The Implications of Climate Change for Galapagos

April 21, 2016

By guest author and GC Adjunct Scientist Dr. James Gibbs of the State University of New York’s College of Environmental Science and Forestry (SUNY-ESF).

Sea Lion in GalapagosThe planet’s climate is changing. There’s no reason to expect anything different for the Galapagos climate as well. The questions are: What changes can we expect and how fast will they happen? Will the unique Galapagos flora and fauna be able to adapt quickly enough? Is there something that decision-makers can do now to ensure the long-term protection of Galapagos biodiversity?

Several explorations of this topic have all ended on the same note: it’s difficult to recommend anything specific when we don’t really know what is likely to transpire. Will Galapagos get wetter or drier? Warmer or cooler? Will its already dynamic climate become more extreme, more stable, or just stay within its current bounds? Decision-makers in all sectors, from natural resource managers to those responsible for human welfare, urgently need scientifically-based information about the potential nature and impacts of global climate change specifically on the Galapagos Islands.

The main challenge is that Galapagos is not an “average” place by any measure. You, like me, probably live somewhere on a small patch of habitat on a very large continent. Global climate models are complex, but their predictions can be reliably “down-scaled” to specific sites on large continents — like the towns and cities where most of us live.

Galapagos is another matter. Despite the Archipelago’s vastness and remoteness, the islands themselves are small. Moreover, a complicated and ever-changing mix of ocean currents constantly percolates through the Archipelago driving sea surface temperatures, which heavily influence the air temperature and rainfall.

You get the picture…Galapagos is not like where most of us live. Galapagos climate experiences unusually complicated interactions between the marine environment — primarily the altering predominance of different ocean currents — and the land. How changing global climate will play out on the complicated topography of these isolated islands is unclear.

So we need to get a reliable prognosis for the climate in Galapagos before any specific prescription can be made. Our emphasis will be on making that diagnosis. The work will be very technical (modelling different scenarios), but will include a vitally important communication component. And at the end of the year-long project, we will be able to provide a firm guidance for decision-making based on the best climate projections available ”down-scaled” specifically to Galapagos, to best protect Galapagos and its unique flora and fauna into the future.

Nesting sea turtle in Galapagos

The work will inform many important questions. For example, how might tortoises be affected? Higher temperatures might trigger altitudinal migrations and potentially impact tortoise nesting success. Higher rainfall may actually generate more food for tortoises, at least on the lower islands like Española and Pinzón. But more rain might also boost invasive insect species such as fire ants, which could lead to increases in predation on hatchlings.

And how might sea turtles be affected? Beach conditions regulate nest temperatures, which determine hatchling sex ratios. Higher temperatures could alter egg development, favoring the development of female offspring. Sea turtles also depend heavily on marine algae, their main food source; algal production is very sensitive to sea surface temperature.

A marine iguana feeds on algaeObviously, beach flooding and erosion from sea level rise are other important considerations: no beaches = no sea turtle nests. Similarly, marine iguanas are heavily affected by algal production — marine algae being their main food source — but also by air temperatures that affect egg development, and by rainfall that affects nesting.

What makes Galapagos currently so important for large predators like sea lions, hammerhead sharks, and penguins is “upwellings” of dense, deep-water current carrying cold, nutrient-rich water — these could be reduced by ocean warming; something we know happens during El Niño events. Current conditions also foster development of coral reefs, including cold-water coral species that are widespread in Galapagos, which would be threatened by rising ocean temperatures.

Mangroves are another concern. These forests that occupy the nexus between ocean and land are a nursery for many marine fish species and habitat for many birds, including the mangrove finch, a critically endangered species unique to Galapagos. Sea level rise could shift mangrove forests inland if it doesn’t happen too quickly.

And how about the tree-like Opuntia cactus, those icons of Galapagos? Opuntias are the keystone food of many terrestrial animals over much of the Archipelago that is arid, and during heavy rains, cactus get waterlogged and may topple over. Given the many species that depend on the magnificent Opuntias of Galapagos, cactus species may be another important target for long-term protection in an era of climate-change.

Opuntia cactus in Galapagos

There are many other angles to pursue, but when we complete our one-year study (for which we are currently seeking funding), we expect to achieve:

  • Completion of a scenario evaluation based on down-scaled predictions from global climate models to generate scientifically-based predictions of likely climate trends in Galapagos in the upcoming decades;
  • Development of a website that presents key outcomes and implications, along with an interactive tool that enables users to explore implications of climate change scenarios in the context of their area of concern.

Together, these outcomes will put us all on a much firmer footing for understanding what is most likely to transpire due to changes in the Galapagos’ climate over the next 50 years and, given that, what we might consider doing to adapt, with the long-term goal to preserve and protect. Please stay tuned.

Dr. James Gibbs is Professor of Vertebrate Conservation Biology and Associate Chair of the Department of Environmental and Forest Biology at the State University of New York (SUNY-ESF). He has partnered with Galapagos Conservancy for many years in efforts to restore giant tortoise populations in Galapagos through the Giant Tortoise Restoration Initiative, and is a frequent guest contributor to the GC blog.

Photo credits, from top: sea lion © JJ LaBella; sea turtle © Susan Christensen; marine iguana © Michael Scupine; Opuntia © Mary Traveland.

Category: Guest Contributors,

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  1. Great article… my complimentss to Prof. Gibbs for drawing attention to this important topic.
    Jack Grove
    Senior Author FISHES OF THE GALAPAGOS

  2. James, I’m hoping you will do a follow up article including the devastating effects of climate change on Nezoryzomys — the endemic Galapagos rodents. When the historic climate cycles prevail, their capacity to generate their own metabolic water and eat the caustic opuntia allows them to compete with Norway rats very well. But when the islands are wetter, those giant, aggressive European rats lay waste to the little Galapagos rats and their pups.

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