Multivariate Statistics for Wildlife and Ecology Research

(NRC 631)

Lab Projects

The Multivariate Statistics for Wildlife and Ecology Research (NRC 631) Lab includes several major projects corresponding to the major statistical techniques covered in this course (see Schedule). Each of these projects are briefly described below and include links to detailed descriptions of each assignment and downloads of all required data and scripts. All documents in pdf format require Adobe Acrobat Reader to view.

Mvstats Pseudo-R-Library

Mvstats.R is suite of R functions written to facilitate the analysis of multivariate data sets in this course. This suite of functions is written in the spirit of growing up to become a fully fledged library in R, but for now it is just a humble set of functions that must be sourced before using. This library will be updated constantly, possibly for each lab, so it will need to be downloaded and sourced each lab. In addition, the corresponding help file contains all the supporting documentation for the functions and is written in the spirit of the standard R function help pages (for better or worse).

Lab 1: Introduction to R

The first lab will introduce students to the R programming and statistical computing environment. Students will gain only a preliminary working understanding of how to work in R. The purpose of this lab is to give students enough understanding and working skills to successfully complete the remaining lab projects, not teach students to become R experts.

Lab 2: Data screening and adjustment
This lab is designed to give students hands-on experience using R to prepare, screen and potentially adjust a multivariate data set in preparation for analysis. Students will not be expected to evaluate the data set from every possible angle and using every possible analytical procedure available. Rather, the purpose of this project is to give students some basic experience in screening and adjusting data using R.

Project 1: Unconstrained ordination

This project is designed to give students hands-on experience using a variety of unconstrained ordination techniques, including Principal Components Analysis (PCA), Correspondence Analysis (CA), Detrended Correspondence Analysis (DCA), Principal Coordinates Analysis (PCO) and Nonmetric Multidimensional Scaling (NMDS) to analyze a multivariate data set. As such, students will not be expected to analyze the data set from every possible angle and using every possible analytical procedure available. Rather, the purpose of this project is to give students some basic experience in how unconstrained ordination techniques work and how R an be used to do the analysis.

Project 2: Cluster analysis

This project is designed to give students hands-on experience using Cluster Analysis (CA) to analyze a multivariate data set. As such, students will not be expected to analyze the data set from every possible angle and using every possible analytical procedure discussed in class. Rather, the purpose of this project is to give students some basic experience in how CA works and how R can be used to do the analysis.

Project 3: Discrimination among groups
This project is designed to give students hands-on experience using Discriminant Analysis (DA), Classification and Regression Trees (CART) and Multi-response Permutation Procedures (MRPP) to analyze one of several available multivariate data sets. The purpose of this project is to expose students to DA, CART and MRPP procedures for exploration, description and prediction of grouped data. As such, students will not be expected to analyze the data set from every possible angle and using every analytical procedure available. Rather, the purpose of this project is to give students some basic experience in how various discrimination techniques work and how R can be used to do the analysis.

Project 4: Constrained Ordination (CCA and RDA)

This project is designed to give students hands-on experience using constrained ordination (CCA/RDA/CAP) to analyze a multivariate data sets. Specifically, students will learn how to conduct Canonical Correspondence Analysis (CCA) or Redundancy Analysis (RDA) using R. Constrained Analysis of Principal Coordinates (CAP) is similar but will not be done here. Students will learn how to screen and adjust the data set (e.g., select species and explanatory variables) and conduct the constrained ordination. In addition, students will learn how to evaluate the performance of the model and interpret the relationships among species, samples and environmental variables. Finally, students will learn how to do a simple 2- or 3-part variance decomposition. Students will not be expected to analyze the data set from every possible angle and using every possible analytical procedure available. Rather, the purpose of this project is to give students some basic experience in how CCA/RDA work and how R can be used to do the analysis.


For more information, please contact:
Dr. Kevin McGarigal
Department of Natural Resources Conservation
University of Massachusetts
304 Holdsworth Natural Resources Center
Box 34210
Amherst, MA 01003
Fax: (413) 545-4358
Phone: (413) 577-0655
Email: mcgarigalk@forwild.umass.edu