Succession of benthic hard bottom communities in the Chilean Comau fjord revisited


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Juergen.Laudien [ at ] awi.de

Abstract

Both natural and anthropogenic impacts can lead to major disturbances of marine benthic ecosystems. Such disturbances can cause the formation of newly freed habitat, which have to be recolonized. While there are a large number of studies on succession only few have been conducted for benthic cold water hard bottom communities. This thesis reassesses the conclusions of Reichel (2012) on the succession at two study sites in the fjord Comau, Chile, in 2012. Nine plates have been installed at each study site and have been documented by photography from 2010 until this year. In addition the surrounding environment has also been photographed. The pictures taken were analyzed for species abundance and coverage. Statistical community analysis was applied to the resulting data. At both sites over 50 different species were detected. While abundance decreased after 2012, the percentage cover increased continuously from 2010 until 2018. Especially sponges, octocorals and brachiopods increased in abundance and coverage, while the coverage through bryozoans was reduced. Biodiversity indices increased and stabilized at levels similar of the natural community. Multivariate analysis revealed a development of the recruitment plates towards the natural community; still they did not reach the same structure as the natural environment. The data supports the previous assessment that succession of the hard bottom community in Comau fjord follows the TOLERANCE MODEL (Connell & Slayter, 1977). However abiotic factors have shown to strongly influence the development of the community. This shows that the succession is not CANALIZED but EXTERNALLY DRIVEN (Berlow, 1997). All together the community showed high resilience and stability. Nevertheless the slow growth rates of cold-water communities, especially the dominant stony coral Desmophyllum dianthus, cause the system to have long recovery times. Therefore the communities on the recruitment plates have still not reached maturity.



Item Type
Thesis (Master)
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Primary Division
Programs
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Peer revision
Not peer-reviewed
Publication Status
Published
Eprint ID
52288
Cite as
Hutzschenreuter, T. (2018): Succession of benthic hard bottom communities in the Chilean Comau fjord revisited , Master thesis, Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung and Universität Rostock.


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