UC Davis

Empirical and theoretical evidence have shown us that ecological systems present a variety of different complex dynamics such as alternative stable states, chaotic dynamics, or long transient dynamics. One of these ecosystems with complex dynamics is the rocky reefs in temperate coastal waters. These rocky reefs exhibit different alternative stable states, of which the kelp forest and urchin barrens are the most studied. Kelp forests generally are highly productive and diverse ecosystems, whereas urchin barrens generally are not. This has made the question of how to manage these ecosystems to preserve current kelp forests an important one. Furthermore, we can use mathematical models to provide important and relevant information for management.In my dissertation, I use mathematical models to explore the complex dynamics that could arise in the kelp forest ecosystem. I focus most of my work on the question of when can kelp spread (i.e. have a positive growth rate at low population densities). I start my dissertation studying how ecosystem engineers' (of which kelp populations are an example) interaction with their environment affect their spread capabilities. Then I explore the possibility of the alternative stable states we observe in rocky reefs are long transients, in which kelp spread would always be feasible in a multi-decadal time scale. Finally, I use a spatially explicit model to explore the question of, when kelp is able to spread in the short time scale, what management strategies can enhance the rate at which it spreads.