Biological introductions, that is the human-mediated transport and establishment of species in new regions, is now widely recognised as a phenomenon of global import. No region of the world remains untouched, making biological introductions one of the most persistent threats to environmental, economic and social issues across terrestrial, freshwater and marine environments. These impacts are well acknowledged in terrestrial and freshwater contexts, however the awareness and study of marine introductions remains a relatively young field of research. As a consequence, our understandings of drivers, impacts and ultimately risks remain fraught with uncertainty.
Marine biosecurity, that is the management of human mediated marine introductions through prevention, transport controls and post-establishment response, is now recognised as a focus of marine and coastal management. Due to limited knowledge and significant uncertainty across multiple domains, risk assessment has increasingly become the tool of choice for marine biosecurity, comprising both the likelihood and consequences of events such as the invasion of a species. Our ability to undertake appropriate biosecurity protection requires a foundation of knowledge across a wide range of disciplines to determine what we are protecting and what interventions are acceptable.
In this talk, Hewitt will provide a high-level background of our current knowledge of marine biological introductions, specifically focusing on the progress we are making in understanding patterns of global invasions, the relative contributions of transport mechanisms and how these inform predictive abilities and the estimation of risk. The discussion will provide an exploration of how we measure impacts that inform the underlying requirements for justifying action and the mechanisms of intervention to manage and control marine introductions.
Marine biological introductions provide salient examples of human mediated global change, and development of marine biosecurity policy and operational responses is thusly justified to protect coastal values and ecosystem attributes. Future (immediate and long-term) concerns however also indicate that lessons from biological invasions (in general) and human-mediated introductions (in particular) may provide insights for conservation and resource managers as communities begin to disassemble in the face of increasing urbanisation (and associated pressures) and climate change. For example, biological introductions provide a window into the assembly of novel species combinations analogous to interactions occurring at expanding range edges. Similarly, many biological introductions demonstrate release from enemies (predators, parasites and competitors) resulting in high population variability and rapid adaptation in ecological timeframes. These insights aid our understanding of conservation risk for native species and communities and help inform decision making for intervention into the future.
Chad Hewitt, University of Waikato, New Zealand