caa a22 4500 445891351 CHVBK 20180317145617.0 cr unu---uuuuu 170323e20110101xx s 000 0 eng 10.1007/s10750-010-0503-5 doi (NATIONALLICENCE)springer-10.1007/s10750-010-0503-5 Bryozoan assemblages on hard substrata: species abundance distribution and competition for space [Elektronische Daten] [Romina Centurión, Juan López Gappa] Bryozoans are colonial invertebrates that often dominate epibenthic assemblages on the lower surfaces of hard substrata. Competition among neighbouring organisms is usually a critical process regulating biodiversity, and hard substrata have proved to be a suitable model habitat to analyse spatial interactions. We explored the relationships among abundance, species richness, diversity, competitive ability, coverage, available surface, depth and substratum size in an assemblage of bryozoans encrusting pebbles and cobbles in a bank off the eastern mouth of the Strait of Magellan. We also tested whether overgrowth competition can be regarded as hierarchical, and whether the species abundance distribution shows a mode of rare species and a decreasing frequency of increasingly abundant species. Abundance, species richness, diversity and overgrowth competition were highest on the largest substrata. Smaller pebbles tended to be encrusted by the commonest bryozoans, while the rarest species were mainly found on relatively larger clasts. A high proportion of the lower surfaces of most substrata was available for growth. Diversity values of relatively shallow stations were lower than expected under Caswell's neutral model. Interspecific competition was hierarchical, but the abundance of colonies was not related to the competitive ability of each species. The species abundance distribution was bimodal, with a main mode of rare species and a second one partly composed of relatively abundant bryozoans with poor competitive abilities. This study shows that even in an encrusting assemblage where competition is hierarchical, the weakest competitors persist and the dominant species are far from being capable of monopolizing space. Springer Science+Business Media B.V., 2010 Overgrowth competition nationallicence Encrusting bryozoans nationallicence Species abundance distributions nationallicence Commonness and rarity of species nationallicence Hard substrata nationallicence Strait of Magellan nationallicence Centurión Romina Museo Argentino de Ciencias Naturales, Ángel Gallardo 470, C1405DJR, Buenos Aires, Argentina aut López Gappa Juan Museo Argentino de Ciencias Naturales, Ángel Gallardo 470, C1405DJR, Buenos Aires, Argentina aut Hydrobiologia Springer Netherlands 658/1(2011-01-01), 329-341 0018-8158 658:1<329 2011 658 10750 https://doi.org/10.1007/s10750-010-0503-5 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10750-010-0503-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Centurión Romina Museo Argentino de Ciencias Naturales, Ángel Gallardo 470, C1405DJR, Buenos Aires, Argentina aut NATIONALLICENCE 700 1- López Gappa Juan Museo Argentino de Ciencias Naturales, Ángel Gallardo 470, C1405DJR, Buenos Aires, Argentina aut NATIONALLICENCE 773 0- Hydrobiologia Springer Netherlands 658/1(2011-01-01), 329-341 0018-8158 658:1<329 2011 658 10750 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer