I hesitate to make this comment, because continuing the myth of
mature being more diverse might help the cause of preserving old-growth
forests. However, note the "intermediate disturbance hypothesis", which
holds that habitats with an intermediate level of disturbance will have
more species (see any ecology text written after 1980).
   What good are old-growth forests, you ask? Some species are
restricted to mature habitats. If you wish to preserve those species,
you must preserve mature habitats. But if you seek to maximize local
diversity (possibly excluding obligate old-growth species), then choose
an area of intermediate disturbance. For practical purposes, nearly
every forest in the eastern USA has been logged in the last 250 years,
so seeking the least disturbed habitat you can find will probably get
you a good number of species.
   Of course, not every land snail species is restricted to forests.
Forest faunas, in my experience, tend to be more abundant. But many
species occur also or exclusively outside of forests.

Timothy A. Pearce, Ph.D., Asst. Curator & Head, Section of Mollusks
Carnegie Museum of Natural History
4400 Forbes Ave, Pittsburgh, PA 15213-4080, USA
ph 412-622-1916; fax 412-622-8837; [log in to unmask]
www.carnegiemnh.org/mollusks/index.htm

-----Original Message-----
Date:    Fri, 30 Nov 2007 10:47:19 -0400
From:    Ross Mayhew <[log in to unmask]>
Subject: Re: snailing in Chicago

Landsnails are most diverse in "mature" ecosystems, where species have
established themselves over thousands of years in a setting that is in a
state of relative equillibrium. In disturbed systems or ones being
re-established (restoration projects or systems which have been left to
regenerate by themselves), most of the indiginous species will be
absent, and one will typically find mainly "weedy" species which move
into disturbed settings agressively - "colonizers". In most localities
on the planet now, a high percentage of these adventurous species will
be introduced from elsewhere - for example, most of the common weeds in
North America (such as dandylions and "Queen Ann's Lace" (wild carrots))
are European in origin. It should be noted that it typically takes
hundreds of years for most natural systems to regain their previous
levels of biodiversity - depending upon such factors as the complexity
of the system and the availablity of replacement stock for the species
most suited to them. SO, in the Chicago area or anywhere else for that
matter, the trick to good land-snailing is to seek out the most mature
ecosystems and check out all the likely habitats for the critters one is
seeking!! For shell collectors, this would include leaf litter, under
old logs and rocks, areas where there is a lot of limestone or other
good sources of calcium carbonate, on grass, bushes and other vegetation
in the early morning or after a rain..... // I have no knowledge of
where to find mature natural systems in the Chicago region: best to
check with the local museum of natural history!!

 From a sunny, reasoably warm day in the Timberlea corner of New
Scotland, Ross Mayhew.
( http://www.schnr-specimen-shells.com/ - Seashells and Landsnails to
write home about!! )


Alex Menez <[log in to unmask]> wrote:
>
> Dear all
>
> I'm going to Chicago in a couple of weeks. Anyone have info on good
> land snailing locations, or any info re literature?
>
> Thanks
>
> Alex Menez

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