Dominance Of Single Species Research Articles

What determines the number of dominant species in forests?

In this work, the difference in number of dominant species in a community on global scale and successional trajectories was analyzed based on the published data. We explained the reasons of these differences using a resource availability hypothesis, proposed in this work, that the distribution of available resource determined the pattern of community dominance. The results showed that on global scale the number of dominant species of community varied across latitudinal forest zone, namely from single-species dominance in boreal and temperate forest to multi-species codominance, even no dominant species in tropical forest. This was consistent with the pattern of resource distribution on global scale. Similarly, in successional trajectories, the number of dominant species gradually radiated from single-species dominance to multi-species codominance, even no dominant species in tropical forest. The changing available resources in trajectories were responsible for this difference. By contrary, a community was often dominated by single species in temperate or boreal forest. This was determined by the low available resource, especially low available water and temperature. In boreal forest, low temperature greatly reduced availability of water and nutrient, which were responsible for the single-species dominance. In addition, the conclusion that high available resources sustained low dominance of community might be deduced, based on the fact that the dominance of community declined with the increasing of species diversity. To sum up, the richer the available resources were, the lower the dominance of community was, and vice versa. The hypothesis that the resource availability controlled the dominance of community could well elucidate the difference of community dominance on global and community scale.

Formalized classification of the vegetation of Abies alba-dominated forests in the Czech Republic

AbstractA phytosociological classification of silver fir (Abies alba) forests in the Czech Republic was carried out using the Braun-Blanquet approach. It is based on the formalized and supervised Cocktail classification method. The definitions of associations were created by combinations of sociological species groups using logical operators. Dominance of single species was included in the definitions of associations. All relevés with at least 50% cover of silver fir in tree layer available from the Czech Republic were used for analysis. Three associations within two classes were distinguished. Vaccinio vitis-idaeae-Abietetum albae (Vaccinio-Piceetea, Piceion excelsae) is an oligotrophic, species-poor spruce-pine-fir forest dominated by Vaccinium myrtillus in the herb layer occurring mostly on podzols. Luzulo-Abietetum albae (Querco-Fagetea, Luzulo-Fagion) is an oligo-mesotrophic spruce-fir forest characterized by the dominance of graminoids (Luzula luzuloides, Calamagrostis arundinacea) in the herb layer. It occurs especially on cambisols. Nutrient-demanding species are typical of the stands of herb-rich mesotrophic Galio rotundifolii-Abietetum albae (Querco-Fagetea, Fagion sylvaticae, Galio rotundifolii-Abietenion) that occurs also mostly on cambisols. Soil nutrients and soil reaction (represented by Ellenberg indicator values) were determined as the most important ecological gradients affecting the variation of the vegetation in these communities.

Dynamics of Microbial Growth and Coexistence on Variably Saturated Rough Surfaces

The high degree of microbial diversity found in soils is attributed to the highly heterogeneous pore space and the dynamic aqueous microenvironments. Previous studies have shown that spatial and temporal variations in aqueous diffusion pathways play an important role in shaping microbial habitats and biological activity in unsaturated porous media. A new modeling framework was developed for the quantitative description of diffusion-dominated microbial interactions focusing on competitive growth of two microbial species inhabiting partially saturated rough surfaces. Surface heterogeneity was represented by patches with different porosities and water retention properties, yielding heterogeneous distribution of water contents that varies with changes in relative humidity or soil matric potential. Nutrient diffusion and microbial growth on the variably hydrated and heterogeneous surface was modeled using a hybrid method that combines a reaction diffusion method for nutrient field with individual based model for microbial growth and expansion. The model elucidated the effects of hydration dynamics and heterogeneity on nutrient fluxes and mobility affecting microbial population growth, expansion, and coexistence at the microscale. In contrast with single species dominance under wet conditions, results demonstrated prolonged coexistence of two competing species under drier conditions where nutrient diffusion and microbial movement were both limited. The uneven distribution of resources and diffusion pathways in heterogeneous surfaces highlighted the importance of position in the landscape for survival that may compensate for competitive disadvantages conferred by physiological traits. Increased motility was beneficial for expansion and survival. Temporal variations in hydration conditions resulted in fluctuations in microbial growth rate and population size. Population growth dynamics of the dominant species under wet-dry cycles were similar to growth under average value of diffusion coefficients for dry and wet conditions, respectively, suggesting that the time-averaged diffusion coefficient could serve as a useful indicator for estimation of microbial activities in a highly dynamic system such as that found in soils.

Effects of cutting Phragmites australis along an inundation gradient, with implications for managing reed encroachment in a South African estuarine lake system

Substantive encroachment of Phragmites australis (common reed) occurred since the 1970s in the Wilderness estuarine lakes, a National Park and Ramsar site. Cutting of reeds in late summer as a means of controlling reed encroachment was investigated under three different inundation regimes, termed ‘wet zone’ (permanently inundated), ‘moist zone’ (infrequently inundated) and ‘dry zone’ (rarely inundated). The effects of a single annual cut were furthermore compared to those of two successive annual cuts. Without cutting, wet zones had thinner and shorter, but more abundant reeds than drier zones. Cutting in dry and moist zones resulted after one year in more, but shorter and thinner reeds, whereas in wet zones reeds were almost eliminated. After two years, reeds in wet zones had not recovered from the first annual cut. In moist and dry zones, a second annual cut did not result in amplified detrimental effects on reeds. Throughout the experiment, moisture zone was the factor with the largest effect, cutting had the second largest impact, and inter-annual variation was relatively unimportant. We have demonstrated that cutting alone has minimal long-term effect on above-ground reed biomass, whereas reed growth and survivorship can be strongly suppressed through cutting in late-summer in conjunction with inundation with moderately saline water (5.0–7.5 g kg−1). Cut reeds must remain completely inundated for at least a four-week period, or else emerging shoots should be re-cut below the water level. Cut material should be removed from the treatment site. Whenever possible, cutting and inundation should be undertaken to coincide with periods when salinity levels of surface waters are higher. It is foreseen that reed management in the Wilderness Lakes would have positive effects on other biota by countering progression towards single species domination of wetland plant communities and reinstating exposed sandbanks which are extensively utilised by resident and migratory waterbirds.

Is plant biodiversity driven by decomposition processes? An emerging new theory on plant diversity

Diversity of forest trees ranges from monospecific stands to the astonishing richness of tierra firma tropical forests. Such patterns are observed along gradients of latitude, altitude, soil fertility and rainfall. So far, the proposed coexisting mechanisms do not provide a comprehensive and unequivocal explanation of these patterns at the community level. We propose a new theory linking species diversity with organic matter cycle and negative plant-soil feedback induced by litter autotoxicity. This approach focuses on resource-waste rather than resource-only dynamics. High diversity does occur where litter decomposition is rapid and ecosystem nutrient cycles are closed. On the other hand, single species dominance is found where litter decomposition is slow and/or autotoxicity is removed from the nutrient cycle pathway. Unlike previous theoretical views, the one we present proves potentially capable of explaining differences in species diversity both along environmental gradients and within the tropics.

Parasite communities of eels Anguilla anguilla in freshwater and marine habitats in Iceland in comparison with other parasite communities of eels in Europe

Ninety-five eels from one marine and three freshwater localities in Iceland were examined for parasites. Twenty species were found, 12 from marine habitat, 12 from freshwater and 4 species were found in both habitats. These are: Eimeria anguillae, Chilodonella hexasticha, Trichodina fultoni, T. jadranica, Myxidium giardi, Myxobolus kotlani, two Zschokkella spp., Derogenes varicus, Deropristis inflata, Diplostonmum sp., Plagioporus angulatus, Podocotyle atomon, Anisakis simplex (larva), Eustrongylides sp. (larva), Hysterothylacium aduncum (larva), Raphidascaris acus (larval and adult stages), Bothriocephalus claviceps, Proteocephalus macrocephalus, and a pseudophyllidean larva. Thirteen of these species are new parasite records from Icelandic waters. The component community of marine eels was characterized by low diversity and a high dominance of a single species. Overall, seven species of helminths were observed, up to five different species occurring in an individual fish. The component community of the freshwater eels was species-poor with low diversity and relatively high dominance of single species. A between-sites difference in the freshwater eels was considerable; only Diplositonun sp. was found at more then one sampling site. Similar to previous studies, there is a total replacement of freshwater macroparasite species by marine ones in saline waters. But unlike research abroad in which species richness decreases with higher salinity, the marine eels in Iceland have considerably higher richness than the freshwater ones. The parasite communities of freshwater eels in Iceland are, in general species-poorer, less diverse and having higher Berger Parker (BP) dominance than other eel communities in Europe. Marine eels have on the other hand comparable species richness, are less diverse and with a high BP dominance.

Effects of cutting Phragmites australis along a flooding gradient, with implications for managing reed encroachment in a South African estuarine lake system

Substantive encroachment of Phragmites australis (common reed) occurred since the 1970s in the Wilderness estuarine lakes, a National Park and Ramsar site. Cutting of reeds in late summer as a means of controlling reed encroachment was investigated under three different inundation regimes, termed ‘wet zone’ (permanently inundated), ‘moist zone’ (infrequently inundated) and ‘dry zone’ (rarely inundated). The effects of a single annual cut were furthermore compared to those of two successive annual cuts. Without cutting, wet zones had thinner and shorter, but more abundant reeds than drier zones. Cutting in dry and moist zones resulted after one year in more, but shorter and thinner reeds, whereas in wet zones reeds were almost eliminated. After two years, reeds in wet zones had not recovered from the first annual cut. In moist and dry zones, a second annual cut did not result in amplified detrimental effects on reeds. Throughout the experiment, moisture zone was the factor with the largest effect, cutting had the second largest impact, and inter-annual variation was relatively unimportant. We have demonstrated that cutting alone has minimal long-term effect on above-ground reed biomass, whereas reed growth and survivorship can be strongly suppressed through cutting in late-summer in conjunction with inundation with moderately saline water (5.0–7.5 g kg−1). Cut reeds must remain completely inundated for at least a four-week period, or else emerging shoots should be re-cut below the water level. Cut material should be removed from the treatment site. Whenever possible, cutting and inundation should be undertaken to coincide with periods when salinity levels of surface waters are higher. It is foreseen that reed management in the Wilderness Lakes would have positive effects on other biota by countering progression towards single species domination of wetland plant communities and reinstating exposed sandbanks which are extensively utilised by resident and migratory waterbirds.

Intra-specific density dependence is required to maintain species diversity in spatio-temporal forest simulations with reproduction

Including explicitly the link between parent trees and recruitment is indispensable for many forest model applications, e.g. for simulating tree species migrations. However this positive feedback can result in unrealistic dominance of single species. We examine in which way this feedback can be modelled to maintain species diversity and species composition similar to observed forests. A submodel of the spatio-temporal forest model TreeMig for simulating seed production, seed dispersal, seed bank dynamics and sapling development is presented. With the extended model, interactions of different factors that can influence species diversity in a forest are examined. In simulations under different bioclimatic conditions of Switzerland differential hypotheses for maintaining species diversity are tested. The simulated species diversity and dominant species are compared to data compiled from the Swiss National Forest Inventory. Intra-specific density regulation is necessary to produce in the simulations a species diversity and species composition similar to data. Without this intra-specific density dependence, strong seed producers, such as birch ( Betula pendula) dominate the stand, in contrast to the data, and decrease species diversity. With intra-specific density regulation, species diversity is further increased by spatial or temporal variability. Temporal variability in environmental factors alone can enhance species diversity, if the factors fluctuate between the favourable and unfavourable range of the strong seed producers.

Anthropogenic disturbances and plant biodiversity in forests of Uttaranchal, central Himalaya

Eight forest types varying in disturbance frequencies were identified along an elevational gradient in Uttaranchal, central Himalaya. Low elevation forests were close to human habitation and had high disturbance frequency, while high elevation forests were situated far from the human habitation and had low disturbance. The dominant tree species at low elevation were Pinus roxburghii and Quercus leucotrichophora, while Q. floribunda and Q. semecarpifolia dominated the high elevation forests. Pyracantha crenulata was the shrub present in all the forests except in Q. semecarpifolia forest and Anaphalis contorta, a herb species, was present in all the forests. Disturbance decreased the dominance of single species and increased the plant biodiversity by mixing species of different successional status. Species richness and diversity for all the vegetation layers were higher in low elevation–high disturbance forests. Mean tree density decreased from high to moderate and increased in low disturbance. The shrub density decreased from high to low disturbance while the reverse occured for herbs. High proportion of early successional species in disturbed forests indicated that disturbance induces succession. The mean number of young individuals increasing from high to low disturbance indicates that disturbance adversely affects regeneration. But, however, the high number of young individuals of Coriaria nepalensis, a small non-leguminous nitrogen fixing tree, in disturbed forests shows that the forest is regenerating. This species could be helpful in the re-establishment of original vegetation through triggering the regeneration of these forests. High elevation–low disturbed forests separated from low elevation–high disturbed forests. Forest type and elevation may have more influence on tree richness while shrub and herb richness may be more sensitive to disturbance and forest types.

Are plantations changing the tree species composition of New Brunswick's forest?

Forest plantations are viewed by some as a means to meet the world's escalating demand for wood, and by others as a threat to forest diversity and ecological function. With the purpose of improving planting practices, we analysed recently available data on 15- to 30-year-old plantations on public land in New Brunswick to identify tree species composition differences between plantations and the natural forest they replaced. Presently, 9% of the public forests in the province has been planted; at current planting rates, this will increase to 17% by the year 2030. Plantations established between 1967 and 1982 differ little from the natural forest they replaced in terms of total softwood content, but differ markedly by having much higher jack pine and much lower red spruce contents. There is evidence of reduced diversity evenness in plantations at the landscape level, but at the stand level few plantations are true monocultures and the abundance of high single-species dominance in plantations is very similar to that of the natural forests they replaced. All species composition comparisons between plantations and replaced natural forest vary strongly by ecoregion. To reduce the degree of difference between plantations and the natural forest, planting practices and prescriptions should (a) broaden the mix of species used, and use less jack pine and more red spruce and cedar, (b) employ a mix of species at the stand level, and (c) consider more fully the site conditions and natural species composition of ecological zones. Key words: plantations, tree species composition, forest simplification, tree species diversity, forest management

Scales and consequences of human land transformation on South African avian diversity and structure

Species diversity and community structure indices (richness, diversity and evenness) are typically derived from contemporary biological survey atlases to identify conservation areas or to determine macroecological-environment relationships. Surprisingly, there are few studies based on national taxa surveys that describe and measure the influence human disturbance patterns may have on these ecological measures. This study uses various spatial statistical methods to examine and model large-scale spatial structure in diversity, structure indices derived from a comprehensive bird atlas, and composite variables of environment and human land transformation. Data were derived from an atlas of South African birds and segregated into five vegetation biomes. For each sample location, environmental and land-use data were used to calculate composite environmental gradients in climate, topography and human land transformation. Semivariograms were used to detect large-scale trends and spatial scale, and Moran's I statistic correlograms to test for large-scale spatial autocorrelation in detrended diversity indices. Ordinary least squares regressions for all biomes indicated a significant positive relationship between high levels of human transformation and species diversity, whereas high transformation had a significant negative influence on evenness. These same relationships held for the majority of biomes after the effects of environmental gradients were removed. The analysis also shows that in areas with favourable environmental resource levels, diversity for birds increases. These areas also tend to contain a large proportion of highly transformed land, and evenness decreases in the woodland, grassland, Karoo and fynbos biomes. This suggests that high-intensity transformation may bring in novel resources for birds not normally found in some of the biomes, with some species adept at exploiting these changes and reaching high densities with a tendency for assemblage structure to drift towards single species dominance. The results imply that species data derived from contemporary atlases may begin to demonstrate the effects of human influence on ecological measures rather than only indicating the effects of environmental variation on community structure.

Plant species diversity and tree population structure of a humid tropical forest in Tamil Nadu, India

Vegetation structure and species composition of tropical ecosystems were studied through nine transects at Veerapuli and Kalamalai reserve forests in the Western Ghats of Tamil Nadu, India. Species diversity, dominance, species richness and evenness indices of plant communities and also population structure of woody plants were enumerated. A total of 244 species (183 genera and 76 families) were recorded. Species richness (number of species) were 82,142 and 96 species per 0.3 ha respectively for the study areas of low-elevation forest (LEF), mid-elevation forest (MEF) and high elevation forest (HEF). Species diversity indices were greater in MEF compared to the other two forests except juveniles. In contrast, greater dominance value indices were recorded in LEF than other forests. Density and basal area of the MEF were twice greater than the LEF, while HEF showed greater tree density and low basal area when compared to LEF. The stem density and species richness (number of species) decreased with increased size classes of trees observed in the present study indicated good regeneration status. Population structure of juveniles and seedlings also reflects good regeneration status. Terminalia paniculata (IVI of 99.9) and Hopea parviflora (IVI of 103.8) were dominant tree species respectively in LEF and MEF whereas in HEF Agrostistachys meeboldii (63.65), Cullenia excelsa (63.67) and Drypetes oblongifolia (39.67) share the dominance. Past damage (anthropogenic perturbation) may be one of the reasons for single species dominance in LEF and MEF. Occurrence of alien species such as Eupatorium odoratum and Ageratum conyzoides also indicated the past disturbance in LEF. The variations in plant diversity and population structure are largely due to anthropogenic perturbation and other abiotic factors.

Quaternary surface water temperature estimations: Calibration of a diatom transfer function for the Southern Ocean

The quantitative diatom analysis of 218 surface sediment samples recovered in the Atlantic and western Indian sector of the Southern Ocean is used to define a base of reference data for paleotemperature estimations from diatom assemblages using the Imbrie and Kipp transfer function method. The criteria which justify the exclusion of samples and species out of the raw data set in order to define a reference database are outlined and discussed. Sensitivity tests with eight data sets were achieved evaluating the effects of overall dominance of single species, different methods of species abundance ranking, and no‐analog conditions (e.g., Eucampia Antarctica) on the estimated paleotemperatures. The defined transfer functions were applied on a sediment core from the northern Antarctic zone. Overall dominance of Fragilariopsis kerguelensis in the diatom assemblages resulted in a close affinity between paleotemperature curve and relative abundance pattern of this species downcore. Logarithmic conversion of counting data applied with other ranking methods in order to compensate the dominance of F. kerguelensis revealed the best statistical results. A reliable diatom transfer function for future paleotemperature estimations is presented.

Effects of acidification on 0+ juvenile fish diversity and abundance in River Kyrönjoki, Finland

The objectives of this study were to determine the effects of acidification on 0+ juvenile fish diversity and abundance in River Kyrönjoki in 1995 and 1996. Species diversity and abundance data were obtained from seine hauls in aquatic vegetation biotopes of nymphaeids predominantly Nuphar lutea. Acidity levels decreased steadily from May to August in 1995. In 1996, acidity levels increased during May, July and early August. Acidification levels were related to low abundances of 0+ juveniles, except for 0+juvenile (Esox Incites L.) in the estuary, and lower species richness in the 0+ fish community in the river in 1996. Single species dominance, expressed as rank abundance curves, was typical in the river's 0+ juvenile fish community during the acidification in 1996.

Vegetation types of the deltaic Mediterranean coast of Egypt and their environment

Abstract. The delta section of the Mediterranean coast of Egypt canbe divided ecologically into four main habitats: salt marsh, sand formation, reed swamp and fertile non‐cultivated land. In each habitat vegetation types can be distinguished based on the dominance of single species. The salt marsh habitat comprises five such communities dominatedby: Zygophyllumaegyptium, inula crithmoides, Arthrocnemum macrostachyum, Juncus acutus and Ha‐locnemum strobilaceum. The vegetation of the sand formation includes 11 communities dominatedby: Elymus farctus ssp.farctus, Alhagigraecorum, Cynodon dactylon, Heliotropium curassavicum, Stipagrostis lanata, Thyme‐laea hirsuta, Moltkiopsis ciliata, Asparagus stipularis and Pancratium maritimum (sand dunes), Cressa crética and Phragmites australis (sand flats). The reed swamp habitat is dominated by Typha domingensis. In the fertile non‐cultivatedlandAlhagigraecorum, Cynodon dactylon and Heliotropium curassavicum are the dominants.Quantitative cluster analysis revealed a lower number of clusters than there are dominance types, but on the whole the two systems are similar.Ordination and subsequent analysis of correlation between vegetation gradients and soilfactors showed that the decisive soil factors for the variation in salt marsh vegetation are moisture availability and CaC03 content, and for the sand formation soil moisture, ‐ fertility and ‐ salinity.

Evidence for rapid faunal changes on islands in a man-made lake : I. Ants.

Few studies of island biogeography have been made on islands in which the time of insularization is precisely known. We tested the effects of island formation on ant species diversity in a man-made lake in South Africa, to determine whether island effects are detectable after only 16 years of insularization. The number of ant species observed at trap-line censuses on islands was significantly correlated with island size (r=0.608; P<0.05) and ant species diversity was generally low compared with similar mainland habitats. Mean species number for all islands, including landbridge islands, was 5.5±3.3 species, and on mainland sites was 7.9±2.85 species. Island effects were more marked on islands <20 ha, which had a mean of 3.3±2.5 species per island. Species number on islands was inversely related to densities of the aggressive Anoplolepis custodiens and A. steingroeveri. These two species were only patchily distributed on mainlands, but these ants were nearly ubiquitous on small islands. Several lines of evidence suggest that this single species domination may be responsible for island effects. Island sites also differed in the number of ant species in different trophic groupings, tending to have fewer granivorous species than the mainland sites, but species in other diet groups were similar in both island and mainland habitats. We conclude that there have been marked changes in the ant faunas on islands smaller than 20 ha apparently due to changes in abundance of the dominant ant species. However, the causes of these changes are unknown.

Single-species dominance in a subsurface phytoplankton concentration at a Mediterranean Sea front

A narrow band of high Chl a (23.1 µg liter−1) was observed at a salinity front in the western Mediterranean Sea in late November 1987. The biomass peak was found deep in the photic zone, at 54 m, in a region of low light. A single diatom species, Thalassiosira partheneia Schrader in gelatinous colonies, represented 98% of the total phytoplankton biomass in the layer and achieved abundances >9.8 × 106 cells liter−1. Although lack of temporal sampling precludes precise determination of the processes responsible, the high biomass accumulation and dominance by this species was likely due to its preference for low light coupled with turbulence-induced high nutrient levels. Interleaving patterns in the temperature, salinity, and nutrient profiles suggest increased horizontal advection at the front. High shear at the boundaries of the interleavings might confine the biomass to a thin band, as well as generate turbulence to mix nutrients in from surrounding layers. Alternatively, stabilization of the water column following a brief, pulsed upwelling event could have reduced dispersion of the biomass, thereby confining it to the thin layer we observed.

Stemonoporus(Dipterocarpaceae)-dominated montane forests in the Adam's Peak Wilderness, Sri Lanka

ABSTRACTStemonoporusThw. (Dipterocarpaceae), a genus endemic to Sri Lanka, contains as many as 26 species, all but one confined to the perhumid forests of the island. Several species reach 1800 m, the highest altitude recorded for any dipterocarp species in Sri Lanka. We report the first quantitative data onStemonoporus-domirated stands in the montane zone (1500–1700 m).Stemonoporus cordifoliusand 5.rigidusshow clear single-species dominance of their respective stands.Stemonoporus gardneriis a co-dominant withPalaquium rubiginosumin its two stands. AllStemonoporusspecies appear to have a unique geographical and ecological range and no twoStemonoporusspecies co-exist in our stands.

Structure and function of the Central Himalayan oak forests

Oak (Quercus spp.) forests represent the climax evergreen vegetation between 1000–3600 m in the Central Himalaya. Shrub layer is well developed in these forests and phanerophytes prevail (50–60%). Though one oak species mixes frequently with other oak species, or conifers, the single-species dominance is quite common. All the oak forests are vulnerable to fire. They support a great variety of wildlife. Coppicing subsequent to cutting is well developed in all oak species and helps them in regeneration. However, because of severe biotic stress oaks are failing to regenerate in forest stands. The forest biomass ranges between 294–787 t ha−1 and the net primary productivity generally between 16–21 t ha−1 yr−1. Oak forests store a large proportion of their nutrients in biomass component. Leaves are nutrient-rich and decompose rapidly. Evergreen woody species with concentrated summer leaf drop prevail in oak forests. The seasonality of the ecosystem activities seem to be influenced by the monsoon pattern of rainfall. Though the recovery is rapid after the forest destruction, because of continuous and severe biotic stress, oaks are being replaced with other communities.

The first year in the life history and the survival of the juvenile marine macrophyte, Ecklonia radiata (Turn.) J. Agardh

Small Ecklonia radiata (Turn.) J. Agardh plants were tagged in March 1979 and observed monthly for 1 yr. Growth appeared related to the amount of light received by the plants. Plants in shaded areas showed little growth. Plants in unshaded positions grew to full size in 8 months, showing an exponential growth curve with time. Unshaded plants went through three morphological stages; a juvenile first stage at settlement, a second stage observed within the 1st month and a mature stage reached 4 months after tagging. When canopy plants were cleared artificially, small repressed plants responded by developing rapidly. A larger (36 m 2) artificial clearing was not re-vegetated by E. radiata for at least 9 months after clearing. The survival of the marine E. radiata is compared with survival of seedlings in terrestrial forests. Different types of disturbance and their effects on the community are discussed to explain the single-species dominance of E. radiata on the reef.