Posted By
ARC Centre of Excellence for Coral Reef Studies
James Cook University Townsville
Queensland 4811 Australia
Phone: 61 7 4781 4000
Email: info@coralcoe.org.au
“It is time to move beyond this simple metric for greater ecological insight.”
In this week’s Ecology paper we outline a revolutionary new way to describe how corals occupy and use space.
The standard approach for describing a species depth preference is its depth range; that is the difference between the shallowest and deepest records of the species.
Our work suggests this standard approach is overly simplistic and offers limited ecological insight because most coral species have a broad depth range.
One of the most prominent features on coral reefs is a strong and consistent zonation of coral assemblage with depth. Predictable groups of species occupy discreet depths over a broad geographic range. This shouldn’t happen if species are more ‘generalist’ with their depth range.
We explored this paradox by modelling the abundance distributions for 110 coral species over a 45 m depth range in Kimbe Bay, Papua New Guinea. These models estimated two metrics to capture how a species uses space; peak depth (the depth at which the species is most abundant) and niche breadth (the depth over which the abundance remains at more than 50% of the maximum abundance). These models allow for an infinite number of ways to describe the way a species uses depth.
More than 85% of species occupy more than 50% of the available depth range when using the traditional metric of depth range. These corals can be considered depth-generalists.
However, when using modelled abundance distributions, only 19% of species span more than 50% of the available depth range.
Our work resolves the paradox by demonstrating that most species are actually depth specialists.
This ecological insight, gained by using this new approach, is further illustrated when comparing estimates for the number of species likely to be able to use deeper areas of the reef as a refuge from disturbances that disproportionately affect corals in the shallows—such as bleaching and cyclones. We call this the ‘the deep reef refugia hypothesis’.
So, based on depth range, 70% of coral species are found at both vulnerable (0–10 m) and potential refuge (>30 m) depths.
In contrast, only 40% of species have a refuge in depth when using the modelled niche breadth of the species.
Depth range is a trait that has been used to predict the vulnerability of species to climate change, the dispersal capacity of a species, and as a proxy for environmental tolerance. Our work suggests it is time to move beyond this simple metric for greater ecological insights.
PAPER: Roberts T, Bridge T, Caley M, Madin J, Baird A (2019). Ecology. ‘Resolving the depth zonation paradox in reef-building corals’. DOI: http://dx.doi.org/10.1002/ecy.2761
Scientists say outdated assumptions around gender continue to hinder effective and fair policymaking and action for climate mitigation and adaptation. Lead author of a new study, Dr Jacqueline Lau
For the first time, scientists have assessed how many corals there are in the Pacific Ocean—and evaluated their risk of extinction. While the answer to “how many coral species are there?” is
Scientists have discovered a never-before-seen biodiversity pattern of coral reef fishes that suggests some fishes might be exceptionally vulnerable to environmental change. A new study shows plank
Scientists say stable seafood consumption amongst the world’s poorer coastal communities is linked to how local habitat characteristics influence fishing at different times of the year. In the co
Abstract: The vast majority of reef fishes have a life history consisting of a pelagic larval phase of typically 20 to 60 days, followed by larval settlement where they remain through their juvenile a
Abstract: Social networks have been and remain important across the Pacific Islands, and beyond, for building and maintaining social-ecological resilience. However, there is little quantitative infor
Abstract: The global conservation community is comprised of a range of organisations, processes, and professionals. Given the diversity of these actors, and the complexity of the systems that conser
Abstract: Seasons create a rhythm in nature and, by extension, in the lives of people who depend directly on natural resources. However, our understanding of how seasons affect the ways that people
Abstract: Oceanic shark populations have declined 77% over the past 60 years as a result of overexploitation in fisheries. However, sustainable shark management is limited to a few developed nations
Abstract: Vertigo3 is a new class of small, fast and agile ‘true-flight’ underwater glider, purposely designed for robotic, artificial intelligence-assisted broadscale marine surveys, and capable
Abstract: Recurrent marine heat waves are leading to widespread coral bleaching, transforming the structure and function of tropical coral reefs. Past bleaching events have highlighted large variatio
Abstract: Shallow-water tropical seascapes typically include a range of habitat types such as coral reefs, mangroves, macroalgal and seagrass beds. These habitats can occur in close proximity and are
ARC Centre of Excellence for Coral Reef Studies
James Cook University Townsville
Queensland 4811 Australia
Phone: 61 7 4781 4000
Email: info@coralcoe.org.au