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LIKELIHOOD METHODS AND MODELS IN ECOLOGY

 

April 2 – 6, 2012

Cary Institute of Ecosystem Studies

Millbrook, NY

 

INSTRUCTOR: 

Dr. Charles D. Canham, email: canhamc@caryinstitute.org

 

 

Day 1

8:30  –  9:30    Lecture 1:  An Introduction to Likelihood for Estimation and Inference    [Simple Example in Excel]

9:30  – 10:15   Case Study 1:   Distribution and Abundance of Tree Species Along Climate Gradients  [Canham and Thomas 2010]

10:15 – 10:30  Break

10:30 – 12:00  Lab  1:  Calculating Likelihood, Likelihood Surfaces, and Likelihood Profiles    [R Code – Section 1]  [R Code – Section 2]

12:00 –  1:00   Lunch

1:00  –  2:00    Lecture 2:  Parameter Estimation and Evaluation of Support

2:00  –   5:00   Lab 2: Global Optimization using Simulated Annealing and Genetic Algorithms 

[R code – anneal]   [R code – genoud]  [R code – optim] 

[BC Sapling Growth Data – Excel Version] [BC Sapling Growth Data.txt – (right click and “Save as…”)]

[Wright et al. 1998]

Recommended Reading for Day 2: 

Gσmez-Aparicio, L. and C. D. Canham.  2008.  A neighborhood analysis of the allelopathic effects of the invasive tree Ailanthus altissima in temperate forests.  Journal of Ecology 96:447-458

 

 

Day 2

8:30 – 9:30       Lecture 3:  Hypothesis Testing and Statistical Inference Using Likelihood: The Central Role of Models

9:30 – 10:15     Case Study 2: Neighborhood Models Of The Allelopathic Effects Of An Invasive Tree Species

10:15 – 10:30   Break

10:30 – 12:00   Lab  3:  Likelihood Functions for Continuous and Count Data: A Plethora of PDFs

                                    [McLaughin 1993 – Compendium of Common Probability Distributions]

                                    [Normal PDF with non-homogeneous variances]

                                    [Gamma and Lognormal PDFs]  [Exponential PDF]   [Beta PDF]

                                    [Poisson, Negative Binomial, and Zero-Inflated PDFs]

12:00   –  1:00 Lunch

1:00   – 2:00    Lecture 4:  Model Selection: AIC and Akaike Weights, Multi-model Inference  

2:00  –  5:00    Lab 4:  Model Comparison and Hypothesis Testing in a Likelihood Framework

                                    [Lab 4 R Script]

Recommended Reading for Day 3: (either of the 2 listed below) 

Canham, C. D., M. Papaik, M. Uriarte, W. McWilliams, J. C. Jenkins, and M. Twery.  2006. Neighborhood analyses of canopy tree competition along environmental gradients in New England forests.  Ecological Applications 16:540-554.

Canham, C. D., Papaik, M. J., and Latty, E. F.  2001.  Interspecific variation in susceptibility to windthrow as a function of tree size and storm severity for northern temperate tree species.  Canadian Journal of Forest Research 31:1-10.

 

Day 3

8:30   – 9:30    Lecture 5:  Model Evaluation:  How good is the best model?

9:30 – 10:15    Case Study 3:  Neighborhood Models of Tree Competition

10:15 – 10:30  Break

10:30 – 12:00  Lab 5:  Model Evaluation   [Sample R Code for Model Evaluation]

12:00  –  1:00  Lunch

1:00  –  2:00     Lecture 6:  Analysis of Categorical and Ordinal Data:  Binomial and Logistic Regression

2:00  –  5:00    Lab 6: Developing your own binomial and logistic regression models in R

[R code – Logistic regression of windthrow data]   [Damagedata.Rdata]  [R code – binomial regression]

 

Recommended Reading for Day 4

Johnson, J. B., and K. S. Omland. 2004. Model selection in ecology and evolution.  Trends in Ecology and Evolution 19(2):101-108.

MacKenzie et al. 2002.  Estimating site occupancy rates when detection probabilities are less than one.  Ecology 83(8):2248-2255.

 

Day 4

8:30   – 9:30    Lecture 7:  Avoiding and Dealing with Problems with Your Data and Models:  Sampling Design, Lack of Independence, Spatial Autocorrelation, Collinearity, Parameter Tradeoffs,…

9:30 – 10:15    Discussion:  Presenting and explaining your results in the language of likelihood

10:15 – 10:30  Break

10:30 – 12:00  Lab 7:  Detection Probability    [Models for Estimating Site Occupancy when Detection Probability is < 1 (doc file)] [R Code]

12:00   –  1:00 Lunch

1:00 –   5:00   Lab Project:  Fundamental vs. Realized Niches of North American Tree Species Along Climate Gradients

                        [See the Course Materials page for datasets, R scripts, and documentation for the project]

                        [Course Materials Page]

                       

Day 5

8:30 – 12:00    Lab Projects, continued

12:00 – 1:00    Lunch

1:00 – 3:00      Presentations of Results from Lab Projects

3:00 – 5:00      Wrap-up Discussion:  Developing your own statistical tool-kit and philosophy

COURSE HOMEPAGE