Molluscan community recovery in a New England back-barrier salt marsh lagoon 10 years after partial restoration

  • Published source details Thiet R.K., Kidd E., Wennemer J.M. & Smith S.M. (2014) Molluscan community recovery in a New England back-barrier salt marsh lagoon 10 years after partial restoration. Restoration Ecology, 22, 447-455.


This study is summarised as evidence for the following.

Action Category

Restore coastal lagoons

Action Link
Subtidal Benthic Invertebrate Conservation
  1. Restore coastal lagoons

    A study in 2005–2011 in a lagoon connected to Cape Cod Bay, Massachusetts, USA (Thiet et al. 2014 – same experimental set-up as Thelen & Thiet 2009) found that, between three and nine years after restoring its connection to the sea, species richness and abundances of molluscs that had recolonised the lagoon following reconnection were decreasing over time, but effects varied geographically within the lagoon. Species richness decreased from 16 in 2005 to eight in 2011 across the lagoon, due to significant decreases in Moon Pond (from 14 to 5). Abundance of mollusc species also declined over time (total values not provided, see paper for details on each species abundance). Abundance of the softshell clam Mya arenaria (the dominant species in the lagoon and only one present in all areas each year), declined between 2005 and 2011, from 3,200/m2 to 8/m2 in Moon Pond and from 2,900/m2 to 7/m2 in the central lagoon, and remained low in northwest cove (0.2/m2 in 2005, 1/m2 in 2011). In 2002, tidal flow was partially restored to East Harbor lagoon (dominated by freshwater) by opening a culvert connecting to Cape Cod. Previously, no molluscan species were reported. In summer 2007, 2008 and 2011, locations within three areas of the lagoon were surveyed (Moon Pond: 20 locations; central lagoon: 24–30 locations; northwest cove: 4–15 locations) using cores (0.79 m2). Molluscs (>1 mm) were identified and counted. Data were compared to 2005 data from a previous study by Thelen & Thiel (2009) summarised above.

    (Summarised by: Anaëlle Lemasson)

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