Factors Determining the Stability of Marine Fouling Communities in Tokyo Bay, Japan.

Link, Heike H. D. (2007) Factors Determining the Stability of Marine Fouling Communities in Tokyo Bay, Japan. (Diploma thesis), Ruprecht-Karls-Universität, Heidelberg, Germany, 81 pp.

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Abstract

During the last decades, marine ecosystems have experienced an increasing amount of bioinvasions mediated by human activities, which have often caused irreversible changes in
the affected environment. Recent studies have revealed ship traffic as a major anthropogenic pathway and source for introductions. However, the role of sessile epibenthic communities attached to ship hulls, i.e. fouling communities, as a source of species’ invasion after transport to a new environment has hardly been investigated. The first obstacle for a transported species
to become invasive is its survival in the new habitat. For a transported organism, the probability to establish successfully should increase with the stability of the community it is part of. Controversially discussed concepts predict the ability of a transported community to
resist against environmental changes and recruitment by the local, non-indigenous species based on its diversity.
The present study aims to investigate the mechanisms that determine the stability of marine fouling communities after transport into a new environment. Assemblages of two
different successional stages (2-months and 4-months old) were transplanted from a port site to a lagoon site, and vice versa, in the inner Tokyo Bay, Japan. Their stability was measured as the rate at which they converged to local communities of the same successional stage in terms of community composition. In all cases, older transplanted fouling communities converged slower towards their native counterparts than younger ones. Subsequent analyses
on community diversity and available settlement substratum – the most important resource in hardbottom communities – and the convergence rate did not detect any significant
relationship between them. Instead, the identity and life strategy of species present in the transplanted communities as well as the species present in the environment were the most important factors determining the persistence of the introduced communities. More precisely, bivalves and a serpulid worm strongly enhanced the stability of fouling communities in the new environment, while Molgula manhattensis and Polydora cornuta accelerated the
convergence process by rapid recruitment from the local environment into the introduced communities and as well by mortality after transport of the second species. The importance of key species and their life strategies does not support the diversity-stability hypothesis and should lead to a concept that predicts community stability from the life strategy of component species. Moreover, as a practical implication of this study, the establishment of fouling communities on mobile substrata should be controlled in order to reduce the risk of marine bioinvasions caused by matured fouling communities

Document Type: Thesis (Diploma thesis)
Thesis Advisors: UNSPECIFIED
Additional Information: Referent: Prof. Dr. Dr. h.c. Volker Storch, Korreferent: Prof. Dr. Martin Wahl
Keywords: Benthic Ecology; GAME; bioinvasion; marine fouling communities; Tokyo Bay, Japan
Research affiliation: OceanRep > GEOMAR > FB3 Marine Ecology > FB3-EOE-B Experimental Ecology - Benthic Ecology
Refereed: No
Projects: GAME
Date Deposited: 08 Sep 2011 11:36
Last Modified: 06 Jul 2012 15:11
URI: http://oceanrep.geomar.de/id/eprint/12106

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