CDF-EAF volunteer collecting climatic data at the CDF climate station in Puerto Ayora.
(Photo by Mandy Trueman)
A La Niña climatic event is currently underway in the Pacific region, with possible impacts on all Galapagos ecosystems from January to May 2011. The Climate Change Initiative of the Charles Darwin Foundation (CDF) aims to inform on likely ecosystem responses to changes in the frequency and strength of El Niño and La Niña events, rainfall patterns, fluctuations in sea level and sea temperature, and acidification. As part of this ongoing Initiative, CDF monitors Galapagos marine and terrestrial climate indicators to capture baseline data that will enable future projections. To complement this effort, CDF announces the launch of its new online Galapagos Climate Database, available in English and Spanish.
Online access to these data provides researchers worldwide with vital information that can facilitate the understanding of long-term climate conditions in Galapagos and beyond. CDF Theme Leader of Biodiversity Assessment, Dr. Frank Bungartz, notes that: “The online Climate Database contains records collected by CDF continuously since 1964, making it an extremely valuable tool for scientists.” The CDF Galapagos Climate Database, to be updated monthly, includes air and sea temperatures, and rainfall and humidity records.
La Niña is the lesser-known cold sister of the El Niño phenomenon, part of the natural climatic variation called ENSO (El Niño Southern Oscillation) that is centered on the equatorial Pacific and that influences weather patterns worldwide. During La Niña events, the Eastern Pacific, including Galapagos, experiences colder conditions than usual – something felt in the archipelago over the past few months with everyone wearing warm jackets and scarves. According to CDF data, the October 2010 Sea Surface Temperature (SST) was 2°C (4°F) cooler than average for this time of year. Galapagos hot-season precipitation is correlated with the temperature of surrounding waters: atmospheric convection associated with elevated SSTs generates rainfall whereas reduced SSTs suppress it. Therefore, if cooler than normal sea temperatures persist into the hot season from January to May, drought is possible.
The ecological impacts of cool La Niña droughts include reduced terrestrial biological productivity: plants fail to germinate, produce seed, or survive. This can create bare patches that facilitate the subsequent spread of introduced species, exacerbating invasive species impacts in the archipelago. Reduced plant productivity also lowers the amount of food available to native and endemic Galapagos fauna, limiting the reproductive success and wellbeing of animals such as Darwin’s finches. The agricultural sector can also suffer from dry conditions. Rain-fed short cycle crops such as maize are most affected. The cattle and dairy sector is also impacted because low rainfall and cool temperatures limit pasture productivity. The strongest drought associated with a La Niña event since the 1960s occurred in 1985 (see graph), when almost no rainfall was recorded between December 1984 and May 1985.
CDF monthly rainfall totals for Puerto Ayora exhibit extreme climate conditions during the 1980s. The major El Niño event of 1983 brought huge rainfall, whereas the 1985 La Niña event created a prolonged dry period.
La Niña events also impact the Galapagos marine environment. Extended periods of cooler than normal conditions bring increased productivity and hence more food for marine iguanas, seabirds, sea lions and small fish. However, some tropical species such as branching corals and warm-water reef fish are negatively impacted: Corals rapidly overgrown with algae may die and tropical fish may migrate to areas less affected by cool waters. CDF Director of Marine Sciences, Dr. Matthias Wolff, adds that: “Colder waters may also decrease the production of eggs and larvae in lobsters and sea cucumbers and increase the time for larvae to develop into juveniles. This may lead to an increased larval mortality and a reduced number of juveniles entering the stock.” Such impacts would affect both the fishing and tourism sectors.
Mandy Trueman, climate researcher and CDF collaborating scientist, observes that: “At this stage it is uncertain how strong the La Niña event will be or whether significant effects will be felt in Galapagos. However, climate records illustrate that cooler temperatures during January to May mean less rainfall, so there is a risk of drought from January until the garúa (mist and drizzle) returns in June or July.” Advance preparation for drier conditions may include storing water, repairing leaky pipes, safeguarding against wildfire, reducing livestock herds, postponing cultivation, and prioritizing irrigation regimes.
Galapagos climate data are newly accessible online via the CDF Galapagos Climate Database.
The CDF Knowledge Management and Biodiversity Assessment programs benefit from the support of the Galapagos Conservancy, the Galapagos Conservation Trust, and anonymous individual donors.
The CDF Climate Change Initiative benefits from the support of The Leona M. and Harry B. Helmsley Charitable Trust, the Galapagos Conservancy, Conservation International, the World Wildlife Fund-Galapagos, and the Ecuadorian Air Force.
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