Dr Asta Audzijonyte1,2, Dr Rick Stuart-Smith1, Dr Gretta Pecl1,2, Dr Julia Blanchard1,2
1Institute for Marine and Antarctic Studies, University Of Tasmania, Hobart, Australia, 2Centre for Marine Socioecology, University of Tasmania, Hobart, Australia
Species redistributions and warming temperatures are occurring in most coastal marine ecosystems, generating a need to understand and predict ecological, fisheries and socio-economic consequences of these changes. Multi-species and ecosystem models are commonly used as tools to support these needs and marine management decisions, yet we still lack a general and well-tested approach to represent dynamic changes in species composition. Here, we explore potential consequences of species redistributions on local communities using a multi-species size spectrum model developed for the south-east Australian coastal rocky reef ecosystem. South-east Australia is one of the fastest warming marine ecosystems globally and has some of the highest numbers recorded of shifting species. It is also one of the best-studied coastal regions with routine monitoring surveys going back to early 1990s. Size spectrum models provide a relatively simple yet physiologically structured mechanistic way to model ecological systems, where species interactions largely depend on size, and feeding, growth and reproduction emerge dynamically. We trial three alternative approaches for exploring the community-level consequences of species redistributions: i) dynamically forcing the model with changes in species’ spatial overlap, ii) incorporating local changes in temperature that influence reproductive efficiency and growth, and iii) explicitly introducing new species into the system during the course of the simulation. We evaluate the feasibility, and ecological accuracy of these approaches and compare the predicted outcomes.
Asta Audzijonyte is a research fellow in macroecological modelling at the Institute for Marine and Antarctic Studies. She has an interdisciplinary research background in evolutionary biology, ecological modelling and molecular ecology. Her current research focuses on understanding how human induced changes in growth and reproductive schedules of marine organisms (life-histories) and redistributions of species are affecting marine ecosystem function, productivity and resilience.