Coral Reef Soundscapes: Spatiotemporal Variability and Links to Species Assemblages PDF Download

Author: Maxwell Bernard Kaplan
Publisher:
ISBN:
Category : Corals
Languages : en
Pages : 143

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Book Description
Coral reefs are biodiverse ecosystems that are at risk of degradation as a result of environmental changes. Reefs are constantly in a state of flux: the resident species assemblages vary considerably in space and time. However, the drivers of this variability are poorly understood. Tracking these changes and studying how coral reefs respond to natural and anthropogenic disturbance can be challenging and costly, particularly for reefs that are located in remote areas. Because many reef animals produce and use sound, recording the ambient soundscape of a reef might be one way to efficiently study these habitats from afar. In this thesis, I develop and apply a suite of acoustics-based tools to characterize the biological and anthropogenic acoustic activity that largely comprises marine soundscapes. First, I investigate links between reef fauna and reef-specific acoustic signatures on coral reefs located in the U.S. Virgin Islands. Second, I compare those findings to a more expansive study that I conducted in Maui, Hawaii, in which the drivers of bioacoustic differences among reefs are explored. Third, I investigate the distances over which sounds of biological origin may travel away from the reef and consider the range within which these acoustic cues might be usable by pelagic larvae in search of a suitable adult habitat. Fourth, I assess the extent to which the presence of vessel noise in shallow-water habitats changes the ambient soundscape. Finally, I present the results of a modeling exercise that questions how ocean noise levels might change over the next two decades as a result of major projected increases in the number and size of and distance traveled by commercial ships. The acoustics-based tools presented here help provide insight into ecosystem function and the extent of human activity in a given habitat. Additionally, these tools can be used to inform an effective regulatory regime to improve coral reef ecosystem management.

Author: Erica Staaterman
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Most coral reef fish adults have limited home ranges, but their pelagic larvae have the potential to disperse over great distances. At the end of the pelagic phase, these larvae must seek appropriate settlement habitat. Which environmental signals do they use to find the reef? It has been suggested that fish larvae utilize a combination of visual, olfactory, and acoustic cues at different ontogenetic stages and different distances from the reef. At least ten experiments in the last decade have tested the response of reef fish larvae to sounds of a coral reef, resulting in more than 650 citations. This dissertation focuses on the potential role of acoustic cues in the orientation behavior of larval reef fish from the open ocean. First, a biophysical model was used to examine the consequences of orientation behavior if larvae could detect acoustic signals from 1-10 km from the reef. When larvae oriented early during ontogeny and from larger distances, they greatly increased their settlement success and settled closer to home. These findings suggest that early orientation is critical to the survival of fish larvae, which must be active agents of their own dispersal. Second, a time-series of coral reef soundscapes was conducted for two nearby coral reefs in the Northern Florida Keys. The reef soundscapes were highly variable over daily, lunar, and seasonal time-scales, and the highest amplitudes coincided with new moons of the wet season - the time when the larvae of most coral reef fish species settle. Interestingly, the wind-based contribution to the soundscape also had a lunar period. Third, an acoustic playback experiment was conducted at Dean's Blue Hole in the Bahamas, a relatively "quiet" environment. Larvae from Apogonidae (cardinalfish) and Acanthuridae (surgeonfish) families were exposed to reef sounds recorded in the Bahamas and in Florida and played back at ambient levels. The acanthurid species demonstrated no response to the playbacks, but the apogonids exhibited a disruption of their orientation behavior. This finding suggests that apogonids were able to detect the playbacks, but had no directional response, as was anticipated based on previous studies where sounds were broadcast at higher amplitudes. Finally, an acoustic propagation experiment was conducted in the Upper Florida Keys. Both acoustic pressure and particle acceleration diminished gradually with distance from the reef, but the amplitude of the signal, particularly for particle acceleration, was lower than the detection thresholds of most fish larvae. Furthermore, the particle acceleration field (measured 1-1000 m from the reef) was not highly directional, which may restrict the use of acoustic signals to animals that can detect acoustic pressure. These findings suggest that most fish larvae in the pelagic zone near Florida reefs would have a difficult time locating the reef using acoustic cues alone. However, this may not be the case for species with particularly sensitive hearing (e.g., those that can detect acoustic pressure), and for reefs with higher-amplitude soundscapes. The results of this study challenge research from the past decades that demonstrated a clear attraction of larval fishes to sounds played-back at high amplitudes. Further work is needed, specifically hearing thresholds in other fish larvae, and particle acceleration measurements over longer time periods and near additional coral reefs, to determine whether the trends found in the Florida Keys are consistent with other parts of the world.

Author: Emma Collins
Publisher:
ISBN:
Category :
Languages : en
Pages : 60

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Author: Jonathan Turnbull Phinney
Publisher: American Geophysical Union
ISBN: 0875903592
Category : Science
Languages : en
Pages : 251

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Published by the American Geophysical Union as part of the Coastal and Estuarine Studies, Volume 61. The effects of increased atmospheric carbon dioxide and related climate change on shallow coral reefs are gaining considerable attention for scientific and economic reasons worldwide. Although increased scientific research has improved our understanding of the response of coral reefs to climate change, we still lack key information that can help guide reef management. Research and monitoring of coral reef ecosystems over the past few decades have documented two major threats related to increasing concentrations of atmospheric CO2: (1) increased sea surface temperatures and (2) increased seawater acidity (lower pH). Higher atmospheric CO2 levels have resulted in rising sea surface temperatures and proven to be an acute threat to corals and other reef-dwelling organisms. Short periods (days) of elevated sea surface temperatures by as little as 1–2°C above the normal maximum temperature has led to more frequent and more widespread episodes of coral bleaching-the expulsion of symbiotic algae. A more chronic consequence of increasing atmospheric CO2 is the lowering of pH of surface waters, which affects the rate at which corals and other reef organisms secrete and build their calcium carbonate skeletons. Average pH of the surface ocean has already decreased by an estimated 0.1 unit since preindustrial times, and will continue to decline in concert with rising atmospheric CO2. These climate-related Stressors combined with other direct anthropogenic assaults, such as overfishing and pollution, weaken reef organisms and increase their susceptibility to disease.

Author: Almo Farina
Publisher: John Wiley & Sons
ISBN: 1119230691
Category : Science
Languages : en
Pages : 367

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Book Description
The sounds produced by geophonic, biophonic and technophonic sources are relevant to the function of natural and human modified ecosystems. Passive recording is one of the most non-invasive technologies as its use avoids human intrusion during acoustic surveys and facilitates the accumulation of huge amounts of acoustical data. For the first time, this book collates and reviews the science behind ecoaucostics; illustrating the principles, methods and applications of this exciting new field. Topics covered in this comprehensive volume include; the assessment of biodiversity based on sounds emanating from a variety of environments the best technologies and methods necessary to investigate environmental sounds implications for climate change and urban systems the relationship between landscape ecology and ecoacoustics the conservation of soundscapes and the social value of ecoacoustics areas of potential future research. An invaluable resource for scholars, researchers and students, Ecoacoustics: The Ecological Role of Sounds provides an unrivalled set of ideas, tools and references based on the current state of the field.

Author: Julia Briand
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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"Coral reefs are composed of diverse taxa that support key ecosystem processes and functions. Specifically, large, complex and fast-growing coral species, such as Acropora, uphold ecosystem functioning through reef-building processes. Dominant coral species and other benthic taxa vary across natural inshore to offshore environmental gradients, along which lagoonal reefs and forereefs occur. While natural environmental gradients that shape reef composition and function remain intact in remote locations, confounding anthropogenic disturbances have altered environmental conditions, affecting reefs across space and time. For centuries, local anthropogenic disturbances have altered inshore conditions, reducing key coral species in lagoonal reefs. In recent decades, global anthropogenic disturbances have induced chronic thermal stress and bleaching events in reefs worldwide. As global anthropogenic disturbances increase, reefs that lack key reef-building species and can no longer maintain reef-building processes are more susceptible to degradation. Across the Caribbean, key reef-building corals, such as Acropora species, have been replaced by opportunistic or disturbance-tolerant corals, leading to the functional homogenization of reef communities. Such patterns in the decline of Acropora dominance across the Caribbean indicate that altered environmental gradients play a role in shaping reef response to increasing global anthropogenic disturbance. Here, we quantified spatio-temporal variation in the composition and function of 11 coral reefs along an inshore to offshore environmental gradient altered by anthropogenic disturbance in the Bocas del Toro archipelago, located along the Caribbean coast of Panama. Specifically, we assess spatial and temporal variation in benthic cover, coral species, and coral functional traits over a period of 15 years and 3 bleaching events. We found that lagoonal reefs and forereefs were distinct in composition and function, which can be attributed to natural and anthropogenically-sourced differences in environmental conditions. Additionally, we found that lagoonal reefs and forereefs became functionally homogenous over time and across 3 bleaching events. Specialist species with unique functional roles were likely replaced by opportunistic and generalist species that can tolerate or acclimate to novel environmental conditions. Overall, lagoonal reefs experienced greater declines in key coral species and diversity than forereefs likely due to the long-term impacts of local anthropogenic disturbances. In fact, functional diversity decreased 4x faster in lagoonal reefs than forereefs. Our results indicate that altered environmental gradients play a role in shaping reef composition and function, as well as reef response to increasing global anthropogenic disturbance. As such, management strategies that account for variation in reef composition and function across altered environmental conditions may more effectively protect coral reefs from the synergistic effects of both local and global anthropogenic disturbances, ensuring the persistence of reef-building processes and ecosystem function"--

Author: Clive R. Wilkinson
Publisher: IUCN
ISBN: 2831702046
Category : Climatic changes
Languages : en
Pages : 140

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A global overview of the potential impacts of climate change and sea level rise on coral reefs, and of the implications of such impacts for ecological sustainable use of coral reefs. Includes information on the status and trends of reef conservation and use around the world, and suggestions for management of reefs in a changing world.

Author: Benjamin Michael Fitzpatrick
Publisher:
ISBN:
Category :
Languages : en
Pages : 171

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[Truncated abstract] The goal of this work was to investigate the finescale habitat associations and determine the effect of human impacts on coral reef fish assemblages. Initially I investigate how finescale spatial habitat variation influences the distribution and abundance of coral reef fishes. Significant variation in the reef fish assemblage was driven by variation in habitat. Consequently finescale habitat variation needs be accounted for in spatial or temporal surveys of coral fish assemblages. My second question investigated how protection from fishing influences the overall variation in coral reef fish assemblages, while my third question investigated how consistent the differences in protected fish assemblages are through time. Protection from fishing accounted for significantly more variation in fish assemblages than that explained by finescale habitat alone. This was driven by an average abundance and length of target species being higher inside sanctuaries and a response in non-target species indicating that there are some trophic interactions occurring between fishes. I found that both target and non-target species can be more abundant at protected reefscapes through time, consistent with the theory that protected areas can achieve recovery and lasting maintenance of fish assemblage structure relative to adjacent fished locations. I also investigated how fish assemblages within shallow coral reef habitats differ to those of adjacent continental shelf habitats to a depth of 100m. Cross-shelf sampling produced significant new knowledge on the depth and habitat specificity of many species previously only known from shallow coral reef environments. Many target species protected by shallow water protected areas are found as adults in unpotected shelf waters suggesting shallow water protected areas alone may not be effective for all species equally. Expanded depth distributions for many species revealed some refuge at depth from shallow water climate related impacts, though it is uncertain how this might contribute to persistence in populations at a local or regional scale. Many species are confined to one or a few shallow water habitats for their entire post recruitment lifehistory as opposed to others that can range across many. Fish assemblages associated with deeper water habitats are composed of higher order predators and high numbers of unique species, suggesting they will respond very differently to shallow waters when impacted by fisheries. Diversity and unique species associated with deep water habitats approached those found at shallow coral reef habitats. Habitat specialization changes dramatically from species to species and was not easily predicted. This research holds a number of key implications. Firstly the design of coral reef marine protected areas and associated monitoring programs should account for variation in benthic habitat. Fishing and other human impacts affect significantly different elements of coral reef fish assemblages depending upon the biological and physical parameters of the benthic habitat found. Marine protected areas should incorporate this habitat variability wherever practical, as discrete elements of trophic structure were significantly associated with different habitats...

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Logan Douglas Wiwchar
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Coral reefs are the most diverse marine ecosystem, but are increasingly threatened by local and global anthropogenic changes. In this thesis, I examine the impact of local stressors on the spatial variability of coral reef fish community composition by modeling the !-diversity of 35 islands across the Pacific Ocean that are characterized by either low or high human disturbance. By examining !-diversity across three spatial scales (within island, within island group, and across island group), and using null models to control for differences in alpha-diversity or abundance, I reveal previously undocumented effects of human disturbance on coral reef fish assemblages. At all scales, human disturbances alter !-diversity. At the largest-scale, islands with high human disturbance have lower incidence- and abundance-based !-diversity, consistent with biotic homogenization. This pattern was driven by both species with high and low abundances that differed across islands. At the smaller two scales (within islands or island groups), the presence of low abundance species is more variable on islands with high human disturbance (manifest in greater incidence-based !-diversity), but these islands have lower abundance-based !- diversity driven by moderately abundant and widespread species. Multivariate techniques show that islands with high human disturbance have a weaker species-environment relationship, and as such, I suggest that homogenization of coral reef fish assemblages by human disturbances is resulting in greater stochasticity of species composition.