RLQ

From: John Stark0+ (john@environment.cawthron.org.nz)
Date: Fri Aug 07 1998 - 03:56:55 MET DST


I'm trying to understand the RLQ analysis by running it using the
AVIURB data set as presented by Doledec et al. 1996 (Environmental
and Ecological Statistics 3:143-166). I am using the WIndows 95
version.

With reference to the above paper, I have managed to figure out where
all the numbers in Table 4(b) come from (although I'm not sure that
I understand what they all mean). I have also produced the
equivalent of Fig. 3 except that I have been unable to determine how
to get the lines joining the sites (black squares) to the appropriate
environmental variable code ( a or p for 10 variables, and a - h for
veg. cover). I assume it has something to do with the "Centers File"
as requested by the ScatterClass.Stars module. I can draw lines from
the origin to each site but not between the sites and the
environmental variables. Is there a file produced in the analysis
that tells me which sites connect with which environmental
categories?

I note in the ADE documentation the use of the ADE.old and Quickbasic
modules - presumably only on the Apple Mac. Is the Windows 95
version limited by comparison with the Mac version?

How does one produce figures like Fig 6 - 9 using ADE? If the
graphics require external programmes, that's fine, but what files
contain the data that are plotted, and how are these created by
the analysis?

Any specific assistance would be appreciated, as we have data from a
longitudinal survey of freshwater invertebrates (at 15 sites on 3
occasions) down a river, including some environmental data and
species traits, that could be ideal fro RLQ analysis (if only we
could get it to produce the nice graphs).

**************************************************
Dr John D. Stark
Manager, Consulting Group
Senior Consultant / Research Scientist
Cawthron Institute
Private Bag 2
98 Halifax St East
Nelson
New Zealand

+64 3 548 2319 (phone)
+64 3 546 9464 (FAX)
john@environment.cawthron.org.nz
http://www.cawthron.org.nz/
**************************************************



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