Ecosystem Engineering Effects of Aster tripolium and Salicornia procumbens Salt Marsh on Macrofaunal Community Structure

Abstract

This paper examines how perennial Aster tripolium and annual Salicornia procumbens salt marshes alter the biomass, density, taxon diversity, and community structure of benthic macrofauna, and also examines the role of elevation, sediment grain size, plant cover, and marsh age. Core samples were collected on a fixed grid on an intertidal flat in the Westerschelde estuary (51.4°N, 4.1°E) over 5 years (2004)(2005)(2006)(2007)(2008) of salt marsh development. In unvegetated areas, macrobenthic biomass, density, and taxon diversity were highest when elevation was highest, benthic diatoms were most abundant, and sediment median grain size was smallest. In contrast, in salt marsh areas, macrobenthic biomass and taxon diversity increased with median grain size, while the effects of elevation and diatom abundance on macrobenthic biomass, density, and diversity were not significant. In fine sediments, macrofaunal community structure in the salt marsh was particularly affected; common polychaetes such as Nereis diversicolor, Heteromastus filiformis, and Pygospio elegans had low abundance and oligochaetes had high abundance. Marsh age had a negative influence on the density of macrofauna, and A. tripolium stands had lower macrofaunal densities than the younger S. procumbens stands. There were no significant effects of marsh age, plant cover, and vegetation type on macrobenthic biomass, taxon diversity, and community structure. The results highlight that ecosystem engineering effects of salt marsh plants on macrofauna are conditional. Organic enrichment of the sediment and mechanical hindering of macrofaunal activity by plant roots are proposed as plausible mechanisms for the influence of the salt marsh plants on macrofauna.

Salt Marsh Establishment and Eco‐Engineering Effects in Dynamic Estuaries Determined by Species Growth and Mortality

“…The investigated intertidal flat is a 4 km long bar located in the 160 km long Western Scheldt estuary, the Netherlands (Figure ). The dynamic tidal bar of Walsoorden experienced recent salt marsh establishment starting from the 1990s and has been intensively studied for understanding its bed form patterns, morphological, habitat and salt marsh development, and macrobenthic dynamics (Cleveringa, ; De Vet et al, ; Plancke et al, ; Van der Wal et al, , ; Van der Wal & Herman, ).…”

What Came First, Mud or Biostabilizers? Elucidating Interacting Effects in a Coupled Model of Mud, Saltmarsh, Microphytobenthos, and Estuarine Morphology

“…During the last decades, heavy dredging and dumping activities have been carried out to provide sufficiently deep channels to access the port of Antwerp (Leys et al., 2006; Plancke et al., 2017). To understand ecological functioning, many studies investigated human‐induced effects on biodiversity and development of tidal shoals (e.g., Ides et al., 2007; Van der Wal & Herman, 2012; Van der Wal et al., 2008, 2011). The entire Western Scheldt was mapped for specific years as ecotope maps by the Dutch Water Authorities (RWS) that give information on the vegetation cover, different morphological classes, and sediment types in a 3‐ to 4‐year interval (available on the website of RWS).…”

Multiple Environmental Variables Affect Germination and Mortality of an Annual Salt Marsh Pioneer: Salicornia procumbens

“…The shaded grey areas correspond to the 95% confidence interval for the predictions rates may occur, for example between higher temperature and lower salinity (Huiskes et al 1985;Ungar 1967). When temperatures increase early in the season, the growing season can be prolonged and early cohorts have advantage over later cohorts (Ungar 1987). The length of the growing season will affect the size of S. procumbens individuals and its reproductive success (Davy et al 2001).…”