Comparing the Complete Hierarchical Structuration of Species Abundances in Reef Fish Communities According to Coral Morphology, Using the Numerical Extrapolation of Only Incomplete Inventories

Growing complexity of coral habitat is expected to increase resource partitioning among co-occurring reef fish and, thereby, reduce to some extent the mean competitive intensity. This will have associated consequences on the internal structuring of species in reef fish communities, in particular regarding species richness and evenness of species abundances. Accumulating dedicated case studies are necessary, however, to get further empirical confirmations. The present analysis aims to contribute in this respect, comparing reef fish communities associated to two coral-reef settings that markedly differ in their degree of morphological complexity, at Itaipu Sound, Brazil. As the available samplings of these communities remained incomplete, numerical extrapolations were implemented, thereby providing least-bias estimates for both total species richness and the exhaustive distribution of species abundances in both compared reef fish communities. As expected, total species richness increases with greater degree of coral habitat complexity, while the unevenness of species abundances decreases. This decrease in abundance unevenness – reflecting the corresponding relaxation of the mean level of competitive intensity – is partly due to the direct, negative influence of species richness on abundance unevenness, as an overall trend. Beyond that, however, the relaxation is further strengthened by an additional “genuine” contribution – this time independent from the variation in species richness – and, as such, directly and idiosyncratically attached to the improvement in habitat complexity.

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Influence of Fishing Activity on Total Species Richness and Abundance Unevenness in Reef Fish Communities: A Case Study in a Brazilian Tropical Coral Complex

International Journal of Environment and Climate Change ◽

10.9734/ijecc/2019/v9i130097 ◽

2019 ◽

pp. 58-76

Author(s):

Jean Béguinot

Keyword(s):

Species Richness ◽

Reef Fish ◽

Fish Communities ◽

Fishing Activity ◽

Total Species Richness ◽

Tropical Coral ◽

Species Abundances ◽

Hierarchical Structuring ◽

Species Richness And Abundance ◽

Total Species

The internal organization of reef-fish communities, particularly the species richness and the hierarchical structuring of species abundances, depends on many environmental factors, including fishing intensity and proportion of macroalgal cover which are expected to have determinant influences. However, reported studies on this topic are generally based on incomplete samplings (almost unavoidable in practice when dealing with highly uneven and species-rich communities), so that the derived results can be appreciably skewed. To overcome this difficulty, the incomplete samplings involved in this study were completed numerically through a reliable extrapolation procedure. This precaution provided a safe confirmation that reduced fishing activity and increased macroalgae cover both contribute to enhance the total species richness and to reduce the abundance unevenness in these reef fish communities. Yet, it is shown that this reduction of abundance unevenness is almost entirely attributable to the increase in species richness.

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Dominance determines fish community biomass in a temperate seagrass ecosystem

10.32942/osf.io/cqjvu ◽

2019 ◽

Author(s):

Aaron Matthius Eger ◽

Rebecca J. Best ◽

Julia Kathleen Baum

Keyword(s):

Species Richness ◽

Ecosystem Function ◽

Fish Community ◽

Prey Capture ◽

Fish Communities ◽

Functional Trait ◽

Ecosystem Functions ◽

Community Biomass ◽

Ecosystem Valuation ◽

Species Abundances

Biodiversity and ecosystem function are often correlated, but there are multiple hypotheses about the mechanisms underlying this relationship. Ecosystem functions such as primary or secondary production may be maximized by species richness, evenness in species abundances, or the presence or dominance of species with certain traits. Here, we combined surveys of natural fish communities (conducted in July and August, 2016) with morphological trait data to examine relationships between diversity and ecosystem function (quantified as fish community biomass) across 14 subtidal eelgrass meadows in the Northeast Pacific (54° N 130° W). We employed both taxonomic and functional trait measures of diversity to investigate if ecosystem function is driven by species diversity (complementarity hypothesis) or by the presence or dominance of species with particular trait values (selection or dominance hypotheses). After controlling for environmental variation, we found that fish community biomass is maximized when taxonomic richness and functional evenness is low, and in communities dominated by species with particular trait values – those associated with benthic habitats and prey capture. While previous work on fish communities has found that species richness is positively correlated with ecosystem function, our results instead highlight the capacity for regionally prevalent and locally dominant species to drive ecosystem function in moderately diverse communities. We discuss these alternate links between community composition and ecosystem function and consider their divergent implications for ecosystem valuation and conservation prioritization.

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Community changes of coral reef fishes in Bunaken National Park, North Sulawesi, Indonesia

AQUATIC SCIENCE & MANAGEMENT ◽

10.35800/jasm.1.2.2013.7273 ◽

2013 ◽

Vol 1 (2) ◽

pp. 117

Author(s):

Fakhrizal Setiawan ◽

Janny D Kusen ◽

Georis JF Kaligis

Keyword(s):

Reef Fish ◽

National Park ◽

Fish Community ◽

Time Series Data ◽

Coral Cover ◽

Fish Communities ◽

Reef Fishes ◽

Series Data ◽

Fish Community Structure ◽

Reef Fish Community

In order to look at changes in coral and reef fish communities during the period of 2006 to 2013, this research was carried out at Bunaken National Park (BNP) with 26 observation sites. The existing data and information of reef fish communities in the park generally could not be used as representative for describing the whole region. Percentage of coral cover and fish abundance during the study period shows that Bunaken Island is more similar to other locations. Reef fish community structure as seen from ecological index (H' at all sites being categorized, E category labile and low category C) shows the condition of the reef fish community is still good. Changes in the structure of reef fish communities showed declining conditions compared to 2006, and coral cover continued to decrease compared to 1998 and 2007. Good overall reef fish and coral cover have decreased; it is thought to be related to the pressure in BNP. Some of the pressures in the region were (i) increasing numbers of domestic as well as foreign visitors, (ii) increasing number of residents in the region, as well as the burden of waste and trash from the Bay of Manado. Penelitian dilakukan di Taman Nasional Bunaken (Utara dan Selatan) pada 26 lokasi pengamatan untuk menganalisis perubahan struktur komunitas ikan karang melalui kajian dari suatu time series data dari beberapa penelitian sebelumnya. Data primer mengenai ikan-ikan karang diperoleh melalui visual sensus bawah air yang bersamaan dengan observasi terumbu karang menggunakan point intercept transect. Nilai persentase tutupan karang dan kelimpahan ikan menunjukkan bahwa pada lokasi pengamatan Pulau Bunaken paling baik dibandingan lokasi lainnya. Struktur komunitas ikan karang yang dianalisis dengan indeks ekologi menunjukkan indeks keanekaragaman (H’) di semua site masuk kategori sedang, indeks kesamaan (E) kategori labil dan indeks Dominansi (C) kategori rendah. Hasil penelitian ini menunjukkan bahwa kondisi komunitas ikan karang masih baik, sekalipun perubahan struktur komunitas ikan karang menunjukkan kondisi yang menurun dibandingkan tahun 2006, begitu juga tutupan karang yang terus turun dibandingkan tahun 1998 dan 2007. Secara keseluruhan baik ikan karang maupun tutupan karang mengalami penurunan, hal ini diduga terkait dengan tekanan yang dialami kawasan TN. Bunaken. Salah satu tekanan terhadap kawasan adalah jumlah turis dari dalam maupun luar negeri yang semakin meningkat tiap tahunnya, penambahan jumlah penduduk di dalam kawasan, serta beban limbah dan sampah dari Teluk Manado.

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Effects of trap fishing on reef fish communities

Aquatic Conservation Marine and Freshwater Ecosystems ◽

10.1002/aqc.784 ◽

2007 ◽

Vol 17 (2) ◽

pp. 111-132 ◽

Cited By ~ 20

Author(s):

Julie P. Hawkins ◽

Callum M. Roberts ◽

Fiona R. Gell ◽

Calvin Dytham

Keyword(s):

Reef Fish ◽

Fish Communities

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Coral degradation and the structure of tropical reef fish communities

Marine Ecology Progress Series ◽

10.3354/meps333243 ◽

2007 ◽

Vol 333 ◽

pp. 243-248 ◽

Cited By ~ 44

Author(s):

DA Feary ◽

GR Almany ◽

GP Jones ◽

MI McCormick

Keyword(s):

Reef Fish ◽

Fish Communities ◽

Tropical Reef

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Inferring True Species Richness and Complete Abundance Distribution in Six Reef-fish Communities from Red-sea, Using the Numerical Extrapolation of Incomplete Samplings

Asian Journal of Environment & Ecology ◽

10.9734/ajee/2019/v11i330136 ◽

2019 ◽

pp. 1-21

Author(s):

Jean Beguinot

Keyword(s):

Reef Fish ◽

Red Sea ◽

Field Data ◽

Full Range ◽

Species Abundance ◽

Fish Communities ◽

Ecological Communities ◽

Abundance Distribution ◽

Internal Organization ◽

Unrecorded Species

Even when ecological communities are incompletely sampled (which is most frequent in practice, at least for species-rich assemblages including many rare species), it remains possible to retrieve much more information than could be expected first, by applying numerical extrapolation to incomplete field data. Indeed, recently developed procedures of numerical extrapolation of partial samplings now allow to estimate, with fair accuracy, not only the number of the still unrecorded species but, moreover, the distribution of abundances of each of these unrecorded species, thereby making available the full range of the Species Abundance Distribution, despite dealing with incomplete data only. In turn, this allows to address a series of descriptive and functional aspects of the internal organization of species assemblages, which otherwise would have required disposing of truly exhaustive samplings. This approach is applied, here, to the previously reported partial samplings of six neighboring reef-fish communities from Tiran Island, Red Sea, with the goal of better understanding their internal organization in relation to their respective environments. In practice, the numerical completion contributes to avoid erroneous interpretations that would likely stem from considering only the incomplete field data. This point is especially relevant when studying reef-associated communities because accurate understanding of their organization will help guiding and refining at best the protective measures required by these particularly vulnerable communities.

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