Aquatic Coleoptera and Hemiptera in some Canadian saline lakes: patterns in community structure

1987 ◽  
Vol 65 (6) ◽  
pp. 1383-1390 ◽  
Author(s):  
J. Lancaster ◽  
G. G. E. Scudder
Keyword(s):  
Cluster Analysis ◽  
Community Structure ◽  
Saline Lakes ◽  
Species Distributions ◽  
Ecological Classification ◽  
Feeding Guild ◽  
Classification Schemes ◽  
Fishless Lakes ◽  
Wide Range ◽  
Community Complexity

Communities of aquatic Coleoptera and Hemiptera were examined in eight fishless lakes of varying salinities in central British Columbia. A total of 28 coleopteran and 8 hemipteran species were collected. Taxonomic and ecological classification schemes, cluster analysis, and quantitative parameters were used to elucidate patterns of community structure from survey data. Species were characteristic of high, moderate, or low salinities, or tolerant of all salinities encountered. Species distributions were disjunct at conductivities of 80 and 5000 μS cm−1, yet community complexity changed more gradually with salinity. Densities increased and species richness, species diversity, feeding guild diversity, and ecological category diversity decreased with increased conductivity. Predatory Coleoptera were well represented in all lakes, but herbivores were less abundant with increased salinity. A curious size–distribution pattern was observed: a wide range of species sizes occurred in the most freshwater lake, but fewer size classes and only small sizes were represented in more saline lakes. Several mechanistic hypotheses are suggested to explain the observed patterns.

scholarly journals An Analysis of Heterogeneity in German Speaking Birdwatchers Reveals Three Distinct Clusters and Gender Differences

Birds ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 250-260
Author(s):  
Christoph Randler
Keyword(s):  
Cluster Analysis ◽  
Optimal Solution ◽  
Social Bonding ◽  
Cluster Solution ◽  
Novice Group ◽  
Wide Range ◽  
German Speaking ◽  
Group Members ◽  
Bird Group ◽  
And Gender

The purpose of this study was to segment birdwatchers into clusters. Members from a wide range of bird related organizations, from highly specialized birders as well as Facebook bird group members were studied to provide a diverse dataset (n = 2766; 50.5% men). Birding specialization was measured with a battery of questionnaires. Birding specialization encompassed the three constructs of skill/competence, behavior, personal and behavioral commitment. Additionally, involvement, measured by centrality to lifestyle, attraction, social bonding, and identity, was used. The NbClust analyses showed that a three-cluster solution was the optimal solution. Then, k-means cluster analysis was applied on three groups: casual/novice, intermediate, and specialist/advanced birdwatchers. More men than women were in the specialist/advanced group and more women than men in the casual/novice group. As a conclusion, this study confirms a three-cluster solution for segmenting German birdwatchers based on a large and diverse sample and a broad conceptualization of the construct birding specialization. These data can be used to address different target audiences (novices, advanced birders) with different programs, e.g., in nature conservation.

scholarly journals Interaction between typical sulfonamides and bacterial diversity in drinking water

2018 ◽  
Vol 16 (6) ◽  
pp. 914-920 ◽  
Author(s):  
Qing Wu ◽  
Shuqun Li ◽  
Xiaofei Zhao ◽  
Xinhua Zhao
Keyword(s):  
Drinking Water ◽  
Community Structure ◽  
Microbial Community ◽  
Bacterial Community ◽  
Bacterial Diversity ◽  
Microbial Community Structure ◽  
Antibiotic Use ◽  
Community Diversity ◽  
Wide Range ◽  
Growth Of Bacteria

Abstract The abuse of antibiotics is becoming more serious as antibiotic use has increased. The sulfa antibiotics, sulfamerazine (SM1) and sulfamethoxazole (SMZ), are frequently detected in a wide range of environments. The interaction between SM1/SMZ and bacterial diversity in drinking water was investigated in this study. The results showed that after treatment with SM1 or SMZ at four different concentrations, the microbial community structure of the drinking water changed statistically significantly compared to the blank sample. At the genus level, the proportions of the different bacteria in drinking water may affect the degradation of the SM1/SMZ. The growth of bacteria in drinking water can be inhibited after the addition of SM1/SMZ, and bacterial community diversity in drinking water declined in this study. Furthermore, the resistance gene sul2 was induced by SM1 in the drinking water.

scholarly journals Effect of Farming and Rainfall on the Species Diversity, Population Density and Community Structure of Birds Breeding in the Kalahari Woodland, NE Namibia

Zoodiversity ◽  
2021 ◽  
Vol 55 (6) ◽  
pp. 451-458
Author(s):  
G. Kopij
Keyword(s):  
Community Structure ◽  
Species Diversity ◽  
Bird Species ◽  
Diversity Indices ◽  
Annual Rainfall ◽  
Feeding Guilds ◽  
Line Transect ◽  
Population Densities ◽  
Feeding Guild ◽  
Turtle Dove

The line transect method has been employed to assess species diversity, population densities and community structure of birds breeding in a mosaic of Kalahari Woodland and farmland, NE Namibia. The transect, 4.5 km long, was surveyed in 2014 and 2015. The total annual rainfall in 2014 was much higher than in 2015 (427 mm vs. 262 mm). In total, 40 breeding species in 2014, and 46 in 2015 were recorded. Six species were dominant in 2014 (Cape Turtle Dove, Laughing Dove, Emerald-spotted Dove, Blue Waxbill, and White-browed Scrub Robin) and only three species in 2015 (Cape Turtle Dove and Blue Waxbill and Yellow-fronted Canary). Although the cumulative dominance in 2014 almost doubled that in 2015, the Community Index in both years was almost identical. Also diversity indices and evenness index were very similar in both years compared. Granivorous birds were the most numerous feeding guild. Their contribution was similar in 2014 and 2015 (46.7 % vs. 43.4 %). Two other feeding guilds, insectivores and frugivores, comprised together more than 50 % in both years. The number of bird species and species diversity were not influenced by the differential rainfall. However, contrary to expectations, population densities of most bird species (at least the more numerous ones) were higher in the year with lower than in the year with higher rainfall. The number of species and species diversity was similar in the farmland and in neighbouring Kalahari Woodland in a pristine stage. However, population densities of most species were lower in the farmland than in the pristine woodland.

scholarly journals Spatial analysis of phylogenetic community structure: New version of a classical method

2015 ◽  
Author(s):  
Carlo Ricotta ◽  
Eszter EA Ari ◽  
Giuliano Bonanomi ◽  
Francesco Giannino ◽  
Duncan Heathfield ◽  
...  
Keyword(s):  
Community Structure ◽  
Spatial Scales ◽  
Point Pattern ◽  
Maximum Deviation ◽  
Individual Plant ◽  
Phylogenetic Distance ◽  
Phylogenetic Structure ◽  
Phylogenetic Community Structure ◽  
Point Patterns ◽  
Wide Range

The increasing availability of phylogenetic information facilitates the use of evolutionary methods in community ecology to reveal the importance of evolution in the species assembly process. However, while several methods have been applied to a wide range of communities across different spatial scales with the purpose of detecting non-random phylogenetic patterns, the spatial aspects of phylogenetic community structure have received far less attention. Accordingly, the question for this study is: can point pattern analysis be used for revealing the phylogenetic structure of multi-species assemblages? We introduce a new individual-centered procedure for analyzing the scale-dependent phylogenetic structure of multi-species point patterns based on digitized field data. The method uses nested circular plots with increasing radii drawn around each individual plant and calculates the mean phylogenetic distance between the focal individual and all individuals located in the circular ring delimited by two successive radii. This scale-dependent value is then averaged over all individuals of the same species and the observed mean is compared to a null expectation with permutation procedures. The method detects particular radius values at which the point pattern of a single species exhibits maximum deviation from the expectation towards either phylogenetic aggregation or segregation. Its performance is illustrated using data from a grassland community in Hungary and simulated point patterns. The proposed method can be extended to virtually any distance function for species pairs, such as functional distances.

Cluster Analysis

2014 ◽  
pp. 123-159
Author(s):  
Pankaj Nagar
Keyword(s):  
Cluster Analysis ◽  
Policy Development ◽  
Good Governance ◽  
Unsupervised Classification ◽  
Business Organizations ◽  
Statistical Tools ◽  
Managerial Decisions ◽  
Wide Range ◽  
Spss Software ◽  
Societal Problems

The cluster analysis, also known as grouping, clumping, unsupervised classification, is one of the multivariate analysis techniques. The technique of cluster analysis is highly useful in a wide range of problems related to managerial decisions, psychological solutions, categorization of business organizations on the basis of their performance for constructing separate policies for each clusters, in health sectors, societal problems, etc. For good governance there is a need to apply the proper statistical tools with ICT. Even today, the statistical tools are rarely used in the region of e-governance for better policy development. This chapter discusses the use of cluster analysis in classifying a large amount of data into sub-groups (known as clusters), which are homogeneous in a certain sense, and analyzes each sub-group separately to find solutions for each of them. The method in explained with the help of an illustration, by using the SPSS software.

Cluster Analysis with General Latent Class Model

2011 ◽  
pp. 225-230
Author(s):  
Dingxi Qiu ◽  
Edward C. Malthouse
Keyword(s):  
Cluster Analysis ◽  
Statistical Models ◽  
Latent Variable ◽  
Latent Class ◽  
Latent Class Model ◽  
Teaching Style ◽  
Teaching Styles ◽  
Binary Responses ◽  
Cluster Membership ◽  
Wide Range

Cluster analysis is a set of statistical models and algorithms that attempt to find “natural groupings” of sampling units (e.g., customers, survey respondents, plant or animal species) based on measurements. The observable measurements are sometimes called manifest variables and cluster membership is called a latent variable. It is assumed that each sampling unit comes from one of K clusters or classes, but the cluster identifier cannot be observed directly and can only be inferred from the manifest variables. See Bartholomew and Knott (1999) and Everitt, Landau and Leese (2001) for a broader survey of existing methods for cluster analysis. Many applications in science, engineering, social science, and industry require grouping observations into “types.” Identifying typologies is challenging, especially when the responses (manifest variables) are categorical. The classical approach to cluster analysis on those data is to apply the latent class analysis (LCA) methodology, where the manifest variables are assumed to be independent conditional on the cluster identity. For example, Aitkin, Anderson and Hinde (1981) classified 468 teachers into clusters according to their binary responses to 38 teaching style questions. This basic assumption in classical LCA is often violated and seems to have been made out of convenience rather than it being reasonable for a wide range of situations. For example, in the teaching styles study two questions are “Do you usually allow your pupils to move around the classroom?” and “Do you usually allow your pupils to talk to one another?” These questions are mostly likely correlated even within a class.

scholarly journals Genetic diversity in potato (Solanum tuberosum L.)

1970 ◽  
Vol 36 (2) ◽  
pp. 121-125 ◽  
Author(s):  
MAA Mondal ◽  
MM Hossain ◽  
MG Rasul ◽  
M Shalim Uddin
Keyword(s):  
Genetic Diversity ◽  
Cluster Analysis ◽  
Multivariate Analysis ◽  
Solanum Tuberosum ◽  
Key Words ◽  
Diversity Pattern ◽  
Wide Range ◽  
Cluster Distance ◽  
Range Of Variation

Genetic diversity in 31 potato genotypes (parents and their hybrid progenies) was determined using multivariate analysis. Cluster analysis revealed that the parents and their hybrid progenies could be grouped into five different clusters. The maximum number of genotypes were included in clusters II and V. Cluster V had maximum and cluster I had minimum intra-cluster distance. Cluster mean showed wide range of variation for several characters among single as well as multi-genotypic clusters. Considering diversity pattern, parents should be selected from clusters I, III and V for the improvement of potato.   Key words: Genetic diversity, Cluster analysis, Potato DOI = 10.3329/bjb.v36i2.1499 Bangladesh J. Bot. 36(2): 121-125, 2007 (December)

scholarly journals Fish assemblages in a tidal flat

2003 ◽  
Vol 46 (2) ◽  
pp. 233-242 ◽  
Author(s):  
Ana Lúcia Vendel ◽  
Sabine Granado Lopes ◽  
César Santos ◽  
Henry Louis Spach
Keyword(s):  
Cluster Analysis ◽  
Community Structure ◽  
Tidal Flat ◽  
Seasonal Changes ◽  
Dominant Species ◽  
Fish Assemblages ◽  
Seasonal Pattern ◽  
Abundant Species ◽  
Structure Index ◽  
Total Capture

Studies were carried out on fish assemblages in a tidal flat. Samples were obtained monthly at low tide of the half moon in the tidal flat of Paranaguá Bay, Brazil, with two seine nets, one with a 1 mm mesh, 30 m in length and 3 m in height and another with a 10 mm mesh, 65 m in length and 2 m in height. A total of 8,890 fish were captured, comprising 24 families and 53 species. The most abundant species were Harengula clupeola and Atherinella brasiliensis, which represented 63.4% of the total, capture. A seasonal tendency was observed in the abundance of fishes, with less fishes being captured during winter and part of spring. The number of species showed a seasonal pattern, with the gradual decrease through winter and a marked increase in summer. The community structure index indicated seasonal changes in the assemblage. The faunistic similarities between months separated the 12 months into four major groups. The seasonal pattern was apparent in the numerically dominant species and the Cluster Analysis revealed five main groups.

scholarly journals Modelling community structure and species co-occurrence using fishery observer data

2016 ◽  
Vol 73 (7) ◽  
pp. 1750-1763 ◽  
Author(s):  
Jeffrey Robert Pulver ◽  
Hui Liu ◽  
Elizabeth Scott-Denton
Keyword(s):  
Cluster Analysis ◽  
Community Structure ◽  
Gulf Of Mexico ◽  
Reef Fish ◽  
Efficient Method ◽  
Probabilistic Models ◽  
Distinct Species ◽  
Common Species ◽  
Species Relationships ◽  
Correlation Measure

Abstract In this study, we modelled fishery observer data to compare methods of identifying community structure using cluster analyses to determine stratifications and probabilistic models for examining species co-occurrence in the Gulf of Mexico deepwater reef fish fishery. Comparing cluster analysis methods, the correlation measure of dissimilarity in combination with average agglomerative linkage was the most efficient method for determining species relationships using simulated random species as a comparison tool. Cluster analysis revealed distinct species stratifications and in combination with multiscale bootstrapping generated probabilities indicating the strength of stratifications in the fishery. A more parsimonious approach with probabilistic models was also developed to quantify pairwise species co-occurrence as random, positive, or negative based on the observed vs. expected fishing sets with co-occurrence. For the most common species captured, the probabilistic models predicted positive or negative co-occurrence between 84.2% of the pairwise combinations examined. These methods provide fishery managers tools for determining multispecies quota allocations and offer insights into other bycatch species of interest.

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