scholarly journals Diversity Patterns of Protists are Highly Affected by Methods Disentangling Inter-specific Variants: A Case Study in Oligotrich (s.l.) Ciliates

2021 ◽  
Author(s):  
Jiahui Xu ◽  
Jianlin Han ◽  
Hua Su ◽  
Changyu Zhu ◽  
Zijing Quan ◽  
...  
Keyword(s):  
Species Richness ◽  
Beta Diversity ◽  
High Throughput Sequencing ◽  
River Estuary ◽  
Distribution Patterns ◽  
Pearl River Estuary ◽  
Diversity Pattern ◽  
Diversity Patterns ◽  
Field Samples ◽  
Environmental Sequences

Abstract An enormous amount of environmental sequences produced by high-throughput sequencing (HTS) is popular for inferring diversity and distribution patterns of protists, which are widely distributed and playing important roles in energy flux and nutrient cycling. However, study testing whether methods disentangling inter-specific variants affect the diversity and distribution patterns of protists using field samples is insufficient. Using oligotrich (s.l.) ciliates, one group of abundant and dominate planktonic protists, in field samples as an example, the present study indicates that DADA2 performs better than UCLUST and UPARSE for inferring diversity patterns of oligotrich (s.l.) ciliates in Pearl River Estuary and surrounding regions. UPARSE, as an OTU-construction method might underestimate species richness and produce less reliable beta diversity pattern than DADA2. UCLUST with 97% and 99% clustering thresholds overestimate species richness, and the beta diversity pattern inferred by the former one is unreasonable. Salinity is shown to be one of the key factors responsible for variations in community distribution of ciliates, but infrequent marine-freshwater transitions occurred during evolutionary terms of this group.

scholarly journals Species richness and beta diversity patterns of multiple taxa along an elevational gradient in pastured grasslands in the European Alps

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Veronika Fontana ◽  
Elia Guariento ◽  
Andreas Hilpold ◽  
Georg Niedrist ◽  
Michael Steinwandter ◽  
...  
Keyword(s):  
Species Richness ◽  
Beta Diversity ◽  
Elevational Gradient ◽  
European Alps ◽  
Diversity Patterns

scholarly journals From Forest Soil to the Canopy: Increased Habitat Diversity Does Not Increase Species Richness of Cercozoa and Oomycota in Tree Canopies

2020 ◽  
Vol 11 ◽  
Author(s):  
Robin-Tobias Jauss ◽  
Susanne Walden ◽  
Anna Maria Fiore-Donno ◽  
Kenneth Dumack ◽  
Stefan Schaffer ◽  
...  
Keyword(s):  
Species Richness ◽  
Beta Diversity ◽  
High Throughput Sequencing ◽  
Habitat Diversity ◽  
Specific Primers ◽  
Operational Taxonomic Units ◽  
Microbial Eukaryotes ◽  
Tree Canopies ◽  
Species Performance ◽  
Factor Governing

Tree canopies provide habitats for diverse and until now, still poorly characterized communities of microbial eukaryotes. One of the most general patterns in community ecology is the increase in species richness with increasing habitat diversity. Thus, environmental heterogeneity of tree canopies should be an important factor governing community structure and diversity in this subsystem of forest ecosystems. Nevertheless, it is unknown if similar patterns are reflected at the microbial scale within unicellular eukaryotes (protists). In this study, high-throughput sequencing of two prominent protistan taxa, Cercozoa (Rhizaria) and Oomycota (Stramenopiles), was performed. Group specific primers were used to comprehensively analyze their diversity in various microhabitats of a floodplain forest from the forest floor to the canopy region. Beta diversity indicated highly dissimilar protistan communities in the investigated microhabitats. However, the majority of operational taxonomic units (OTUs) was present in all samples, and therefore differences in beta diversity were mainly related to species performance (i.e., relative abundance). Accordingly, habitat diversity strongly favored distinct protistan taxa in terms of abundance, but due to their almost ubiquitous distribution the effect of species richness on community composition was negligible.

Spatial patterns of species richness and taxonomic composition of polychaetes along the Baja California Peninsula, Eastern Pacific

2017 ◽  
Vol 97 (5) ◽  
pp. 1037-1049 ◽  
Author(s):  
Pablo Hernández-Alcántara ◽  
Diana Melissa Cuéllar-Mercado ◽  
Adriana Barbosa-López ◽  
Vivianne Solís-Weiss
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Beta Diversity ◽  
Baja California ◽  
Baja California Peninsula ◽  
Distribution Data ◽  
Diversity Pattern ◽  
Faunal Assemblages ◽  
Distribution Ranges ◽  
Local Sampling

Spatial variations of polychaetes along the Baja California Peninsula continental shelf were analysed in two ways: (1) by evaluating the species richness and defining the faunal assemblages from local sampling, and (2) by characterizing the latitudinal variation of beta-diversity based on the distribution of all polychaetes reported up to now. Twenty-seven stations from three oceanographic expeditions were sampled, and 2858 individuals from 38 families and 231 species were identified. Polychaetes were abundant (mean = 37.5 ind 0.1 m−2) and diversified (mean = 15 species station−1). Differences in species composition defined seven faunal assemblages, but their number of species did not show significant latitudinal changes. The beta-diversity analysis was based on distribution data of 730 species from 47 families. The presence of a group of islands in the middle Gulf could have a negative effect on the species distribution, since the lowest values of βT-diversity (0.39) were found in the northern Gulf, but their species were different from those recorded in the central region. The wide variation in βT-diversity (0.5–0.87) showed latitudinal changes in the species composition, mainly in the Gulf mouth (0.86–0.87), which indicated that the fauna inside the Gulf was different from that inhabiting the Pacific coasts. The ICE and Chao2 estimators showed that the polychaetes in the study area are relatively well known (>80%), and that most species (415) have small distribution ranges. The effects of these infrequent species were similar at each latitudinal band, which suggested that the observed βT-diversity pattern could represent a suitable estimation.

scholarly journals Contrasting multitaxon responses to climate change in Mediterranean mountains

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Luca Di Nuzzo ◽  
Chiara Vallese ◽  
Renato Benesperi ◽  
Paolo Giordani ◽  
Alessandro Chiarucci ◽  
...  
Keyword(s):  
Climate Change ◽  
Species Richness ◽  
Functional Traits ◽  
Beta Diversity ◽  
Vascular Plants ◽  
Climatic Factors ◽  
Species Traits ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Diversity Patterns

AbstractWe explored the influence of climatic factors on diversity patterns of multiple taxa (lichens, bryophytes, and vascular plants) along a steep elevational gradient to predict communities’ dynamics under future climate change scenarios in Mediterranean regions. We analysed (1) species richness patterns in terms of heat-adapted, intermediate, and cold-adapted species; (2) pairwise beta-diversity patterns, also accounting for its two different components, species replacement and richness difference; (3) the influence of climatic variables on species functional traits. Species richness is influenced by different factors between three taxonomic groups, while beta diversity differs mainly between plants and cryptogams. Functional traits are influenced by different factors in each taxonomic group. On the basis of our observations, poikilohydric cryptogams could be more impacted by climate change than vascular plants. However, contrasting species-climate and traits-climate relationships were also found between lichens and bryophytes suggesting that each group may be sensitive to different components of climate change. Our study supports the usefulness of a multi-taxon approach coupled with a species traits analysis to better unravel the response of terrestrial communities to climate change. This would be especially relevant for lichens and bryophytes, whose response to climate change is still poorly explored.

scholarly journals A Small-Scale Analysis of Elevational Species Richness and Beta Diversity Patterns of Arthropods on an Oceanic Island (Terceira, Azores)

Insects ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 936
Author(s):  
Jan Peter Reinier de Vries ◽  
Emiel van Loon ◽  
Paulo A. V. Borges
Keyword(s):  
Species Richness ◽  
Introduced Species ◽  
Beta Diversity ◽  
Climatic Factors ◽  
Elevation Gradient ◽  
Small Scale ◽  
Native Forest ◽  
Species Replacement ◽  
Diversity Patterns ◽  
Total Species Richness

We present an analysis of arthropod diversity patterns in native forest communities along the small elevation gradient (0–1021 m a.s.l.) of Terceira island, Azores (Portugal). We analysed (1) how the alpha diversity of Azorean arthropods responds to increasing elevation and (2) differs between endemic, native non-endemic and introduced (alien) species, and (3) the contributions of species replacement and richness difference to beta diversity. Arthropods were sampled using SLAM traps between 2014 and 2018. We analysed species richness indicators, the Hill series and beta diversity partitioning (species replacement and species richness differences). Selected orders (Araneae, Coleoptera, Hemiptera and Psocoptera) and endemic, native non-endemic and introduced species were analysed separately. Total species richness shows a monotonic decrease with elevation for all species and Coleoptera and Psocoptera, but peaks at mid-high elevation for Araneae and endemic species. Introduced species richness decreases strongly with elevation especially. These patterns are most likely driven by climatic factors but also influenced by human disturbance. Beta diversity is, for most groups, the main component of total (gamma) diversity along the gradient but shows no relation with elevation. It results from a combined effect of richness decrease with elevation and species replacement in groups with many narrow-ranged species.

Spatiotemporal variations of total suspended matter (TSM) in the Pearl River estuary using MERIS full-resolution (FR) level-2 TSM product

2019 ◽  
Vol 70 (8) ◽  
pp. 1065
Author(s):  
Feng Gao ◽  
Yunpeng Wang ◽  
Xinyi Hu ◽  
Chao Xu ◽  
Ned Horning
Keyword(s):  
River Estuary ◽  
Distribution Patterns ◽  
Pearl River Estuary ◽  
Total Suspended Matter ◽  
Spatial And Temporal Variation ◽  
Pearl River ◽  
The Pearl River Estuary ◽  
Full Resolution ◽  
The Pearl River ◽  
Level 2

In this study, we first use self-organising map (SOM) and medium-resolution imaging spectrometer (MERIS) full-resolution (FR) level-2 total suspended matter (TSM) product to identify spatial-distribution patterns of TSM concentration in the Pearl River estuary. Second, the spatial and temporal variation of TSM concentration in the Pearl River estuary was investigated using 9-year (2003–2011) MERIS FR level-2 TSM products. The spatial-distribution patterns of TSM concentration identified by SOM in the Pearl River estuary showed that there are high values in west and north and low values in east and south. On the basis of the analysis of the sample points randomly extracted from the Pearl River estuary, the results showed that the spatial variation of TSM in eight gates varied greatly, and the Lingdingyang Bay from Humen to offshore waters (i.e. Xitan, Zhongtan and Dongtan) presents a decreasing trend. Moreover, extreme climate events (e.g. EI Niño and La Niña) may have a great effect on spatial and temporal variation of TSM concentration in the Pearl River estuary. These results could provide a new insight for a better understanding of the dynamics of TSM concentration in the Pearl River estuary and the effect of soil- and water-conservation measures in the upstream of Pearl River.

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