The Galapagos Islands are at a cross-road between human development, climate variability and change.  Without humans, its ecosystems evolved to cope with alternate changes between warm El Niño and cold La Niña events.  Both of these are increasing in frequency and intensity causing unprecedented and unpredictable ecological impacts.  Its isolation has been broken by global drivers of change - growth in tourism-immigration, alien-pests, and global markets.  Marine ecosystems are experiencing major changes and extinction events with unknown consequences to its functioning and the services they provide.

This work addresses the questions of Galapagos's marine-coastal ecosystem functioning and its resilience to the drastic and rapid transformations due to environmental change and variability, tourism and human growth, and export markets.

For two generic tropical-temperate bioregions, we developed qualitative models where the limits of the ecosystem resilience are tested under different environmental and socio-economic scenarios. The variables in the model interact via generalized Lotka-Volterra dynamics.  Environmental drivers and human social and economic subsystems interact via flows of resources, goods, and services. We specifically examined the consequences of environmental change (El Niño-La Niña) affecting productivity, basal resources and top-predators and we examined the effect of changes in fishing and how these affect tourism and fishers.

Results/Conclusions

All modeled systems are strongly influenced by environmental drivers that alter key components defining current bioregions and their biological members.  These changes in turn alter the ecosystem services (e.g. sharks, endemic biota, and food provision, etc.) that the socioeconomic subsystems depend on.  The changes in the temperate and endemic components and their services are the most affected.  This is explained by overall negative effects on all primary producers, including phytoplankton, due to the large residence of tropical oligothrophic waters during the expected prolonged and frequent El Niño events.  The response of primary consumers, sea urchins and herbivore fishes determine the recovery rates and sign of the responses, particularly in the temperate system.  Climate and ocean variability affects the quality and perceptions of the growing tourism with overall likely negative impacts.  Growth in fishing has a lesser but qualitatively important negative impact in key system components, particularly when fishing (commercial and sport) focus on top-predators (sharks, tuna and bill fishes).

If climate change and variability continue as predicted, the Galapagos marine-coastal ecosystems will change in irreversible ways.  Its resilience is strongly diminished by the human development, in particular industrialized tourism and fishing on top-predators.