species diversity gradient problem

[Stein, David]

Hi Peter:

We had the same problem looking at deep water fishes.  There are a
number of different ways to approach this problem.  See Pearcy, Stein,
and Carney 1982 Biological Oceanography 1(4):375-427.  Also look at
Haedrich, Rowe, and Polloni 1975 Journal of Marine Research
33(2):191-212.  If you want to discuss this further I will be happy to
do so offline.

Cheers
David Stein

> ----------
> From:         Peter Schuchert[SMTP:peter.schuchert at MHN.VILLE-GE.CH]
> Reply To:     Peter Schuchert
> Sent:         Tuesday, June 22, 1999 2:14 AM
> To:   Multiple recipients of list TAXACOM
> Subject:      species diversity gradient problem
>
> dear collegues
> could anyone give me some hints on publications
> with studies comparable to my case decribed below?
>
> I have identified all marine hydroids down to 2400 m depth from
> a collection made in a defined region. I would now like to
> know how species diversity decreases with depth.
>
> However, there are two ways of analysing this, and I don't know
> which one is more appropriate.
>
> First, I can define equal depth intervals of 100 m and then
> count the species present in the individual intervals. But this will
> lead to unequal sample sizes (unequal search effort).
>
> The other solution is to define depth intervals which have
> the same number of samples taken. This will lead to rather unequal
> intervals.
>
> I assume, that species diversity is both dependent on
> search effort and area (= depth interval).
>
> Both approaches give a decreasing species number with depth,
> but the first method gives a much more dramatic result.
>
> Any idea?
> cheers,
> Peter
>
> Dr. Peter Schuchert
> Museum of Natural History
> Dept. of Invertebrates
> 1, route de Malagnou
> CH-1208 Geneva
> Switzerland
>
> fax 0041 22 418 63 01
> http://www.ville-ge.ch/musinfo/mhng/index.htm
>