Scott D. Ling

University of Tasmania · Institute for Marine and Antarctic Studies (IMAS)

Sea urchins have the capacity to destructively overgraze kelp beds and cause a wholesale shift to an alternative and stable ‘urchin barren’ reef state. However, destructive grazing appears labile and contingent on behavioural shift. Changes in supply of allochthonous ‘drift-kelp’ food are hypothesised as a trigger of change in urchin grazing behavi...

Ocean warming, ocean acidification and overfishing are major threats to the structure and function of marine ecosystems. Driven by increasing anthropogenic emissions of CO 2 , ocean warming is leading to global redistribution of marine biota and altered ecosystem dynamics, while ocean acidification threatens the ability of calcifying marine organis...

Competition for space between corals and macroalgae represents a key threatening process for coral reefs, yet the influence of climate change on this competitive interaction is poorly understood, particularly at the poleward margins of coral distribution. Here we describe the discovery of Australia’s southernmost hermatypic corals and explore novel...

Across many temperate coastlines worldwide, kelp habitat has degraded to be replaced by alternative reef‐states with consequences to ecosystem functioning. Identifying both causes of decline and mechanisms of resilience of remnant kelp habitat is critical for managing and restoring these ecosystems. We use a combination of aerial imagery and field...

Echinoderms are a common component of benthic marine ecosystems, with many being ecologically and/or economically important. Like many marine organisms, most echinoderms have a bipartite life history with a planktonic larval phase and a benthic adult phase. The transition between these phases (i.e. settlement) is complex and comprises a cascade of...

Ecosystem structure and function are increasingly threatened by changing climate, with profound effects observed globally in recent decades. Based on standardized visual censuses of reef biodiversity, we describe 27 years of community-level change for fishes, mobile macroinvertebrates and macroalgae in the Tasmanian ocean-warming hotspot. Significa...

Warming seas, marine heatwaves, and habitat degradation are increasingly widespread phenomena affecting marine biodiversity, yet our understanding of their broader impacts is largely derived from collective insights from independent localized studies. Insufficient systematic broadscale monitoring limits our understanding of the true extent of these...

In this chapter we describe the approaches available for kelp restoration and emphasize that you will need to consider the best suited approach(es) for your particular project (Fig. 5.1). The selected methodology will depend on the expertise of your group, project budget, the stressors present, environmental conditions, and whether kelp can return...

Effective prioritisation of research and conservation action for threatened species requires understanding the relative importance of the various pressures they face. This can be difficult for rare, cryptic, and data-deficient species, particularly when drivers of population decline are complex and indirectly impact one another. We developed a risk...

One of the most pronounced effects of climate change on the world's oceans is the (generally) poleward movement of species and fishery stocks in response to increasing water temperatures. In some regions, such redistributions are already causing dramatic shifts in marine socioecological systems, profoundly altering ecosystem structure and function,...

Changing biodiversity alters ecosystem functioning in nature, but the degree to which this relationship depends on the taxonomic identities rather than the number of species remains untested at broad scales. Here, we partition the effects of declining species richness and changing community composition on fish community biomass across >3000 coral a...

Abstract. Crown-of-thorns sea stars (Acanthaster sp.) are among the most studied coral reef organisms, owing to their propensity to undergo major population irruptions, which contribute to significant coral loss and reef degradation throughout the Indo-Pacific. However, there are still important knowledge gaps pertaining to the biology, ecology, an...

Climate change is transforming coral reef structures, with important yet largely unknown consequences for reef food webs. Crustaceans, molluscs, polychaetes, and other small motile invertebrates living as epifauna on coral habitats represent an essential trophic link between primary producers and a diverse and abundant invertivorous fish fauna. Her...

Improved public understanding of the ocean and the importance of sustainable ocean use, or ocean literacy, is essential for achieving global commitments to sustainable development by 2030 and beyond. However, growing human populations (particularly in mega-cities), urbanisation and socio-economic disparity threaten opportunities for people to engag...

Primary productivity of marine ecosystems is largely driven by broad gradients in environmental and ecological properties. By contrast, secondary productivity tends to be more variable, influenced by bottom-up (resource-driven) and top-down (predatory) processes, other environmental drivers, and mediation by the physical structure of habitats. Here...

Primary productivity of marine ecosystems is largely driven by broad gradients in environmental and ecological properties. In contrast, secondary productivity tends to be more variable, influenced by bottom-up (resource driven) and top-down (predatory) processes, other environmental drivers, and mediation by the physical structure of habitats. Here...

Changes in invertebrate body size-distributions that follow loss of habitat-forming species can potentially affect a range of ecological processes, including predation and competition. In the marine environment, small crustaceans and other mobile invertebrates ('epifauna') represent a basal component in reef food webs, with a pivotal secondary prod...

Corallivorous crown-of-thorns starfishes (Acanthaster spp.) can decimate coral assemblages on Indo-Pacific coral reefs during population outbreaks. While initial drivers of population irruptions leading to outbreaks remain largely unknown, subsequent dispersal of outbreaks appears coincident with depletion of coral prey. Here, we used in situ time-...

Reef Life Survey (RLS) provides a new model for ecological monitoring through training experienced recreational divers in underwater visual census methods to the level of skilled scientists. Detail produced is similar to that of programs with professional scientific teams, at low cost to allow global coverage. RLS differs from most other citizen sc...

Marine ecosystems are structured by an array of natural and anthropogenic drivers, their diverse influences varying between different community types and across space. We assessed consistency in variation in composition and richness for three communities (macro- and meio-faunal communities associated with macroalgae, and soft-sediment infaunal comm...

Anthropogenic drivers are flattening reef structure from 3-dimensional habitats composed of macroalgae and live branching corals towards low-profile turfing algae. Our current understanding of the consequences of widespread reef degradation currently fails to consider the responses of small mobile invertebrates (‘epifauna’) to patterns of change am...

Many predators reported to feed on crown-of-thorns starfish (CoTS, Acanthaster spp.) are generalist and opportunistic feeders. However, research into predation on CoTS tends to examine these predator–prey interactions in isolation, and it remains unknown whether many potential predators will prey on CoTS when other, potentially more palatable, food...

Experimental exclusion of marine herbivores is a powerful approach to reveal their effects on the structure and function of ecosystems. However, such manipulations can be logistically challenging, particularly for subtidal reef systems. Here we report novel observations of a natural barrier to grazing sea urchins formed by the octocoral Erythropodi...

Opposing bottom-up ‘resource-driven’ and top-down ‘consumer-driven’ forces interact to shape the structure of ecosystems. While these counteracting forces are well recognised, debate remains regarding which of these forces is more influential across space and time. Here we explore bottom-up versus top-down control of macroalgal communities for temp...

Climate change poses significant emerging risks to biodiversity, ecosystem function and associated socioecological systems. Adaptation responses must be initiated in parallel with mitigation efforts, but resources are limited. As climate risks are not distributed equally across taxa, ecosystems and processes, strategic prioritization of research th...

There is growing empirical evidence around the world demonstrating regime shifts of marine ecosystems. But generalizable criteria to detect and define regime shifts are elusive because of: (i) an incomplete scientific understanding of processes underlying regime shifts; (ii) because the baseline state and conditions are ill defined, and; (iii) due...

The ability of sea urchins to overgraze kelp beds yet avoid “eating themselves out of house and home” appears owing to their ability to switch diet from nutritious kelp beds to filamentous/encrusting algae; that is, body condition, growth, and longevity of urchins decline upon collapse of kelp beds to barren grounds. However, despite lower individu...

Biogenic marine habitats are threatened by a multitude of human stressors, and urbanised temperate coasts in particular are exposed to an intense and accumulating range of impacts. Here we use a 3-way factorial design to test the individual and combined effects of an approximate doubling of nutrients, sedimentation and sea urchin herbivory on rocky...

Climate change is leading to shifts in species geographical distributions, but populations are also probably adapting to environmental change at different rates across their range. Owing to a lack of natural and empirical data on the influence of phenotypic adaptation on range shifts of marine species, we provide a general conceptual model for unde...

Sea urchin grazing can result in regime shift from productive kelp beds to sea urchin barren grounds that represent an alternative and stable reef state. Here we examine the stability of urchin barrens by defining the demographics of the Australian urchin Heliocidaris erythrogramma during regime shift to, and maintenance of, barrens. Inverse‐logist...

NON-TECHNICAL SUMMARY The abundance of Centrostephanus and the extent of its impact on kelp beds in eastern Tasmania was re-surveyed by divers and underwater towed-video in 2016/17 and assessed relative to baselines established in 2001/02. The re-survey involved 156 diver transects spanning 13 eastern Tasmanian sites spaced ~20 km from Eddystone Po...

Understanding the strength and type of interactions among species is vital to anticipate how ecosystems will respond to ongoing anthropogenic stressors. Here, we examine the ecological function of native (Ecklonia radiata) and invasive (Undaria pinnatifida) kelps in resisting shifts to sediment-trapping turf on reefs within the highly urbanized tem...

Caribbean reefs have suffered decline in coral cover in recent decades due to recurrent anthropogenic and natural stressors. The regional collapse of the sea urchin Diadema antillarum, combined with overfishing, has contributed to a phase-shift of coral reef communities towards fleshy macroalgal dominance. Here, we examine the population dynamics o...

Adapting to climate change is contingent on an ability to adjust before opportunity is lost. Given that research funding to understand adaptation is limited, rapid return on investment is critical. For Australian marine environments, climate-change impacts are well documented and adaptation opportunities have been identified across aquaculture, fis...

Surface waters off eastern Tasmania are a global warming hotspot. Here, mean temperatures have been rising over several decades at nearly four times the global average rate, with concomitant changes in extreme temperatures – marine heatwaves. These changes have recently caused the marine biodiversity, fisheries and aquaculture industries off Tasman...

The movement capacity of the crown-of-thorns starfishes (Acanthaster spp.) is a primary determinant of both their distribution and impact on coral assemblages. We quantified individual movement rates for the Pacific crown-of-thorns starfish (Acanthaster solaris) ranging in size from 75–480 mm total diameter, across three different substrates (sand,...

[This corrects the article DOI: 10.1093/biosci/biw180.].

Coral-eating crown-of-thorns starfish (Acanthaster sp.) often exhibit dramatic population outbreaks, suggesting that their local abundance may be relatively unchecked by predators. This may be due to high concentrations of anti-predator chemicals (saponins and plancitoxins), but the effectiveness of chemical deterrents in protecting Acanthaster sp....

Reporting progress against targets for international biodiversity agreements is hindered by a shortage of suitable biodiversity data. We describe a cost-effective system involving Reef Life Survey citizen scientists in the systematic collection of quantitative data covering multiple phyla that can underpin numerous marine biodiversity indicators at...

Supplementary data are available at BIOSCI online.

Predatory release has long been considered a potential contributor to population outbreaks of crown-of-thorns starfish (CoTS; Acanthaster spp.). This has initiated extensive searches for potentially important predators that can consume large numbers of CoTS at high rates, which are also vulnerable to over-fishing or reef degradation. Herein, we rev...

Shifts from productive kelp beds to impoverished sea urchin barrens occur globally and represent a wholesale change to the ecology of sub-tidal temperate reefs. Although the theory of shifts between alternative stable states is well advanced, there are few field studies detailing the dynamics of these kinds of transitions. In this study, sea urchin...

Data used in analyses. (XLSX)

Significance Kelp forests support diverse and productive ecological communities throughout temperate and arctic regions worldwide, providing numerous ecosystem services to humans. Literature suggests that kelp forests are increasingly threatened by a variety of human impacts, including climate change, overfishing, and direct harvest. We provide the...

The method detailed here was designed to provide a step-by-step guide to the extraction and quantification of microplastics (defined as plastic particles smaller than 5mm but larger than 1μm) from benthic sediment samples. The methods described here were determined after reviewing the microplastic literature and trialing a number of the reported me...

Remote underwater vehicles are cutting-edge tools for mapping benthic habitats, yet their reliability for detecting patterns in abundance of benthic species remains largely unexplored. Here, we use a stereo-imaging AUV to investigate changes in abundance of the overgrazing sea urchin, Centrostephanus rodgersii, which has undergone climate driven ra...

Climate-driven incursion of the long-spined sea urchin (Centrostephanus rodgersii) in eastern Tasmania has prompted calls for strong management intervention given the urchins' capacity to overgraze kelp beds and cause local collapse of valuable reef fisheries. We examined the effectiveness of commercial divers culling C. rodgersii while undertaking...

The REEF project was established to examine the effect of sea urchins and potential anthropogenic stressors (sediment and nutrients) associated with urbanisation on the local and system-wide dynamics of rocky reefs in Port Phillip Bay (PPB), Victoria. The project explicitly addressed implications for management of resilience of PPB reefs. The REEF...

Long-term shifts in environmental conditions driven by climate change are predicted to persistently modify the distribution of a multitude of species. These range shifts can have significant effects on the functioning of ecological communities. Ocean warming along the southeast coast of Australia has seen a polewards shift in the distribution of th...

A pronounced, widespread and persistent regime shift among marine eco-systems is observable on temperate rocky reefs as a result of sea urchin overgrazing. Here, we empirically define regime-shift dynamics for this grazing system which transitions between productive macroalgal beds and impoverished urchin barrens. Catastrophic in nature, urchin ove...

A pronounced, widespread and persistent regime shift among marine ecosystems is observable on temperate rocky reefs as a result of sea urchin overgrazing. Here, we empirically define regime-shift dynamics for this grazing system which transitions between productive macroalgal beds and impoverished urchin barrens. Catastrophic in nature, urchin over...

Understanding marine regime shifts is important not only for ecology but also for developing marine management that assures the provision of ecosystem services to humanity. While regime shift theory is well developed, there is still no common understanding on drivers, mechanisms and characteristic of abrupt changes in real marine ecosystems. Based...

We apply qPCR molecular techniques to detect in situ rates of consumption of sea urchins (Centrostephanus rodgersii and Heliocidaris erythrogramma) by rock lobsters (Jasus edwardsii). A non-lethal method was used to source faecal samples from trap-caught lobsters over two years within two no-take research reserves. There was high variability in the...

While they can be useful tools to support decision-making in ecosystem management, robust simulation models of ecosystems with alternative states are challenging to build and validate. Because of the possibility of alternative states in model dynamics, no trivial criteria can provide reliable and useful metrics to assess the goodness-of-fit of such...

ABSTRACT: The northern Pacific seastar, Asterias amurensis (Lütken), is an invasive species established throughout the Derwent Estuary, southeast Tasmania. Here we report on field observations of predation on the seastar within its new environment. The spider crab Leptomithrax gaimardii (family Majidae), which characteristically aggregates in shall...

The barrens-forming sea urchin Centrostephanus rodgersii (Diadematidae) has undergone recent poleward range-extension to the Tasmanian coastline (SE Australia). By compiling field observations (including SST spanning >60yrs), broad-scale surveys and manipula-tive experiments conducted during the past decade, this review details knowledge on the res...

ABSTRACT: Overgrazing by sea urchins on temperate reefs can affect a phase shift from macro - algal beds to ‘barrens’ habitat largely devoid of seaweeds. Existing models of barrens formation are derived largely from observations of strongylocentrotid urchins, which typically show a behavioural shift from cryptic feeding to exposed grazing fronts th...

Spatial closures in the marine environment are widely accepted as effective conservation and fisheries management tools. Given increasing human-derived stressors acting on marine ecosystems, the need for such effective action is urgently clear. Here we explore mechanisms underlying the utility of marine reserves to reinstate trophic dynamics and to...