A new publication in the journal ‘Global Climate Change’ detailing the decline of marine organisms in the Galapagos Archipelago following human exploitation and climate change (El Niño, grazers and fisheries interact to greatly elevate extinction risk for Galapagos marine species) makes for somber reading.
A series of events, including the 1982 El Nino, overfishing and the appearance of urchins that destroy coral, has altered the islands’ marine ecosystems. At least 45 Galapagos species have now disappeared or are facing extinction. That suggests future climate change driven by human activity will have an major impact on the islands’ wildlife.
The report.. found that the islands have yet to recover from the intense El Nino climate event of 1982 to 1982, which triggered abnormal weather conditions. That event destroyed coral reefs in the archipelago, many of which had persisted for at least 400 years. However, overfishing significantly weakened the marine ecosystem’s ability to recover from the devastation caused by the El Nino. In particular, fishermen removed so many large predatory fishes and lobsters from the islands’ seas, that huge numbers of sea urchins were able to colonise the area. They then overgrazed the coral, damaging it further and preventing it re-establishing.
As a result, 45 species are now globally threatened. All live on the Galapagos, and most are found nowhere else. (Read more over at BBC News)
Several species from the archipelago are listed as ‘probably extinct’ (including the black spotted damselfish and the 24 rayed sunstar), and other threatened species include the Galapagos sea lion, marine iguana, Galapagos penguin and pink cup coral.
Interestingly though, it’s not only the the ‘charismatic’ species are suffering:
Above are two photographs from the Charles Darwin Research Station – on the left from 1974, and the right taken again in 2003. Back in the 1970’s, the rocks were covered by a dominant brown algal species (Bifurcaria galapagensis), which as the name suggests is an endemic species that thrived in the intertidal regions (upto 6m depth). According to researchers at the institute, a mass mortality and dieback occured between January and March 1983, leaving the barren exposed rock that you see in the photograph on the right. This species is now assumed to be extinct since the mid-1980’s, as extensive searches across the entire Galapagos archipelago have revealed nothing.
“The Galapagos, the Rosetta Stone of evolution, is now teaching us about the far-reaching impacts of climate change on ocean ecosystems,” says report co-author Professor Les Kaufmann from Boston University, US.
“Nowhere on Earth are the combined impacts of climate change and overfishing more clearly defined than in the Galapagos Islands,” says co-author Sylvia Earle of the US National Geographic Society.
“Decades of data link recent fishing pressures to disruption of the islands’ fine-tuned systems, making them more vulnerable to natural, and anthropogenic changes in climate.” (Read More)