Mr Albert Pessarrodona1, Dr Dan Smale2, Dr Andrew Foggo3, A/Prof Thomas Wernberg1
1University Of Western Australia, Perth, Australia, 2The Marine Biological Association of the UK, Plymouth, UK, 3University of Plymouth, Plymouth, UK
Contemporary climate change is reorganizing the composition of ecological communities by inducing species migrations (range shifts), with migrant thermally-tolerant species often becoming competitively dominant over species with colder affinities. Although these climate-driven changes in species abundance and diversity are well documented, their ecosystem-level implications are poorly understood, and resolving whether reconfigured communities can maintain fundamental ecosystem functions represents a pressing challenge in an increasingly warmer world.
In this talk, I will draw from two case studies from different biogeographic transition zones to demonstrate the ecological impacts of climate-driven shifts and abundance changes of marine foundation species. Specifically, I will focus on how new compositional configurations of marine forests affect ecosystem processes associated with carbon and nutrient cycling (biomass production, detritus flow, herbivory, decomposition).
The expansion and increase of a warm-temperate kelp into areas previously dominated by a cold-affinity congener has prompted a shift in the quantity, quality and timing of trophic subsidies, which suggests shifts in organic matter circulation along large sections of NE Atlantic coastline. Increases in seawater temperature, the frequency of heatwaves and the arrival of tropical herbivores have transformed warm-temperate Australian forests. These are now largely dominated by algal turfs, which support a larger guild of tropical herbivorous fish but manifest reduced trophic connectivity to other habitats.
These studies provide valuable insights for assessing the vulnerability of temperate marine forest communities to global warming, and evidence the critical conservation decisions we will have to make as ecosystems continue their transition into new configurations in the Anthropocene.
Albert is currently undertaking a PhD at the University of Western Australia looking at kelp forest resilience to climate change. He has previously worked in the UK and the Mediterranean