Scientific Papers & Management ReportsScientific papers & management reports that use RLS data, designed for management, policy & building public knowledge on the state of the world's reefs.
A global assessment of the direct and indirect benefits of marine protected areas for coral reef conservation.
Biodiversity Research (2018)
Aim: Marine protected areas (MPAs) are increasingly implemented to conserve or restore coral reef biodiversity, yet evidence of their benefits for enhancing coral cover is limited and variable.
Location: 30 MPAs worldwide and nearby sites (within 10 km).
Taxa: Cover of key functional groups for coral (total, branching, massive and tabular), and algae (total, filamentous, foliose) and total biomass of reef fish trophic groups (excavator, scraper, browser, higher carnivore).
Methods: We used a global dataset obtained using standardized survey methods at 465 sites associated with 30 MPAs in 28 ecoregions to test the effects of five key MPA attributes (>10 years old, well-enforced, no-take, large and isolated) on coral cover, algal cover and reef fish biomass. We also tested the direct (reducing disturbance by human activities) versus indirect pathways (increasing grazing potential through recovering populations of herbivorous fishes) by which MPAs can influence coral and algal cover.
Results: Only well-enforced, no-take and old (>10 years) MPAs had higher total coral cover (response ratio 1.08–1.19×) than fished sites, mostly due to the increased cover of massive coral growth forms (1.34–2.06×). This effect arose through both the direct influence of protection and indirect benefits of depressed algal cover by recovering herbivorous fish biomass. Neither the direct (standardized coefficient = 0.06) nor indirect effects (standardized coefficient = 0.04) of no-take protection on coral cover were particularly strong, likely reflecting regional differences in fishing gear, targeted species and trophic webs.
Conclusions: MPAs promote the persistence of some functional groups of corals, and thus represent an important management tool, globally.
Reef fish carbonate production assessments highlight regional variation in sedimentary significance.
Study led by UK researchers uses RLS data to work out how much carbonate mud comes from reef fish intestines
Recent studies show that all marine bony fish produce mud-sized (<63 μm) carbonate at rates relevant to carbonate sediment budgets, thus adding to the debate about the often enigmatic origins of fine-grained marine carbonates. However, existing production data are geographically and taxonomically limited, and because different fish families are now known to produce different carbonate polymorphs—an issue relevant to predicting their preservation potential—these limitations represent an important knowledge gap.
Here we present new data from sites in the Western Pacific Ocean, based on an analysis of 45 fish species. Our data show that previously reported production outputs (in terms of rates and family-specific mineralogies) are applicable across different biogeographic regions. On this basis, we model carbonate production for nine coral reef systems around Australia, with production rates averaging 2.1–9.6 g m–2 yr–1, and up to 105 g m–2 yr–1 at discrete sites with high fish biomass.
With projected production rates on lower-latitude reefs up to two-fold higher, these outputs indicate that carbonate production rates by fish can be comparable with other fine-grained carbonate-producing taxa such as codiacean algae. However, carbonates produced by Australian reef fish assemblages are dominated by a highly unstable amorphous polymorph; a marked contrast to Caribbean assemblages in which Mg calcite dominates.
These findings highlight important regional differences in the sedimentary relevance and preservation potential of fish carbonates as a function of historical biogeographic processes that have shaped the world’s marine fish faunas.
- A continuing debate between environmental scientists and fisheries biologists on the sustainability of fisheries management practices, and the extent of fishing impacts on marine ecosystems, is unlikely to be resolved without fishery‐independent data spanning large geographic and temporal scales. Here, we compare continental‐ and decadal‐scale trends in fisheries catches with underwater reef monitoring data for 533 sites around Australia, and find matching evidence of rapid fish‐stock declines.
- Regardless of a high global ranking for fisheries sustainability, catches from Australian wild fisheries decreased by 31% over the past decade. The biomass of large fishes observed on underwater transects decreased significantly over the same period on fished reefs (36% decline) and in marine park zones that allow limited fishing (18% decline), but with a negligible overall change in no‐fishing marine reserves. Populations of exploited fishes generally rose within marine reserves and declined outside the reserves, whereas unexploited species showed little difference in population trends within or outside reserves.
- Although changing climate and more precautionary fisheries management contribute to declining fish catches, fisheries‐independent transect data suggest that excessive fishing also plays a major role.
- The large number of fishery stocks that remain unmanaged or have poor data, coupled with continuing declines in the stock biomass of managed fish species, indicate that Aichi Target 6 of the Convention on Biological Diversity (i.e. ‘by 2020, all fish and invertebrate stocks and aquatic plants are managed and harvested sustainably’) will not be achieved in Australia, or elsewhere.
- In order to maintain some naturally functioning food webs supported by large predators and associated ecosystem services in this era of changing climate, a greatly expanded network of effective, fully protected marine protected areas is needed that encompasses global marine biodiversity. The present globally unbalanced situation, with >98% of seas open to some form of fishing, deserves immediate multinational attention.
Proceedings of the National Academy of Sciences (2018)
Marine reserves that prohibit fishing are a critical tool for sustaining coral reef ecosystems, yet it remains unclear how human impacts in surrounding areas affect the capacity of marine reserves to deliver key conservation benefits. Our global study found that only marine reserves in areas of low human impact consistently sustained top predators. Fish biomass inside marine reserves declined along a gradient of human impacts in surrounding areas; however, reserves located where human impacts are moderate had the greatest difference in fish biomass compared with openly fished areas. Reserves in low human-impact areas are required for sustaining ecological functions like high-order predation, but reserves in high-impact areas can provide substantial conservation gains in fish biomass.
Coral reefs provide ecosystem goods and services for millions of people in the tropics, but reef conditions are declining worldwide. Effective solutions to the crisis facing coral reefs depend in part on understanding the context under which different types of conservation benefits can be maximized. Our global analysis of nearly 1,800 tropical reefs reveals how the intensity of human impacts in the surrounding seascape, measured as a function of human population size and accessibility to reefs (“gravity”), diminishes the effectiveness of marine reserves at sustaining reef fish biomass and the presence of top predators, even where compliance with reserve rules is high. Critically, fish biomass in high-compliance marine reserves located where human impacts were intensive tended to be less than a quarter that of reserves where human impacts were low. Similarly, the probability of encountering top predators on reefs with high human impacts was close to zero, even in high-compliance marine reserves. However, we find that the relative difference between openly fished sites and reserves (what we refer to as conservation gains) are highest for fish biomass (excluding predators) where human impacts are moderate and for top predators where human impacts are low. Our results illustrate critical ecological trade-offs in meeting key conservation objectives: reserves placed where there are moderate-to-high human impacts can provide substantial conservation gains for fish biomass, yet they are unlikely to support key ecosystem functions like higher-order predation, which is more prevalent in reserve locations with low human impacts.
BioTIME: a database of biodiversity time series for the Anthropocene.
Global Ecology and Biogeography (2018)
Fish communities associated with coral reefs worldwide are threatened by habitat degradation and overexploitation. We assessed coral reefs, mangrove fringes, and seagrass meadows on the Caribbean coast of Panama to explore the influences of their proximity to one another, habitat cover, and environmental characteristics in sustaining biomass, species richness and trophic structure of fish communities in a degraded tropical ecosystem. We found 94% of all fish across all habitat types were of small body size (≤10 cm), with communities dominated by fishes that usually live in habitats of low complexity, such as Pomacentridae (damselfishes) and Gobiidae (gobies). Total fish biomass was very low, with the trend of small fishes from low trophic levels over-represented, and top predators under-represented, relative to coral reefs elsewhere in the Caribbean. For example, herbivorous fishes comprised 27% of total fish biomass in Panama relative to 10% in the wider Caribbean, and the small parrotfish Scarus iseri comprised 72% of the parrotfish biomass. We found evidence that non-coral biogenic habitats support reef-associated fish communities. In particular, the abundance of sponges on a given reef and proximity of mangroves were found to be important positive correlates of reef fish species richness, biomass, abundance and trophic structure. Our study indicates that a diverse fish community can persist on degraded coral reefs, and that the availability and arrangement within the seascape of other habitat-forming organisms, including sponges and mangroves, is critical to the maintenance of functional processes in such ecosystems.
Marine Ecology Progress Series (2018)
Fish capture has far-reaching but inadequately assessed implications for marine food webs. At the community level, such effects are typically investigated using dynamic models that rely on partially subjective categorization of species into trophic groups and that mostly overlook the substantial contribution of ontogenetic dietary variation within fish species. Here, we estimate consumption by fish communities at 376 southern Australian sites by applying a recently developed statistical model that predicts diet for individual fish based on their body size and taxonomic identity, with predicted diets then summed to estimate total community consumption. Impacts of fishing and human population density as top-down pressures on shallow reef communities were thereby resolved at fine taxonomic scales. Fishes were estimated to consume 71% more prey biomass in southern Australian no-take marine protected areas (MPAs) relative to fished sites. Consumption of algae and sessile invertebrates was unexpectedly high in MPAs, an outcome not apparent with fish species allocated into pre-defined trophic groups. Extension of this individual size-structured modelling approach provides an opportunity to fill important knowledge gaps in understanding human impacts on marine food webs.
Conservation Biology (2018)
Considerable empirical evidence supports recovery of reef fish populations with fishery closures. In countries where full exclusion of people from fishing may be perceived as inequitable, fishing‐gear restrictions on nonselective and destructive gears may offer socially relevant management alternatives to build recovery of fish biomass. Even so, few researchers have statistically compared the responses of tropical reef fisheries to alternative management strategies. We tested for the effects of fishery closures and fishing gear restrictions on tropical reef fish biomass at the community and family level. We conducted 1,396 underwater surveys at 617 unique sites across a spatial hierarchy within 22 global marine ecoregions that represented 5 realms. We compared total biomass across local fish assemblages and among 20 families of reef fishes inside marine protected areas (MPAs) with different fishing restrictions: no‐take, hook‐and‐line fishing only, several fishing gears allowed, and sites open to all fishing gears. We included a further category representing remote sites, where fishing pressure is low. As expected, full fishery closures, (i.e., no‐take zones) most benefited community‐ and family‐level fish biomass in comparison with restrictions on fishing gears and openly fished sites. Although biomass responses to fishery closures were highly variable across families, some fishery targets (e.g., Carcharhinidae and Lutjanidae) responded positively to multiple restrictions on fishing gears (i.e., where gears other than hook and line were not permitted). Remoteness also positively affected the response of community‐level fish biomass and many fish families. Our findings provide strong support for the role of fishing restrictions in building recovery of fish biomass and indicate important interactions among fishing‐gear types that affect biomass of a diverse set of reef fish families.
Species’ thermal ranges predict changes in reef fish community structure during 8 years of extreme temperature variation.
Diversity and Distributions (2018)
Reef fish community structure can change very quickly when exposed to extreme thermal anomalies, in directions predicted from the realized thermal niche of the species present. Such predictions can thus identify species that will be most responsive to changing ocean climate. Continued warming, coupled with periodic extreme heat events, may lead to the loss of ecosystem services and ecological functions, as mobile species relocate to more hospitable climes, while less mobile species may head towards extinction
realized thermal niches) can be used to predict patterns of occurrence and abundance changes observed during a marine heatwave, relative to other important life history and functional traits.
Location: Rottnest Island, Western Australia.
Methods: A time series of standardized quantitative surveys of reef fishes spanning 8 years of pronounced ocean temperature change is used to test whether accurate predictions on shifts in species occupancy and abundance are possible using species traits.
Results: Species-level responses in occurrence and abundance were closely related to the mid-point of their realized thermal niche, more so than body size, range size or trophic level. Most of the species that disappeared from survey counts during the heatwave were characterized by geographic ranges that did not extend to latitudes with temperatures equivalent to the ocean temperature peak during the heatwave. We thus find support for the hypothesis that current distribution limits are set directly or indirectly by temperature and are highly responsive to ocean temperature variability.
Main conclusions: Our study shows that reef fish community structure can change very quickly when exposed to extreme thermal anomalies, in directions predicted from the realized thermal niche of the species present. Such predictions can thus identify species that will be most responsive to changing ocean climate. Continued warming, coupled with periodic extreme heat events, may lead to the loss of ecosystem services and ecological functions, as mobile species relocate to more hospitable climes, while less mobile species may head towards extinction.
Marine Pollution Bulletin (2018)
Uses RLS fish, invertebrate and photoquadrat data from south eastern Australia to determine the most sensitive reef community indicators of pollution as measured directly at each reef site.
• Concentrations of major pollutants were quantified for 42 Australian reefs.
• Heavy metals and nutrient enrichment appeared most pervasive for reef life.
• Polluted reef assemblages were impoverished and showed reduced ecological function.
• Pollution collapses reef assemblages from long and complicated to short and simple.
Marine Ecology Progress Series (2018)
Predictions of the diet of individual fishes based on their size and family show that the overall consumption by whole fish communities inside marine protected areas (MPAs) differs considerably to predictions for communities outside. The results highlight that sites surveyed by RLS divers in MPAs in SE Australia have a fish community predicted to consume substantially more sponges and small fishes (due to more big fishes and different species recovering in the MPAs).
Global Ecology and Biogeography (2017)
Uses RLS photoquadrat data from around Australia to identify patterns of different reef habitats (e.g. urchin barrens, turfing algae) and how they are influenced by environmental factors.
Nature Ecology & Evolution (2017)
The vast amount of RLS data on reef species’ distributions shows the clear effect of temperature in limiting the range edges of species, and suggest potential limits to thermal adaptation.
Science Advances (2017)
The decline in species richness from the equator to the poles depends on the scale of observation and the local abundance of species. The RLS data on fishes and invertebrates allowed these influences to be assessed globally for the first time, providing new insights into ecological contributions to the latitudinal diversity gradient.
PloS ONE (2017)
Reef Life Survey data are used to show complex but consistent responses to protection from fishing in well-enforced temperate New Zealand marine reserves.
Assessing National Biodiversity Trends for Rocky and Coral Reefs through the Integration of Citizen Science and Scientific Monitoring Programs
RLS provides a valuable template for improving national-scale marine biodiversity reporting, revealing where marine heatwaves, fishing and invasive species are having greatest effects on reef communities around Australia over the last decade.
New opportunities for conservation of handfishes (Family Brachionichthyidae) and other inconspicuous and threatened marine species through citizen science
Biological Conservation (2016)
The RLS survey program is a model for how skilled citizen scientists can enhance survey efforts of cryptic marine organisms, such as handfishes.
Journal of Experimental Marine Biology and Ecology (2016)
Ground-truthing dietary model predictions using stomach contents of Australian fish species.
The most sensitive coral reef fish species are identified along with their thresholds for human and climate stressors.
New Approaches to Marine Conservation Through the Scaling Up of Ecological Data
Annual Review of Marine Science (2016)
Advances in statistical analysis and the systematic collection compilation of global marine data aid in the progress of improving conservation outcomes.
Learning from ‘outliers’ – What are some of the common elements in marine management and local culture that are associated with places where reef fish biomass is much greater or much worse than we might expect?
More species = more fish biomass produced. Well-known from experiments, but RLS field data from around the world prove that biodiversity is critical to support fish production. Also, having more species even helps maintain fish production under ocean warming and increasing temperature extremes.
The distribution (geographical range) of fish and invertebrate species on reefs around the world informs us of where the majority of species are already living close to their upper temperature limits, or where most species could actually thrive with further warming.
PLoS One (2015)
A global comparison of fish feeding groups inside and outside MPAs shows that it is not just the predators (higher trophic levels) that have been overfished – but fishing has affected the larger members of all groups.
A standardised vocabulary for identifying benthic biota and substrata from underwater imagery: the CATAMI Classification Scheme.
PLoS ONE (2015)
The description of a new standard set of categories for scoring the cover of seaweeds and corals in photoquadrats (and video).
Ecology Letters (2015) Common characteristics of fish and invertebrate species that are extending further south with warming waters.
Marine Pollution Bulletin (2015)
Photoquadrat data show increased cover of fast-growing, opportunistic algae on reefs closer to Atlantic Salmon farms in Tasmania.
Intensive fish culture in open sea pens delivers large amounts of nutrients to coastal environments. Relative to particulate waste impacts, the ecological impacts of dissolved wastes are poorly known despite their potential to substantially affect nutrient-assimilating components of surrounding ecosystems. Broad-scale enrichment effects of salmonid farms on Tasmanian reef communities were assessed by comparing macroalgal cover at four fixed distances from active fish farm leases across 44 sites. Macroalgal assemblages differed significantly between sites immediately adjacent (100 m) to fish farms and reference sites at 5 km distance, while sites at 400 m and 1 km exhibited intermediate characteristics. Epiphyte cover varied consistently with fish farm impacts in both sheltered and exposed locations. The green algae Chaetomorpha spp. predominated near fish farms at swell-exposed sites, whereas filamentous green algae showed elevated densities near sheltered farms. Cover of canopy-forming perennial algae appeared unaffected by fish farm impacts.
Marine Pollution Bulletin (2015)
RLS surveys around major cities show trends in marine life related to major pollution sources, and numerous introduced species in Hobart.
Diversity and Distributions (2015)
A combination of RLS surveys and baited video undertaken by NSW marine parks staff show some responses of fish life to MPA protection evident in some younger MPAs
Diversity and Distributions 21:13-22 (2014)
New statistical approaches to help identify shifts in the range edges of species.
The redistribution of species with climate change is well documented.
Even so, the relative contribution of species detectability to the variation in
measured range shift rates among species is poorly understood. How can true
range shifts be discerned from sampling artefacts? Location Australia.
We simulate range shifts for species which differ in their abundance for comparison to patterns derived from empirical range shift data from two regional-scale (100s km) empirical studies. We demonstrate the use of spatial occupancy data in a distance-to-edge (DTE) model to assess changes in geographical range edges of fish species within a temperate reef fish community.
Simulations identified how sampling design can produce relatively larger error in range shift estimates in less abundant species, patterns that correspond with those observed in real data. Application of the DTE model allowed us to estimate the location of the true range edge with high accuracy in common species. In addition, upper confidence bounds for range edge estimates identified species with range edges that have likely shifted in location.
Simulation and modelling approaches used to quantify the level of confidence that can be placed in observed range shifts are particularly valuable for studies of marine species, where observations are typically few and patchy. Given the observed variability in range shift estimates, the inclusion of confidence bounds on estimates of geographical range edges will advance our capacity to disentangle true distributional change from artefacts of sampling design.
Climate warming, extreme value statistics, range edge estimation, sampling methodology.
Scientific Data 1: 140007 (2014)
Describes the Method 1 fish data in the RLS database, including collection methods and utility.
Nature 506: 216-220 (2014)
Identifies the design and management factors common among the most effective MPAs in the world.
Biological Conservation 173: 144-154 (2014)
Provides guidance on statistical methods for analyzing large scale datasets, including the RLS data
Nature Climate Change 4: 62-67 (2014)
Demonstrates that more in-tact fish communities in an effective MPA can help resist colonization by new warmer water species.
Nature 501: 539-542 (2013)
Adds an additional layer to understanding of the world’s fish diversity, showing patterns in abundance and characteristics of species that differ from patterns in species richness.
Global human footprint on the linkage between biodiversity and ecosystem functioning in reef fishes.
PLoS Biology 9: e1000606 (2011)
Explores the relationships between the number of species and the total biomass of reef fishes.
Research challenges to improve the management and conservation of subtropical reefs to tackle climate change threats.
Ecological Management and Restoration 12:e7 -e10 (2011)
A summary from a workshop of scientists and managers who work with reef communities in dynamic subtropical zones
Exploited reefs protected from fishing transform over decades into conservation features otherwise absent from seascapes
Ecological Applications 19: 1967-1974 (2009)
Fish biomass recovery in MPAs of different ages demonstrates the long time-frames needed for fish communities to return to a more natural state.
Ecological effects of marine protected areas on rocky reef communities: a continental-scale analysis
Marine Ecology Press Series 388: 51-62 (2009)
The first analysis of RLS data, including comparison of data quality from trainees vs scientists.