The Wolf Based Trophic Cascade in the Olympic Peninsula: Ecological Impacts on Salmon, Mollusks, and Beyond

The Olympic Peninsula of Washington State, USA, is an ecologically diverse region that has undergone significant changes due to anthropogenic influences such as the removal of gray wolves (Canis lupus occidentalis). This trophic cascade has led to a decline in biodiversity, the loss of important habitat for aquatic species, and significant cultural impacts on indigenous tribes such as the Quinault Indian Nation (QIN). Our study explores the impact of trophic cascades on the ecosystem of the Olympic Peninsula, focusing on the effects of the removal of wolves on the Roosevelt elk (Cervus canadensis roosevelti) population and functions of riparian zones. Our findings suggest that the removal of wolves has led to an increase in elk populations, resulting in overgrazing of riparian zones, a reduction in vegetation, and loss of salmon (Oncorhynchus spp.) spawning habitat and beaver (Castor canadensis) dam pools. This, in turn, has had a cascading effect on the entire ecosystem, leading to a decline in mollusks (Class Mollusca), limpets (Order Patellogastropoda), and phytoplankton (Division Chlorophyta) populations in the Pacific Ocean. Our study highlights the critical role that wolves play in maintaining the ecological balance and the need to protect their populations. Additionally, the QIN’s efforts to mitigate the impacts of the trophic cascade through blueback salmon (Oncorhynchus nerka) harvests and habitat restoration offer valuable insights into effective conservation strategies. Our study underscores the importance of considering the broader ecological and cultural implications of human activities in managing and protecting natural ecosystems.

Keywords:Trophic cascade; Olympic Peninsula; Apex predators; Salmon; Beaver; Indigenous communities; Biodiversity Conservation; Riparian zones; Ecosystem resilience; Cultural heritage; Sustainable land management

Abbreviations: Engineered Log Jams (ELJ); National Environmental Policy Act (NEPA); Quinault Indian Nation (QIN); US Bureau of Reclamation (BOR)