Examining Relative Predation on Juvenile Horseshoe Crabs across Intertidal Landscapes

The composition of intertidal landscapes plays a critical role in shaping nursery functionality by influencing predation pressure on juvenile organisms. To test whether intertidal oyster reef sills reduce predation on juvenile horseshoe crabs (Limulus polyphemus; HSC) in nearby sandflat nurseries, we used tethering to compare relative predation in two intertidal landscapes: one with an oyster reef (i.e., reef site) and one without (i.e., no-reef site). Lab behavior experiments confirmed that tethered HSCs behaved similarly to untethered HSCs, ensuring field results were unbiased. Field predation trials were conducted in the Fall of 2023 and Summer of 2024, with HSCs tethered at reef and no-reef sites. Relative predation was not significantly different between habitats with and without reefs but varied with season and HSC positioning to the reef. These findings suggest that nearby oyster reefs may influence predation dynamics in adjacent nurseries, highlighting the importance of habitat connectivity in shaping juvenile benthic invertebrate survival. Understanding these interactions can inform broader conservation strategies by illustrating how the loss of structural habitats like oyster reefs may compromise the integrity of surrounding nursery areas and contribute to the degradation of intertidal landscapes.