Research

We study population and community dynamics in primarily coastal marine ecosystems with the goal of understanding the impacts of global change and the actions that could foster abundant wildlife and healthy ecosystems for all to enjoy. We use statistical tools, population genomics, and mathematical ecology to understand general patterns that stretch deeper in time, farther across the landscape, and across a wider range of species than would be possible with more traditional techniques. A sampling of our projects is below.

How do marine communities respond to climate change?

Climate change is not just an increase in temperature or change in environmental conditions; it’s also a velocity across the seascape as species’ preferred conditions move to new locations. While it’s clear that species distributions shift as climates change, our understanding of the mechanisms, causes, and consequences remain limited. Can all species keep up with rapid climate velocities? How does climate interact with other factors, like habitat, currents, fishing, food web dynamics, and evolution? How do individual species response scale up to entire communities?

The consequences for fisheries and the coastal towns that rely upon them are also substantial, and yet fisheries management is only just beginning to consider climate change. How do fishermen adapt to the changes, and what are the feedbacks of these coping mechanisms to the natural world? Understanding the dynamics of this coupled natural-human system will require new theory that scales from the local processes of population dynamics and species interactions to the large-scale sustainability of the system. To date, we’ve focused on North American coastal species and fisheries, building large databases of observations against which we can test broad hypotheses, as well as developing case studies, mathematical models, and field systems to explore  dynamics in more detail.

Where do baby fish go, and what are the consequences?

IMG_3255_mod_cropDispersal can drive population dynamics, range limits, and local adaptation, but a first step in understanding these processes is to understand how far organisms disperse. Using coral reef fishes (Amphiprion spp.) as a model system, we apply population genetic, modeling, and oceanographic tools to understand how far larvae move in a single generation, how this dispersal affects population dynamics and local adaptation, and how to design more effective conservation strategies given this knowledge (particularly marine protected areas). Our field work is primarily in the central Philippines, but additional collaborations have focused in Papua New Guinea.

How have species coped with catastrophic events?

A major challenge in global change ecology is to understand why some species are more likely to collapse to low abundance than others. For example, patterns of extinction risk on land usually follow a classic pattern: organisms with large body size, slow growth, and small ranges are the most vulnerable. The oceans have long been assumed to follow similar patterns, but our work has revealed that patterns are nearly the opposite: small, fast-growing species are in fact most likely to decline to low abundance in the sea. The fundamental but surprising differences between land and sea reflect substantial differences in the history of human influence, with habitat transformation driving much of the extinction risk on land, while overfishing remains a primary driver in the ocean. The approaches we use tend to be either comparative (integrating information on taxonomy, traits, environment, and human impacts across hundreds of species) or genomic (reconstructing population histories using DNA, ancient DNA, and Approximate Bayesian Computation).

How do we measure the value of clean water, abundant wildlife, and protection from storms?

Guerryetal2012Fig4iFor centuries, our societies have been better off thanks to a wide range of benefits provided by coastal ecosystems. These include obvious goods like food from fishing and aquaculture, but also more subtle services like coastal protection from mangroves, or newly emerging services like wave energy. While we can list these benefits qualitatively, understanding their magnitude has been much more elusive. How do human activities alter these benefits? Can we manage coastal ecosystems for a wide range of benefits, or are there important tradeoffs? How do we predict the goods and services we’ll get from a natural or a disturbed seascape?