Crustose coralline algae exhibit complex responses to breakage under current and future climate scenarios.

Rising pressures from local and global stressors on marine benthic habitats require understanding of their effects on habitat forming species like Crustose Coralline Algae (CCA), which play a crucial role in ecosystem diversity and structure. Here, the impact of mechanical damage and warming on the CCA species Lithophyllum stictiforme was investigated in the Mediterranean Sea using a manipulative field transplant experiment that takes advantage of temperature variations between depths of 35 m and 15 m as proxies for current and future climate scenarios. A significant effect of mechanical damage and warming on the growth angle of the thalli was detected, while no interactive effects on the other biological traits were observed. Higher temperatures increased Mg/Ca ratio in untouched thalli, but mechanical damage disrupted this pattern in broken samples. Overall, our findings highlight the resilience of thalli to warming but demonstrate suffering from mechanical damage, underlining the need for effective benthic habitat management.