RESUMO
Living shorelines aim to enhance the resilience of coastlines to hazards while simultaneously delivering co-benefits such as carbon sequestration. Despite the potential ecological and socio-economic benefits of living shorelines over conventional engineered coastal protection structures, application is limited globally. Australia has a long and diverse coastline that provides prime opportunities for living shorelines using beaches and dunes, vegetation, and biogenic reefs, which may be either natural ('soft' approach) or with an engineered structural component ('hybrid' approach). Published scientific studies, however, have indicated limited use of living shorelines for coastal protection in Australia. In response, we combined a national survey and interviews of coastal practitioners and a grey and peer-reviewed literature search to (1) identify barriers to living shoreline implementation; and (2) create a database of living shoreline projects in Australia based on sources other than scientific literature. Projects included were those that had either a primary or secondary goal of protection of coastal assets from erosion and/or flooding. We identified 138 living shoreline projects in Australia through the means sampled starting in 1970; with the number of projects increasing through time particularly since 2000. Over half of the total projects (59 %) were considered to be successful according to their initial stated objective (i.e., reducing hazard risk) and 18 % of projects could not be assessed for their success based on the information available. Seventy percent of projects received formal or informal monitoring. Even in the absence of peer-reviewed support for living shoreline construction in Australia, we discovered local and regional increases in their use. This suggests that coastal practitioners are learning on-the-ground, however more generally it was stated that few examples of living shorelines are being made available, suggesting a barrier in information sharing among agencies at a broader scale. A database of living shoreline projects can increase knowledge among practitioners globally to develop best practice that informs technical guidelines for different approaches and helps focus attention on areas for further research.
Assuntos
Sequestro de Carbono , Inundações , AustráliaRESUMO
The worldwide decline of coral reefs has renewed interest in coral communities at the edge of environmental limits because they have the potential to serve as resilience hotspots and climate change refugia, and can provide insights into how coral reefs might function in future ocean conditions. These coral communities are often referred to as marginal or extreme but few definitions exist and usage of these terms has therefore been inconsistent. This creates significant challenges for categorising these often poorly studied communities and synthesising data across locations. Furthermore, this impedes our understanding of how coral communities can persist at the edge of their environmental limits and the lessons they provide for future coral reef survival. Here, we propose that marginal and extreme coral communities are related but distinct and provide a novel conceptual framework to redefine them. Specifically, we define coral reef extremeness solely based on environmental conditions (i.e., large deviations from optimal conditions in terms of mean and/or variance) and marginality solely based on ecological criteria (i.e., altered community composition and/or ecosystem functioning). This joint but independent assessment of environmental and ecological criteria is critical to avoid common pitfalls where coral communities existing outside the presumed optimal conditions for coral reef development are automatically considered inferior to coral reefs in more traditional settings. We further evaluate the differential potential of marginal and extreme coral communities to serve as natural laboratories, resilience hotspots and climate change refugia, and discuss strategies for their conservation and management as well as priorities for future research. Our new classification framework provides an important tool to improve our understanding of how corals can persist at the edge of their environmental limits and how we can leverage this knowledge to optimise strategies for coral reef conservation, restoration and management in a rapidly changing ocean.
Assuntos
Antozoários , Animais , Ecossistema , Recifes de Corais , Mudança Climática , Refúgio de Vida SelvagemRESUMO
Encrusting reef organisms such as crustose coralline algae (CCA), serpulid worms, bivalves, bryozoans, and foraminifera (collectively termed encrusters) provide essential ecosystem services and are a critical part of the reef framework. Globally, research into in situ growth and carbonate production of encrusters has focused on clear water fore-reef settings in the Pacific and Caribbean, with limited studies being conducted on marginal reef systems or within the Indian Ocean. Here we examined spatial and temporal variation in CCA coverage (%) and total encruster carbonate production rates (g cm-2 yr-1) across two inshore turbid island reefs of northern Western Australia. We recorded average carbonate production rates of 0.039 ± 0.002 g cm-2 yr-1, which are comparable to healthy reef sites globally. Our results show variation in lateral CCA cover over small spatial scales, with a strong seasonal signature, while constant average carbonate production rates were maintained. Additionally, we recorded in situ water temperatures above predicted coral bleaching threshold of 29 °C for four weeks and found annual patterns of sea surface temperature anomalies (SSTA) of 2 °C or more being a regular occurrence over the hotter months. Encrusters on these reefs are considered to have a vital contribution to the reef carbonate budgets, and if they maintain stable carbonate production through periods of SSTA, they may support net positive reef carbonate budgets.
Assuntos
Antozoários , Recifes de Corais , Animais , Carbonatos , Região do Caribe , Ecossistema , Oceano Índico , Temperatura , Austrália OcidentalRESUMO
Ocean warming and acidification threaten the future growth of coral reefs. This is because the calcifying coral reef taxa that construct the calcium carbonate frameworks and cement the reef together are highly sensitive to ocean warming and acidification. However, the global-scale effects of ocean warming and acidification on rates of coral reef net carbonate production remain poorly constrained despite a wealth of studies assessing their effects on the calcification of individual organisms. Here, we present global estimates of projected future changes in coral reef net carbonate production under ocean warming and acidification. We apply a meta-analysis of responses of coral reef taxa calcification and bioerosion rates to predicted changes in coral cover driven by climate change to estimate the net carbonate production rates of 183 reefs worldwide by 2050 and 2100. We forecast mean global reef net carbonate production under representative concentration pathways (RCP) 2.6, 4.5, and 8.5 will decline by 76, 149, and 156%, respectively, by 2100. While 63% of reefs are projected to continue to accrete by 2100 under RCP2.6, 94% will be eroding by 2050 under RCP8.5, and no reefs will continue to accrete at rates matching projected sea level rise under RCP4.5 or 8.5 by 2100. Projected reduced coral cover due to bleaching events predominately drives these declines rather than the direct physiological impacts of ocean warming and acidification on calcification or bioerosion. Presently degraded reefs were also more sensitive in our analysis. These findings highlight the low likelihood that the world's coral reefs will maintain their functional roles without near-term stabilization of atmospheric CO2 emissions.
Assuntos
Antozoários/fisiologia , Carbonato de Cálcio/metabolismo , Mudança Climática , Recifes de Corais , Animais , Antozoários/química , Carbonato de Cálcio/química , Humanos , Concentração de Íons de Hidrogênio , Oceanos e Mares , Água do Mar/químicaRESUMO
Understanding complex systems is essential to ensure their conservation and effective management. Models commonly support understanding of complex ecological systems and, by extension, their conservation. Modeling, however, is largely a social process constrained by individuals' mental models (i.e., a small-scale internal model of how a part of the world works based on knowledge, experience, values, beliefs, and assumptions) and system complexity. To account for both system complexity and the diversity of knowledge of complex systems, we devised a novel way to develop a shared qualitative complex system model. We disaggregated a system (carbonate coral reefs) into smaller subsystem modules that each represented a functioning unit, about which an individual is likely to have more comprehensive knowledge. This modular approach allowed us to elicit an individual mental model of a defined subsystem for which the individuals had a higher level of confidence in their knowledge of the relationships between variables. The challenge then was to bring these subsystem models together to form a complete, shared model of the entire system, which we attempted through 4 phases: develop the system framework and subsystem modules; develop the individual mental model elicitation methods; elicit the mental models; and identify and isolate differences for exploration and identify similarities to cocreate a shared qualitative model. The shared qualitative model provides opportunities to develop a quantitative model to understand and predict complex system change.
Desarrollo de Modelos Cualitativos Compartidos para Sistemas Complejos Resumen El entendimiento de los sistemas complejos es esencial para asegurar su conservación y manejo efectivo. Es común que los modelos respalden el entendimiento de los sistemas ecológicos complejos y, por extensión, su conservación. Sin embargo, el modelado es principalmente un proceso social restringido por los modelos mentales de los individuos (es decir, un modelo interno a pequeña escala de cómo funciona una parte del mundo con base en el conocimiento, las experiencias, valores, creencias y suposiciones) y la complejidad del sistema. Para considerar tanto la complejidad del sistema como la diversidad de conocimiento sobre los sistemas complejos, diseñamos un método novedoso para desarrollar un modelo cualitativo de sistemas complejos. Desglosamos un sistema (arrecifes de coral de carbonato) en módulos más pequeños o subsistemas y cada uno representó una unidad funcional, sobre la cual es más probable que un individuo tenga mayor conocimiento integral. Este enfoque modular nos permitió obtener un modelo mental individual de un subsistema definido para el cual los individuos tuvieron un nivel más alto de confianza en su conocimiento sobre las relaciones entre las variables. Entonces, el reto fue juntar estos modelos de subsistemas para formar un modelo compartido completo del sistema entero, lo cual intentamos a lo largo de cuatro fases: desarrollar el marco de trabajo para el sistema y los módulos de los subsistemas; desarrollar los métodos de obtención para los modelos mentales individuales; obtener los modelos mentales; e identificar y aislar las diferencias para la exploración, así como identificar similitudes para crear conjuntamente un modelo cualitativo compartido. El modelo cualitativo compartido proporciona oportunidades para desarrollar un modelo cuantitativo que permita entender y predecir el cambio en los sistemas complejos.
Assuntos
Conservação dos Recursos Naturais , Recifes de Corais , Ecossistema , HumanosRESUMO
Extreme climate events, such as the El Niños in 1997/1998 and 2015/16, have led to considerable forest loss in the Southeast Asian region following unprecedented drought and wildfires. In Borneo, the effects of extreme climate events have been exacerbated by rapid urbanization, accelerated deforestation and soil erosion since the 1980s. However, studies quantifying the impact of interannual and long-term (>3 decades) climatic and anthropogenic change affecting Borneo's coastal and coral reef environments are lacking. Here, we used coral cores collected in Miri-Sibuti Coral Reefs National Park, Sarawak (Malaysia) to reconstruct the spatio-temporal dynamics of sea surface temperature and oxygen isotopic composition of seawater from 1982 to 2016, based on paired oxygen isotope and Sr/Ca measurements. The results revealed rising sea surface temperatures of 0.26 ± 0.04 °C per decade since 1982. Reconstructed δ18Osw displayed positive excursion during major El Niño events of 1983, 1997/98 and 2015/16, indicating drought conditions with less river runoff, rainfall and higher ocean salinities. La Niñas were generally associated with lower δ18Osw. We observed a long-term shift from more saline conditions between 1982 and 1995 towards less saline conditions after 1995, which are in agreement with the regional freshening trend, punctuated by saline excursion during El Niños. The decadal shifts were found to be driven by the Pacific Decadal Oscillation (PDO). This study provides the first long-term data on El Niño Southern Oscillation (ENSO)-driven synchrony of climate impacts on both terrestrial and marine ecosystems in northern Borneo. Our results suggest that coral records from northern Borneo are invaluable archives to detect regional ENSO and PDO impacts, and their interaction with the Asian-Australian monsoon, on the hydrological balance in the southern South China Sea beyond the past three decades.
Assuntos
Antozoários , Recifes de Corais , El Niño Oscilação Sul , Modelos Biológicos , Animais , BornéuRESUMO
For reefs in South East Asia the synergistic effects of rapid land development, insufficient environmental policies and a lack of enforcement has led to poor water quality and compromised coral health from increased sediment and pollution. Those inshore turbid coral reefs, subject to significant sediment inputs, may also inherit some resilience to the effects of thermal stress and coral bleaching. We studied the inshore turbid reefs near Miri, in northwest Borneo through a comprehensive assessment of coral cover and health in addition to quantifying sediment-related parameters. Although Miri's Reefs had comparatively low coral species diversity, dominated by massive and encrusting forms of Diploastrea, Porites, Montipora, Favites, Dipsastrea and Pachyseris, they were characterized by a healthy cover ranging from 22 to 39%. We found a strong inshore to offshore gradient in hard coral cover, diversity and community composition as a direct result of spatial differences in sediment at distances <10 km. As well as distance to shore, we included other environmental variables like reef depth and sediment trap accumulation and particle size that explained 62.5% of variation in benthic composition among sites. Miri's reefs showed little evidence of coral disease and relatively low prevalence of compromised health signs including bleaching (6.7%), bioerosion (6.6%), pigmentation response (2.2%), scars (1.1%) and excessive mucus production (0.5%). Tagged colonies of Diploastrea and Pachyseris suffering partial bleaching in 2016 had fully (90-100%) recovered the following year. There were, however, seasonal differences in bioerosion rates, which increased five-fold after the 2017 wet season. Differences in measures of coral physiology, like that of symbiont density and chlorophyll a for Montipora, Pachyseris and Acropora, were not detected among sites. We conclude that Miri's reefs may be in a temporally stable state given minimal recently dead coral and a limited decline in coral cover over the last two decades. This study provides further evidence that turbid coral reefs exposed to seasonally elevated sediment loads can exhibit relatively high coral cover and be resilient to disease and elevated sea surface temperatures.
RESUMO
Given predicted increases in urbanization in tropical and subtropical regions, understanding the processes shaping urban coral reefs may be essential for anticipating future conservation challenges. We used a case study approach to identify unifying patterns of urban coral reefs and clarify the effects of urbanization on hard coral assemblages. Data were compiled from 11 cities throughout East and Southeast Asia, with particular focus on Singapore, Jakarta, Hong Kong, and Naha (Okinawa). Our review highlights several key characteristics of urban coral reefs, including "reef compression" (a decline in bathymetric range with increasing turbidity and decreasing water clarity over time and relative to shore), dominance by domed coral growth forms and low reef complexity, variable city-specific inshore-offshore gradients, early declines in coral cover with recent fluctuating periods of acute impacts and rapid recovery, and colonization of urban infrastructure by hard corals. We present hypotheses for urban reef community dynamics and discuss potential of ecological engineering for corals in urban areas.
Assuntos
Conservação dos Recursos Hídricos , Recifes de Corais , Animais , Antozoários , Sudeste Asiático , Cidades , Conservação dos Recursos Hídricos/métodos , Conservação dos Recursos Hídricos/tendências , Ecossistema , Hong Kong , Indonésia , Japão , Singapura , Poluição da ÁguaRESUMO
Near-shore marine environments are increasingly subjected to reduced water quality, and their ability to withstand it is critical to their persistence. The potential role marine reserves may play in mitigating the effects of reduced water quality has received little attention. We investigated the spatial and temporal variability in live coral and macro-algal cover and water quality during moderate and major flooding events of the Fitzroy River within the Keppel Bay region of the Great Barrier Reef Marine Park from 2007 to 2013. We used 7 years of remote sensing data on water quality and data from long-term monitoring of coral reefs to quantify exposure of coral reefs to flood plumes. We used a distance linear model to partition the contribution of abiotic and biotic factors, including zoning, as drivers of the observed changes in coral and macro-algae cover. Moderate flood plumes from 2007 to 2009 did not affect coral cover on reefs in the Keppel Islands, suggesting the reef has intrinsic resistance against short-term exposure to reduced water quality. However, from 2009 to 2013, live coral cover declined by â¼ 50% following several weeks of exposure to turbid, low salinity water from major flood plume events in 2011 and subsequent moderate events in 2012 and 2013. Although the flooding events in 2012 and 2013 were smaller than the flooding events between 2007 to 2009, the ability of the reefs to withstand these moderate floods was lost, as evidenced by a â¼ 20% decline in coral cover between 2011 to 2013. Although zoning (no-take reserve or fished) was identified a significant driver of coral cover, we recorded consistently lower coral cover on reserve reefs than on fished reefs throughout the study period and significantly lower cover in 2011. Our findings suggest that even reefs with an inherent resistance to reduced water quality are not able to withstand repeated disturbance events. The limitations of reserves in mitigating the effects of reduced water quality on near-shore coral reefs underscores the importance of integrated management approaches that combine effective land-based management with networks of no-take reserves.
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Conservação dos Recursos Naturais , Recifes de Corais , Qualidade da Água , Distribuição Animal , Animais , Antozoários/fisiologia , Inundações , Queensland , Alga Marinha/fisiologiaRESUMO
Environmental drivers of coral condition (maximum quantum yield, symbiont density, chlorophyll a content and coral skeletal growth rates) were assessed in the equatorial inshore coastal waters of Singapore, where the amplitude of seasonal variation is low, but anthropogenic influence is relatively high. Water quality variables (sediments, nutrients, trace metals, temperature, light) explained between 52 and 83% of the variation in coral condition, with sediments and light availability as key drivers of foliose corals (Merulina ampliata, Pachyseris speciosa), and temperature exerting a greater influence on a branching coral (Pocillopora damicornis). Seasonal reductions in water quality led to high chlorophyll a concentrations and maximum quantum yields in corals, but low growth rates. These marginal coral communities are potentially vulnerable to climate change, hence, we propose water quality thresholds for coral growth with the aim of mitigating both local and global environmental impacts.
Assuntos
Antozoários/fisiologia , Estações do Ano , Qualidade da Água , Animais , Antozoários/crescimento & desenvolvimento , Clorofila/análise , Clorofila A , Mudança Climática , Monitoramento Ambiental , Sedimentos Geológicos/química , Análise de Componente Principal , Chuva , Água do Mar/química , Singapura , TemperaturaRESUMO
Sediment loads have long been known to be deleterious to corals, but the effects of turbidity and settling particles have not previously been partitioned. This study provides a novel approach using inert silicon carbide powder to partition and quantify the mechanical effects of sediment settling versus reduced light under a chronically high sedimentary regime on two turbid water corals commonly found in Singapore (Galaxea fascicularis and Goniopora somaliensis). Coral fragments were evenly distributed among three treatments: an open control (30% ambient PAR), a shaded control (15% ambient PAR) and sediment treatment (15% ambient PAR; 26.4 mg cm(-2) day(-1)). The rate of photosynthesis and respiration, and the dark-adapted quantum yield were measured once a week for four weeks. By week four, the photosynthesis to respiration ratio (P/R ratio) and the photosynthetic yield (Fv/Fm) had fallen by 14% and 3-17% respectively in the shaded control, contrasting with corals exposed to sediments whose P/R ratio and yield had declined by 21% and 18-34% respectively. The differences in rates between the shaded control and the sediment treatment were attributed to the mechanical effects of sediment deposition. The physiological response to sediment stress differed between species with G. fascicularis experiencing a greater decline in the net photosynthetic yield (13%) than G. somaliensis (9.5%), but a smaller increase in the respiration rates (G. fascicularis = 9.9%, G. somaliensisâ = 14.2%). These different physiological responses were attributed, in part, to coral morphology and highlighted key physiological processes that drive species distribution along high to low turbidity and depositional gradients.
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Antozoários/efeitos dos fármacos , Antozoários/efeitos da radiação , Metabolismo Energético/efeitos dos fármacos , Metabolismo Energético/efeitos da radiação , Sedimentos Geológicos/química , Luz , Fenômenos Ópticos , Animais , Antozoários/metabolismo , Antozoários/fisiologia , Respiração Celular/efeitos dos fármacos , Respiração Celular/efeitos da radiação , Fenômenos Mecânicos , Fotossíntese/efeitos dos fármacos , Fotossíntese/efeitos da radiaçãoRESUMO
Due to a recent and dramatic rise in suicide and self-harm rates, mental health services have received a high level of attention in the politics of Northern Ireland, resulting in the implementation of numerous policies and the publication of many public reviews on the subject. Critically, these policies have also emphasized and required the participation of mental health service users in decision making about service design, implementation, and monitoring. This paper analyzes the experience of a group of mental health service users in north and west Belfast, the Public Initiative for the Prevention of Suicide-Greater Shankill Bereaved Families Rights Group supported by the Particpation and the Practice of Rights Project, as they campaigned for policy change using a human rights-based approach. It considers, first, the group's use of a participatory, "bottom-up" approach to set human rights indicators and benchmarks defined by group members themselves as an example of meaningful participation from an affected group. The paper then looks specifically at one of the group's issues--follow-up care--and reveals how the group was able to bring about policy change on this issue across Northern Ireland. Finally, it discusses how the group's experience in this campaign has revealed problems with the way that the government currently engages with mental health service users in Northern Ireland. The article closes by identifying key next steps to be taken as the focus of the campaign shifts to ensuring that active, free, and meaningful participation takes place in accordance with international human rights standards.