Research Projects Although I am interested in a variety of ecological questions, there have been two major themes to my research. The first is understanding how marine intertidal herbivores structure seaweed communities, including selecting for seaweed defenses and altering species composition and diversity. The second major component of my research is understanding the drivers of biodiversity change and how variation in biodiversity affects ecosystem processes. Below are some of my current and past research projects.
Current Projects Ecological Impacts of Mangrove Expansion in Salt Marshes of the Northern Gulf of Mexico In the Northern Gulf of Mexico, increased temperatures and decreased freeze events have led to the expansion of black mangroves (Avicennia germinans) in salt marsh habitats. This increase in woody vegetation may affect benthic salt marsh herbivores through changes to both the physical habitat structure and their food resources. For my postdoctoral research, I investigated how mangrove size influences 1) herbivore interactions with salt marsh vegetation and 2) predator-prey interactions in Northwest Florida and Southeast Texas.
Past Projects Factors that Affect the Strength of Inducible Defenses in Intertidal Seaweeds Following grazing damage, a variety of seaweed species induce defenses and become less palatable to other herbivores. Although these responses appear to be common in marine systems, we know little about their ecological importance in natural communities. For instance, in diverse herbivore assemblages, competitive, indirect, and facilitative interactions may work in combination to alter net herbivore effects. Thus, for my dissertation research (Jones 2016), I investigated factors that affect the strength and sensitivity of inducible defenses, including variation in herbivore diversity, identity (Jones and Long 2017), and abundance (Jones and Long 2018).
Influences of Non-random Biodiversity Change on Marine Ecosystem Functioning PI's: Matthew Bracken and Susan Williams A variety of biotic and abiotic factors can influence species diversity in non-random ways, in turn, altering ecosystem processes. For this project, we manipulated abiotic stress, herbivores, and nutrients in a rocky intertidal system in Northern California to determine how these factors alter seaweed diversity (Williams et al. 2013). We then assessed how these non-random changes in diversity influenced seaweed growth, photosynthesis, and nutrient uptake rates (Bracken et al. 2011, Bracken and Williams 2013).
Impacts of Habitat-Modifying Invasive Macroalgae on Epiphytic Algal Communities As new ecological interactions are established with the introduction of an invasive species, both competition and facilitation may be important mechanisms for controlling the species composition within communities. Thus, while some native species may be displaced in the presence of an invader, the abundance and diversity of other native species may be enhanced through these new interactions. For my masters thesis research (Jones and Thornber 2010), I investigated the role of habitat-forming invasive macroalgae for epiphytic algal communities by conducting monthly field surveys of epiphyte abundance, richness, and diversity on two native and two invasive host species. I also examined potential mechanisms for differences in epiphyte composition among hosts using mimic experiments of secondary structure and feeding assays with the herbivorous snail Lacuna vincta.
Herbivore Preference and Algal Palatability Across a Vertical Intertidal Gradient PI's: Carol Thornber and Jay Stachowicz Variation in grazing intensity can play important roles in setting the composition and diversity of producer assemblages. However, despite strong gradients in the composition and abundance of herbivores across vertical intertidal gradients, we know little about how macroalgal palatability and associated herbivore defenses vary across these intertidal zones. As herbivore pressure decreases with increasing tidal elevation, plant defense theory predicts that seaweeds should be more palatable and less defended than their lower intertidal counterparts. Therefore, to determine whether this pattern existed across a vertical gradient in the rocky intertidal of Northern CA, we examined the relative palatability of nine pairs of closely related macroalgal species that occupy different tidal elevations, to three of the most common local herbivores (Thornber et al. 2008).