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Silvia Saloni School of Biology & Environmental Science |
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Biodiversity - ecosystem functioning relationships in a changing environment: impacts of changes in density, population structure and evenness
In the last century, increasing human impacts on natural ecosystems have caused a great loss of biodiversity and associated alterations to community structure. Particularly pertinent in this context are rocky shores, as they are among the marine systems most threatened by man’s activities and are therefore quite likely to suffer increased rates of local extinction in the coming years. It is therefore important to understand what the community and ecosystem level consequence of biodiversity loss will be.
As Worm and Duffy (2003) concluded, changes in biodiversity can be both a cause and a consequence of changes in productivity and stability and this bi-directionality creates feedback loops, as well as indirect effects, that influence the complex responses of communities to biodiversity losses. Important, but often neglected, mediators of this complexity are trophic interactions. Recent work shows that consumers can modify, dampen or even reverse the directionality of biodiversity-productivity stability linkages inferred from the producer level alone in many ecosystems. In this context, my PhD project will use intertidal rock pools as a model system to test the following hypotheses:
1) population structure of key species will influence ecosystem functioning;
2) evenness of species will influence ecosystem functioning;
3) overall density will modify effects of population structure and evenness;
4) consumers influence the structure and functioning of ecosystems;
5) impacts of changes of density, population structure and evenness will vary depending on environmental conditions.
To test these hypotheses, a series of field and laboratory experiments will be done. The laboratory experiments will be run in the new MARBEE aquarium facility, while the field experiments will be run in a new set of natural rockpool, County Galway.
This work is supervised by Dr Tasman Crowe and supported by the IRCSET Postgraduate Research Scholarship Scheme 2009.