Ecology and Vulnerability

Piping Plover

Background
The piping plover is an iconic shorebird along Atlantic Coast beaches.  Although frequently associated with these coastal beaches, among the three recognized breeding populations, two are actually found inland.  In addition to the Atlantic Coast population, which extends from Canada to North Carolina, populations are found on the Great Plains extending from Nebraska through Alberta, Canada and along the shorelines of Lakes Michigan, Superior, and Huron ¹.  All of these populations are short distance migrants that winter along the Gulf or southern Atlantic Coast and in the Bahamas ¹.

In Massachusetts, piping plovers arrive on breeding grounds in late March and April ².  The birds are found on wide, barren, sandy beaches, and will nest on sparsely vegetated beaches above the high tide line.  Most will leave Massachusetts for wintering grounds by late August.

Increased human populations and intense development pressure associated with coastal areas have led to a decline in piping plover populations ³.  The species was federally listed as threatened in 1986 when only 790 pairs remained ⁴.  Management efforts in the years since have resulted in population increases so that there were approximately 8,000 individuals globally in 2006 ⁵.

Climate Impacts
Climate change is expected to result in rising sea levels due to the melting of glacial ice and thermal expansion of water ⁶.  Sea levels have been rising at an accelerated rate for at least the past 50 years in New England, exceeding average global rates ^7,8.  In addition, there is an expected increase in the frequency of severe storms along with higher storm surges, which is likely to result in increased inundation of tidal areas during storms ^9,10.  The northeast in particular has experienced approximately one foot of sea-level rise since 1900, and is projected to experience anywhere between 1.5 to 6 feet of additional sea-level rise over the next century ^8,11. 

Habitat for piping plovers has the potential to migrate as sea level rises and beaches are pushed inland ^3,13.  However, the extent to which this can happen depends on whether the area inland of beaches is developed, as beachfront development does not leave room for beaches to migrate inland and can instead result in 'coastal squeezing' and loss of habitat ^3,12. Piping plover habitat on barrier islands of Suffolk County, NY  was projected to decline by as much as 41% with 1.6 feet of sea level rise when habitats were unable to migrate (static response). However, their habitat was projected to increase by as much as 15% with increasing sea levels if these barrier islands respond dynamically by migrating. However, when development is considered, this expansion in habitat can be reduced by 12% ³. Some actions designed to mitigate climate change impacts, such as building sea walls, can also prevent habitat migration ¹².  Along with sea level rise, human populations of coastal communities are anticipated to increase³, putting further pressure on available habitat.  Strategies to reduce conflict between development and conservation of piping plover habitat in the face of climate change have been recommended, including controversial measures such as zoning regulations and closing of public access ^3,5.

In addition to loss of habitat, increasing occurrence of severe storms has the potential to directly impact piping plovers through flooding of nests ³.  Such storms may result in increased nest abandonment and bird mortality. The combined effects of sea level rise and coastal storms could be severe. Storm surge from a major hurricane under a 4.9 ft sea level rise was projected to flood over 95% of plover habitat in Suffolk County, NY ³. In some cases, storms can create or enhance habitat while resulting in localized losses elsewhere. After storm events, piping plover populations can increase where overwash areas are created. Where barrier islands are allowed to migrate in response to SLR and storms, the occupation of new inlets and beaches created by overwash events is also possible ¹⁴.