Spatiotemporal Changes in Odonata Assemblages in Freshwater and Coastal Habitats Associated With the Onset of the Operation of an Industrial‐Mining Complex in the Eastern Amazon

ABSTRACT Industrial‐mining expansion is reshaping ecological processes across tropical landscapes at an unprecedented rate, yet its consequences to aquatic biodiversity remain insufficiently quantified. We used a before‐after repeated‐measures design to assess temporal changes in Odonata assemblages following the onset of operations at an industrial‐mining complex in streams and mangroves along a gradient of potential spatial exposure in the eastern Amazon (State of Pará, northern Brazil). Adult Odonata were collected at three sites from each habitat type (located at increasing distances from the industrial‐mining complex) across multiple quarters of the regional dry season, both in the year preceding and in the first year of the operation of the industrial‐mining complex. In streams, Odonata alpha diversity (richness and Shannon diversity) consistently decreased after the onset of the operation and was accompanied by marked and variable shifts in composition. Particularly, the abundance of disturbance‐tolerant Anisoptera taxa decreased near the complex, while the abundance of specialist Zygoptera taxa decreased in all streams after the onset of operation. Across mangroves, Odonata assemblages varied primarily with spatial distance from the complex and showed weaker temporal changes in composition between operational phases. In particular, Odonata assemblages in the mangroves near the industrial‐mining complex exhibited greater compositional variation than in mangroves farther away. Such responses highlight the habitat‐specific sensitivity of Odonata to land‐use changes, with stream assemblages appearing more vulnerable to industrial‐mining impacts than mangroves. Our findings underscore the importance of incorporating multiple habitat types and explicit spatial gradients into environmental impact assessments and reinforce the value of Odonata as bioindicators of aquatic ecosystem health in tropical forest landscapes in the Global South.