scholarly journals Expected species richness in the genus Psechrus in Laos (Araneae: Psechridae)

2010 ◽  
Vol 117 ◽  
pp. 57-75 ◽  
Author(s):  
Steffen Bayer ◽  
Peter Jäger
Keyword(s):  
Species Richness ◽  
Expected Species Richness

Distribution of moss-inhabiting diatoms along an altitudinal gradient at sub-Antarctic Îles Kerguelen

2007 ◽  
Vol 19 (1) ◽  
pp. 17-24 ◽  
Author(s):  
Niek J.M. Gremmen ◽  
Bart van de Vijver ◽  
Yves Frenot ◽  
Marc Lebouvier
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Altitudinal Gradient ◽  
Cross Validation ◽  
Strong Relationship ◽  
Distribution Patterns ◽  
Common Species ◽  
Important Variable ◽  
Diatom Species ◽  
Expected Species Richness

Altitudinal gradients provide excellent opportunities to study relationships between species distribution and climatic variables. We studied the species composition of 39 samples of moss-inhabiting diatoms, collected at 50 m intervals from 100–650 m above sea level. The samples contained a total of 130 diatom species, of which 51 occurred in 10 or more samples. Altitude appeared to be the most important variable explaining variation in species composition. Of the 51 common species, 33 showed a significant relationship with altitude. Although the majority of the latter declined with increasing altitude, for nine species the probability of occurrence first increased with increasing elevation, but decreased again at higher altitudes, and four species increased systematically with elevation. As a result, expected species richness per sample decreased from an estimated 43 at 100 m to 25 species per sample at 650 m. Diatom distribution patterns proved to be suitable predictors of the altitudinal position of sample sites. Cross-validation yielded a strong relationship between predicted and observed altitudes.

scholarly journals The presence of lateral photophores correlates with increased speciation in deep-sea bioluminescent sharks

2015 ◽  
Vol 2 (7) ◽  
pp. 150219 ◽  
Author(s):  
Julien M. Claes ◽  
Dan-Eric Nilsson ◽  
Jérôme Mallefet ◽  
Nicolas Straube
Keyword(s):  
Species Richness ◽  
Reproductive Isolation ◽  
Deep Sea ◽  
Functional Significance ◽  
Phylogenetic Analyses ◽  
Medium Range ◽  
Molecular Phylogenetic ◽  
Intraspecific Communication ◽  
Expected Species Richness

The vast majority of species within the lanternshark genus Etmopterus harbour complex luminescent markings on their flanks, whose functional significance has long remained obscure. Recent studies, however, suggest these enigmatic photophore aggregations to play a role in intraspecific communication. Using visual modelling based on in vivo luminescence measurements from a common lanternshark species, we show that etmopterid flank markings can potentially work as a medium range signal for intraspecific detection/recognition. In addition, using molecular phylogenetic analyses, we demonstrate that the Etmopterus clade exhibits a greater than expected species richness given its age. This is not the case for other bioluminescent shark clades with no (or only few) species with flank markings. Our results therefore suggest that etmopterid flank markings may provide a way for reproductive isolation and hence may have facilitated speciation in the deep-sea.

scholarly journals Faunistic analysis of the species of Anastrepha Schiner (Diptera: Tephritidae) in three municipalities of the state of Roraima, Brazil

2012 ◽  
Vol 72 (4) ◽  
pp. 813-819 ◽  
Author(s):  
AL. Marsaro Júnior ◽  
DB. Nascimento ◽  
B. Ronchi-Teles ◽  
R. Adaime
Keyword(s):  
Species Richness ◽  
Diversity Index ◽  
The State ◽  
Sampling Effort ◽  
Predominant Species ◽  
Moderate Growth ◽  
Wiener Diversity Index ◽  
First Time ◽  
Cumulative Curves ◽  
Expected Species Richness

The purpose of this work was to describe the population patterns of Anastrepha in three municipalities of the state of Roraima, Brazil, via faunistic analysis. Weekly collections were performed from January through December 2008, using McPhail traps containing 5% hydrolysed protein, in domestic orchards in the municipalities of Boa Vista, Bonfim and Pacaraima. We captured 301 females of Anastrepha in Boa Vista, 212 in Bonfim, and 167 in Pacaraima. Boa Vista presented the highest species richness (S = 10) and Pacaraima the lowest (S = 4). Anastrepha striata was the predominant species in Boa Vista (47.18%) and Pacaraima (65.87%), whereas A. obliqua predominated in Bonfim (46.23%). Boa Vista presented the highest Shannon-Wiener diversity index (H' = 1.19) and Margalef index (α = 1.58), and Bonfim presented the highest Pielou's evenness index (J' = 0.69). In Pacaraima the cumulative curves reached stability, confirming that the observed and expected species richness were the same. In the other two municipalities, the curves showed a moderate growth, suggesting that the sampling effort was not sufficient to produce an accurate depiction of species richness. In this study, Anastrepha zernyi is reported for the first time in Roraima.

scholarly journals Lizards from central Jatapú River, Amazonas, Brazil

Check List ◽  
2014 ◽  
Vol 10 (1) ◽  
pp. 46 ◽  
Author(s):  
Deyla Paula de Oliveira ◽  
Sergio Marques Souza ◽  
Luciana Frazão ◽  
Alexandre Pinheiro de Almeida ◽  
Tomas Hrbek
Keyword(s):  
Species Richness ◽  
Sampling Methods ◽  
Geographic Distance ◽  
Present Species ◽  
Guiana Shield ◽  
Pitfall Traps ◽  
Lizard Species ◽  
Species List ◽  
Expected Species Richness ◽  
Faunal Similarity

The present study reports an inventory of lizard species from a region at the central Jatapú River located in the state of Amazonas, Brazil. The lizard fauna was surveyed using three sampling methods: diurnal and nocturnal visual search, pitfall traps with drift fences, and incidental collections. We recorded 24 lizard species belonging to 18 genera and eight families. Non-parametric estimators of richness (Bootstrap, Chao 2, Jackknife 1, Ace) were used to estimate the percentage of total richness sampled. Expected species richness varied from 27 species estimated via Bootstrap to 30 species with Jackknife 1. The composition of the lizard fauna encountered in the rio Jatapú plot was compared with seven other published surveys carried out in the region of the Brazilian Guiana Shield. The composition of the Jatapú lizard fauna was most similar to FLOTA Faro (84%) and least similar to ESEC Grão-Pará Center (66%). There was no association between faunal similarity and geographic distance. The present species list contributes to our knowledge of lizards of the southern portion of the Guiana Shield in Brazil.

Dominance determines fish community biomass in a temperate seagrass ecosystem

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.

Functional evenness of bird communities varies along the elevational gradient in Europe: Conservation implications

2019 ◽  
Author(s):  
Federico Morelli ◽  
Yanina
Keyword(s):  
Species Richness ◽  
Elevation Gradient ◽  
Bird Species ◽  
Elevational Gradient ◽  
Negative Association ◽  
Bird Communities ◽  
Breeding Bird ◽  
Bird Species Richness ◽  
Large Spatial Scale ◽  
Functional Evenness

ContextThe negative association between elevation and species richness is a well-recognized pattern in macro-ecology. ObjectivesThe aim of this study was to investigate changes in functional evenness of breeding bird communities along an elevation gradient in Europe. MethodsUsing the bird data from the EBCC Atlas of European Breeding Birds we estimated an index of functional evenness which can be assumed as a measure of the potential resilience of communities.ResultsOur findings confirm the existence of a negative association between elevation and bird species richness in all European eco regions. However, we also explored a novel aspect of this relationship, important for conservation: Our findings provide evidence at large spatial scale of a negative association between the functional evenness (potential community resilience) and elevation, independent of the eco region. We also found that the Natura2000 protected areas covers the territory most in need of protection, those characterized by bird communities with low potential resilience, in hilly and mountainous areas.ConclusionsThese results draw attention to European areas occupied by bird communities characterized by a potential lower capacity to respond to strong ecological changes, and, therefore, potentially more exposed to risks for conservation.

Plant diversity and species richness of Ljubljana marsh grasslands under the influence of different cutting and fertilizing regimes

2009 ◽  
Vol 57 (2) ◽  
pp. 197-203 ◽  
Author(s):  
T. Sinkovč
Keyword(s):  
Species Richness ◽  
Plant Diversity ◽  
Grassland Management ◽  
Botanical Composition ◽  
Significant Negative Effect ◽  
Negative Effect ◽  
Cutting Regimes ◽  
N Rates ◽  
Exploitation Intensity ◽  
Plot Design

The botanical composition of grasslands determines the agronomic and natural values of swards. Good grassland management usually improves herbage value, but on the other hand it frequently decreases the plant diversity and species richness in the swards. In 1999 a field trial in a split-plot design with four replicates was therefore established on the Arrhenatherion type of vegetation in Ljubljana marsh meadows in order to investigate this relationship. Cutting regimes (2 cuts — with normal and delayed first cut, 3 cuts and 4 cuts per year) were allocated to the main plots and fertiliser treatments (zero fertiliser — control, PK and NPK with 2 or 3 N rates) were allocated to the sub-plots. The results at the 1 st cutting in the 5 th trial year were as follows: Fertilising either with PK or NPK had no significant negative effect on plant diversity in any of the cutting regimes. In most treatments the plant number even increased slightly compared to the control. On average, 20 species were listed on both unfertilised and fertilised swards. At this low to moderate level of exploitation intensity, the increased number of cuts had no significant negative effect on plant diversity either (19 species at 2 cuts vs. 20 species at 3 or 4 cuts). PK fertilisation increased the proportion of legumes in the herbage in the case of 2 or 3 cuts. The proportion of grasses in the herbage increased in all the fertilisation treatments with an increased numbers of cuts. Fertiliser treatment considerably reduced the proportion of marsh horsetail ( Equisetum palustre ) in the herbage of the meadows. This effect was even more pronounced at higher cut numbers. The proportion of Equisetum palustre in the herbage was the highest in the unfertilised sward with 2 cuts (26.4 %) and the lowest in the NPK-fertilised sward with 4 cuts (1.4%).

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