Virginia Coastal Program: 2004 Coastal Grant Project Description and Final Summary

Project Task:

FY2004 Task 11.02

Grantee:

College of William and Mary - Center for Conservation Biology

Project Title:

Seaside Heritage Program- Bird Conservation Projects

Project Description as Proposed:

The barrier island/lagoon system along the seaward margin of the Delmarva Peninsula is one of the most significant bird conservation areas along the Atlantic Coast. The area contains 1) the most pristine chain of barrier islands remaining along the coast that support breeding populations of waterbirds that are regionally significant, and 2) a vast complex of tidal salt marshes that support significant marsh-bird communities.

Several of the avian species of highest conservation concern within the mid-Atlantic region occupy a range of disturbance/successional niches along the barrier islands that are defined by the relationship between beach erosion and beach recovery. Understanding the habitat requirements of these species, as well as, the spatio-temporal patterning of habitat availability is paramount to developing conservation strategies. This subproject will combine historic waterbird surveys with aerial photographs to develop habitat signatures for selected beach-nesting species.

One of the most threatened suites of bird species within the Coastal Plain of northeastern North America depends on high marsh habitat for breeding. This suite includes a number of species that are considered endangered, threatened, species of special concern, or rare within many coastal states. The barrier island/lagoon system along the seaward margin of the Delmarva Peninsula supports some of the most extensive and pristine salt marshes remaining within the mid-Atlantic region. One of the most imminent threats to this community type is the displacement of native vegetation along the marsh-upland ecotone by common reed (Phragmites spp.).

Federal Funding:

$93,612

Project Contact:

Bryan E. Watts, 804.698-4323; bdwatt@wm.edu

Project Status:

Project Completed

Final Product Received:

"Assessing habitat stability for disturbance-prone species by
evaluating landscape dynamics along the Virginia barrier islands" (PDF)

"Potential Impact of Common Reed Expansion on
Threatened High-marsh Bird Communities on the
Seaside: Assessment of Phragmites Invasion of High
Marsh Habitats" (PDF)

Project Summary Provided by Grantee:

Barrier island systems contain some of the most naturally dynamic landscapes on earth. Shoreline stability within these systems often varies dramatically and results from a relatively small set of physical parameters. Along the mid-Atlantic coast, winter storms are the principal source of disturbance and may create landscape pattern by producing a patch mosaic of successional stages. Barrier islands contain unique habitats that are critical to the persistence of many colonial and beach-nesting bird populations. Many of these species occupy a range of disturbance/successional niches that are defined by the relationship between beach erosion (due to storms) and beach recovery (via succession). Over the past 25 years, populations of several waterbird species have declined dramatically within the Virginia barrier island chain. These declines represent not only a reduction in the number of pairs but also a reduction in the distribution of breeding sites. The underlying factors causing these population changes are poorly understood. In order to reverse recent population trends, it is essential that the relative influence of abiotic (e.g. disturbance-driven habitat change) and biotic (e.g. predation) factors be separated within this system.

Temporal and spatial patterns in the morphology of beach habitats were used to quantify the relationship between landscape change and the distribution of avian breeding sites. Seven years (1949-2002) of aerial photos were scanned, orthorectified, and placed in a Geographic Information System. Physical features of the active beach zone were then digitized from processed aerial photographs. Data on active beach area, beach width, distance to nearest wetland, habitat of beach-landward margins were compiled at island and sub-island level and used to compare habitat use patterns of 4 colonial beach nesting species and 2 solitary nesters.

Average values and variance of habitat variables fluccuated widely within and between islands. In general, beach area and beach width varied over time but did not significantly decline over 50 years for most islands. Both colonial and solitary nesting birds used habitats associated with recent storm washover. Birds used wide beaches that were close to mudflats and other wetlands, and that had fewer stable dunes compared to areas not used. The amount of habitat under these conditions was then projected to examine availability over time. In general, the amount of habitat for these disturbance-prone species has fluctuated widely over the last 50 years but has increased in recent years. Based on this evidence, the recent declines of beach-nesting birds are probably better explained by factors other than habitat availability. Nest predation by ground predators, are among the leading alternative factors that have contributed to recent declines.

Disclaimer: This project summary provides the federal dollars initially awarded to the grantee. Due to underexpenditure or reprogramming of grant funds, this figure may change. For more information on the allocation of coastal grant funds, please contact Laura McKay, Virginia Coastal Program Manager, at 804.698.4323 or email: Laura.McKay@deq.virginia.gov

A more detailed Scope of Work for this project is available. Please direct your request for a copy to Virginia.Witmer@deq.virginia.gov

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