Quantifying the habitat structure and spatial pattern of New Jersey (U.S.A.) salt marshes under different management regimes

• Published in: Wetlands ecology and management 2000-06, Vol.8 (2-3), p.163-172
• Main Authors: Lathrop, R.G, Cole, M.B, Showalter, R.D
• Format: Article
• Language: English
• Subjects: Aquatic insects; Availability; Birds; Brackish; Channels; coasts; control methods; Density; Ecology; ecosystem management; fish; Habitat availability; Habitats; Hydrologic regime; Hydrology; image analysis; littoral zone; Management; Marine; Marshes; mosquito control; Mosquitoes; nekton; ponds; Salt marshes; Tidewater; USA, New Jersey; Wetlands
• ISSN: 0923-4861; 1572-9834
• DOI: 10.1023/a:1008492418788

Mosquito control measures have resulted in major structural alterations of many coastal marshes, with relatively unknown consequences to larger ecosystem functioning. Parallel grid ditching and open marsh water management (OMWM) techniques are purposefully designed to alter the hydrological regime and the relative availability and/or characteristics of standing water on the marsh surface. With the growing recognition of the important influence that habitat structure and the configuration of the marsh-edge boundary has on nekton utilization of salt marsh systems, the impact of mosquito control management techniques on the availability and quality of salt marsh habitat deserves increased scrutiny. Using digital image processing techniques, we completed a detailed mapping effort for a 1800 ha study area in Tuckerton, New Jersey to provide a picture of subtidal and intertidal habitat availability. Spatial analysis techniques were used to quantify the relative amount of habitat types and spatial pattern of the land-water interface under different management regimes: parallel grid-ditched, OMWM and an unaltered reference. The parallel grid-ditched site had a much lower incidence of marsh ponds which serve as important low tide and over-wintering refuge for certain species of fish. In comparison, the OMWM site had a much greater amount of ponded water habitats.The grid-ditched site had a higher density of marsh surface-to-tidal water interface resulting in a lower median distance between the marsh interior and the adjacent tidal channel network. This study serves to benchmark the habitat structure and spatial pattern of a highly functioning natural marsh for use as a reference site in regional wetland creation or restoration efforts.