Environmental Pollution and Habitat Modification Altering Behavioral and Physiological Responses of Aquatic Birds in Coastal Wetlands

Abstract

Coastal wetlands are important ecotones that suffer from heavy degradation due to anthropogenic pressures. In this paper, the interaction between the impact of pollution and modification of habitats will be analyzed in terms of changing bird behavior and physiology under these anthropogenic threats. Using a multivariate index stress approach coupled with the use of behavioral tracking data, we estimate the change in efficiency of foraging activities, timing shift in migration, as well as disruption of bird physiology, including increased stress levels caused by elevated corticosterone activity and oxidation. We find that exposure to heavy metals and acoustic pollution leads to lower average rates of foraging activities; furthermore, habitat destruction decreases the nest density on coastal wetlands. From an energy consumption perspective, we see that birds living in modified environments consume more metabolic energy to satisfy their primary physiological needs than those in pristine reference areas. In addition, it can be shown statistically that there is an association between high salinity gradients caused by changes in hydrological conditions due to climate change and low redox regulation in cells of the local waterfowl species. Such results reflect the importance of the breakdown of behavior and physiological adaptation due to rapid environmental change caused by humans. Finally, this study offers an approach that can be applied in coastal wetlands management, where microphysiological stress is shown to cause macro population losses in aquatic ecosystems.