Succession, space and coral recruitment in a subtropical fouling community

1999 ◽  
Vol 50 (3) ◽  
pp. 235 ◽  
Author(s):  
S. J. L. Fairfull ◽  
V. J. Harriott
Keyword(s):  
Multivariate Analysis ◽  
Species Richness ◽  
Community Structure ◽  
Recruitment Rate ◽  
Coral Recruitment ◽  
Fouling Community ◽  
Eastern Australia ◽  
Coral Communities ◽  
Over Time ◽  
Marine Community

Patterns of recruitment and succession on ceramic settlement panels were examined in a subtidal marine community in eastern Australia to determine whether competition for settlement space with temperate biota was a factor potentially limiting the development of coral communities in a subtropical location. Replicate settlement panels were installed at Split Solitary Island (30˚S) in November 1992 and were destructively sampled after 1, 3, 5, 7, 10, 12, 16 and 29 months. Species richness and community structure data were analysed by non-parametric multivariate analysis. Space on panel surfaces was rapidly occupied; the upper surfaces by algae and the lower surfaces by bryozoans, ascidians and sponges, with a divergence of community structure over time. Of the 228 coral recruits identified on the panels, 98% were recorded on the upper surface of panels, in contrast to studies at most tropical sites where corals recruit predominantly to lower surfaces. Owing to the rapid settlement of other biota, free space for coral settlement was limited and this may account for the low coral recruitment rate recorded. High post-settlement mortality (>94%) of coral recruits over a 3-month period indicated the significance of post-settlement factors in accounting for low recruitment in settlement-panel studies.

scholarly journals Coral communities condition in varying wave exposure: the gulf of Cazones, Cuba

2016 ◽  
Vol 64 (1) ◽  
pp. 79 ◽  
Author(s):  
Hansel Caballero Aragon ◽  
Pedro M Alcolado ◽  
Néstor Rey-Villiers ◽  
Susana Perera Valderrama ◽  
Juliett González Méndez
Keyword(s):  
Species Richness ◽  
Community Structure ◽  
Marine Protected Area ◽  
Coral Cover ◽  
Coral Community ◽  
Wave Exposure ◽  
Maximum Diameter ◽  
Live Coral ◽  
Coral Mortality ◽  
Coral Communities

Wave exposure can influence community structure and distribution of shallow coral reefs, by affecting organisms both directly and indirectly. To assess the current stony coral community condition under different degrees of wave exposure at a marine protected area of the Gulf of Cazones (SW Cuba), two expeditions were carried out in May 2010 and June 2012. Four sampling sites were sampled at reef crests (1.5 m deep), and twelve at fore-reefs, at 10, 15 and 20 m deep in four geographic locations. Live coral cover, species richness and composition, colony density, and maximum diameter were assessed using the AGRRA 2001 methodology. Multivariate and non-parametric statistics were applied to compare sites. The coral community structure within reef crests was not homogenous. The observed variability of indicators apparently was determined by great coral mortality events resulting from natural disturbances that occurred in the past (hurricanes, bleaching and diseases). Fore-reef coral communities displayed better condition and lower coral mortality than reef crests. Species richness and coral composition varied, while multivariate and statistical methods did not reveal site grouping with regard to wave exposure. The remaining biological condition indicators were similar among sites, except in the most exposed one, where coral cover and coral size were slightly lower. Wave exposure in the gulf of Cazones seemed not to have a significant influence on differences in condition and structure of the assessed coral communities.

Divergent responses to long-term grazing exclusion among three plant communities in a flood pulsing wetland in eastern Australia.

2014 ◽  
Vol 20 (3) ◽  
pp. 237 ◽  
Author(s):  
Peter J Berney ◽  
G. Glenn Wilson ◽  
Darren S. Ryder ◽  
R.D.B Whalley ◽  
John Duggin ◽  
...  
Keyword(s):  
Species Richness ◽  
Community Composition ◽  
Plant Community ◽  
Plant Communities ◽  
Dominant Species ◽  
Grass Species ◽  
Grazing Exclusion ◽  
Eastern Australia ◽  
Domestic Livestock ◽  
Over Time

We examined the effects of grazing exclusion over a period of 14 years on the species richness and community composition of three plant communities with different dominant species and water regimes in the Gwydir Wetlands in eastern Australia. Responses to grazing exclusion varied among the three plant communities, and were most likely to be evident during dry periods rather than during periods of inundation. In frequently flooded plant communities, there was an increase in phytomass following exclusion of domestic livestock, but changes in plant community composition and species richness due to livestock exclusion varied depending on the morphological attributes of the dominant plant species. In a plant community where tall sedge species were dominant, livestock exclusion further increased their dominance and overall species richness declined. In contrast, where a prostrate grass species such as Paspalum distichum was dominant, species richness increased following livestock exclusion, due to an increase in the abundance of taller dicotyledon species. However, livestock exclusion in a community where flooding was less frequent and native grass species have been largely replaced with the introduced species Phyla canescens, resulted in no significant changes to phytomass, species richness or community composition among the grazing exclusion treatments over time. Our results indicate responses to exclusion of domestic livestock are dependent upon the dominant species within the plant community and will likely vary over time with the extent of wetland inundation. Grazing exclusion alone, without increased flooding, is unlikely to restore floristically degraded floodplain plant communities.

scholarly journals Preliminary foraminiferal survey in Chichiriviche de La Costa, Vargas, Venezuela

2021 ◽  
Vol 24 (2) ◽  
pp. 90-103
Author(s):  
Humberto Carvajal-Chitty ◽  
Sandra Navarro
Keyword(s):  
Multivariate Analysis ◽  
Species Richness ◽  
Community Structure ◽  
Diversity Index ◽  
Local Communities ◽  
Basic Information ◽  
Wiener Diversity Index ◽  
Prone Area ◽  
Preliminary Study ◽  
General Community

A preliminary study of the composition and community structure of the foraminifera of Chichiriviche de La Costa (Vargas, Venezuela) is presented. A total of 105 species were found in samples from 10 to 40 meter-depth, and their abundance quantified in a carbonate prone area almost pristine in environmental conditions. The general composition varies in all the samples: at 10 m, Miliolida dominates the assemblages but, as it gets deeper, Rotaliida takes control of the general composition. The Shannon Wiener diversity index follows species richness along the depth profile, meanwhile the FORAM index has a higher value at 20 m and its lowest at 40 m. Variations in the P/(P+B) ratio and high number of rare species are documented and a correspondence multivariate analysis was performed in order to visualize the general community structure. These results could set some basic information that will be useful for management programs associated with the coral reef in Chichiriviche de La Costa, which is the principal focus for diver’s schools and tourism and could help the local communities to a better understanding of their ecosystem values at this location at Vargas State, Venezuela. Keywords: Miliolida, Rotaliida, foraminiferal assemblages, FORAM index, Caribbean continental shelf.

USING FOOD WEBS TO UNDERSTAND THE EFFECTS OF BIOTIC INVASION ON LATE ORDOVICIAN MARINE COMMUNITY STRUCTURE

2017 ◽  
Author(s):  
Hannah L. Kempf ◽  
◽  
Ian O. Castro ◽  
Carrie L. Tyler ◽  
Ashley A. Dineen ◽  
...  
Keyword(s):  
Community Structure ◽  
Food Webs ◽  
Late Ordovician ◽  
Biotic Invasion ◽  
Marine Community

Community characteristics of forest understory birds along an elevational gradient in the Horn of Africa: A multi-year baseline

The Condor ◽  
2021 ◽  
Author(s):  
Kyle D Kittelberger ◽  
Montague H C Neate-Clegg ◽  
Evan R Buechley ◽  
Çağan Hakkı Şekercioğlu
Keyword(s):  
Species Richness ◽  
Species Turnover ◽  
Survival Rates ◽  
Elevational Gradient ◽  
Forest Understory ◽  
Bird Abundance ◽  
Tropical Mountains ◽  
Demographic Rates ◽  
Understory Birds ◽  
Over Time

Abstract Tropical mountains are global hotspots for birdlife. However, there is a dearth of baseline avifaunal data along elevational gradients, particularly in Africa, limiting our ability to observe and assess changes over time in tropical montane avian communities. In this study, we undertook a multi-year assessment of understory birds along a 1,750 m elevational gradient (1,430–3,186 m) in an Afrotropical moist evergreen montane forest within Ethiopia’s Bale Mountains. Analyzing 6 years of systematic bird-banding data from 5 sites, we describe the patterns of species richness, abundance, community composition, and demographic rates over space and time. We found bimodal patterns in observed and estimated species richness across the elevational gradient (peaking at 1,430 and 2,388 m), although no sites reached asymptotic species richness throughout the study. Species turnover was high across the gradient, though forested sites at mid-elevations resembled each other in species composition. We found significant variation across sites in bird abundance in some of the dietary and habitat guilds. However, we did not find any significant trends in species richness or guild abundances over time. For the majority of analyzed species, capture rates did not change over time and there were no changes in species’ mean elevations. Population growth rates, recruitment rates, and apparent survival rates averaged 1.02, 0.52, and 0.51 respectively, and there were no elevational patterns in demographic rates. This study establishes a multi-year baseline for Afrotropical birds along an elevational gradient in an under-studied international biodiversity hotspot. These data will be critical in assessing the long-term responses of tropical montane birdlife to climate change and habitat degradation.

Large-scale patterns in species richness and composition of temperate riverine fish communities, south-eastern Australia

2000 ◽  
Vol 51 (2) ◽  
pp. 165 ◽  
Author(s):  
Peter C. Gehrke ◽  
John H. Harris
Keyword(s):  
Species Richness ◽  
Large Scale ◽  
Fish Communities ◽  
Fish Fauna ◽  
South Coast ◽  
North Coast ◽  
Large Spatial Scale ◽  
River Types ◽  
Eastern Australia ◽  
Riverine Fish

Riverine fish in New South Wales were studied to examine longitudinal trends in species richness and to identify fish communities on a large spatial scale. Five replicate rivers of four types (montane, slopes, regulated lowland and unregulated lowland) were selected from North Coast, South Coast, Murray and Darling regions. Fishwere sampled during summer and winter in two consecutive years with standardized gear that maximized the range of species caught. The composition of fish communities varied among regions and river types, with little temporal variation. Distinct regional communities converged in montane reaches and diverged downstream. The fish fauna can be classified into North Coast, South Coast, Murray and Darling communities, with a distinct montane community at high elevations irrespective of the drainage division. Species richness increased downstream in both North Coast and South Coast regions by both replacement and the addition of new species. In contrast, species richness in the Darling and Murray regions reached a maximum in the slopes reaches and then declined, reflecting a loss of species in lowland reaches. The small number of species is typical of the freshwater fish faunas of similar climatic regions world-wide. Fish communities identified in this study form logical entities for fisheries management consistent with the ecosystem-focused, catchment-based approach to river management and water reform being adopted in Australia.

scholarly journals Effect of fire on a monodominant floating mat of Cyperus giganteus Vahl in a neotropical wetland

2015 ◽  
Vol 75 (1) ◽  
pp. 114-124 ◽  
Author(s):  
M. Rocha ◽  
CC. Santos Júnior ◽  
GA. Damasceno-Júnior ◽  
VJ. Pott ◽  
A. Pott
Keyword(s):  
Species Richness ◽  
Community Structure ◽  
Annual Variation ◽  
Floristic Composition ◽  
Large Area ◽  
Characteristic Species ◽  
Cyperus Giganteus ◽  
Pantanal Wetland ◽  
Floating Mat ◽  
Adult Plants

The rhizomatous Cyperus giganteus, abundant in the Pantanal wetland, can dominate extense floodable areas as monodominant communities. The Jacadigo lake has a large area of C. giganteus, where we performed an evaluation on community structure during two months in 2010, before it was hit by a wildfire which top-killed the vegetation, compared to ten months post-fire. We utilized 40 plots of 1m × 1m, along permanent trails, assessing two strata: the upper, near the inflorescence of adult plants, and the lower, close to the water level. Our results show that fire does not affect dominance of C. giganteus, as it maintained the same cover as before fire; species richness is not much altered either - 28 before fire and 34 thereafter. Fire changed the floristic composition, due to the annual variation of species and the ability of some plants to colonize gaps and to regrow after fire from underground organs and seeds. The stratification of the vegetation with characteristic species of upper and lower strata was similar after fire.

Diverse perennial crop mixtures sustain higher productivity over time based on ecological complementarity

2011 ◽  
Vol 26 (4) ◽  
pp. 317-327 ◽  
Author(s):  
Valentín D. Picasso ◽  
E. Charles Brummer ◽  
Matt Liebman ◽  
Philip M. Dixon ◽  
Brian J. Wilsey
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Biomass Production ◽  
Cropping Systems ◽  
Individual Species ◽  
Selection Effects ◽  
Complementarity Effect ◽  
Change Over Time ◽  
Diversity Effects ◽  
Over Time

AbstractCropping systems that rely on renewable energy and resources and are based on ecological principles could be more stable and productive into the future than current monoculture systems with serious unintended environmental consequences such as soil erosion and water pollution. In nonagricultural systems, communities with higher species diversity have higher productivity and provide other ecosystem services. However, communities of well-adapted crop species selected for biomass production may respond differently to increasing diversity. Diversity effects may be due to complementarity among species (complementary resource use and facilitative interactions) or positive selection effects (e.g., species with higher productivity dominate the mixture), and these effects may change over time or across environments. Our goal was to identify the ecological mechanisms causing diversity effects in a biodiversity experiment using agriculturally relevant species, and evaluate the implications for the design of sustainable cropping systems. We seeded seven perennial forage species in a replicated field experiment at two locations in Iowa, USA, and evaluated biomass productivity of monocultures and two- to six-species mixtures over 3 years after the establishment year under management systems of contrasting intensity: one or three harvests per year. Productivity increased with seeded species richness in all environments, and the positive relationship did not change over time. Polyculture overyielding was due to complementarity among species in the community rather than to selection effects of individual species. Complementarity increased as a log-linear function of species richness in all environments, and this trend was consistent across years. Legume–grass facilitation may explain much of this complementarity effect. Although individual species with high biomass production had a major effect on productivity of mixtures, the species producing the highest biomass in monoculture changed over the years in most environments. Furthermore, transgressive overyielding was observed and was more prevalent in later years, in some environments. We conclude that choosing a single well-adapted species for maximizing productivity may not be the best alternative over the long term and that high levels of species diversity should be included in the design of productive and ecologically sound agricultural systems.

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