UC Santa Cruz
Linking ecology, restoration science, and mitigation policy to guide management of rocky intertidal habitats affected by oil spills
- Author(s): de Nesnera, Kristin
- Advisor(s): Raimondi, Peter T.
- et al.
Solving the environmental problems created by the increasing impact of humans on our planet will require a collaborative effort between scientists, practitioners, and policymakers. In this dissertation, I provide an example of how ecologists can contribute to and benefit from environmental problem solving. I focus on rocky intertidal habitats along the coast of central California (USA), which have high levels of biological diversity and provide a rich environment for education, research, and recreation. These habitats are negatively affected by a number of anthropogenic activities and, as a result, there is a growing interest in restoration strategies, particularly for addressing the impacts of oil spills.
In the following chapters, I explore connections between ecological concepts, restoration science, and mitigation policy to guide management of rocky intertidal habitats. In my first data chapter, I experimentally test the success and benefits of using adult mussel transplants to restore mussel bed communities following disturbance events. Results show mussel transplants provide restoration benefits in areas where recovery is slow but that these benefits are limited by local mussel recruitment dynamics and likely many other environmental and biological characteristics. In my second data chapter, I examine the importance of positive species interactions (i.e. facilitation) during the mussel recruitment stage. These interactions have not been well-described and may provide important insights for mussel bed restoration. I use a combination of field surveys and experiments to evaluate how environmental stress, mussel ontogeny, and organismal movement interact to determine the importance of facilitation during mussel recruitment. I show these interactions shift from neutral to positive with increasing tidal elevation and that ontogenetic shifts in recruit survival and growth modify interactions with different facilitator species. This suggests mussels may move between multiple facilitators throughout the juvenile stage. In the third data chapter, I examine and challenge the mitigation policy and science guiding compensatory restoration of rocky intertidal habitats following oil spills. I do this by reviewing Natural Resource Damage Assessment (NRDA) cases for oil spills in California. I summarize NRDA documentation and show, while tools for injury assessment in rocky intertidal habitats have increased in recent decades, there remain few proposed restoration projects to compensate the public for these injuries. I suggest a more cooperative and flexible approach will be needed to advance compensatory restoration in marine habitats. Finally, I conclude by discussing the key insights from this work and future research directions for rocky intertidal restoration and management.