scholarly journals Community structure and diversity of demersal fish assemblages: the role of fishery

2004 ◽  
Vol 68 (S1) ◽  
pp. 215-226 ◽  
Author(s):  
Mary Labropoulou ◽  
Costas Papaconstantinou
Keyword(s):  
Community Structure ◽  
Fish Assemblages ◽  
Demersal Fish

Rockpool ichthyofauna of Amazon coastal zone: spatial and environmental effects on species distribution

2017 ◽  
Vol 68 (6) ◽  
pp. 1137 ◽  
Author(s):  
Tiago Octavio Begot ◽  
Bruno Eleres Soares ◽  
Leandro Juen ◽  
Luciano Fogaça de Assis Montag
Keyword(s):  
Community Structure ◽  
Coastal Zone ◽  
Intertidal Zone ◽  
Fish Assemblages ◽  
Sandy Beaches ◽  
Tidal Range ◽  
Spatial Variables ◽  
Β Diversity ◽  
Principal Factors

The present study analysed the effects of environmental and spatial variables on the structure of fish communities inhabiting rockpools in the Amazon coastal zone to test the hypothesis that environmental characteristics and spatial distribution are the principal factors responsible for community structure. In all, 80 pools were sampled, 40 in the rainy season and 40 in the dry season. The pools were located on five sandy beaches of the Amazon coast. In all, 1303 fish were collected, representing 20 taxa distributed in nine orders and 14 families. The abundance and occurrence of different taxa varied considerably, as did β diversity, ranging from identical to completely different communities. Differences were found in taxa abundance between seasons (rainy and dry) and beach locality. However, for species richness, only differences between seasons were found, showing the effects of spatial and environmental variation in the structure of fish assemblages. This corroborates both spatial and environmental hypotheses of community structure, and reinforces the role of the extreme dynamic conditions, such as tidal range and influence of the rivers that flow into this estuary, in the intertidal zone fish on the Amazon coast.

Dissolved oxygen and temperature best predict deep-sea fish community structure in the Gulf of California with climate change implications

2020 ◽  
Vol 637 ◽  
pp. 159-180
Author(s):  
ND Gallo ◽  
M Beckwith ◽  
CL Wei ◽  
LA Levin ◽  
L Kuhnz ◽  
...  
Keyword(s):  
Climate Change ◽  
Community Structure ◽  
Community Composition ◽  
Environmental Conditions ◽  
Deep Sea ◽  
Gulf Of California ◽  
Fish Community ◽  
Demersal Fish ◽  
Fish Community Structure ◽  
Explained Variance

Natural gradient systems can be used to examine the vulnerability of deep-sea communities to climate change. The Gulf of California presents an ideal system for examining relationships between faunal patterns and environmental conditions of deep-sea communities because deep-sea conditions change from warm and oxygen-rich in the north to cold and severely hypoxic in the south. The Monterey Bay Aquarium Research Institute (MBARI) remotely operated vehicle (ROV) ‘Doc Ricketts’ was used to conduct seafloor video transects at depths of ~200-1400 m in the northern, central, and southern Gulf. The community composition, density, and diversity of demersal fish assemblages were compared to environmental conditions. We tested the hypothesis that climate-relevant variables (temperature, oxygen, and primary production) have more explanatory power than static variables (latitude, depth, and benthic substrate) in explaining variation in fish community structure. Temperature best explained variance in density, while oxygen best explained variance in diversity and community composition. Both density and diversity declined with decreasing oxygen, but diversity declined at a higher oxygen threshold (~7 µmol kg-1). Remarkably, high-density fish communities were observed living under suboxic conditions (<5 µmol kg-1). Using an Earth systems global climate model forced under an RCP8.5 scenario, we found that by 2081-2100, the entire Gulf of California seafloor is expected to experience a mean temperature increase of 1.08 ± 1.07°C and modest deoxygenation. The projected changes in temperature and oxygen are expected to be accompanied by reduced diversity and related changes in deep-sea demersal fish communities.

An inter-dependence of flood and drought: disentangling amphibian beta diversity in seasonal floodplains

2017 ◽  
Vol 68 (11) ◽  
pp. 2115 ◽  
Author(s):  
Leonardo F. B. Moreira ◽  
Tainá F. Dorado-Rodrigues ◽  
Vanda L. Ferreira ◽  
Christine Strüssmann
Keyword(s):  
Community Structure ◽  
Environmental Factors ◽  
Quantitative Data ◽  
Explanatory Variable ◽  
Biotic Interactions ◽  
Ecological Role ◽  
Β Diversity ◽  
Amphibian Community ◽  
Dry Seasons

Species composition in floodplains is often affected by different structuring factors. Although floods play a key ecological role, habitat selection in the dry periods may blur patterns of biodiversity distribution. Here, we employed a partitioning framework to investigate the contribution of turnover and nestedness to β-diversity patterns in non-arboreal amphibians from southern Pantanal ecoregion. We investigated whether components of β-diversity change by spatial and environmental factors. We sampled grasslands and dense arboreal savannas distributed in 12 sampling sites across rainy and dry seasons, and analysed species dissimilarities using quantitative data. In the savannas, both turnover and nestedness contributed similarly to β diversity. However, we found that β diversity is driven essentially by turnover, in the grasslands. In the rainy season, balanced variation in abundance was more related to altitude and factors that induce spatial patterns, whereas dissimilarities were not related to any explanatory variable during dry season. In the Pantanal ecoregion, amphibian assemblages are influenced by a variety of seasonal constraints on terrestrial movements and biotic interactions. Our findings highlighted the role of guild-specific patterns and indicated that mass effects are important mechanisms creating amphibian community structure in the Pantanal.

scholarly journals Stochastic Assembly Leads to Alternative Communities with Distinct Functions in a Bioreactor Microbial Community

mBio ◽  
2013 ◽  
Vol 4 (2) ◽  
Author(s):  
Jizhong Zhou ◽  
Wenzong Liu ◽  
Ye Deng ◽  
Yi-Huei Jiang ◽  
Kai Xue ◽  
...  
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Diversity ◽  
Microbial Community Structure ◽  
Community Assembly ◽  
Ecosystem Functioning ◽  
Dominant Role ◽  
Microbial Biodiversity ◽  
Stochastic Assembly

ABSTRACTThe processes and mechanisms of community assembly and its relationships to community functioning are central issues in ecology. Both deterministic and stochastic factors play important roles in shaping community composition and structure, but the connection between community assembly and ecosystem functioning remains elusive, especially in microbial communities. Here, we used microbial electrolysis cell reactors as a model system to examine the roles of stochastic assembly in determining microbial community structure and functions. Under identical environmental conditions with the same source community, ecological drift (i.e., initial stochastic colonization) and subsequent biotic interactions created dramatically different communities with little overlap among 14 identical reactors, indicating that stochastic assembly played dominant roles in determining microbial community structure. Neutral community modeling analysis revealed that deterministic factors also played significant roles in shaping microbial community structure in these reactors. Most importantly, the newly formed communities differed substantially in community functions (e.g., H2production), which showed strong linkages to community structure. This study is the first to demonstrate that stochastic assembly plays a dominant role in determining not only community structure but also ecosystem functions. Elucidating the links among community assembly, biodiversity, and ecosystem functioning is critical to understanding ecosystem functioning, biodiversity preservation, and ecosystem management.IMPORTANCEMicroorganisms are the most diverse group of life known on earth. Although it is well documented that microbial natural biodiversity is extremely high, it is not clear why such high diversity is generated and maintained. Numerous studies have established the roles of niche-based deterministic factors (e.g., pH, temperature, and salt) in shaping microbial biodiversity, the importance of stochastic processes in generating microbial biodiversity is rarely appreciated. Moreover, while microorganisms mediate many ecosystem processes, the relationship between microbial diversity and ecosystem functioning remains largely elusive. Using a well-controlled laboratory system, this study provides empirical support for the dominant role of stochastic assembly in creating variations of microbial diversity and the first explicit evidence for the critical role of community assembly in influencing ecosystem functioning. The results presented in this study represent important contributions to the understanding of the mechanisms, especially stochastic processes, involved in shaping microbial biodiversity.

Demersal fish assemblages on seamounts exploited by fishing in the Azores (NE Atlantic)

2020 ◽  
Author(s):  
Régis Santos ◽  
Wendell Medeiros‐Leal ◽  
Ana Novoa‐Pabon ◽  
Hélder Silva ◽  
Mário Pinho
Keyword(s):  
Fish Assemblages ◽  
Demersal Fish ◽  
Ne Atlantic

scholarly journals A review on macrobenthic trophic relationships along subtropical sandy shores in southernmost Brazil

2014 ◽  
Vol 14 (3) ◽  
Author(s):  
Raphael Mathias Pinotti ◽  
Diogo Marroni Minasi ◽  
Leonir André Colling ◽  
Carlos Emílio Bemvenuti
Keyword(s):  
Surf Zone ◽  
Fish Assemblages ◽  
Trophic Levels ◽  
Trophic Relationships ◽  
Intermediate Type ◽  
Sandy Shores ◽  
Macrobenthic Assemblages ◽  
High Species Richness ◽  
Asterionellopsis Glacialis

Main trophic relationships that occur along the exposed sandy shores in southernmost Brazil (∼33° S) are established taking into account several biological compartments operating at morphodynamically distinct environments. Beaches are predominantly of the intermediate type but some stretches of coastline are truly dissipative (Cassino Beach) or tending-to-reflective (Concheiros Beach), presenting thus diverse biological compartments and inhabitant macrobenthic assemblages. Dense concentrations of the surf-zone diatom Asterionellopsis glacialis are responsible - at least for the intermediate shorelines - for the most year-round primary production, sustaining several consumers up to tertiary level. Among them, bivalves Amarilladesma mactroides, Donax hanleyanus and the hippid crabEmerita brasiliensis can account for more than 95% of all the surf-zone secondary production, in addition to the elevated biomass of the suspension-feeder polychaete Spio gaucha and the scavenger isopod Excirolana armata. Crabs, whelks, carnivorous polychaetes, seabirds and surf-zone fishes may also be present and occupy superior trophic levels depending on the beach morphodynamics. Based on the high species richness, abundance and the role of macrobenthic fauna in transferring matter and energy to seabirds and the surf-zone fish assemblages, we address this important issue on the Southwestern Atlantic ecology. Conservation efforts should be implemented for the southernmost Brazilian sandy shores, at least for those non urbanized areas.

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