Red List of Ecosystems: Risk assessment of coral ecosystems in the Colombian Caribbean

Abstract

Drivers of biodiversity loss have generated an increased risk of ecosystem collapse in the Anthropocene. Coral ecosystems are among the most diverse ecosystems, but at the same time also part of the most vulnerable and threatened ecosystems worldwide. This is the case of Wider and Colombian Caribbean coral ecosystems, which has a reduction of 50%, with extreme cases of 85% of their cover over the past decades. The methodology of the Red List of Ecosystems was implemented, for the first time, on the Colombian Caribbean to provide the assessment of collapse risk for coral ecosystems. To do this, the spatial and functional components of the ecosystem were analyzed using two of the Red List criteria (B and D) at three spatial scales (national, ecoregional, and biotic). For the former component, restricted distribution metrics were applied, and monitoring data of 20-year period (SIMAC) were used for the latter. Also, as a novel issue in coral functional risk assessment, macroalgae cover was considered, along with the percentage of live coral cover. The results indicated differences in the level of collapse risk depending on the spatial scale, whereby the national scale hid the most important risk dynamics of ecoregions and biotic scale overestimated the spatial risk. However, all ecosystem units at the three scales were assess from vulnerable to critically endangered, which means high-risk categories. Functional spatio-temporal analysis showed a general high-risk stability for the two variables chosen (fleshy algae cover and live corals) since 1998. These were complementary and necessary to propose the hypothesis of phase shift in the Colombian oceanic region, the area with the highest functional risk in the Colombian Caribbean. Finally, practical management recommendations were made based on the final assessment proposed by the risk map of coral ecosystems.