the social sciences also use many of these methods. At the core of all the methods is
the exploration and quantification of the effects of the explanatory or environmental
variables on the observed dependent variables. ECOM is focused on the analysis of
ecological data so the dependent variables are termed biological variables and would
typically be an array of species abundances in different samples. The environmental
data set comprises observations of the explanatory variables for these samples and
would typically hold information on physical variables such as temperature, salinity,
altitude, nutrient status etc. However, it may be that the independent variables are
themselves biological variables. For example, the insect community might be
determined by a variables that measures the density of the tree canopy.
Data can be organised using Windows programs such as Microsoft Excel and the
output from ECOM is displayed, exported and printed using standard Windows
techniques. The result is a program that is easily learned and used by both students
and professional ecologists. It is particularly useful for ecological teaching because it
allows students to quickly enter data, try different transformations and explore a
range of methods within a familiar Windows setting.
The user supplies two input data sets holding the biological and physical data for the
samples (sites) respectively. These data are arranged as two dimensional arrays. In
ecology, it is usual for the samples, which are normally collected from set localities
and may be called, for example, quadrats or stations, to form the columns. The
variables for each sample are the rows and, in the case of the biological data,
comprise the numbers of each species or other taxon observed. The environmental
data may be either continuous variables such as pH, temperature or current speed, or
binary variables such as soil or treatment type which are scored as either a 0 or 1.
ECOM complements CAP (Community Analysis Package) also produced by PISCES
Conservation, which offers a range of techniques that only require biological data to
undertake the ordination or classification.
ECOM uses the same data structure as CAP and Species Diversity and Richness II,
which calculates a wide range of diversity and species richness measures. Together,
ECOM, CAP and Species Diversity and Richness II offer an extensive range of methods
for the analysis of ecological communities.
Start ECOM in the normal Windows fashion either by clicking on the program icon or
by selecting the program via the Start button.
Along the top bar are a number of pull down menus. These work in the same way as
standard Windows programs.
File: To create, open, save, export and print data.
Biological File: To select the file to open for the biological data.
Environmental File: To select the file to open for the environmental data.
Edit: To cut copy and paste to and from the active window and set the decimal
points and precision of the display
Ordination: To select the ordination methods
Variable Selection: To run a Redundancy or Correspondence analysis for selection of
the most influential variables.
Randomization: To run a Monte Carlo randomization on the data.
Regression: To select the multiple regression method.
Help: to enter the Help system and select the about box.
Copyright 2004 PISCES Conservation Ltd