|Limpet shells overgrown by ascidians and bryozoans|
I made a few interesting observations. First, the limpets were overgrown by other organisms, more so than I had expected. I saw some overgrowth last year, but only on very small individuals (I only got very small individuals on my panels last year). I wasn't sure how the larger adults would fare with overgrowth, but they seem just as susceptible to it as the younger limpets. The shells I had glued to the panels were completely covered in fauna, and the live individuals had plenty of colonists too. I was fascinated to see that they could still move around with such heavy fouling.
|One of my fouling panels with live adult limpets. Notice|
the large halo around the four individuals in the bottom
It may sound like my experiment disproves my hypothesis, and in the strictest sense, that is true. But like all things in biology, sometimes the result you get is a matter of scale. On the scale of a few square centimeters around the limpet, yes, the bulldozing does have a significant effect. On the scale of a whole panel, though, it does not. I'm thinking about ways to analyze my data to demonstrate this difference.
The last thing I noticed is that even though there were halos around each of the limpets, the empty space didn't stay empty for long. It was recolonized by new recruits that could eventually grow to cover the space. Limpet bulldozing may not be so much a matter of empty v. overgrown space, but rather the bulldozing allows for space to be cleared and recolonized over and over again. This turnover in the community will certainly have an effect as time goes on, especially as seasons change and new organisms become ready to recruit to empty space. I suspect limpet bulldozing may lead to more heterogenous communities.
After counting all the organisms on the panels, I reset the experiment. I replaced any limpets that had fallen off and returned all panels to their rightful places on the dock. I will return in a few more weeks to see how the community has changed!