Casu Daniela, Ceccherelli Giulia, Curini-Galletti Marco, Castelli Alberto
Dipartimento di Scienze dell'Uomo e dell'Ambiente, University of Pisa, via Volta 6, I-56126 Pisa, Italy.
Mar Environ Res. 2006 Jul;62(1):15-32. doi: 10.1016/j.marenvres.2006.02.004. Epub 2006 Feb 28.
The effect of human trampling on the abundance of small invertebrates inhabiting rocky shallow bottoms was studied at Asinara Island MPA. To this aim we have conducted two experiments. The first was a quantitative study and tested the hypothesis that small invertebrates are more abundant at no-entry locations than at the location visited by tourists through time (before, during and after tourist season). The second was a manipulative experiment and tested the hypothesis that the abundance of small invertebrates is indirectly related to experimental trampling intensities. The effect due to tourist visitation was not highlighted on overall assemblages, suggesting that present seasonal tourist load at the MPA does not cause a significantly negative effect on the zoobenthic community studied. Although tourists exhibited trampling activity at the visited location, none of taxa examined showed a significant lower abundance during and strictly after the end of seasonal tourism peak in the visited location, rather than at control locations. However, results obtained with the second experiment suggested that the effects of different experimental trampling intensities on small invertebrates were variable among taxa. The experimental trampling caused immediate declines in the density of tanaids, nematodes, acari, bivalves, gammarids, echinoderms, isopods, and harpacticoids. For some of these taxa a recovery in abundance was observed within one month. This kind of data may offer important information to estimate the number of visitors compatible with the sensitivity of zoobenthic assemblages, and may substantially contribute to appropriate MPA management.
在阿西纳拉岛海洋保护区研究了人类踩踏对栖息于岩石浅海底部小型无脊椎动物数量的影响。为此，我们进行了两项实验。第一项是定量研究，检验了以下假设：随着时间推移（旅游季节之前、期间和之后），小型无脊椎动物在禁止进入区域的数量比游客到访区域更多。第二项是操纵性实验，检验了以下假设：小型无脊椎动物的数量与实验踩踏强度间接相关。游客到访对整体群落的影响未凸显出来，这表明该海洋保护区目前的季节性游客量对所研究的底栖动物群落不会造成显著负面影响。尽管游客在到访区域表现出踩踏行为，但在所检查的分类群中，没有一个在到访区域季节性旅游高峰期期间及刚结束后显示出比对照区域明显更低的数量。然而，第二项实验的结果表明，不同实验踩踏强度对小型无脊椎动物的影响在不同分类群中有所不同。实验踩踏导致异足类、线虫、螨类、双壳类、钩虾、棘皮动物、等足类和猛水蚤类的密度立即下降。对于其中一些分类群，在一个月内观察到数量有所恢复。这类数据可为估计与底栖动物群落敏感性相适应的游客数量提供重要信息，并可能对海洋保护区的适当管理做出重大贡献。
