Eric
It sounds like your data structure is well suited for the comdyn
program at the following.
http://www.mbr-pwrc.usgs.gov/software/comdyn.shtml You can run the
program online or download it to run locally. Also, the main website
has many other specialized programs with references.
Not only will you get estimates of species richness, but it will be
able to do pairwise comparisons of treatments. You will also be able
to make pairwise comparisons of spring and non-spring data. The
whole process is based on occupancy modeling. The only drawback is
that the analysis will only compare two treatments at a time. I know
others may have better ideas to analyze things more comprehensively,
and I would love to see their ideas as well.
LaRoy Brandt
At 11:57 AM 5/12/2011, Eric North wrote:
Hello All
In an attempt to both better ensure that I'm using the
most appropriate and up-to-date analyses available, and also to provide a
bit of an exercise to point out just how many ways/opinions there are
to analyse data like this, I'd like to posit an exercise for the list. I
am in the final throes of a project that I have gathered richness and
abundance data for a community of organisms, with several treatments. I
have exhaustively sought help from others on how to best look at my
data, and have received, let's just say, an interesting number of ideas.
As such, I thought as this seems to be a very quickly evolving and
somewhat more common field, I'd like to also point out maybe to others
the most up-to-date means of crunching their numbers through feedback on
my project from the listserv.
I have abundance and richness data
for 30-some total species at 18 sites in three elevation zones (6 sites
in each zone). Each site consists of spring and non-spring habitat, for
which there were 6 samples taken in the spring habitat and 6 in the
non-spring. I also have data on litter depth, canopy cover, pillbug
presence and grazing presence. I want to see how communitites change
from the spring to the non-spring habitats within an elevation range and
also between ranges, and what effect each of the treatments contributes
to this relationship. Keep in mind nestedness with certain treatments.
As
I said, I've finished the bulk of the analyses, but thought maybe one
last effort was worthwhile. Rather the say what I've done, I'll wait to
get feedback and then see how the list thinks this jives with what they
think!
Best-
Eric
Eric North
All Things Wild Consulting
P.O. Box 254
Cable, WI 54821
928.607.3098
