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  • 1
    Electronic Resource
    Electronic Resource
    Overlap in resource use, and interspecific competition (1974)
    Springer
    Oecologia 17 (1974), S. 245-256 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary When several species co-exist, the amount by which they overlap in their use of resources is a measure of their similarity to one another. As such, resource overlap does not measure the amount of competition among them. When the resources are not limiting to population growth, patterns of resource use may overlap to any degree. However, when the species are frequently in competition for their resources, natural selection will favor the separation of their requirements, and the amount of resource overlap will be reduced. This paper presents a technique which permits comparison of the amount of resource overlap observed in a given case with that expected for a group of similar species co-existing in the absence of competitive interactions. From this comparison can be evaluated the likelihood of competitive processes being important in the situation under study.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00344924
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  • 2
    Electronic Resource
    Electronic Resource
    Ecological structure of assemblages of coral reef fishes on isolated patch reefs (1994)
    Springer
    Oecologia 98 (1994), S. 83-99 
    Details
    ISSN: 1432-1939
    Keywords: Coral reef fish ; Community structure ; Patch reef ; Community dynamics ; Recruitment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A 9-year study of the structure of assemblages of fish on 20 coral patch reefs, based on 20 non-manipulative censuses, revealed a total of 141 species from 34 families, although 40 species accounted for over 95% of sightings of fish. The average patch reef was 8.5 m2 in surface area, and supported 125 fish of 20 species at a census. All reefs showed at least a two-fold variation among censuses in total numbers of fish present, and 12 showed ten-fold variations. There was also substantial variation in the composition and relative abundances of species present on each patch reef, such that censuses of a single patch reef were on average about 50% different from each other in percent similarity of species composition (Czekanowski's index). Species differed substantially in the degree to which their numbers varied from census to census, and in the degree to which their dispersion among patch reefs was modified from census to census. We characterize the 40 most common species with respect to these attributes. The variations in assemblage structure cannot be attributed to responses of fish to a changing physical structure of patch reefs, nor to the comings and goings of numerous rare species. Our results support and extend earlier reports on this study, which have stressed the lack of persistant structure for assemblages on these patch reefs. While reef fishes clearly have microhabitat preferences which are expressed at settlement, the variations in microhabitat offered by the patch reefs are insufficient to segregate many species of fish by patch reef. Instead, at the scale of single patch reefs, and, to a degree, at the larger scale of the 20 patch reefs, most of the 141 species of fish are distributed without regard to differences in habitat structure among reefs, and patterns of distribution change over time. Implications for general understanding of assemblage dynamics for fish over more extensive patches of reef habitat are considered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00326094
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  • 3
    Electronic Resource
    Electronic Resource
    Determinants of community structure for coral reef fishes in isolated coral heads at lagoonal and reef slope sites (1978)
    Springer
    Oecologia 34 (1978), S. 57-74 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Ten small isolated corals were selected as units, of habitat in each of two nearby reef sites-a lagoon and a reef slope. On six occasions over two years we collected all fishes resident in each of these corals. Collections yielded 827 fishes of 64 species from the lagoon and 525 fishes of 66 species from the slope, but at each site 12 common species comprised over 80% of the fishes collected. We examined the distribution of species of fishes among units of habitat to assess the extent to which partitioning of habitat was being carried out. Results are compared with others previously reported from a reef flat site. Species discriminated among different types of habitat offered, but to a different degree in each site. Discrimination was most pronounced at the slope site where 7 of the 12 commonest species did not occur in all three types of habitat offered, and least at the lagoon site where no common species failed to occupy both types of habitat offered. No temporal partitioning of habitat could be demonstrated. Fish did not distribute themselves among units of habitat of one type by means of precise microhabitat discrimination. No pair of species in either site could be shown to mutually avoid, or exclude one another from habitat units. At all three sites, chance patterns of recruitment and loss overwhelmingly determined species composition of the groups of fishes coexisting in single habitat units. The significance of these results for our understanding of the ecology of coral reef fishes is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00346241
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  • 4
    Electronic Resource
    Electronic Resource
    Recruitment, loss and coexistence in a guild of territorial coral reef fishes (1979)
    Springer
    Oecologia 42 (1979), S. 159-177 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Eupomacentrus apicalis, Plectroglyphidodon lacrymatus, and Pomacentrus wardi are territorial pomacentrid fishes which occupy contiguous individual territories within rubble patches on the shallow reef slope. Loss of residents, which is non-seasonal (except for juvenile Po. wardi), results in reallocation of space in rubble patches among the species. This reallocation is random in the sense that sites previously held by one species will not be more likely than any other sites to be reoccupied by that species or to be occupied by any other particular species. The results of a 38 month study of three neighbouring patches are used to determine patterns of recruitment, survivorship, and loss for each species. The rate of recruitment of fish is proportional to the area of the rubble patch, and is seasonal in at least one of the species. About half the recruits are juveniles and young adults from other sites. The others are newly settled from the plankton. Total space used in a rubble patch does not vary significantly during the 38 month period. Po. wardi recruits and is lost at higher rates than the other species and its survivorship is significantly lower. Juvenile Po. wardi are lost at a greater rate than are adults, and their loss rate varies seasonally. The other species are similar to one another in having low recruitment and loss rates, and correspondingly high survivorship. The data are used in a critical assessment of several competing hypotheses to explain the coexistence of these fish. The available data are most closely compatible with the chance allocation or lottery hypothesis, but a definitive conclusion is not possible, and is probably beyond current experimental techniques.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00344855
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  • 5
    Electronic Resource
    Electronic Resource
    Coral reefs Recruitment in space and time (1999)
    [s.l.] : Macmillan Magazines Ltd.
    Nature 397 (1999), S. 25-27 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Six years ago, in an address to the Ecological Society of America, Simon Levin wrote that “the problem of pattern and scale is the central problem in ecology, unifying population biology and ecosystem science, and marrying basic and applied ecology”. Interest in scale effects has ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/16158
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  • 6
    Electronic Resource
    Electronic Resource
    Patterns and processes in reef fish diversity (2003)
    [s.l.] : Macmillian Magazines Ltd.
    Nature 421 (2003), S. 933-936 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] A central aim of ecology is to explain the heterogeneous distribution of biodiversity on earth. As expectations of diversity loss grow, this understanding is also critical for effective management and conservation. Although explanations for biodiversity patterns are still a matter for intense ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/nature01393
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  • 7
    Electronic Resource
    Electronic Resource
    Choice of microhabitats by coral reef fishes at settlement (1984)
    Springer
    Coral reefs 3 (1984), S. 91-99 
    Details
    ISSN: 1432-0975
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract A set of small lagoonal patch reefs was searched every 1 to 3 days during the peak recruitment seasons of three summers and newly settled juvenile fishes were located. The majority of species remain rather sedentary during the first few days in the demersal environment, and we assumed that the site occupied was the site chosen at settlement. A series of characteristics of the occupied site were recorded, including percent cover of different types of substratum, and attributes related to the site's position on the patch reef. A set of null sites was randomly located on the same reefs for comparison with those selected by the fish. Sites chosen by individuals of eight common species were compared with these null sites, and sites chosen by fourteen species (including the eight) were compared with each other. Multiple discriminant analysis was used to assess the degree to which each species selected a unique type of site, and, for the eight species, the degree to which sites chosen by fish could be discriminated from randomly selected sites on the same patch reefs. Chosen sites were readily discriminated from null sites in seven of eight species, however the procedure was poor at discriminating among sites chosen by different species, and 8 pairs of species among the 14 chose sites which on average did not differ in the attributes measured. Attributes most important in discriminating sites chosen by each species are considered. Overall, the results indicate that while juvenile fish do not settle indiscriminantly onto lagoonal patch reefs, sites chosen by different species are often not very different from one another.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00263759
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  • 8
    Electronic Resource
    Electronic Resource
    Early survivorship of juvenile coral reef fishes (1988)
    Springer
    Coral reefs 7 (1988), S. 117-124 
    Details
    ISSN: 1432-0975
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Data on early survivorship of newly settled reef fish were collected by monitoring individuals which recruited to 30 small lagoonal patch reefs over three summers. Preliminary survivorship curves spanning the first 45 days after settlement were derived for 17 species. Most species showed greatest rates of mortality in the first 1–2 weeks in the reef environment however there were substantial differences among species in the extent and the temporal pattern of this. In six species, 75% of individuals survived the 45 days, while in 5 others, 20% or fewer survived that long. In eight species, mortality was negligible after the first 14 days. In the other 9, significant mortality occurred in subsequent weeks. Patterns of survivorship did not appear to differ substantially among years in five of the six species for which data were adequate. In particular, survivorship did not appear to be different among years even when levels of recruitment varied greatly.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00300971
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  • 9
    Electronic Resource
    Electronic Resource
    Persistence of community structure: what happens when you change taxonomic scale? (1992)
    Springer
    Coral reefs 11 (1992), S. 147-154 
    Details
    ISSN: 1432-0975
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract It is common in community ecology to use the species as the taxonomic category of interest, yet in rich tropical assemblages containing guilds of very similar species this may not be appropriate. Such assemblages may be organized at the level of guilds rather than at the finer species level. In a ten-year study of assemblages of fish at One Tree Reef, Great Barrier Reef, we found species composition and the number of fish on a given lagoonal patch reef vary greatly across time (Sale and Douglas 1984; Sale et al. in preparation). The mean average proportional similarity of a reef's assemblage to itself at different times (censuses) is usually low at a value of around 0.5. This apparent variability may be ecologically irrelevant noise if organization is at the higher guild level. We have recast our database at the guild level to test this possibility. Thirteen guilds were defined by the diets, foraging habitats and times of the individual species comprising them. Similarity of an assemblage to itself at successive censuses was re-calculated using the number of individuals in each guild instead of the numbers in each species. This analysis yielded significantly higher levels of similarity (P〈0.01) among censuses. To test whether this increase in similarity was due solely to the smaller number of categories used to calculate the similarity indices, 5 sets of randomly generated guilds were constructed using a Monte Carlo approach. No significant difference (P〉0.05) was found between the average similarity among censuses when assemblages were classified into these “null” guilds and when they were classified according to the real guilds. These results indicate that shifting to the “larger” taxonomic scale of guilds does not reveal a significantly more persistent assemblage structure than that revealed when analysis is at the “smaller” scale of species. There is no evidence of an underlying organization of these assemblages at the guild level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00255469
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  • 10
    Electronic Resource
    Electronic Resource
    Predation on juvenile coral reef fishes: an exclusion experiment (1986)
    Springer
    Coral reefs 4 (1986), S. 225-234 
    Details
    ISSN: 1432-0975
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract The densities of recruits on caged and uncaged areas were compared in an experiment done to show the extent of predation on recently metamorphosed coral reef fishes. The design was unlike typical caging experiments, however, in that areas were caged only for short periods of 20–30 days and several independent trials, testing the same null hypothesis, were run. This was done to avoid confounding the effects of excluding herbivorous fishes with the effects of excluding piscivorous fishes. A third treatment, partially-meshed cages, revealed that the experiment was complicated by several other factors. Some prey species were attracted to the high relief offered by the experimental structures. Others responded to the differences in shelter from predators by redispersing themselves among the treatments shortly after settlement. There was also at least one significant “edge” effect caused by fishes preferring to settle near the boundaries of all treatments. In spite of these difficulties, observations on known individuals revealed that rates of mortality were age-dependent and decreased rapidly after metamorphosis. More than 25% of such fishes disappeared during their first five days in the benthic habitat compared with 〉10% of fishes aged 6–10 days and no losses of fishes aged 11–15 days. These early losses are the greatest instantaneous rates of mortality yet documented for recruited reef fishes. The experiment also suggested different rates of early mortality for various groupings of species: individuals of solitary, sedentary species disappeared approximately half as fast as individuals of the more mobile, and the more gregarious, species. This is probably a true reflection of the different vulnerability of these groups to predation and it may be caused by the different ways in which these fishes use the coral substratum. Our experience suggests that caging artifacts can have major impacts on the results obtained from this type of experiment and they must be controlled for adequately. We conclude that studies of predation on reef fishes may be done more easily using other methods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00298081
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