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Research topics in:
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Botany |
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Barber-Gormley, Peregrine, “Ethnobotany and the study of optimal natural ecological conditions of an endangered cycad, Zamia skinneri, for the enhancement of future cultivation techniques.” Adv. Rafael Ocampos. Colorado. 1999. 77 pp. The environmental conditions of two wild populations of the Costa Rican cycad, Zamia skinneri, were studied in Baltimore, Matina county, Limón province, Costa Rica. Slope and soil conditions were analyzed to determine the effects on population abundance. The rise and the run of slopes was measured in a total of 62 plots containing the two populations. Higher mean population densities were found on moderate to steep slopes, than on flatter slopes. Both physical and chemical soil conditions were analyzed from two composite soil samples taken separately from the two population sites. Soil conditions showed considerable differences between the two populations. The information found in this study, in conjunction with previous studies, seems to show that Z. skinneri prefers sands and sandy loams over soils with high clay contents. However, no definitive statements about the influence of chemical composition correlating with changes in population abundance, can be made. The information collected in this study, will aid in the artificial cultivation of this endangered ornamental plant. An ethnobotanical study was conducted in the Cabecar community of the Chirripo indigenous reserve in order to assess current knowledge of Zamia skinneri, and increase local awareness. The study determined that the majority of the population can identify the plant, but lack knowledge of its medicinal use. Out of four families interviewed, one used the sap of this plant to speed the healing of wounds. Also, out of 21 elementary school students, three stated that their families used the plant for wound healing, and one of those stated that it could also be used to eliminate the parasitic skin larva, Papalomoyo (Leish maniases). Bay, Robin, “Comparison of plant species in three differing sucessional communities of the tropical dry forest in Palo Verde National Park, Guanacaste.” Adv. Michael McCoy. Colorado College. 1999. 15pp. This study looked at the secessional process of the tropical dry forest in Palo Verde National Park, Guanacaste during March and April. Differences in tree species composition, frequency, diversity and percent cover of the understory were compared between three communities of tropical dry forest that exhibited varying degrees of disturbance by cattle grazing. The first (P1) was not grazed between 1980 - 86, but now is grazed intermittently. The other two (P2 and P3) were grazed in the past but have not been for the last twenty years, although P3 burned in 1989. All three areas are bordered by mature relatively undisturbed forest.The plant species diversity was found to be significantly greater in the forests than the pastures and also greater at site 2 than either of the others. The percent cover of woody species in the understory exhibited the same trends as well, although in Site 2, percent cover was the same in the forest and pasture suggesting greater recovery at this site. Supporting this, the species composition of the two habitats at Site 2 showed greater similarity than at sites 1 and 3. The frequencies of the most common species in each site were compared between sites and habitats. The frequencies of those species most commonly foraged by cattle were also compared. Blank, Vicki L., “A Comparison of Forest Structure and Tree Species Composition in Three Successional Sites of Cloud Forest in Monteverde, Costa Rica.” Adv. M. Sc. Dora Ingrid Rivera. Grinnell. 1999. 17pp. This study analyzes the changes in tree species composition of Monteverde?s neotropical cloud forest as areas of forest recover from human disturbance. Data on tree species diversity and abundance were collected in a primary forest and secondary forests of approximately eight and forty years. With respect to DBH, height, and density of individuals, the forest structure of the 8-year forest was simple in comparison to those of the 40-year and primary forests, while the 40-year and primary forests were similar in structure. However, with respect to species richness, diversity indices, and levels of oligarchy, the species composition of the primary forest was more complex than those of both the secondary forests. Indices of similarity between forest types also support the conclusion that forty years is not sufficient for a secondary forest to regain the biodiversity present in a primary cloud forest. Brenner, Jacob, “Branch attachment and survival of fallen epiphytic bromeliads (Bromeliaceae), Cordillera de Talamanca, Costa Rica.” Adv. Christopher Vaughan. Lawrence University. 2000. I studied survival of fallen epiphytic bromeliads in a neotropical montane rain forest on the Dúrika Biological Reserve, Puntarenas Province, Costa Rica during March and April, 2000. The objective of this study was to determine the influence of host branch attachment on survival of these bromeliads on the forest floor. I sampled, identified and characterized 1,496 plants in ten species. Results showed significantly different survival percentages across five attachment classes: large branch, small branch, twig or bark, detached with roots and detached without roots. Survival depended on attachment, decreasing with branch size. I discuss the principal factor as branch substrate security. Candelaria, Karin, "The Effects of Habitat on Plant Species Composition in Páramo Las Vueltas, Cordillera de Talamanca, Costa Rica." Adv. Carlos Valerio. Knox. 1991. 28pp. The effects of habitat on the composition of plant species were analyzed within various plant communities of Páramo Las Vueltas, in the Cordillera de Talamanca, Costa Rica during March and April, 1991. Special consideration was given to soil composition and climatic factors within the area. The páramo is loosely defined as the type of vegetation which occurs between the timberline and the snow line in the tropic belt. Five sites were chosen on the páramo in order to sample plant community types. Within each site, five quadrants were surveyed, each of twenty-five square meters. Frequency, density, and cover were measured for each plant species. An importance value was assigned to each species based on the sum of the relative values of these parameters in order to have an idea of the dominance of the species within the area. The depth of the top layer of soil was also measured for each site. Soil samples were taken and analyzed for the content of organic and inorganic material. From these tests, it was found that the species composition of plant communities is affected less by variations of edaphic conditions and more by local differences in climate, topography, wind, sunlight, and inclination of slope. Crandall, Suzannah, "Fungal Infestation and pest Damage on Theobroma cacao Pods in a Premontane Wet Forest zone of Costa Rica." Adv. Christopher Vaughan. Beloit. 2003. This study will document the occurrence of fungal infestation and pest damage to Theobroma cacao pods over a period of approximately five months as the pods mature. Approximately 1000 pods will be sampled from different heights and tree clones to provide a detailed record of specific causes of damage and to quantify pod mortality. This information will be used to determine options for controling damage in the future. |
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Davidson, Anna, "Habitat Preferences and Comparative Sugar Analysis in Leaves of Selected Symplastic Phloem Loading Species of Bignoniaceae and Acanthaceae in the Humid Forest of Sarapiquí and the Dry Forest of Santa Rosa, Costa Rica." Advisor: Walter Marín. Ripon College. 2005. 21pp. Phloem loading is the starting point of long distance nutrient transport. There are two types of phloem loading. Symplastic loading occurs through the plasmodesmata-connected cytosol of cells. Apoplastic loading requires at least one extracellular step through cell walls. Symplastic phloem loaders have unique characteristics that distinguish them from apoplastic phloem loaders such as intermediary cells (a specialized companion cell), highly branched plasmodesmata more so on the bundle sheath cell, and they translocate raffinose and stachose unlike apoplastic loaders that transport only sucrose. It has been observed that intermediary cells have evolved at least five different times. What are the adaptive advantages of symplastic phloem loading? Why are there two mechanisms of phloem loading? To help answer this question, a floristic analysis was done and illustrated that symplastic phloem loaders are most prevalent in tropical environments. What are the characteristics of a tropical environment that might be involved in adapting to loading symplastically? The objective of this research is to compare the habitat preferences of two symplastically phloem loading families, Bignoniaceae and Acanthaceae in two extremely different environments (dry tropical forest and wet tropical forest) within Costa Rica, a country that significantly represents a tropical environment. This research may help us to narrow down characteristics of tropical environments that might have aided in the evolution of symplastic phloem loading. It was found that there is almost equal diversity of Bignoniaceae species in both the dry forest and the wet forest. However, there is a higher density of Bignoniaceae in the dry forest. Acanthaceae has a higher number of species in La Selva versus the dry forest of Santa Rosa. Families as a whole do not seem to prefer one environment to another, their preference is at the species level. Leaf material of each species was taken and ground with ethanol. The sugars of these samples will be later analyzed at Cornell University using HPLC to identify the sugars, and the amount of sugar between species of the same family that occur in these two different environments. Driessen, Brad, "Savanna Succession in the Premontane Moist Forest of Turrúcares, Alajuela Province of Costa Rica." Adv. Alvaro Castaing. Lawrence. 1992. 58pp. An ecological study of relic forest sites along the Tizate River located near Turrúcares, Alajuela undergoing a plant succession to Savanna forest. Frequency, density, and dominance values of trees were found to determine the importance of species within the sites. As a result of the annual burning of pastures, substitution of larger, perhaps native tree species by smaller fire resistant species was found to be occurring. This is leading to the degradation of soils and conditions of the water shed. The researcher offers some appropriate techniques to do Social Forestry to increase the productivity of the land to reverse the process of savanna formation. Gerstner, Brett Justin, "Distribution and Diversity of Epiphytic Ferns on Tree Bases in Costa Rican Montane Cloud Forests." Advisor: Maarten Kappelle. Lawrence University. 2005. 24pp. This study assessed the diversity and distribution of epiphytic ferns on tree bases in the upper montane oak dominated cloud forests near San Gerardo de Dota, in the Talamanca mountains of Costa Rica. Epiphytic ferns dwelling on the bases of 150 oak and non-oak tree stems were sampled in three ecologically different forest stands: one in a mature, old-growth forest on the drier Pacific slope, and two in Successional forests inhabiting both the drier Pacific slope and wetter Atlantic slope. In total, 206 fern individuals were recorded, distributed over 16 species in seven genera. Using different diversity indices, the wetter Atlantic stand turned out to be most species rich, being 1.6 to 1.7 times richer than the drier Pacific stands. Atmospheric humidity seems to be the main factor determining species diversity. Two distinct species groups were found in two forest stands. Increased stem diameter seemed to only slightly enhance the diversity of epiphytic ferns on stem bases. Four epiphytic fern species seem to have a preference for specific tree stem diameter classes, though further study is needed to analyze this pattern. It is concluded that humidity seems to be much more important than successional age as a key factor in determining fern species diversity. Thus, it is postulated that on the long term climate change (in this case, changing precipitation patterns and cloud cover) may locally have a greater impact on epiphytic fern species diversity than forest clearing and subsequent natural recovery. Gordon, Sarah, "20 Medicinal Plants Used by the Bribri Indians in Coroma, Talamanca." Adv. Juan Diego Alfaro. Colorado. 1992. 48pp. This is an ethnobotanical study of the medicinal plants used by the Bribri Indians in Coroma, Talamanca. The study site is the Bosque Comunal, a 3,000 ha. portion of virgin tropical premontane wet forest used by the Bribri to practice and preserve their traditional ways. I identified 20 medicinal plants used by the Bribri that are found in the Bosque Comunal and in the Talamanca Valley at the base of the area. Information on how the Bribris use these medicinal plants, and how they are tied into Bribri mythology is discussed. In addition, the significance of the Bosque Comunal in light of the constant pressure of deforestation in the Talamanca Valley is included. Finally, suggestions for future projects are discussed. Galey, Kelly, "Physical and Phytosociological Observations on the Natural Regeneration of Cordia alliodora, Upala, Northern Costa Rica." Adv. Alvaro Castaing. Macalester. 1998. 24pp. Over the months of March and April of 1998, a study of the natural regeneration of Cordia alliodora, commonly known as laurel, was conducted in Pueblo Nuevo de Bijagua, near Upala in northern Costa Rica. The main objective was to compare the growth of laurel in different stages of progression. Biometrical data was collected on seedlings and on mature trees. The distance between both seedlings and mature trees to the nearest mature tree was measured. Health was measured in seedlings as a ratio of diseased leaves to total leaves. The presence or absence of nodules in seedlings was recorded. The only significant difference found between the two populations was the density which was higher in primarily seedling populations. A more diversified plant population was found in the primarily seedling population. Growth of seedlings, in terms of height and diameter, were significantly related to their distance from the nearest laurel tree by regression analysis. The presence of nodules was significantly related to the diameter and height of the seedling by regression analysis, but had no significant relation to the health of the seedling. There was also a significant correlation between the circumference at breast height of mature trees and the proximity of the nearest mature tree. While the growth of seedlings found growing within the mature population was not significantly different from those in seedling populations, seedling density was affected. Additionally, both seedlings and mature trees growth decreased as the distance to the nearest neighboring tree decreased. Groome, Sarah, "Arrabidaea chica (Bignoniaceae): an ethnobotanical study of its biology, domestication potential and uses by two indigenous groups, the Bribri and Cabécar of Costa Rica." Adv. Rafael Ocampo. Colorado. 1998. 29pp. The first formal study of Arrabidaea chica (Bignoniaceae) in Costa Rica was conducted during March and April, 1998, in the Cantón of Matina, Limón, Costa Rica. The first half of the study focused on learning about the biology and ecology of the vine, by establishing parcels in different forest environments located in the farm Bougainvilla S.A. in La Esperanza de Matina, Limón. Cuttings of the plant were taken and grown in artificial conditions to obtain an idea of its domestication ability by asexual reproduction and to observe its potential as a non-timber forest product. The second half of the study focused on investigating the knowledge and uses of this vine by two indigenous groups, the Bribri and Cabécar speaking peoples of Costa Rica, by the use of informal interviews. The most common use of Arrabidaea chica for the Bribri is as a red dye used to color fibers to make baskets and other forms of craftsmanship; uses by the Cabécar remain ambiguous. This research provides preliminary data that the plant is found abundantly in forest areas with more light, in various soil types, has important usefulness for the Bribri of Costa Rica and has economic potential as a non-timber forest product, medicinal plant and natural colorant. Hart, Georgia M., "Entomophilous pollination of coffea arabica (Rubiaceae) and its pollination interations with neighboring wild confamilials." Adv. Luis Diego Gómez. Grinnell. 2003. This project will investigate the reproductive consequences of insect pollination for Coffea arabica and its interactions with other Rubiaceae in forest surrounding coffee plantations near San Vito in the southern Talamanca range. Insect pollinators will be identified and the percentage of pollination of C. arabica through insect vectors and other means such as wind pollination and autogamy will be calculated. The effects of coffee pollen and pollinators will be tested on neighboring confamilials. Hayford, Kyla, “A comparison of understory plants in three successional cloud forests in Monteverde, Costa Rica.” Adv. Dora Ingrid Rivera. Macalester. 1999. 20pp. Succession is the natural change in species composition after a disturbance. Forests can usually recover from natural disturbances yet human-derived disturbances, such as deforestation, may be too overwhelming to recover from. Generally, a mature forest will have greater diversity. I studied the effects of deforestation by performing a quantitative inventory of the species in the understory at the Sky Trek reserve in the Monteverde Cloud Forest. 8 year, 40 year and primary forests were compared and analyzed according to the Shannon-Weiner Diversity Index, overall density, family richness, and percent similarity. The preliminary study supported the Intermediate Disturbance Theory in which the family richness and diversity were highest in the 40 year forest and then decreased in the climax primary forest. According to the Shannon-Weiner Diversity Indices, the 40 year forest has recovered to the level of a primary forest. However, the percent similarity, family richness, and overall density suggest that the secondary forests have not fully recovered. The successional pathways are characterized by five major families. Thelypteridaceae and Urticaceae are colonizing families where as Dryopteridaceae is a climax family. Both Rubiaceae and Piperaceae are abundant in all stages of succession. |
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Johnson, Kaia, “The phenotypical characterization and harvesting of Smilax (Cuculmeca) in the tropical forest of Limón, Costa Rica.” St. Olaf. 2000. 30pp. A study of Smilax spp. (Cuculmeca) was conducted during March and April, 2000, in the county of Matina, Limón, Costa Rica. Research took place in secondary tropical forest in the Agroecological Garden Bougainvillea S.A. Investigation involved the phenotypical characteristics, domestication and conservation of Cuculmeca. Thirty-nine adult plants were found, measured and observed. Samples of flowers and fruits were taken; and seeds were counted and planted. Pieces of rhizome containing shoots were planted in parcels in the tropical forest. Ethnobotany determined the method of harvest and indicated that three traditional classes of Cuculmeca exist: blanca, roja and morada. Information from this investigation will provide preliminary data which may be used in future studies on Cuculmeca. Kashi, Natalie, "Cyclanthaceae and Weevils." Adv. Luis Diego Gómez. Colorado. 2003. This study will research the pollination syndrome of one or two species of the Carludovicoideae subfamily of Cyclanthaceae. Evidence of the pollination pattern of Cyclanthaceae will provide more information on the phylogeny of Cyclanthaceae and the relationship between ancient insects and plants. Kroese, Jesse, "Gall richness in the Paramo and high altitude oak forest of Cerro de la Muerte with an emphasis on Melastomataceae." Adv. Paul Hanson. Macalester. 1998. 12pp. Variations in galling species richness and galling patterns in tropical plant families are two aspects of gall ecology that have not been extensively studied. This investigation addressed these questions through two sub-studies. Study A: Two hypotheses which attempt to explain the variation in species richness of gall-formers in different life zones were tested in three Costa Rican life zones: the montane rain forest (high altitude oak forest), the Paramo and the wet tropical forest. The number of galling species found over time was recorded for transects 2 x 50 meters in dimension. Galling richness in oak forest and wet tropical forest was not significantly different ( = 0.738, df = 1, p = 0.384), while there were highly significant differences in the Paramo-Oak forest comparison ( = 26.31, df = 1, p < 0.0001 ) and Paramo-Cańo Palma comparison ( = 12.14, df = 1, p < 0.000493). These results did not conclusively support or refute the two hypotheses in question. Study B: Seven species of Melastomataceae were surveyed for galling patterns in the Paramo and high altitude oak forest. Six of the species contained galls; nine types of galls were present, with an average of 0.806 galls per plant. Galls per plant frequencies did not closely follow the normal (Gaussian) distribution. Kurth, Valerie, "A Comparison of the Natural Regeneration of Carapa guianensis in a Cleared Pasture and in a Primary Forest in the Northern Zone of Costa Rica (Upala)." Adv. Alvaro Castaing. Macalester. 1998. 14pp. The natural regeneration capabilities of the tree species caobilla (Carapa guianensis) were studied on a cattle farm in Pueblo Nuevo de Bijagua (canton: Upala; province: Alajuela, Costa Rica) during the months of March and April, 1998. The purpose of the study was to compare the regeneration of caobilla in a cleared pasture and in a primary forest. The diameter and height of seedlings growing beneath mature trees was measured and their herbivory status was observed. The distance between mature trees and seedlings was measured. Seedling diameters and heights were greater in the forest than the pasture (F = 5.86; df = 1, 962; p = 0.0157; F = 123.63; df = 2, 745; p < 0.00009, respectively). Percent herbivory was greater in the pasture than the forest (F = 5.86; df = 1, 20; p = 0.0251) and the mean distance between mature trees and seedlings was greater in the forest (F = 13.84; df = 2, 396; p < 0.00009). These results suggest vertebrate predators are responsible for seed dispersal in the forest while pasture seedlings tend to develop where they land beneath the mature tree. Forest seedlings also develop faster and suffer less from herbivory than pasture seedlings. Kusmin, Victor N., "Dracontium sp. (Araceae): Un estudio etnobotánico con los indígenas cabécar de Costa Rica." Adv. Rafael Ocampo. 1997. An unidentified species of the little studied genera Dracontium (Araceae) was studied formally for the first time in the northern part of the Talamanca region, Limon. The first half of the study focused on a population growing within the agroecological system, of cacao (Theobroma cacao), timber, native and other domesticated species, present at the farm Bougainvilla S.A. in La Esperańza de Matina, Limon. An attempt was made to identify the species, and gain a knowledge of the biology and ecology of the plant in respect to its potential as a non timber forest product. To this end, collections were made, and various measurments taken from a range of plant sizes and compared. The second half of the study focused on investigating what remains of the knowledge of the traditional and historical uses of hombrón by the indigenous Cabécar speaking peoples. Various formal and informal interviews were conducted, in Spanish, and recorded. The most commonly known use of this genus is its function as a remedy for the venemos terciopelo (Bothrops atrox). While very little remains of the Cabécar knowledge of the traditional uses of this, one of the largest, species of Dracontium, it does posses economic potential as a non timber forest product, in respect to a tropical agroecological system. Lila, Rasa, "Dracontium gigas (Araceae): Ethnobotonical Study and Enrichment of the Tropical Forests with a Medicinal Plant Used by the Bribri and Cabécar Indigenous People of Costa Rica." Adv. Rafael Ocampo. Colorado. 1998. 53pp. In the Spring of 1997, a formal study on an herbaceous plant Dracontium gigas (Araceae) was conducted for the first time in the northern part of the Talamanca region of Limón, Costa Rica. This plant is used medicinally by the Bribri and Cabécar Indigenous people of Costa Rica to treat venomous snake bites. The first study focused on the investigation of the biological aspects of Dracontium. There was a need for further research on its ecological limits, taxonomy, life cycles, history and use by the Indigenous peoples. The present study focused on these aspects as well as the planting of Dracontium in the forest to enrich it, and preparing for future investigations. If Dracontium is shown to be an important forest plant resource, it could contribute to a group of plants called nontimber forest products. These plants offer an economic alternative to cutting down the Tropical Forests. The preliminary results found the studied Dracontium plants to be the species D. gigas. The findings supported that Dracontium thrives in disturbed environments and agroecological systems more than primary forest. It was also found to be an extremely important forest plant resource for the Indigenous Bribris and Cabécar to cure venomous snake bites. |
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Lobato, Tonya, "A Field Guide: An Introduction to the Vegetation of the Volcán Cacao Biological Station" Adv. Eric Olson. Lawrence University. 1997. 27pp. The plant and tree species listed in this guide were collected from the 800 meter trail through the pre-montane tropical moist forest accessing the Volcán Cacao Biological Station. They represent some of the most common or conspicuous species growing along the trail, and provide only a small sample of the astounding plant diversity found there. This guide was written in order to provide visitors and students of Volcán Cacao a means of familiarizing themselves with the vegetation whether it be for academic purposes or simply individual interest. As much information as possible was recorded about each species. All listed species include a basic pictoral representation along with a description pointing out distinguishing characteristics of the plant or tree. The map included in the beginning of the guide points out specific trees along the trail with numbers corresponding to the numbered listings in the book. For the species listed on the map, depending on the abilities of the navigator, identification can be quite easy; the others, however, may require a bit more effort. Careful observation, along with the information provided in the book, should enable most individuals to correctly match the remaining species with their live counterparts. Each species is listed under its appropriate family; the families are arranged in alphebetical order. Logback, Judy, "A Study of Successional Process in 'Openings' in the Premontane Tropical Rain Forest of San Bosco." Adv. Alvaro Castaing. Beloit. 1993. 20pp. The ecological process of tropical rain forest succession in forest 'openings' was studied by comparing characteristics in the stages of pioneer, early secondary, late secondary and virgin forest located in the Cordilleras of Costa Rica. The microclimates and biodiversity, frequency, and density of scientific families were investigated, in premontane forest successional sites of the San Bosco Region. Lucas, Rachel, "An Evaluation of Nectar Production and Quality of Heliconia tortuosa Griggs (Heliconiaceae) with Ambient Temperature." Advisor: Luis Diego Gómez. Lawrence University. 2005. 50pp. This research evaluates the interaction between environmental factors that may cause variations in nectar production and quality. Understanding the causes of variation in nectar production may help with further insight into co-specfic relationships between hummingbirds and flowers. Las Cruces Biological Station in San Vito, Coto Brus, Costa Rica provided an abundance of heliconia plants to study during March and April of 2005. Data collection included temperature, nectar volume, nectar concentration and pH every two and a half hours from 0630 hr to 1600 hr. In addition, weather data was collected from a weather station at Las Cruces; these environmental factors were used to analyze ambient factors in relation to nectar production and quality. Nectar production and total sugars concentration has a significant relation with time. Temperature and other ambient factors were found to have very little effect on nectar production and concentration. Meisner-Bogdahn, Hanna, "Effects of Climate Change in Monteverde Cloud Forest on Survival, Growth, Reproductive Success of Platystele microtatantha: A Proposal." Adv. Karen Masters. Colorado. 2003. This study will address how climate change during the dry season in Monteverde and more specifically, the decrease in dry season mist frecuency, affects survival, growth and reproductive success of the Platystele microtatantha orchid species. It will also investigate the water conservation strategies used by P. microtatantha under conditions of decreased mist frequency compared with conditions of more consistent mist. Okrent, Rachel, “Distribution and abundance of Smilax spp. (Cuculmeca and Zarzaparrilla) in three permanent plots in secondary growth tropical humid forest on the Caribbean coast of Costa Rica..” Adv. Rafael Ocampo. Grinnell. 2000. 20pp. The distribution and abundance of Smilax spp. (Cuculmeca and Zarzaparrilla) was investigated in three permanent plots in secondary growth tropical humid forest in Limón, Costa Rica. These medicinal plants, thought to be in danger of extinction, demonstrated a stable population structure at the study site, Garden Bougainvillea S.A. Plants were categorized into the following three development states: regeneration, juvenile, and adult. The census revealed 600 plants of the common name Cuculmeca and 94 of Zarzaparrilla. There exist 565 regenerates, 70 juveniles and 56 adults. Ethnobotanical investigation, performed in conjunction with the ecological study, revealed differences in the knowledge regarding Cuculmeca between indigenous and non-indigenous people of the area. Oyama, Ryan, "Characterization of a Premontane Wet Forest Dominated by quercus seemanii in Costa Rica." Adv. Dr. Alvaro Castaing. Lawrence. 1995. 16pp. This study attempts to characterize a Tropical Premontane Wet Forest dominated by Oak (Quercus seemanii). This forest was located at a relatively low altitude on a ridge near El Carmen de Parrita, Costa Rica. Plant samples were collected along a one kilometer transect and identified to at least the family level. Profile measurements of the trees along the transect were also made. From this data, a picture of the community composition was obtained. The forest was found to be highly diverse and transitional to a Lower Montane Wet Forest due to a steep climatic gradient that exists along the ridge. The regeneration of Oak seedlings was also studied and no significant correlation to light was found. Pearson, Duane, "Population Dynamics of the Cedro Macho Tree, Carapa guianensis in the Tiskita Biological Reserve." Adv. Alvaro Castaing. Lake Forest. 1992. 12pp. Population dynamics of a ridge top population of Carapa guianensis was studied in the Tiskita biological reserve. Basal area, seed size and dispersal patterns, biomass production, germination success rates, and seedling dispersal were all studied. Basal area for this ridge top community was 7.66 m2/ha. Average seed weight was 74.2g. Leaf Litter production for the forest as a whole was 22.6g. dry weight per m2 per week. 21% (4.75g.) of this biomass weight was contributed by C. guianensis. Dispersal patterns fell into the preestablished norms for this species: the number of seeds present on the ground increases as distance from the trunk of the parent tree increases. 75.5% of these seeds germinate. The highest concentration of yearling seedlings (smaller than 1.5 meters altitude) was found within one meter of the parent tree. The hypothesized reason for this pattern of seedling dispersal is an increase in soil humidity and organic material next to the trunk. This pattern of seedling dispersal had no apparent effect on the dispersal patterns of the adult and juvenile members of this species. The results of this study were compared to the results of two studies that were done with C. guianensis in its climax habitat: moist, poorly drained soils. Population density was much lower on the well drained slopes of the Tiskita reserve. Seed size was significantly increased, double what had previously been reported. Seed dispersal patterns were not changed by differences in terrain. |
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Peterson, Snow Brook, “Differences in flower characteristics and insect visitor composition for two species of Ageratina (Asteraceae) on Cerro de la Muerte, Costa Rica.” Adv. Paul Hanson. Grinnell. 2000. 18 pp. This study investigated differences in insect visitor rates and flower characteristics between two superficially similar species of the genus Ageratina (Asteraceae) -- A. ixiocladon and A. reticulifera. The study was conducted during March and April of 2000 between the towns of Jaular and Villa Mills, Costa Rica, in a tropical montane rainforest life-zone. I made a series of observations of different individuals of each plant species and found that A. ixiocladon was more frequently visited by bumblebees than A. reticulifera, while A. reticulifera was more frequently visited by tachinid flies. Both types were visited by equal numbers of total visitors and syrphid flies. The corolla tubes of A. ixiocladon are significantly longer than those of A. reticulifera, and their flower heads also average a higher number of florets. The differences in visitor composition, which may be correlated to the differences in flower characteristics, contradict the theory of similar looking Asteraceae acting as generalists in the insects they attract (i.e. the insects do not distinguish between species). Reed, John, "The Pollination Biology of Conostegia xalapensis (Melastomataceae)." Adv. Sally Bianco. Grinnell. 1990. 17pp. During the months of March and April 1990 the pollinated biology of Conostegia xalapensis (Melastomaceae) was studied in the area of Santa Elena, Costa Rica. The hermaphroditic flowers are physically open to pollination for one day (0600-2100) although the stigmata remain receptive to pollen for another 24 hrs. C. xalapensis was found to be an outcrosser with a 99.6% fruit set from manually cross-pollinated flowers vs. a 4.5% fruit set from manually self-pollinated flowers. The principal pollinators were found to be Melipona beechei and M. fasciata (diurnally active stingless bees of the family Apidae). Rickards, Anna, "Abundance, Diversity, and Distribution of Epiphytic Plants on Fallen Trees in a Tropical Premontane Rainforest." Adv. Dr. Walter Marín, UCR. Oberlin College. 2006. This study assesses the diversity, distribution, and abundance of all the epiphytic plants found on three different fallen trees in the tropical and premontane rain forest (wet forest) of the Organization of Tropical Studies' (OTS) La Selva Biological Field Station and Reserve. All the epiphytes found on the tree were recorded along with their height and position. Representative species were collected for the purposes of identification and collecting height and weight measurements. Data has been organized in various ways to obtain a full picture of the epiphytic cover of each tree, including both Plant Height and Plant Weight vs. Circumference of Phorophyte, Distribution of Common Families among Branch Size Categories, and a map of all the epiphytes found on each tree indicated by family. Ridley, Caroline, “Cecidomyiid galls on Peperomia species in a tropical montane cloud forest on Cerro de la Muerte, Costa Rica.” Adv. Paul Hanson. Grinnell. 2000. 16pp. During the months of March and April 2000, I investigated a little known gall type induced by members of the family Cecidomyiidae, also known as the gall midges, on plants of the genus Peperomia on Cerro de la Muerte, Costa Rica. This study was a preliminary examination of the morphology of these galls, as well as a general characterization of the Peperomia plants which are used as hosts. Results indicate that one species of cecidomyiid is responsible for inducing morphologically similar galls on three of eleven species of Peperomia found within the study site. Variation in gall color seems to be due to differences in gall age while variation in gall size appears to be attributable to multiple factors including host species, age, and the number of larvae within the gall. Schoeb, Brent, "An Analysis of Primary and Second Growth Montane Rain Forest Near La Trinidad de Dota, Costa Rica." Adv. Carlos Valerio. Lawrence. 1991. 19pp. In this study a series of plots within 40 ha. of primary montane forest and 30 ha. of second growth forest were analyzed. The secondary forest is the result of five years growth after this section of land was clearcut, with the exception of several large trees which remain today. The area for this study is located in the Cordillera de Talamanca, Costa Rica, at an elevation of ca. 2700 m. 25 m2 plots were used within both forest types to identify the woody species present (individuals d.b.h. > 20 mm.) and to map these individuals. A direct replacement of the dominant species in the primary forest was observed in the secondary forest, presumably due to remnant seed trees present in the latter. The notable exception to this was the lack of Quercus spp. in the secondary forest, possibly due to predation on acorns of these species. In addition, data regarding the basal area, height, and diameter at breast height for each forest type are presented here. Stavina, Nina, “Ethnofarmacology and Methods of Reproduction of Juanilama (Lippia Alba) in the Caribbean Region of Costa Rica.” Adv. Rafael Ocampo. Colorado. 1999. 20pp. I conducted an integrated study of ethnofarmacology and biology of a medicinal plant Lippia alba during the months of March and April. The study was done in the Agro-ecological garden of Bougainvillea S.A. and in its surrounding communities of Matina County, Limon Province, Costa Rica. Juanilama is the common name of Lippia alba in Costa Rica. My first goal was to determine the knowledge of the communities about the Juanilama concentrating on its traditional usage and if in fact it was used by interviewing elementary school students and their parents. Juanilama continues to be one of the well known plant, but the knowledge of its traditional uses has decreased. Education and revaluation of this cultural aspect is in need. Continuous extraction of Juanilama from the wild and inability to adequately domesticate Juanilama puts it in danger of disappearance. In result diminishes people using it and benefitting from its medicinal properties. I have performed numerous propagation tests using asexual means of reproduction by cuttings of branches of the plant. The result of these tests showed the most economic and effective method of reproduction of Juanilama in the Caribbean region of Costa Rica. Strauss, Ben, "Measuring the Effects of Syzygium jambos (Rosy Apple, Myrtaceae) on Patterns of Understory Plant Diversity in a Tropical Premontane Forest." Advisor: Gerardo Ávalos. Knox. 2005. 20pp. The exotic tree species, Syzygium jambos (Rosy Apple, Myrtaceae), was studied at the Municipal Forest of Atenas, Alajuela, Costa Rica, from February 28 to April 22 of 2005. The objective of the study was to determine what effect S. jambos is having on understory other understory species is indicative of the invasiveness and competitiveness of the exotic. No relationship was observed between the density of the plant and canopy cover data or distance from the edge of the forest, signifying a fairly homogenous forest that has already been substantially colonized by the invader throughout. Data indicates that S. jambos is having a negative effect on understory diversity and so advice concerning the removal and control of the species is given. Mechanical or biological controls are the best bets for this forest fragment, given sufficient research, funds and labor force to ensure a successful control program. Also discussed is the forest's status as an area of protection for drinking water of neighboring communities. Extirpation of exotics should be considered as long as water protection is not affected. |
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Wetzler, Erica, "A Study of the Successional Process in Clear Cut Areas of El Carmen de Parrita, Costa Rica." Adv. Alvaro Castaing. St. Olaf College. 1995. 40pp. The successional process was investigated at three sites of land near El Carmen de Parrita, Costa Rica. Each site was divided into quadrants and samples of each species within random quadrants were collected. Height and leaf area measurements were also recorded for each plant. Results indicated that while diversity, frequency, and density of scientific families are directly related to the number of years since an area had been cut, leaf area is more closely related to changes in altitude. Temperature readings were recorded as well. Results demonstrated that temperature was inversely related to altitude and directly related to proximity to the native forest. |
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