SALT MARSH: Population/Habitat Objectives

Species that require high-marsh habitats are the most threatened marsh-nesting species within the planning unit. These species appear to occur in relatively few sites and in low numbers. Their habitats also appear to be at the most risk within the region. Without deliberate action populations may continue to decline due to habitat degradation. By comparison, there is currently relatively little concern for species associated with low-marsh habitats. Objectives should focus on identifying and protecting remaining large blocks of high marsh habitat.

Most of the species that depend on high marsh habitats are poorly represented on BBS surveys (species detected in <20% of routes). Consequently, basic distribution and population information is lacking. Targeted surveys are needed to better refine habitat requirements and breeding densities so that adequate population estimates may be generated.

Objective 1) To maintain enough high-marsh habitat to support 200 pairs of Henslow's Sparrows (goal of 400 shared with grassland habitats).

Justification: The Henslow's Sparrow is in danger of extinction within the planning unit. No systematic work has been conducted to determine specific resource requirements for this species within the region. Currently, its distribution and status within this habitat type are very poorly known. This species seems to require patches of high marsh that are 50-100 ha in area and that have a relatively undisturbed marsh-upland ecotone (it may also have been a component of the associated maritime pine savannah). It is unlikely that such sites were ever common within the physiographic region. However, remaining sites are threatened. Where they currently exist, patches need to be identified and protected from further degradation.

Assumptions: Maintaining high marsh habitat to support Henslow's Sparrows will provide adequate habitat to support populations of the Black Rail, Salt Marsh Sharp-tailed Sparrow, and Sedge Wren. Although each of these species require somewhat different components of the high marsh, all appear to be very area-sensitive. Extensive patches of high marsh are believed to provide requirements for the entire species suite.

Objective 2) Maintain enough salt marsh habitat to support 50,000 pairs of Seaside Sparrows with their current distribution.

Justification: All of the species most associated with low-marsh habitats are widespread and common to abundant within appropriate habitat. None of these species are threatened within the planning unit. However, anticipated losses of marsh habitat due to sea-level rise may result in population declines and contractions in distribution. Degradation of marshes around population centers may also lead to localized declines.

Assumptions: Maintaining adequate low-marsh habitat to support the Seaside Sparrow will also provide adequate habitat for the Clapper Rail and other associated species.