Research
We study the marine bryozoan Bugula neritina as a model system because it’s experimental tractability allows us to address questions that are prohibitively challenging to answer in most other species. We rear bryozoans in the lab across generations, create experimental crosses, determine paternity and relatedness using genetic markers, and outplant colonies to the field. In the field, we measure dispersal kernels directly, and can estimate reasonable components of fitness in the field.
Theme 1: Evolution of dispersal, mating systems, and kin interactions
We are interested in why different species, and different individuals within the same species, exhibit enormous variation in both their patterns of larval dispersal and mating systems. Dispersal (any movement with potential consequences for gene flow) is an important way that populations avoid extinction, and it mediates the capacity for populations to adapt to changing conditions. Most populations within a species are not well mixed, and restricted or stochastic dispersal can enhance genetic differentiation among populations and coancestry within them. Dispersal influences the genetic relatedness between competitors and mates, which influences the evolution of resource use, reproductive strategies, and who mates with whom. Competition and mating with kin can also influence selection on dispersal. We study how selection on dispersal traits influences selection of mating systems, and vice versa. This work is funded by a grant from NSF.
Corals from the genus Pocillopora spp. on the fore reef of Moorea, French Polynesia. This genus contains several morphologically-cryptic species that we identify genetically.
Theme 2: Coral ecology and evolution
Genetic diversity and resilience of cryptic species in the genus Pocillopora.
We are studying the ecological and evolutionary differences among morphologically similar, but genetically divergent, species of corals. Corals in the genus Pocillopora (which dominate many reefs in the Indo-Pacific) can look similar to one another and some are often lumped together as one ‘species’ or misidentified on the basis of morphology. We now know that this genus contains multiple genetically divergent and evolutionarily distinct lineages that are ‘hidden’ by morphological similarity and plasticity. However, the ecological and evolutionary consequences of this hidden diversity for coral resilience are unclear at present. On the one hand, such hidden diversity could heighten the risk of extinction because, instead of one large morphologically similar population, there is actually several much smaller populations of different species (that are only identified genetically). On the other hand, such hidden diversity could provide a previously unrecognized portfolio in the capacity of the genus (and the ecological functions it provides) to recover and reorganize after unpredictable environmental changes. We are currently testing these broad predictions. We have discovered that multiple genetically distinct lineages of Pocillopora spp. co-occur at Mo’orea, in French Polynesia. This project combines genetics, field surveys of corals, and size-structured models of population dynamics and connectivity. It is funded by a grant from NSF and being done in collaboration with Prof. Peter Edmunds at California State University Northridge.
Size-dependent stress responses of corals
We are interested in why coral colonies of the same or similar species exhibit different responses to stress (such as why bleaching mortality apparently affected larger corals more than smaller corals at Mo’orea in 2019). In collaboration with Prof. Peter Edmunds at California State University Northridge, we combine mesocosm experiments and field surveys on corals at Mo’orea (French Polynesia) to estimate how growth and physiological rates are dependent on coral size and are modified by the complexities of how 3-dimensional growth forms interact with water flow, temperature, and pH conditions. We are also interested in ‘scaling up’ the results from experiments on small coral fragments to predict how whole coral colonies, populations, or communities respond in the field.