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st: Ecological monitoring

From   "Graham M Smith" <>
To   <>
Subject   st: Ecological monitoring
Date   Mon, 5 Aug 2002 08:45:19 +0100

This is probably a very broad question so I will be grateful to anyone who has the time to answer. I also apologise for its length

A lot of ecological monitoring is undertaken by consultants with limited statistical abilities, even though it often involves a fairly sophisticated design. eg 10 transects with 5 sampling stations per transect, 10 samples collected from each Station, and samples collected 4 times a year for 5 years. Some of the transects might be impacted upon by development and you are trying to compare those with the ones not impacted upon. Or all transects might be impacted upon and it is a before and after type study. 

An unsophisticated  approach to this, that I have often seen done, is to aggregate the results in a manner that allows an ANOVA to be done, usually Kruskal Wallis, or if a statistician is involved - to use a mixed effects model usually in SPlus.

I have just started to read Lohr "Sampling: Design and Analysis" and discovered the facility in Stata to analyse survey sample data, which would seem to be an extremely useful tool for analysing environmental or ecological data. Yet I know of no one in the environmental/ecological field that uses Stata, or indeed programs like Sudaan. A quick poll of the professional statisticians I know (n=5)that work in ecology came up with a "never heard of Sudaan" "don't know anything about Stata" "can't see it doing anything that proper programming in S-Plus can't do"

However, I am personally still interested in exploring this further. I am not a statistician, but I am interested in the design and analysis of cost effective and robust ecological/environmental monitoring programs. I have a reasonable understanding of statistics but it falls short of writing S-Plus programs and mixed effects modelling.

Is anyone here using Stata in an ecological or environmental field (eg Pollution studies) and do the tools in Stata for analysing Survey sampling data offer something valuable to the analysis of ecological data. Not everyone has the skills or time to write an SPlus program - even if it can be done.

Any way, I would be grateful if anyone  can provide some comments on this, and improve my understanding of Stata and the use of its Survey Sampling routines.

Many thanks,

Graham Smith 

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