IUCN Red List of Ecosystems: Coral Reefs of the Eastern Tropical Pacific
Abstract
Coral reefs in the Eastern Tropical Pacific (ETP), covering 140 km² (0.04% of the total global coral reef extent), are under increasing climate and anthropogenic threats. Coral reef development and species distribution in the ETP are conditioned by the characteristic isolation of the region and its strong environmental variability, including El Niño-Southern Oscillation (ENSO) events and upwelling. Focusing on coral reefs, marginal reefs, and their degraded/collapsed counterparts, located in Mexico, El Salvador, Nicaragua, Costa Rica, Panama, Colombia, and Ecuador, and encompassing five coastal and five oceanic ecoregions, we applied a standardized method to assess the risk of ecosystem collapse based on four criteria (i.e., decline in distribution, restricted geographic distribution, environmental degradation, and disruption of biotic processes and interactions). The ETP is characterized by a high overall risk of coral reef ecosystem collapse, with nine of the ten ecoregions classified as Critically Endangered and one ecoregion Collapsed. Across ecoregions, collapse risk was primarily associated with severe environmental degradation, particularly increasing thermal stress, although the relative contribution of other factors varied geographically. In three Critically Endangered ecoregions, severe environmental degradation was compounded by additional vulnerabilities, including reduced geographic distribution and disruption of biotic processes and interactions in Nicoya, reduced geographic distribution in the Eastern Galápagos Islands, and inherently restricted geographic distribution in Clipperton Atoll. The widespread high-risk status across both continental and oceanic ecoregions indicates that reef decline is not driven by a single pressure, but rather by the convergence of naturally marginal environmental conditions with accelerating climate and local anthropogenic stressors. These include thermal stress and coral bleaching, as well as land-based pollution, sediment and nutrient inputs, wastewater discharge, coastal development, and unsustainable fishing. The reef extent assessment conducted here represents the best available regional estimate and a standardized baseline for evaluating reef collapse risk. These results highlight the urgent need to safeguard the remaining coral-dominated reefs, persistent coral refugia, and herbivore and piscivore assemblages through coordinated regional management. Priority actions include reducing land-based pressures along continental margins, strengthening fisheries management and enforcement, maintaining ecological connectivity among reefs, as well as strengthening reef monitoring programmes regionally. Integrating these measures with transboundary governance, effective management of Marine Protected Areas, restoration actions, ecosystem-based management, direct conservation of resilient reefs, and climate-adaptation strategies will be essential to prevent further ecosystem collapse.
Related
BibTeX
@misc{arriagamadrigal2026iucn,
title = {{IUCN Red List of Ecosystems: Coral Reefs of the Eastern Tropical Pacific}},
author = {Andrea Arriaga-Madrigal and Manuel Olán-González and Juan P. Quimbayo and Juan José Alvarado and Imelda Amador and Arturo Ayala-Bocos and Luis Calderón-Aguilera and José Julio Casas-Maldonado and Amílcar Leví Cupul-Magaña and Priscilla Martinez and Ollin T. González-Cuellar and Rebeca Granja-Fernandez and Inti Keith and Andrés López-Pérez and Nicolas Moity and Damien Olivier and Georgina Ramírez-Ortiz and Héctor Reyes-Bonilla and Fernando Rivera and Jenny Carolina Rodríguez-Villalobos and Fabián A. Rodríguez-Zaragoza and Johanna Segovia-Prado and Omar Valencia-Méndez and Franz Smith and Mishal Gudka and Sonia Bejarano and Fernando A. Zapata},
howpublished = {EcoEvoRxiv},
year = {2026},
month = oct,
doi = {10.32942/x2pq5z},
url = {https://ecoevorxiv.org/repository/view/15665/},
note = {CC BY-NC 4.0},
}
RIS
TY - UNPB
TI - IUCN Red List of Ecosystems: Coral Reefs of the Eastern Tropical Pacific
AU - Andrea Arriaga-Madrigal
AU - Manuel Olán-González
AU - Juan P. Quimbayo
AU - Juan José Alvarado
AU - Imelda Amador
AU - Arturo Ayala-Bocos
AU - Luis Calderón-Aguilera
AU - José Julio Casas-Maldonado
AU - Amílcar Leví Cupul-Magaña
AU - Priscilla Martinez
AU - Ollin T. González-Cuellar
AU - Rebeca Granja-Fernandez
AU - Inti Keith
AU - Andrés López-Pérez
AU - Nicolas Moity
AU - Damien Olivier
AU - Georgina Ramírez-Ortiz
AU - Héctor Reyes-Bonilla
AU - Fernando Rivera
AU - Jenny Carolina Rodríguez-Villalobos
AU - Fabián A. Rodríguez-Zaragoza
AU - Johanna Segovia-Prado
AU - Omar Valencia-Méndez
AU - Franz Smith
AU - Mishal Gudka
AU - Sonia Bejarano
AU - Fernando A. Zapata
PY - 2026
DA - 2026/10/22
PB - EcoEvoRxiv
DO - 10.32942/x2pq5z
UR - https://ecoevorxiv.org/repository/view/15665/
AB - Coral reefs in the Eastern Tropical Pacific (ETP), covering 140 km² (0.04% of the total global coral reef extent), are under increasing climate and anthropogenic threats. Coral reef development and species distribution in the ETP are conditioned by the characteristic isolation of the region and its strong environmental variability, including El Niño-Southern Oscillation (ENSO) events and upwelling. Focusing on coral reefs, marginal reefs, and their degraded/collapsed counterparts, located in Mexico, El Salvador, Nicaragua, Costa Rica, Panama, Colombia, and Ecuador, and encompassing five coastal and five oceanic ecoregions, we applied a standardized method to assess the risk of ecosystem collapse based on four criteria (i.e., decline in distribution, restricted geographic distribution, environmental degradation, and disruption of biotic processes and interactions). The ETP is characterized by a high overall risk of coral reef ecosystem collapse, with nine of the ten ecoregions classified as Critically Endangered and one ecoregion Collapsed. Across ecoregions, collapse risk was primarily associated with severe environmental degradation, particularly increasing thermal stress, although the relative contribution of other factors varied geographically. In three Critically Endangered ecoregions, severe environmental degradation was compounded by additional vulnerabilities, including reduced geographic distribution and disruption of biotic processes and interactions in Nicoya, reduced geographic distribution in the Eastern Galápagos Islands, and inherently restricted geographic distribution in Clipperton Atoll. The widespread high-risk status across both continental and oceanic ecoregions indicates that reef decline is not driven by a single pressure, but rather by the convergence of naturally marginal environmental conditions with accelerating climate and local anthropogenic stressors. These include thermal stress and coral bleaching, as well as land-based pollution, sediment and nutrient inputs, wastewater discharge, coastal development, and unsustainable fishing. The reef extent assessment conducted here represents the best available regional estimate and a standardized baseline for evaluating reef collapse risk. These results highlight the urgent need to safeguard the remaining coral-dominated reefs, persistent coral refugia, and herbivore and piscivore assemblages through coordinated regional management. Priority actions include reducing land-based pressures along continental margins, strengthening fisheries management and enforcement, maintaining ecological connectivity among reefs, as well as strengthening reef monitoring programmes regionally. Integrating these measures with transboundary governance, effective management of Marine Protected Areas, restoration actions, ecosystem-based management, direct conservation of resilient reefs, and climate-adaptation strategies will be essential to prevent further ecosystem collapse.
ER -