Filling a gap:dynamics of space occupancy on a mussel-dominated subtropical rocky shore

摘要: The mussel Sernirnytilus algosus (Gould) often dominates the space on exposed rocky shores of subtropical South America. Dynamics occupancy was investigated in a intertidal habitat central Peru. A series colonization expenrnents and quantitative sampling musselassociated faunas were conducted to clarify interspec~f~c relationships anlong resident organisms. Spatial gaps created within S. zone colonised successively by barnacles Jehlius cirratus (Darwin) Notochtharnalus scabrosus (Darwin), gallery-building polychaete, Phragmatopoma moerchi Kinberg, mussel, algosus. rate colonisation/recruitment highest for barnacles, intermediate l? lowest There no evidence that either facilitate or inhibit colonisation later colonists Three filter-feeding taxa showed clear competitive hierarchy. competitively superior both P rnoerchi. Therefore, there are trade-offs between ability among these taxa. In addition recruitment young larvae free rock surfaces, individuals demonstrate continuous lateral migration at edge their aggregation, constantly expanding boundaries. Gaps can be closed this manner, with an average advance 1.2 cm mo-', which is comparable values estimated Mytllus californianus North American bed constitutes important range organisms, many them (particularly polychaetes) being restricted shores. Comparisons made surfaces bed. Proportions high all invertebrates found there, 67 78 % terms number 80 94 individuals. Furthermore, juveniles organisms find refuge bed, inferior nevertheless exist epizoically shells. Thus, monopolisation generally leads Increase total species richness.