Award: OCE-2350541

Consumer interactions are key drivers shaping the assembly of natural communities over ecological and evolutionary time scales. Environmental forces can intensify or moderate these interactions and change marine biodiversity.  Recent marine studies demonstrate that predation can be stronger at lower latitudes where water temperatures are higher. Since most of these studies are conducted across latitude the mechanisms shaping those biogeographic patterns remain unclear. Factors other than temperature covary with latitude, complicating field tests of temperature-dependent consumer control. We examined how the 2023-2024 El Niño, temperature increases and associated changes to marine upwelling altered consumer interactions on Tropical Eastern Pacific reefs.

 

We used consumer exclusion experiments across ten coral reef sites, distributed along a gradient of upwelling activity in Panama and Costa Rica.  We found that (1) invertebrate biomass and cover are higher when predatory fish are excluded and (2) upwelling activity (with concurrent increases in productivity and decreases in ocean temperatures) lead to higher recruitment rates, increased biomass, and a reduction in top-down control by consumers. El Niño events generally increase water temperature and weaken upwelling, but we only recorded increases in ocean temperatures during the non-upwelling season in 2024 and no increases in average temperatures during the 2024 upwelling season. In addition to the experimental results above, we identified several introduced species in our experiments on the reefs.  These are notable records because while we have reported these on the mainland in ports and marinas, these results show spread of non-native species to more distant natural habitats on coral reefs in the Topical Eastern Pacific.  These results increase our understanding of how ecological interactions and environmental forces affect community assembly and the maintenance of marine biodiversity on coral reefs in the Tropical Eastern Pacific and how these interactions can provide biological resistance to marine invasions on tropical reefs. 

 

Last Modified: 01/30/2026
Modified by: Mark E Torchin