scholarly journals Different levels of taxonomic resolution in bioassessment: a case study of oligochaeta in lowland streams

2012 ◽  
Vol 23 (4) ◽  
pp. 412-425 ◽  
Author(s):  
Agustina Cortelezzi ◽  
Laura Cecilia Armendáriz ◽  
María Vanesa López van Oosterom ◽  
Rosana Cepeda ◽  
Alberto Rodrigues Capítulo
Keyword(s):  
Habitat Type ◽  
Environmental Indicators ◽  
High Impact ◽  
Habitat Characteristics ◽  
Taxonomic Resolution ◽  
Contamination Level ◽  
Physical Habitat ◽  
Test Species ◽  
Lowland Streams ◽  
Different Levels

AIM: This study evaluated the use of oligochaetes at different levels of taxonomic resolution as environmental indicators in Argentine lowland streams affected by different land uses. METHODS: Sampling sites were grouped based on the physicochemical and habitat characteristics (low-, moderate-, and high-impact disturbance). Collection of the oligochaetes samples was carried out seasonally in sediment and vegetation habitats. RESULTS: The increases in nutrients and organic matter produced elevated densities of the Oligochaeta, but when the disturbance also involved changes in the physical habitat or enhancements in toxic substances, the abundance decreased significantly to values even lower than those of non-impacted environments. The responses of Naidinae and Tubificinae were similar. The density of the Pristininae decreased with increasing impact, but those of the Enchytraeidae and Rhyacodrilinae increased at the most highly impacted sites. The Opistocystidae were not recorded in high-impact sites. Species richness and diversity (H') were lower in high-impact sites and even lower in sediments. Some species presented no restrictions in the habitat type or with the contamination level: Limnodrilus hoffmeisteri, Dero furcatus, D. digitata, D. pectinata, Pristina longiseta, and P. aequiseta. Moreover, Trieminentia corderoi, Slavina appendiculata, and Aulodrilus pigueti exhibited the highest abundances at low-impact sites and were not registered in high-impact sites. CONCLUSIONS: The Oligochaeta show a relatively wide ecological valence through their extensive number of species. Although lower taxonomic levels can give information about environmental status, test-species' sensitivities to different types and degrees of contamination will be of utmost relevance to the evaluation of ecological quality.

scholarly journals The mangrove flora and their physical habitat characteristics in Bunaken National Park, North Sulawesi, Indonesia

2018 ◽  
Vol 19 (4) ◽  
pp. 1303-1312
Author(s):  
RIGNOLDA DJAMALUDDIN
Keyword(s):  
National Park ◽  
Habitat Characteristics ◽  
Physical Habitat ◽  
Mangrove Forests ◽  
Physical Processes ◽  
Mangrove Species ◽  
Distribution Limit ◽  
North Sulawesi ◽  
Special Notice ◽  
Lumnitzera Racemosa

Djamaluddin R. 2018. The mangrove flora and their physical habitat characteristics in Bunaken National Park, NorthSulawesi, Indonesia. Biodiversitas 19: 1303-1312. The mangrove forests of Bunaken National Park are among the most distinctive andunusual in Southeast Asia because of the species that the forests contain. This study investigated the identity and diversity of mangroveplants as well as physiographic factors and major physical processes of every type of sub-habitats. Seven surveys were conducted tocollect and identify mangrove species of the park. Sub-habitats where specimen was found, aspects related to tidal inundation, nature ofsoil, freshwater influence and topography were observed as well as major physical processes influencing the condition of each subhabitat.The results suggested that the park was floristically rich with at least 27 plant species and they were distributed over tenrecognized sub-habitat types in different composition and diversity. Ceriops zippeliana Blume, Lumnitzera racemosa Willd, Lumnitzeralittorea (Jack) Voigt., Sonneratia ovata Backer, and Camptostemon philippinense (Vidal) Becc. were found in Bunaken National Parkand their presence confirmed the broader distribution limit of these species within Indo-Malesia region. A special notice was for C.philippinense as the distribution limit of this is rarely reported.

3. Sunlight and motion

2018 ◽  
pp. 26-47
Author(s):  
Warwick F. Vincent
Keyword(s):  
Ecosystem Services ◽  
The State ◽  
Slow Waves ◽  
Habitat Characteristics ◽  
Water Transparency ◽  
Lake Ecosystem ◽  
Physical Habitat ◽  
State Of Health ◽  
Temperature Water

Water transparency powerfully indicates the state of health of a lake ecosystem. The water’s turbidity defines the physical habitat characteristics of lakes, strongly influencing their chemistry, biology, and ecosystem services. ‘Sunlight and motion’ explains the methods for measuring water transparency and how the penetration of sunlight into water declines with depth. The different colours, hues, and brightness levels of lakes are due to the materials dissolved and suspended within them. The layering of different temperature water in lakes is also described. This stratification varies greatly with the seasons. Mixing of the waters is mainly due to slow waves at and just below the surface as well as deeper currents.

scholarly journals Analysis for Underwater Sound on Natural River Habitat

2018 ◽  
Vol 40 ◽  
pp. 02047
Author(s):  
Jung-Eun Gu ◽  
Sang Hwa Jung ◽  
Joongu Kang ◽  
Hyoseop Woo
Keyword(s):  
Underwater Acoustics ◽  
Fish Habitat ◽  
Habitat Type ◽  
High Water ◽  
Physical Structure ◽  
Physical Habitat ◽  
Hydraulic Characteristics ◽  
Underwater Sound ◽  
Underwater Acoustic ◽  
Sound Environment

A riffle-pool structure is a representative physical structure of bed in rivers. The change in the physical parameter of the habitat could lead to changes in the sound environment of rivers, which are expressed by underwater acoustics. This change in underwater sound affects fish habitat. In this study, the changes of underwater acoustics were analyzed according to the change of pool-riffle sequence in a natural river. And the correlation between underwater acoustics and hydraulic characteristics was investigated. The survey for underwater acoustics was performed in the Namdae stream where is in Gangwon province. This stream belongs to the Han River basin and the river length is 39.01 km and the catchment area is 127.56 km2. The Namdae stream is a river that accounts for more than 70% of salmon returning to South Korea. The spawning salmon will return to this area around November after growing in the Bering Sea. It is important to manage the fish habitat in this river so there is a lot of research on the enhancement of fish habitat. Hydraulic characteristics were changed by the river bed structure. In this study, we investigated the relationship between underwater acoustic characteristics and hydraulic factors such as riverbed material, flow rate and water depth of each habitat type at 12 sites. The characteristics of underwater acoustic differed relative to different hydraulic factors of the two habitats, which is riffle and pool. The sound pressure level of riffles was relatively higher than that of the pools due to bed materials, shallow depth and high water velocity of riffles. In the future, it is considered that the underwater sound can be utilized as a parameter to evaluate the physical habitat environment of the river.

scholarly journals Molecular variation among virulent and avirulent strains of the quarantine nematode Bursaphelenchus xylophilus

2020 ◽  
Author(s):  
Anna Filipiak ◽  
Tadeusz Malewski ◽  
Ewa Matczyńska ◽  
Marek Tomalak
Keyword(s):  
Molecular Level ◽  
Pine Wilt Disease ◽  
Bursaphelenchus Xylophilus ◽  
Wilt Disease ◽  
High Impact ◽  
Genomic Variation ◽  
Economic Losses ◽  
Pathogenesis Related ◽  
Nematode Virulence ◽  
Different Levels

Abstract Bursaphelenchus xylophilus is an emerging pathogenic nematode that is responsible for a devastating epidemic of pine wilt disease worldwide, causing severe ecological damage and economic losses to forestry. Two forms of this nematode have been reported, i.e., with strong and weak virulence, commonly referred as virulent and avirulent strains. However, the pathogenicity-related genes of B. xylophilus are not sufficiently characterized. In this study, to find pathogenesis related genes we re-sequenced and compared genomes of two virulent and two avirulent populations. We identified genes affected by genomic variation, and functional annotation of those genes indicated that some of them might play potential roles in pathogenesis. The performed analysis showed that both avirulent populations differed from the virulent ones by 1576 genes with high impact variants. Demonstration of genetic differences between virulent and avirulent strains will provide effective methods to distinguish these two nematode virulence forms at the molecular level. The reported results provide basic information that can facilitate development of a better diagnosis for B. xylophilus isolates/strains which present different levels of virulence and better understanding of the molecular mechanism involved in the development of the PWD.

From continua to patches: examining stream community structure over large environmental gradients

2002 ◽  
Vol 59 (8) ◽  
pp. 1404-1417 ◽  
Author(s):  
Kristopher K Wright ◽  
Judith L Li
Keyword(s):  
Conceptual Framework ◽  
Algal Biomass ◽  
Environmental Gradients ◽  
Spatial Scales ◽  
Habitat Characteristics ◽  
Physical Habitat ◽  
Macroinvertebrate Communities ◽  
Order Stream ◽  
Longitudinal Gradients ◽  
Individual Variables

We present an approach that integrates a conceptual framework with multivariate ordination techniques and traditional parametric analyses to examine biotic and abiotic gradients in stream ecosystems. Ordinations were used to examine multivariate patterns along an environmental gradient, with individual variables used to interpret those patterns across spatial scales. The conceptual framework provides a consistent context to compare community distributions and consequently allows for hypothesis testing using ordinations. To illustrate the approach, we examined the physical template, fish and benthic macroinvertebrate communities, and algal biomass and production along a 1st- through 5th-order stream gradient in eastern Oregon. We hypothesized that longitudinal distributions of physical habitat characteristics, fishes, macroinvertebrates, and periphyton would reflect highly variable, discontinuous gradients. Multivariate patterns were determined by rotating nonparametric ordinations to a common set of variables and comparing them to conceptual models of (i) an ideal continuum, (ii) a random distribution, and (iii) discrete patches. Physical habitat and fishes reflected strong longitudinal gradients, macroinvertebrates were the most patchy, and algal biomass and production were highly variable. Distributions of individual variables from site and stream-order perspectives revealed how different factors, potentially influencing stream communities, may be continuous or patchy depending on spatial scale.

Macrophytes, epipelic biofilm, and invertebrates as biotic indicators of physical habitat degradation of lowland streams (Argentina)

2012 ◽  
Vol 185 (7) ◽  
pp. 5801-5815 ◽  
Author(s):  
Agustina Cortelezzi ◽  
María Victoria Sierra ◽  
Nora Gómez ◽  
Claudia Marinelli ◽  
Alberto Rodrigues Capítulo
Keyword(s):  
Habitat Degradation ◽  
Physical Habitat ◽  
Lowland Streams

scholarly journals A standardized, extensible framework for optimizing classification improves marker-gene taxonomic assignments

2015 ◽  
Author(s):  
Nicholas A Bokulich ◽  
Jai Ram Rideout ◽  
Evguenia Kopylova ◽  
Evan Bolyen ◽  
Jessica Patnode ◽  
...  
Keyword(s):  
Marker Gene ◽  
Amplicon Sequencing ◽  
Evaluation Framework ◽  
Taxonomic Resolution ◽  
Marker Genes ◽  
Classification Methods ◽  
New Methods ◽  
Taxonomic Assignments ◽  
Different Levels

Background: Taxonomic classification of marker-gene (i.e., amplicon) sequences represents an important step for molecular identification of microorganisms. Results: We present three advances in our ability to assign and interpret taxonomic classifications of short marker gene sequences: two new methods for taxonomy assignment, which reduce runtime up to two-fold and achieve high precision genus-level assignments; an evaluation of classification methods that highlights differences in performance with different marker genes and at different levels of taxonomic resolution; and an extensible framework for evaluating and optimizing new classification methods, which we hope will serve as a model for standardized and reproducible bioinformatics methods evaluations. Conclusions: Our new methods are accessible in QIIME 1.9.0, and our evaluation framework will support ongoing optimization of classification methods to complement rapidly evolving short-amplicon sequencing and bioinformatics technologies. Static versions of all of the analysis notebooks generated with this framework, which contain all code and analysis results, can be viewed at http://bit.ly/srta-010.

scholarly journals Diet shifts and delayed piscivory specialisation during the ontogenesis of the largemouth bass Micropterus salmoides (Lacepede, 1802) in the Nakdong River and Upo Wetlands, South Korea

2016 ◽  
Vol 63 (4) ◽  
Author(s):  
Hyunbin Jo ◽  
Ju-Duk Yoon ◽  
Jeong-Hui Kim ◽  
Kwang-Seuk Jeong ◽  
Yuno Do ◽  
...  
Keyword(s):  
South Korea ◽  
Largemouth Bass ◽  
Prey Selection ◽  
Micropterus Salmoides ◽  
Habitat Type ◽  
Habitat Characteristics ◽  
Diet Shift ◽  
Ontogenetic Changes ◽  
Nakdong River ◽  
Prey Items

In this study, we examined the ontogenetic changes in prey selection pattern of largemouth bass Micropterus salmoides (Lacepede, 1802) in accordance with habitat type. The stomach contents of largemouth bass were analysed with respect to predator size classes for two different habitats (Nakdong River main channel and the Upo Wetlands tributary) in South Korea, that differed in the diversity of potential prey items. The diversity (H′) of invertebrate diet items in stomach of largemouth bass was found significantly different between the study sites. Small large mouth bass (<100 mm) preferred to consume decapods and mayflies in the river and wet land systems respectively. Fishes >100 mm in the river and >200 mm in the wet land system preferred fish as their prey. Results demonstrated variations in composition of prey items as influenced by habitat characteristics as well as habitat use type, contributed to the delayed ontogenetic diet shift in the largemouth bass population.

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