PhD Project 1: Mechanisms facilitating or inhibiting co

PhD Project 1: Mechanisms facilitating or inhibiting co-existence among estuarine
foundation species
Marine foundation species, such as seagrass, seaweeds and reef-forming bivalves can control
habitat-structure, productivity, and biodiversity in near-shore ecosystems. To manage marine
systems successfully it is critical to understand where and when these foundation species coexist, and also if one type can outcompete another. Using estuaries as a marine model system,
this project will test mechanisms that affect the direction and magnitudes of interaction
strength between foundation species, and how the interactions are modified by environmental
gradients, external bottom up and top-down forces, and human stressors.
In estuaries throughout New Zealand, slow growing seagrasses and reef-forming bivalves
often co-exist with ephemeral fast-growing seaweeds, which are increasingly dominant. The
PhD student will have an opportunity to test and quantify (1) competition coefficients
between these archetypal foundation species, (2) if thresholds exist where the system changes
to single-species dominance, (3) environmental conditions that facilitate or inhibit coexistence, (4) how human stressors, such as eutrophication and climate changes, change
competitive interactions, and (5) how ecosystem functions changes as the relative importance
of different foundation species changes. These goals will be addressed combining field and
laboratory experiments, field surveys and remote-sensing analyses, literature reviews, and
spatial modelling (GIS included).