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1.
珊瑚礁生态系统是一个高生产力、高生物多样性的特殊海洋生态系统,具有为生物提供栖息地、参与生物地球化学循环、防浪护岸、指示水体污染程度等生态功能。珊瑚礁生态系统的突出特点是其生境异质性很高,各种各样的生境斑块为种类繁多、习性各异的游泳和底栖生物提供栖息场所,这些礁栖生物通过参与各项生态过程而形成各种特定的功能群,共同完成重要的生态功能。在热带珊瑚礁生态系统中,海参是大型底栖动物区系的重要一员。种类繁多的海参具有各自不同的生境选择特征,通过摄食、运动等行为活动发挥着改良底质、促进有机物矿化和营养盐再生等生态作用。近几年来,全球热带海参受人类过度捕捞和珊瑚礁退化的影响而面临资源衰退、物种多样性丧失等问题,深入认识其生态学功能、加强热带海参资源保护迫在眉睫。综述了国内外热带珊瑚礁海参的基础生态学研究进展:海参对珊瑚礁生境斑块呈现显著的偏好选择特征以及种间差异和季节变动,不同生境斑块的食物质量、底质类型和水动力条件是影响海参生境偏好的重要因素;海参通过生物扰动可以改变珊瑚礁生境沉积物的含水量、渗透性、颗粒组成、再矿化率、无机营养物质释放速率以及孔隙水的化学梯度,并增加沉积物中的溶氧浓度、促进溶解... 相似文献
2.
Evolutionary history of the parrotfishes: biogeography,ecomorphology, and comparative diversity 总被引:15,自引:0,他引:15
Streelman JT Alfaro M Westneat MW Bellwood DR Karl SA 《Evolution; international journal of organic evolution》2002,56(5):961-971
The family Scaridae comprises about 90 species of herbivorous coral reef, rock reef, and seagrass fishes. Parrotfishes are important agents of marine bioerosion who rework the substrate with their beaklike oral jaws. Many scarid populations are characterized by complex social systems including highly differentiated sexual stages, territoriality, and the defense of harems. Here, we test a hypothesis of relationships among parrotfish genera derived from nearly 2 kb of nuclear and mitochondrial DNA sequence. The DNA tree is different than a phylogeny based on comparative morphology and leads to important reinterpretations of scarid evolution. The molecular data suggest a split among seagrass and coral reef associated genera with nearly 80% of all species in the coral reef clade. Our phylogenetic results imply an East Tethyan origin of the family and the recurrent evolution of excavating and scraping feeding modes. It is likely that ecomorphological differences played a significant role in the initial divergence of major scarid lineages, but that variation in color and breeding behavior has triggered subsequent diversification. We present a two-phase model of parrotfish evolution to explain patterns of comparative diversity. Finally, we discuss the application of this model to other adaptively radiating clades. 相似文献
3.
Representative coral reef organisms and substrata assembled in a laboratory microcosm removed radioactively labelled bacteria from water circulated over them. A similar experiment with a reef clam and its algal-encrusted base gave similar results. Biochemical fractionation of selected organisms in these experiments suggested digestion and possible assimilation of bacterial proteins. In view of previous results concerning the microbial ecology of coral reefs, it is suggested that reef infaunal metazoa are adapted to utilize internal sedimentary processes and regenerative functioning through suspension- (and deposit-)feeding mechanisms. A model ecosystem is presented to suggest the possible feedback of these mechanisms as they operate within a reef. 相似文献
4.
珊瑚礁区碳循环研究进展 总被引:5,自引:0,他引:5
珊瑚礁是海洋中生产力水平最高的生态系统之一,其碳循环受到有机碳代谢(光合作用/呼吸作用)和无机碳代谢(钙化/溶解)两大代谢过程的共同作用,过程十分复杂.珊瑚礁植物的光合作用保证了有机碳的有效补充,动物摄食及微生物降解等生物过程驱动了珊瑚礁区有机碳高效循环,只有不超过7%的有机碳进入沉积物,而向大洋区水平输出的有机碳通量变化幅度较大,主要受到水动力条件的影响.珊瑚礁区碳酸盐沉积(无机碳代谢)是全球碳酸盐库的重要组成部分,年累积量达到全球CaCO3年累积量的23%~26%,是影响大气CO2浓度的重要组成;珊瑚礁是大气CO2源或汇则取决于净有机生产力与净无机生产力的比值(ROI),当ROI <0.6时,珊瑚礁区是大气CO2的源,反之,则是大气CO2的汇. 相似文献
5.
珊瑚藻是海洋红藻中的大型钙化藻类,全球分布623种,中国现有记录共77种。随着生态科学研究的广泛展开,人们越来越认识到,珊瑚藻在海洋生态系统中,尤其在维持珊瑚礁生态系统的生物多样性及生态功能中发挥着重要作用。目前,科研人员对有关珊瑚藻的初级生产力、钙化作用以及在诱导底栖无脊椎动物幼虫的附着与变态等方面已有多方面的研究和探索。然而,有关珊瑚藻生态功能的深层次机理问题有待进一步深入研究。文章着重围绕目前珊瑚藻研究中的一些热点问题,从近年来珊瑚藻在珊瑚礁生态系统中的生态功能方面的研究概况进行综述,以期加深人们对珊瑚藻的认识,并促进对珊瑚藻生态功能的进一步深入研究。 相似文献
6.
Thomas J. Near Peter. C. Wainwright 《Evolution; international journal of organic evolution》2013,67(2):417-428
The relationship between habitat complexity and species richness is well established but comparatively little is known about the evolution of morphological diversity in complex habitats. Reefs are structurally complex, highly productive shallow‐water marine ecosystems found in tropical (coral reefs) and temperate zones (rocky reefs) that harbor exceptional levels of biodiversity. We investigated whether reef habitats promote the evolution of morphological diversity in the feeding and locomotion systems of grunts (Haemulidae), a group of predominantly nocturnal fishes that live on both temperate and tropical reefs. Using phylogenetic comparative methods and statistical analyses that take into account uncertainty in phylogeny and the evolutionary history of reef living, we demonstrate that rates of morphological evolution are faster in reef‐dwelling haemulids. The magnitude of this effect depends on the type of trait; on average, traits involved in the functional systems for prey capture and processing evolve twice as fast on reefs as locomotor traits. This result, along with the observation that haemulids do not exploit unique feeding niches on reefs, suggests that fine‐scale trophic niche partitioning and character displacement may be driving higher rates of morphological evolution. Whatever the cause, there is growing evidence that reef habitats stimulate morphological and functional diversification in teleost fishes. 相似文献
7.
Summary The Upper Rhaetian coral limestone of Adnet, southeast of Salzburg Austria has been repeatedly referred to as one of the most
spectacular examples of an ancient ‘autochthonous’ coral reef structure. The ‘Tropfbruch’ quarry is probably the best outcrop
for interpreting the distributional patterns of biotic successions and communities of a late Triassic patch reef. Our study
is based on the interpretation of a) outcrop photographs, b) reef maps resulting from quadrat transects, and c) the analysis
of quantitative data describing the distribution and frequency of reef organisms and sediment. A new methodological approach
(combination of reef mapping and photo-transects) is used to obtain quantitative field data which can be compared in greater
detail with data from modern coral reefs investigated by corresponding quantitative surveys.
Three unconformities and three well-defined ‘reef growth stages’ reflecting the vertical and lateral development of the reef
structure were differrentiated using transects:
Stage 1, representing the reef growth optimum, is characterized by laterally differentiated coral reef knobs with corals in
growth position. Criteria supporting this interpretation are the extraordinary size of the corals, their preservation in situ
and the great thickness of this interval. The massive coralPamiroseris grew under higher energy conditions at the rim of the reef knob, whereas branchingRetiophyllia colonies preferred less agitated water in the center. Vertical changes are reflected by an increase in frequency of the dasycladacean
algaDiplopora adnetensis and by the decreasing size ofRetiophyllia. These sedimentological and biological criteria together with the unconformity above indicate a fall in the sea level as
a major control mechanism.
Stage 2, separated from stage 1 by an unconformity caused by partial subaerial exposure and karstification, is characterized
by vertically stacked coral successions with diverse reef debris. Facies heterogeneity is reflected by differences in the
diversity, taphonomy and packing density of reef-building organisms as well as by differences in sediment input from the platform.
Water depths and accommodation space were lower, therefore minor sea level fluctuations had a stronger effect on the biotic
composition. The high percentage of coral debris and corals reworked by storms and the increase in the input of platform sediment
led to a reduction of reef growth.
Stage 3, again separated at the base by an unconformity associated with karstification, is characterized by bioclastic sediments
with isolated reefbuilders forming a level-bottom community. The distribution of different coral morphotypes suggests that
sea level fluctuations were not the only controlling factor. Variations in the substrate were caused by differences in the
input of platform sediment.
The three-step development seen in Adnet documents the response of low-diverse coral associations to variations caused by
small-scale sea level changes, storm activity and sedimentation. The vertical changes in reef community structures correspond
to a sequence of ‘allogenic replacements’.
The Adnet reef structure should not be regarded as a general model of Alpine Upper Rhaetian reefs, because of the particular
setting of the patch reef. Only the ‘capping beds’ of the Upper Rhaetian Reef Limestone of the Steinplatte exhibit criteria
similar to Adnet.
Potential modern analogues of features seen in the coral communities of Adnet are the internal structure of theRetiophyllia thickets, the key role of branching corals within the communities, the scattered distribution and low and even diversity
of corals subsequent to breaks in settlement, segration patterns of corals indicating ‘contact avoidance’, toppling of large
coral colonies by intensive boring, and decreasing coral coverage from deeper and sheltered settings to more shallower water
depths. 相似文献
8.
J. Mallela 《Coral reefs (Online)》2007,26(4):775-785
Encrusting calcareous organisms such as bryozoans, crustose coralline algae (CCA), foraminiferans, and serpulid worms are
integral components of tropical framework-building reefs. They can contribute calcium carbonate to the reef framework, stabilise
the substrate, and promote larval recruitment of other framework-building species (e.g. coral recruits). The percentage cover
of encrusting organisms and their rates of carbonate production (g m−2 year−1) were assessed at four sites within a coastal embayment, along a gradient of riverine influence (high-low). As the orientation
and type of substrate is thought to influence recruitment of encrusting organisms, organisms recruiting to both natural (the
underside of platy corals) and experimental substrates were assessed. The effect of substrate exposure under different levels
of riverine influence was assessed by orientating experimental substrates to mimic cryptic and exposed reef habitats (downwards-facing
vs upwards-facing tiles) at each site. Cryptic experimental tiles supported similar encruster assemblages to those recruiting
to the underneath (cryptic side) of platy corals, suggesting that tiles can be used as an experimental substrate to assess
encruster recruitment in reef systems. Encruster cover, in particular CCA, and carbonate production was significantly higher
at low-impact (clear water), high wave energy sites when compared to highly riverine impacted (turbid water), low wave energy
sites. Cryptically orientated substrates supported a greater diversity of encrusting organisms, in particular serpulid worms
and bryozoans. The inverse relationships observed between riverine inputs and encrusters (total encruster cover and carbonate
production) have implications for both the current and future rates and styles of reefal framework production. 相似文献
9.
病毒对珊瑚礁生态系统中的生物进化、生物地球化学循环、珊瑚疾病等方面具有重要的生态影响。随着珊瑚礁的全球性退化,病毒在珊瑚礁生态系统中的功能与危害日益显现。综述了珊瑚礁生态系统中病毒的研究现状与进展,包括:(1)珊瑚礁病毒的多样性与分布特征(水体、宿主、核心病毒组);(2)珊瑚礁病毒的生态功能(感染方式、促进生物进化、生物地球化学循环);(3)珊瑚礁病毒对全球气候变化的响应(热压力、珊瑚疾病)。总体而言,珊瑚礁生态系统具有极高的病毒多样性,所发现的60个科占已知所有病毒科数量的58%。珊瑚的核心病毒组主要由双链DNA病毒、单链DNA病毒、单链逆转录病毒所组成,珊瑚黏液层对病毒具有富集作用。"Piggyback-the-Winner"(依附-胜利)是病毒在珊瑚礁中主要的生物动力学模式,其可通过水平基因迁移的方式促进礁区生物进化。病毒可通过裂解细菌与浮游藻类的途径参与珊瑚礁的生物地球化学循环,尤其是碳循环与氮循环过程。此外,病毒还具有介导珊瑚热白化与直接引发珊瑚疾病的能力,这会影响珊瑚礁生态系统应对气候变化的适应性与恢复力。基于国际上的研究进展综述,结合南海珊瑚礁生态现状提出以下研究方向,以期促进我国珊瑚礁病毒学的发展:(1)开展南海珊瑚礁中病毒多样性的识别及其时-空分布特征研究;(2)探索病毒对南海珊瑚热白化、珊瑚疾病的介导作用及其与气候变化的关系;(3)揭示病毒对南海珊瑚礁生物地球化学循环的贡献。 相似文献
10.
《Biological reviews of the Cambridge Philosophical Society》2018,93(2):1192-1202
Hydra is emerging as a model organism for studies of ageing in early metazoan animals, but reef corals offer an equally ancient evolutionary perspective as well as several advantages, not least being the hard exoskeleton which provides a rich fossil record as well as a record of growth and means of ageing of individual coral polyps. Reef corals are also widely regarded as potentially immortal at the level of the asexual lineage and are assumed not to undergo an intrinsic ageing process. However, putative molecular indicators of ageing have recently been detected in reef corals. While many of the large massive coral species attain considerable ages (>600 years) there are other much shorter‐lived species where older members of some populations show catastrophic mortality, compared to juveniles, under environmental stress. Other studies suggestive of ageing include those demonstrating decreased reproduction, increased susceptibility to oxidative stress and disease, reduced regeneration potential and declining growth rate in mature colonies. This review aims to promote interest and research in reef coral ageing, both as a useful model for the early evolution of ageing and as a factor in studies of ecological impacts on reef systems in light of the enhanced effects of environmental stress on ageing in other organisms. 相似文献
11.
Orientation behavior of butterflyfishes (family Chaetodontidae) on coral reefs: spatial learning of route specific landmarks and cognitive maps 总被引:2,自引:0,他引:2
Ernst S. Reese 《Environmental Biology of Fishes》1989,25(1-3):79-86
Synopsis Foraging butterflyfishes follow predictable paths as they swim from one food patch to another within their territories and
home ranges. The pattern is repeated throughout the day. The behavior is described in species belonging to the coral feeding
guild. Habit formation and spatial learning are implicated. Foraging paths are based on learned locations of route specific
landmarks. When a coral head is removed the fish look for it in its former location. If pairs of foraging fish are deflected
from the path, they resume their routine pattern at the first landmark they encounter. Periodically, fish make excursions
of 30 m or more to distant parts of the reef. Usually they follow different paths on the outbound and homeward legs of these
excursions. The critical question is: Are the paths novel? If they are, it is evidence for the use of cognitive maps. Certainly
fishes living in the highly structured coral reef environment are prime candidates to use cognitive maps in their orientation
behavior. 相似文献
12.
N. A. J. Graham S. K. Wilson M. S. Pratchett N. V. C. Polunin M. D. Spalding 《Biodiversity and Conservation》2009,18(12):3325-3336
As climate change increasingly threatens biodiversity, identifying specific drivers of species loss as well as the attributes
of species most vulnerable to climatic disturbances is a key challenge to ecologists and conservationists. Here we assess
the effects of coral loss versus declines in structural complexity on obligate and facultative coral feeding butterflyfishes
on coral reefs in the central and western Indian Ocean. In the inner Seychelles, the abundance of the obligate coral feeding
group declined markedly in response to live coral mortality (r
2 = 0.48), but showed no further decline with respect to erosion of the physical matrix of the reef. Conversely, the facultative
feeding group showed no decline in response to live coral loss, reflecting their feeding versatility; however they did decline
in response to structural erosion of the reef framework (r
2 = 0.26). There were no significant changes in either obligate or facultative corallivore abundances at a reference location
(Chagos archipelago), highlighting that butterflyfish populations are stable in the absence of habitat disturbance. While
specialised coral dependant fishes are highly vulnerable to coral loss caused by climate-induced coral bleaching, the structural
collapse of dead coral colonies may have significant, but more variable, impacts across a wide range of fishes. If conservation
and mitigation planning are to be effective, there is a clear need to better understand the mechanisms of reef structural
collapse and the dynamics of system recovery following large-scale disturbance. 相似文献
13.
This study compared remote underwater video and traditional direct diver observations to assess reef fish feeding impact on benthos across multiple functional groups within different trophic categories (e.g. herbivores, zoobenthivores and omnivores) and in two distinct reef systems: a subtropical rocky reef and a tropical coral reef. The two techniques were roughly equivalent, both detecting the species with higher feeding impact and recording similar bite rates, suggesting that reef fish feeding behaviour at the study areas are not strongly affected by the diver's presence. 相似文献
14.
Expanding networks: Signaling components in and a hypothesis for the evolution of metamorphosis 总被引:1,自引:0,他引:1
Hodin J 《Integrative and comparative biology》2006,46(6):719-742
Metamorphosis is a substantial morphological transition between2 multicellular phases in an organism's life cycle, often markingthe passage from a prereproductive to a reproductive life stage.It generally involves major physiological changes and a shiftin habitat and feeding mode, and can be subdivided into an extendedphase of substantial morphological change and/or remodeling,and a shorter-term phase (for example, marine invertebrate "settlement,"insect "adult eclosion," mushroom fruiting body emergence) wherethe actual habitat shift occurs. Disparate metamorphic taxadiffer substantially with respect to when the habitat shiftoccurs relative to the timing of the major events of morphogeneticchange. I will present comparative evidence across a broad taxonomicscope suggesting that longer-term processes (morphogenetic changes)are generally hormonally regulated, whereas nitric oxide (NO)repressive signaling often controls the habitat shift itself.Furthermore, new evidence from echinoids (sea urchins, sanddollars) indicates a direct connection between hormonal andNO signaling during metamorphosis. I incorporate 2 hypothesesfor the evolution of metamorphosisone involving heterochrony,the other involving phenotypic integration and evolutionarilystable configurations (ESCs)into a network model formetamorphosis in echinoderms (sea urchins, starfish, and theirkin). Early indications are that this core regulatory networkcan be acted upon by natural selection to suit the diverse ecologicalneeds of disparate metamorphic organisms, resulting in evolutionaryexpansions and contractions in the core network. I briefly speculateon the ways that exposure to xenobiotic pollutants and othercompounds might influence successful settlement of juvenilesin the wild. Indeed, environmentally regulated life historytransitionssuch as settlement, metamorphosis, and reproductivematurationmay be developmental periods that are especiallysensitive to such pollutants. 相似文献
15.
Accumulative disturbances can erode a coral reef's resilience, often leading to replacement of scleractinian corals by macroalgae or other non-coral organisms. These degraded reef systems have been mostly described based on changes in the composition of the reef benthos, and there is little understanding of how such changes are influenced by, and in turn influence, other components of the reef ecosystem. This study investigated the spatial variation in benthic communities on fringing reefs around the inner Seychelles islands. Specifically, relationships between benthic composition and the underlying substrata, as well as the associated fish assemblages were assessed. High variability in benthic composition was found among reefs, with a gradient from high coral cover (up to 58%) and high structural complexity to high macroalgae cover (up to 95%) and low structural complexity at the extremes. This gradient was associated with declining species richness of fishes, reduced diversity of fish functional groups, and lower abundance of corallivorous fishes. There were no reciprocal increases in herbivorous fish abundances, and relationships with other fish functional groups and total fish abundance were weak. Reefs grouping at the extremes of complex coral habitats or low-complexity macroalgal habitats displayed markedly different fish communities, with only two species of benthic invertebrate feeding fishes in greater abundance in the macroalgal habitat. These results have negative implications for the continuation of many coral reef ecosystem processes and services if more reefs shift to extreme degraded conditions dominated by macroalgae. 相似文献
16.
Marginal coral reef systems may provide valuable insights into the nature of ecosystem processes in systems on the trajectory
towards a phase shift to an alternate ecosystem state. This study investigates the process of herbivory in a marginal coral
reef system in the Keppel Islands at the southern end of the Great Barrier Reef. Branching Acropora coral and the brown macroalga Lobophora variegata occupied up to 95% of the reef crest substratum at the three surveyed reefs. Feeding rates of herbivorous fishes and removal
rates of Lobophora were directly quantified within areas of branching Acropora and on planar surfaces. Feeding rates by herbivorous fishes were habitat dependent with the highest bite rates being found
in planar habitats for both Lobophora and the epilithic algal matrix (EAM) by 1–2 orders of magnitude, respectively. Feeding rates on Lobophora were, however, much lower than rates on the EAM. The low rates of Lobophora removal and significantly lower rates of herbivory in branching habitats were consistent with the high biomass of this brown
alga throughout the Keppel Islands and with its distribution on reef crests, where Lobophora biomass was 20 times greater in branching than in planar habitats. This lack of feeding by herbivorous fishes within branching
coral habitats in the Keppel Islands contrasts with the typical role of coral and topographic complexity on herbivores on
coral reefs and highlights the potential for complex interactions between algae, corals and fishes on coral reefs. On marginal
systems, herbivory may modify algal distributions but may be unable to contain the proliferation of algae such as Lobophora. 相似文献
17.
Feeding diets and significance of coral feeding among Chaetodontid fishes in Moorea (French Polynesia) 总被引:4,自引:4,他引:0
The feeding diets of 18 Chaetodontid fishes from a coral reef of Moorea (French Polynesia) were studied by quantitative analysis
of their stomach contents. Three major types of feeding behaviours were distinguished. Sixteen species essentially ingested
coral polyps. Among these species, 5 were exclusive coral browsers and the others displayed more heterogeneous diets. One
species was a plankton feeder and the other consumed benthic invertebrates other than corals. The importance of coral consumption
on the reef by Chaetodontid fishes was estimated knowing the feeding diets and density of species in the various biota. Moreover,
the species which were previously observed as quantitatively dominant in the different reef zones, were found to be exclusive
coral browsers. Besides, the proportion between obligative and facultative coral feeders was found to be relatively constant
on the reef, emphasizing that a balance is established among the Chaetodontid species occupying the same habitat for the resource
partitioning. 相似文献
18.
Summary The roles of Permian colonial corals in forming organic reefs have not been adequately assessed, although they are common
fossils in the Permian strata. It is now known that colonial corals were important contributors to reef framework during the
middle and late Permian such as those in South China, northeast Japan, Oman and Thailand. A coral reef occurs in Kanjia-ping,
Cili County, Hunan, South China. It is formed by erect and unscathed colonies ofWaagenophyllum growing on top of one anotherin situ to form a baffle and framework. Paleontological data of the Cili coral reef indicates a middle to late Changhsing age (Late
Permian), corresponding to thePalaeofusulina zone. The coral reef exposure extends along the inner platform margin striking in E-S direction for nearly 4 km laterally
and generally 35 to 57 m thick. The Cili coral reef exhibits a lateral differentiation into three main reef facies; reef core
facies, fore-reef facies, and marginal slope facies. The major reef-core facies is well exposed in Shenxian-wan and Guanyin-an
sections where it rests on the marginal slope facies. Colonial corals are dispersed and preserved in non-living position easward.
Sponges become major stabilizing organisms in the eastern part of Changhsing limestone outcrop in Kanjia-ping, but no read
sponge reefs were formed. Coral reefs at Cili County in Human are different distinctly from calcisponge reefs in South China
in their palaeogeography, lithofacies development, organic constitutuents, palaeoecology and diagenesis. The Cili coral reef
also shows differences in age, depositional facies association, reef organisms and diagenesis from coral reefs in South Kitakami
of Japan, Khorat Plateau of Thailand, and Saih Hatat of Oman. Although some sponge reefs and mounds can reach up to the unconformable
Permian/Triassic boundary, coral reef at Kanjia-ping, Cili County, is the latest Permian reef known. This reef appears to
had been formed in a palaeoenvironment that is different from that of the sponge reefs and provides an example of new and
unique Permian reef type in South China, and could help us to: 1) understand the significance of colonial corals in Permian
carbonate buildups; 2) evaluate the importance of coral community evolution prior to the collapse of reef ecosystems at the
Permian/Triassic boundary; 3) better understand the effects of the biotic extinction events in Palaeotethys realm; 4) look
for environmental factors that may have controlled reefs through time and space, and 5) provide valuable data for the study
of Permian palaeoclimate and global evolutionary changes of Permian reefs and reef community. 相似文献
19.
Integrating individual behavior and population ecology: the potential for habitat-dependent population regulation in a reef fish 总被引:3,自引:1,他引:2
Levin Phillip S.; Tolimieri Nicholas; Nicklin Matthew; Sale Peter F. 《Behavioral ecology》2000,11(5):565-571
We used the predictions of the ideal free and ideal despoticdistributions (IFD and IDD, respectively) as a basis to evaluatethe link between spatial heterogeneity, behavior, and populationdynamics in a Caribbean coral reef fish. Juvenile three-spotdamselfish (Stegastes planifrons) were more closely aggregatedin patch reef habitat than on continuous back reef. Agonisticinteractions were more frequent but feeding rates were lowerin the patch versus the continuous reef habitat. Growth rateswere lower in patch reef habitat than on the continuous reef,but mortality rates did not differ. A separate experiment usingstandard habitat units demonstrated that the patterns observedin natural habitat were the result of the spatial distributionof the habitat patches rather than resource differences between
habitats. Our results do not follow the predictions of simpleIFD or IDD models. This deviation from IFD and IDD predictionsmay be the result of a number of factors, including lack ofperfect information about habitat patches, high movement costs,and higher encounter rates of dispersed patches. Our resultsdemonstrate that behavioral interactions are an integral partof population dynamics and that it is necessary to considerthe spatial organization of the habitat in both behavioraland ecological investigations. 相似文献
20.
Coral reefs in shallow-water environments (<30 m) are in decline due to local and global anthropogenic stresses. This has
led to renewed interest in the ‘deep reef refugia’ hypothesis (DRRH), which stipulates that deep reef areas (1) are protected
or dampened from disturbances that affect shallow reef areas and (2) can provide a viable reproductive source for shallow
reef areas following disturbance. Using the Caribbean as an example, the assumptions of this hypothesis were explored by reviewing
the literature for scleractinian corals—the reef framework builders on tropical reefs. Although there is evidence to support
that deep reefs (>30 m) can escape the direct effects of storm-induced waves and thermal bleaching events, deep reefs are
certainly not immune to disturbance. Additionally, the potential of deep reefs to provide propagules for shallow reef areas
seems limited to ‘depth-generalist’ coral species, which constitute only ~25% of the total coral biodiversity. Larval connectivity
between shallow and deep populations of these species may be further limited due to specific life history traits (e.g., brooding
reproductive strategy and vertical symbiont acquisition mode). This review exposes how little is known about deep reefs and
coral reproduction over depth. Hence, a series of urgent research priorities are proposed to determine the extent to which
deep reefs may act as a refuge in the face of global reef decline. 相似文献