|In vitro experimental assessment of the grazing pressure of two gastropods on Zostera marina L. ephiphytic algae|Hily, C.; Connan, S.; Raffin, C.; Wyllie-Echeverria, S. (2004). In vitro experimental assessment of the grazing pressure of two gastropods on Zostera marina L. ephiphytic algae. Aquat. Bot. 78(2): 183-195. dx.doi.org/10.1016/j.aquabot.2003.10.001
In: Aquatic Botany. Elsevier Science: Tokyo; Oxford; New York; London; Amsterdam. ISSN 0304-3770, more
Epiphytes; Experimental research; Grazing; Herbivores; Sea grass; Seasonality; Gibbula umbilicalis (da Costa, 1778) [WoRMS]; Jujubinus striatus (Linnaeus, 1758) [WoRMS]; Zostera (Zostera) marina Linnaeus, 1753 [WoRMS]; ANE, France, Brittany, Brest Bay [Marine Regions]; Marine
|Authors|| || Top |
- Hily, C.
- Connan, S.
- Raffin, C.
- Wyllie-Echeverria, S.
This study experimentally assessed the impact of gastropod grazing on epiphyton biomass and taxonomic composition on leaves of the seagrass Zostera marina L. along the coasts of Brittany, France. Image analysis was used to measure the same section of a leaf before and after grazing and assess grazing pressure. It was found that: (1) both grazers, Gibbula umbilicalis and Jujubinus striatus, were highly efficient in reducing epiphytic cover; (2) J. striatus showed a higher specific grazing rate than G. umbilicalis at an equivalent animal biomass; (3) J. striatus increased its activity when epiphytic biomass increased. Analysis of the variability of epiphytic cover along the leaves showed considerable heterogeneity from the basal part of the external leaves of a shoot to the apex. The development of long filamentous algae (mainly ectocarpales) in spring and summer and their concentration at the apex intensified shading impact on the seagrass bed. The grazing of both gastropod species was also concentrated at the apex, thereby enhancing their role in moderating the shading effect.