From Disturbance to Recovery: Unveiling the Role of Goats and Ecological Drivers on Vegetation Dynamics of Trindade Island, South Atlantic, Brazil

ABSTRACT Aims Islands harbor crucial ecosystems that face expressive threats from invasive species, including goats, which have dramatically altered the vegetation dynamics of Trindade Island since their introduction in the 1700s. This study aimed to assess the effects of goats, as a primary biotic factor, alongside many abiotic factors influencing vegetation dynamics over time. Location Trindade Island, South Atlantic Ocean. Methods We analyzed vegetation cover changes from 1994 to 2024 using remote sensing data. We also evaluated the relationship between the Normalized Difference Vegetation Index (NDVI) and vegetation cover, and compared vegetation data obtained from fieldwork and remote sensing for 1994 and 2010. Results A supervised classification approach was applied to identify vegetation types, achieving an overall accuracy of 89% and a Kappa coefficient of 0.8. The NDVI analysis explained 77% of the variation in vegetation cover, revealing increases in forest (65.06 ha) and grassland (325.14 ha) by 2024. No significant differences were found between fieldwork and remote sensing data ( p > 0.05) for the earlier years analyzed. Although goats had a notable impact on vegetation ( D 2 ≥ 0.75), their influence was amplified by abiotic factors, producing statistically significant correlations ( D 2 ≥ 0.91) in generalized linear models. Incorporating both biotic and abiotic variables yielded models with higher explanatory power. Conclusions Our findings underscore the complex interplay between goats and abiotic factors shaping vegetation dynamics on Trindade Island. The study highlights the necessity of targeted conservation strategies to mitigate the impact of invasive species on island ecosystems.