Distribution pattern of zoanthids (Cnidaria: Zoantharia) on a tropical reef

Abstract

Coastal reef environments support a great diversity of benthic species, which are physically arrayed according to their adaptations to biotic factors such as competition and to abiotic factors such as salinity and desiccation. Few studies have described adaptive strategies on rocky shores in tropical regions. This contribution deals with the spatial distribution of three species of zoanthids (Palythoa caribaeorum, Protopalythoa variabilis and Zoanthus sociatus) on flat sandstone reefs in northeastern Brazil. Zoanthid distribution and abundances were determined as the percentage of cover along six transects, where 50 × 50 cm quadrats were sampled. Biotic data (influence of macroalgal cover) and abiotic data (relief, substrate type, temperature and salinity) were also taken along the transects to attempt to explain the zoanthid distribution. These species tended to colonize the middle and low intertidal zones, which are least exposed to air. Zoanthus sociatus apparently resists desiccation better than P. caribaeorum. Protopalythoa variabilis showed the highest abundance and frequency, occurring in the entire middle intertidal zone and colonized areas with high proportions of unconsolidated sediment. Desiccation was the main factor limiting the spatial distributions of the three species, although substrate composition and probably interspecific competition with macroalgae were also important. The results suggest that the zoanthids use a variety of these adaptive strategies, which account for their success on consolidated substrates. Continuous monitoring of changes in distribution patterns can be useful for indicating human impacts on marine biodiversity, providing insights for monitoring and conservation programmes.

DISTRIBUIÇÃO ESPACIAL DE MACROALGAS E DO ZOANTÍDEO Palythoa caribaeorum (DUCHASSAING e MICHELOTTI, 1860) NO NORDESTE DO BRASIL

“…A distribuição dos zoantídeos é afetada por diversos fatores físicos e biológicos, entre eles, a exposição à dessecação, o tipo de substrato e a competição com macroalgas possuem efeitos mensuráveis (RABELO et al, 2015). Mudanças no padrão de distribuição de zoantídeos ao longo do tempo podem ser utilizados como indicadores de impacto antrópico, incentivando a implementação de programas de conservação de ambientes recifais (RABELO et al, 2015).…”

Checklist of polychaetes (Annelida: Polychaeta) from a sandstone reef of Southeastern Brazil

“…These formations consist of rectilinear rock structures, which are parallel to the coastline and can be uncovered at low tides (Correia and Sovierzoski, 2009). Differ from a typical rocky shore and coral reefs mainly because of their gentle slope and sedimentary composition (Rabelo et al, 2015). These consolidated substrates are formed by the sedimentation of ancient Quaternary sandbanks through chemical reactions with calcium carbonate and are usually arranged along parallel lines to the coast and near the mouths of rivers and estuaries (Correia and Sovierzoski, 2009;Correia, 2010;Padula et al, 2012).…”

Photobiology of the zoanthid Zoanthus sociatus in intertidal and subtidal habitats

“…However, research on zoantharian ecology has been scarce as compared with other cnidarian groups (Hill 2013). The prevalence of zoantharian species hosting photosynthetic symbionts in reef flats and in wide range of tidal heights (Sebens 1982;Rabelo et al 2015) suggests the presence of photobiological processes well prepared to deal with environmental variability associated with tidal cycles. However, photobiological adaptations of symbiotic zoantharians differently exposed to tides remain poorly explored.…”