Hi all,

I read the referenced Texas A&M case study, and it seemed
like it mostly stated the obvious:  that things don't live where they
are likely to be run over by cars.  You'd think that wouldn't require
a very extensive study to figure out.  However, it did say that  in the
lower beach areas, i.e. where Donax would live, the number of
animals appeared similar on both the restricted beaches and the
ones where driving is permitted.

This is what I would have predicted, since most of the Donax
population won't be spending a lot of time up on the areas where
they are likely to become road kill.  The study was about the
impact of vehicular traffic on the beach, and made some valid
observations about reduction in the number of animals in the
middle and upper beach areas.  However, the reference to the
Donax variabilis population is a little confusing.  It says,
"Seasonally, the small clam Donax variabilis was abundant,"
then immediately follows that by saying that the lower beach
areas had similar numbers of organisms, without further comment.
I would guess that the seasonal variations in the population, along
with the other factors that were mentioned in passing (oil spills,
industrial pollutants, toxic algal blooms, hurricanes, storms, and
diversion of sand by structures that cut off the flow of replenishing
sand) would be a lot more likely to negatively impact the
availability of Donax than driving on the beach.  If you were
collecting sand flies, that might be a totally different matter.

Cheers,


Don


>    Automobile Traffic on Texas Beaches
>    http://www.mhhe.com/biosci/pae/marinebiology/casestudies/case_08.mhtml
>