Corals

Supplementary Report to the Final Report of the Coral Reef Expert Group: S7. Coral reef models as assessment and reporting tools for the Reef 2050 Integrated Monitoring and Reporting Program – a review

Bozec YM, Mumby PJ. Supplementary Report to the Final Report of the Coral Reef Expert Group: S7. Coral reef models as assessment and reporting tools for the Reef 2050 Integrated Monitoring and Reporting Program – a review. Townsville: Great Barrier Reef Marine Park Authority; 2019.
Freely available?: 
Yes
Summary available?: 
No
Type: Report

The objective of this report is to review the existing models of temporal/spatial dynamics of coral communities available for the Great Barrier Reef (the Reef), with the specific aim at evaluating their strengths and weaknesses for the assessment and reporting of coral reef health within the Reef 2050 Integrated Monitoring and Reporting Program (RIMReP). Focusing on peer-reviewed articles available by 28 February 2018, we found that a variety of modeling approaches exists yet with different scope, level of complexity, and ability to represent the various processes driving the dynamics of coral populations. Tools available to model Reef coral population dynamics also vary in their capacity to capture the spatial heterogeneity of coral populations and their environment, the variability of disturbance impacts and the uncertainty around current reef state and possible future trajectory. The various characteristics and properties exhibited by coral reef models means they have different capacities to complement reef monitoring and assessment on the Reef. This review provides guidance for integrating a modeling component to RIMReP by identifying the modeling approaches that offer the strongest support to reef monitoring and management.

The report is organised as follows: In section 1, we list the potential benefits of ecological models for monitoring programs and explain how models can complement monitoring data and support the assessment of reef status and trends across the Reef. Section 2 provides an overview of the general characteristics and properties of ecological models, with the aim of facilitating the technical comparison of available coral reef models. In section 3, we summarise what we think are the key processes that influence the dynamics of coral populations. This provides a mechanistic framework allowing a comparison of models based on their ecological realism, i.e. their ability to reproduce changes in coral populations from the compounded action of individual demographic mechanisms. Section 4 provides an overview of the candidate coral models for the Reef, with their summary characteristics (model type, state variables, time steps), the ecological processes embedded, their parametrisation and model’s ability to capture the spatial dynamics of corals in a heterogeneous environment. For each model we highlight their strengths and weaknesses in complementing monitoring data to inform about status and trends across the Reef. Finally, we synthesise in section 5 the best candidate models, highlight their ability to inform management priorities for the Reef and make a number of recommendations for a successful integration into RIMReP.

Monitoring coral reefs within the Reef 2050 Integrated Monitoring and Reporting Program: final report of the coral reef expert group

Schaffelke B, Anthony K, Babcock R, Bridge T, Carlos E, Diaz-Pulido G, Gonzalez-Rivero M, Gooch M, Hoey A, Horne D, et al. Monitoring coral reefs within the Reef 2050 Integrated Monitoring and Reporting Program: final report of the coral reef expert group. Townsville: Great Barrier Reef Marine Park Authority; 2020. Available from: http://hdl.handle.net/11017/3562
Freely available?: 
Yes
Summary available?: 
No
Type: Report

The Coral Reef Expert Group (CREG) was one of eight expert groups, which all followed a prescribed process to recommend a design for their thematic component.

The tasks of the expert groups included:

  • Synopsis of the theme, to include discussion on current state, primary drivers, pressures and responses using DPSIR framework.
  • Review of all current monitoring and modelling activities relevant to the expert group theme.
  • Identify candidate indicators that can be monitored and would provide information about trend, status or forecasting of value or the system.
  • Evaluation of the adequacy and confidence of current monitoring and modelling of candidate indicators, determined by their ability to meet the objectives of the RIMReP and management needs provided by the Authority.
  • Identification and discussion of gaps and opportunities in current monitoring and modelling of such indicators.
  • Evaluation of new monitoring technologies for their potential to increase efficiency or statistical power and their compatibility with long-term datasets.
  • Recommendations for monitoring design including consideration of primary indicators, continuity of data sets, how the design addresses management needs, modification to existing programs, costing and transition strategies.

Cold-Water Corals and Other Vulnerable Biological Structures on a North Pacific Seamount After Half a Century of Fishing

Preez CDu, Swan KD, Curtis JMR. Cold-Water Corals and Other Vulnerable Biological Structures on a North Pacific Seamount After Half a Century of Fishing. Frontiers in Marine Science [Internet]. 2020 ;7. Available from: https://www.frontiersin.org/article/10.3389/fmars.2020.00017/full
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Addressing growing threats of overexploitation to the world’s oceans is especially challenging in the High Seas, where limited data and international jurisdiction make it difficult to determine where and when conservation measures are necessary. Of particular concern are vulnerable marine ecosystems (VMEs)—special habitats on the seafloor that are highly sensitive to disturbance and slow to recover. To ensure the long-term conservation and sustainable use of marine resources, regional fisheries management organizations are committed to identifying the locations of VMEs and responding to prevent significant adverse impacts (SAIs). For over 50 years, Cobb Seamount—a shallow underwater volcanic mountain in the Northeast Pacific Ocean—has been commercially fished by multiple nations using various types of gear. Here we have assimilated data from fisheries records and a recent visual survey on the seamount. Our findings show a variety of habitat-forming emergent biological structures widely distributed on Cobb Seamount and generally depth-stratified into high-density assemblages (≥1 m–2). Our spatial analyses show that fishing has also been widely distributed, overlapping the habitat of the biological structures. We found fewer cold-water corals, sponges, and other biological structures in areas with higher recent fishing effort and documented evidence of fishing impacts, such as extensive mats of coral rubble and a high abundance of derelict fishing gear entangled with dead or damaged organisms. Based on the average density of “lost” gear (2,785 ± 1,003 km–2), we can confidently estimate that hundreds of thousands of items of derelict fishing gear are currently entangled with the seafloor of Cobb Seamount and that these pose an ongoing threat to biological structures, the biogenic habitats they create, and the species they support. Such impacts can persist for decades or centuries to come. This study contributes and discusses new information on the condition and distribution of biological structures, VME indicator taxa, physically complex biogenic ecosystems, and human impacts on Cobb Seamount. These data will be necessary to identify the location(s) of potential VMEs and SAIs on this heavily fished seamount in the High Seas.

Oceanographic Drivers of Deep-Sea Coral Species Distribution and Community Assembly on Seamounts, Islands, Atolls, and Reefs Within the Phoenix Islands Protected Area

Auscavitch SR, Deere MC, Keller AG, Rotjan RD, Shank TM, Cordes EE. Oceanographic Drivers of Deep-Sea Coral Species Distribution and Community Assembly on Seamounts, Islands, Atolls, and Reefs Within the Phoenix Islands Protected Area. Frontiers in Marine Science [Internet]. 2020 ;7. Available from: https://www.frontiersin.org/article/10.3389/fmars.2020.00042/full
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

The Phoenix Islands Protected Area, in the central Pacific waters of the Republic of Kiribati, is a model for large marine protected area (MPA) development and maintenance, but baseline records of the protected biodiversity in its largest environment, the deep sea (>200 m), have not yet been determined. In general, the equatorial central Pacific lacks biogeographic perspective on deep-sea benthic communities compared to more well-studied regions of the North and South Pacific Ocean. In 2017, explorations by the NOAA ship Okeanos Explorer and R/V Falkor were among the first to document the diversity and distribution of deep-water benthic megafauna on numerous seamounts, islands, shallow coral reef banks, and atolls in the region. Here, we present baseline deep-sea coral species distribution and community assembly patterns within the Scleractinia, Octocorallia, Antipatharia, and Zoantharia with respect to different seafloor features and abiotic environmental variables across bathyal depths (200–2500 m). Remotely operated vehicle (ROV) transects were performed on 17 features throughout the Phoenix Islands and Tokelau Ridge Seamounts resulting in the observation of 12,828 deep-water corals and 167 identifiable morphospecies. Anthozoan assemblages were largely octocoral-dominated consisting of 78% of all observations with seamounts having a greater number of observed morphospecies compared to other feature types. Overlying water masses were observed to have significant effects on community assembly across bathyal depths. Revised species inventories further suggest that the protected area it is an area of biogeographic overlap for Pacific deep-water corals, containing species observed across bathyal provinces in the North Pacific, Southwest Pacific, and Western Pacific. These results underscore significant geographic and environmental complexity associated with deep-sea coral communities that remain in under-characterized in the equatorial central Pacific, but also highlight the additional efforts that need to be brought forth to effectively establish baseline ecological metrics in data deficient bathyal provinces.

Review of the State Party Report on the State of Conservation of the Great Barrier Reef World Heritage Area (Australia)

Tarte D, Hughes T. Review of the State Party Report on the State of Conservation of the Great Barrier Reef World Heritage Area (Australia). Australian Marine Conservation Society; 2020. Available from: https://independent.academia.edu/DiTarte
Freely available?: 
Yes
Summary available?: 
No
Type: Report

In response to the 2015 and 2017 decisions of the World Heritage Committee, the Australian government submitted to the World Heritage Centre in December 2019 the State Party Report on the state of conservation of the Great Barrier Reef (GBR) World Heritage Area (WHA). The 2017 decision of the World Heritage Committee (WHC) focussed on two areas in particular, namely:

4. .... accelerate efforts to ensure meeting the intermediate and long-term targets of the [Reef 2050 Long-Term Sustainability] plan ... in particular regarding water quality;

6. .... demonstrating the effective and sustained protection of the property’s Outstanding Universal Value and effective performance in meeting the targets established under the 2050 LTSP [Reef 2050 Long-Term Sustainability Plan], linked to the findings of the 2014 and 2019 Great Barrier Reef Outlook Reports.

This review also focusses on these two areas, as well as the implications of Australia’s current climate change polices and the existing funding arrangements for management of the GBR.

Relative to previous GBR State Party Reports (2013, 2014, 2015) the 2019 Report provides more detail on funding arrangements and progress to achieving management targets. Overall, it is a more informative document. However, it still overstates the efficacy of existing management arrangements and understates the critical importance of effectively and immediately addressing the causes of climate change. We are concerned particularly by the present Australian government’s inadequate national climate change and energy policies and programs, and the implications these have for the future of the Great Barrier Reef.

Megacity development and the demise of coastal coral communities: Evidence from coral skeleton δ15N records in the Pearl River estuary

Duprey NN, Wang TX, Kim T, Cybulski JD, Vonhof HB, Crutzen PJ, Haug GH, Sigman DM, Martínez‐García A, Baker DM. Megacity development and the demise of coastal coral communities: Evidence from coral skeleton δ15N records in the Pearl River estuary. Global Change Biology [Internet]. 2019 . Available from: https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.14923
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Historical coral skeleton (CS) δ18O and δ15N records were produced from samples recovered from sedimentary deposits, held in natural history museum collections, and cored into modern coral heads. These records were used to assess the influence of global warming and regional eutrophication, respectively, on the decline of coastal coral communities following the development of the Pearl River Delta (PRD) megacity, China. We find that, until 2007, ocean warming was not a major threat to coral communities in the Pearl River estuary; instead, nitrogen (N) inputs dominated impacts. The high but stable CS‐δ15N values (9‰–12‰ vs. air) observed from the mid‐Holocene until 1980 indicate that soil and stream denitrification reduced and modulated the hydrologic inputs of N, blunting the rise in coastal N sources during the early phase of the Pearl River estuary urbanization. However, an unprecedented CS‐δ15N peak was observed from 1987 to 1993 (>13‰ vs. air), concomitant to an increase of NH4+ concentration, consistent with the rapid Pearl River estuary urbanization as the main cause for this eutrophication event. We suggest that widespread discharge of domestic sewage entered directly into the estuary, preventing removal by natural denitrification hotspots. We argue that this event caused the dramatic decline of the Pearl River estuary coral communities reported from 1980 to 2000. Subsequently, the coral record shows that the implementation of improved wastewater management policies succeeded in bringing down both CS‐δ15N and NH4+ concentrations in the early 2000s. This study points to the potential importance of eutrophication over ocean warming in coral decline along urbanized coastlines and in particular in the vicinity of megacities.

New insights into the ecology and conservation of bryozoans: from global diversity patterns to the responses to anthropogenic stressors in the Mediterranean Sea

Escolà MPagès. New insights into the ecology and conservation of bryozoans: from global diversity patterns to the responses to anthropogenic stressors in the Mediterranean Sea. University of Barcelona; 2018.
Freely available?: 
Yes
Summary available?: 
No
Type: Thesis

Marine ecosystems are directly threatened by multiple and interactive human stressors at global and local scales. Hence, it is vital to study biodiversity and ecological patterns through a multi-disciplinary approach, from understanding global diversity patterns to evaluating the ecological responses of species to different impacts in order to protect marine ecosystems. Until this moment most of related ecological studies have focused on charismatic and popular groups, such as gorgonians, corals, macroalgae or seagrasses. In this thesis, we focused on bryozoans, an abundant group of sessile marine invertebrates distributed worldwide, but generally understudied. Moreover, large bryozoans are considered habitat-forming species that can create bioconstructions enhancing the associated biodiversity and providing different ecological benefits. Bearing this in mind, the main aim of this thesis was to provide different approaches to understand discovery and macroecological patterns at global scales, and the response of species to different stressors at local scales, combining the use of open databases, the in situ monitoring of natural populations, experiments in aquaria and the development of restoration techniques. Furthermore, the present thesis aims to contribute to provide a general framework to identify and protect vulnerable populations in the context of increasing human threats.

In the first chapter, the discovery patterns of fossil and extant bryozoans revealed the highest number of fossil species described, highlighting that the current biodiversity represents only a small proportion of Earth’s past biodiversity. Beyond these differences, both groups showed an increase in the taxonomic effort during the past century, reflecting the increase in the interest in the exploration of the marine environment, and the improvement of technological developments. Despite this progress, future projections of discovery patterns of both groups showed a large proportion of species remaining to be discovered by the end of this century, which corroborate the need to increase the effort to name and quantify marine biodiversity before hundreds of species become extinct due to human impacts.

In chapter 2, a comparative approach between marine sessile and bryozoan biodiversity patterns reported that the most of sessile groups presented higher diversity in the Southern ocean, displaying a non-unimodal latitudinal pattern with a dip in the number of species at the equator, contrary to the most traditionally accepted pattern in diversity studies. Moreover, this region will represent the less affected by global warming at the final of this century, suggesting that the high species richness recorded in this region may be explained by it has suffered lower temperature stress over evolutionary time. Related to biases in sampling effort, our analyses showed that the most sampled region for both marine sessile species and bryozoans was North Temperate Atlantic. To identify and quantify environmental drivers for both groups, we tested the effect of using the popular method of rarefaction to correct sampling effort biases vs the incorporation of a frequency index of sampling effort as co-variate in quantitative models. Despite we obtained the same best predictors for both approches (depth, nitrate, and SST), the models using the correction of sampling biases through frequency index showed better fitting, encouraging to incorporate this methodology in future studies.

Focusing on the Mediterranean Sea, in Chapter 3 we studied the responses of bryozoans to different stressors. First, we showed that two abundant and common bryozoans, Pentapora fascialis and Myriapora truncata, displayed different tolerances to warming. Through the combination of in situ monitoring and experiments in aquaria, we revealed that mass mortality event recorded of Pentapora fascialis populations during summer 2015 may be explained by its lower thermal tolerance ranks. Moreover, in Chapter 4 we take the advantage of the in situ monitoring of Pentapora fascialis natural populations increasing the spatial and temporal effort, revealing that the bryozoan Pentapora fascialis is characterized by fast population dynamics, with high recruitment and growth rates, and a high capacity of recovery. Accordingly, we observed an increase in the density of its populations in the Marine Reserve of Medes Island since the 1990s. However, we evidenced that in this Marine Protected Area, diving can impact on the density, recruitment, survival, and the size of the colonies, registering lower values in frequented localities. Our results highlight that although Marine Protected Areas have been recognized as effective management and conservation tools to protect coastal ecosystems, the over frequentation of divers compromises the future viability of populations, highlighting the need to explore other management strategies.

In this context, for the first time in Chapter 5, different restoration techniques for bryozoans were developed and tested, focusing on the recruitment enhancement through the installation of recruitment surfaces and the transplantation of adult colonies of Pentapora fascialis. Plastic grids represented the best substrate in terms of facilitating the recruitment of our model species. The most successful technique to transplant adult colonies was to fix the colonies to the substrate with a nylon thread attached to the colony ex situ. The successful results and the affordable and economic cost of tested techniques aim to encourage the managers of Marine Protected Areas to apply similar methodologies to restore and conserve bryozoan temperate bioconstructions and the ecological services that they provide.

The results presented in this thesis show the importance to combine different approaches to understand the global and local ecological patterns of understudied but abundant groups, such as bryozoans. Our findings enlarge the current ecological knowledge of bryozoans at different scales, and highlight that more effort is needed to protect vulnerable populations. Accordingly, adaptive management formal plans and restoration actions are required to promote the conservation of marine communities in the context of increasing local and global stressors.

Building resilience in practice to support coral communities in the Western Indian Ocean

Hattam C, Evans L, Morrissey K, Hooper T, Young K, Khalid F, Bryant M, Thani A, Slade L, Perry C, et al. Building resilience in practice to support coral communities in the Western Indian Ocean. Environmental Science & Policy [Internet]. 2020 ;106:182 - 190. Available from: https://www.sciencedirect.com/science/article/pii/S1462901119308044
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Global environmental change and other site specific pressures (e.g. over fishing and pollution) are threating coral reefs and the livelihoods of dependent coastal communities. Multiple strategies are used to build the resilience of both coral reefs and reef dependent communities but the effectiveness of these strategies is largely unknown. Using the Western Indian Ocean (WIO) as a case study, this paper combines published literature and expert opinion elicited through a multi-stakeholder workshop to assess the intended and realised social and ecological implications of strategies commonly applied in the region. Findings suggest that all strategies can contribute to building social and ecological resilience, but this varies with context and the overall strategy objectives. The ability of strategies to be successful in the future is questioned. To support effective resilience policy development more nuanced lesson learning requires effective monitoring and evaluation as well as a disaggregated understanding of resilience in terms of gender, agency and the interaction between ecological and social resilience. Opportunities for further lesson sharing between experts in the region are needed.

Sexual production of corals for reef restoration in the Anthropocene

Randall CJ, Negri AP, Quigley KM, Foster T, Ricardo GF, Webster NS, Bay LK, Harrison PL, Babcock RC, Heyward AJ. Sexual production of corals for reef restoration in the Anthropocene. Marine Ecology Progress Series [Internet]. 2020 ;v635:203 - 232. Available from: https://www.int-res.com/abstracts/meps/v635/p203-232
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Coral-reef ecosystems are experiencing frequent and severe disturbance events that are reducing global coral abundance and potentially overwhelming the natural capacity for reefs to recover. While mitigation strategies for climate warming and other anthropogenic disturbances are implemented, coral restoration programmes are being established worldwide as an additional conservation measure to minimise coral loss and enhance coral recovery. Current restoration efforts predominantly rely on asexually produced coral fragments—a process with inherent practical constraints on the genetic diversity conserved and the spatial scale achieved. Because the resilience of coral communities has hitherto relied on regular renewal with natural recruits, the scaling-up of restoration programmes would benefit from greater use of sexually produced corals, which is an approach that is gaining momentum. Here we review the present state of knowledge of scleractinian coral sexual reproduction in the context of reef restoration, with a focus on broadcast-spawning corals. We identify key knowledge gaps and bottlenecks that currently constrain the sexual production of corals and consider the feasibility of using sexually produced corals for scaling-up restoration to the reef- and reef-system scales.

Monitoring of Coral Reefs Using Artificial Intelligence: A Feasible and Cost-Effective Approach

González-Rivero M, Beijbom O, Rodriguez-Ramirez A, Bryant DEP, Ganase A, Gonzalez-Marrero Y, Herrera-Reveles A, Kennedy EV, Kim CJS, Lopez-Marcano S, et al. Monitoring of Coral Reefs Using Artificial Intelligence: A Feasible and Cost-Effective Approach. Remote Sensing [Internet]. 2020 ;12(3):489. Available from: https://www.mdpi.com/2072-4292/12/3/489
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Ecosystem monitoring is central to effective management, where rapid reporting is essential to provide timely advice. While digital imagery has greatly improved the speed of underwater data collection for monitoring benthic communities, image analysis remains a bottleneck in reporting observations. In recent years, a rapid evolution of artificial intelligence in image recognition has been evident in its broad applications in modern society, offering new opportunities for increasing the capabilities of coral reef monitoring. Here, we evaluated the performance of Deep Learning Convolutional Neural Networks for automated image analysis, using a global coral reef monitoring dataset. The study demonstrates the advantages of automated image analysis for coral reef monitoring in terms of error and repeatability of benthic abundance estimations, as well as cost and benefit. We found unbiased and high agreement between expert and automated observations (97%). Repeated surveys and comparisons against existing monitoring programs also show that automated estimation of benthic composition is equally robust in detecting change and ensuring the continuity of existing monitoring data. Using this automated approach, data analysis and reporting can be accelerated by at least 200x and at a fraction of the cost (1%). Combining commonly used underwater imagery in monitoring with automated image annotation can dramatically improve how we measure and monitor coral reefs worldwide, particularly in terms of allocating limited resources, rapid reporting and data integration within and across management areas.

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