Communities in DSpace
Select a community to browse its collections.
Recent Submissions
Connectivity of the sea urchin Diadema mexicanum A. Agassiz, 1863 (Echinoidea, Diadematidae) in the Pacific coast of Costa Rica
(2025-03-13) Carvajal Rojas, Sofía; Brenes Guillén, Laura; González Sánchez, Kaylen; Cordón Krumme, María Isabel; Montiel Barrantes, María Paula; Alvarado Barrientos, Juan José
Diadema mexicanum is essential for controlling algae and maintaining coral dominance on coral reefs. Despite its importance as a key grazing species, little is known about the genetic structure and connectivity of its populations. Molecular markers are particularly sensitive to genetic differences between disjunct populations, providing insight into their resilience to environmental changes. This study seeks to genetically characterize D. mexicanum populations on coral reefs along the Pacific coast of Costa Rica. Sampling took place between May and October 2019. DNA was extracted from each sample, and microsatellite markers were subsequently amplified using primers designed for D. antillarum and Strongylocentrotus nudus. Data analysis was performed using GeneMarker, R Studio, and Structure. The analysis revealed lower genetic diversity than previously reported for these microsatellites, resulting in high inbreeding coefficient values. This could be attributed to several factors, such as high reproductive success variation and null alleles. A weak genetic structure
was found among sampling sites, but this structure was independent of the region where samples were collected. No isolation by distance was detected, suggesting genetic connectivity and gene flow within populations. Future studies would benefit from analyzing a wider range of molecular markers and ensuring more equitable sampling across sites.
Half of Atlantic reef-building corals at elevated risk of extinction due to climate change and other threats
(2024-11-15) Gutiérrez, Luis; Polidoro, Beth; Obura, David; Cabada Blanco, Francoise; Linardich, Christi; Pettersson, Emma; Pearce Kelly, Paul; Kemppinen, Krista; Alvarado Barrientos, Juan José; Alvarez Filip, Lorenzo; Banaszak, Anastazia; Casado de Amezua, Pilar; Crabbe, James; Croquer, Aldo; Feingold, Joshua S.; Goergen, Elizabeth; Goffredo, Stefano; Hoeksema, Bert; Huang, Danwei; Kennedy, Emma; Kersting, Diego; Kitahara, Marcelo; Kruzić, Petar; Miller, Margaret; Nunes, Flavia; Quimbayo, Juan Pablo; Rivera Sosa, Andrea; Rodriguez Martınez, Rosa; Santodomingo, Nadia; Sweet, Michael; Vermeij, Mark; Villamizar, Estrella; Aeby, Greta; Alliji, Khatija; Bayley, Daniel; Couce, Elena; Cowburn, Benjamin; Nuñez Lendo, Isabel; Porter, Sean; Samimi Namin, Kaveh; Shlesinger, Tom; Wilson, Bryan
Atlantic reef-building corals and coral reefs continue to experience extensive decline due to increased stressors related to climate change, disease, pollution, and numerous anthropogenic threats. To understand the impact of ocean warming and reef loss on the estimated extinction risk of shallow water Atlantic reef-building scleractinians and milleporids, all 85 valid species were reassessed under the IUCN Red List Categories and Criteria, updating the previous Red List assessment of Atlantic corals published in 2008. For the present assessment, individual species declines were estimated based on the modeled coral cover loss (1989–2019) and projected onset of annual severe bleaching events (2020–2050) across the Atlantic. Species traits were used to scale species’ relative vulnerability to the modeled cover declines and forecasted bleaching events. The updated assessments place 45.88%–54.12% of Atlantic shallow water corals at an elevated extinction risk compared to the previous assessments conducted in 2008 (15.19%–40.51%). However, coral cover loss estimates indicate an improvement in reef coverage compared to the historic time-series used for the 2008 assessments. Based on this, we infer that, although remaining dangerously high, the rate of Atlantic reef coral cover decline has surprisingly slowed in recent decades. However, based on modeled projections of sea-surface temperature that predict the onset of annual severe bleaching events within the next 30 years, we listed 26 (out of 85) species as Critically Endangered in the IUCN Red List. Each of these species had previously been listed under a lower threatened category and this result alone highlights the severe threat future bleaching events pose to coral survival and the reef ecosystems they support.
A story of disturbance and loss: historical coral reef degradation in Bahía Culebra, North Pacific of Costa Rica
(2025-03-03) Fabregat Malé, Sònia; Alvarado, Juan José
Introduction: Climate change and other multiple stressors have globally caused the collapse of many coral reefs. Understanding how coral reefs have responded to previous disturbances is key to identify possible trajectories in the face of future more frequent and intense disturbances.
Objective: We review the ecological history of coral reefs in Bahía Culebra, a historically important area for coral reef development in the North Pacific of Costa Rica, which has suffered extreme deterioration in the last decades.
Methods: We assessed historical traits of coral reefs using both historical and recent data, divided as follows: (i) the “pre-disturbed” period (1970–2000), (ii) the early degradation period (2000–2010), and the degraded period (2010–present day).
Results: Forty years ago, Bahía Culebra harbored the highest coral species richness in the Costa Rican Pacific, with high live coral cover (> 40 %). Signs of early degradation were observed after El Niño events and unprecedented coastal development that caused anthropic eutrophication, which led to coral death and a shift to macroalgae-dominated reefs. In the last decade, a steep decline in live coral cover (1–4 %), the loss of many reefs, and a decrease in reef fish diversity and abundance were recorded.
Conclusions: To promote the recovery of coral reefs in the bay, we propose management actions such as marine spatial planning, mitigation and monitoring of stressors, and ecological restoration. The latter could help turn the tide by increasing live coral cover, eventually leading to ecosystem functionality recovery, with spill-over effects on reef-associated communities, including local coastal communities. Nonetheless, such actions need governmental and local support; thus, raising awareness through environmental education and citizen science programs is key for the long-needed conservation of coral reefs in Bahía Culebra.
Guardianes del Ecosistema: herramienta lúdico-didáctica para fomentar la conservación de ecosistemas vulnerables en estudiantes de primaria en Costa Rica
(2024-10-17) Zúñiga Madrigal, Jorge; Angulo Vásquez, John; López García, Yesenia; Barrantes Montero, Gilbert; Alvarado Barrientos, Juan José; Perdomo Velázquez, Héctor
Esta investigación presenta una propuesta de educación ambiental bajo la modalidad de maleta didáctica, que consiste en un compendio de 12 actividades lúdico-didácticas originales, dirigidas a estudiantes de primaria que se encuentran en la etapa de operaciones concretas definida por Piaget. Las actividades se encuentran circunscritas en el contexto de dos ecosistemas vulnerables en Costa Rica; bosque montano alto y arrecife de coral. La propuesta fue ejecutada en cuatro centros educativos localizados en el Cerro de la Muerte y Bahía Culebra respectivamente. Dos de los centros educativos fueron sometidos al material correspondiente al ecosistema donde se ubican, mientras que los otros centros recibieron un proceso comparativo con ambos tratamientos, para conocer la influencia de la cercanía con el recurso en la afinidad por él. Se realizaron tres pruebas enfocadas en el diagnóstico del conocimiento biológico y percepción sobre distintas especies de vida silvestre emblemáticas de la zona y actividades humanas favorables y desfavorables para el ambiente. Para el análisis de estadístico se empleó un Modelo Lineal Generalizado Mixto con un límite de confianza del 95 %. Se registró una diferencia en los resultados para al menos una de las tres pruebas diagnósticas en todos los centros educativos. Uno de los centros educativos sometidos a doble tratamiento registró calificaciones medias superiores para el ecosistema de arrecifes de coral en dos de las tres pruebas diagnósticas. Esta propuesta es efectiva para transmitir conocimiento sobre biología y conservación de ecosistemas vulnerables por medio del desarrollo de pensamientos ambientalmente responsables. Se comprobó una mejora en la percepción de especies de vida silvestre y se destaca la posibilidad de trasladar el diseño de las actividades desarrolladas a otros ecosistemas.
Coral reefs restoration initiatives in Costa Rica: ten years building hope
(2025-03-03) Alvarado Barrientos, Juan José; Evans, Katharine; Kleypas, Joan A.; Marín Moraga, José Andrés; Mendez Venegas, Mauricio; Pérez Reyes,Carlos; Sandoval, Marylaura; Solano, María José; Villalobos Cubero, Tatiana
Introduction: Costa Rica has been recognized worldwide for its high biodiversity and the conservation actions it has implemented. One of the most iconic ecosystems are coral reefs, which have experienced strong anthropogenic and natural pressures in recent years. To ensure these ecosystems’ preservation and services, a series of coral restoration initiatives have emerged in the last ten years along both Pacific and Caribbean coasts.
Objective: To document the different advances of the various coral restoration initiatives Costa Rica’s Pacific and Caribbean coasts.
Methods: This review focuses on the implementation of the different reef restoration efforts, indicating the restoration techniques used, the coral species used in the nurseries, as well as the general results of survival and growth.
Results: The first coral restoration project in Costa Rica occurred in the 1990s and was the only such effort until the 2010s. In 2013, a pilot project began in the Golfo Dulce area, which was later replicated in other areas of the country, such as Manuel Antonio, Sámara, and Bahía Culebra on the Pacific coast, and more recently in Punta Cahuita in the Caribbean. Various artificial structures have been used as nurseries in the water column such as trees and ropes, and benthic structures such like A-frames, tables, and spiders, the former being very effective for branching species (Pocillopora spp.), while the rest have worked successfully both for branched and massive species (Pavona spp. and Porites spp.). The results shows a growth rates have been between 6 and 9 cm/year, with survival of 60–90 % of the branching and massive colonies. All sites were seriously affected by the El Niño 2023 phenomenon, with high bleaching values and loss of colonies in the nurseries and on the reef.
Conclusion: Despite geographic and oceanographic distinctions, these projects have emphasized local engagement and perception of coral reefs, fostered intersectoral public-private collaborations for financial and human resources, and operated within established governmental regulatory frameworks. All projects face vulnerabilities such as El Niño events and Harmful Algal Blooms.