Biodiversity & Conservation

Ruppia maritima in reduced salinity infralittoral muddy sand

SS.IMS.Sgr.Rup


IMS.Rup

Image Anon. - Ruppia maritima in reduced salinity infralittoral muddy sand. Image width ca 40 cm.
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Distribution map

SS.IMS.Sgr.Rup recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)


  • EC_Habitats

Species indicative of sensitivity

To assess the sensitivity of the biotope, the sensitivity of component species is reviewed. Those species that are considered to be particularly indicative of the sensitivity of the biotope, and for which research has been undertaken in detail are shown below (see selection criteria). The biology of other component species of the biotope is also taken into account wherever information is known to the researcher.

Species found especially in this biotope

  • Ruppia cirrhosa
  • Ruppia maritima
  • Gasterosteus aculeatus
  • Spinachia spinachia
  • Lamprothamnium papulosum
  • Chara aspera

Rare of scarce species associated with this biotope

Community Importance Species name Common Name
Key structural Ruppia maritima Beaked tasselweed
Key structural Ruppia cirrhosa Spiral tasselweed
Important functional Hydrobia ulvae Laver spire shell
Important functional Gammarus spp. A gammarid shrimp
Important other Cerastoderma glaucum Lagoon cockle
Important other Arenicola marina Blow lug
Important other Pomatoschistus minutus Sand goby

Explanation

Ruppia maritima and Ruppia cirrhosa provide primary productivity, cover and substratum, and are the defining characteristic species within this biotope. Ruppia spp. are, therefore considered to be key structural species. Grazers are probably important species in the food chain converting Ruppia spp. and algal primary production to secondary production, directly available to their predators and to the wider community via the detrital food chain. In addition, their grazing activities probably control the growth of epiphytes that would otherwise shade or compete with the Ruppia spp. Hydrobia ulvae is included to represent gastropod grazers, while reference was made to Gammarus insensibilis (the lagoon sand shrimp) to represent gammarid amphipod grazers. Cerastoderma glaucum was recorded within western European and UK Ruppia dominated communities and is used to represent bivalve suspension feeders within the biotope. While other bivalve species occur in the biotope, the lagoon cockle better represents a species characteristic of brackish, lagoonal, habitats. Arenicola marina is a characterizing species within this biotope and is used to represent the sensitivity of other polychaete species. Similarly, Pomatoschistus minutus has been used to represent the sensitivities of other small fish and goby species.

Additional information

A large number of species have been identified within Ruppia dominated communities. For example, the MNCR recorded 207 species within recorded of the IMS.Rup biotope (JNCC, 1999), however, this number was summed over all records of the biotope. Verhoeven (1980a) recorded between 5-36 species within Ruppia communities, which was low when compared to freshwater aquatic plant or marine seagrass communities (Verhoeven, 1980a, Table X). Verhoeven (1980a) concluded that the relative low species richness of Ruppia dominated communities was due to the physiological stress of brackish waters, the simplicity of the community structure and the dynamic, seasonal variation in Ruppia beds. Verhoeven (1980a) also noted that most species recorded within the community are not closely associated with Ruppia itself, but are generalist euryhaline species capable of utilizing other substrata, e.g. he noted that only 15 of ca 60 species recorded were directly dependant on the aquatic vegetation in the Ruppia communities studied. However, Verhoeven (1980a) was able to identify 7 Ruppia dominated communities (biocoenoses) within northwest Europe.


This review can be cited as follows:

Tyler-Walters, H. 2001. Ruppia maritima in reduced salinity infralittoral muddy sand. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 16/09/2014]. Available from: <http://www.marlin.ac.uk/habitatreproduction.php?habitatid=266&code=1997>