Thus, the direct impact of the two trematode species on their cockle hosts has cascading effects extending to the entire intertidal community.
Secondly, the otherwise smooth mudflat surface will have greater heterogeneity, with surface-stranded cockles providing refuges and attachment substrate for other organisms.
In concert, these interactions may cause the foot of heavily infected cockles to be literally immobilized.
We compared the relative distribution of the two echinostome species among different locations in the foot and in the rest of the cockle.
Results indicate that these two species are ecological equivalents, and their combined numbers determine how the cockle population is affected.
The data are from three cockles per site; total numbers of metacercariae of both species are given in the figure.
Several epibiotic, or fouling, organisms use cockle shells as attachment substrates and even compete for space in areas where they are abundant.
The final hosts are oystercatchers that feed on the cockles during low tide.
