Long-term succession of benthic infauna communities on constructed Spartina alterniflora marshes

Abstract

Benthic infauna communities were characterized along a chronosequence (1 to 28 yr old) of 7 constructed Spartina alterniflora Loisel marshes and 7 natural (reference) marshes to identify patterns of succession following salt marsh creation. Infauna density and species richness (per 7.07 cm 2 core) achieved equivalence to comparable reference marshes within 8 yr following marsh creation. Taxa with dispersing larval stages (e.g. Streblospio benedicti, Capitella sp.) achieved equivalence within 3 yr following marsh creation. Taxa that lack a planktonic dispersal stage, such as tubificid oligochaetes and Manayunkia aesturina, were slower to develop. Densities of Manayunkia did not achieve equivalence to natural marshes until 8 yr after marsh creation. Twenty-five yr elapsed before oligochaete densities of constructed marshes were similar to natural marshes. In constructed marshes, densities of surface-deposit feeders, dominated by Streblospio and Manayunkia, achieved equivalence to natural marshes within 8 yr following marsh creation. Subsurface-deposit feeders, consisting mostly of oligochaetes, did not become equivalent to natural marshes for 25 yr. Predictable trajectories, described by an asymptotic increase over time, existed for total species, species richness, and surface-and subsurface-deposit feeders. Oligochaetes and Manayunkia, which produce nondispersing larvae, exhibited linear trajectories over time. In constructed marshes, total density and density of dominant taxa and trophic groups were strongly correlated with soil characteristics, especially organic C, N, bulk density and macro-organic matter (MOM, the living and dead root and rhizome mat). Non-linear regressions using soil organic C and MOM explained 38 to 40% of the variation in constructed marsh infauna density. The regressions suggest that a threshold of 0.5% soil organic C (500 g m -2 , 0 to 10 cm) and 500 g MOM m -2 (0 to 10 cm) is needed to support infauna densities comparable to densities found in natural marshes. Taxon richness of constructed marshes was more strongly related to vegetation characteristics, especially macro-organic matter quality (e.g. lignin) than soil characteristics. Development of benthic infauna communities following marsh construction requires longer than the 5 yr monitoring period required by many wetland mitigation plans, and as much as 25 yr are needed for some attributes (e.g. oligochaetes) to achieve equivalence.

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

“…The dominance of Oligochaeta in the salt marsh was also found in earlier studies in temperate and arid salt marshes worldwide (Jackson et al 1985;Talley and Levin 1999;Craft and Sacco 2003;Hampel et al 2009;Wang et al 2010). Oligochaeta can reach high abundances in salt marshes, as they can live in the microhabitat created by the root system of the plants and are capable of feeding upon plant detritus ).…”

Long-term response of fishes and other fauna to restoration of former salt hay farms: multiple measures of restoration success

“…Because oligochaetes do not have a larval dispersal stage, they have limited dispersal ability and therefore only slowly invade newly opened habitats (e.g., Levin et al 1996). Typically, the first colonists in newly restored marshes are opportunistic species, such as the spionid polychaete Streblospio benedicti and various species of capitellid polychaetes (Levin et al 1996;Craft and Sacco 2003). Both of these taxa rapidly appeared in the restored marsh and reached abundances comparable to the reference marsh within the first year (Figs.…”

“…In restored or created marshes these factors are usually correlated with the age of the marsh, and typically years to decades pass before these environmental factors become similar to natural marshes (Craft and Sacco 2003). The development of the benthic community will also be affected by the supply of new propagules, which will be dependent on distance from source populations.…”

Local Assessment of Shanghai: Effects of Urbanization on the Diversity of Macrobenthic Invertebrates

“…Many wetland mitigation plans require a 5-year monitoring period of the fl ora and fauna after development projects, but many macrobenthos need longer, even up to 25 years, to recover after changes to their habitats (Craft and Sacco 2003 ). Longterm monitoring studies are thus needed in the future.…”