Biodiversity & Conservation

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.

• Potamogeton pectinatus
• Cladophora flexuosa
• Cladophora liniformis
• Potamopyrgus jenkinsi
• Gasterosteus aculeatus
• Lamprothamnium papulosum

• Lamprothamnium papulosum

Potamogeton pectinatus provides primary productivity, cover and substratum, and is the defining characteristic species within this biotope (Connor et al. 1997a; Rodwell, 1995). Potamogeton pectinatus is therefore considered to be key structural species. Grazers are probably important species in the food chain converting Potamogeton pectinatus 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 macrophytes. Hydrobia ulvae is included to represent gastropod grazers, while reference was made to Gammarus salinus and Gammarus insensibilis (the lagoon sand shrimp) to represent gammarid amphipod grazers. The hydroid Cordylophora caspia and bryozoan Conopeum reticulum have been used to represent brackish water epifauna. The mysid Neomysis integer has been used to represent the sensitivity of mysid species. Similarly, Pomatoschistus minutus has been used to represent the sensitivities gobies and other small fish.

A large number of species have been identified within Potamogeton pectinatus dominated communities. The Potamogeton pectinatus community NVC A12 included 14 other species of macrophyte (Rodwell, 1995). Verhoeven & van Vierssen (1978) reported 23 invertebrate species within mixed Potamogeton pectinatus and Ruppia spp. communities, while van Vierssen & Verhoeven (1983) reported 24 species of Coleoptera, and 12 species of Heteroptera in Potamogeton pectinatus dominated communities in the Netherlands. In addition, Cunha & Moreira (1995) identified 76 taxa in the Potamogeton and Myriophyllum beds in Canal de Mira, Portugal.