intertidal region of rocky shores

• desiccation stress (abiotic factor):

  species in the upper intertidal zone are exposed to air for longer periods and must tolerate higher levels of desiccation. Evidence shows that species like barnacles and limpets have adaptations such as thicker shells and the ability to close their shells tightly to retain moisture.
• temperature extremes (abiotic factor):

  the upper intertidal zone experiences greater temperature fluctuations. Organisms in this zone have adapted to withstand these extremes. For instance, some snails and limpets can survive higher temperatures by moving to shaded areas.
• salinity variations (abiotic factor):

  rainfall and evaporation can cause significant changes in salinity, especially in tide pools. Organisms in the upper intertidal zone must be able to tolerate wider range of salinities, unlike those in the lower zones where the salinity is more stable due to constant submersion
• wave action (abiotic factor):

  the physical force of waves can dislodge organisms. Species in the lower intertidal zone often exhibit adaptations like stronger attachment. For example, mussels anchor themselves to rocks.
• predation (biotic factors):

  predators often define the lower limits of prey species. For example, sea stars are significant predators of mussels and barnacles, often restricting these species to higher zones where sea stars are less effective due to exposure to air.
• competition (biotic factor):

  inter-species competition for space and resources plays a crucial role. For example, barnacles and mussels compete for space on rocks. The competitive exclusion principle suggests that the better competitor will dominate the more favorable middle zones, pushing less competitive species to upper or lower extremes.
• larval settlement and recruitment (biotic factor):

  the distribution of larvae and their settlement is influenced by water currents, which can affect the distribution of adult populations.