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Abstract On the Atlantic and Gulf coasts of the United States, conservation efforts for the American oystercatcher (Haematopus palliatus) commonly focus on improving reproductive success by identifying and managing key threats to nest and chick survival. However, these threats have the potential to change over time. We monitored the reproductive success of American oystercatchers in the Virginia barrier island system, a significant breeding site where annual American oystercatcher productivity has been low since 2016, suggesting evolving drivers of nest and chick survival. We routinely surveyed the nests and broods of breeding pairs from 76 active American oystercatcher territories on Metompkin Island in 2021–2022 and Fisherman Island in 2023. Additionally, we used radio‐telemetry to track one chick per brood (n = 45 chicks) and improve our chances of identifying fate. Using models of age‐specific daily survival rates, we found that the probability of a nest surviving to hatching was high (0.91 ± 0.08 [SD]), relative to the probability of a chick surviving to fledging (0.51 ± 0.14 [SD]), indicating that low chick survival may be limiting reproductive success at sites in Virginia. Overall, American oystercatcher reproductive success was affected by a complicated set of factors, including flooding from tidal inundation and storm surge during the nesting stage, and the threat of predation from a complex predator community during the nesting and brood‐rearing stages. As threats to American oystercatcher reproductive success change in response to climate change and human activities, natural resource managers will need to consider ecosystem‐based management strategies to address those threats, such as habitat restoration to assist behavioral adaptation of nesting American oystercatchers to flooding, and control of threats from both mammalian and non‐mammalian predators.
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Biotic and abiotic factors affecting Atlantic ghost crab (Ocypode quadrata) spatiotemporal activity at an important shorebird nesting site in Virginia
Atlantic ghost crabs (Ocypode quadrata) are predators of beach-nesting shorebird nests and chicks on the United States’ Atlantic and Gulf coasts. Ghost crabs may also disturb birds, altering foraging, habitat use, or nest and brood attendance patterns. Shorebird conservation strategies often involve predator and disturbance management to improve reproductive success, but efforts rarely target ghost crabs. Despite the threat to shorebird reproductive success, ghost crabs are a poorly understood part of the beach ecosystem and additional knowledge about ghost crab habitat selection is needed to inform shorebird conservation. We monitored ghost crab activity, defined as burrow abundance, throughout the shorebird breeding season on Metompkin Island, Virginia, an important breeding site for piping plovers (Charadrius melodus) and American oystercatchers (Haematopus palliatus). We counted burrows at shorebird nests and random locations throughout the breeding season and investigated whether ghost crab activity was greater at nest sites relative to random locations without shorebird nests. While we observed burrows at all nest sites (n= 63 nests), we found that burrow counts were lower at piping plover nests with shell cover, relative to random locations with no shell cover. Ghost crabs may avoid piping plover nest sites due to anti-predator behaviors from incubating adults or differences in microhabitat characteristics selected by piping plovers. We also investigated the effects of habitat type, date, and air temperature on the abundance of ghost crab burrows. We found that while crab burrows were present across the barrier island landscape, there were more burrows in sandy, undisturbed habitats behind the dunes, relative to wave-disturbed beach. Additionally, ghost crab activity increased later in the shorebird breeding season. Understanding when and where ghost crabs are most likely to be active in the landscape can aid decision-making to benefit imperiled shorebird populations.
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- Award ID(s):
- 1832221
- PAR ID:
- 10547749
- Editor(s):
- Romanach, Stephanie S
- Publisher / Repository:
- PLOS
- Date Published:
- Journal Name:
- PLOS ONE
- Volume:
- 19
- Issue:
- 8
- ISSN:
- 1932-6203
- Page Range / eLocation ID:
- e0307821
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1371/journal.pone.0307821
