y A central question in contemporary ecology is how climate change will alter ecosystem structure and function across scales of space and time. Climate change has been shown to alter ecological patterns from individuals to ecosystems, often with negative implications for ecosystem functions and services. Furthermore, as climate change fuels more frequent and severe extreme climate events (ECEs) like marine heatwaves (MHWs), such acute events become increasingly important drivers of rapid ecosystem change. However, our understanding of ECE impacts is hampered by limited collection of broad scale in situ data where such events occur. In 2011, a MHW known as the Ningaloo Nino bathed the west coast of Australia in waters up to 4 degrees C warmer than normal summer temperatures for almost 2 months over 1000s of kilometers of coastline. We revisit published and unpublished data on the effects of the Ningaloo Nino in the seagrass ecosystem of Shark Bay, Western Australia (24.6-26.6 degrees S), at the transition zone between temperate and tropical seagrasses. Therein we focus on resilience, including resistance to and recovery from disturbance across local, regional and ecosystem-wide spatial scales and over the past 8 years. Thermal effects on temperate seagrass health were severe and exacerbated by simultaneous reduced light conditions associated with sediment inputs from record floods in the south-eastern embayment and from increased detrital loads and sediment destabilization. Initial extensive defoliation of Amphibolis antarctica, the dominant seagrass, was followed by rhizome death that occurred in 60-80% of the bay's meadows, equating to decline of over 1,000 km(2) of meadows. This loss, driven by direct abiotic forcing, has persisted, while indirect biotic effects (e.g., dominant seagrass loss) have allowed colonization of some areas by small fast-growing tropical@species (e.g., Halodule uninervis). Those biotic effects also impacted multiple consumer populations including turtles and dugongs, with implications for species dynamics, food web structure, and ecosystem recovery. We show multiple stressors can combine to evoke extreme ecological responses by pushing ecosystems beyond their tolerance. Finally, both direct abiotic and indirect biotic effects need to be explicitly considered when attempting to understand and predict how ECEs will alter marine ecosystem dynamics.
1.Univ Western Australia, Sch Biol Sci, Crawley, WA, Australia 2.Univ Western Australia, Oceans Inst, Crawley, WA, Australia 3.Elizabeth Moore Int Ctr Coral Reef Res & Restorat, Mote Marine Lab, Summerland Key, FL USA 4.Western Australian State Dept Biodivers Conservat, Kensington, WA, Australia 5.Edith Cowan Univ, Ctr Marine Ecosyst Res, Joondalup, WA, Australia 6.Edith Cowan Univ, Sch Sci, Joondalup, WA, Australia 7.Deakin Univ, Ctr Integrat Ecol, Sch Life & Environm Sci, Warrnambool, Vic, Australia 8.Nova Southeastern Univ, Guy Harvey Res Inst, Save Our Seas Shark Ctr, Ft Lauderdale, FL 33314 USA 9.Dept Water & Environm Regulat, Perth, WA, Australia 10.Univ Western Australia, Oceans Inst, Oceans Grad Sch, Crawley, WA, Australia 11.Florida Int Univ, Dept Biol Sci, Ctr Coastal Oceans Res, Miami, FL 33199 USA 12.Coll William & Mary, Virginia Inst Marine Sci, Williamsburg, VA USA
Recommended Citation:
Kendrick, Gary A.,Nowicki, Robert J.,Olsen, Ylva S.,et al. A Systematic Review of How Multiple Stressors From an Extreme Event Drove Ecosystem-Wide Loss of Resilience in an Iconic Seagrass Community[J]. FRONTIERS IN MARINE SCIENCE,2019-01-01,6