Returning the Birds to Faulkner's Woods.
The Mississippi Alluvial Valley Migratory Bird Initiative was launched to identify habitat restoration needs and population goals for neotropical migrants, waterfowl, and shorebirds. These three groups of birds have partially overlapping habitat needs and were used as the basis for an ecosystem scale restoration plan for the Mississippi Alluvial Valley. Neotropical migrants and other birds breed in the remaining forests, waterfowl winter in the forests and agricultural fields, and shorebirds feed and rest on mudflats during spring and fall migration.
Three organizations collaborated to accomplish this daunting planning task: the Southeast Working Group of Partners In Flight, the Lower Mississippi Valley Joint Venture of the North American Waterfowl Management Plan, and the Western Hemisphere Shorebird Reserve Network. Each organization brought its expertise to the table and blended it with the contributions of the others to develop a quantified, site-specific habitat restoration/protection plan that should meet the long-term needs of all three bird groups. The development of a geographic information system for the entire Mississippi Alluvial Valley by the Lower Mississippi Valley Joint Venture was critical to the success of this project.
The goal for neotropical migrants and other forest breeding birds (70 total species) is to establish self-sustaining breeding populations for all species. Using information from the technical literature and calculating a theoretical genetically viable population level, we set a goal of at least 500 breeding pairs for each targeted forest patch, which we refer to as Bird Conservation Areas. We multiplied this goal by the average breeding density for each species and added an adjustment factor to overcome the adverse effects of the severe forest fragmentation in the Mississippi Alluvial Valley. To accommodate different associations of bird species, we identified three target Bird Conservation Area sizes: 4,000-8,000 ha (10,000-20,000 acres), 8,000-40,000 ha (20,000-100,000 acres), and greater than 40,000 ha. Although these results remain untested, forest patches of these sizes should support self-sustaining populations of all the forest breeding bird species in the Mississippi Alluvial Valley. Ninety Bird Conservation Areas were located throughout the Mississippi Alluvial Valley, with approximately 400,000 hectares (1 million acres) of reforestation required to meet these goals. The locations of Bird Conservation Areas were based on the existing forest, reforestation potential, flood frequency, and public lands. Substantial cooperation from private landowners will be essential to achieve these reforestation and breeding bird population goals.
For waterfowl, our goal is to provide enough habitat in the Mississippi Alluvial Valley to support 4.3 million wintering ducks and one million wintering geese. We assumed that food was the limiting factor and calculated food availability and caloric value for each of the three primary foraging habitats: bottomland hardwood forests, moist soil sites, and agricultural fields. By applying waterfowl energy needs to these data, we estimated that 285,000 hectares (712,500 acres) of foraging habitat are needed to support the population goals for wintering waterfowl in the Mississippi Alluvial Valley. This goal is divided among the States on the basis of habitat type and public or private ownership. For public lands (State and Federal), the habitat goals are distributed among individual management areas so that each management area has its own waterfowl habitat target and managers are able to see how their actions contribute to larger ecosystem goals.
The waterfowl population target, developed as part of the national planning effort for the North American Waterfowl Management Plan, was based on 50 years of research and population monitoring. For shorebirds, we had much less research and almost no population data to use in developing population goals. As with waterfowl, food was assumed to be the limiting factor, and we set a goal of supporting 0.5 million shorebirds during their southward migration. The spring migration period was not considered a limiting factor because, during that time, most agricultural fields are bare and many are flooded or wet, providing ample foraging habitat. However, the southward shorebird migration occurs from late July through September, when most of the field are in crops and flood water is rare. We used estimates of invertebrate density, the caloric value of food in the mud fiats, and the energy needs of shorebirds to calculate the amount of habitat needed. We included the requirement for shorebirds to be able to gain weight so that they can replenish muscle and fat lost during migration to the Mississippi Alluvial Valley and have enough energy to continue their journey south. We estimate that 2,000 hectares (5,000 acres) of mudflat habitat will be required. This requirement is distributed among various State and Federal management areas, and at this time it appears that the entire goal can be met on public lands. However, we recognize that substantial shorebird habitat exists on private lands, especially at aquaculture facilities (catfish, crawfish, and bait fish farms are common and widespread in the Mississippi Alluvial Valley). Enhancement of these habitats will be encouraged wherever possible.
To arrive at these goals and recommendations, we made several critical assumptions that should be tested. As habitat development proceeds in response to this plan, research and monitoring will measure the adequacy of these habitat recommendations in meeting the population goals. As we identify shortcomings, management recommendations will be adjusted to incorporate new information.
This planning process has developed a site-specific, coordinated plan that should meet the habitat needs of three groups of migratory birds. To achieve a more complete "ecosystem plan," we will add the habitat needs of other species as their needs are defined. Two important efforts promise to add information in the near future. The Lower Mississippi River Conservation Committee is preparing an Aquatic Management Plan for the lower Mississippi River and the Black Bear Conservation Committee is defining the site-specific needs of the threatened Louisiana black bear (Ursus americanus luteolus). Recognizing that the primeval forest cannot be reestablished, we hope to restore the essence of Faulkner's Woods by providing the habitat requirements for as many species as possible.
Allan J. Mueller is the Field Supervisor for the FWS Vicksburg, Mississippi, Field Office.
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|Title Annotation:||William Faulkner|
|Author:||Mueller, Allan J.|
|Publication:||Endangered Species Bulletin|
|Date:||Jul 1, 1998|
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