Faculty and Staff

Gerardo Avalos, PhD

Gerardo Avalos, PhD

Center Director
Costa Rica
B.S. in Biology
University of Costa Rica
M.S. in Tropical Ecology and Conservation
University of Missouri-St. Louis (MO, USA)
Ph.D. in Tropical Ecology and Conservation (Ecophysiology)
University of Missouri-St. Louis (MO, USA)
SFS 4910/4920 Directed Research
The School for Field Studies
SFS 2050 Language, Culture and Society of Costa Rica
The School for Field Studies
Multivariate Statistics, Natural History of Costa Rica, Ecology of Palms
Associate Professor (University of Costa Rica)
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Faculty Profile

Gerardo Avalos holds a Ph.D. and an M.S. in plant physiological ecology and conservation from the University of Missouri at St. Louis. After obtaining his B.Sc. in Biology at the University of Costa Rica, Gerardo began his graduate studies at the University of Colorado at Boulder, and then he transferred to the University of Missouri – St. Louis, where he investigated the physiological ecology of lianas using a construction crane to reach the canopy working as a fellow from the Smithsonian Tropical Research Institute in Panama. His dissertation examined the light acclimation of tropical lianas to temporal and spatial changes in light availability at the surface the forest canopy. His current research interests include the biomechanics of tropical palms, the carbon sequestration and functional trait ecology of palms, invasive plant ecology, and the functional ecology of hummingbirds including network dynamics across three trophic levels. After serving for 6 years as the Center for Sustainable Development Studies resident ecologist, Gerardo became the Center Director in 2007. He is a Full Professor at the University of Costa Rica where he teaches Botany, Ecology, Natural History, and Multivariate Statistics.

Areas of Expertise

  • Carbon sequestration
  • Functional ecology of hummingbirds
  • Multivariate statistics
  • Palm allometry
  • Physiological ecology of tropical plants
  • Plant biomechanics
  • Tropical ecology and conservation
Academics & Research

Research Interests

I am interested in the physiological adaptations of tropical plants to spatial and temporal changes in the availability of light, especially the characters that are responsible for the expression of plasticity at the extremes of the light gradient in a tropical forest: the understory and the canopy. My research have covered different groups, including birds, insects, and plants, and currently include the biomechanics of tropical palms, functional trait ecology, carbon sequestration, and the ecological morphology of hummingbirds especially sexual size dimorphism.

Professional Activities

Member, Association for Tropical Biology and Conservation (ATBC)

Member, Society for Economic Botany

Member, Botanical Societry of America

Member, Editorial Board of Oecologia (Ecophysiology section)

Coordinator Scientific Committee of the Ornithological Association of Costa Rica

Editor of Zeledonia, the journal of the Ornithological Association of Costa Rica

International Palm Society (IPS)

Red Latinoamericana de Ecofisiólogos Vegetales (REDLEV)

Research Projects

Phoresis relationships of flower mites (Acari: Melicharidae) and hummingbirds (Aves: Trochilidae) in a cloud forest

This project examines the symbiotic relationships between plants, hummingbirds, and mites in a tropical cloud forest. By capturing hummingbirds, collecting pollen and mites from hummingbird plumage, and using action cameras to record flower visitation, we are mapping the web of interaction across three trophic levels (pollinators, plants, and nectar-eating mites). Mites use hummingbirds to colonize flowers and disperse in a relationship called phoresis. The project seeks to unravel the trophic complexity of this assemblage in one of the most diverse environments in the Neotropics, such as the tropical cloud forest. This project is carried out in collaboration with the Center for Research in Microscopic Structures (CIEMIC) of the University of Costa Rica.

Palm Allometry and Carbon Sequestration

I have been working on palm ecology for a long time. I explored the population growth and illegal extraction dynamics of Euterpe precatoria, the allometric relationships of over 7 species of tropical palms, and more recently the generate allometric equations based on key morphological characters to understand how the capacity for carbon sequestration varies among palm species from different strata. I have applied these equations to estimate the amount of carbon that palms contribute to tropical forests with the aim of improving our estimations of carbon sequestration in tropical habitats. More recently, I am exploring the functional ecology of critical traits such as specific leaf weight to estimate the carbon sequestration of an entire individual palm.

Ecological Morphology of Hummingbirds

I fell in love with hummingbirds since my undergraduate years. I have explored the dynamics of pollination in the highlands and mid-elevations of Costa Rica looking at how the morphology of hummingbirds affect their plan use and how this usage differs among species and sex within a species. More recently, I have examined the evolution of sexual-size dimorphism in hummingbirds. Our current project is looking at tri-trophic level interactions in a pollination network in cloud forests.

Trees of Peace of Hiroshima

This is a project that I am developing in collaboration with the Hiroshima Green Legacy Foundation, the Hiroshima Botanical Garden, the Lankester Botanical Gardens in Costa Rica, the University of Costa Rica, and SFS, to establish the descendant of trees that survived the atomic bombing of Hiroshima in public places in Costa Rica to serve as symbols of peace. Under the current conditions of global warming, war, corruption, greed, and inequality, it is urgent to create a message of resilience to show that humanity, like the trees that survived Hiroshima, can rise again, and create a culture of social justice and peace. Right now, I have several seedlings of the ancient tree Ginkgo biloba and I have used them to give talks on the need to build a culture of peace. Read here

Research Gate

Visit Dr. Avalos’ Research Gate profile to view select publications.



Report of bird captures in the páramo of Cerro Buena Vista, Costa Rica.

Salguero-Hernández, G. & G. Avalos. (2019). Report of bird captures in the páramo of Cerro Buena Vista, Costa Rica. Zeledonia 23(1): 55-59.

Biological invasions by plants in continental Central America.

Chacón-Madrigal, E., Avalos, G., Hofhansl, F., Coronado, I., Ferrufino, L., MacVean, A. & D. Rodríguez. (2019). Biological invasions by plants in continental Central America. Chapter 9 in: Global Plant Invasions, Springer Verlag.

Functional Ecology and Conservation of Palms.

Avalos, G., Emilio, T., Andersen, K. M., & Alvarez-Clare, S. 2022. Frontiers in Forests and Global Change, 5:1021784. doi: 10.3389/ffgc.2022.1021784.

Allometric models to estimate carbon content in Arecaceae based on seven species of neotropical palms.

Avalos, G., Cambronero, M. & Vergnani, C. 2022. Frontiers in Forests and Global Change 5: doi: 10.3389/ffgc.2022.867912

Biodiversity of Costa Rica, numbers, processes, patterns, and challenges.

Avalos, G. 2019. Still searching the rich coast: Chapter 4 in Pullaiah, T. (editor). Global Biodiversity Volume 4: Americas. CRC Press, Florida, USA.

Biological invasions by plants in continental Central America in Clements

Chacón-Madrigal E., Avalos G., Hofhansl F., Coronado I., Ferrufino-Acosta L., MacVean A., and Rodriguez D. 2021. D.R., Joshi, S., Upadhyaya, M.K. and Shrestha, A. Global Plant Invasions, London: Springer Nature.

Invasive plants of Costa Rica: current-status and research opportunities.

Avalos, G., E. Chacón-Madrigal, & L.G. Artavia. 2021. Chapter 5 in: Volume 5. American and Caribbean Invasions. John Wiley & Sons.

Scaling of stem diameter and height allometry in 14 neotropical palm species of different forest strata.

Avalos, G., Gei, M., Ríos, L.D., Otárola, M.F., Cambronero, M., Alvarez-Vergnani, C., Sylvester, O. and Rojas, G., 2019. Oecologia 190(4):757-767. https://doi.org/10.1007/s00442-019-04452-7

Patrones de diversidad, distribución, usos etnobotánicos, y conservación de las palmas de Costa Rica.

Avalos, G., O. Sylvester, M. Cambronero-Quesada, & A. García-Segura. 2022. In: Pulido-Silva, M.T. & N.L. Sander. Usos de Palmas en Latinoamérica.

Allometric models to estimate carbon content in Arecaceae based on seven species of neotropical palms.
Avalos, G., Cambronero, M., & Alvarez-Vergnani, C. (2022).

Grants and Awards

Keynote speaker to the International Palm Society meeting in San Jose, Costa Rica, May 2008.


High phylogenetic but low functional turnover of Melastomes along a tropical elevational gradient.

Kandlikar, G., Carita-Vaz, M., Kriebel, R. Vargas, G., Michelangeli, F. Cordero, R., Almeda, F., Avalos, G., Fetcher, N., & Kraft N. J. B. 2015. 100TH Annual Meeting of the Ecological Society of America, Baltimore, Maryland.

The effect of management and plant diversity on carbon storage in coffee agroforestry systems in Costa Rica. Functional diversity: linking conservation and climate change mitigation in tropical altered landscapes.

Hager, A. & G. Avalos. 2015. Conference: 21st Annual Conference, International Society of Tropical Foresters – Conserving biodiversity across multiple use landscapes through strategic governance and land-use planning, Yale School of Forestry and Environmental Studies, New Haven, Connecticut.

Influence of Aerodynamics On the Dominance Hierarchy of a Hummingbird Assemblage in Costa Rica.

Avalos, G., G. Lee & A. Soto. 2013. Proceedings of the Association for Tropical Biology and Conservation, San José, Costa Rica, June 2013.

Aerodynamic and morphological variation in the highland hummingbirds of Cerro de La Muerte, Costa Rica.

Avalos, G. and G. Lee. 2012. III Congress of Ornithology, Costa Rica. San José.

Morphology and Growth of a Harvested Cloud Forest Understory Palm in Relation to its Local Light Environment.

Sylvester, O. and G. Avalos. 2009. Meeting of the Latinamerican Network of Botany, San Jose, Costa Rica, November 2009.

Participation in the Symposium on Protected Areas

San Ramon, Costa Rica, July 2008.

Keynote speaker to the International Palm Society meeting in San Jose, Costa Rica

May 2008. The conference versed on the Functional Ecology of Palms in Costa Rica.

Participation Symposium Functional Ecology of tropical trees

In the annual reunion of the Association for Tropical Ecology and Conservation in Michoacán, Mexico, July 2007.

Participation in the workshop of The Inter-American Biodiversity Information Network (IABIN)

In NBIO, Costa Rica November 20-22, 2006.

Plasticity and allometry in the Stilt root structure in 8 woody palms across successional stages and soil types at La Selva Biological Station, Costa Rica.

M.G. Gei and G. Avalos. 2006. IX latinamerican Interntional Symposium of Botany, Santo Domingo, Domenic Republic, May 2006.

Impact of illegal extraction of palm Euterpe precatoria.

Avalos, G. & M. Mauricio Fernandez. 2005. Congress of Conservation and Wildlife Management, 21 to 25 February 2005, Universidad Nacional, Heredia, Costa Rica.

Impact of highway 32 on the bird community of the Braulio Carrillo National Park.

Avalos, G. & E. Bermúdez. 2005. Congress of Conservation and Wildlife Management, 21 to 25 February 2005, Universidad Nacional, Heredia, Costa Rica.

Spatial and temporal changes in the distribution and diversity of aquatic insects in the Braulio Carrillo National Park

Avalos, G. 2003. IV Congreso Nacional de Biología Clodomiro Picado, San José Costa Rica.

Fragmentation Effects of a Major Highway on Bird Distribution in Braulio Carrillo National Park, Costa Rica.

Avalos, G., A. Soto, J. Veenstra, T. Smith and C. Keller. 2002. Proceedings of the Association for Tropical Biology, Panama city, Panama, June 2002.

Effect of medium and light availability on photosynthetic acclimation of tropical lianas.

Avalos, G. 1998. VII Congreso Latinoamericano de Botanica: Diversity and Conservation of plant resources in Latin America. Mexico DF, Mexico, in October 1998.

Impact of seasonal changes in light availability on the physiological adaptation of tropical lianas.

Avalos, G. & S.S. Mulkey. 1997. Tropical Diversity: Origins, maintenance and conservation. Symposium and Annual Meeting. Association for Tropical Biology and OTS, Costa Rica San Jose June 1997.