Bocas del Toro Isla Popa by Carrie Sims


Project: Species coexistence, commonness, and rarity in high-diversity ecosystems

Project title

Species coexistence, commonness, and rarity in high-diversity ecosystems

Photo credit to Carrie Sims

Mentor name

Sean Connolly (


Naos Marine Laboratories

Project summary and objectives

This project uses mathematical and statistical modelling, alongside empirical approaches, to understand how species coexist in highly species-rich communities such as coral reefs and rainforests, how spatial and temporal patterns in the relative abundances of species in such communities are maintained, and on the consequences of interactions between species for the provision of key ecosystem functions. Within this overall framework, the specific focus on an intern’s work is somewhat flexible. Work may include any of the following types of approaches. (1) The theoretical analysis of mathematical models of community dynamics to determine how particular types of species interactions influence species coexistence, relative abundance, and aggregate community properties such as biomass production. (2) The fitting of process-based community dynamics models to ecological data, to infer the roles of species interactions and species’ responses to environmental fluctuations in structuring species-rich communities. (3) The analysis of phenomenological statistical models to spatial and temporal biodiversity data, to identify and explain macroecological patterns in biodiversity. (4) The construction and analysis of biodiversity simulation models, to understand how different types of complexity in community structure and dynamics influences the production of biodiversity patterns. (5) The design and implementation of experiments or analyses of experimental data on coral demographic parameters, particularly those relevant to ecological interactions at life cycle stages that are significant bottlenecks (for example, competition between recently-settled coral larvae).
For approaches 1-2 above, applicants should have a solid foundation in mathematics, and for approaches 3-4, in statistics, in addition to some familiarity with biology.

Mentorship goals

The intern will become familiar with biodiversity theory, and with the application of cutting-edge quantitative approaches to the study of biodiversity, working closely with the Primary Advisor, staff scientist Sean Connolly and other Fellows associated with this project.

Intern’s role, desired background time commitment (appointment period is 3 months) and expected products

The intern will work ~40 hours per week. If experiments are taking place, working days and hours will vary dependent on the needs of the project. The final product could include a poster presentation or project report, if required (e.g., for course credit at a home institution), and ideally would yield results that could be published in a peer-reviewed journal, with the intern as a co-author or potentially lead author.

What are the regularly held occasions for group discussions, attendance at lectures, career counseling, and other educational and experiential opportunities for your interns?

Advising/mentoring meetings with mentors would occur at least weekly, on average. Additional advice and support would be available from lab members in both one-on-one and lab meetings. Additionally, the intern would be encouraged to attend regular lab meetings, as well as STRI research seminars, including weekly Tupper seminars and approximately fortnightly informal science seminars at Naos Marine Laboratory, where they will have the opportunity to interact with members of the STRI community involved in other projects.

List of suggested readings

Álvarez-Noriega, M.; J.S. Madin, A.H. Baird, M. Dornelas, and S. R. Connolly. 2023. Disturbance-induced changes in size-structure promote coral biodiversity. American Naturalist 202:

Tsai, C-H., H.P.A. Sweatman, L.M. Thibaut, and S.R. Connolly. 2022. Volatility in coral cover erodes niche structure, but not diversity, in reef fish assemblages. Science Advances 8: eabm6858.

Sims, C. A., E. M. Sampayo, M. M. Mayfield, T. L. Staples, S. J. Dalton, N. Gutierrez-Isaza, and J. M. Pandolfi. 2021. “Janzen–Connell Effects Partially Supported in Reef-Building Corals: Adult Presence Interacts with Settler Density to Limit Establishment.” Oikos 130: 1310–25.

Sampayo, E.M., Roff, G., Sims, C.A. et al. Patch size drives settlement success and spatial distribution of coral larvae under space limitation. Coral Reefs 39, 387–396 (2020).

Connolly, S.R., S.A. Keith, R.K. Colwell, and C. Rahbek. 2017. Process, mechanism, and modelling in macroecology. Trends in Ecology and Evolution 32: 835-844.

Connolly, S.R., T.P. Hughes, and D.R. Bellwood. 2017. A unified model explains commonness and rarity on coral reefs. Ecology Letters 20: 477-486.

Back to Top