Vertical zonation of the hydroid Dynamena crisioides (Hydrozoa, Sertulariidae) in a mangrove ecosystem at Twin Cays, Belize

Calder, Dale R. (1991) Vertical zonation of the hydroid Dynamena crisioides (Hydrozoa, Sertulariidae) in a mangrove ecosystem at Twin Cays, Belize. Canadian Journal of Zoology (CJZ), 69. pp. 2993-2999. ISSN 1480-3283

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    Abstract

    Dynamena crisioides is generally restricted to lower intertidal and shallow subtidal habitats along tropical and subtropical coasts. The hydroid was abundant during this study on prop roots of red mangroves (Rhizophora mangle) at Twin Cays, Belize, where it ranged vertically from 1.1 m below mean tide level (MTL) to 2-3 cm above MTL. The estimated percentage cover of the hydroid was maximal in the lower half of the intertidal zone (MTL and 0.1 m below MTL) and declined rapidly above and below that level. Colony height and number of branches per colony were also consistently highest in hydroids from the lower half of the intertidal zone. The percentage ofcolonies with gonophores was lowest at the lower and upper vertical limits of the species. Field observations and transplantation experiments suggest that the lower limits of D. crisioides are established by competition for space (with algae, sponges, and ascidians), smothering (by algae, sponges, ascidians, and other hydroids), and predation (by fishes). Desiccation was considered the prime factor determining the upper limits of the hydroid. Colonies transplanted to the supratidal zone were in good condition after 24 h, alive but in poor condition after 48 h, and dead after 72 and 96 h of exposure.

    Item Type: Peer-reviewed Journal Article
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      Publisher: National Research Council Canada
      Keywords: zonation, hydroid, mangrove ecosystem,
      Subjects: (A) Biodiversity > (AF) Invertebrates > (AFB) Marine
      (C) Ecosystems > (CB) Marine > (CBE) Mangroves
      Publication Sources: (3) Other Source > (3D) Other or Unspecified
      Date Deposited: 31 Jan 2011 14:06
      Last Modified: 31 Jan 2011 14:06
      URI: http://eprints.uberibz.org/id/eprint/1253

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