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

2016 ◽  
Vol 283 (1823) ◽  
pp. 20152332 ◽  
Author(s):  
Tom C. L. Bridge ◽  
Osmar J. Luiz ◽  
Richard R. Coleman ◽  
Corinne N. Kane ◽  
Randall K. Kosaki

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.

2020 ◽  
Vol 287 (1921) ◽  
pp. 20192214 ◽  
Author(s):  
Laura E. Richardson ◽  
Nicholas A. J. Graham ◽  
Andrew S. Hoey

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.


2019 ◽  
Vol 286 (1897) ◽  
pp. 20182672 ◽  
Author(s):  
Alexandre C. Siqueira ◽  
David R. Bellwood ◽  
Peter F. Cowman

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.


2020 ◽  
Author(s):  
V Parravicini ◽  
MG Bender ◽  
S Villéger ◽  
F Leprieur ◽  
L Pellissier ◽  
...  

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.


2020 ◽  
Vol 649 ◽  
pp. 125-140
Author(s):  
DS Goldsworthy ◽  
BJ Saunders ◽  
JRC Parker ◽  
ES Harvey

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.


2021 ◽  
Author(s):  
Cher F Y Chow ◽  
Caitlin Bolton ◽  
Nader Boutros ◽  
Viviana Brambilla ◽  
Luisa Fontoura ◽  
...  

The process of coral recruitment is crucial to the healthy functioning of coral reef ecosystems, as well as recovery following disturbances. Fishes are key modulators of this process by feeding on algae and other benthic taxa that compete with corals for benthic space. However, foraging strategies within reef fish assemblages are highly diverse and the effect of foraging diversity on coral recruitment success remains poorly understood. Here, we test how the foraging traits of reef fishes affect coral settlement and juvenile success at Lizard Island, Great Barrier Reef. Using a multi-model inference approach incorporating six metrics of fish assemblage foraging diversity (foraging rates, trait richness, trait evenness, trait divergence, herbivore abundance, and benthic invertivore abundance), we found that herbivore abundance had positive effects on both coral settlement and recruitment success. However, foraging trait diversity had a negative effect on coral settlement but not on recruitment. Coral settlement was higher at sites with less trait diverse fish assemblages, specifically in trait divergence and richness. Moreover, these two trait diversity metrics were stronger predictors of coral settlement success compared to herbivore abundance. Our findings provide evidence that impacts mediated by fish foraging on coral juveniles can potentially be harmful during settlement, but the space-clearing effect overall remains advantageous. We show here that the variation of fish biodiversity across reefs can be a partial driver to spatially uneven patterns of coral recruitment and reef recovery.


2020 ◽  
Vol 3 (1) ◽  
pp. 6
Author(s):  
Nidzar Muhammad Rafly ◽  
I Wayan Gede Astawa Karang ◽  
Widiastuti Widiastuti

Reef fishes are the highest number of organisms that can be found in coral reefs in which the abundance depends on the healthy of this ecosystem. Reef fishes are mainly consisted of corallivorous and herbivorous fish. Corralivorous fish feeds on coral polyps while herbivorous fish feeds on algae. Therefore these fishes are an important indicators in the resilience of coral reefs. Studies showed that its abundance is strongly correlated with reef’s conture (rugosity). Pemuteran waters is one of developing tourists attraction in the north Bali island. However, the data of reef fishes and coral reefs in Pemuteran waters remain limited. Therefore, this research aimed to study the reef` condition and rugosity in Pemuteran waters, also to examine the correlation between reefs fishes and reefs rugosity in this area. There were four stations according to purposive sampling method. Data of corallivorous and herbivorous fishes were collected by using the underwater visual census with a 40 m2 transect. Reef rugosity index were determined by using chain transect method. Results showed that reef rugosity in Pemuteran waters was in the medium to high category. Reef rugosity has strong correlation with the total abundance and diversity of corallivorous fishes. However, reef rugosity was only strong correlated with the total abundance but not with the diversity of herbivorous fishes.


Author(s):  
Charles Sheppard

Healthy reefs provide a habitat for an immense number of fish that come in a variety of shapes, sizes, and colours. No other natural habitat in the ocean shows this diversity and abundance. About a quarter of all marine species may be found on coral reefs even though this habitat occupies only one or two per cent of the area of the earth. ‘Reef fish and other major predators’ describes the diverse feeding ecology of reef fishes; coral reef predators such as the colourful crown of thorns starfish, Acanthaster plancii; symbiotic relationships between different species of fish or with different invertebrates; and the dangers of overfishing in reef communities.


2016 ◽  
Vol 67 (5) ◽  
pp. 605 ◽  
Author(s):  
Amy G. Coppock ◽  
Naomi M. Gardiner ◽  
Geoffrey P. Jones

Coral degradation is a major threat towards the biodiversity of coral-reef ecosystems, either through the physical effects of environmental change, or biological agents such as crown-of-thorns (Acanthaster planci). Coral loss is leading to significant declines in reef-fish assemblages, particularly those dependent on live coral as settlement sites. Most reef fishes use olfactory stimuli at settlement; however, their ability to detect chemical stimuli from degraded corals or A. planci is unknown. Here, olfactory responses of juvenile reef fishes to the presence of stressed corals and A. planci were tested. Juveniles of eight common coral-associated species were subjected to a series of pair-wise choice tests, where the period of time spent in two differing water sources was noted. All species demonstrated a significant attraction towards healthy coral (≥76%), avoiding cues emitted by stressed coral colonies. When given the choice between a control water (untreated reef water) and water containing chemical cues from A. planci, most species elicited no response. Finally, when given the choice between chemical cues derived from feeding A. planci or the control, all species avoided A. planci (≥70%). Our results indicated that juvenile reef fish are capable of distinguishing the state of coral health, but not directly from disturbance agents.


2008 ◽  
Vol 35 (3) ◽  
pp. 261-272 ◽  
Author(s):  
I. D. WILLIAMS ◽  
W. J. WALSH ◽  
R. E. SCHROEDER ◽  
A. M. FRIEDLANDER ◽  
B. L. RICHARDS ◽  
...  

SUMMARYHumans can impact coral reef fishes directly by fishing, or indirectly through anthropogenic degradation of habitat. Uncertainty about the relative importance of those can make it difficult to develop and build consensus for appropriate remedial management. Relationships between fish assemblages and human population density were assessed using data from 18 locations widely spread throughout the Main Hawaiian Islands (MHI) to evaluate the significance of fishing as a factor potentially driving fish trends on a regional scale. Fish biomass in several groups was negatively correlated with local human population density and a number of lines of evidence indicate that fishing was the prime driver of those trends. First, declines were consistently evident among fish groups targeted by fishers, but not among lightly fished or non-target groupings, which indicates that declines in target groups were not simply indicative of a general decline in habitat quality along human population gradients. Second, proximity to high human populations was not associated with low fish biomass where shoreline structure prevented ready access by fishers. Relatively remote and inaccessible locations within the MHI had 2.1–4.2 times the biomass of target fishes compared to accessible and populous locations, and may therefore function as partial refugia. However, stocks in those areas were clearly far from pristine, as biomass of large predators was more than an order of magnitude lower than at more intact ecosystems elsewhere in the Pacific.


Sign in / Sign up

Export Citation Format

Share Document