Coral species composition drives key ecosystem function on coral reefs

Rapid and unprecedented ecological change threatens the functioning and stability of ecosystems. On coral reefs, global climate change and local stressors are reducing and reorganizing habitat-forming corals and associated species, with largely unknown implications for critical ecosystem functions such as herbivory. Herbivory mediates coral–algal competition, thereby facilitating ecosystem recovery following disturbance such as coral bleaching events or large storms. However, relationships between coral species composition, the distribution of herbivorous fishes and the delivery of their functional impact are not well understood. Here, we investigate how herbivorous fish assemblages and delivery of two distinct herbivory processes, grazing and browsing, differ among three taxonomically distinct, replicated coral habitats. While grazing on algal turf assemblages was insensitive to different coral configurations, browsing on the macroalga Laurencia cf. obtusa varied considerably among habitats, suggesting that different mechanisms may shape these processes. Variation in browsing among habitats was best predicted by the composition and structural complexity of benthic assemblages (in particular the cover and composition of corals, but not macroalgal cover), and was poorly reflected by visual estimates of browser biomass. Surprisingly, the lowest browsing rates were recorded in the most structurally complex habitat, with the greatest cover of coral (branching Porites habitat). While the mechanism for the variation in browsing is not clear, it may be related to scale-dependent effects of habitat structure on visual occlusion inhibiting foraging activity by browsing fishes, or the relative availability of alternate dietary resources. Our results suggest that maintained functionality may vary among distinct and emerging coral reef configurations due to ecological interactions between reef fishes and their environment determining habitat selection.

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The evolution of traits and functions in herbivorous coral reef fishes through space and time

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2018.2672 ◽

2019 ◽

Vol 286 (1897) ◽

pp. 20182672 ◽

Cited By ~ 13

Author(s):

Alexandre C. Siqueira ◽

David R. Bellwood ◽

Peter F. Cowman

Keyword(s):

Coral Reefs ◽

Fish Assemblages ◽

Reef Fishes ◽

Ecosystem Functions ◽

Ecological Framework ◽

Functional Composition ◽

Ecological Process ◽

Wide Range ◽

The World ◽

Trait Space

Herbivory by fishes has been identified as a key ecological process shaping coral reefs through time. Although taxonomically limited, herbivorous reef fishes display a wide range of traits, which results in varied ecosystem functions on reefs around the world. Yet, we understand little about how these trait combinations and functions in ecosystems changed through time and across biogeographic realms. Here, we used fossils and phylogenies in a functional ecological framework to reveal temporal changes in nominally herbivorous fish assemblages among oceanic basins in both trait space and lineage richness among functions. We show that the trait space occupied by extant herbivorous fishes in the Indo-Pacific resulted from an expansion of traits from the ancestral Tethyan assemblages. By contrast, trait space in the Atlantic is the result of lineage turnover, with relatively recent colonization by lineages that arose in the east Tethys/Indo-Pacific. From an ecosystem function perspective, the Atlantic supports a depauperate fauna, with few extant herbivorous reef fish lineages performing each function. Indo-Pacific fishes support both more functions and more lineages within each function, with a marked Miocene to Pleistocene expansion. These disparities highlight the importance of history in explaining global variation in fish functional composition on coral reefs.

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Capture, Culture and Release of Postlarvae Fishes: Proof-of-Concept as a Tool Approach to Support Reef Management

Frontiers in Marine Science ◽

10.3389/fmars.2021.718526 ◽

2021 ◽

Vol 8 ◽

Author(s):

Camilo Cortés-Useche ◽

Williams Reyes-Gamboa ◽

José Luís Cabrera-Pérez ◽

Johanna Calle-Triviño ◽

Ana Cerón-Flores ◽

...

Keyword(s):

Fish Assemblages ◽

Reef Fishes ◽

Ecosystem Functions ◽

Caribbean Region ◽

Species Number ◽

Suitable Habitat ◽

Proof Of Concept ◽

Reef Management ◽

Great Opportunity ◽

Release Experiment

The changing world presents negative impacts on marine ecosystems and has led to the development of diversified tools to support reef restoration. Harnessing restoration to achieve success needs innovative techniques that also address the restoration of reef fish assemblages, contributing to the conservation of biodiversity and ecosystem functions and also tackle the cost-effectiveness through impact-driven solutions. Here, we propose a proof-of-concept for enhancing fish populations on reefs using: (1) postlarvae capture, (2) aquarium culture, and (3) release to reef sites. We conducted field studies in the Mexican Caribbean to analyze for the first time, the possibility of using the capture and aquarium culture of postlarvae fish species and release of juveniles as a tool for the potential recovery of reef biodiversity resilience. We tested the potential of postlarvae capture using two distinct night light traps (BOX and collect by artificial reef ecofriendly traps, C.A.R.E.) in three sampling sites with different distances from shoreline and depth. We collected 748 postlarvae reef fishes from eight orders, 20 families, and 40 species. Acanthuridae, Pomacentridae, Monacanthidae, and Tetraodontidae comprised the highest species number of postlarvae families. We also set up a pilot release experiment with Stegastes partitus using two trials (32 and 1 day after capture) and propose analysis to determine appropriate reef sites to release the cultured juveniles and to aid ecological planning. We present the results of the pilot release experiment with S. partitus, showing that there is a positive effect in survivorship during the capture (80%) and release (76–100%) procedures into suitable habitat and good chance that more studies will bring novelty to the field. Although trials carried out with more species relevant to restoration will be needed. The use of these techniques can be a great opportunity to improve the research of restoration efforts in the Caribbean region with fish-depleted coral reefs with vulnerable food webs, especially at local scales and supporting other management strategies.

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Unexpected high vulnerability of functions in wilderness areas: evidence from coral reef fishes

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2016.0128 ◽

2016 ◽

Vol 283 (1844) ◽

pp. 20160128 ◽

Cited By ~ 24

Author(s):

Stéphanie D'agata ◽

Laurent Vigliola ◽

Nicholas A. J. Graham ◽

Laurent Wantiez ◽

Valeriano Parravicini ◽

...

Keyword(s):

Species Richness ◽

Coral Reef ◽

Fish Assemblages ◽

New Caledonia ◽

Reef Fishes ◽

French Polynesia ◽

Ecosystem Functions ◽

Large Species ◽

Wilderness Areas ◽

High Species Richness

High species richness is thought to support the delivery of multiple ecosystem functions and services under changing environments. Yet, some species might perform unique functional roles while others are redundant. Thus, the benefits of high species richness in maintaining ecosystem functioning are uncertain if functions have little redundancy, potentially leading to high vulnerability of functions. We studied the natural propensity of assemblages to be functionally buffered against loss prior to fishing activities, using functional trait combinations, in coral reef fish assemblages across unfished wilderness areas of the Indo-Pacific: Chagos Archipelago, New Caledonia and French Polynesia. Fish functional diversity in these wilderness areas is highly vulnerable to fishing, explained by species- and abundance-based redundancy packed into a small combination of traits, leaving most other trait combinations (60%) sensitive to fishing, with no redundancy. Functional vulnerability peaks for mobile and sedentary top predators, and large species in general. Functional vulnerability decreases for certain functional entities in New Caledonia, where overall functional redundancy was higher. Uncovering these baseline patterns of functional vulnerability can offer early warning signals of the damaging effects from fishing, and may serve as baselines to guide precautionary and even proactive conservation actions.

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Ecological and morphological traits predict depth-generalist fishes on coral reefs

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2015.2332 ◽

2016 ◽

Vol 283 (1823) ◽

pp. 20152332 ◽

Cited By ~ 32

Author(s):

Tom C. L. Bridge ◽

Osmar J. Luiz ◽

Richard R. Coleman ◽

Corinne N. Kane ◽

Randall K. Kosaki

Keyword(s):

Aspect Ratio ◽

Coral Reefs ◽

Fish Assemblages ◽

Reef Fishes ◽

Food Sources ◽

Ecological Communities ◽

Functional Convergence ◽

Geographical Distances ◽

Depth Preference ◽

Lower Light

Ecological communities that occupy similar habitats may exhibit functional convergence despite significant geographical distances and taxonomic dissimilarity. On coral reefs, steep gradients in key environmental variables (e.g. light and wave energy) restrict some species to shallow depths. We show that depth-generalist reef fishes are correlated with two species-level traits: caudal fin aspect ratio and diet. Fishes with high aspect ratio (lunate) caudal fins produce weaker vortices in the water column while swimming, and we propose that ‘silent swimming’ reduces the likelihood of detection and provides an advantage on deeper reefs with lower light irradiance and water motion. Significant differences in depth preference among trophic guilds reflect variations in the availability of different food sources along a depth gradient. The significance of these two traits across three geographically and taxonomically distinct assemblages suggests that deep-water habitats exert a strong environmental filter on coral reef-fish assemblages.

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Strong ‘functional’ divergence of tropical reef fish assemblages along the global diversity gradient

10.1101/2020.09.18.303008 ◽

2020 ◽

Author(s):

V Parravicini ◽

MG Bender ◽

S Villéger ◽

F Leprieur ◽

L Pellissier ◽

...

Keyword(s):

Coral Reefs ◽

Fish Assemblages ◽

Human Impacts ◽

Functional Divergence ◽

Biodiversity Loss ◽

Reef Fishes ◽

Climatic Conditions ◽

Taxonomic Structure ◽

Distribution Models ◽

Diversity Gradient

AbstractCoral reefs are experiencing declines due to climate change and local human impacts. While at local scale biodiversity loss induces shifts in community structure, previous biogeographical analyses recorded consistent taxonomic structure of fish communities across global coral reefs. This suggest that regional communities represent a random subset of the global species and traits pool, whatever their species richness. Using distributional data on 3,586 fish species and latest advances in species distribution models we show that the global distribution of reef fishes is influenced by two major traits (body size and diet) and produces a strong divergence in the trait structure of assemblages across the biodiversity gradient. This divergence is best explained by the isolation of reefs during past unfavorable climatic conditions and highlights the risk of a global community re-organization if the ongoing climate-induced reef fragmentation is not halted.

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Regional heterogeneity in coral species richness and hue reveals novel global predictors of reef fish intra-family diversity

Scientific Reports ◽

10.1038/s41598-021-97862-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Kieran D. Cox ◽

Mackenzie B. Woods ◽

Thomas E. Reimchen

Keyword(s):

Species Richness ◽

Coral Species ◽

Fish Assemblages ◽

Terrestrial Ecosystems ◽

Reef Fishes ◽

Regional Heterogeneity ◽

Biological Communities ◽

Family Diversity ◽

Coral Reef Ecosystems ◽

Intra Family

AbstractHabitat heterogeneity shapes biological communities, a well-known process in terrestrial ecosystems but substantially unresolved within coral reef ecosystems. We investigated the extent to which coral richness predicts intra-family fish richness, while simultaneously integrating a striking aspect of reef ecosystems—coral hue. To do so, we quantified the coral richness, coral hue diversity, and species richness within 25 fish families in 74 global ecoregions. We then expanded this to an analysis of all reef fishes (4465 species). Considering coral bleaching as a natural experiment, we subsequently examined hue's contribution to fish communities. Coral species and hue diversity significantly predict each family's fish richness, with the highest correlations (> 80%) occurring in damselfish, butterflyfish, emperors and rabbitfish, lower (60–80%) in substrate-bound and mid-water taxa such as blennies, seahorses, and parrotfish, and lowest (40–60%) in sharks, morays, grunts and triggerfish. The observed trends persisted globally. Coral bleaching's homogenization of reef colouration revealed hue’s contribution to maintaining fish richness, abundance, and recruit survivorship. We propose that each additional coral species and associated hue provide added ecological opportunities (e.g. camouflage, background contrast for intraspecific display), facilitating the evolution and co-existence of diverse fish assemblages.

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Spatial assemblage structure of shallow-water reef fish in Southwest Australia

Marine Ecology Progress Series ◽

10.3354/meps13445 ◽

2020 ◽

Vol 649 ◽

pp. 125-140

Author(s):

DS Goldsworthy ◽

BJ Saunders ◽

JRC Parker ◽

ES Harvey

Keyword(s):

Shallow Water ◽

Reef Fish ◽

Marine Environment ◽

Fish Assemblages ◽

Canopy Cover ◽

Reef Fishes ◽

Reef Fish Assemblage ◽

Reef Type ◽

Present Distribution ◽

Southwest Australia

Bioregional categorisation of the Australian marine environment is essential to conserve and manage entire ecosystems, including the biota and associated habitats. It is important that these regions are optimally positioned to effectively plan for the protection of distinct assemblages. Recent climatic variation and changes to the marine environment in Southwest Australia (SWA) have resulted in shifts in species ranges and changes to the composition of marine assemblages. The goal of this study was to determine if the current bioregionalisation of SWA accurately represents the present distribution of shallow-water reef fishes across 2000 km of its subtropical and temperate coastline. Data was collected in 2015 using diver-operated underwater stereo-video surveys from 7 regions between Port Gregory (north of Geraldton) to the east of Esperance. This study indicated that (1) the shallow-water reef fish of SWA formed 4 distinct assemblages along the coast: one Midwestern, one Central and 2 Southern Assemblages; (2) differences between these fish assemblages were primarily driven by sea surface temperature, Ecklonia radiata cover, non-E. radiata (canopy) cover, understorey algae cover, reef type and reef height; and (3) each of the 4 assemblages were characterised by a high number of short-range Australian and Western Australian endemic species. The findings from this study suggest that 4, rather than the existing 3 bioregions would more effectively capture the shallow-water reef fish assemblage patterns, with boundaries having shifted southwards likely associated with ocean warming.

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The concept of local explosion in freshwater ecosystems

Ecology and Noospherology ◽

10.15421/031413 ◽

2013 ◽

Vol 25 (1-2) ◽

pp. 136-148

Author(s):

I. V. Gryb

Keyword(s):

Species Composition ◽

Aquatic Environment ◽

Arid Zone ◽

Fish Fauna ◽

River Basins ◽

Freshwater Ecosystems ◽

Human Society ◽

Living Matter ◽

Ecosystem Recovery ◽

Average Temperature

The concept of an explosion in freshwater ecosystems as a result of the release of accumulated energy, accompanied by the destruction of the steady climax successions of hydrocenoses is presented. The typification of local explosions as well as methods for assessing their risk during the development of river basins are shown. The change in atmospheric circulation, impaired phases of the hydrological regime of rivers, increasing the average temperature of the planet, including in Polesie to 0,6 ºC, deforestation leads to concentration and release of huge amounts of unmanaged terrestrial energy, which manifests itself in the form of disasters and emergencies. Hydroecological explosion is formed as a result of multifactorial external influence (natural and anthropogenic) on the water body in a certain period of time. Moreover, its level at wastewater discharge depends on the mass of recycled impurities and behaved processing capacity of the reservoir, and the mass of dumped on biocides and the possibility of the water flow to their dilution and to the utilization of non-toxic concentrations. In all these cases the preservation of "centers of life" in the tributaries of the first order – local fish reproduction areas contributed to ecosystem recovery, and the entire ecosystem has evolved from equilibrium to non-equilibrium with further restructuring after the explosion and environmental transition to a new trophic level. It means that hydroecological explosion can be researched as the logical course of development of living matter in abiotic environmental conditions, ending abruptly with the formation of new species composition cenoses and new bio-productivity. The buffer capacity of the water environment is reduced due to re-development and anthropic transformation of geobiocenoses of river basins, which leads to a weakening of life resistance. This applies particularly to the southern industrial regions of Ukraine, located in the arid zone that is even more relevant in the context of increased average temperature due to the greenhouse effect, as well as to Polesie (Western, Central and Chernihiv), had been exposed to large-scale drainage of 60-80th years, which contributed to the degradation of peatlands and fitostroma. Imposing the western trace of emissions from the Chernobyl accident to these areas had created the conditions of prolonged hydroecological explosion in an intense process of aging water bodies, especially lakes, change in species composition of fish fauna and the occurrence of neoplasms at the organismal level. Under these conditions, for the existence of man and the environment the vitaukta should be strengthened, i.e. buffer resistance and capacitance the aquatic environment, bioefficiency on the one hand and balanced using the energy deposited - on the other. This will restore the functioning of ecosystems "channel-floodplain", "riverbed-lake", reducing the energy load on the aquatic environment. Hydroecological explosions of natural origin can not be considered a pathology – it is a jump process of natural selection of species of biota. Another thing, if they are of anthropogenic origin and if the magnitude of such an impact is on the power of geological factors. Hydroecological explosions can be regarded as a manifestation of environmental wars that consciously or unconsciously, human society is waging against themselves and their kind in the river basins, so prevention of entropy increase in the aquatic environment and the prevention of hydroecological explosions is a matter of human survival. While the man - is not the final link in the development of living matter, it can develop without him, as matter is eternal, and the forms of its existence are different.

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