Investigating climate change and nutrient pollution effects on Drupella rugosa coral reef destruction in Koh-Tao, Thailand

The introduction and proliferation of invasive species in coral reef ecosystems play a pivotal role as significant contributors to ecological disturbance. These invasive species pose specific threats to the delicate equilibrium of coral reef health by disrupting nutrient cycling, modifying community structure, applying selective pressure on essential coral species, leading to ecosystem degradation. Embarking on an exploration of ecological intricacies, this study focuses on the invasive coral-feeding snail Drupella rugosa in Koh Tao and aims to explore how environmental variables affect its abundance. Although prior research elucidated the impacts of environmental stressors on coral reef degradation, methodological limitations and gaps in understanding the specific effects of nutrient pollution necessitate a more comprehensive investigation. Therefore, this study intends to fill these gaps by employing extensive linear regression analyses, between 2010-2022, among the abundance of D. rugosa and its complex relationship with the environmental variables of salinity, temperature, phosphate (PO4), nitrate (NO3-), dissolved oxygen (DO), and partial pressure of carbon dioxide (pCO2). The findings of this research reveal that Drupella abundance exhibits a significant positive correlation with pCO2, being the most substantial influencer (ANOVA, p < 0.001, F = 25.56, df = 8, R2 = 0.71), and salinity (ANOVA, p < 0.05, F = 6.557, df = 8, R2 = 0.3572), indicating that as variables rise, species abundance increases. Conversely, there is a negative correlation between Drupella abundance and PO4, as highlighted by the significant ANOVA results (p < 0.05, F = 6.42, df = 9, R2 = -0.3301), suggesting that an increase in phosphate levels leads to a decrease in D. rugosa abundance. This paper underscores the importance of understanding the specific vulnerabilities of coral-associated species, like D. rugosa, offering insights that could inform future conservation efforts aimed at protecting coral reef ecosystems from the compounded threats of nutrient pollution and climate change.