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Abstract

A comprehensive, but simple-to-use software package for executing a range of standard numerical analysis and operations used in quantitative paleontology has been developed. The program, called PAST (PAleontological STatistics), runs on standard Windows computers and is available free of charge. PAST integrates spreadsheettype data entry with univariate and multivariate statistics, curve fitting, time-series analysis, data plotting, and simple phylogenetic analysis. Many of the functions are specific to paleontology and ecology, and these functions are not found in standard, more extensive, statistical packages. PAST also includes fourteen case studies (data files and exercises) illustrating use of the program for paleontological problems, making it a complete educational package for courses in quantitative methods.
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... Two non-metric multidimensional scaling (NMDS) ordinations were performed to determine the differences in arthropod community composition among (1) fragments sizes and (2) habitat types. The NMDS was performed using a similarity matrix and the Bray-Curtis index as a distance metric using the software PAST 4.03 (Hammer et al. 2001;Vaca-Sánchez et al. 2021). After, a non-parametric permutation procedures (ANOSIMs) were carried to check whether arthropod species composition differed between all pairs of study sites. ...
... After, a non-parametric permutation procedures (ANOSIMs) were carried to check whether arthropod species composition differed between all pairs of study sites. These analyses were performed using PAST software (Hammer et al. 2001;Vaca-Sánchez et al. 2021). ...
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... Pollen data were summarized in a diagram in the software R (R Core Team, 2020) using the packages "Rioja" (Juggins, 2020) and "Vegan" (Oksanen et al., 2019). Pollen data were log-transformed and analyzed using Principal component analysis (PCA; Kenkel, 2006;Legendre and Birks, 2012) using PAST (Hammer et al., 2001). Various datasets containing all samples and taxa, as well as on the limited 79 sample dataset that excluded Poaceae (dominance) and Cyperaceae (because their thin wall impacted preservation in the deeper section of the core; Li et al., 2005;Jantz et al., 2013), were utilized to examine potential biases. ...
... Biodiversity indices also were calculated based on pollen counts using PAST (Hammer et al., 2001) to increase the evaluation of taxonomic richness against taxonomic evenness (Pardoe et al., 2021). A combination of biodiversity metrics was used to overcome the shortcomings of single parameter methods; selected metrics included the Shannon heterogeneity index (Shannon H Index) to determine the diversity of assemblages and address the issue of varying pollen counts per sample, taxonomic evenness to compare the relative abundance of pollen taxa in different assemblages, dominance to highlight if single taxa comprise the main count of a sample, and rarefaction analysis set to a sample size of 100 counted pollen grains to standardize diversity measurements among the different samples (Pardoe et al., 2021 and references therein). ...
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... A minimum of 500 valves were counted at 1000× magnification and identified according to Metzeltin & García-Rodríguez (2003) and Metzeltin et al. (2005). Diatom association zones were identified by cluster analysis using the Morisita index as advised by Hammer et al. (2001) to constrain similarity to contiguous intervals, which was performed for the whole 45-cm-long sediment core for 23 selected sediment intervals. The changes in isotopic composition in δ 13 C and δ 15 N were evaluated by Principal Component Analysis (PCA). ...
... The changes in isotopic composition in δ 13 C and δ 15 N were evaluated by Principal Component Analysis (PCA). All statistical tests were performed with PAST version 2.17c (Hammer et al., 2001). ...
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The combined use of paleolimnological and long-term limnological information to identify natural and anthropogenic environmental changes O uso combinado de informação paleolimnológica e limnológica histórica para identificar mudanças ambientais naturais e antropogênicas Cite as: García-Rodríguez, F. et al. The combined use of paleolimnological and long-term limnological information to identify natural and anthropogenic environmental changes. Acta Limnologica Brasiliensia, 2022, vol. 34, e28. Abstract: Aim: Urbanization leads to rapid changes in ecosystem structure and function. Wetlands on university campuses under urbanization pressure could be used as case studies of multidisciplinary aquatic research and good environmental practices promoting sustainability. Methods: A paleolimnological study was undertaken in a semi-artificial lake on a university campus in southern Brazil to trace historical impacts and ecological changes back to the mid-1970s through complementary approaches: historical data, nutrients, δ 13 C and δ 15 N stable isotopes, diatoms, microplastics and associated microbial community analysis. Results: The eutrophication process started to intensify after the lake was used for nocturnal roosting by waterbirds, and especially after the establishment of constructions along the margins with septic tank sanitary sewage, which eventually spilled and leached into the lake. Over decades, we identified a limnological hypertrophication process leading to recurrent cyanobacterial blooms and massive macrophyte proliferation coupled with changes in isotopic ratios and algal occupation with several transitions between shallow lake alternative states. Such a limnological process has resembled the paleolimnological eutrophication trends and isotopic changes in sedimentary organic matter. The microplastic deposition was detected as a proxy for the intensification of urbanization, especially during the construction of the University facilities. Conclusions: The combined use of paleolimnological and historical limnological data represents a powerful approach for inferring both natural and cultural impacts on the lake, and identifying management strategies based on such scientific information.
... Se utilizaron los paquetes estadísticos Infostat versión 2018 (Di Renzo et al. 2018), PCOrd 6 (McCune and Mefford 2011) y PAST ver. 3.26(Hammer et al. 2001). R��������� A nivel de comunidad se registraron 79 especies de plantas (Tabla 1), 46% de las cuales fueron anuales; dentro de las perennes, 25% fueron monocotiledóneas, en su mayoría Carex bonariensis Desf. ...
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Seriation of an original data matrix provides the paleoecologist with a simple and powerful tool for data manipulation. The data matrix lists the presences and absences of taxa in samples. The strategy is to generate a unidimensional sequence by rearranging the taxa and samples so that the presences are blocked along the matrix diagonal. The method is illustrated with two case studies from the Middle Devonian Hamilton Group of New York. The first represents a regressive interval and the seriation sequence summarizes the changes in fauna and samples which can be explained by falling sea level. The second example embraces a much wider range of variation. Seriation mainly recovers a first-order pattern related to depth and correlated variables. This seriation does not reveal parameters such as the nature of the substrate, turbidity, habitat stability and distance offshore. These data cannot be reduced to one dimension. In all cases, seriation yields results similar to those of cluster analysis and the first axis of multivariate ordinations frequently used by ecologists and paleoecologists. Seriation, paleoecology, Devonian, Hamilton Group, multivariate analysis.
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