Historical reconstruction of human-induced changes in U.S. estuaries

Abstract

Estuaries are vital ecosystems that have sustained human and marine life since earliest times. Yet, no other part of the ocean has been so fundamentally shaped by human activities. Understanding the magnitude, drivers and consequences of past changes is essential to determine current trends and realistic management goals. This review provides a detailed account of human-induced changes in Massachusetts, Delaware, Chesapeake, Galveston and San Francisco Bays and Pamlico Sound. Native Americans have lived off these estuaries for millennia, yet left few signs of local resource depletion. European colonisation, commercialisation and industrialisation dramatically depleted and degraded valuable species, habitats and water quality. Exploitation and habitat loss were the main factors depleting 95% of valued species, with 35% being rare and 3% extirpated. Twentieth century conservation efforts enabled 10% of species to recover. Such profound changes in species diversity have altered the structure and functions of estuarine ecosystems as well as their services for human well-being. Thus, undesirable health risks and societal costs have increased over past decades. Protecting and restoring the diversity and vitality of estuaries will enhance their resilience towards current and future disturbances, yet require better governance of these often-neglected ecosystems. Their documented historical richness and essential role for marine life and people may increase the necessary awareness and appreciation.