Bryophyte and lichen biomass and nitrogen fixation in a high elevation cloud forest in Cerro de La Muerte, Costa Rica

Cloud forests have been found to lose more nitrogen in stream discharge than they gain from atmospheric deposition. They also support a large diversity and biomass of tree epiphytes, predominately composed of cryptogams. Since cryptogam epiphytes harbor nitrogen fixing cyanobacteria, they may help make up for the nitrogen loss from ecosystems. We assessed cryptogam biomass on the ground, boles and branches in Quercus costaricensis dominated stands near the tree line in the Cordillera de Talamanca, Costa Rica. Nitrogen fixation was assayed using 15N2 uptake. Total cryptogam biomass was 2 977 kg ha−1, with 67% being found on the lower branches. Bryophytes and chlorolichens made up 53% and 44%, respec- tively, of the biomass. Half of the bryophyte mass was composed of the liverwort Plagiochila heterophylla, and 66% of the chlorolichen of Lobariella pallida. There were no significant differences in nitrogen fixation rates between the cryptogam species, with a mean rate of 5.04 µg N g−1 day−1 during the predominantly wet condition in the forest. The overall nitrogen input from fixation was 6.1 kg N ha−1 year−1, of which 78% came from bryophytes, 18% from chlorolichens, and 4% from cyanolichens. Only 2.0% of the fixation occurred in cryptogams on the ground, whereas 67%, 24%, and 7% occurred on the lower branches, boles, and upper branches, respectively. These results show that tree epiphytes constitute a significant source of nitrogen for these forests, due to the trees’ large surface area, and can make up for the nitrogen lost from these ecosystemsUCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de BiologíaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Biodiversidad y Ecología Tropical (CIBET

Understanding the link between benefits from protected areas and their relationship with surrounding communities: an exploration in Costa Rica

Protected areas are an essential strategy in preserving natural resources. A central aspect of protected area management is to maintain and improve their relationship with surrounding communities given that local conflicts often occur over the existence or expansion of protected areas due to land-use restrictions. This study seeks to understand the link between perceived socioeconomic and environmental benefits from protected areas and the perceived strength of the relationship between 12 of these communities and their corresponding protected areas in Costa Rica. In total, 365 door-to-door interviews were conducted to collect data, and a logistic model and correlations were used to analyse the results. We found there is a significant link between the strength of the relationship between the community and protected area and the number of perceived socioeconomic benefits from the protected area; however, such a link does not exist with environmental benefits. This finding suggests that policy makers and protected area managers need to better develop and explain, in a participatory and integrated fashion, socioeconomic benefits from protected areas to communities since the successful long-term management and survival of protected areas hinges on these relationships. In this way, the desired goals of preserving habitats and biodiversity can be supported.Las áreas protegidas son una estrategia esencial en la preservación de los recursos naturales. En la actualidad, un aspecto central del manejo de las áreas protegidas es mantener y mejorar su relación con las comunidades circundantes dado el frecuente conflicto por la existencia y expansión de áreas protegidas debido a restricciones en el uso de la tierra. En este estudio, buscamos entender la conexión entre los beneficios socioeconómicos y ambientales percibidos por las comunidades sobre las áreas protegidas y la fortaleza de la relación percibida entre 12 de estas comunidades y sus correspondientes áreas protegidas en Costa Rica. En total, se realizaron 365 entrevistas casa a casa para recolectar los datos, y se utilizó un modelo logístico y correlaciones para analizar los resultados. Encontramos que existe una conexión significativa entre el nivel de percepción de la relación comunidad-área protegida y el número de beneficios socioeconómicos percibidos del área protegida; sin embargo, dicha conexión no se mantiene para los beneficios ambientales. Este resultado sugiere que los responsables de la formulación de políticas y los administradores de áreas protegidas deberían desarrollar y explicar mejor, de una manera participativa e integradora, los beneficios socioeconómicos adicionales de las áreas protegidas hacia las comunidades, por cuanto la gestión a largo plazo y la supervivencia de las áreas protegidas dependen de la relación que tienen con sus comunidades circundantes. De esta manera se pueden apoyar los objetivos deseados de preservación de los hábitats y la biodiversidad.Les aires protégées sont un élément clé pour la préservation des ressources naturelles. L’un des principes fondamentaux de la gestion des aires protégées est de maintenir et d'améliorer leurs relations avec les communautés locales, car l'existence ou l'expansion des aires protégées est souvent source de conflits, en raison des restrictions d'utilisation de ces terres. Cette étude vise à comprendre le lien entre la perception des avantages socio-économiques et environnementaux créés par aires protégées, et la qualité des relations entretenues par 12 communautés avec leurs aires protégées au Costa Rica. 365 entretiens en porte-à-porte ont été menés, puis analysés grâce à un modèle logistique basé sur des corrélations afin d’en déduire les résultats. Nous avons constaté que la qualité des relations entre la communauté et l’aire protégée influence la perception des avantages socio-économiques provenant de l’aire protégée; cependant ceci n’est pas le cas pour les avantages environnementaux. Ces résultats suggèrent que les décideurs et les gestionnaires d'aires protégées se doivent de mieux présenter et expliquer, de manière intégrée et participative, les avantages socio-économiques liés aux aires protégées, car la gestion à long terme et la survie des aires protégées repose sur leurs bonnes relations avec les communautés. La réalisation des objectifs attendus de la préservation des habitats et de la biodiversité sera ainsi favorisée.SFS-Center for Sustainable Development Studies in Atenas, Costa Rica, the National University of Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ingeniería::Instituto Investigaciones en Ingeniería (INII

First evidence for an aposematic function of a very common color pattern in small insects

Many small parasitoid wasps have a black head, an orange mesosoma and a black metasoma (BOB color pattern), which is usually present in both sexes. A likely function of this widespread pattern is aposematic (warning) coloration, but this has never been investigated. To test this hypothesis, we presented spider predators (Lyssomanes jemineus), both field-captured and bred in captivity from eggs, to four wasp genera (Baryconus, Chromoteleia, Macroteleia and Scelio), each genus being represented by a BOB morphospecies and black morphospecies. We also used false prey, consisting of lures made of painted rice grains. Behavioral responses were analyzed with respect to presence or absence of the BOB pattern. In order to better understand the results obtained, two additional studies were performed. First, the reflection spectrum of the cuticle of the wasp and a theoretical visual sensibility of the spider were used to calculate a parameter we called “absorption contrast” that allows comparing the perception contrast between black and orange in each wasp genus as viewed by the spider. Second, acute toxicity trials with the water flea, Daphnia magna, were performed to determine toxicity differences between BOB and non-BOB wasps. At least some of the results suggest that the BOB color pattern may possibly play an aposematic role.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Biología Celular y Molecular (CIBCM

Reproductive phenology, allometry, and spatial organization of dioecious species of the genus Virola (Myristicaceae)

Orientadores: Vera Nisaka Solferini, Marlies SazimaTese (doutorado) - Universidade Estadual de Campinas, Instituto de BiologiaResumo: O resumo poderá ser visualizado no texto completo da tese digitalAbstract: The abstract is available with the full electronic documentDoutoradoEcologiaDoutor em Ecologi

Wind creates crown shyness, asymmetry, and orientation in a tropical montane oak forest

In a cloud forest dominated by Quercus costaricensis, the gap size between the crowns was consistent and crowns were asymmetrical, being elongated perpendicular to the prevailing wind direction. A wind storm of 20 m/s removed 1.5% of the leaves, con-sistent with the idea that wind abrasion shapes tree crowns.Natural Sciences and Engineering Research Council/[]/NSERC/CanadaUCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí

The Paradigm of Forests and the Survival of the Fittest

Forest ecosystems have been used for human populations over millennia. Even today, forests provide a large amount of resources and environmental services for modern human populations, but disturbance caused by human activities has altered and threatened these ecosystems across the globe. Forests are distributed over a large span of latitudes and elevations, and as a response, there is large variability in their characteristics. Different kinds of forest vary in their structure, species composition, patterns of diversity, patterns of disturbance, and regeneration. Here we explore the characteristics of gymnosperm and angiosperm-dominated forests, and explore the ecological characteristics of three main forest biomes: boreal, temperate, and tropical forests in terms of productivity and structural and species diversity. Finally, we explore fine scale variability within these ecosystems and the implications of natural and human disturbance on these environments.UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí

Allometry and stilt root structure of the Neotropical palm Euterpe precatoria (Arecaceae) across sites and successional stages

The lack of secondary meristems shapes allometric relationships of the palms, infl uencing 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 terrain inclination and palm size affected stilt root structure at two sites in Costa Rica. We dissected the root cone into eight variables and used principal component analysis to summarize their correlation structure. The fi t of the stem diameter – height relationship to the stress, elastic, and geometric similar- ity models was examined using data from 438 palms. Terrain inclination did not affect stilt roots, whose structure was determined by palm size. Palms under 1 m showed geometric similarity, whereas palms above 1 m had slope values that were one and a half times higher, independent of successional stage, and did not adjust to any mechanical model. Taller palms departed from these models when they were large because they had stilt root support. We conclude that height in E. precatoria is constrained by structural support at the base and that diameter at the base of the stem and stilt roots balances height increments over all the size ranges examined. KeyOrganization of Tropical Studies/[]/OTS/Costa RicaUniversidad de Costa Rica/[111-A3-129]/UCR/Costa RicaUCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí

Demographic variation across successional stages and their effects on the population dynamics of the neotropical palm Euterpe precatoria

• 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 influence demographic parameters, but the relationship between these gradients and the species life history, habitat requirements, and degree of variation in demographic traits remains elusive. • Methods: We used the palm Euterpe precatoria to test the effect of successional stage on plant demography within a continuous population. We calculated demographic parameters for size stages and performed matrix analyses to investigate the demographic variation within primary and secondary forests of La Selva, Costa Rica. • Key results: We observed differences in mortality and recruitment of small juveniles between primary and secondary forests. Matrix models described satisfactorily the chronosequence of population changes, which were characterized by high population growth rate in disturbed areas, and decreased growth rate in old successional forests until reaching stability. • Conclusions: Different demographic parameters can be expressed in contiguous subpopulations along a gradient of successional stages with important consequences for population dynamics. Demographic variation superimposed on these gradients contributes to generate subpopulations with different demographic composition, density, and ecological properties. Therefore, the effects of spatial variation must be reconsidered in the design of demographic analyses of tropical palms, which are prime examples of subtle local adaptation. These considerations are crucial in the implementation of management plans for palm species within spatially complex and heterogeneous tropical landscapes.Fundación CRUSA/[]//Costa RicaOrganization for Tropical Studies/[]/OTS/Costa RicaUniversidad de Costa Rica/[111-A3-129]/UCR/Costa RicaUCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí

Depredación de la paloma piquirroja (Patagioenas flavirostris) por el gavilán bicolor (Accipiter bicolor): observaciones sobre el modo de consumo y vigilancia

El gavilán bicolor depreda principalmente aves de tamaños variables. En esta comunicación reportamos la depredación de la paloma piquirroja por parte de un gavilán bicolor cerca del parque Nacional Volcán Poás, Costa Rica y la relación entre el comportamiento de vigilancia y consumo. La presa ya estaba muerta cuando iniciaron las observaciones. El gavilán manipuló y consumió parte de la presa en el suelo de un pastizal rodeado de árboles. El gavilán removió plumas, consumió carne y vigiló los alrededores. El depredador disminuyó la tasa de vigilancia y consumió más a medida que el tiempo transcurría y oscurecía. Creemos que este comportamiento podría aumentar el riesgo del depredador, pero maximiza la adquisición de recursos cuando la obtención de alimento es impredecible.UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí