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

2016 ◽  
Vol 283 (1844) ◽  
pp. 20160128 ◽  
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.

Endoparasite species richness of New Caledonian butterfly fishes: host density and diet matter

Parasitology ◽  
2000 ◽  
Vol 121 (1) ◽  
pp. 65-73 ◽  
Author(s):  
S. MORAND ◽  
T. H. CRIBB ◽  
M. KULBICKI ◽  
M. C. RIGBY ◽  
C. CHAUVET ◽  
...  
Keyword(s):  
Species Richness ◽  
Coral Reef ◽  
Parasite Species ◽  
New Caledonia ◽  
Ecological Factors ◽  
Host Density ◽  
Reef Fishes ◽  
Coral Reef Fishes ◽  
Ancestral State ◽  
Parasite Species Richness

Ecological factors may influence the number of parasites encountered and, thus, parasite species richness. These factors include diet, gregarity, conspecific and total host density, habitat, body size, vagility, and migration. One means of examining the influence of these factors on parasite species richness is through a comparative analysis of the parasites of different, but related, host species. In contrast to most comparative studies of parasite species richness of fish, which have been conducted by using data from the literature, the present study uses data obtained by the investigators. Coral reef fishes vary widely in the above ecological factors and are frequently parasitized by a diverse array of parasites. We, therefore, chose to investigate how the above ecological factors influence parasite species richness in coral reef fishes. We investigated the endoparasite species richness of 21 species of butterfly fishes (Chaetodontidae) of New Caledonia. We mapped the diet characters on the existing butterfly fish phylogeny and found that omnivory appears to be ancestral. We also mapped the estimated endoparasite species richness, coded from low to high parasite species richness, on the existing butterfly fish phylogeny and found that low parasite species richness appears to be associated with the ancestral state of omnivory. Different dietary and social strategies appear to have evolved more than once, with the exception of obligate coralivory, which appears to have evolved only once. Finally, after controlling for phylogenetic relationships, we found that only the percentage of plankton in the diet and conspecific host density were positively correlated with endoparasite species richness.

scholarly journals Coral species composition drives key ecosystem function on coral reefs

2020 ◽  
Vol 287 (1921) ◽  
pp. 20192214 ◽  
Author(s):  
Laura E. Richardson ◽  
Nicholas A. J. Graham ◽  
Andrew S. Hoey
Keyword(s):  
Coral Reefs ◽  
Species Composition ◽  
Coral Species ◽  
Fish Assemblages ◽  
Reef Fishes ◽  
Ecosystem Functions ◽  
Algal Turf ◽  
Benthic Assemblages ◽  
Ecosystem Recovery ◽  
Visual Occlusion

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.

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

2019 ◽  
Vol 286 (1897) ◽  
pp. 20182672 ◽  
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.

Spirocamallanus species of French Polynesian coral reef fishes

1997 ◽  
Vol 75 (8) ◽  
pp. 1270-1279 ◽  
Author(s):  
Mark C. Rigby ◽  
Martin L. Adamson
Keyword(s):  
Coral Reef ◽  
Ecological Factors ◽  
Buccal Capsule ◽  
Reef Fishes ◽  
French Polynesia ◽  
New Host ◽  
Society Islands ◽  
Single Clade ◽  
Taxonomic Importance ◽  
New Host Records

Spirocamallanus monotaxis is redescribed from Monotaxis grandoculis (Lethrinidae) and reported from 10 other species of coral reef associated fishes from both the Society Islands and the Tuamotu Islands. This represents a new locality for S. monotaxis and 10 new host records. Spirocamallanus colei n.sp. is described from Acanthurus achilles (Acanthuridae) and from Acanthurus guttatus, Acanthurus lineatus, Acanthurus triostegus, and Zebrasoma scopas from both the Society Islands and the Tuamotu Islands. Spirocamallanus chaimha n.sp. is described from Ctenochaetus striatus and Acanthurus olivaceous (Acanthuridae) from Moorea in the Society Islands. The number of buccal capsule ridges in Spirocamallanus varies and minor differences have no taxonomic importance. Marine Spirocamallanus species appear to belong to a single clade characterized by 3 preanal papillae and 5 postanal papillae. This clade may be subdivided on the basis of the shape of the female tail. In French Polynesia, ecological factors as opposed to phylogenetic factors appear to determine host specificity for Spirocamallanus. A new system of reporting the positions of the caudal papillae, based on the position of the papillae relative to the length of the alae, is used.

scholarly journals Olfactory responses of coral-reef fishes to coral degradation and crown-of-thorns (Acanthaster planci)

2016 ◽  
Vol 67 (5) ◽  
pp. 605 ◽  
Author(s):  
Amy G. Coppock ◽  
Naomi M. Gardiner ◽  
Geoffrey P. Jones
Keyword(s):  
Coral Reef ◽  
Reef Fish ◽  
Chemical Cues ◽  
Fish Assemblages ◽  
Reef Fishes ◽  
Live Coral ◽  
Acanthaster Planci ◽  
Olfactory Responses ◽  
Olfactory Stimuli ◽  
Coral Reef Ecosystems

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.

Assessing the importance of fishing impacts on Hawaiian coral reef fish assemblages along regional-scale human population gradients

2008 ◽  
Vol 35 (3) ◽  
pp. 261-272 ◽  
Author(s):  
I. D. WILLIAMS ◽  
W. J. WALSH ◽  
R. E. SCHROEDER ◽  
A. M. FRIEDLANDER ◽  
B. L. RICHARDS ◽  
...  
Keyword(s):  
Coral Reef ◽  
Population Density ◽  
Human Population ◽  
Fish Assemblages ◽  
Regional Scale ◽  
Reef Fishes ◽  
Human Populations ◽  
Fish Biomass ◽  
Human Population Density ◽  
General Decline

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.

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