0000000000458073
AUTHOR
C. Bonaviri
Feeding preferences of Paracentrotus lividus exposed to native and non-native macroalgae
The effects of alien macroalgal invasions on ecosystem functioning may depend on the feeding choice of native herbivores between native and non-native algae. The co-occurrence of two invasive Caulerpa species, C. taxifolia var. distichophylla and C. cylindracea in Southern Sicily, offered the possibility to investigate the feeding preferences of a generalist native grazer, the sea urchin Paracentrotus lividus, for native vs non-native food. A multiple choice feeding experiment was set to assess whether and to which extent P. lividus consumes the exotic macroalgae while in presence of the preferred native ones. Multiple choice feeding assays were run with the following food sources simultane…
Habitat effect on distribution and feeding of Ophidiaster ophidianus (Lmk.) (Asteroidea)
The purple starfish Ophidiaster ophidianus is an Atlanto-Mediterranean starfish protected under the EU’s Habitats Directive. Despite the wide distribution and the current range expansion of this warm affinity species in the northern Mediterranean areas, nothing is known about its diet. Using field observations and carbon (δ13C) and nitrogen (δ15N) stable isotopes, we explored possible changes in density and diet of O. ophidianus in relation to two different Mediterranean habitats: the coralline barren and the macro algae forest. Data were collected at the Marine Protected Area of Ustica Island (Southern Tyrrhenian Sea) from June to September 2009. Starfish density was not affected by the ha…
Macroalgal forest vs sea urchin barren: Patterns of macro-zoobenthic diversity in a large-scale Mediterranean study: Macro-zoobenthos of barren and macroalgal forests
The study aimed at contributing to the knowledge of alternative stable states by evaluating the differences of mobile and sessile macro-zoobenthic assemblages between sea urchin barrens and macroalgal forests in coastal Mediterranean systems considering a large spatial scale. Six sites (100 s km apart) were selected: Croatia, Montenegro, Sicily (Italy), Sardinia (Italy), Tuscany (Italy), and Balearic Islands (Spain). A total of 531 taxa, 404 mobile and 127 sessile macro-invertebrates were recorded. Overall, 496 and 201 taxa were found in macroalgal forests and in barrens, respectively. The results of this large-scale descriptive study have met the expectation of lower macrofauna complexity …
New body metrics to determine asteroid size and weight directly in the field
Asteroids are an important group of predators in many marine ecosystems. The measure of body size is crucial in studying asteroid biology as this variable affects both prey selection and predation impact. Current field techniques for estimating asteroid size (i.e. total length TL, total weight TW) include the measure of correlated variables, such us the central disk (CD) and arm length (AL). However, these variables are often time-consuming and require a direct handling of the organism. We tested the accuracy of new asteroid body metrics, the arm height (AH) or arm width (AW), to rapidly estimate body size in asteroids. AH and AW were measured in three of the most common Mediterranean aster…