Bioerosion and bioprotection (bio-remodeling) is the action exerted by biota colonizing rocky shores. It represents an important component among processes responsible for shaping coastal landforms, and a clear evidence of interaction between the biosphere and the solid earth. Barnacles extensively colonize the midlittoral belt of rocky shores in the Mediterranean Basin. Previous research, mostly based on laboratory evidence, suggests that barnacles are bioprotectors, in that they protect the rock surface from different types of physical and chemical weathering. In this paper, we present the results of a field experiment carried out at different spatial scales at two study areas along the moderately energetic and microtidal coast of NW Italy. Barnacles were removed from the sandstone bedrock in replicated plots (manipulated plots) arranged according to a hierarchical spatial design. After four months rock hardness was tested on each plot with both Schmidt hammer and Equotip Piccolo devices, as well as on a corresponding number of control plots. Data were processed by means of a multifactorial analysis of variance (ANOVA). In control plots, rock hardness tested with Schmidt hammer exceeded that measured in previously manipulated plots. Testing with Equotip yielded the opposite results. This experimental evidence confirmed that barnacles play a bio-protective role in the midlittoral at sub-surficial level, while adding the key aspect that this effect is generalizable to spatial scales ranging from a few centimeters up to tens of kilometers. In addition, our results showed, for the first time, that at surface level they can simultaneously act as bioeroders, likely causing corrosion of the rock surface by fostering dissolution of the sandstone carbonate matrix.

生物侵蚀和生物保护（生物重塑）是生物群在多岩石的海岸上定居所产生的作用。它代表了负责塑造沿海地貌的过程中的重要组成部分，是生物圈与固体地球之间相互作用的明确证据。藤壶广泛地定居在地中海盆地多岩石海岸的中沿海带。先前的研究主要基于实验室证据，认为藤壶是生物保护剂，因为它们可以保护岩石表面免受不同类型的物理和化学风化作用。在本文中，我们介绍了在意大利西北部中等强度和潮汐沿海两个研究区域以不同空间尺度进行的田间试验的结果。在根据分层空间设计安排的重复样地（操纵样地）中，从藤岩基岩中除去藤壶。四个月后，使用Schmidt锤和Equotip Piccolo装置在每个样地上以及相应数量的对照样上测试了岩石硬度。数据通过方差多因素分析（ANOVA）进行处理。在对照样区中，用施密特锤测试的岩石硬度超过了先前处理过的样区中测得的硬度。用Equotip进行测试得出相反的结果。该实验证据证实，藤壶在次表层水平的中部沿海中起着生物保护作用，同时增加了这一影响可推广到几厘米至几十公里的空间尺度的关键方面。此外，我们的结果表明，