Diversity, abundance and distribution of grasshopper species (Orthoptera: Acrididea) in three different types of vegetation with different levels of anthropogenic disturbances in the Littoral Region of Cameroon

2020 ◽  
Vol 14 (1) ◽  
pp. 16-33 ◽  
Author(s):  
YETCHOM-FONDJO JEANNE AGRIPPINE ◽  
KEKEUNOU - SÉVILOR ◽  
KENNE - MARTIN ◽  
MISSOUP ALAIN DIDIER ◽  
SHENG-QUAN XU

Grasshoppers have been identified as excellent monitors of landscape use. Despite their importance, their composition and distribution in the highly disturbed Littoral Cameroon is still unknown. The aim of this study was to determine the effect of human activities on diversity, abundance and distribution of grasshopper species in the Littoral region of Cameron. We investigated three types of vegetation differing remarkably on the level of anthropogenic impact (farmlands, fallows and forests), using sweep netting. The eight non-parametric estimators for specific richness, abundance, α and β diversity indices and species abundance distribution models, were used to compare the structure of communities among vegetation. Overall, 38 species belonging to three families and ten subfamilies were recorded. The Acrididae was the most diverse family. The species richness, abundance and diversity were higher in farmlands than in fallows and in forests. Five species occurred exclusively in farmlands, one in fallows and four in forests. Eyprepocnemis plorans, Coryphosima stenoptera, Serpusia opacula were overall the most abundant species respectively in cultivated farms, fallows and forests. Species abundance distribution fitted the Motomura model in all sites. Serpusia opacula is considered as a useful indicator since its presence and abundance significantly depend on the rate of forest naturalness. The farmlands were characterized by short vegetation while the fallows and forests were dominated by tall grasses and tall trees respectively. Anthropogenic disturbances promote the species richness, diversity and abundance of open meadow species, while it is detrimental to forest species which are sensitive, specialized and have limited dispersal abilities. Key words: Grasshopper, diversity, abundance, distribution, bioindicator

2019 ◽  
Vol 32 (1) ◽  
pp. 103-117
Author(s):  
Yang Wang ◽  
Huoming Zhou ◽  
Jingyong Cai ◽  
Congwen Song ◽  
Linzhao Shi

Author(s):  
Jean Béguinot

The genus Conus forms a conspicuous and rather homogeneous group within marine Gastropods. This makes it all the more interesting to focus on the sub-communities formed by Conus species and to analyze the potential specificities in the internal organization of species in these communities, in particular species richness, species abundance distribution and the effect of geographical distance between communities on differences in their respective species composition. Accordingly, two Conus communities along the coast in Mannar Gulf (India), separated by 80 km, are considered. Reliable analysis requires, first, to treat exhaustive data from complete samplings or, else – as here – to implement an appropriate extrapolation procedure to complete numerically the partial samplings. After numerical completion, substantial differences were highlighted between the two communities, not only in terms of true (total) species richness but, even more, as regards the profile and the average unevenness of the distributions of species abundance. Also, significant dissimilarity in species composition was found between the two communities, that may be tentatively attributed to either deterministic distance decay in similarity of species composition or, alternatively, to the persistence in the stochastic process of species recruitment from the regional stock of Conus planktonic larvae. This preliminary study yet requests to be complemented by other similar case studies, before drawing any safer interpretative conclusions.


2015 ◽  
Author(s):  
Elita Baldridge ◽  
David J. Harris ◽  
Xiao Xiao ◽  
Ethan P. White

AbstractA number of different models have been proposed as descriptions of the species-abundance distribution (SAD). Most evaluations of these models use only one or two models, focus only a single ecosystem or taxonomic group, or fail to use appropriate statistical methods. We use likelihood and AIC to compare the fit of four of the most widely used models to data on over 16,000 communities from a diverse array of taxonomic groups and ecosystems. Across all datasets combined the log-series, Poisson lognormal, and negative binomial all yield similar overall fits to the data. Therefore, when correcting for differences in the number of parameters the log-series generally provides the best fit to data. Within individual datasets some other distributions performed nearly as well as the log-series even after correcting for the number of parameters. The Zipf distribution is generally a poor characterization of the SAD.


2019 ◽  
Vol 135 ◽  
pp. 28-35 ◽  
Author(s):  
Pedro Manuel Villa ◽  
Sebastião Venâncio Martins ◽  
Alice Cristina Rodrigues ◽  
Nathália Vieira Hissa Safar ◽  
Michael Alejandro Castro Bonilla ◽  
...  

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2823 ◽  
Author(s):  
Elita Baldridge ◽  
David J. Harris ◽  
Xiao Xiao ◽  
Ethan P. White

A number of different models have been proposed as descriptions of the species-abundance distribution (SAD). Most evaluations of these models use only one or two models, focus on only a single ecosystem or taxonomic group, or fail to use appropriate statistical methods. We use likelihood and AIC to compare the fit of four of the most widely used models to data on over 16,000 communities from a diverse array of taxonomic groups and ecosystems. Across all datasets combined the log-series, Poisson lognormal, and negative binomial all yield similar overall fits to the data. Therefore, when correcting for differences in the number of parameters the log-series generally provides the best fit to data. Within individual datasets some other distributions performed nearly as well as the log-series even after correcting for the number of parameters. The Zipf distribution is generally a poor characterization of the SAD.


2014 ◽  
Vol 2014 ◽  
pp. 1-6
Author(s):  
Jean Béguinot

Anne Chao proposed a very popular, nonparametric estimator of the species richness of a community, on the basis of a limited size sampling of this community. This expression was originally derived on a statistical basis as a lower-bound estimate of the number of missing species in the sample and provides accordingly a minimal threshold for the estimation of the total species richness of the community. Hereafter, we propose an alternative, algebraic derivation of Chao’s estimator, demonstrating thereby that Chao’s formulation may also provide centered estimates (and not only a lower bound threshold), provided that the sampled communities satisfy a specific type of SAD (species abundance distribution). This particular SAD corresponds to the case when the number of unrecorded species in the sample tends to decrease exponentially with increasing sampling size. It turns out that the shape of this “ideal” SAD often conforms approximately to the usually recorded types in nature, such as “log-normal” or “broken-stick.”. Accordingly, this may explain why Chao’s formulation is generally recognized as a particularly satisfying nonparametric estimator.


2016 ◽  
Vol 70 ◽  
pp. 21-28 ◽  
Author(s):  
Simone Fattorini ◽  
François Rigal ◽  
Pedro Cardoso ◽  
Paulo A.V. Borges

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