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ECOM II

Canonical Correspondence Analysis (CCA),

Redundancy Analysis (RDA)

Multiple Regression (MR).

Stepwise Regression (SR)

Researchers in other fields such as palaeontology, archaeology and the social sciences

also use many of these methods.

A particular feature of ECOM is the graphical output that enables you to quickly

visualise the complex relationships within your data set. For example, CCA output

includes plots of sample and species ordinations, environmental correlation vectors

and biplots of species arranged along individual environmental axes. All aspects of the

graphs can be altered, and printed or exported in a wide variety of formats.

The user supplies two input data sets, in a 2 D array, holding the biological and

physical data for the samples (sites) respectively. In ecology, it is usual for the

samples, which are normally collected from set localities and may be called, for

example, quadrates 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) and

Species Diversity and Richness II (SDR) which offer a range of techniques that

only require biological data to undertake the analysis.

12.3

Species Diversity and Richness II

Home page link

A program to calculate and compare species diversity, estimate total species richness

and study patterns of abundance

Species diversity and richness

 is a Windows 95/98 program designed for both the

professional ecologist and students. The methods on offer range from the familiar,

such as the calculation of various diversity indices and the fitting of common

distributions to more recently developed techniques such diversity ordering and total

species richness estimators. Together they provide a powerful suite of methods to

explore, compare and analyse community diversity. Species diversity and richness

version 2 offers considerable improvements over version 1. Existing users will

immediately note the redesigned menu system and improved graphics, data input and

printing. Probably the greatest recent improvements have been the extended range of

methods and statistical tests on offer. The program offers all the analytical tools that

a general ecologist needs for analysing and comparing the diversity of communities.

Because most users have now moved to Windows 95/98 version 2 is not available for

Windows 3.1. Version 1 of the program is supplied for 3.1 users.

Methods available within Species diversity and richness include

9 Alpha diversity indices including Shannon s, Simpson s, Fisher s  and Q statistic.

Bootstrapping of confidence intervals.

Randomization tests to compare diversity between sites.

2 diversity ordering methods.

6 methods to estimate total species richness

Rank order and species accumulation curves.

Copyright 2004  PISCES Conservation Ltd