UC Davis

As global environmental challenges intensify, understanding the multifaceted dynamics of ecosystem adaptation, as well as what constitutes effective habitat restoration, becomes paramount. The first part of this dissertation aims to understand the ecological success of habitat restoration efforts and its correlation with public perception for enhanced project outcomes and public support. Focusing on tidal marsh ecosystems, we gathered qualitative and quantitative data on public perceptions and ecological responses to restoration in Oregon, USA. Our analysis revealed an increase in hydrology scores with the number of restoration actions, while no distinct relationship emerged between restoration actions and vegetation scores. To bridge social and ecological metrics, we developed a linking matrix and found that although restorationists and the public shared similar values, community priorities often went unaddressed in project assessments. Furthermore, human perceptions and values were rarely considered in restoration evaluations. These findings highlight the need to integrate social values into restoration projects and improve communication between stakeholders.An important environmental challenge for tidal marshes is sea-level rise (SLR) and the second part of this dissertation investigates the combined effects of SLR and biological invasions on a tidal marsh cordgrass (Spartina foliosa) ecosystem. Field experiments in San Francisco Bay, CA, USA, demonstrated reduced cordgrass survival in the presence of invasive crabs, along with varying responses of benthic microalgae and macrofaunal grazers to tidal inundation. Contrary to expectations, no interactive effects between increased inundation and invasive species were observed. This highlights the importance of considering sequential or latent stressor effects on ecosystems. In light of the impending changes brought about by SLR, the final part of this dissertation explores the intricate trophic interactions between aquatic and terrestrial habitats within tidal marsh ecosystems. We simulated sea-level rise using experimental structures that increased tidal inundation and assessed changes in various ecological indicators and species responses. Cordgrass exhibited negative responses to increased inundation, likely due to oxygen limitations resulting in elevated sulfide levels. Additionally, insect responses varied with some species showing positive reactions to inundation, while others exhibited negative responses. The presence and abundance of Song Sparrows (Melospiza melodia) were influenced by elevation and year, potentially linked to alterations in S. foliosa integrity and Chironomid abundance. This underscores the importance of integrating aquatic-terrestrial connections into predictive models for sea-level rise effects and conservation strategies, offering valuable insights for proactive management and sustainable coastal planning. Collectively, these results suggest that effective restoration and adaptation strategies for tidal marsh ecosystems require a holistic approach that bridges ecological and societal considerations. Recognizing the interplay between human values, ecosystem responses to restoration, and the complexity of trophic and stressor interactions is pivotal to craft strategies that safeguard these vital ecosystems in a changing world.