Ah, so you are the expert?  What is your background?  What is your expertise?  Do you have more expertise than the author of one of the papers that were referenced?  Seriously, I searched for studies of trampling on gravel/cobble beaches and could find none.  Do you know of any?  Even if you found any you would need to be careful as there is a great deal of difference between between the natural wave action in a protected wave area like the end of Eastsound and the direct exposure to winter storms that the west-side beach has being open across Griffin Bay and San Juan Channel.  It does not take an expert to see that there is a difference between the biological communities that can live on bedrock tidelands or gravel.  The referenced studies were about macroscopic life like barnacles, mussels and seaweeds.  Again, they are not relevant to the west-side beach.