Climate change cascades: Shifts in oceanography, species' ranges and subtidal marine community dynamics in eastern Tasmania

By Craig R. Johnson, S. Banks, Neville Barrett, F. Cazassus, P. Dunstan, G. Edgar, S. Frusher, C. Gardner, M. Haddon, F. Helidoniotis and 18 more. 2011

662 citations recorded by the source corpus.

Abstract Several lines of evidence show that ocean warming off the east coast of Tasmania is the result of intensification of the East Australian Current (EAC). Increases in the strength, duration and frequency of southward incursions of warm, nutrient poor EAC water transports heat and biota to eastern Tasmania. This shift in large-scale oceanography is reflected by changes in the structure of nearshore zooplankton communities and other elements of the pelagic system; by a regional decline in the extent of dense beds of giant kelp ( Macrocystis pyrifera ); by marked changes in the distribution of nearshore fishes; and by range expansions of other northern warmer-water species to colonize Tasmanian coastal waters. Population-level changes in commercially important invertebrate species may also be associated with the warming trend. Over-grazing of seaweed beds by one recently established species, the sea urchin Centrostephanus rodgersii , is causing a fundamental shift in the structure and dynamics of Tasmanian rocky reef systems by the formation of sea urchin ‘barrens’ habitat. Formation of barrens represents an interaction between effects of climate change and a reduction in large predatory rock lobsters due to fishing. Barrens realize a loss of biodiversity and production from rocky reefs, and threaten valuable abalone and rock lobster fisheries and the local economies and social communities they support. This range-extending sea urchin species represents the single largest biologically mediated threat to the integrity of important shallow water rocky reef communities in eastern Tasmania. In synthesizing change in the physical ocean climate in eastern Tasmania and parallel shifts in species' distributions and ecological processes, there is evidence that the direct effects of changing physical conditions have precipitated cascading effects of ecological change in benthic (rocky reef) and pelagic systems. However, some patterns correlated with temperature have plausible alternative explanations unrelated to thermal gradients in time or space. We identify important knowledge gaps that need to be addressed to adequately understand, anticipate and adapt to future climate-driven changes in marine systems in the region.

Subfields: Ecology, Oceanography

View Paper: https://www.semanticscholar.org/paper/162b07dd0eef6386626ab4121d5a05fff9a8c4c8

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Citations in the corpus

Sea urchin barrens as alternative stable states of collapsed kelp ecosystems (2014, neutral): “%) mass (g) (kg m–2) Alaska, USA Exp 72 16 1.81a 0.41a 77 25 − Konar & Estes (2003) California, USA Obs 14 2−3 2.81a 0.4−0.61a 82b 200 0.2−0.6 Dean et al. (1984), Dayton et al. (1992) Chile Obs 36 20−28 − − − − − Vásquez et al. (2006) Nova Scotia, Obs, Exp 31−65 − 1.5−3.2c 0.15−0.25 91b 49 2.0−5.0 B”
Global patterns of kelp forest change over the past half-century (2016, background): “, Bassian ecoregion, Gulf of Maine, Scotian Shelf) (32, 33) and increases where water temperatures are cooling (e.”
Tropicalisation of temperate reefs: Implications for ecosystem functions and management actions (2019, background): “Importantly, however, losses of temperate seaweed forests will have negative consequences for many economically important temperate species such as abalone (Serisawa, Imoto, Ishikawa, & Ohno, 2004), lobster (Johnson et al., 2011) and fish (Yamasaki et al., 2014).”
Variation in the morphology, reproduction and development of the habitat-forming kelp Ecklonia radiata with changing temperature and nutrients (2013, background): “…which is impacting sub - tidal kelp forests in Tasmania (Johnson et al. 2005, Ling et al. 2009a,b), and range shifts in a number of macroalgae (Wernberg et al. 2011) including the contraction and reduction in canopy cover of giant kelp Macrocystis pyrifera in Tasmania (Johnson et al. 2011).”
The role of kelp species as biogenic habitat formers in coastal marine ecosystems (2017, background): “…loss of biogenic 752 habitat from temperate ecosystems, in extreme cases causing phase-shifts from structurally complex 753 habitat to depauperate “barrens” (Breen and Mann, 1976b; Filbee-Dexter and Scheibling, 2014; 754 Hagan, 1983; Johnson et al., 2011; Ling et al., 2015; Steneck et al., 2002).”
Cascading climate change impacts and implications (2020, background): “…to cascades, traversing ecosystems dynamics and their intersection with human-environment systems (Blenckner et al., 2015; Carey et al., 2017; Johnson et al., 2011), multiple hazard cascades, tipping points of harm, thresholds and surprise (Gill and Malamud, 2016; Walker et al., 2009),…”
Climate-driven range expansion of the red-tide dinoflagellate Noctiluca scintillans into the Southern Ocean (2012, background): “This extension of the EAC has facilitated the transportation of a range of marine taxa southward into Tasmanian waters, including phytoplankton (Hallegraeff, 2010), zooplankton (Johnson et al., 2011), invertebrates (Ling et al., 2009) and coastal fish (Last et al., 2011).”