Search results for " Arbacia"

Functional traits of two co-occurring sea urchins across a barren/forest patch system

2013

Abstract Temperate rocky reefs may occur in two alternative states (coralline barrens and erect algal forests), whose formation and maintenance are often determined by sea urchin grazing. The two sea urchin species Paracentrotus lividus and Arbacia lixula are considered to play a similar ecological role despite their differing morphological traits and diets. The patchy mosaic areas of Ustica Island, Italy, offer an ideal environment in which to study differences in the performance of P. lividus and A. lixula in barren versus forest states. Results show that the two sea urchin species differ in diet, trophic position, grazing adaptation, movement ability and fitness in both barren and forest…

Sea temperature and echinoid Arbacia lixula (L.) population fluctuations on Ustica Island MPA

2009

Il Plemmirio e le altre AMP Mediterranee

2011

Role of two co-occurring Mediterranean sea urchins in the formation of barren from Cystoseira canopy

2015

Abstract In the Mediterranean Sea the co-occurring sea urchins Paracentrotus lividus and Arbacia lixula are usually considered to share the same ecological role in the formation of barren from Cystoseira canopy. However, their foraging ability may vary due to feeding behavior and species-specific morphological traits. The relative effects of P. lividus and A. lixula on Cystoseira canopy was tested experimentally both in the laboratory, at a density of about 20 ind./m 2 , and in the field by gut content analysis. Field and laboratory results show that A. lixula is unable to affect Cystoseira spp. Furthermore, these results confirmed the great ability of P. lividus to consume Cystoseira canop…

Effetto del substrato sulla tenacità di attacco e sulla predazione dei ricci Paracentrotus lividus (Lmk) nell’AMP Isola di Ustica.

2008

Population structure of the sea urchins Paracentrotus lividus and Arbacia lixula across a depth gradient

2006

Sea urchins are considered to have a paramount role in structuring rocky shallow communities. Under certain conditions, grazing by sea-urchins has been reported to produce a shift from macroalgae-dominated communities to barren habitat dominated by encrusting algae. However, this process is not recorded at all depths. The effect of depth on the structure of the sea-urchin populations may be thus a key feature to understand the origin and maintenance of the barren habitat within certain depths. In the present study, the structure of Paracentrotus lividus (Lam.) and Arbacia lixula (L.) populations are analyzed across a depth gradient in the Ustica Island MPA (NW Mediterranean), where the barr…

Ciclo riproduttivo di Arbacia lixula (Linneo, 1758) (Echinodermata: echinoidea) nella AMP “Isola di Ustica”

2009

Biologia ed ecologia riproduttiva di Arbacia lixula (Linneo, 1758)

2012

The effects of recreational Paracentrotus lividus fishing on distribution patterns of sea urchins at Ustica Island MPA (Western Mediterranean, Italy)

2006

This study evaluated the effects of recreational Paracentrotus lividus fishing on average density and size of this edible sea urchin, and its indirect effects on Arbacia lixula on barren substrates of Ustica Island MPA (SW Italy, Mediterranean Sea). Size, single and pooled species densities, density of large individuals (>40 mm long) and small individuals (<20 mm long) of the two species were estimated by scuba diving in autumn 2003, spring and summer 2004 at two sites impacted by P. lividus fishing (Punta Cavazzi and Pagliaro, take zone C) and one control (Cala Sidoti, no take zone). Two samplings were performed in each season. We found that reduced densities of P. lividus and A. lixula oc…