Environmental factors and predator abundance predict the distribution and occurrence of two sympatric urchin species at Ningaloo Reef, Western Australia

Two sympatric urchin species, Echinometra mathaei and Echinostrephus molaris, exhibit distinct distribution patterns at Ningaloo Reef, driven by environmental factors and predation. E. mathaei's presence is linked to algal cover, habitat complexity, and lower predator abundance, suggesting foraging behavior and predation pressure shape its distribution. Conversely, E. molaris is influenced more by hydrodynamics and regional variation, reflecting its feeding strategy and morphological adaptations. These findings highlight how species with similar ecological roles can coexist through non-overlapping feeding preferences and behavioral differences, even in intact reef systems like Ningaloo Marine Park.

Westlake, E. L., Bessey, C., Fisher, R., Thomson, D. P., & Haywood, M. D. E. (2021). Environmental factors and predator abundance predict the distribution and occurrence of two sympatric urchin species at Ningaloo Reef, Western Australia. Marine and Freshwater Research, 72(12), 1711–1721. https://doi.org/10.1071/mf21091