Habitat linkages: the effect of intertidal saltmarshes and adjacent subtidal habitats on abundance, movement, and growth of an estuarine fish

Abstract

In this study we used pinfish (Lagodon rhomboides) in field experiments to examine linkages between intertidal saltmarsh and adjacent subtidal habitats. Pinfish are more than twice as abundant in intertidal marshes adjacent to seagrass beds than in those adjacent to the unvegetated subtidal bottom. Movement of pinfish between the marsh edge and the adjacent subtidal habitat was greater for fish captured in areas with both intertidal and subtidal vegetation than in those with intertidal vegetation and adjacent unvegetated mudflats. This movement provides an important link between habitats, allowing transfer of marsh-derived secondary production to subtidal seagrass beds and vice versa. Pinfish held in enclosures with both intertidal and subtidal vegetation were, on average, approximately 90% heavier than fish held in enclosures with intertidal vegetation and unvegetated subtidal bottom. Because saltmarshes and seagrass beds contribute to the production of living marine resources, active measures are being taken to preserve and restore these habitats. The results from this study have direct application to decisions concerning site selection and optimal spatial proximity of saltmarsh and seagrass habitats in the planning of restoration and mitigation projects. To maximize secondary production and utilization of intertidal marshes, managers may opt to restore and/or preserve marshes adjacent to subtidal seagrass beds.

Estimated enhancement of fish production resulting from restoring oyster reef habitat: quantitative valuation

“…The landscape setting in which a reef is placed dictates the ability of many higher-level consumers to utilize it. For example, intertidal oyster reefs placed adjacent to salt marshes or adjacent to subtidal seagrass beds, rather than in isolation from other structured habitats, vary in their functioning by supporting different patterns of fish and crab utilization (Meyer et al 1996, Irlandi & Crawford 1997, Micheli & Peterson 1999, Grabowski 2002. Intertidal and subtidal oyster reefs are likely to differ in value to fish and mobile crustaceans largely because of the need to find alternative submerged refuge at low tide.…”

Movements of Marine Fish and Decapod Crustaceans: Process, Theory and Application

“…This movement pattern would maintain an animal's position in the shallowest water, thereby gaining refuge from aquatic predators and limiting energy expenditure. Regular tidal excursions may benefit growth in some species (Weisberg and Lotrich, 1982;Peterson and Turner, 1994;Irlandi and Crawford, 1997). Studies have shown a tidal periodicity in feeding, as evidenced by fuller guts on ebbing tides than on flooding tides (for fish see Kuipers, 1973;Rountree and Able, 1992; and for crustaceans see Ryer, 1987).…”

“…It is in terrestrial environments, however, that the quantification of landscape pattern and the study of the effect of pattern on ecological processes have made significant advances in understanding animal movement and persistence, the effects of disturbance, the importance of broad-scale environmental change and the design of resource management strategies (Turner, 1989;Saunders et al, 1991;Hobbs, 1994;Forman, 1995;Farina, 1998). Landscape ecology principles and tools are applicable throughout ecology and recent reviews have outlined the usefulness of a landscape ecology approach for the marine environment (Kneib, 1994;Robbins and Bell, 1994;Bell et al, 1997;Irlandi and Crawford, 1997;Eggleston, 1999). These reviews have rekindled interest in spatial pattern in the marine environment, with a number of researchers now applying and further developing concepts and analytical tools that have been used successfully in terrestrial landscape ecology.…”

Effects of habitat modification in mangroves on the structure of mollusc and crab assemblages

“…The proximity to alternative types of habitat has been shown to have important influences on the abundance and diversity of animals in other estuarine systems (e.g. Irlandi and Crawford, 1997).…”