Prerequisites
General knowledge of the basic concepts concerning plant ecology, flora, vegetation and of the topics of the Mathematics and statistics course. Current use of a pc with Windows operating system and of worksheet and word-processor software.
Learning outcomes
To introduce to the analysis of vegetation data (especially phytosociological tables) by means of multivariate statistic tools and getting used to the application of some free elaboration software packages. The aims are: to have the full comprehension of the information content of vegetational data recorded according to phytosociological method; to be able to plan and practice a proper analysis procedure, using multivariate techniques, motivating the methodological choices and giving a correct interpretation of the results.
Course contents
Vegetation data – Basic concepts of phytosociology. Limits and advantages of its application. The phytosociological relevè as basic operation of the sampling of the vegetation. The information included in the phytosociological relevè: head data (site parameters and structural data), floristic data. Building a raw phytosociological table. The syntesis of data in synoptic phytosociological tables. Protocols of analysis of vegetation data – Main questions: defining groups of similar relevès, identifying differential species. Ellenberg’s technique for the simple elaboration of a raw phytosociological table. Syntaxonomic references (prodromes and literature). Protocols of analysis of vegetational data by means of multivariate statistics tools: conversion of phytosociological codes into numbers; data transformation; similarity and distance measures; hierarchical and non hierarchical classifications; eigenvalues and eigenvectors ordinations; the analysis of results. Evaluation of the consistency of the results from different analytical approaches on the same data; Analysis of results taking into account site and structural parameters.. Available packages to analyze vegetation data – Basic management of phytosociological data using a worksheet; introduction to the use of some free software packages available online useful for vegetation analysis: package PAST, package WinTWINS and some functions of R libraries Vegan, VegClust, Indispecies and Labdsv di R. An introductive presentation of Cocktail method is eventually given.
Teaching methods
A few introductory classes concerning the bases of phytosociological method and computer practices on data provided by the student or by the teacher. Didactic materials include Power-Point presentations, summaries of the lessons, free statistic packages and selected papers from scientific journals concerning the description of analytical methods.
Reccomended or required readings
Barrai I., 1986 - Introduzione all’analisi multivariata. Edagricole, Bologna.
Causton D. R., 1988 - Introduction to Vegetation Analysis. Unwin Hyman Ltd, London.
Chytrý M., Otýpková Z., 2003 - Plot sizes used for phytosociological sampling of European vegetation. J. Veg. Sci. 14: 563-570.
De Caceres M., Wiser S. K., 2016 – How to use the Vegclust Package (Ver. 1.6.5). https://cran.r-project.org/web/packages/vegclust/vignettes/VegetationClassification.pdf
Digby & Kempton, 1987 - Multivariate analysis of ecological communities. Chapman and Hall, London.
Dufrêne M., Legendre, P., 1997 - Species assemblages and indicator species: The need for a flexible asymmetrical approach. Ecological Monographs 67: 345–366.
Feoli E., Lagonegro M., Zampar A., 1982 - Classificazione e ordinamento della vegetazione. metodi e programmi di calcolo. C.N.R. AQ/5/35, Udine
Hammer, Ø., Harper D.A.T. and P. D. Ryan, 2001 - PAST: Paleontological Statistics Software Package for Education and Data Analysis. Palaeontologia Electronica 4(1): 9pp. http://palaeo-electronica.org/2001_1/past/issue1_01.htm
Hill M.O., Smilauer P., 2005 - TWINSPAN for Windows version 2.3. Centre for Ecology and Hydrology & University of South Bohemia, Huntingdon & Ceske Budejovice.
Oksanen J., 2013 - Multivariate Analysis of Ecological Communities in R: vegan tutorial. (February 8, 2013).
Oksanen J., F. Blanchet G., Kindt R., Legendre P., Minchin P.R., O’Hara R. B., Simpson G.L., Solymos P., Stevens M.H., Wagner H., 2013 - The Package ‘vegan’. Community Ecology Package Version 2.0-7. (March 19, 2013)
Podani J., 2007 - Analisi ed esplorazione multivariata dei dati in ecologia e biologia. Liguori editore, Napoli
Poldini L., Sburlino G., 2005 – Terminologia fitosociologica essenziale. Fitosociologia 41(1): 57-69.
Van Der Maarel E., 1979 - Transformation of Cover-Abundance Values in Phytosociology and Its Effects on CommunitySimilarity. Vegetatio, 39(2): 97-114.
Westhoff V., Van Der Maarel E., 1973 – The Braun-Blanquet approach. In Whittaker R.H. ed. Ordination and Classification of Communities. Handbook of Vegetation Science 5: 619-707.
Assessment methods
Oral examination based on the discussion of a written report concerning the analysis of sample data of the student or provided by the teacher. In the report must be explained the characteristics of analyzed data, which methods have been applied, why such methods have been used and the results that have been obtained.
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