Ecological impacts of the spread of non-native oysters and interactions with native oysters

• Main Author: Zwerschke, Nadescha
• Published: Queen's University Belfast 2016
• Subjects: 594
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709886

Non-native species can have negative effects on local ecosystems by interrupting ecosystem functioning and altering biodiversity. Non-native ecosystem engineers, such as oysters, may have substantial impacts on ecosystems, by altering the physical structure of habitats and changing ecological processes within an invaded community. The non-native Pacific oyster, Crassostrea gigas, was introduced to Europe to revive the aquaculture industry, which was weakened following the decline of the native European flat oyster, Ostrea edulis. The introduction of C. gigas and subsequent natural proliferation in many coastal regions of Europe has caused great controversy in the scientific community. Initially, it was argued that C. gigas would have detrimental effects on the recovery of 0. edulis beds and alter the functioning of invaded coastal ecosystems. It has also been argued, however, that the spread of C. gigas often increased local biodiversity and reduced the impacts of coastal erosion. To assess the impact of C. gigas explicitly based on robust empirical evidence, an extensive survey and three field-based experiments were carried out. The aims were to: (i) identify and describe the current distribution of G. gigas populations in Ireland; (ii) test for direct effects of C. gigas on native 0. edulis beds; and (iii) characterise the functional ecology of C. gigas and compare it with the morphologically similar native species, 0. edulis.