Coral Reef Biodiversity Research Articles

Additive Diversity Partitioning of Fish in a Caribbean Coral Reef Undergoing Shift Transition

Shift transitions in dominance on coral reefs from hard coral cover to fleshy macroalgae are having negative effects on Caribbean coral reef communities. Data on spatiotemporal changes in biodiversity during these modifications are important for decision support for coral reef biodiversity protection. The main objective of this study is to detect the spatiotemporal patterns of coral reef fish diversity during this transition using additive diversity-partitioning analysis. We examined α, β and γ fish diversity from 2000 to 2010, during which time a shift transition occurred at Mahahual Reef, located in Quintana Roo, Mexico. Data on coral reef fish and benthic communities were obtained from 12 transects per geomorphological unit (GU) in two GUs (reef slope and terrace) over six years (2000, 2005, 2006, 2007, 2008, 2010). Spatial analysis within and between the GUs indicated that the γ-diversity was primarily related to higher β-diversity. Throughout the six study years, there were losses of α, β and γ-diversity associated spatially with the shallow (reef slope) and deeper (reef terrace) GUs and temporally with the transition in cover from mound corals to fleshy macroalgae and boulder corals. Despite a drastic reduction in the number of species over time, β-diversity continues to be the highest component of γ-diversity. The shift transition had a negative effect on α, β and γ-diversity, primarily by impacting rare species, leading a group of small and less vulnerable fish species to become common and an important group of rare species to become locally extinct. The maintenance of fish heterogeneity (β-diversity) over time may imply the abetment of vulnerability in the face of local and global changes.

ReefBahia, an integrated GIS approach for coral reef conservation in Bahia, Brazil

Coral reefs around the world are facing serious threats. These fragile ecosystems are in need for conservation. The coastal state of Bahia hosts the most extensive and richest area of coral reefs in the South Atlantic Ocean. Assessment, planning and management of coral reef ecosystems are particularly challenging tasks. This work shows how the creation of a GIS improves the process of management, monitoring and conservation of the Bahian reef environments The initial data input started by the vectorization of 1) bathymetric data from the Bureau of Hydrography and Navigation (DHN), 2) shoreline and mangrove areas from Landsat 7 ETM + images, 3) near surface reefs from Quickbird images, and 4) coastal and marine protected areas of federal, state and local administrations. Geological, physical, biological and social information was then included in order to create a suitable marine GIS for conservation aims. The data includes information on sediment granulometry and transport patterns, rocky substrate outcrops, sea surface temperature, wave direction, rain precipitation, major contributing river discharge, artisanal fishery, benthic cover and bleaching data. ReefBahia GIS has provided essential information for a better understanding of coral reefs of the state of Bahia geological and ecological characteristics such as mapping, representation, connectivity and biodiversity of coral reefs, geological facies, Quaternary sedimentation, numeric modeling of wave refraction and monitoring of bleaching events.

High adenylyl cyclase activity and in vivo cAMP fluctuations in corals suggest central physiological role.

Corals are an ecologically and evolutionarily significant group, providing the framework for coral reef biodiversity while representing one of the most basal of metazoan phyla. However, little is known about fundamental signaling pathways in corals. Here we investigate the dynamics of cAMP, a conserved signaling molecule that can regulate virtually every physiological process. Bioinformatics revealed corals have both transmembrane and soluble adenylyl cyclases (AC). Endogenous cAMP levels in live corals followed a potential diel cycle, as they were higher during the day compared to the middle of the night. Coral homogenates exhibited some of the highest cAMP production rates ever to be recorded in any organism; this activity was inhibited by calcium ions and stimulated by bicarbonate. In contrast, zooxanthellae or mucus had >1000-fold lower AC activity. These results suggest that cAMP is an important regulator of coral physiology, especially in response to light, acid/base disturbances and inorganic carbon levels.

Facilitation of coral reef biodiversity and health by cave sponge communities

Marine caves are understudied ecosystems that are frequently associated with coral reef communities; many are tidally influenced and may host a highly diverse sponge fauna. Although each cave represents a distinct habitat likely structured by site-specific hydrographic processes, a more complete understanding of the ecology of these communities requires com parative studies. Based on a gradient of sponge cover within 5 Bahamian caves, we conducted a natural experiment in sponge-derived nutrient enrichment of nearby patch reefs. We tested the hypothesis that water exiting the cave during low tide provides a nutrient-rich resource that facilitates the diversity and health of nearby reef communities. The percent cover and diversity of corals surrounding the openings of caves were significantly higher than in similar habitats farther removed from these communities. There was a significant correlation between percent sponge cover within the caves and nitrate concentrations in seawater flowing out of the caves, and δ15N stable isotope signatures indicated enrichment of the nearby reefs by sponge-derived nitrate. Zooxanthellae abundance and total protein concentration were higher in corals from reefs near cave entrances, suggesting that those corals benefited more from cave nutrients than did corals farther from cave openings. In addition to corals, percent algal cover increased near cave entrances, but these potential competitors of corals were kept in check by increased levels of herbivory relative to sites removed from cave mouths. As global environmental changes continue to impact coral reef ecosystems, diversity ‘hot spots’, such as these marine caves, could serve as refuges and ‘seedbanks’ for nearby dwindling reef habitats.

Coral Reef Resilience through Biodiversity

Irrefutable evidence of coral reef degradation worldwide and increasing pressure from rising seawater temperatures and ocean acidification associated with climate change have led to a focus on reef resilience and a call to “manage” coral reefs for resilience. Ideally, global action to reduce emission of carbon dioxide and other greenhouse gases will be accompanied by local action. Effective management requires reduction of local stressors, identification of the characteristics of resilient reefs, and design of marine protected area networks that include potentially resilient reefs. Future research is needed on how stressors interact, on how climate change will affect corals, fish, and other reef organisms as well as overall biodiversity, and on basic ecological processes such as connectivity. Not all reef species and reefs will respond similarly to local and global stressors. Because reef-building corals and other organisms have some potential to adapt to environmental changes, coral reefs will likely persist in spite of the unprecedented combination of stressors currently affecting them. The biodiversity of coral reefs is the basis for their remarkable beauty and for the benefits they provide to society. The extraordinary complexity of these ecosystems makes it both more difficult to predict their future and more likely they will have a future.

Sponge bioerosion on reef-building corals: Dependent on the environment or on skeletal density?

X-radiographic techniques were used to measure the skeletal density and percentage of bioerosion in Montastraea annularis and Porites astreoides growing in reefs subjected to suboptimal (Veracruz Reef System, VRS) and optimal (Mahahual, MH) environmental conditions for coral reef development. Skeletal density was higher in P. astreoides than in M. annularis and was higher in corals from MH than from the VRS. The percentage of the skeleton excavated by boring sponges was significantly correlated with skeletal density. These results are the first contribution that seeks to understand the interactions of the environment and coral skeletal density on sponge bioerosion and suggest that bioerosion is linked to coral skeletal density rather than to environmental conditions. Finally, based on the differences in growth strategies between the two species, the effects of climate change on sponge bioerosion rates could have repercussions on coral reef biodiversity and community structure.

Lithothamnion steneckii sp. nov. and Pneophyllum conicum: new coralline red algae (Corallinales, Rhodophyta) for coral reefs of Brazil

Nongeniculate coralline red algae are a common element of the Brazilian coastal zone, especially associated to coral reefs. During the course of ecological studies at Parque Municipal Marinho do Recife de Fora, two species of non-geniculate Corallinales were the major organisms covering the reef. Analyses of the vegetative and reproductive features of the species were analyzed; indicating that one new species of the genus Lithothamnion is proposed here based on the combination of several features associated with anatomy of the tetrasporangial conceptacles in relation to other species of the genus for which modern accounts are available. This new proposal along with other new species, new combinations and range extension of some species of the genus based in similar features clearly suggest that stability in species delimitation is possible. The second species found Pneophyllum conicum represents a range extension of more than 6,000 km from the Pacific in to the Atlantic Ocean suggesting that some nongeniculate species are widely distributed. The occurrence and abundance of these species supports and emphasizes the need for an extensive taxonomic reassessment of coralline red algae in the context of Brazilian coral reef biodiversity.

Submerged banks in the Great Barrier Reef, Australia, greatly increase available coral reef habitat

Abstract Harris, P. T., Bridge, T. C. L., Beaman, R. J., Webster, J. M., Nichol, S. L., and Brooke, B. P. 2013. Submerged banks in the Great Barrier Reef, Australia, greatly increase available coral reef habitat. – ICES Journal of Marine Science, 70: 284–293. Anthropogenic global ocean warming is predicted to cause bleaching of many near-sea-surface (NSS) coral reefs, placing increased importance on deeper reef habitats to maintain coral reef biodiversity and ecosystem function. However, the location and spatial extent of many deep reef habitats is poorly known. The question arises: how common are deep reef habitats in comparison with NSS reefs? We used a dataset from the Great Barrier Reef (GBR) to show that only about 39% of available seabed on submerged banks is capped by NSS coral reefs (16 110 km2); the other 61% of bank area (25 600 km2) is submerged at a mean depth of around 27 m and represents potential deep reef habitat that is spatially distributed along the GBR continental shelf in the same latitudinal distribution as NSS reefs. Out of 25 600 km2 of submerged bank area, predictive habitat modelling indicates that more than half (around 14 000 km2) is suitable habitat for coral communities.

A comparison of proxy performance in coral biodiversity monitoring

The productivity and health of coral reef hab- itat is diminishing worldwide; however, the effect that habitat declines have on coral reef biodiversity is not known. Logistical and financial constraints mean that sur- veys of hard coral communities rarely collect data at the species level; hence it is important to know if there are proxy metrics that can reliably predict biodiversity. Here, the performances of six proxy metrics are compared using regression analyses on survey data from a location in the northern Great Barrier Reef. Results suggest generic rich- ness is a strong explanatory variable for spatial patterns in species richness (explaining 82 % of the variation when measured on a belt transect). The most commonly used metric of reef health, percentage live coral cover, is not positively or linearly related to hard coral species richness. This result raises doubt as to whether management actions based on such reefscape information will be effective for the conservation of coral biodiversity.

Consumer Preferences Toward Marine Tourism Area

The marine zone tourism is growing attracting more tourists. Pramuka Island is marine conservation area enriched with marine biodiversity in coral reefs and other natural resources. To develop this potential tourist destination, a customer-based marketing program is required to attract domestic and foreign tourists. The main vision is to understand tourist preferences for marine tourism activities and facilities. A research was conducted on Pramuka Island as a well-known marine tourism zone. The objective was to determine the key tourist preferences for marine tourism destination. Research methods utilized Cochran Q test and Conjoint analysis where the primary data were obtained from tourist respondents. The result showed that there was a tourist preference based on the five attributes considered most important, namely tourism activities, tourist attractions, types of accommodation, food and souvenirs types. This study provided marine tourism destination management with useful guidance for broader implications of the implementation of marketing programs and tourism attraction. Moreover, the results of this study consolidated the learning of a variety of academic and industrial research papers in particular for the measurement of customer preferences towards marine tourism destination.

Small change, big difference: Sea surface temperature distributions for tropical coral reef ecosystems, 1950–2011

Changes in tropical sea surface temperature (SST) are examined over the period 1950–2011 during which global average temperature warmed by 0.4°C. Average tropical SST is warming about 70% of the global average rate. Spatially, significant warming between the two time periods, 1950–1980 and 1981–2011, has occurred across 65% of the tropical oceans. Coral reef ecosystems occupy 10% of the tropical oceans, typically in regions of warmer (+1.8°C) and less variable SST (80% of months within 3.3°C range) compared to non‐reef areas (80% of months within 7.0°C range). SST is a primary controlling factor of coral reef distribution and coral reef organisms have already shown their sensitivity to the relatively small amount of warming observed so far through, for example, more frequent coral bleaching events and outbreaks of coral disease. Experimental evidence is also emerging of possible thermal thresholds in the range 30°C–32°C for some physiological processes of coral reef organisms. Relatively small changes in SST have already resulted in quite large differences in SST distribution with a maximum ‘hot spot’ of change in the near‐equatorial Indo‐Pacific which encompasses both the Indo‐Pacific warm pools and the center of coral reef biodiversity. Identification of this hot spot of SST change is not new but this study highlights its significance with respect to tropical coral reef ecosystems. Given the modest amount of warming to date, changes in SST distribution are of particular concern for coral reefs given additional local anthropogenic stresses on many reefs and ongoing ocean acidification likely to increasingly compromise coral reef processes.

Fish biodiversity in coral reefs and lagoon at the Maratua Island, East Kalimantan

Madduppa HH, Agus SB, Farhan AR, Suhendra D, Subhan B. 2012. Fish biodiversity in coral reefs and lagoon at the Maratua Island, East Kalimantan. Biodiversitas 13: 145-150. Fishes are one of the most important biotic components in the aquatic environment. They are filling different habitats, including coral reef and lagoon. This study aims to (i) assess biodiversity in coral reef and lagoon in Maratua Island, East Kalimantan, and (ii) compare the fish community indices (Shannon-Wiener diversity, Evenness, and Dominance) between the coral reef and lagoon. A total of 159 fish species of belonging to 30 families were observed during five visual census of the study period. The number of species on coral reefs is higher (121 species) than in the lagoons (47 species). Relative abundance (%) of each species also varied and did not form a specific pattern. However, a clear cluster between the coral reef and lagoon habitats fromfish relative abundance based on multivariate analysis and dendogram Bray-Curtis Similarity was revealed. The Evenness index value (E) ranged from 0.814 to 0.874, the dominance index (C) ranged from 0.023 to 0.184, and the Shannon-Wiener diversity index (ln base, H') ranged from 1.890 to 4.133. Fish biodiversity in coral reefs was higher (H'= 3.290±0.301) than in the lagoon (H' = 2.495±0.578).

Trophic specialization influences the rate of environmental niche evolution in damselfishes (Pomacentridae)

The rate of environmental niche evolution describes the capability of species to explore the available environmental space and is known to vary among species owing to lineage-specific factors. Trophic specialization is a main force driving species evolution and is responsible for classical examples of adaptive radiations in fishes. We investigate the effect of trophic specialization on the rate of environmental niche evolution in the damselfish, Pomacentridae, which is an important family of tropical reef fishes. First, phylogenetic niche conservatism is not detected in the family using a standard test of phylogenetic signal, and we demonstrate that the environmental niches of damselfishes that differ in trophic specialization are not equivalent while they still overlap at their mean values. Second, we estimate the relative rates of niche evolution on the phylogenetic tree and show the heterogeneity among rates of environmental niche evolution of the three trophic groups. We suggest that behavioural characteristics related to trophic specialization can constrain the evolution of the environmental niche and lead to conserved niches in specialist lineages. Our results show the extent of influence of several traits on the evolution of the environmental niche and shed new light on the evolution of damselfishes, which is a key lineage in current efforts to conserve biodiversity in coral reefs.

An annotated list of fish parasites (Isopoda, Copepoda, Monogenea, Digenea, Cestoda, Nematoda) collected from Snappers and Bream (Lutjanidae, Nemipteridae, Caesionidae) in New Caledonia confirms high parasite biodiversity on coral reef fish.

BackgroundCoral reefs are areas of maximum biodiversity, but the parasites of coral reef fishes, and especially their species richness, are not well known. Over an 8-year period, parasites were collected from 24 species of Lutjanidae, Nemipteridae and Caesionidae off New Caledonia, South Pacific.ResultsHost-parasite and parasite-host lists are provided, with a total of 207 host-parasite combinations and 58 parasite species identified at the species level, with 27 new host records. Results are presented for isopods, copepods, monogeneans, digeneans, cestodes and nematodes. When results are restricted to well-sampled reef fish species (sample size > 30), the number of host-parasite combinations is 20–25 per fish species, and the number of parasites identified at the species level is 9–13 per fish species. Lutjanids include reef-associated fish and deeper sea fish from the outer slopes of the coral reef: fish from both milieus were compared. Surprisingly, parasite biodiversity was higher in deeper sea fish than in reef fish (host-parasite combinations: 12.50 vs 10.13, number of species per fish 3.75 vs 3.00); however, we identified four biases which diminish the validity of this comparison. Finally, these results and previously published results allow us to propose a generalization of parasite biodiversity for four major families of reef-associated fishes (Lutjanidae, Nemipteridae, Serranidae and Lethrinidae): well-sampled fish have a mean of 20 host-parasite combinations per fish species, and the number of parasites identified at the species level is 10 per fish species.ConclusionsSince all precautions have been taken to minimize taxon numbers, it is safe to affirm than the number of fish parasites is at least ten times the number of fish species in coral reefs, for species of similar size or larger than the species in the four families studied; this is a major improvement to our estimate of biodiversity in coral reefs. Our results suggest that extinction of a coral reef fish species would eventually result in the coextinction of at least ten species of parasites.

Perceptions of climate change risks and resilient island planning in the Maldives

This article explores the drivers, benefits, and challenges facing climate change adaptation in the Maldives. It specifically investigates the “Integrating Climate Change Risks into Resilient Island Planning in the Maldives” Program, or ICCR, a four-year $9.3 million adaptation project being funded by the Least Developed Countries Fund, Maldivian Government and the United Nations Development Program, and nationally executed by the Ministry of Housing, Transport and Environment of the Maldivian Government. The article asks: what is the perception of coastal adaptation in the Maldives, and what are the potential contributions from the ICCR project? To answer this question, the article summarizes eight primary sectors vulnerable to climate change in the Maldives: human settlements, critical infrastructure, tourism, fisheries, health systems, water, food security, and coral reef biodiversity. It then describes the genesis and background behind the ICCR, which addresses many of these vulnerabilities by demonstrating coastal protection measures. Benefits to the ICCR include improving physical resilience by deploying “soft” infrastructure, institutional resilience by training policymakers and enhancing good governance, and community resilience by strengthening community assets and awareness. Challenges include ensuring that adaptation efforts are enough to truly respond to climate vulnerability, lack of coordination, and short-term thinking among business and community leaders.

Island endemism, morphological stasis, and possible cryptic speciation in two coral reef, commensal Leucothoid amphipod species throughout Florida and the Caribbean

Coral reefs are believed to be one of the most diverse ecosystems, but the true magnitude of their biodiversity and patterns of endemism is uncertain. This uncertainty stems partly from the relative paucity of investigations on the small, difficult to collect taxa (cryptofauna) that may make up the majority of reef biodiversity and require specialized expertise for morphological identification. To assess the extent of diversity in some of the reef micro-cryptofauna, we analyzed 414 bp of the mitochondrial cytochrome oxidase subunit I gene from 556 individuals representing two brooding amphipod species (Leu- cothoe ashleyae and Leucothoe kensleyi). These amphipods are commensal inside the branching vase sponge Callyspongia vaginalis, and were sampled throughout Florida and the Caribbean. Phylogenetic analyses revealed 11 deeply divergent, strongly supported lineages (seven L. ashleyae and four L. kensleyi) each with very narrow geographic ranges. The level of intraspecific lineage divergence for both morphospecies was among the highest reported for any marine crustacean (12.4-26.0% uncorrected), and exceeded that of congeners from nine diverse amphipod families, as well as the patristic genetic distance suggested as a threshold for crustacean species delineation. These findings suggest a his- tory of cryptic speciation within each morphospecies, concomitant with a pronounced period of morphological stasis involving each of the morphotypes. The observation of multiple, highly divergent, evolutionary significant units, each endemic to Florida and Caribbean island locations, supports the emerging view that coral reef biodiversity, especially in the cryptofaunal component, is likely vastly underestimated.

Review on hard coral recruitment (Cnidaria: Scleractinia) in Colombia

<p><strong>Abstract</strong></p><p>Recruitment, defined and measured as the incorporation of new individuals (i.e. coral juveniles) into a population, is a fundamental process for ecologists, evolutionists and conservationists due to its direct effect on population structure and function. Because most coral populations are self-feeding, a breakdown in recruitment would lead to local extinction. Recruitment indirectly affects both renewal and maintenance of existing and future coral communities, coral reef biodiversity (bottom-up effect) and therefore coral reef resilience. This process has been used as an indirect measure of individual reproductive success (fitness) and is the final stage of larval dispersal leading to population connectivity. As a result, recruitment has been proposed as an indicator of coral-reef health in marine protected areas, as well as a central aspect of the decision-making process concerning management and conservation. The creation of management plans to promote impact mitigation, rehabilitation and conservation of the Colombian coral reefs is a necessity that requires firstly, a review and integration of existing literature on scleractinian coral recruitment in Colombia and secondly, larger scale field studies. This motivated us to summarize and analyze all existing information on coral recruitment to determine the state of knowledge, isolate patterns, identify gaps, and suggest future lines of research.</p><p><strong>Key words: </strong>Recruitment, juvenile, coral, Scleractinia, structure, reef, Colombia, density, richness, monitoring.</p><p> </p>

Predicting spatially explicit coral reef fish abundance, richness and Shannon–Weaver index from habitat characteristics

The assessment of biodiversity in coral reefs requires the application of geographic information systems (GIS), remote sensing and analytical tools in order to make cost-effective spatially explicit predictions of biodiversity over large geographic areas. Here we present a spatially explicit prediction for coral reef fish diversity index, as well as habitat classification according to reef fish diversity index values in Chinchorro Bank Biosphere Reserve, one of the most important plain/atoll type reef systems in the Caribbean. We have used extensive ecological data on depth, fish and habitat characteristics to perform such prediction. Fish species assemblages and different biotic variables of benthic organisms were characterized using visual censuses and video-transects, respectively at 119 sampling stations. The information was integrated in a GIS, along with satellite imagery (LANSDAT 7 ETM+) and a digital bathymetric model. From the recorded data and a hierarchical classification procedure, we obtained nine different classes of habitats. We used a generalized regression analysis and spatial prediction methodology to create predictive maps (GIS layers) of the different reef benthic components, and a second modeling run produced predictive maps of coral reef fish diversity index. Predictive accuracy of the diversity index map presented a good correlation coefficient (r = 0.87), with maximum diversity index values en reefscapes composed of aggregation of coral colonies with seagrass beds. The implementation of our application was successful for the prediction of fish diversity hot spots and surrogate habitats.

Molecules, Morphology, Fossils and the Origination and Extinction Dynamics of Scleractinian Corals

The history of Scleractinian corals, richly documented by the fossil record, is one of complex dynamics linked to the dynamics of coral reefs themselves. In spite of all the waxing and waning of marine biodiversity throughout the post-Paleozoic, scleractinians have remained remarkably resilient as a lineage and have traversed two mass extinctions and repeated episodes of global change before becoming the chief builders of modern coral reefs. Understanding this history becomes all the more relevant in face of the current human driven coral reef biodiversity crisis. The advent of molecular phylogenetics has changed our perspective of those dynamics because it has uncovered pervasive morphological convergence in traditionally used taxonomic characters, revealing that the current classification is highly artificial. Taxonomy not only obscures important patterns, but also introduces artifacts into estimates of origination and extinction obtained directly from the fossil record. I present a brief review of the impact of molecular phylogenetics on the current understanding of coral evolution, with emphasis on the recently uncovered phyletic link between photosymbiotic, reef dwelling and azooxanthellate, deepwater coral biota. Then, I discuss the role of molecular-based techniques in a future research agenda of the evolutionary dynamics of the order. The greatest challenge for the future is the re-assessment of morphological characters from a cladistic perspective so that extinct and extant species are integrated in a unified phylogenetic framework, allowing rigorous testing of hypotheses on the fascinating biodiversity dynamics of the order.

Using DNA Barcoding and Standardized Sampling to Compare Geographic and Habitat Differentiation of Crustaceans: A Hawaiian Islands Example

Recently, the Census of Marine Life has explored methods to assess coral reef diversity by combining standardized sampling (to permit comparison across sites) with molecular techniques (to make rapid counts of species possible). To date, this approach has been applied across geographically broad scales (seven sites spanning the Indian, Pacific and Atlantic Oceans), focusing on similar habitats at all sites (10–12 m forereef). Here we examine crustacean spatial diversity patterns for a single atoll, comparing results for four sites (comprising forereef, backreef, and lagoon habitats) at French Frigate Shoals (FFS), Northwestern Hawaiian Islands, Hawaii, USA, within the Papahanaumokuakea Marine National Monument. The Bray-Curtis index of similarity across these habitats at FFS was the same or greater than the similarity between similar habitats on Heron Island and Lizard Island in the Great Barrier Reef and much greater than similarity between more widely separated localities in the Indo-Pacific Ocean (e.g., Ningaloo, Moorea, French Polynesia or the Line Islands). These results imply that, at least for shallow reefs, sampling multiple locations versus sampling multiple habitats within a site maximizes the rate at which we can converge on the best global estimate of coral reef biodiversity.