
Gerardo AvalosUniversity of Costa Rica | UCR · Escuela de Biología
Gerardo Avalos
PHD Plant Physiological Ecology / Tropical Ecology
Allometry and carbon sequestration in palms. Hummingbird ecology and pollination networks.
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90
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Introduction
Physiological adaptations of tropical plants to spatio-temporal changes in the availability of light. Physiological ecology of lianas. Biomechanics of tropical palms. Palm allometry and carbon sequestration. Functional ecology and aerodynamics of hummingbirds. Tropical ecology and conservation. Multivariate statistics. I am a full professor of ecology at the University of Costa Rica and the director of the Center for Ecological Resilience Studies at The School for Field Studies.
Additional affiliations
September 2001 - present
January 1991 - present
January 2005 - December 2012
Publications
Publications (90)
High-altitude mountain bogs, located in the Central and Talamanca Mountain Ranges of Costa Rica (1200–3100 m a.s.l.), remain one of the least explored inland aquatic ecosystems and potentially one of the most geographically restricted. These unique wetlands are confined to topographic depressions with limited drainage, rely solely on rainfall for t...
Analysis of the patterns of distribution, diversity, uses, and conservation status of the palm flora of Costa Rica.
Bird nests play a fundamental role in reproductive success, as the structure, size, and composition of nest materials influence factors like thermal insulation, protection from predators and parasites, exposure to toxins, structural stability for egg-laying and chick-rearing, and fledgling release. Nests represent an extension of the bird's phenoty...
Resumen El objetivo de este artículo es dar a conocer el proyecto de acción social EC-614 de la Universidad de Costa Rica "Árboles de la paz sobrevivientes a la bomba atómica de Hiroshima: Fase 1: establecimiento de las plántulas en Costa Rica", así como el impacto que ha tenido especialmente en bibliotecas públicas y como aporte al cumplimiento de...
Analizamos la distribución espacial y temporal de la incidencia del fuego en el ecosistema de sabanas húmedas del sur de Costa Rica para el periodo 2001 al 2022 usando datos MODIS. Si bien el área bajo investigación cuenta con referencias históricas de la afectación del fuego, no se había realizado hasta el momento un análisis sobre la cronología y...
The cover image is based on the paper "A phylogenetic perspective on ecological specialisation reveals hummingbird and insect pollinators have generalist diets" by Maglianesi et al. (2024), https://doi.org/10.1111/oik.10208.
A male of the Talamanca Hummingbird gives a touch of colour to the oak forests near the páramo in the Costa Rican highlands....
Specialisation in food resource use is a crucial process that fosters species coexistence in plant–animal networks, contributing to the maintenance of biodiversity, ecological complexity, and community stability. Notably, although there is a vast literature on ecological specialisation in pollination systems, the evolutionary similarity among the p...
Functional traits are morphological and physiological characteristics that determine growth, reproduction, and survival strategies. The leaf economics spectrum proposes two opposing life history strategies: species with an "acquisitive" strategy grow fast and exploit high-resource environments, while species with a "conservative" strategy emphasize...
We analyzed the relationship between whole-plant carbon sequestration and specific leaf area (SLA) in six palm species from the Caribbean slope of Costa Rica. SLA is a fundamental functional trait associated with the whole-plant biomass allocation strategy, so it should serve as a proxy for estimating the carbon sequestration of the entire individu...
Section
Key message
Specific leaf area (SLA, cm2g− 1) is a fundamental leaf economics spectrum trait, which predicted the total carbon sequestered at the individual level in understory palms of Socratea exorrhiza.
AbstractSection
Abstract
Evaluating intraspecific and ontogenetic variation in SLA is critical to understand how functional traits influ...
Hummingbirds play a crucial role in pollination networks, as their visit to floral resources can determine plant reproductive success. We investigated how differences in bill length of hummingbirds, within and between species, affect the range of use of floral resources. Species with short bills will be mainly restrictedto visiting plants with shor...
With more than 2,600 species and 181 genera, palms (Arecaceae) are one of the
most diverse and widely distributed plant families in tropical environments (Baker and Dransfield, 2016). Although they make up a modest portion of the above-ground biomass in most neotropical forests (DeWalt and Chave, 2004), their contribution increases in places where...
Functional traits are morphological and physiological characteristics that determine growth, reproduction, and survival strategies. The leaf economics spectrum proposes two opposing life history strategies: species with an "acquisitive" strategy grow fast and exploit high-resource environments, while species with a "conservative" strategy emphasize...
According to Rensch’s rule, in species where males are the larger sex, increasing body size is coupled with increased sexual size dimorphism (SSD), whereas in species where females are larger, SSD decreases with body size. We describe the variation in SSD for body mass and its fit to Rensch´s rule in 45 species of Costa Rican hummingbirds. We exami...
We present allometric models for estimating total carbon content and above ground carbon (AGC) for the Arecaceae family, and for seven abundant neotropical palm species: the canopy species Socratea exorrhiza (n = 10) and Iriartea deltoidea (n = 10), the sub-canopy palm Euterpe precatoria (n = 10), and the understory species Asterogyne martiana (n =...
Plant-animal interactions may be associated with mutualistic relationships shaped by coevolution. Hummingbird relationships with plants can be complex, resulting in strategies of varying degrees of specialization. We analyzed the pollination network of the hummingbird and plant ensemble of Cerro de la Muerte, Talamanca, Costa Rica, according to the...
Central American biota has been shaped by natural biological exchanges resulting from complex geological and climatic events during its formation. However, it has also been significantly affected by the arrival and spread of humans, which introduced domesticated species as well as others that incidentally came with them. Several non-native plant sp...
We present allometric models to estimate total carbon content and above ground carbon (AGC) for the family Arecaceae, and for 7 abundant neotropical palm species (the canopy species Socratea exorrhiza and Iriartea deltoidea , the sub-canopy palm Euterpe precatoria , and the understory species Asterogyne martiana , Prestoea decurrens , Geonoma inter...
Gerardo Avalos, Olivia Sylvester, Milena Cambronero, Alí García-Segura
Abstract. Costa Rica has one of the highest species concentrations in the world. The estimated number of species of all organisms is 500,000, which represents 5% of the world's biodiversity. This country has 111 palm species (approximately 4.26% of the world's total), of which...
Costa Rica is one of the most diverse countries in the Neotropics. It has the highest species concentration per unit area of terrestrial ecosystems. The country has a vascular flora of approximately 10 712 species, of which 1048 (9.7%) are introduced, and of these, 47 (0.4%) are considered invasive. Invasive plants are linked to species extinctions...
Resumen El ecosistema de sabana ocupa una importante superficie a nivel mundial con alrededor de 15 millones de km 2 , 43% del área continental. En Costa Rica, la mayor extensión de sabana se encuentra en la cuenca del Río General en el sur del país. En este artículo analizamos el contexto biofísico, la historia paleoecológica y paleoclimática, el...
El artículo presenta el código de ética para la observación de aves en Costa Rica propuesto por la Asociación Ornitológica de Costa Rica
Documenting changes in species distribution is critical to understanding bird diversity, establishing a baseline for comparative studies, quantifying bird turnover rates, and identifying groups sensitive to anthropogenic disturbances. We examined changes in diversity of the avifauna of Carara National Park (Costa Rica), a transitional forest border...
El uso de comederos artificiales para alimentar a las aves es una práctica extendida y de uso generalizado principalmente en sitios turísticos, tales como hoteles de montaña, parques naturales, y jardines privados. En el caso de sitios turísticos y parques naturales la principal motivación para establecer comederos es atraer más visitantes. Los com...
Tropical palms reach tree-like heights without a vascular cambium through sustained cell expansion and lignification of primary tissues, but only a fraction of palms have been explored in their allometric relationships. Here, our main question was to determine how palms depart from the traditional mechanical models developed for trees and how they...
Páramos are high mountain tropical ecosystems characterized by being dominated by herbaceous plants and small shrubs. Physiognomically, they are similar to the alpine tundra. These ecosystems are of great importance due to their high degree of endemism and their high vulnerability to climate change. Few studies have analyzed the seasonal variation...
Shade tolerance (the capacity to survive and grow over long periods under shade) is a key component of plant fitness and the foundation of current theories of forest succession in tropical rain forests. It serves as a paradigm to understand the optimal allocation of limited resources under dynamic light regimes. I analyze how tropical rain forest s...
I report the latest assessment of species richness for the most conspicuous groups of organisms in Costa Rica, highlighting the key terrestrial ecosystems on which they depend, as well as to sketch the most important ecological patterns responsible for generating and maintaining this unique biodiversity. I end this chapter by identifying the curren...
Abstract. Documenting changes in species distribution is critical to understanding bird diversity, establishing a baseline for comparative studies, quantifying bird turnover rates, and identifying sensitive groups to anthropogenic disturbances. We examine changes in diversity of the avifauna of Carara National Park (Costa Rica), a transitional fore...
SUMMARY. We examined how artificial feeders affected pollen loads and competitive interactions in the hummingbirds of Cerro de La Muerte (3,100 masl, 4 species) and Monteverde (1,300 masl, 12 species, 4 sites: Selvatura, Monteverde Cloud Forest Reserve -MVCFR-, the Hummingbird Gallery and San Luis Biological Reserve) in Costa Rica. All the study si...
The functional composition of plant communities in montane regions has been studied for decades, and most recent analyses find that environmentally favourable landscapes at lower altitudes tend to be dominated by species with resource-acquisitive traits, while more resource-conservative taxa dominate higher-altitude communities. However, it is uncl...
Palms are highly abundant in tropical forests, representing one of the most relevant groups of angiosperms in various ecological roles and with numerous cultural and economic uses. However, most carbon inventories have focused on dicotyledonous trees and have consistently neglected palms. We describe patterns of carbon fraction in 86 palms of 7 spe...
Palms are important structural components of tropical rain forests. Nonetheless, information on their propagation potential under nursery conditions to facilitate their use in forest restoration is scarce. This article studies the propagation potential of a tropical palm assemblage focusing on seed collection and germination patterns in the rainfor...
Altered landscapes play a major role in biodiversity conservation and carbon (C) storage in the tropics. There is increasing evidence that C storage potential is controlled by tree functional diversity, but underlying mechanisms are debated. We analyzed the effects of trait dominance (mass-ratio hypothesis), species diversity, and trait variation (...
ABSTRACT. Stem growth of the neotropical palm Euterpe precatoria (Arecaceae) in an agroforestry system under sun and shade conditions was compared for 3.25 years on the Caribbean slope of Costa Rica. Euterpe precatoria is illegally extracted for its palm heart across its latitudinal range. As a solitary species, heart of palm extraction results in...
Peccaries and palms maintain complex interactions centered in the consumption of plant biomass in relationships ranging from seed dispersal to herbivory. At La Selva Biological Station, Costa Rica, we have observed collared peccaries (Pecari tajacu) chewing the young roots of the stilt root cones of the palm Socratea exorrhiza, which modifies the s...
Roads immersed in conservation areas will increase in number, size, and traffic over the next decade, and thus, understanding their effects on forest-dependent wildlife is crucial for improving current management practices and reducing the negative impacts of roads on sensitive species. We examined the influence of route 32 (a.k.a. Guápiles Highway...
Successful forest restoration in tropical environments is limited by the paucity of studies on the initial establishment and early survival requirements of seedlings of most native tropical tree species under disturbed conditions. Here, we evaluated the initial growth responses and the regeneration potential of seedlings of five tree species native...
Light is critical for plant establishment, growth, and survival in wet tropical forests. The objective of this chapter is to analyze paradigms of photosynthetic performance and life history traits of tropical forest trees to contrasting light environments across the forest floor, gaps and upper canopy. Physiological and morphological plasticity
as...
The amount of new biomass produced in an ecosystem per unit of time is termed primary production. The study of the factors that shape primary production is central to understanding key ecosystem processes, such as the ecological consequences of increased temperature and CO2 concentration on primary production itself, the interface between the trans...
Understanding the linkage between biological diversity and ecosystem function is critical for managing tropical landscapes in the face of environmental change, although the mechanisms behind these relationships remain debated. We studied tree diversity and carbon storage in 14 shade-grown coffee farms and 6 forest fragments in Costa Rica. At each s...
Premise of the study: Few studies have analyzed the physiological performance of different life stages and the expression of ontogenetic niche shifts in lianas. Here, we analyzed the photosynthetic and morphological acclimation of seedlings of Stigmaphyllon lindenianum ,Combretum fruticosum , and Bonamia trichantha to distinctive light conditions i...
Some understory insectivorous birds manage to persist in tropical forest fragments despite significant habitat loss and forest fragmentation. Their persistence has been related to arthropod biomass. In addition, forest structure has been used as a proxy to estimate prey availability for understory birds and for calculating prey abundance. We used a...
Some understory insectivorous birds manage to persist in tropical forest fragments despite significant habitat loss and forest fragmentation. Their persistence has been related to arthropod biomass. In addition, forest structure has been used as a proxy to estimate prey availability for understory birds and for calculating prey abundance. We used a...
The neotropical liana Gnetum leyboldii (Gnetaceae) is a gymnosperm that resembles angiosperms in wood anatomy, overall morphology, and seed dispersal mechanism. Like other woody lianas, seedlings germinate in the shaded forest understory and start climbing towards the canopy, being exposed to sites with extreme differences in light conditions. Howe...
The neotropical liana Gnetum leyboldii (Gnetaceae) is a gymnosperm that resembles angiosperms in wood anatomy, overall morphology, and seed dispersal mechanism. Like other woody lianas, seedlings germinate in the shaded forest understory and start climbing towards the canopy, being exposed to sites with extreme differences in light conditions. Howe...
Knowledge on the growth responses of understory palms to changing light conditions within neotropical cloud forests is limited. The low light regime of these environments, in addition to persistent cloudiness, low ambient temperatures, and slow nutrient cycles, imposes significant constraints on biomass accumulation. Here, we evaluate how changes i...
The neotropical palm Euterpeprecatoria is subject to extraction for its valuable palm heart. The development of management and conservation practices for this species requires understanding of its population structure, dynamics, and traditional use across the range of environments it inhabits, from different successional stages in continuous forest...
Influencia de la etapa de sucesión, fragmentación y exposición a la extracción en la estructura poblacional de Euterpe precatoria (Arecaeae). The neotropical palm Euterpe precatoria is subject to extraction for its valuable palm heart. The development of management and conservation practices for this species requires understanding of its population...
Hummingbirds are the most specialized flying vertebrates, having the capacity to hover, which is the most energetically expensive flight type. Hummingbirds show great divergence in body construction, affecting flight performance and position along the dominance hierarchy. Given strong selective pressures on hummingbird morphological variation and p...
Most research on bioluminescent fungi is concentrated on their taxonomic relationships, while the basics of their natural history and ecological relationships are poorly understood. In this study, we compared the distribution of bioluminescent fungi between old-growth and secondary forest as related to four different soil types at the tropical rain...
Most research on bioluminescent fungi is concentrated on their taxonomic relationships, while the basics of their natural history and ecological relationships are poorly understood. In this study, we compared the distribution of bioluminescent fungi between old-growth and secondary forest as related to four different soil types at the tropical rain...
• Premise of the study: Environmental heterogeneity is a strong selective force shaping adaptation and population dynamics across temporal and spatial scales. Natural and anthropogenic gradients influence the variation of environmental and biotic factors, which determine population demography and dynamics. Successional gradients are expected to inf...
Although sugar-water feeders are commonly used by enthusiasts to attract hummingbirds, little is known about how they affect hummingbird behavior and flower use. We studied the highland hummingbird assemblage of Cerro de La Muerte, Costa Rica, both at a site with permanent feeders (La Georgina Restaurant) and further from it. We examined how feeder...
To support the implementation of policies that recognize human uses of wild
plants, we documented palm ethnobotany within or bordering eight protected
areas in Costa Rica. Through participant observation and semi-structured
interviews with 37 participants from 18 communities, we documented the
cultivation and harvest of 32 palm species from 21 gene...
We document the capacity of the neotropical palm Euterpe precatoria var longevaginata for vegetative propagation by measuring the number and size of ramets attached to mother palms and associating ramet frequency with the size of mother palms. Euterpe precatoria is subjected to intensive extraction for its edible palm-heart. Being single-stemmed, e...
The neotropical terrestrial insectivore Henicorhina leucosticta (Troglodytidae) maintains long-term territories through vocalizations and forages among leaf litter trapped in the understorey vegetation and ground litter. The relationship between forest structure and H. leucosticta territory size was studied in La Selva Biological Station, Costa Ric...
We estimated the magnitude of the total leaf area of the neotropical palm Euterpe oleracea and examined its allometry relative to the variation in stem height and diameter at La Selva Biological Station in Costa
Rica. The allometric relationships between frond leaf area and frond length (from tip to base), and between frond leaf area
and number of...
The lack of secondary meristems shapes allometric relationships of the palms, influencing species segregation according to their capacity to adjust form and function to spatial and temporal changes in environmental conditions. We examined the stem height vs. diameter allometry of Euterpe precatoria across environmental gradients and measured how te...
Illegal Palm Heart (Geonoma edulis) Harvest in Costa Rican National Parks: Patterns of Consumption and Extraction. Illegal extraction of non-timber forest products in the tropics is widespread, and many protected areas face the challenge
of balancing conservation needs with cultural practices related to the use and extraction of animals and plants....
Illegal extraction of non-timber forest products in the tropics is widespread and many protected areas face the challenge of balancing conservation needs with cultural practices related to the use and extraction of animals and plants. We studied the illegal wild palm heart extraction of Geonoma edulis, locally known as súrtuba, in Volcán Poás and B...
In tropical dry forests most plants are deciduous during the dry season and flush leaves with the onset of the rains. In Costa Rica, the only species displaying the opposite pattern is Bonellia nervosa. To determine if seasonal changes in light availability are associated with the leaf and reproductive phenology of this species, we monitored leaf p...
En Costa Rica, el estudio de los ecosistemas de altura, y en especial el ecosistema de páramo, ha sido históricamente relegado por biólogos y naturalistas, en comparación con ecosistemas más diversos, menos hostiles, y de relativamente mejor acceso, como los bosques tropicales de bajura, algunos de los cuales cuentan ahora con excelente alojamiento...
Lianas impose intense resource competition for light in the upper forest canopy by displaying dense foliage on top of tree crowns. Using repeated access with a construction crane, we studied the patterns of canopy colonization of the lianas Combretum fruticosum and Bonamia trichantha in a Neotropical dry forest in Panama. Combretum fruticosum flush...
Rica.—Euterpe precatoria Mart. (Arecaceae) experiences intensive illegal extraction for its edi-ble meristem in Costa Rica. This solitary palm, which may reach a height of 25 meters (m), is common in low-and mid-elevational neotropical forests from sea level to 1,150 m of elevation from Belize to Bolivia (1). The extraction of the heart of palm res...
The tropical rain forest understory palm, Calyptrogyne ghiesbreghtiana Linden ex H. Wendl. (Arecaceae), exploits
forest microhabitats characterized by dense shade conditions. In plants exploiting light-limited environments natural selection
has shaped the architecture and pattern of leaf display to increase the efficiency of light interception. The...
Palms represent one of the most conspicuous groups of Angiosperms in Tropical Forests. Although their contribution to overall species diversity is small, they influence forest structure and dynamics, and play an essential role in foodwebs. The distribution of palms reflects fine shifts in environmental heterogeneity and light availability. In arbor...
In the dry forest of Santa Rosa National Park, Costa Rica, the understory shrub Jacquinia nervosa presents an inverse pattern of phenology that concentrates vegetative growth and reproduction during the dry season. In this study, we tested the "escape from herbivory" hypothesis as a potential explanation for the inverse phenological pattern of J. n...
Habitat fragmentation, along with other human-induced disturbances, increase the vulnerability of native habitats to be invaded by aggressive, ecologically released, exotic species. Syzigium jambos (L.) Alston (Myrtaceae, Rose Apple) is an important invader still spreading throughout Hawaii, the Antilles, Central and South America. This study exami...
yMany arborescent palms develop a stilt root cone that provides increased mechanical support on steep hillsides, better root aeration under waterlogged conditions, resprouting after mechanical damage, and rapid stem elongation. However, for most species the role of stilt roots is not well understood. We determined how palm size and slope inclinatio...
Band-Tailed Pigeons (Columba fasciata) range from Vancouver Island and southwestern British Columbia (Canada), through the mountainous west of the United States, to Mexico, Central America, northern and west-ern South America, and western Argentina (Skutch 1964, 1983). Although, in the north-ernmost portion of its range, Band-Tailed Pigeons are fou...
We explored the short-term adjustment in photochemical efficiency (Fv/Fm) in adult and young leaves of the understory neotropical shrub Psychotria limonensis Krause (Rubiaceae) in response to rapid changes in the light environment. Leaves were collected from 20 individual plants growing under sun and shade conditions on Gigante Peninsula, Barro Col...
Arborescent palms are abundant canopy components of tropical lowland and montane forests up to 1000–1500 m (Kahn & de Castro, 1985, Peres 1994, Kessler 2000). Their distribution reflects fine environmental gradients that affect the diversity of tropical plants. These gradients are the result of differences in successional status, soil type and nutr...
Tropical plant canopies show abrupt changes in light conditions across small differences in spatial and temporal scales.
Given the canopy light heterogeneity, plants in this stratum should express a high degree of plasticity, both in space (allocation
to plant modules as a function of opportunity for resource access) and time (photosynthetic adjust...
Questions
Questions (22)
I am researching the genus Bonellia and would like better to understand the mechanisms of seed dispersal and pollination in its species. Could anyone explain or provide references or contacts on how pollination and dispersion occur across the different species within this genus? I appreciate your time.
Allometric equation estimate carbon and above-ground biomass based on diameter, height, tissue density, etc.
I have a published phylogenetic tree but no access to the rough data used to generate the tree. I want to compare among clades in terms of morphological characters. How do I include the phylogenetic correction? Should I just measure the distance between clades and use this as my phylogenetic correction? The phytools package in R assumes I have the rough tree data, and I don´t. Some suggestions will be most welcomed.
I have had some success germinating Ginkgo seeds in Costa Rica. I would like to know recommendations to secure seedling establishment. Right now they are in 1.5 L plastic bags on organic soil at field capacity. Do they need a fertilization supplement? What could be the best tips to share to secure seedling growth and establishment? How long could they take to reach a size amenable for transplantation into the field?
Dear all, I have a limited supply of Ginkgo biloba seeds from Japan. My purpose is to germinate the seeds and hopefully establish some G. biloba specimens in Costa Rica. What could be the best treatment to trigger germination and subsequently favor the seedling establishment and survival? I have access to these elevations for this purpose: 600, 1200, and 2300 masl. I have been told that the highlands (> 2000 masl) might be best. If you know a few tricks of the trade that you could share, that will save me a lot of time and effort, and some seeds too. The tropics could be challenging for temperate gymnosperms.