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  • 1
    Electronic Resource
    Electronic Resource
    Predation and the Control of the Sea Urchin Echinometra viridisand Fleshy Algae in the Patch Reefs of Glovers Reef, Belize (1999)
    Springer
    Ecosystems 2 (1999), S. 511-523 
    Details
    ISSN: 1435-0629
    Keywords: Key words: carnivory; Echinometra viridis; ecological redundancy; fleshy algae; herbivory; sea urchin predators.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: ABSTRACT The massive reduction in sea urchin Diadema antillarum populations since the mid-1980s has been associated with large increases in the abundance of fleshy algae on many Caribbean reefs despite the availability of other sea urchin and finfish grazers. This study examined the ecology of a grazer living sympatrically with D. antillarum, the common and abundant sea urchin Echinometra viridis. I examined the role that finfish and invertebrate predators play in controlling the distribution of E. viridis as well as the ability of this sea urchin to control exposed fleshy algae on the patch reefs of the Glovers Reef Atoll lagoon. I found that the major predators of this sea urchin were Calamus bajonado (jolthead porgy), Balistes vetula and Canthidermis sufflamen (queen and ocean triggerfish), Lachnolaimus maximus (hogfish), and a gastropod, probably Cassis madagascariensis. The abundance of E. viridis is constrained by predation, which restricts E. viridis to cryptic locations, such as crevices. Sea urchins bit a smaller percentage of experimental algal assays than finfish. Finfish herbivory was associated positively with patch reef topographic complexity. Unexpectedly, E. viridis abundance was positively correlated with fleshy algal abundance, but negatively correlated with the frequency of finfish bites. Predators restrict E. viridis to crevices and therefore reduce their influence on exposed fleshy algae, even at moderately high population densities (up to 10 per square meter). Since net benthic primary production of coral reefs is most strongly associated with herbivory on exposed surfaces, it would appear that E. viridis is unable to maintain the same production as reefs dominated by D. antillarum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s100219900099
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  • 2
    Electronic Resource
    Electronic Resource
    Endemic survives adversity (1994)
    Springer
    Coral reefs 13 (1994), S. 104-104 
    Details
    ISSN: 1432-0975
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00300769
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  • 3
    Electronic Resource
    Electronic Resource
    Varying responses of herbivorous and invertebrate-feeding fishes to macroalgal reduction on a coral reef (1999)
    Springer
    Coral reefs 18 (1999), S. 195-203 
    Details
    ISSN: 1432-0975
    Keywords: Key words Algae ; Carnivory ; Coral reef fishes Herbivory ; Restoration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract  The consequences of macroalgal overgrowth on reef fishes and means to reverse this condition have been little explored. An experimental reduction of macroalgae was conducted at a site in the Watamu Marine National Park in Kenya, where a documented increase in macroalgal cover has occurred over the last nine years. In four experimental 10 m by 10 m plots, macroalgae were greatly reduced (fleshy algal cover reduced by 84%) by scrubbing and shearing, while four similar plots acted as controls. The numerical abundance in all fish groups except wrasses and macroalgal-feeding parrotfishes (species in the genera Calotomus and Leptoscarus) increased in experimental algal reduction plots. Algal (Sargassum) and seagrass (Thalassia) assays, susceptible to scraping and excavating parrotfishes, were bitten more frequently in the algal reduction plots one month after the manipulation. Further, surgeonfish (Acanthurus leucosternon and A. nigrofuscus) foraging intensity increased in these algal reduction plots. The abundance of triggerfishes increased significantly in experimental plots relative to control plots, but densities remained low, and an index of sea urchin predation using tethered juvenile and adult Echinometra mathaei showed no differences between treatments following macroalgal reduction. Dominance of reefs by macrofleshy algae appears to reduce the abundance of fishes, mostly herbivores and their rates of herbivory, but also other groups such as predators of invertebrates (triggerfishes, butterflyfishes and angelfishes).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003380050181
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  • 4
    Electronic Resource
    Electronic Resource
    Kenyan coral reef-associated gastropod assemblages: distribution and diversity patterns (1990)
    Springer
    Coral reefs 9 (1990), S. 63-74 
    Details
    ISSN: 1432-0975
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract A survey of Kenya's shallow water (〈2 m) coral reef-associated prosobranch fauna was undertaken to determine patterns of distribution, density, diversity and species richness, and the possible role of other reef fauna and human utilization on these patterns. The sample assemblage of 135 species from 25 families is similar to other Indian Ocean regions with no apparent endemism or subregional faunal affinities. Species richness, determined by species-individual relationships, has been reduced by approximately 45% since the Pleistocene. Northern Kenya, typified by small coral islands experiencing river and estuarine discharges had low densities and species richness and high species variability. This is attributable to the interrelated factors of river discharge, small reefs and reduced predator refuge. Southern Kenya's more expansive fringing reef has a denser and richer fauna but appears less species rich than Tanzania. Variation within reefs suggests similarities in diversity between reef lagoons, flats and edges, but lagoons had lower densities than reef flat or edge sites. This is attributable to greater predation rates within lagoons. Species composition between reef locations was variable but differed for comparisons between reef lagoons and reef flats. The population densities of thirty commercially collected species were compared between shelled and unshelled reefs. Only two commercial strombids, Lambis truncata and L. chiragra, had lower densities within shelled compared to unshelled reefs. Within six southern Kenvan reef lagoons, total gastropod densities were negatively correlated with the Balistidae (triggerfish) and total fish densities and positively with sea urchin densities. The removal of balistids through fishing appears to lead to co-occurring population increases in gastropod and sea urchin populations which, in most instances, appears to negate the effect of shell collecting.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00368801
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  • 5
    Electronic Resource
    Electronic Resource
    Ligand for FLT3/FLK2 receptor tyrosine kinase regulates growth of haematopoietic stem cells and is encoded by variant RNAs (1994)
    [s.l.] : Nature Publishing Group
    Nature 368 (1994), S. 643-648 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] To develop an assay for the FLT3/FLK2 ligand (FL) and to identify producer cells, we transfected the pro-B cell line Ba/F3 (ref. 6) with a cDNA clone encoding mouse FLT3/FLK2. Stable transformants, called Baflt, were then used as target cells in a proliferation assay with conditioned medium from ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/368643a0
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  • 6
    Electronic Resource
    Electronic Resource
    Kenyan coral reef lagoon fish: effects of fishing, substrate complexity, and sea urchins (1994)
    Springer
    Coral reefs 13 (1994), S. 231-241 
    Details
    ISSN: 1432-0975
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Population density, number of species, diversity, and species-area relationships of fish species in eight common coral reef-associated families were studied in three marine parks receiving total protection from fishing, four sites with unregulated fishing, and one reef which recently received protection from fishing (referred to as a transition reef). Data on coral cover, reef topographic complexity, and sea urchin abundance were collected and correlated with fish abundance and species richness. The most striking result of this survey is a consistent and large reduction in the population density and species richness of 5 families (surgeonfish, triggerfish, butterflyfish, angelfish, and parrotfish). Poor recovery of parrotfish in the transition reef, relative to other fish families, is interpreted as evidence for competitive exclusion of parrotfish by sea urchins. Reef substrate complexity is significantly associated with fish abundance and diversity, but data suggest different responses for protected versus fished reefs, protected reefs having higher species richness and numbers of individuals than unprotected reefs for the same reef complexity. Sea urchin abundance is negatively associated with numbers of fish and fish species but the interrelationship between sea urchins, substrate complexity, coral cover, and management make it difficult to attribute a set percent of variance to each factor-although fishing versus no fishing appears to be the strongest variable in predicting numbers of individuals and species of fish, and their community similarity. Localized species extirpation is evident for many species on fished reefs (for the sampled area of 1.0 ha). Fifty-two of 110 species found on protected reefs were not found on unprotected reefs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00303637
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  • 7
    Electronic Resource
    Electronic Resource
    Is there a future for coral reef parks in poor tropical countries? (1999)
    Springer
    Coral reefs 18 (1999), S. 321-325 
    Details
    ISSN: 1432-0975
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003380050205
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  • 8
    Electronic Resource
    Electronic Resource
    Causes and consequences of sea urchin abundance and diversity in Kenyan coral reef lagoons (1990)
    Springer
    Oecologia 83 (1990), S. 362-370 
    Details
    ISSN: 1432-1939
    Keywords: Community structure ; Coral reefs ; Predation ; Sea urchins ; Triggerfish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Large differences in community structure of sea urchins and finfish have been observed in Kenyan reef lagoons. Differences have been attributed to removal of finfish predators through human fishing activities. This study attempted to determine (i) the major sea urchin finfish predators, (ii) the effect of predation on sea-urchin community structure, and (iii) the possible effect of sea urchin increases and finfish decreases on the lagoonal substrate. Six reefs, two protected and four unprotected, were compared for differences in finfish abundance, sea urchin abundance and diversity and substrate cover, diversity and complexity. Comparisons between protected and unprotected reefs indicated that finfish populations were ca. 4 x denser in protected than unprotected reefs. Sea urchin populations were 〉100 x denser and predation rates on a sea urchin, Echinometra mathaei, were 4 x lower in unprotected than in protected reefs. The balistidae (triggerfish) was the single sea-urchin finfish predator family which had a higher population density in protected than in unprotected reefs. Balistid density was positively correlated with predation rates on tethered E. mathaei (r=0.88; p〈0.025) and negatively correlated with total sea-urchin density (r=−0.89; p〈0.025) on the six reefs. We conclude from observations that the balistids Balistaphus undulatus and Rhinecanthus aculeatus are the dominant sea-urchin predators. The sea-urchin assemblage had its greatest diversity and species richness at intermediate predation rates and low to intermediate sea-urchin densities. At low predation rates and high sea-urchin density E. mathaei dominated the assemblage's species composition. Preferential predation on the competitive dominant maintains the assemblage's diversity, supporting the compensatory mortality hypothesis (Connell 1978) of coral reef diversity. Protected reefs had greater cover of hard coral, calcareous and coralline algae, and greater substrate diversity and topographic complexity than unprotected reefs which had greater algal turf and sponge cover. Coral cover and topographic complexity were negatively correlated with total sea urchin density. Although experimentation is lacking, these substrate changes may be due to the switch from finfish to sea-urchins as consumers which results from overfishing of finfish. Removal of top invertebrate-eating carnivores appears to have cascading effects on the entire coral reef ecosystem.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00317561
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  • 9
    Electronic Resource
    Electronic Resource
    Coral and sea urchin assemblage structure and interrelationships in Kenyan reef lagoons (1994)
    Springer
    Hydrobiologia 286 (1994), S. 109-124 
    Details
    ISSN: 1573-5117
    Keywords: coral reefs ; community structure ; diversity ; human impacts ; marine parks ; species richness
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Patterns of hard coral and sea urchin assemblage structure (species richness, diversity, and abundance) were studied in Kenyan coral reef lagoons which experienced different types of human resource use. Two protected reefs (Malindi and Watamu Marine National Parks) were protected from fishing and coral collection, but exposed to heavy tourist use. One reef (Mombasa MNP) received protection from fishermen for one year and was exploited for fish and corals prior to protection and was defined as a ‘transitional reef’. Three reefs (Vipingo, Kanamai, and Diani) were unprotected and experienced heavy fishing and some coral collection. Protected and unprotected reefs were distinct in terms of their assemblage structure with the transitional reef grouping with unprotected reefs based on relative and absolute abundance of coral genera. Protected reefs had slightly higher (p〈0.01) coral cover (23.6 ± 8.3 % ± S.D.) than unprotected reefs (16.7 ± 8.5), but the transitional reef had the highest coral cover (30.8 ± 6.4) which increased by 250% since measured in 1987: largely attributable to a large increase inPorites nigrescens cover. Protected reefs had higher coral species richness and diversity and a greater relative abundance ofAcropora, Montipora andGalaxea than unprotected reefs. The transitional reef had high species richness, but lower diversity due to the high dominance ofPorites. Sea urchins showed the opposite pattern with highest diversity in most unprotected reefs. Coral cover, species richness, and diversity were negatively associated with sea urchin abundance, but the relative abundance ofPorites increased with sea urchin abundance to the point wherePorites composed 〉90% of the coral cover at sites with the highest sea urchin abundance. Effects of coral overcollection was only likely for the genusAcropora (staghorn corals). A combination of direct and indirect effects of human resource use may reduce diversity, species richness, and abundance of corals while increasing the absolute abundance of sea urchins and the relative cover ofPorites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00008501
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  • 10
    Electronic Resource
    Electronic Resource
    Dispersal of ornithochorous seeds from forest edges in central Florida (1987)
    Springer
    Plant ecology 71 (1987), S. 107-112 
    Details
    ISSN: 1573-5052
    Keywords: Bird diversity ; Frugivory ; Ornithochory ; Recruitment ; Seed dispersal ; Succession ; Vegetation structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Dispersal of ornithochorous seeds from isolated forests in the phosphate mining region of central Florida, U.S.A., were studied for two seasons (July to November) to determine patterns of dispersal. Three separate studies included (1) dispersal directly from forest edges to early successional herbs; (2) standardized perches (2 m high post with a crossbeam); and (3) snags (dead trees, 11.3±2.8 m high, 21.4±23.3 stem branches). Perch availability was more important than distance in predicting seed types and quantities of bird-dispersed seeds. The greatest concentration of bird-dispersed seeds were found under standard perches (255±249 seeds/m2/fall) followed by snags (147±85 seeds/m2/fall) and early successional vegetation (3.0±4.1 seeds/m2/fall). Seed quantities dispersed to snags were positively correlated with the number of stem branches on snags. Seeds beneath standard perches were significantly lighter and less diverse than those found beneath snags. This difference is attributed to the larger percentage of forest or later successional species found beneath snags (73%) as compared to the standard perches (15%). Perches and vegetative structural development should facilitate ecological succession by increasing the quantity, quality and diversity of seed deposition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00044824
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