My dumb question of the day:
If two thirds of the beach (upper and middle) is a barren wasteland, won't the
lower third eventually be affected by this "dead zone"?  Isn't the overall
health of a beach and the diversity of its organisms crucial to the survival of
all?
Mary~

Don Barclay wrote:

> 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
> >