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51.
Tropical herbivores provide resilience to a climate‐mediated phase shift on temperate reefs 下载免费PDF全文
Scott Bennett Thomas Wernberg Euan S. Harvey Julia Santana‐Garcon Benjamin J. Saunders 《Ecology letters》2015,18(7):714-723
Climate‐mediated changes to biotic interactions have the potential to fundamentally alter global ecosystems. However, the capacity for novel interactions to drive or maintain transitions in ecosystem states remains unresolved. We examined temperate reefs that recently underwent complete seaweed canopy loss and tested whether a concurrent increase in tropical herbivores could be maintaining the current canopy‐free state. Turf‐grazing herbivorous fishes increased in biomass and diversity, and displayed feeding rates comparable to global coral reefs. Canopy‐browsing herbivores displayed high (~ 10 000 g 100 m?2) and stable biomass between 2006 and 2013. Tropical browsers had the highest abundance in 2013 and displayed feeding rates approximately three times higher than previously observed on coral reefs. These observations suggest that tropical herbivores are maintaining previously kelp‐dominated temperate reefs in an alternate canopy‐free state by grazing turfs and preventing kelp reestablishment. This remarkable ecosystem highlights the sensitivity of biotic interactions and ecosystem stability to warming and extreme disturbance events. 相似文献
52.
The present study aimed to investigate the spatial structure of fish communities at juvenile and adult stages on coral reefs
at Kudaka Island (Ryukyu Archipelago, Japan) and to relate spatial patterns in the structure of the fish communities to gradients
in environmental variables. Diurnal visual censuses allowed us to record 2,602 juveniles belonging to 60 species and 1,543
adults belonging to 53 species from October to December 2005. The distribution of species highlighted that the juvenile community
was organised into three distinct assemblages, rather than exhibiting gradual change in community structure along the cross-reef
gradient. Correlations between spatial patterns of juvenile community and environmental variables revealed that the most significant
factors explaining variation in community structure were coral rubble and coral slab. In contrast, the adult community was
organised into one assemblage, and the most significant variation factors in community structure were depth, live coral in
massive form, live coral in branched form, dead coral and sand. Overall, the present study showed that most juvenile and adult
coral reef fish at Kudaka Island exhibited striking patterns in their distribution and depth and some biological factors (e.g.,
abundance of live coral, dead coral and coral rubble) might exert considerable influence on the distribution of fishes. 相似文献
53.
84 quadrats from 5 vertical transects of Luhuitou fringing reef are investigated in detail by using video-quadrat and indoor-interpretation methods. The results show that (1) the reef consists of 69 species of hermatypic corals belonging to 24 genera and 13 families which are unevenly distributed in abundance. (2) Among all the corals, Porites lutea is the most dominant species with importance value percentage up to 36.62%; Porites and Acropora are dominant genera with importance value percentages 43.85% and 22.88%, respectively. (3) There exist distinct spatial differences in coral communities. Both the coral covers and coral diversity indices on the northeastern transects are higher than those on the central and southern transects. (4) Coral communities also show remarkable zonal characteristics with less coral species occurring on reef flat than on reef slope. The importance value percentage of the sole dominant coral genus, Porites, is over 50%, while on the reef slope, the importance value percentages are 28.33% for the first dominant genus Acropora and 26.71% for the second dominant genus Porites. Our further analysis suggests that the spatial and zonal differences of coral diversity pattern are correlated with both natural environmental changes and human activities. The shallow water reef flat is frequently exposed at low tide and it receives more anthropogenic influences (including dredging and trampling) than the deep water reef slope. Thus, the coral community on the reef flat is not as well developed as that on reef slope. The relatively poor coral covers and coral diversity indices on the central and southern transects are closely related to heavy human activities around these sites such as aquaculture, fishing and coastal sewage drainage. Therefore, the impact of human activities must be taken into account in developing strategies for the protection of this coral reef. 相似文献
54.
The Brazilian coast, the Caribbean and the tropical South Atlantic oceanic islands reef ichthyofauna separated into two major clusters: (1) the western Atlantic continental margin and Bermuda, further divided into (1a) the western North Atlantic, and (1b) the Brazilian coast; and (2) the South Atlantic oceanic islands, also divided in (2a) the Brazilian offshore islands, and (2b) Ascension and St Helena. Species geographic ranges suggest the recognition of only two western Atlantic zoogeographic provinces for tropical marine shore fishes. A Brazilian Province, including the offshore localities of Atol das Rocas, Fernando de Noronha, Trindade and St Paul's Rocks, and an expanded West Indian Province that includes Bermuda. Ascension and St Helena should be regarded as a separated Central Atlantic Province. 相似文献
55.
GÖRAN E. NILSSON NATALIE CRAWLEY†‡ IDA G. LUNDE PHILIP L. MUNDAY†‡ 《Global Change Biology》2009,15(6):1405-1412
The capacity for marine fishes to perform aerobically (aerobic scope) is predicted to control their thermal tolerance and, thus, the impact that rapid climate change will have on their populations. We tested the effect of increased water temperatures on the resting and maximum rates of oxygen consumption in five common coral reef fishes at Lizard Island on the northern Great Barrier Reef, Australia. All species exhibited a decline in aerobic capacity at elevated water temperatures (31, 32 or 33 °C) compared with controls (29 °C); however, the response was much stronger in two cardinalfishes, Ostorhinchus cyanosoma and O. doederleini , compared with three damselfishes, Dascyllus anuarus, Chromis atripectoralis and Acanthochromis polyacanthus . Aerobic scope of the two cardinalfishes was reduced by nearly half at 31 °C compared with 29 °C, and virtually all capacity for additional oxygen uptake was exhausted by 33 °C. In contrast, the three damselfishes retained over half their aerobic scope at 33 °C. Such differences in thermal tolerance between species, and possibly families, suggest that the community structure of reef fish assemblages might change significantly as ocean temperatures increase. Populations of thermally tolerant species are likely to persist at higher temperatures, but populations of thermally sensitive species could decline on low-latitude reefs if individual performance falls below levels needed to sustain viable populations. 相似文献
56.
Jameal F. Samhouri Richard R. Vance Graham E. Forrester Mark A. Steele 《Oecologia》2009,160(2):257-265
Structural refuges within which prey can escape from predators can be an important limiting resource for the prey. In a manner
that resembles the childhood game of musical chairs, many prey species rapidly retreat to shared, unguarded refuges whenever
a predator threatens, and only when refuges are relatively abundant do all prey individuals actually escape. The key feature
of this process is that the per capita prey mortality rate depends on the ratio of prey individuals to refuges. We introduce
a new class of mortality functions with this feature and then demonstrate statistically that they describe field mortality
data from a well-studied coral reef fish species, the Caribbean bridled goby Coryphopterus glaucofraenum, substantially better than do several mortality functions of more conventional form.
J. F. Samhouri and R. R. Vance contributed equally to this work. 相似文献
57.
Algal contact as a trigger for coral disease 总被引:4,自引:0,他引:4
Maggy M. Nugues Garriet W. Smith Ruben J. van Hooidonk Maria I. Seabra Rolf P. M. Bak 《Ecology letters》2004,7(10):919-923
Diseases are causing alarming declines in reef‐building coral species, the foundation blocks of coral reefs. The emergence of these diseases has occurred simultaneously with large increases in the abundance of benthic macroalgae. Here, we show that physical contact with the macroalga Halimeda opuntia can trigger a virulent disease known as white plague type II that has caused widespread mortality in most Caribbean coral species. Colonies of the dominant coral Montastraea faveolata exposed to algal transplants developed the disease whereas unexposed colonies did not. The bacterium Aurantimonas coralicida, causative agent of the disease, was present on H. opuntia sampled close to, and away from diseased corals, indicating that the alga serves as a reservoir for this pathogen. Our results suggest that the spread of macroalgae on coral reefs could account for the elevated incidence of coral diseases over past decades and that reduction of macroalgal abundance could help control coral epizootics. 相似文献
58.
59.
The cellular condition of liver hepatocytes and the height of gut epithelium cells of larval Amphiprion melanopus were sensitive indicators of feeding condition. Muscle fibres of the trunk showed marked separation in fish fed every third day just prior to settlement. Low feeding regimes also caused reductions in growth, increases in larval duration and reductions in size at metamorphosis. Gut epithelium cell height was also influenced by fish standard length and age. This study suggests that gut epithelium cell height is a useful index for an examination of the importance of starvation of larvae in tropical waters; however, size and age standardization is required prior to comparisons of wild caught fish through time or with laboratory samples. 相似文献
60.
Denise P. Silva Gustavo Duarte Helena D.M. Villela Henrique F. Santos Phillipe M. Rosado Joo Gabriel Rosado Alexandre S. Rosado Edir M. Ferreira Adriana U. Soriano Raquel S. Peixoto 《Ecology and evolution》2019,9(9):5172-5185
Although numerous studies have been carried out on the impacts of oil spills on coral physiology, most have relied on laboratory assays. This scarcity is partly explained by the difficulty of reproducing realistic conditions in a laboratory setting or of performing experiments with toxic compounds in the field. Mesocosm systems provide the opportunity to carry out such studies with safe handling of contaminants while reproducing natural conditions required by living organisms. The mesocosm design is crucial and can lead to the development of innovative technologies to mitigate environmental impacts. Therefore, this study aimed to develop a mesocosm system for studies simulating oil spills with several key advantages, including true replication and the use of gravity to control flow‐through that reduces reliance on pumps that can clog thereby decreasing errors and costs. This adaptable system can be configured to (a) have continuous flow‐through; (b) operate as an open or closed system; (c) be fed by gravity; (d) have separate mesocosm sections that can be used for individual and simultaneous experiments; and (e) simulate the migration of oil from ocean oil spills to the nearby reefs. The mesocosm performance was assessed with two experiments using the hydrocoral Millepora alcicornis and different configurations to simulate two magnitudes of oil spills. With few exceptions, physical and chemical parameters remained stable within replicates and within treatments throughout the experiments. Physical and chemical parameters that expressed change during the experiment were still within the range of natural conditions observed in Brazilian marine environments. The photosynthetic potential (Fv/Fm) of the algae associated with M. alcicornis decreased in response to an 1% crude‐oil contamination, suggesting a successful delivery of the toxic contaminant to the targeted replicates. This mesocosm is customizable and adjustable for several types of experiments and proved to be effective for studies of oil spills. 相似文献