The impact of human trampling on intertidal barnacle populations (Balanus glandula and Chthamalus fissus) at two sites along the Palos Verdes Peninsula, Los Angeles County, California.

摘要

The rocky intertidal zone at Point Fermin Marine Life Refuge (PFMLR) and Wilder's Annex (WA) in San Pedro, California, was experimentally trampled to examine the impact on barnacle populations. At each site, 12 plots containing Balanus glandula and/or Chthamalus fissus were randomly established and subjected to monthly trampling treatments of 0, 150, or 300 steps for 23 months. WA had a statistically significant decline in barnacle cover only at the 300-step treatments with a significant increase in basal diameter over all the treatments. PFMLR had a statistically significant decline in barnacle cover at all intensities; but the 150-step was most negatively affected, with no significant change in barnacle basal diameter. This was an unexpected result that was possibly caused by unaccounted-for factors. These results indicate that human trampling can significantly alter barnacle populations, but with variable outcomes among sites that may depend on barnacle species, settlement success, and location.