scholarly journals Do persistent rare species experience stronger negative frequency dependence than common species?

2017 ◽  
Vol 26 (5) ◽  
pp. 513-523 ◽  
Author(s):  
Glenda Yenni ◽  
Peter B. Adler ◽  
S. K. Morgan Ernest
Keyword(s):  
Frequency Dependence ◽  
Rare Species ◽  
Common Species

scholarly journals Do persistent rare species experience stronger negative frequency dependence than common species?

2016 ◽  
Author(s):  
Glenda Yenni ◽  
Peter Adler ◽  
Morgan Ernest
Keyword(s):  
Frequency Dependence ◽  
Relative Abundance ◽  
Rare Species ◽  
Species Abundance ◽  
Common Species ◽  
Ecological Communities ◽  
Significant Challenge ◽  
Theoretical Pattern ◽  
Taxonomic Groups ◽  
Natural Communities

Understanding why so many species are rare yet persistent remains a significant challenge for both theoretical and empirical ecologists. Yenni, Adler, and Ernest (2012) proposed that strong negative frequency dependence causes species to be rare while simultaneously buffering them against extinction. This hypothesis predicts that, on average, rare species should experience stronger negative frequency dependence than common species. However, it is unknown if ecological communities generally show this theoretical pattern, or if rarity is primarily determined by other processes that overwhelm the effects of strong negative frequency dependence. We discuss the implications of this mechanism for natural communities, and develop a method to test for a non-random relationship between negative frequency dependence and relative abundance, using species abundance data from 90 communities across a broad range of environments and taxonomic groups. To account for biases introduced by measurement error, we compared the observed correlation between species relative abundance and the strength of frequency dependence against expectations from a randomization procedure. In approximately half of the analyzed communities, rare species showed disproportionately strong negative frequency dependence compared to common species. Specifically, we found a pattern of increasingly strong negative frequency dependence with decreasing relative abundance. Our results suggest that strong negative frequency dependence is a signature of both rarity and persistence for many species in many communities.

First data on plasmodial slime moulds (Myxomycetes = Myxogastrea) of Rdeysky Nature Reserve (Novgorod Region, Russia)

2021 ◽  
Vol 55 (2) ◽  
pp. 361-377
Author(s):  
N. I. Borzov ◽  
F. M. Bortnikov ◽  
A. V. Matveev ◽  
V. I. Gmoshinskiy
Keyword(s):  
Species Diversity ◽  
Rare Species ◽  
Nature Reserve ◽  
Common Species ◽  
Slime Moulds ◽  
State Nature Reserve ◽  
Plasmodial Slime Moulds ◽  
State Nature

The results of the first study of the species diversity of myxomycetes of the Rdeysky State Nature Reserve are presented. The 201 field specimens of sporophores belonging to 56 morphospecies from 27 genera, ten families, and six orders were collected from September 30 to October 5, 2020. Fifty-two species of these were new for the Novgorod Region. The most common species at the reserve were Arcyria affinis, Hemitrichia calyculata, Lycogala epidendrum, Metatrichia vesparia, Physarum album, Trichia decipiens, and T. varia. Additionally, detailed morphological descriptions of two rare species Amaurochaete trechispora and Trichia crateriformis are given.

scholarly journals Locally rare species influence grassland ecosystem multifunctionality

2016 ◽  
Vol 371 (1694) ◽  
pp. 20150269 ◽  
Author(s):  
Santiago Soliveres ◽  
Peter Manning ◽  
Daniel Prati ◽  
Martin M. Gossner ◽  
Fabian Alt ◽  
...  
Keyword(s):  
Land Use ◽  
Rare Species ◽  
Common Species ◽  
Ecosystem Functions ◽  
Individual Species ◽  
Conservation Priorities ◽  
Below Ground ◽  
Species Specific ◽  
The Relationship ◽  
Ecosystem Multifunctionality

Species diversity promotes the delivery of multiple ecosystem functions (multifunctionality). However, the relative functional importance of rare and common species in driving the biodiversity–multifunctionality relationship remains unknown. We studied the relationship between the diversity of rare and common species (according to their local abundances and across nine different trophic groups), and multifunctionality indices derived from 14 ecosystem functions on 150 grasslands across a land-use intensity (LUI) gradient. The diversity of above- and below-ground rare species had opposite effects, with rare above-ground species being associated with high levels of multifunctionality, probably because their effects on different functions did not trade off against each other. Conversely, common species were only related to average, not high, levels of multifunctionality, and their functional effects declined with LUI. Apart from the community-level effects of diversity, we found significant positive associations between the abundance of individual species and multifunctionality in 6% of the species tested. Species-specific functional effects were best predicted by their response to LUI: species that declined in abundance with land use intensification were those associated with higher levels of multifunctionality. Our results highlight the importance of rare species for ecosystem multifunctionality and help guiding future conservation priorities.

scholarly journals Ecology of sandflies (Diptera: Psychodidae) in a restricted focus of cutaneous leishmaniasis en Northern Venezuela: I. Description of the study area, catching methods and species composition

1987 ◽  
Vol 82 (1) ◽  
pp. 119-124 ◽  
Author(s):  
M. Dora Feliciangeli
Keyword(s):  
Species Composition ◽  
Cutaneous Leishmaniasis ◽  
Relative Abundance ◽  
Rare Species ◽  
Common Species ◽  
Term Study ◽  
Phlebotomine Sandfly ◽  
Phlebotomine Sandflies ◽  
The Common ◽  
Catching Methods

A study on the ecology of phlebotomine sandfly fauna in a restricted focus of cutaneous leishmaniasis in northern Venezuela was undertaken in order to investigate the species responsible for the transmission. The study area and catching methods for phlebotomine sandflies are described. A total of 9,061 females and 1,662 males were collected during a year-term study. 12 species of Lutzomya and 1 species of Brumptomya sp. were identified. Absolute and relative abundance and ocurrence for each species were determined. The rel ative occurrence allowed to distinguish the common species, viz. L. panamensis, L. ovallesi, L. gomezi, L. tinidadensis, L. atroclavata, L. cayennensis, L. shannoni and L. olmeca bicolor from the rare species vis., L. punctigeniculata, L. rangeliana, L. evansi and L. dubitans. General comments on the species composition of the sandfly fauna in this locality are made.

The Biology of Schistomysis Kervillei [Crustacea, Mysidacea]

1971 ◽  
Vol 51 (3) ◽  
pp. 653-658 ◽  
Author(s):  
J. Mauchline
Keyword(s):  
Rare Species ◽  
Common Species ◽  
North West ◽  
Summer Generation

Schistomysis kervillei (G. O. Sars) is a common species in Loch Ewe, Gairloch and Gruinard Bay in north-west Scotland and a rare species in the Firth of Clyde. It breeds throughout the year but most intensely in the spring and summer, to produce a spring and summer generation of young. The maximum number of young found in a marsupium was 47. The species is omnivorous. Its biology is briefly compared with that of S. spiritus (Norman) and S. ornata (G. O. Sars).

Industrial Development and the Conservation of Vascular Plants, with Special Reference to Britain

1984 ◽  
Vol 11 (3) ◽  
pp. 235-245 ◽  
Author(s):  
John G. Kelcey
Keyword(s):  
Rare Species ◽  
Industrial Development ◽  
Species Conservation ◽  
Industrial Process ◽  
Nutrient Status ◽  
Common Species ◽  
Wild Plants ◽  
Slope Aspect ◽  
Conservation Movement ◽  
The Creation

This paper, which has been nearly a decade in gestation, describes the contribution that industrial development makes to the conservation of wild plants in Britain. It challenges the priorities of the British conservation movement in concentrating its efforts on rare species and habitats, on the creation of Nature reserves, and on the maintenance of rare species as rare species. A more positive approach is now advocated, stressing the need to prevent common species from becoming rare, the creation of new habitats, and the propagation and reintroduction of uncommon species.Whilst species conservation is relatively easy to justify and comprehend, habitat conservation is considerably more difficult. ‘Industrial habitats’ may be defined as those derived from any industrial process (including transport routes). Such habitats are characterized by a complex association and interaction of slope, aspect, drainage, nutrient status, and the chemical and physical characteristics of the skeletal soils—all of which are apt to change markedly over very short distances. In addition they are generally open, lack stability, do not receive frequent applications of fertilizer and/or herbicide, and are often inaccessible or well protected.

Composition and structure of Orthopteran faunas in cereal crops in Ethiopia

1992 ◽  
Vol 82 (1) ◽  
pp. 29-39 ◽  
Author(s):  
Tibebu Habtewold ◽  
Jan Landin
Keyword(s):  
Species Richness ◽  
Rare Species ◽  
Common Species ◽  
Black Soil ◽  
Cereal Crops ◽  
South Eastern ◽  
Light Soil ◽  
Composition And Structure

AbstractAdult grasshopper (Orthoptera: Acridoidea, Tetrigioidea Tettigonioidea) assemblages were sampled at four localities in south-eastern Shoa, around Debre Zeit, Ethiopia, between August 1986 and September 1988. Three localities were followed for the whole period but the fourth locality was followed only between August 1986 and July 1987. Samples were taken fortnightly from both black and light soil fields of tef and wheat crops, each in three replicates. The fauna consisted of twenty-nine taxa of both short- and longhorned grasshoppers, twenty-six of which are identified to species. Over 70% of the species belong to Acrididae and most of them are either pests or potential pests of cereal crops. Species richness, diversity and dominance within and between sites and seasons did not differ much during the two year period. The composition and structure of the assemblage was relatively constant. Despite fluctuation in abundance, dominant and common species remained common and rare species rare. Aiolopus longicornis Sjöstedt was most dominant. Some species are more abundant on black soil than on light soil and vice versa. The results are compared to grasshopper assemblages studied elsewhere.

Spatial distributions of species in an old-growth temperate forest, northeastern China

2010 ◽  
Vol 40 (6) ◽  
pp. 1011-1019 ◽  
Author(s):  
Xugao Wang ◽  
Ji Ye ◽  
Buhang Li ◽  
Jian Zhang ◽  
Fei Lin ◽  
...  
Keyword(s):  
Rare Species ◽  
Temperate Forests ◽  
Common Species ◽  
Average Density ◽  
Northeastern China ◽  
Neighborhood Density ◽  
Dispersal Ability ◽  
Spatial Distributions ◽  
Canopy Layer ◽  
Spacing Effects

Studying spatial distributions of species can provide important insights into processes and mechanisms that maintain species richness. We used the relative neighborhood density Ω based on the average density of conspecific species in circular neighborhoods around each species to quantify spatial distributions of species with ≥10 individuals in a fully mapped 25 ha temperate plot at Changbaishan, northeastern China. Our results show that spatial aggregation is a dominant pattern of species in the Changbaishan temperate forests. However, the percentage of significantly aggregated species decreases with spatial scale, especially for rare species. Rare species are more aggregated than intermediate and common species. The aggregation intensity declines with increasing size class (diameter at breast height), i.e., species become more regularly spaced as species grow, which is consistent with the predictions of self-thinning and Janzen–Connell spacing effects. Species functional traits (canopy layer, seed dispersal ability, shade tolerant, etc) also havea significant effect on the spatial distributions of species. Our results partially conform to the prediction that better dispersal reduces aggregation. Consequently, dispersal limitation, self-thinning, Janzen–Connell spacing effects, and habitat heterogeneity may primarily contribute to spatial distributions of species in the temperate forests.

scholarly journals Lung microbiome alterations in NSCLC patients

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Leliang Zheng ◽  
Ruizheng Sun ◽  
Yinghong Zhu ◽  
Zheng Li ◽  
Xiaoling She ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Cancer Progression ◽  
Rare Species ◽  
Common Species ◽  
Oral Microbiota ◽  
Metagenomic Sequencing ◽  
Microbial Composition ◽  
Lung Microbiome ◽  
Egfr Expression ◽  
Nsclc Patients

AbstractLung is colonized by a diverse array of microbes and the lung microbiota is profoundly involved in the development of respiratory diseases. There is little knowledge about the role of lung microbiota dysbiosis in lung cancer. In this study, we performed metagenomic sequencing on bronchoalveolar lavage (BAL) from two different sampling methods in non-small cell lung cancer (NSCLC) patients and non-cancer controls. We found the obvious variation between bronchoscopy samples and lobectomy samples. Oral taxa can be found in both bronchoscopy and lobectomy samples and higher abundance of oral taxa can be found in bronchoscopy samples. Although the NSCLC patients had similar microbial communities with non-cancer controls, rare species such as Lactobacillus rossiae, Bacteroides pyogenes, Paenibacillus odorifer, Pseudomonas entomophila, Magnetospirillum gryphiswaldense, fungus Chaetomium globosum et al. showed obvious difference between NSCLC patients and non-cancer controls. Age-, gender-, and smoking-specific species and EGFR expression-related species in NSCLC patients were detected. There results implicated that different lung segments have differential lung microbiome composition. The oral taxa are found in the lobectomy samples suggesting that oral microbiota are the true members of lung microbiota, rather than contamination during bronchoscopy. Lung cancer does not obviously alter the global microbial composition, while rare species are altered more than common species. Certain microbes may be associated with lung cancer progression.

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