PPT-Ecological Niche Factor Analysis-ENFA

Gonzalo Rivas Spring 2010 Introduction to ENFA Species are expected to be nonrandomly distributed due to ecological and geographical variables Copyright Basille et al 2008 Variables amp Spatial location. Some Definitions. An . ecosystem. – all the living things in an area plus the physical or abiotic factors.. A . habitat . – the place or environment in which specific organisms live.. A . species. The scientific study of the distribution and abundance of organisms and the interactions that determine distribution and abundance. Begon. , Harper, Townsend, 2006, Ecology, Blackwell. Lecture outline. AnnMaria De Mars, PhD.. The Julia Group & 7 Generation Games . WHY?. Imagine this. What exactly were you planning on doing with that?. Let’s say you have a massive pile of data …. . You Could:. Raster maps of the study area, can be obtained by a different software like . ArcGis. .. -Raster map of the location of the target species (.. csv. format).. -Raster maps that contains the continuous values for each descriptive variable (.. Prepared by. Ferry . Dzulkifli. Tita. . Borshalina. FACTOR ANALYSIS. Factor Analysis Defined. Factor analysis . . .. is an interdependence technique whose primary purpose is to define the underlying structure among the variables in the analysis.. Lua Augustin, Savannah Guo, and Blair Marquardt. Learning Outcomes. To understand. :. What . is factor analysis.. What is its model.. Latent vs. observable variables; examples of each. .. Potential applications of factor analysis. The purpose of factor analysis is to discover patterns in the relationships among the . variables. Factor Analysis. Form of multiple correlations. Checking for construct validity. Do questions measure the same dimension?. cell. Ferrel. . cell. Ferrel. . cell. Hadley cell. Ferrel. cell. Polar cell. The Physical Environment. Image from NASA. Joseph Grinnell. Grinnellian. Niche . . . “Habitat”. “The niche relationships of the California Thrasher”. 10. 9. 8. 6. 5. 4. 3. 2. 1. Ecological Niche. The role played by an organism in a biological community: its food preferences, its requirements for shelter; its special behaviors, and the timing of its activities (nocturnal or diurnal). . The basic objective of Factor Analysis is data reduction or structure detection.. The purpose of . data reduction.  is to remove redundant (highly correlated) variables from the data file, perhaps replacing the entire data file with a smaller number of uncorrelated variables.. Dept. of PHS, Division of . Biostats. & . Bioinf. Biostatistics Shares Resource, Hollings Cancer Center. Cancer Control Journal Club. March 3, 2016. Motivating Example. Goals of paper. 1. See if previously defined measurement model of hopelessness in advanced cancer fits this sample. Confirmatory Factor Analysis.. By . Patricia Lane. Dalhousie University. Goal. : to illustrate how Dick Levins’ loop analysis is useful for analyzing complex systems using a marine ecosystem example. Rationale: we have one ocean, which is constantly under threat; we need to understand how perturbations affect ecological networks through a myriad of pathways and feedbacks. Ecological Niche models of plague in Uzbekistan : extracting biological information from multiple-species models vs. species specific models to understand hosts and vectors Jason K. Blackburn, PhD, variables. Factor Analysis. Form of multiple correlations. Checking for construct validity. Do questions measure the same dimension?. For use between or within a test. Identify items which cluster together.