Piping plovers are small, migratory shorebirds that are found across parts of North America. They nest and raise their young on sandy beaches along the Atlantic coast, Great Lakes, and rivers. Piping plovers are classified as a threatened or endangered species throughout much of their range. There are several major threats facing piping plovers that contribute to their declining populations.
Habitat Loss
One of the biggest threats to piping plovers is habitat loss and degradation. Piping plovers rely on wide, flat, open sandy beaches for nesting and raising young. However, human development along coastlines has eliminated or degraded much of this habitat. Construction of homes, businesses, roads, and recreational facilities has covered and fragmented natural beach habitat.
For example, between 1986 and 2015, 28% of prime piping plover nesting habitat was lost in New Jersey due to shoreline stabilization structures and other human modifications. On Long Island, only 10% of the original beach habitat remains suitable for plovers.
Hard structures built to control beach erosion like seawalls, groins, and jetties prevent natural beach dynamics and accretion that create nesting habitat. Dredging to maintain channels and harbors destroys or alters habitat. Documented habitat loss continues today in piping plover breeding and wintering grounds.
Increased Predation
Another major threat to piping plovers is increased predation on eggs, chicks, and adults. The decline in undisturbed beach habitat has increased exposure to predators like gulls, crows, foxes, raccoons, and cats near human activity.
For example, a 2019 study in Cape Cod, Massachusetts found predation accounted for 85% of nest failures, with gulls responsible for 75% of predated nests. Gulls are abundant near human recreation and development. One New Jersey study found plover nests in disturbed areas were 4 times more likely to fail due to predation.
Predation risk is highest early in incubation. Hatchlings and flightless chicks are also very vulnerable. Adults may risk injury or death defending nests from predators. Predation rates above 29% can destabilize plover populations.
Human Disturbance
Human activities continue to disturb and disrupt piping plover nesting and foraging. Beach recreation, vehicles, pedestrians, fishing, dog walking, boats, and noise can crush eggs, separate chicks, and flush adults from nests or habitat. Forced flight burns crucial energy reserves.
Even well-meaning wildlife watchers and photographers can cause unintended disturbance if they approach plovers too closely.
A 2022 study on Cape Cod beaches found pedestrian traffic reduced plover chick survival by 26%. Chicks in areas with vehicles were only half as likely to survive. Just one or two disturbances per hour can negatively impact plovers.
Rising Sea Levels
Rising sea levels pose an emerging threat to piping plovers by inundating and eroding barrier island beaches where they nest. High tides and storms already destroy some nests and habitat. Projected 1-4 feet of sea level rise this century along the Atlantic coast will further shrink and degrade remaining plover beaches.
For example, a 2016 analysis estimated with 3 feet of sea level rise, 67% of current piping plover habitat in Connecticut would be lost. Vegetation growth in new intertidal zones may also limit habitat suitability for plovers. Rising seas will make protecting wide, natural beaches even more critical.
Climate Change
Climate change beyond sea level rise also threatens piping plovers in multiple ways. Studies suggest climate shifts may disrupt migration timing and increase mismatch with food resources. Hotter summers can increase heat stress and mortality for chicks and eggs in sand habitat.
Modeling indicates that a warming climate will cause plover breeding ranges to shift northward up to hundreds of miles in the coming decades as southern habitats become unsuitable. However, coastal development obstructs northward shifts.
More frequent and intense storms linked to climate change also damage plover nesting beaches through erosion, overwash events, and flooding. Hard shoreline structures meant to protect development impede natural beach recovery after storms.
Population Impacts
All of these threats have contributed to significant declines in piping plover populations over the last century, amplifying their endangered status. Habitat loss has greatly reduced their occupied range and number of breeding pairs.
In the early 1800s, piping plovers were described as abundant breeders on East Coast beaches. By 1985, only 722 breeding pairs remained across the northern Great Plains, Great Lakes, and Atlantic Coast. Their 1986 Endangered Species Act listing aimed to prevent extinction.
Intensive conservation efforts since listing have helped increase Atlantic Coast pairs from just 790 in 1996 to over 2000 pairs today. But populations remain below recovery goals, are still declining in regions like the Great Lakes, and face mounting climate-driven threats.
Conservation Actions Needed
To protect piping plovers, experts recommend focusing habitat and population management on sites with the highest current or potential value, while also maintaining a wide network of smaller but ecologically varied sites across their range.
Specific actions needed include:
- Maximize protection and enlargement of existing high-density breeding sites.
- Secure new undeveloped beach habitats for preservation or restoration.
- Reduce human disturbances through seasonal closures, leashing laws, vehicle limits.
- Minimize predation risks through exclosures, predator management.
- Allow natural beach geological processes to maintain habitat.
- Enhance abandoned habitats through vegetation management, fill sedimentation.
- Monitor and adaptively manage habitats and populations long-term.
- Engage the public through education programs fostering support.
With intensive management and habitat protection, piping plover populations can recover. But active human stewardship will be required to counterbalance continuing development pressures and escalating climate change threats.
Conclusion
In summary, the biggest threats facing piping plovers are habitat loss and degradation, increased predation, human disturbance, rising sea levels, and climate change impacts. These factors have caused severe declines in their population over the last century. Protecting and managing remaining beach habitats will be key to recovering their numbers. But even with conservation efforts, escalating climate-driven threats pose a serious long-term danger to piping plovers and other coastal species relying on sandy beach ecosystems.