Spatial variability, structure and composition of crustose algal communities in Diadema africanum barrens

Abstract

Crustose algal communities were studied in Diadema africanum urchin barrens around Tenerife (Canary Islands, NE Atlantic). A hierarchical nested sampling design was used to study patterns of community variability at different spatial scales (sectors, three sides of the island; sites within each sector, 5-10 km apart; stations within each site, 50-100 m apart). Although noncrustose species contributed the most to community richness, cover was dominated by crustose forms, like the coralline algae Hydrolithon farinosum, H. samoënse, H. onkodes, Neogoniolithon orotavicum and N. hirtum, and the phaeophycean Pseudolithoderma adriaticum. The structure of these communities showed high spatial variability, and we found differences in the structure of urchin barrens when compared across different spatial scales. Multivariate analysis showed that variability in community structure was related to the five environmental variables studied (wave exposure, urchin density, substrate roughness, productivity and depth). Wave exposure was the variable that contributed most to community variability, followed by urchin density and substrate roughness. Productivity and depth had limited influence. The effects of these variables differed depending on the spatial scale; wave exposure and productivity were the main variables influencing community changes at the largest scale (between different sectors of the island), while D. africanum density, roughness and depth were the most influential at medium and small scales.

Trophic ecology of sea urchins in coral-rocky reef systems, Ecuador

“…This has also been observed in other areas of the ETP where D. mexicanum has a relevant role in the recruitment of corals ( Alvarado, Cortés & Reyes-Bonilla, 2012 ). This was also observed in Caribbean reefs with D. antillarum ( Macintyre, Glynn & Hinds, 2005 ; Mumby et al, 2006 ; Idjadi, Haring & Precht, 2010 ; Sandin & McNamara, 2012 ), and in shaping the sublittoral ecosystems of the Canary Islands with D. africanum ( Alves et al, 2003 ; Tuya et al, 2004 ; Hernández et al, 2005 ; Hernández et al, 2008 ; Sangil et al, 2014 ; Cabanillas-Terán et al, 2015 ).…”

Lobophora (Dictyotales) Species Richness, Ecology and Biogeography Across the North‐Eastern Atlantic Archipelagos and Description of Two New Species1

“…This species and other crustose Lobophora , such as L. littlerorum and L. delicata , are common in D. africanum barrens (Sangil et al. 2014b). In addition, L. canariensis was observed being cultivated by the Canary damsel, Similiparma lurida , within L. schneideri dominated assemblages in the Canary Islands (C. Vieira, pers.…”

Shallow subtidal macroalgae in the North-eastern Atlantic archipelagos (Macaronesian region): a spatial approach to community structure

“…Crustose coralline algae were grouped together owing to difficult in situ identification, but differentiating them to species level would probably have contributed to a more comprehensive biogeographic differentiation among archipelagos, since it is an especially diverse and variable group of species (Sangil et al, 2014b). Apart from crustose corallines, Dictyotales were the most abundant group and best reflected the variation among Macaronesian archipelagos.…”