Difference in the trophic structure of fish communities between artificial and natural habitats in a tropical estuary

Fish communities associated with coral reefs worldwide are threatened by overexploitation and other human impacts such as bleaching events that cause habitat degradation. We assessed the fish community on coral reefs on the Caribbean coast of Panama, as well as those associated with mangrove and seagrass habitats, to explore the influences of habitat cover, connectivity and environmental characteristics in sustaining biomass, richness and trophic structure in a degraded tropical ecosystem. Overall, 94 % of all fishes across all habitat types were of small body size (≤11 cm), with communities dominated by fishes that usually live in habitats of low complexity, such as Pomacentridae (damselfishes) and Gobiidae (gobies). Moreover, total fish biomass was very low, small fishes from low trophic levels were over-represented, and top predators were under-represented relative to other Caribbean reefs. For example, herbivorous/omnivorous/detrivorous fishes (trophic level 2-2.7) comprised 37 % of total fish biomass, with the diminutive parrotfish Scarus iseri comprising 72 % of the parrotfish biomass. However, the abundance of sponges and proximity of mangroves were found to be important positive drivers of reef fish richness, biomass and trophic structure on a given reef, presumably by promoting functional processes of ecosystems. The masked goby (Coryphopterus personata) was a strong indicator of reef degradation, apparently benefiting from the reduced density of large predators on local reefs. The damselfish Abudefduf saxatilis was more common on reefs with high sponge cover, and also to proximity to mangroves. Our study suggests that a diverse fish community can persist on degraded coral reefs, and that the availability of habitat forming organisms other than corals, including sponges and mangroves, and their arrangement on the landscape, is critical to the maintenance of functional processes in these ecosystems.

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The importance of sponges and mangroves in supporting fish communities in degraded coral reefs in Caribbean Panama

10.7287/peerj.preprints.3062 ◽

2017 ◽

Author(s):

Janina Seemann ◽

Alexandra Yingst ◽

Rick D Stuart-Smith ◽

Graham J Edgar ◽

Andrew H Altieri

Keyword(s):

Coral Reefs ◽

Fish Community ◽

Trophic Structure ◽

Habitat Degradation ◽

Human Impacts ◽

Small Body ◽

Fish Communities ◽

Trophic Levels ◽

Fish Biomass ◽

Total Fish

Fish communities associated with coral reefs worldwide are threatened by overexploitation and other human impacts such as bleaching events that cause habitat degradation. We assessed the fish community on coral reefs on the Caribbean coast of Panama, as well as those associated with mangrove and seagrass habitats, to explore the influences of habitat cover, connectivity and environmental characteristics in sustaining biomass, richness and trophic structure in a degraded tropical ecosystem. Overall, 94 % of all fishes across all habitat types were of small body size (≤11 cm), with communities dominated by fishes that usually live in habitats of low complexity, such as Pomacentridae (damselfishes) and Gobiidae (gobies). Moreover, total fish biomass was very low, small fishes from low trophic levels were over-represented, and top predators were under-represented relative to other Caribbean reefs. For example, herbivorous/omnivorous/detrivorous fishes (trophic level 2-2.7) comprised 37 % of total fish biomass, with the diminutive parrotfish Scarus iseri comprising 72 % of the parrotfish biomass. However, the abundance of sponges and proximity of mangroves were found to be important positive drivers of reef fish richness, biomass and trophic structure on a given reef, presumably by promoting functional processes of ecosystems. The masked goby (Coryphopterus personata) was a strong indicator of reef degradation, apparently benefiting from the reduced density of large predators on local reefs. The damselfish Abudefduf saxatilis was more common on reefs with high sponge cover, and also to proximity to mangroves. Our study suggests that a diverse fish community can persist on degraded coral reefs, and that the availability of habitat forming organisms other than corals, including sponges and mangroves, and their arrangement on the landscape, is critical to the maintenance of functional processes in these ecosystems.

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Succession in epibenthic communities on artificial reefs associated with marine renewable energy facilities within a tide-swept environment

ICES Journal of Marine Science ◽

10.1093/icesjms/fsaa129 ◽

2020 ◽

Author(s):

Bastien Taormina ◽

Arthur Percheron ◽

Martin P Marzloff ◽

Xavier Caisey ◽

Nolwenn Quillien ◽

...

Keyword(s):

Natural Habitat ◽

Artificial Reef ◽

Tidal Energy ◽

High Energy ◽

Artificial Reefs ◽

Mature Stage ◽

Artificial Structures ◽

Artificial Habitats ◽

Epibenthic Communities

Abstract Although colonization of artificial structures by epibenthic communities is well-documented overall, our understanding of colonization processes is largely limited to low-energy environments. In this study, we monitored epibenthic colonization of different structures associated with a tidal energy test site located in a high-energy hydrodynamic environment. Using four years of image-based underwater surveys, we characterized changes through space and time in the taxonomic composition of epibenthic assemblages colonizing two kinds of artificial structures, as well as the surrounding natural habitat. Our results highlight that ecological successions followed similar trends across the two artificial habitats, but that different habitat-specific communities emerged at the end of our survey. Deployment of these artificial structures resulted in the addition of elevated and stable substrata in an environment where natural hard substrates are unstable and strongly exposed to sediment abrasion. Although epibenthic communities colonizing artificial habitats are unlikely to have reached a mature stage at the end of our survey, these supported structurally complex taxa facilitating an overall increase in local diversity. We were able to quantify how epibenthic communities can significantly vary over time in high-energy coastal environment, and our final survey suggests that the ecological succession was still in progress five years after the deployment of artificial reefs. Thus, maintaining long-term continuous survey of coastal artificial reef habitats will be key to better discriminate between long-term ecological successions and shorter-term variability.

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The consequences of balanced harvesting of fish communities

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2013.2701 ◽

2014 ◽

Vol 281 (1775) ◽

pp. 20132701 ◽

Cited By ~ 84

Author(s):

Nis S. Jacobsen ◽

Henrik Gislason ◽

Ken H. Andersen

Keyword(s):

Fish Community ◽

Trophic Structure ◽

Juvenile Fish ◽

Fish Communities ◽

Maximum Sustainable Yield ◽

Biomass Composition ◽

Forage Fish ◽

Sustainable Yield ◽

Fish Community Structure ◽

Total Maximum

Balanced harvesting, where species or individuals are exploited in accordance with their productivity, has been proposed as a way to minimize the effects of fishing on marine fish communities and ecosystems. This calls for a thorough examination of the consequences balanced harvesting has on fish community structure and yield. We use a size- and trait-based model that resolves individual interactions through competition and predation to compare balanced harvesting with traditional selective harvesting, which protects juvenile fish from fishing. Four different exploitation patterns, generated by combining selective or unselective harvesting with balanced or unbalanced fishing, are compared. We find that unselective balanced fishing, where individuals are exploited in proportion to their productivity, produces a slightly larger total maximum sustainable yield than the other exploitation patterns and, for a given yield, the least change in the relative biomass composition of the fish community. Because fishing reduces competition, predation and cannibalism within the community, the total maximum sustainable yield is achieved at high exploitation rates. The yield from unselective balanced fishing is dominated by small individuals, whereas selective fishing produces a much higher proportion of large individuals in the yield. Although unselective balanced fishing is predicted to produce the highest total maximum sustainable yield and the lowest impact on trophic structure, it is effectively a fishery predominantly targeting small forage fish.

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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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Temporal and spatial variation in adult and juvenile mobile fauna associated with natural and artificial coastal habitats

Marine Biology ◽

10.1007/s00227-021-03823-0 ◽

2021 ◽

Vol 168 (2) ◽

Author(s):

Alice E. Hall ◽

Roger J. H. Herbert ◽

Richard Stafford

Keyword(s):

Dicentrarchus Labrax ◽

Early Summer ◽

Coastal Habitats ◽

Artificial Structures ◽

Artificial Habitats ◽

Mobile Species ◽

Spatial And Seasonal Variation ◽

Black Bream ◽

Temporal And Spatial ◽

Natural Reefs

AbstractCoastal habitats are important for commercially exploited and protected species of fish and larger mobile invertebrates. The addition of artificial structures within the marine environment has the potential to alter the connectivity between habitats and to affect metapopulations of a region. Baited remote underwater videos (BRUV) were used to investigate the spatial and seasonal variation in abundance of adult and juvenile mobile species associated with subtidal natural and artificial habitats within Poole Bay on the south coast of England in 2019. Metrics included the relative maximum abundance (MaxN), number of species seen (S), assemblage structure and size range of fish. Higher values of MaxN and S were recorded on artificial structures in the spring and early summer; however, this pattern was reversed by mid-summer and early autumn when more fish were recorded on the natural reefs. Yet overall differences in MaxN and S between habitats were not significant. Differences in assemblage composition between habitats varied monthly, but this was mostly driven by particular sites. Although most fish observed were juveniles, there were some seasonal differences in the size of fish using natural and artificial sites, especially bib (Trisopterus luscus), black bream (Spondyliosoma cantharus), bass (Dicentrarchus labrax) and pollack (Pollachius pollachius). The artificial habitats in this region appeared to be important in certain months, so temporal studies of this type need to be incorporated within surveys, particularly those in proximity to protected areas.

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Family graveyards form underappreciated local plant diversity hotspots in China's agricultural landscapes

Scientific Reports ◽

10.1038/s41598-020-80362-6 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Cheng Gong ◽

Liangtao Li ◽

Jan C. Axmarcher ◽

Zhenrong Yu ◽

Yunhui Liu

Keyword(s):

Species Richness ◽

Plant Species ◽

Natural Habitat ◽

Plant Species Richness ◽

Agricultural Landscapes ◽

Natural Habitats ◽

Landscape Features ◽

Habitat Islands ◽

Local Plant ◽

Ecological Functioning

AbstractIn the intensively farmed, homogenous agricultural landscape of the North China Plain, family graveyards form distinct cultural landscape features. In addition to their cultural value, these graveyards represent semi-natural habitat islands whose potential roles in biodiversity conservation and ecological functioning has remained poorly understood. In this study, we investigated plant species richness on 199 family graveyards of different ages and sizes. In accordance with biogeography theory, both overall and insect-pollinated plant species richness increased with area and age of graveyards. Even small graveyards show a strong potential for conserving local plant richness, and a mosaic of both large and small family graveyards could play an important role in the conservation of farmland biodiversity and related ecosystem functions. The launch of agri-environmental measures that conserve and create semi-natural habitats, in turn benefitting agricultural biodiversity and ecological functioning, has proven difficult in China due to the shortage of dispensable arable land. Given the great value of family graveyards as semi-natural habitats reflected in our study, we propose to focus preliminary efforts on conserving these landscape features as existing, widespread and culturally important semi-natural habitat islands. This would represent an effective, complementary policy to a subsequent re-establishment of other semi-natural habitats for the conservation of biodiversity and ecological functioning in agricultural landscapes.

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Aspects of the Water, Electrolyte and Carbohydrate Physiology of the Silvereye, Zosterops Lateralis (Aves).

Australian Journal of Zoology ◽

10.1071/zo9830695 ◽

1983 ◽

Vol 31 (5) ◽

pp. 695 ◽

Cited By ~ 11

Author(s):

IJ Rooke ◽

SD Bradshaw ◽

RA Langworthy

Keyword(s):

Natural Habitat ◽

Tritiated Water ◽

Free Water ◽

Laboratory Studies ◽

Turnover Rates ◽

Natural Habitats ◽

Water Influx ◽

Zosterops Lateralis ◽

Total Body ◽

Free Ranging

Total body water content (TBW) and TBW turnover were measured by means of tritiated water (HTO) in free-ranging populations of silvereyes, Zosterops lateralis, near Margaret River, W.A. Birds were studied in their natural habitats during spring and summer, and compared with a vineyard population in summer. In the natural habitat TBW content was found to be 77.6% in spring, which was not significantly different from that measured in summer (78.3%). Birds in vineyards in summer, however, were dehydrated, with a TBW content of 69.4%. Calculated rates of water influx for spring, summer and summer vineyards birds were 1.44,2.20 and 0.65 ml g.day-' respectively. These water turnover rates are much higher than those of any other bird yet studied. Dehydration was marked in the vineyard birds, with a significantly lower TBW content and an average net water loss of 0.63 ml day-'. Laboratory studies showed that silvereyes have a low tolerance to sodium loading. Their tolerance is, however, quite adequate for them to drink the most concentrated free water available to them in the field. Ingestion of concentrated sugar solutions of up to 25% did not provoke an osmotic diuresis and thus cannot account for the dehydration and negative water balance of vineyard birds.

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