Recommendations for maintaining functioning of the Great Barrier Reef
Led by: Prof Peter Mumby, UQ
The Great Barrier Reef is experiencing increased environmental stress which threatens its functioning. Yet a subset of species are often disproportionately important in maintaining a functioning ecosystem. This project harnesses Queensland’s breadth of reef expertise to deliver timely recommendations on what can be done to strengthen and protect key supportive species. Specifically we ask which species – or functional groups of species – drive processes that maintain a healthy reef. We provide a scientific consensus in support of (1) species’ rankings and recommendations for enhanced protection, (2) informed scenarios for what’s at stake: the consequences of not taking further action, and (3) make recommendations for targeted R&D. We will also suggest activities that can be undertaken by citizen science organisations to help monitor the status of priority species or identify areas of either outstanding value or threat.
Climate change exacerbates local stressors on coral reefs and threatens the very functioning of the Great Barrier Reef. We can think of a functioning ecosystem as one that resembles its natural state and is able to support key ecosystem goods and services such as maintaining biodiversity, productive fisheries, and coastal protection from storms. While authorities employ a diversity of approaches to manage the reef, it is important to ask whether key functions are adequately protected.
It has long been recognised that some species are more important than others (Paine 1966, 1980) and this notion is embedded in concepts like “ecosystem engineers” (species that build ecosystems) and “keystone species” (species whose impact on others is disproportionately high). While healthy and productive ecosystems typically require high overall biodiversity, hundreds of studies have highlighted the critical importance played by a small subset of species (Hooper et al 2005). This means that biodiversity conservation – which is often based on habitat protection – often needs to complement its strategy with specific provisions for key species. For example, the rezoning of the GBR in 2005 was motivated, in part, by a requirement to protect marine biodiversity. Implementation of the zoning plan continues to have multiple benefits (McCook et al 2010), but the question remains whether zoning might be augmented with additional management provisions targeted at a small, but critically important, subset of species. Answering this question is becoming increasingly important given the strengthening impacts of climate change and ocean acidification, which exacerbate local chronic stressors including poor water quality.
Coral reefs are complex ecosystems with multiple players including microbes, plankton, algae, corals, sponges, mobile invertebrates, and fish (Fig. 1). Collectively, these species support the reef’s ‘life support system’ which includes critical functions such as calcification, reef accretion (reef building), bioerosion, primary production, herbivory, tertiary production, and nutrient cycling. For example, corals are major contributors to calcification and reef building, but not all corals contribute to the same extent (Perry et al 2012; Kennedy et al 2013). Some species contribute disproportionately to the recovery and coverage of corals, such as table Acropora (Ortiz et al 2014), whereas others contribute disproportionately to rates of reef building, such as the sediment-tolerant genus Turbinaria (Morgan et al 2016). These roles are not confined to corals. Microbial processes underpin many ecosystem processes, mobile invertebrates (e.g., crabs, molluscs) are a key driver of fisheries productivity (tertiary production), planktivorous fishes capture nutrients in upwelling zones, some ‘herbivorous’ fishes are more important than others in controlling fouling seaweeds, and so on. Yet when ecosystem processes get out of balance the results can sometimes be surprising and often undesirable. Examples include harmful plankton blooms, seaweed-dominated reefs that struggle to recover, and outbreaks of coral disease.
This project seeks to identify those subsets of species that drive critical ecosystem functioning. The project’s principal objectives are:
1) Identify and rank (to the extent possible) those species (or functional groups of species) that drive functioning coral reefs
2) Describe any threats to such species and rank their severity
3) Generate scenarios for “what’s at stake”: how will ecosystems change if these species are allowed to decline and how will that affect stakeholders?
4) Consider the degree to which threats could be reduced through management actions (e.g., declarations of species protection, harvest controls, etc.)
5) Report and discuss recommendations with decision-makers
6) Identify critical knowledge gaps and recommend priority research questions
7) Recommend and discuss a set of actions for citizen science groups such that data can be acquired to support the monitoring of priority species
Operationally, the project will adopt the highly successful approach to problem synthesis pioneered by the US National Center for Ecological Analysis and Synthesis. A working group of scientists will meet several times and a dedicated post-doctoral researcher will be tasked with undertaking data collation, synthesis, and reporting. Working group meetings will be augmented by a series of further working group activities. This will likely include tasking sub working groups to explore priority questions in more detail and may include additional sub-contracts to several working group members. We also anticipate generating a list of priority R&D projects that resolve critical knowledge gaps. These projects might be considered for subsequent NESP funding.
The project team includes more than 20 scientists drawn from a range of disciplines and with diverse taxonomic interests. Their collective experience will make for a thoughtful response to the questions posed. Moreover, we will take advantage of complementary national and international expertise. Nationally, we will consult with representatives from the NESP Threatened Species and Marine Biodiversity hubs who collectively have principles for evaluating species’ threats and rationale for considering ecosystem functioning. Internationally, we will invite Dr David Obura, Chair of the International Union for the Conservation of Nature (IUCN) Red list panel for coral reefs, who have previously undertaken processes to list threatened reef species. We also retain the option to invite one or two international experts to supplement our expertise.
The project will be managed by Professor Peter Mumby at the University of Queensland. There are several reasons for this. First, Mumby is also coordinating the proposed NESP project, ‘Guidance System for Resilience-based Management of the GBR’ which will benefit from the focus here on species’ functions. Information on key reef species will inform the analyses of reef resilience and identification of ecologically valuable reefs. Second, as an ecosystem ecologist, Mumby’s own research has considered a wide range of ecosystem functions as well as the impacts of reef management. Examples include the processes of reef primary productivity, herbivory, food web functioning, role of habitat complexity, effects of predators, nursery habitat functions, roles of larval connectivity, bioerosion, demographic and food web implications of climate change, fisheries regulations, marine reserve design, and processes of resilience. Thus, Mumby’s approach is to consider all functional groups rather than focus specifically one a preferred group. Third, Mumby has contributed to the wider discussion of managing ecosystem functioning and services through his participation as an advisor to the UN IPBES (Inter-governmental Platform for Biodiversity and Ecosystem Services), advisor to the Australian Bureau of Statistics ecosystem accounting for the Great Barrier Reef, and also chief investigator of the World Bank project “Capturing Coral Reef Ecosystem Services” which develops tools specifically to manage reef ecosystem functioning.
This project builds on a broad research base, which was recently reviewed by Mumby’s lab team (Harborne AR, Rogers A, Bozec Y-M, Mumby PJ (2017) Multiple stressors and the functioning of coral reefs. Annual Reviews of Marine Science 9:445-468). However, it is vital to pool the broader coral reef expertise of Queensland to seek a consensus and fully balanced analysis of species’ contributions to reef functioning. This is particularly true in fast-moving fields including microbiology.
Governance: Operational management of the project will be steered by a team comprising the project lead, Sheriden Morris (RRRC), Ian Poiner (independent scientist), Damien Burrows (TWQ Hub Leader), and Roger Beeden (GBRMPA). The project is closely aligned with RIMReP in that it advises on priority species for inclusion in monitoring and reconnaissance activities. This will be facilitated by close interaction with multiple GBRMPA staff and Britta Schaffelke as key participants and advisors respectively. Links with the associated project (4.5 Guidance System for Resilience-Based Management) will include several shared team members who have expertise on the impacts of water quality of biological and ecological processes (Ken Anthony, Jane Waterhouse). Discussions with the RIMReP team have resulted in a plan to utilise the RIMReP Integration Committee and/or Steering Committee as the principal avenue for project communication with users. This is an efficient use of everyone’s’ time but will be supplemented as necessary with dedicated face-to-face engagements with individual end users.
NESP 2017 Research Priority Alignment
The project aligns with multiple NESP research priorities.
- Theme 1: (a) Improve knowledge of cumulative stressors (analyses of the effects of cumulative stressors on key species and processes). (b) Evaluate the practicalities of restoring connectivity to freshwater, coastal and marine ecosystems and the resilience of dependent species (identifying the degree to which population connectivity threatens functionally-important species)
- Theme 2: (a) Improve understanding of consequences of climate change (scenarios of reef functioning under climate change); (b) Improve our understanding of the consequences of climate change for the health and resilience of vulnerable freshwater, coastal and marine species, and ecosystems (identify vulnerability of functionally-important species; create scenarios of how functioning will change in the absence of further management). (c) Develop practical, cost-effective, climate change adaptation options that are accessible to the managers of coastal and marine ecosystems and their catchments. (role that additional protection to key species might play in enhancing reef functioning, such as greater recovery from and resistance to disturbance)
- Theme 3: (a) Complements the focus on trialling practical efforts to improve resilience by identifying target species. Identify regionally-specific management interventions (by identifying species that need additional protection); (b) Develop and implement better tools, including spatial information, to support prioritisation of on-ground investments and interventions and assess their success (identify key species to value for their functioning and identify areas where they may experience greater threat); (c) Explore opportunities for citizen science and Indigenous participation (direct link with Citizens of the GBR by advising which species they should focus efforts upon).
- Intent to support RIMReP: Identifies key species for consideration in monitoring and reconnaissance programmes.
Resilience; Ecosystem functioning; Climate change; Outlook; Protection.
This project is jointly funded through UQ, AIMS, JCU and the Australian Government’s National Environmental Science Program.