrant semipalmated sandpipers (Calidris pusilla) collected from Delaware Bay, New Jersey. Our primary objectives were to (1) examine variation as a function of tissue, (2) determine the relationship of metal levels among tissues, and (3) determine the selenium:mercury molar ratio in different tissues since selenium is thought to protect against mercury toxicity. We were also interested in whether the large physiological changes that occur while shorebirds are on Delaware Bay (e.g. large weight gains in 2-3 weeks) affected metal levels, especially in the brain. There were significant differences among tissues for all metals. The brain had the lowest levels of arsenic and cadmium, and was tied for the lowest levels of all other metals except lead and selenium. Correlations among metals in tissues were varied, with mercury levels being positively correlated for muscle and brain, and for liver and breast feathers. Weights vary among individuals at the Delaware Bay stopover, as they arrive light, and gain weight prior to migration north. Bird weight and levels of arsenic, cadmium, and selenium in the brain were negatively correlated, while they were positively correlated for lead. There was no positive correlation for mercury in the brain as a function of body weight. The selenium:mercury molar ratio varied significantly among tissues, with brain (ratio of 141) and fat having the highest ratios, and liver and breast feathers having the lowest. In all cases, the ratio was above 21, suggesting the potential for amelioration of mercury toxicity.

Metals in horseshoe crab eggs from Delaware Bay, USA: temporal patterns from 1993 to 2012

The health of horseshoe crab (Limulus polyphemus) eggs is important not only to maintain horseshoe crab populations, but because they are a resource for higher trophic levels, such as fish and shorebirds. We examined the concentrations of arsenic, cadmium, chromium, lead, manganese, mercury, and selenium in the eggs of horseshoe crabs from Delaware Bay (between New Jersey and Delaware, USA) in 1993, 1994, 1995, 1999, 2000, and 2012 to determine if there were significant temporal changes and if levels appear to pose a health risk to the crabs themselves, or to predators that consume them. All metal levels declined in horseshoe crab eggs between 1994 and 2012, although the declines were much less consistent for lead and chromium than that for mercury and cadmium. Levels of contaminants found in these eggs are well below those known to cause adverse effects in the crabs themselves or to organisms that consume them, such as migrating shorebirds.

Stakeholder contributions to assessment, monitoring, and conservation of threatened species: black skimmer and red knot as case studies

Stakeholder contributions to conservation projects often occur during the problem formulation stage, yet the role of stakeholders throughout the process is seldom considered. We examine the diversity of state and federal agencies, conservation organizations, other non-governmental organizations, environmental justice communities, consultants, industry, and the general public in the conservation of red knot (Calidris canutus rufa) and black skimmer (Rynchops niger) in New Jersey. We suggest that (1) governmental agencies provide the legal, regulatory, and management framework, but it is often the universities, conservation organizations, consultants, and the public that conduct the research and perform activities that lead to increased research and conservation efforts; (2) departments within agencies may have conflicting mandates, making it difficult to resolve differences in actions; (3) there is often conflict among and within state agencies and conservation organizations about roles and priorities; and (4) the role of the public is critical to ongoing research and conservation efforts. Identification of all the relevant stakeholders is necessary to recognizing competing claims, identifying the threats, deciding how to manage the threats, and enhancing population viability. Conflicts occur even within an agency when one department oversees science and protection of populations and another oversees and fosters an industry (aquaculture or fisheries, or permits for off-road vehicles). Conflicts also occur between resource agencies, industry, and conservation organizations. Recognizing the different stakeholders and their mandates, and encouraging participation in the process, leads to a better understanding of the threats, risks, and possible solutions when conflicts arise. Tracking stakeholder viewpoints and actions can lead to increased involvement and conflict resolution.