In a pinch: the response of ghost crab (Ocypode sp.) population dynamics to seasonal rainfall on K’gari

Ghost crabs (Ocypode spp.) are highly important bioindicator species which can be used as a reference to infer the health of coastal ecosystems. The sandy shore systems they inhabit are by default inconstant and vulnerable to change due to climate change. Although sea level rise, increases in temperature, and ocean acidification are indisputably important topics for research, the effects of precipitation shifts on these ecosystems are comparatively understudied. To fill this gap in current knowledge, we investigated how seasonal precipitation patterns affect the ecology and population dynamics of Ocypode sp. on K’gari, Australia, and how we can use that knowledge to infer the health of the ecosystem. Using information from a long-term dataset, we found significant correlations between summer precipitation and Ocypode sp. abundance and size, using burrow counts and burrow size as a proxy for population characteristics. The relationship between summer precipitation and burrow abundance was positive (adjusted-R2: 0.6269; p-value: 0.001306) while the relationship between summer precipitation and burrow size was negative (adjusted-R2: 0.5394; p-value: 0.003937). This has significant implications for future populations, with the expected simultaneous drop in total precipitation, but rise in downpour intensity, bringing species’ resilience into question. Further research could endeavour to further understand these variables which drive population trends, to further inform adaptive coastal management efforts.